The Milford Mite:
England's Worst Ever?
by Adrian Duncan
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Following the conclusion of World War II, Britain went through a difficult period as the wartime industrial machine geared down and large numbers of de-mobilised Service personnel adjust faced the challenge of readjusting to civilian life. This left significant numbers of war workers looking for alternative peace-time employment. The country's infrastructure had suffered greatly in the conflict and many staples continued to be in short supply. Ready cash was tight and it was tough times all round for the average Briton. Winning a war is one thing—winning a peace is quite another!
The end of the war and the subsequent release of large numbers of technically-trained individuals both from the armed forces and the wartime industrial complex placed many skilled personnel at something of a loose end in a highly competitive economic environment. Not surprisingly, a number of them took the entrepreneurial approach by seeking to create their own opportunities through the application of their wartime skills to a "niche" market in which competition might be somewhat less fierce. Some of these individuals were modellers who looked seriously at the model market as a possible commercial outlet for their technical abilities.
Probably the best-known and most successful of these British post-war model-related ventures was the original Electronic Developments (Surrey), better known simply as ED. This venture was founded in 1946 by a group of former employees of the Parnall Aircraft company which had been engaged during the war in making Frazer-Nash gun turrets. However, in an often-repeated scenario following the cessation of hostilities, Ministry contracts were terminated and Parnall staff were left to find other employment. A group of them took control of their own destinies by establishing their own model-related business, and the soon-to-be famous ED company was the result of their efforts.
However, there were other model engine manufacturing ventures established on a far smaller scale at around the same time which signally failed to leave a lasting mark on the model industry. A number of these took the form of one or two-man "garden shed" operations. In one case (the Clan engines from Scotland), the manufacturing reportedly took place in a converted cowshed in Fife! For the most part, the products of these small-scale operations were manufactured in rather limited numbers and were mainly sold locally.
As might be expected, the quality of these grass-roots "cottage industry" manufacturing operations varied widely. Some, like the aforementioned Clan engines, were very well made and gave complete satisfaction in use. However, this was not the case for all such productions, and in this article we'll turn the spotlight on an early post-war engine that appears to have been the product of just such a small-scale manufacturing operation but has the reputation (deserved or otherwise) of having failed to come up to the generally-accepted British standards of the day. This is the often-maligned Milford Mite diesel of 1.41 cc displacement.
This intriguing little engine has fared very poorly over the years in terms of its reputation. Motor Boy Ken Croft has characterized it as "probably the worst diesel ever made in England". Mike Clanford commented in his A-Z compilation (page 130) that the engine's name was incorrectly spelled and that a more appropriate spelling would have been "Might" as in might (or might not) run!! The late OFW Fisher stated on page 26 of his Collector's Guide to Model Aero Engines that the Mite "left a good deal to be desired in many ways, and some consider that it falls roughly into the Slag category; although it in fact had a cylinder liner, and the engines would run". Well, some of them would anyway!
After the above litany, there's probably not a lot that we can say here that could make matters any worse for the reputation of the poor old Mite! However, in fairness to the much-abused little beastie, it seems only right that we should give it a fair trial before acceding to the general condemnation! This requires that we take a somewhat closer look at the engine and objectively determine the exact extent to which it truly lived down to its sorry reputation.
But before setting out on this voyage of discovery, I'd like to pay tribute to my good friend and valued colleague Kevin Richards. Kevin was unstinting of his time in tracking down published information on the Mite as well as supplying a number of images for me to use as illustrations to the following text. Kevin also read the draft and offered some very useful corrections and additions. So while I accept full responsibility for the content and conclusions presented in what follows, I'd like to make it very clear indeed that I couldn't have got to first base on this project without Kevin's help, which I hereby acknowledge freely and fully. Thanks, mate!
OK, on with our tale...
The Milford Mite was a 1.41 cc sideport diesel engine of basically conventional design but displaying some unusual features by the standards of the mid to late 1940's. It was made in relatively small numbers by a company known as the Milford Gauge Company of 5 Village Way East, Rayners Lane, Harrow, Middlesex (in the North-West sector of Greater London). Production appears to have been confined to the years 1947/48. The engine was evidently the brainchild of a certain Mr JR Smith, though very little is know about him.
Although the Mite was undoubtedly sold in model shops outside the London area and was even claimed by the makers to have found its way to foreign climes, it seems probable that the engine was sold locally for the most part, in many cases through direct sales from the factory. Indeed, buyers were encouraged to come to the workshop in Harrow to see their engines tested before they took delivery—a very direct form of marketing indeed, and one which displayed notable confidence in the engine's ability to perform on demand!
Despite the efforts of the makers to promote the engine, its present-day rarity leaves little doubt that overall production figures were quite low. Unkind critics of the engine have suggested that the rarity factor may in part be due to many of the engines that were sold ending up in the dustbin after their disgruntled owners had given up on them! It's our intention in this article to explore the basis (if any) for such a dismissive point of view, which has been widely expressed in the past.
As one would expect from a sideport engine of this vintage, the Mite was a long-stroke engine, although far closer to square dimensions than many other designs of the period. It had a nominal bore of 15/32" (.469" / 11.91 mm) and a nominal stroke of 1/2". (.500" / 12.70 mm for a stroke/bore ratio of 1.07:1 and a calculated displacement of 1.415 cc (.086 cuin). My own Mk III example measures up at more or less exactly these figures.
One very interesting feature of the Mite was the fact that its crankshaft was supported by a single ball race at the rear end adjacent to the crankweb. This actually makes it one of the very first British ball-race diesels, along with the contemporary BMP 3.5. The presence of the ball race and the thickness of the crankweb (see below) jointly explain the rather massive appearance of the front portion of the main crankcase casting.
The Mite was made in three distinct variants. The original Mk I model is pretty much in the unobtanium class in terms of its rarity - I have never encountered an example. However, I do have direct access to examples of both the Mk II and Mk III variants. My Mk II example of the Mite weighs in at a rather hefty 139 gm (4.90 ounces) including the tank. The all-up weight of my Mk III example, including tank, is only slight lighter at 137 gm (4.83 oz). This is still some 10 gm heavier than the contemporary aluminium case Mills 1.3 Mk I Series 2, which is perhaps the fairest benchmark against which to compare the Mite. The Mills Mk I Series II was produced from March 1947 to May 1948, which closely coincides with the probable production period of the Mite. In addition, it falls into the same displacement category. As can be seen in the comparative views, the Mk III Mite is actually a little more compact than the Mills despite its slightly greater weight and larger displacement. No doubt the ball race accounts for much of the weight difference.
The engine undeniably gives the impression of being one of the "garden shed" products mentioned earlier and of having been produced using a rather minimal machine tool inventory along with a fair amount of individual hand-work. This would be entirely consistent with small-scale artisan production and mainly direct distribution. The engine likely represents the efforts of a small group of individuals, presumably led by our mysterious friend Mr Smith, to earn a little extra money making a simple article that they could sell directly to the public.
As of July 1947, the Mk II version of the Mite was being advertised for sale at a price of £4 ready to run. In common with several other manufacturers of the period, the Milford Gauge Company also offered the engine in un-machined "kit" form at a price of 30 shillings, complete with blueprints and instructions. For an additional 20 shillings (50 shillings total), one could also get the engine in partially-machined form, but in this case one had to pay 3 shillings and 6 pence extra for the blueprint!
It actually seems possible that at least some of the sub-standard examples which have given rise to the Mite's unsavoury reputation may have been the products of less-than-skilled home constructors. Can't blame the manufacturers for that! Mind you, the corollary is equally true—some of the better examples (like my own Mk II, and Mk III) may be the products of highly talented hobbyists—the Motor Boys of their day! We would actually expect to find a wide range of quality standards in different examples of an engine which was built both by its original manufacturers and by their amateur machinist customers.
As one might anticipate with such a background, complete examples in good condition (by Mite standards ) are very rare today (2011) and prices in the £350 - £400 range have been seen earlier for a "good" one. Indeed, an example sold at the December 2003 Giddings auction for no less than £590! Such prices of course reflect the engine's rarity and curiosity value rather than its intrinsic merits. But no doubt Mr Smith would be dead chuffed!!
The Milford Mite does not seem to have survived long enough or made enough of a market impression to have attracted much real interest from the contemporary modelling media. As a result, this is one of the more poorly-documented British engines. In fact, the makers themselves created much of the record in relation to this engine through their advertising. We'll just have to do the best that we can on the basis of the few references that do exist coupled with an examination of several actual examples of the engine.
As already noted, three distinct variants of the Mite are attested in the record. On page 130 of Mike Clanford's well-known A-Z book includes photographs of two versions. A third appears in a captioned illustration in the 1947 first edition of Colonel CE Bowden's classic book Diesel Model Engines, although there is no accompanying description in the main text. The example in my own possession formed the basis for the original version of this article and is what Clanford calls a Mk II, but there's incontrovertible evidence in the form of manufacturer's advertising to confirm that it is in fact a Mk III. Clanford claims on unspecified evidence that very few of these models were made. Based on the scarcity of surviving examples, I'd say that this statement is probably true of all three variants.
The production dates for the engine are given by Clanford as 1947/48, and all the evidence in our possession is undeniably consistent with this dating. For starters, all of the manufacturer's advertising that Kevin Richards was able to dig up falls within these two calendar years. Furthermore, the Mite was not mentioned in the 1946 first edition of Laidlaw-Dickson's book Model Diesels, which implies that it had not yet appeared as of late 1946 when that book was completed. However, the original version of the Mite was certainly in existence in 1947 when Colonel Bowden was completing the first edition of his book, since an illustration of the engine appears in that work. It was also mentioned and illustrated in the 1947 second edition of Laidlaw-Dickson's book. All of this seems to confirm that the Mite was introduced in 1947 and that the version illustrated in Col. Bowden's first edition and Laidlaw-Dickson's second edition was the earliest of the three known variants.
By contrast, the engine was not included in the table of model diesel engines for the years 1948-51 which was compiled in 1951 by Ron Warring for Model Aircraft We know that Warring was certainly aware of the Milford Mite, since the engine was included in the listing of British engines which appeared in Warring's 1949 book Miniature Aero Motors. However, the engine was listed in that work as being no longer in production and there's no comment about it in the main text. This is certainly consistent with the idea that production ended in 1948.
It's interesting to note that Warring gives the conrod material for the Milford Mite as being aluminium rather than the actual steel and also gives slightly different bore and displacement figures for the Mk II and Mk III versions of the Milford Mite. Odd, because the manufacturers made no such distinctions in their advertising! Even more strangely, Warring assigns a larger bore of 0.4657". to the Mk III Mite (as opposed to the cited 0.4625 for the Mk II) but gives a smaller displacement to the Mk III! Despite quoting identical stroke measurements! In addition, Warring fails to mention the ball race shaft, citing the bearing as merely a plain bushing. It appears that he may have going on the basis of somewhat inaccurate second-hand information and did not check his sums all that closely!
Further confirmation of our postulated dating is to be found in the late Vic Smeed's very informative 1986 compilation "Fifty Years of Aeromodeller". On page 34, the author notes that by Spring of 1947 there were no fewer than 14 British-made engines on the market and that by early 1948 this number had doubled. The Milford Mite is specifically included in Smeed's listing of these engines, along with a comment that a number of British-made engines of the period were offered for sale for "only a few weeks before fading away". Based on the manufacturer's advertising researched by Kevin Richards, the Mite actually did a little better than that!
It seems rather odd that the makers of the Milford Mite were not concerned regarding any possible confusion between their offering and the better-known and (it must be said) far better-finished 0.73 cc Majesco Mite which was on sale at the same time. There has in fact been some later confusion between the two contemporary British "Mites" (to confuse things even more, there was also a contemporary American-made Mite diesel of completely different design!). Just to set the record straight, the Majesco Mite was designed by a gentleman named S Colyer, who was a friend of Colonel Bowden and an associate of Ron Warring. Indeed, Warring was closely involved with Colyer in the design and production of the Majesco Mite, as recorded in his 1949 book cited previously.
An illustration of Colyer holding his own model and that of Colonel Bowden appears on page 132 of Colonel Bowden's first edition. The accompanying text makes it quite clear that both models are powered by the 0.73 cc Majesco Mite, for which Colyer is given the design credit by Col. Bowden. Indeed, on page 63 of Colonel Bowden's first edition, Colyer is actually named as the maker of the Majesco Mite. Hence there appears to be no possible connection between Colyer and the Milford Mite now under discussion.
As stated earlier, the Milford Mite was an essentially conventional side-port design of its era, but it did display a number of rather unique features which set it apart from the rest. The basic design never changed, but certain details of the engine's construction were amended as time went by. Let's have a quick look at these amendments.
As far as is known, none of the Mite variants were ever assigned serial numbers. Accordingly, we have to deal with them strictly on the basis of the known Mark numbers assigned by the manufacturers.
The earliest known variant must surely be the one that appears as figure 40 on page 51 of Colonel Bowden's first edition mentioned earlier as well as in Laidlaw-Dickson's 1947 second edition. By reverse extrapolation from the manufacturer's advertising, it appears that this must have been what the makers called the Mk I Milford Mite.
I have been unable to locate either an example of this seemingly very rare variant, nor any other references to it, so it appears that this must have been a short-lived initial version which was quickly amended for whatever reason. Our apologies for the poor quality of the attached images scanned from the two books mentioned, but as these are the sole images of this variant of which we are presently aware, we're stuck with them!
The engine had evidently only just been announced when Col. Bowden was finalizing the first edition of his book, since no details appear to have been forthcoming and there is accordingly no description of the engine in the text. One suspects that the illustration was inserted at the last minute after the text had already been completed, more or less as an afterthought to ensure completeness of coverage.
This impression is heightened by the fact that Colonel Bowden actually seems to have been poorly informed about this engine, citing its displacement as 1 cc instead of the actual figure of 1.41 cc. Mind you, he was not alone in assigning this displacement to the Mite—a December 1947 advertisement placed in Aeromodeller by the Hull Model Shops offers the "Milford Mite 1 cc" diesel at the £4 figure mentioned earlier, and this was at a time when the makers were advertising the 1.41 cc Mk II Mite directly above the Hull Model Shops advert in the same issue and at the same price direct from the makers! Presumably dealers received a wholesale discount in order to give them a workable profit margin.
Oddly enough, Laidlaw-Dickson (writing at roughly the same time as Colonel Bowden about the same model) got the displacement correct—he quoted it as 1.41 cc. There seems little doubt that this was the engine's displacement all along and that the figure quoted by Colonel Bowden and repeated by the Hull Model Shops was in error.
The caption to Colonel Bowden's illustration mentions the use of a stop in the fuel filler cap to control the duration of the run, but that was as far as he was able to go. The associated image doesn't make this device clear, so we'll discuss this feature in detail when considering the Mk II version below.
This initial version of the engine is distinguished from its successors mainly by the design of its cylinder jacket. Based on the illustrations, it is apparent that the cylinder liner was contained inside a full-length cast and machined upper cylinder unit which incorporated the exhaust stacks, the carburettor boss and a series of closely-spaced cooling fins of circular form along with the bypass passage (visible at the front) and the cylinder head with its tapped hole for the compression screw. Quite a complex piece of casting! Like all the other cast components used in this design, it appears to have been produced by sand-casting.
The liner was presumably inserted into the upper cylinder jacket from below, and the complete unit was then attached to the main crankcase casting by four relatively short screws which bore upon the corners of a flange of square plan view which formed the base of the cylinder jacket casting.
The induction tube appears to have been cast integrally with the main upper cylinder jacket. It seems to be either screwed in or pressed in—only a direct examination would settle this point. The needle was an externally-threaded item which screwed into an integrally-cast boss in the usual way.
The tank was of a most interesting design, being formed as part of a single casting of unusual complexity which doubled as the backplate. This unit was attached to the crankcase from the rear by two screws, and the fuel pickup tube extended downwards from the carburettor into a vertical cylinder which opened into the base of the tank and was cast in unit with the tank and backplate. The tank itself was of cylindrical form and was most unusually angled backwards. It was internally threaded and had a screw-in full diameter plug at its open end with a vent for filling. More of this below...
Unlike Colonel Bowden's first edition, Laidlaw-Dickson's 1947 second edition includes a comment in the main text in addition to the illustration reproduced above. The writer made a few statements which actually have great relevance to this discussion. Since this is the closest thing that we possess to a "review" of the engine, it seems worth quoting in full:
"On practical considerations we must mention the Milford Mite—another newcomer of 1.41 cc. This engine on first sight fails to impress. It lacks those qualities of high grade finish that other manufacturers have concentrated upon. The intended buyer should not be misled by this apparent roughness however. It is what goes on inside that must be the final test. Here will be found that high degree of compression and absence of play so necessary in a small engine. In addition the manufacturers invite buyers to test their own engines in their workshops before taking them away, and what can be fairer than "try before you buy"".
In summary, Laidlaw-Dickson was saying that what the engine lacked in immediate eye appeal was more than compensated for by the quality of its internal fitting and finish. He also commented upon the evident confidence in their product which was displayed by the manufacturers. Both comments appear to fly directly in the face of the long-standing legend of the Mite's shortcomings!
Regardless, this version of the engine does not seem to have survived in production for very long—as previously mentioned, by July 1947 the makers were already advertising the Mk II version of the Mite to be described next. It may be inferred from this that the Mk I Mite remained in production for only a few months at most.
The Mk II Milford Mite (which Mike Clanford incorrectly calls the Mk I) retains the same general design layout as well as the same bore and stroke as its predecessor, but exhibits some significant design changes to the upper cylinder jacket. The exhaust stacks and carburettor mounting remain unchanged, but the former circular cooling fins are gone—indeed, the revised jacket is far less well provided with cooling fins. Presumably experience had shown that cooling was not a problem with this design when used in its intended sport free-fight application with associated short runs.
The sole residual concession to engine cooling was the provision of only three shallow and rather thick integrally-cast cooling fins at the top having a square plan view as opposed to the former circular shape. These fins added very little to the available cooling area and seem to have been included more because the customers would expect to see cooling fins than for any other reason! However, advantage was taken of the four "corners" of the square-section fins to replace the former short cylinder attachment screws at the base with far longer studs passing from the cylinder head through the corners of the three cooling fins and on down through holes in the base flange into the same tapped holes in the main crankcase casting that had been formerly used. These studs were exposed for much of their length. They were topped with matching nuts.
The only other change worth noting is the addition of the word "MITE" stamped onto the left-hand side of the upper cylinder base flange. The fuel supply arrangements continued unchanged in this second variant, as did the main crankcase casting. Indeed, apart from the revised upper cylinder jacket and method of fastening this variant appears to be more or less identical to that which appeared in Colonel Bowden's book.
One thing which will be clarified by reference to the attached image is the fuel tank timing device mentioned by Colonel Bowden in connection with the Mk I version of the Mite. This device seems to have been carried over directly from the Mk I to the Mk II. It consisted of a threaded plug which screwed into the tapped interior of the cylindrical fuel tank and had a filler hole at its centre. By screwing this more or less into the tank, one could in effect vary the tank's fuel capacity and hence the approximate length of the expected motor run. I can't personally recall another instance of the provision of a fuel tank of variable capacity—ingenious, if a little imprecise!
The carburettor body on the Mk II Mite is cast integrally with the upper cylinder casting. It seems very likely that this was a continuation of the approach applied to the manufacture of the Mk I model described earlier. The intake tract has a true venturi profile, the measured diameter at the throat being a mere 0.120".
Perhaps the greatest disadvantage presented by the use of this very individualistic type of tank was the fact that the design rendered it quite impossible to used the engine with any alternative fuel supply arrangements. The very small tank capacity clearly restricted the engine to free flight applications, and removal of the standard tank to connect the engine to an alternative tank also involved removal of the backplate! Hence it was impossible to provide any form of alternative tank for this engine as supplied.
Not only that, but the engine could only be mounted in the upright position - the tank would not hold fuel in any other orientation. At the time, inverted mounting was very popular among free flight modellers and sidewinder mounting had become widely employed in control line designs. It would be completely understandable if the limitations imposed by this tank design had acted as a major sales deterrent. The only available fix for this problem would have been the provision of an alternative tankless backplate, but we currently have no evidence that such an accessory was ever offered.
A tentative attempt to dismantle my example of the Mite Mk II proved futile, since the cylinder assembly proved to be mated to the lower crankcase unit "for keeps" and I was not willing to force matters given the engine's excellent condition. Removal of the backplate is not possible without prior cylinder removal, and hence I am unable to go further in my description of the Milford Mite Mk II.
The previously-mentioned advertisement from the December 1947 issue of "Aeromodeller" which appeared directly above the Hull Model Shops placement confirms that this version of the Mite was still in production as of December 1947. The copywriter was evidently the elusive Mr Smith, who certainly had a chatty and amusing style! It seems that his wife had been writing some of the advertising copy but had decided that it was his turn and that he should impart some useful technical information. Nothing loath, Mr Smith proceeded to demonstrate in most amusing terms the fact that the Mite produced an output of 6 MP (Mouse Power)!! I think that I would have got along with this chap, preferably over a pint or two
The third and final variant of the Milford Mite which has come to our attention is the Mk III, which Clanford incorrectly designates the Mk II. In this final variant (as far as we are aware), all of the main castings have been completely changed (requiring that new patterns be made) and the fuel system has been substantially updated.
There's no doubt at all that this version of the engine was in production as of April 1948, since an advertisement was placed in "Aeromodeller" for that month. In this advertisement, the makers cite recent overseas shipments to such exotic locations as Australia, the USA, Malaya, South Africa, India and even Malta! The copywriter (presumably the effervescent Mr Smith) once again reveals his chatty style and strong sense of humour by printing an amusing letter ostensibly from a dealer which complains that the Mite is "too square" and is scaring off potential customers because of this!! The text is revealing in that it cites the reason for the minimal cooling provisions on the Mite as being the need to avoid over-cooling in the British climate! There may in fact be something in all of this!
A further advertisement for the Mite Mk III appeared in the June 1948 issue of Aeromodeller. The style of this placement was quite different, however. It seems that things had got a little serious for the manufacturers by this time. For one thing, Mr. Smith had apparently exhausted his sense of humour and did not include any of his witty comments as he had done previously. The advertisement was strictly business in nature.
The price of the Mite Mk II was unchanged at £4 4s 0d, but for the first time, the engine was now available on the hire purchase scheme. A down payment of £1 10s 0d allowed the customer to take possession of his engine and he was then required to make twenty weekly payments of a princely 3s 0d to complete the purchase. Thus the customer ended up paying a total of £4 10s 0d under this scheme—a credit premium of 6s 0d over the twenty week period. This translates into an interest rate of 6.66% payable for the period, or around 17% per annum. Nice work if you can get it!
The makers were now offering a fully machined set of castings needing only assembly and running-in for £3 3s 0d—the un-machined castings were no longer on offer. Most interestingly, the company was offering reconditioned Mk IIís, fully guaranteed for only ££3 0s 0d. In other words, they were undercutting their own Mk III model! From new design to "reconditioned special" in only a year strongly suggests that a lot of Mk IIís had been returned as unusable and had had to be "reconditioned" to render them serviceable. It must in fact have seemed increasingly pointless to continue making the Mk III when there were so many rejected Mk IIís going cheap.
At least we are now dealing with a variant for which an accurate and detailed contemporary description can be provided, since one of my own examples of the engine is of this type and was able to be pulled apart for inspection. As a comparison of the various images will confirm, this variant displays a wide range of design departures from its two predecessors. The crankcase casting is completely different, the upper cylinder casting has been eliminated altogether and the carburettor and fuel tank arrangements have been completely revised.
Let's have a close look at an actual example of this version of the Mite.
The Mk III Mite—Detailed Description
It appears that the changes in evidence on the Mk III Milford Mite to be described next were made at least in part to cut down on the amount of casting involved. The design revisions resulted in the elimination of two relatively massive and complex castings in favour of a pair of far simpler and smaller castings.
For starters, the crankcase casting was substantially revised. It now extended up above the exhaust location and included both the exhaust passages and the carburettor mounting which had formerly been part of the upper cylinder jacket casting. The former stubby exhaust stacks were eliminated in favour of a simple pair of slots. As before, a single bypass passage was formed at the front of the casting in the conventional location for a sideport engine. The casting was apparently finished by brushing.
Although still pretty massive, the crankcase casting was somewhat more "streamlined" and compact than that of its predecessor and was externally contoured to make provision for the inclusion of some internal machining to allow for con-rod clearance. More of this below.
One good feature of all models of the Mite was continued in the new design. This was the use of mounting lugs of very substantial length, with a relatively wide longitudinal mounting hole spacing. The lugs and mounting holes were centred slightly forward of the cylinder axis, more or less on the engine's centre of mass. The design was such that a solid mounting was more or less assured. One slightly unusual feature was the fact that the lugs were centred upon the axial centre line of the crankshaft, leaving the shaft centre line a little above the plane of the mounting surfaces. All of these arrangements were later to re-appear in the Elfin 1.49 and 1.8 BR models.
There was however a fly in the above ointment which applied to all variants of the Mite. The rear of the mounting lugs had to accommodate the tapped holes for the two screws that retained the backplate. The designer elected to create a slight expansion of the lug thickness at the rear. While this increased its thickness over that of the Mk II model, it was still rather marginal for tapping. This would have been a good idea were it not for the fact that the lower portions of the thickened sections naturally extended below the plane of the mounting surfaces and required that the bearers be slightly recessed to accommodate the twin "bulges".
And it doesn't stop there—the two lugs cast into the sides of the backplate to accept the retaining screws on each side were made somewhat oversize, presumably to reduce the possibility of their opening up under stress. Again, not a bad idea, but the consequence was that the lower edges of the backplate lugs once again extended well into the plane of the bearer surfaces, and the bearers had to be notched to accommodate this anomaly. Annoying!
The main bearing appears to be unchanged from the earlier variants. The single ball race at the rear was carried over to the new model. At the front end, the plain bearing section has a nominal as-cast external diameter of 0.500". and is equipped with a thick-walled bronze bushing in which the 0.250" dia. crankshaft journal runs. This bushing has an O/D of 0.391" (nominally 25/64"), which means that there's actually not a lot of cast metal left around the bushing itself. Given the fact that the main bearing of this variant is not equipped with reinforcing gussets, it would appear at first sight that the design is a bit anaemic in terms of crash-resistance at the point where the main bearing meets the front of the crankcase casting—some stiffening gussets might have been a good addition. Indeed, vestigial gussets had been a feature of the earlier versions of the Mite.
The manufacturers appear to have been aware of this issue, and in the revised model the reduction in diameter from the ball race housing down to the front bearing "stub" was moved forward in the new design to coincide with the forward ends of the mounting lugs. The result of this change would have been a substantial increase in the thickness of the front wall of the crankcase itself. Combined with the facts that the relatively thick-walled bushing itself doubtless added greatly to the strength of the bearing and the rear of the shaft was of course very well supported by the ball race and the strengthened crankcase casting, this was likely an adequate response to the strength issue.
So much for the revised crankcase. Turning now to the steel cylinder, this is a simple tubular item which is equipped with a conventional locating flange immediately above exhaust port level. The flange is squared off at the sides and rear to match the case but is left in its turned configuration at the front, matching the curved contour of the main casting at that point. The corners of the flange are drilled through to allow the passage of the four long cylinder hold-down screws which replaced the former studs on this variant.
Another very significant change is the form of cylinder jacket used. The full-length cast jacket has been replaced by a far shorter machined jacket located at the top of the cylinder, leaving most of the working length of the cylinder exposed with no cooling provisions, exactly as in the contemporary E.D. Comp Special and Mk III models. The three rather minimal fins are retained and slightly thickened in the revised jacket, but the component is now a simple turning from square bar stock (or perhaps a square turning and milling from round bar stock) rather than a casting. The compression screw appears identical to that used in both of the previous variants.
The revised cooling jacket is retained in place by four long hold-down screws which replaced the studs used on the previous model. These screws pass through holes drilled in the corners of the squared-off fins and pass externally down the cylinder and through the corners of the cylinder flange to engage with four tapped holes in the crankcase. Hence they retain both the cooling jacket and the cylinder itself. The screws are fully exposed for a substantial proportion of their length.
At the rear, things are very different again. An entirely new carburettor casting is employed which includes a very substantial integrally-cast tank top. This unit is attached to the rear of the main crankcase casting by two screws which pass through the outer corners of an integrally-cast flange to engage with tapped holes in the flat carburettor mounting surface at the rear of the upper crankcase. This arrangement replaces the cast construction formerly used.
A conventional moulded plastic tank is mounted beneath the cast tank top and is retained at the sides by a pair of screws with washers having flats filed on one side. These function as wedges to hold the tank in place. The arrangement seems a little sketchy at first glance, but in fact the tank stays put in use with no problems. Unusually by the standards of the day, there is no provision for a fuel cut-off on this model.
This tank arrangement had several significant advantages over that used in the previous model. For one thing, it had a far more practical fuel capacity. In addition, the revised carburettor assembly could be removed, rotated axially 180 degrees and remounted in an orientation suitable for inverted mounting of the engine. Moreover, the standard tank could be dispensed with altogether and the engine supplied from any tank of the owner's choosing. This meant that the standard hang tank could be used with the engine either upright or inverted and sidewinder mounting was also perfectly possible provided suitable alternative fuel supply arrangements could be made. This one change made the revised model far more flexible in terms of potential applications.
The tubular main jet is made of copper and screws into the underside of the casting. It doubles as the fuel pickup line. The externally-threaded needle appears unchanged from that used previously. It screws into a boss on the upper side of the casting and is tensioned with a coil spring. The screw-in main jet stops at the wall of the venturi opposite the needle, and the unit thus operates on the surface-jet principle which was then very popular in England and elsewhere.
The backplate is a very much more compact casting than its predecessor since it no longer incorporates the fuel tank. It is a simple un-recessed (and hence quite heavy) casting which is machined at the front to fit the rear of the crankcase. A gasket is used to seal. As mentioned earlier, the backplate is attached to the rear of the crankcase using a pair of screws which pass through the two hold-down lugs at the sides to engage with tapped holes in the mounting lugs, which are slightly expanded at those points.
Finally, the prop mounting arrangements appear unchanged from the earlier variants. The steel prop driver has a square opening at the centre which locates onto a square section machined into the shaft just forward of the main bearing. The assembly is completed by a neatly-made spinner nut turned from hexagonal bar stock.
An interesting feature is the complete absence of any form of serrations or knurling on the driving face of the prop driver. This was a not-uncommon approach at the time, and in fact prop slippage is not a problem with this engine in my direct experience. The arrangement actually has an advantage in that it allows for some prop slippage during a hydraulic lock or crash impact, which could be beneficial in protecting the crankshaft or other components from breakage. Some examples are seen with a pair of driving pins set into the face of the driver, but these may possibly be an owner modification.
So much for what can be learned from an external examination! I'm always a bit reluctant to start pulling apart the older and rarer engines in my collection unless repairs are needed (which they weren't in this instance). In the case of the Mite, I decided that I would be prepared to remove the carburettor and backplate for inspection and photographic purposes. However, I did not wish to disturb the working components in any way given that they were already well "acquainted" and needed no attention.
So off came the entire tank assembly, followed by the backplate. Both of these items are secured by 6 BA screws and were thus easily removed. These actions were sufficient to reveal the main features of interest in this design. As it turned out, there are one or two such features!
For starters, the crankshaft proved to be a built-up item consisting of a separate crankweb of plain disc form (no counterbalance) which is mated to the nominally 1/4" diameter shaft. Kevin Richards was kind enough to take his Mk III example apart a bit further, and this revealed that the shaft is actually made up of three separate components—main shaft, crank-disc and crankpin. The crankpin is pressed into a hole in the crank disc, which is made very thick to provide good support. The crank-disc is retained in position on the main shaft by means of a transverse pin installed in a cross-drilled hole passing through both components.
This form of composite construction was by no means unique—the British Nordec 10 cc racing engines also employed a built-up shaft and the latter-day PAW engines (among others) use pressed-in crankpins. The advantage was a certain simplification of the machining processes involved as well as the avoidance of the stress concentrations created at the junction points of shafts and crankpins machined in unit with the crankweb.
The single ball race is located in a machined recess in the crankcase just forward of the crankweb. It provides excellent radial support for the shaft at that critical point. As mentioned earlier, the forward end of the crankshaft is carried in a bronze bushing which is pressed into the main casting in the usual way.
The con-rod is made of steel and the component in my example appears to have been hand-filed from a piece of flat plate! It is undeniably a bit on the crude side by comparison with the work produced by other contemporary British manufacturers. However, it appears perfectly adequate for the job, and one does not have to look at it while using the engine!
Again, Kevin was able to supply an image of the piston-rod assembly from his example, and this shows that the rod in that instance is somewhat roughly turned rather than hand-filed. Perhaps one or the other is a home-built example?? Impossible to say which is which, if so!
The reason for the angled "columns" cast externally into the crankcase casting at the sides above the mounting lugs becomes apparent immediately upon looking inside the crankcase—in order to provide clearance for the con rod it was necessary to form two angled channels in the crankcase interior at the sides. This appears to have been done by milling.
The engine is quite conventionally ported along very similar lines to the contemporary ED Mk II and Comp Special models. Exhaust porting consists of a pair of milled rectangular openings which feed into exhaust slots formed in the sides of the crankcase casting. A single transfer port of elongated oval shape is supplied with mixture through the front bypass passage mentioned previously. This bypass passage is quite large and has been produced by milling. The actual transfer port is located quite low in the cylinder wall, necessitating the use of a step in the piston crown, exactly as in the two ED models mentioned above as well as the competing Mills diesels.
The piston is machined from cast iron and is of fairly massive proportions. It has cutaways in the skirt fore and aft. The front cutaway greatly improves gas access to the bypass passage and is a feature that E.D. would have done well to copy on their 2 cc models—it is a commonly -encountered and extremely effective modification on those engines. The rear cutaway serves no functional purpose apart perhaps from balancing (and lightening) the piston—it merely dictates the vertical positioning of the induction port.
In defiance of the Mite's reputation, the piston fit in my Mk III example is beyond reproach—compression seal is outstanding, yet there is no trace of stickiness anywhere. The contra piston is equally well fitted—in fact, if anything it's a touch on the tight side. It is of course possible that the engine has been rebored at some point, but there's no actual evidence for this. Indeed, the engine gives the overall appearance of having had relatively little use, although it has clearly seen some service. I'd expect a rebored engine to look a little more "beaten up".
Turning to the fuel supply side, the induction port in the cylinder wall is similar in shape to the transfer port and has a relatively generous area. Indeed, as an overall comment it's fair to say that the porting arrangements in the Mite appear throughout to be more than adequate for the job. The induction port is supplied with mixture through a 0.147" diameter round hole drilled through the flat surface provided at the rear for mounting the carburettor assembly. Two tapped holes are provided in this surface at the sides to accept the screws which retain the assembly. A paper gasket is used to seal. There is no supplementary sub-piston induction.
One possible point which could affect consistency should be mentioned here. There is no positive provision for the accurate location of the carburettor assembly on the mounting surface described above. The two screws are the sole means of locating the unit, and they provide no guarantee of correct alignment between the venturi tube and the opening at the rear of the crankcase. The holes in the mounting flange are a sufficiently loose fit that the unit has slight lateral freedom of movement prior to being fully tightened. For best performance, it's necessary to inspect the alignment through the open end of the venturi to ensure that the unit is more or less correctly located.
We described the carburettor casting and the fuel tank arrangements earlier. When we examine the actual venturi with the assembly removed, we find some evidence that the maker(s) of this engine knew at least a little about what they were doing! The induction tube has a genuine venturi shape, with a sharper opening angle beyond the point of fuel input than the closing angle prior to that point. The tube tapers steadily from a generous 0.232 in dia. opening at the rear to a throat diameter of only 0.116", fractionally smaller than the corresponding diameter in the Mk II Mite, although this is probably incidental. The throat section at the needle location is parallel, and immediately beyond this point the tube opens out quite sharply to a diameter of 0.147". to match the hole in the rear of the crankcase. In other words, a true venturi which should (and does!) promote quite good suction.
The fuel pickup tube, unusually made of plain 1/8 in OD copper tubing, is externally threaded at the upper end and screws into the central boss on the underside of the venturi casting opposite the needle boss. The pickup tube is installed as-is with respect to its internal diameter, no attempt having been made to provide a smaller jet orifice for better fuel atomization. This requires the use of a needle tip of unusual thickness. The needle is a more or less conventional externally threaded item which is effectively held at its setting by a light coil spring. Its one unusual feature is that the needle control and the needle itself are turned integrally from a single piece of brass, rather than having a steel needle inserted in the more customary fashion.
All in all, the Mite proves upon examination to be a perfectly conventional sideport diesel of its period, albeit one with a certain quirkiness in terms of its appearance and construction which give it a character all its own!
The Quality Issue
There's seldom any smoke without at least a little fire, and it's pretty clear from the various comments recorded down through the years that many examples of the Milford Mite must have fallen well short of the standards expected from British model engine manufacturers by 1947/48. Indeed, it's perfectly possible that one reason for the relative scarcity of surviving examples could be that many of them went straight into the rubbish bin after their owners gave up on them in disgust!! Some of these may of course have been sub-standard attempts by home constructors to make an engine from the casting sets supplied to order.
Having made the above statement, I'm now going to start sounding like a bit of a heretic by flying in the face of legend—I have to say that my own example of the Milford Mite is actually quite well made, especially where it really counts! I commented earlier that the piston fit in my engine is notable for the excellent compression seal combined with a virtual absence of any "stickiness" at any point in the stroke. The contra piston is equally well fitted. Crankcase compression too is first rate. There is a little slop in the rod bearings, but the engine has undoubtedly been mounted and used (Wot?!? A Mite getting used?!?) and the small amount of detectable play is consistent with incidental wear arising from normal operation.
Following the original publication of this article, I was fortunate enough to acquire the illustrated example of the Milford Mite Mk II from my friend Mel Reid, and this example proved on direct examination to be just as well fitted throughout, albeit having seen somewhat more use. It is as roughly finished externally as its later companion, but seems to be very well put together internally, where it really counts. It started and ran very well indeed on initial bench testing.
If they were all as well made as these examples, I'd say that the engine scarcely deserves the almost universal opprobrium that has been heaped upon it over the years! However, I'm personally able to comment on this issue on the basis of two examples, and it's certainly true that one cannot draw any general conclusions on such a basis.
Even so, it actually appears that my engines are not unique and that there were at least some other examples that were well enough fitted to run OK. Mike Clanford claimed on page 130 of his A-Z book that his example of the Mk II Milford Mite ran "well" (but see below). Fisher too made the general statement that the engines "would run". As we shall see, my own examples go one better than that—they run well enough to fly a model quite effectively. Indeed, they both appear to have done so at some point!
I initially thought that the existence of my own and Clanford's fully functional examples of the Mk II Mite constituted proof positive that there were at least two serviceable examples on record. However, a tracing of its ownership history has confirmed that the Mk II Mite which I now own is the actual engine illustrated in Clanford's book! It had been purchased from Clanford by another collector and was subsequently acquired from the latter by none other than my mate Kevin Richards! From there, it passed into the hands of Mel Reid and thence to me. Apart from the confirmed ownership history, a number of clearly visible markings as well as the imperfections in the strike of the "MITE" identification on the crankcase put the engine's individual identity beyond doubt.
So the two running examples that I thought I could report turn out to be one and the same engine! To offset this, Kevin reports that although he never ran this example while it was in his possession, he did own another example of the Mk II Milford Mite about 5 years ago which ran "very well indeed" (to use Kevin's own words). So the count of known operable examples of the Mk II Mite remains at two!
It thus seems certain that least some examples of this much-maligned engine were sufficiently well made to have potentially given good service. That said, the sorry reputation of the Mite and its very short production period combine to suggest that many examples did not come up to the required standard. There must surely be some basis for the long-standing legend of the Mite's shortcomings!
I confess to a sneaking suspicion that many of the really bad examples of the Mite were the products of home constructors for whom the task proved too much. In all probability most of these did indeed end up in the rubbish bin, leaving only their sorry legend behind them.
It is also perfectly possible that some of the factory-made engines also came up short in the quality department, although this appears to be directly contradicted by the manufacturer's standing invitation for customers to visit their workshops to see their engines tested before taking delivery. A high level of confidence in the product is implied here. Laidlaw-Dickson noted this and also suggested that the factory-made engines were quite well-made where it really counted.
Regardless, if the company was in the habit of producing sub-standard engines, most of those examples probably joined their home-built counterparts in the rubbish bin! This would explain very well a) why so few examples survive today and b) why a good proportion of the few that do survive appear to be well capable of giving good service—only the best escaped the rubbish tip!! In other words, the average quality of the surviving examples may be considerably better than the overall average at the time of manufacture, whether by the company or by their customers.
Even so, it must be admitted that even on my seemingly better-than-average examples the castings are rather crudely executed. Indeed, the main bearing on my Mk III Mite actually has a casting flaw near the front which extends right into the main bearing sleeve and thus looks like a hole! In addition, the shaft in my Mk III engine is rather a sloppy fit in the bronze bushing, although certainly not enough to worry about unduly. The hand-filed con-rod is definitely a touch on the crude side too, although it does appear perfectly adequate for the job.
It's not unfair to say that even a good example of the Mite (which both of mine are) shows evidence of its essentially artisan origins in the form of some rather cobbly execution of certain aspects of the design. However, my examples at least are quite well executed where it really counts, i.e., in the piston/cylinder assembly, which is the heart of any model diesel. they're certainly sufficiently well made to run very well indeed and to fly a model quite satisfactorily.
Having said this, I must admit that appearances can be deceptive and the old saying about the proof of the pudding definitely holds good here; how do the things actually run? Only one way to find out and that's to run 'em.
The Mite On Test
My example of the Mk III Mite has clearly had a bit of use in its time, although as stated above it remains very well fitted where it counts. This being the case, there was clearly no need for me to plan on doing any running-in of the engine prior to testing its performance on my usual set of test props. This was all to the good since I wanted to minimize the running time involved and the attendant risk of deterioration or damage.
In order to provide some kind of context to the engine's measured performance, I also tested a Mk I Series 2 Mills 1.3 at the same testing session using the same props and fuel. As noted earlier, this is a fair comparison because the two engines are very similar in displacement and were in production during more or less the same period.
In view of the Mite's displacement, design configuration and reputation, I was not expecting much in the way of high-speed performance. Accordingly, I elected to begin with a 9x4 prop just to see how the land lay. I guessed the needle setting, left the compression as set, filled the tank, gave it two choked flicks and was ready for the off.
The engine made an excellent initial impression by starting on the third flick following choking! I'd set the needle a little rich, but it burbled away quite happily, waiting for me to set it correctly. Once set, it ran with surprising vigour and seemed to swing the fairly large prop at a good rate.
Greatly encouraged, I proceeded to test a series of props that should in theory cover the available speed range. Starting remained foolproof at all times, no prime being required. In deference to its age and rarity I didn't press the engine unduly, keeping it very slightly rich and under-compressed. Even so the results achieved were by no means unflattering to the little Mite:
|10x4||Taipan GF nylon||6,400 rpm (0.062 bhp)†|
|9x6||Taipan GF nylon||6,300 rpm (0.059 bhp)|
|9x4||Taipan GF nylon||7,300 rpm (0.070 bhp)|
|8x6||Taipan GF nylon||7,100 rpm (0.065 bhp)|
|8x4||Taipan GF nylon||8,600 rpm (0.061 bhp)|
† Based on the Cornell power absorbtion figures
The tentative bhp figures given above are based on power absorption coefficients for my test set of Taipan props which were extrapolated from those provided by Gordon Cornell for the APC series on the basis of comparative testing. They give results which are extremely consistent with those derived from the APC series.
It's clear that the power is still climbing at 7,300 rpm but has begun to fall again as of 8,600 rpm. The peak therefore lies somewhere in between. Given the usual fairly steep decline past the peak with sideport engines, a power peak of around 0.076 at around 8,000 rpm is implied by these figures, which could almost certainly be bettered by more precise setting of the controls. Really not a bad performance at all considering the Mite's sorry reputation! Running remains smooth and absolutely miss-free at all speeds tested, with no tendency to "sag".
It will be noted from the July 1947 advertisement mentioned earlier that the makers only claimed a speed of 7,000 rpm for the Mk II version, and also specified a 9x6 prop. On the basis of the above test, there's little doubt that the engine would get a 9x6 up to the claimed 7,000 rpm in flight, but the figures suggest that the Mk III version may in fact have given its best performance at a slightly higher speed.
One thing that I found quite impressive was the general "feel" of the engine. Thanks to a combination of the ball race and the excellent piston fit, the engine has a really "silky" feel about it when turned over. It actually feels like a far more sophisticated product than its reputation would lead one to expect.
I then tested the Mills 1.3 Mk I Series 2 on the same props using the same fuel. This example has been used a little and is nicely freed up. It should therefore be more or less at its peak of condition. Despite this, it was unable to match the Milford Mite on any prop tested—indeed, it didn't come close! The figures obtained were as follows:
|10x4||Taipan GF nylon||5,600 rpm|
|9x6||Taipan GF nylon||5,400 rpm|
|9x4||Taipan GF nylon||6,300 rpm|
|8x6||Taipan GF nylon||6,100 rpm|
|8x4||Taipan GF nylon||7,300 rpm|
These findings came as a total shock to me—solely on the basis of the respective reputations of the two engines, I had been expecting the Mills to bury the Mite despite its .11 cc displacement disadvantage! Note too that the gap becomes steadily wider as speed increases. The Mills is clearly done by around 7,000 rpm (admittedly as advertised), whereas the Mite is still going strong at 8,000 rpm. Setting aside the fact that the Mills is unquestionably a better-made engine overall, a practical modeller offered the choice of these two engines strictly on the basis of performance would opt for the Milford, no question. Heretical, or what?
One clue as to the superior performance of the Mite comes from the fuel consumption. To make power you have to burn fuel, and the Mite goes through quite a lot of fuel for its size. The tank is admittedly quite small, but I was expecting more than the 1 minute 15 seconds run time (including warm-up) that I got. This is perfectly adequate for a sport free-flight model, of course, but the engine does seem to burn quite a healthy dose of fuel for its size. Perhaps that's where the power comes from. By contrast, the Mills runs forever on its admittedly somewhat larger tank.
The Mite survived its test session with flying colours, no problems at all being experienced throughout. All in all, a convincing testimonial to the fact that a good example of the Mite was an entirely satisfactory engine with a better-than-average performance by the standards of its day. Heresy indeed!
Having been fortunate enough to subsequently acquire the ex-Clanford Mk II Milford Mite as mentioned earlier, I was able to subject this model to a repeat of my earlier tests using the exact same airscrews from my test set plus a couple of the APC series as well as a 9x4 Top Flite wood prop. To ensure consistency and allow for atmospheric and fuel variations, I also spot-checked my Mk III Mite at the same time and on the same fuel batch.
The Mk III Mite proved to be just as well-mannered as it had been on its original test. It turned the 9x4 and 8x4 Taipan props within 100 rpm of its previous figures, indicating good comparability of results between this and the earlier tests.
The Mk II Mite proved a little trickier to start, mainly due to a rather sensitive needle valve combined with the fact that a prime was more or less essential - choking alone didn't do the trick. It was also somewhat more worn than its companion, and I found that the piston seal when lubricated with liquid fuel was less than perfect, although still sufficient for starting purposes. A drop of oil injected into the cylinder created a better seal and greatly improved starting. Using this technique, the Mk II showed itself to be just as responsive as the Mk III, starting with a few flicks every time. The engine could be started with the needle left at its running setting, but I found it necessary to reduce compression slightly once a start had been achieved.
As noted earlier, the needle valve on the Mk II proved to be far more sensitive than that of the Mk III in terms of the optimum setting. Another issue was the large variation in fuel head as the level in the unusually deep tank went down. The engine had to be set a little rich when starting on a full tank in order to have it "come in" to an optimum mixture setting towards the end of the run.
These tests highlighted the previously-discussed limitation imposed by the very small tank capacity. Even with the tank plug out to its limit, a full tank only gave a 35 second run, including warm-up. This is of course adequate for sport free-flight purposes, but only just. It would pretty much be a matter of start-and-launch!
Despite these issues, the Mk II Mite proved to be a very smooth runner with a perfectly useable performance. It failed to match the figures obtained for the Mk III Mite, but not by an unduly large margin until speeds passed the 7,000 rpm mark. It still handily beat the figures obtained previously for the Mills 1.3 Mk I Series 2.
For convenience in making a direct comparison, I've shown the figures obtained previously for the Mk III Mite in brackets alongside those for the Mk II version. I've also shown the implied horsepower readings for the Mk II Mite. The results were as follows:
|10x4 Taipan GF nylon||6,000 rpm (6,400) 0.055 BHP|
|9x6 Taipan GF nylon||5,900 rpm (6,300) 0.052 BHP|
|9x4 Taipan GF nylon||7,100 rpm (7,300) 0.064 BHP|
|9x4 APC GF nylon||7,000 rpm (not tested) 0.064 BHP|
|8x6 Taipan GF nylon||6,800 rpm (7,100) 0.057 BHP|
|8x4 Taipan GF nylon||7,900 rpm (8,600) 0.051 BHP|
|8x4 APC GF nylon||7,800 rpm (not tested) 0.051 BHP|
|9x4 TF wood||6,800 rpm (not tested) 0.061 BHP|
Despite a few anomalies due in all probability to my missing the perfect setting on a few props, the above figures for the Mk II Mite imply a peak output of some 0.064 BHP at around 7,000 rpm - exactly the maker's claimed speed for the engine. The manufacturer's suggested airscrew sizes also appear quite appropriate on the basis of the above figures. The engine exhibited no mechanical problems of any kind during the course of this test.
The Mk III Mite shows a clear performance edge at the higher speeds, but it's perfectly reasonable to suppose that this may be at least partially down to inconsistencies in terms of fits and assembly. The overall finding here is that both tested examples of the Mite are perfectly useable engines with a quite reasonable performance by the standards of their day.
The End of the Line
As far as we are presently aware, the previously-mentioned advertisement for the Mk III Mite from the June 1948 issue of "Aeromodeller" represents the engine's swan song in the contemporary modelling media. There may have been later ads, but if so we don't have access to the relevant issues.
It thus appears almost certain that production of the Mite ceased at some point in mid 1948. No doubt, as suggested by the unknown dealer whose letter appeared in the April 1948 advertisement mentioned previously, the rather angular and "home made" appearance of the engine had a lot to do with its evident failure in the marketplace. The seemingly large number of returns of the Mk II (as reflected in that June 1948 advertisement) must surely have played a major role too in terms of the engineís reputation.
However, the disappearance of the engine was probably inevitable anyway in the face of the ever-increasing competition from other manufacturers. ED had of course been there all along with their 2cc models, and as of mid-1948, new competing models were appearing from the likes of Mills (with their significantly updated Mk II version of the 1.3), Frog with their 180 and Aerol with their 2cc Hurricane (shortly to be replaced by the even better Elfin 1.8). In addition, the K Engineering were soon to release their lightweight 1.96 cc Falcon and Kestrel models.
All of these new designs had greatly improved performance levels and were far more aesthetically pleasing in addition. The Mite would have had to be drastically updated and "repackaged" yet again to meet this level of competition, and perhaps the rewards from the venture simply hadn't been sufficient to justify such a step.
However, the cessation of Mite production does not seem to have dissuaded the irrepressible Mr Smith from remaining active in the model trade! In mid 1950, we find an advertisement in "Aeromodeller" that was placed by a company calling itself "The Model Stadium". This company offered a range of modelling goods, including both kits and engines. Interestingly enough, the new company continued the previously-mentioned hire purchase option first offered during the final months of the Milford Mite; in effect, an early example of buying on credit before such buying became the norm. Some degree of continuity in management may be implied here. They were also spending quite freely on the promotion of their business, running an ongoing contest in which the prize each month was a new engine—albeit not a Milford Mite, which was not mentioned at all!
The Model Stadium gave its address as that of the former Milford Gauge Company, and even the telephone number remained unchanged. There can be little doubt that this was the same business carrying on under a different name and expanding into the retail market sector in a far broader sense than before.
It is actually possible that the business had changed hands by this time. Another Model Stadium advertisement from the September 1950 issue of "Aeromodeller" implied that the owner at that time was a certain Mr JC Snell.
The Model Stadium was still in business in 1958, at which time it was still placing "business card" advertisements in Aeromodeller. In October 1952, the company was the featured dealer in Model Aircraft's monthly "Trade Notes" column. The manager at that time was said to be one KS Reid, but the individual who reportedly "attended to modellers' needs" was none other than a certain Mr JR Smith Jnr, assisted by his faithful dog Thunder. There was even a photograph showing the elusive Mr. Smith, unmasked at last!
OK, so what's the answer to the question posed in our heading—was the Milford Mite really England's worst-ever diesel? Depends on your point of view, I suppose. I admit that I'm hard pressed to think of a British production model diesel of the period that could match the Mite for lack of sophistication in production and styling terms. If that's your criterion for the title of "England's worst", then the Mite takes the crown, no question. Even my seemingly better-than-average examples leave a fair bit to be desired in terms of their architecture and ove3rall production quality, plus they're rather heavy for their power output. But then, so is the Mk I Mills!
If your criterion is general "useability", then once again it's hard to think of a less flexible British diesel than either of the first two variants of the Mite with their tiny built-in tanks which severely restricted the available motor run, did not permit the use of a separate fuel tank and thus restricted the engines to free flight applications using upright mounting only. The third variant with its revised tank was considerably more flexible in terms of potential applications, but that was definitely a case of too little, too late.
However, there's no doubt at all that my examples of the Mite are easy-handling and well-fitted engines that run extremely well, seems quite robust and would definitely do a fine job of flying a basic sport free-flight model. Viewed in those terms, the Mite was at least a practical design, if nothing else. It was consistency of execution rather than any specific design flaws that seem to have let it down.
So I have to confess to having slipped into the camp of the heretics on the basis of this evaluation! The Mite is a fascinating testament to the enthusiasm and energy of its makers, who were clearly Motor Boys at heart and are to be commended for at least having a go! Not only that, but they came up with a design that was well outside the box and was capable of delivering a more than acceptable performance by then-current standards. It's too bad that their design capabilities were not matched by consistency in terms of quality.
I'm very happy to be the owner of several examples of their work which prove that they were capable (on a good day, perhaps?) of producing an extremely useable engine. In that sense, the Mite was very far from being "England's worst". The fact that not all examples of the engine seem to have achieved this standard in no way diminishes my affection for the makers' ill-starred product or my admiration for their enthusiasm.
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