DH Cirrus Mk I
No. 22 in a series compiled by David R. Janson,
SAM #273, AMA #78416 and MECA #210-04.


The first I had seen of this magnificient inline four-cylinder, four-strokecycle model engine, was the picture and description on the last page of MECA BULLETIN #62, Jan-Mar, 1977. Known then as the D&B engine it had been a hot item at the April 1976 Toledo bash... 1.5 cid, 20 oz. wt, spark ignition marvel, selling for $1,200 with production forcast in Nov. 1977! Contact D&B Model Aircraft, 6823D Colonial Dr., Mentor, Ohio 44060.

The engine's designer was master machinist Merritt A. Zimmerman of Cleveland, Ohio who was pictured with it in the nose of a WWI fighter plane in a couple of national hobby mags at that time. He had teamed up with one Chester DuBiel of 7010 Arcadia Dr., Parma, Ohio, designating Brown Hobby of NYCity to advertise the engine resulting in Brown's ad, MAN Sept 1977 and Feb. 1978 for $960! Then MECA Swap Sheet 1180. Sept, 1979, p.9, under member Chester F. DuBiel, noted:

"FOR SALE: I have a limited number of Z&H Cirrus, four cylinder, four-cycle, inline glow engines for sale. All engines are hand crafted and are run at the factory prior to shipment. This is the first production run on these engines and have low serial numbers. Trade in your ignition engines or race cars on one of these engines."

In the March 1980 RCM, that old columnist Claude McCullough, waxed eloquently about the engine. And from time to time the magazines ooohhed and aahhed about it. In the fall of 1980 Wally Warner of Technopower 11 radial fame was selling his fine group of multicylinder engines; he listed the prototype Zimmerman Cirrus at $2,500, and production Cirrus #5 at $2,000! Now, interestingly enough, MECA BULLETIN #72 combined with Swap Sheet #90, May 1981, brought out another ad from BuBiel of Parma, Ohio noting:

"I will be taking orders for the Z/H Cirrus engine. Delivery about Jan. 1982. Price $1,350.00 plus postage (Jeez!) Those who placed orders for these engine in the past, should be getting them sometime this year. Please contact me if you still want the engine."

This, of course, was a full five years later after the initial Sept. 1977 announcement of the engine! While total production numbers of the Z&H Cirrus are unknown, I do know in answer to my inquiry for pictures (those left side) to MECA member Dwight Hartman, Argenta, Illinois, one of the very early members and an avid collector, he bought his #38 at the Villa Park trade show in Ohio, October 1984. And the engine faded from sight!

Let's take a break from chasing the name, production and sales history of the Z&H Cirrus Four, and look at it in detail. Designer Zimmerman had spent years on the prototype. The incredible sand casting of an upper and lower case which had eight pushrod seats on the left side which also had the bypass, a smaller and complete two piece sand cast rear case cover which had the intake to which the OS automix carburetor was attached, were difficult enough to set up. The four machined aluminum heads, all part of a single machined aluminum bar stock capped the four individually machined steel upper finned cases and were held to the lower case by ten long steel bolts. Four individual bronze exhaust ports were angled up to a single horizontal outlet with rear open end. Four vertically mounted glow plugs screw into the side of each cylinder head. The keyed prop drive washer, the aluminum prop washer, small "nubs" on front" and the steel nut completed the look. It is impossible to describe the inner workings of course. On the right side is the large circle with "ZH CIRRUS" molded on. All pushrods and seats are open. Polished aluminum, polished brass, black anodized steel all give a most attractive finish to this "square" appearing engine. The small side mounts with bolt are different. Collectors wish they weren't so expensive and more were available... an incredible engine.


Footnote (Ed)

The sadly poor quality scans on this page show a "genuine" Z&H Cirrus which differs significantly from the engine pictured in the Brown Hobby advertisement. Apart from the visible differences, the text states that the latter had a wet sump. I don't believe any engines like this were delivered as the "production" engine is essentially identical to my own engine (pictured) which was built from castings. These appear to be the same as those used for the Z&H engine except for the removal of the name cast onto the upper crankcase section. The publication date of Dave Jansen's review is not known, but with the passing of time, we can add some more facets to the story.

In 1988 when Robert Washburn announced he was launching a magazine dedicated to model IC engine construction, Merrit Zimmerman mailed him several sets of plans with a note saying with these what you will... One of these was the 1/6th scale Cirrus Mk1 described above. Redrawn CAD plans were serialized with a construction feature written by the now well known English designer/builder, PEL (Eric) Whittle. This four issue series commenced with issue 49, Volume 9, of Feb/March 1996. The inside rear cover page "Subscriber's Advertising Section" of that issue contained the following:

1/6th-SCALE CIRRUS Mk1 CASTING SET - includes ten (10) aluminium castings: upper crankcase, splash pan, front cover, rear housing, housing cover, four pistons, carburetor, and a set of drawings. Cost is US$125.00 in USA (foreign, add US$10.00 postage). Send to: Chester DuBiel, 7010 Arcadia Drive, Parma, OH 44129.

This is the same Chester DuBiel mentioned in the story above, showing that you can't keep a good design down. In fact, following his construction article for SIC, Eric Whittle reduced the Cirrus to 1/9th scale and built one from bar-stock. This was serialized in the English magazine, Engineering in Miniature. This 1/9th scale Cirrus then formed the basis for his Aero V-8 that was serialized in the Model Engineer, thus reversing the full-size process where a WW I Renault aero V-8 was cut in half to produce the Cirrus Mk 1!

Eric made the construction look so easy, I said to myself, hey! Even I could do that! A set of castings were ordered from Chester DuBiel sometime in 1997 and the results can be seen ten years later in the Cirrus Construction Log.


This page reprinted from "Model Engine Designer and Manufacturing Profiles" by permission of the author, Mr David R. Janson.



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