Zenith Zenair CH601 HDS – homebuilt with an impeccable pedigree
Tags: 'bare' set of plans, 'Biggles' books, 'conventional' wing, 'Gimlet', 'wash-out', 100 hp, 140 mph, 4 gallons/hour, 80% power, aeronautical background, Aerospatiale, aircraft, airfield, available working area, avgas, Aviation, Avions Robin, awards and honours, boys, Canada, Canadian-based company, Captain Lorrington King D.S.O., CH601 HDS, Chief Engineer, Chris Heintz, Commando, Commando officer, composite materials, Concorde, Cotswold Airport, cruising speed, D.S.O., damage to certain components, DCH-7, De Havilland, De Havilland Canada, DHC-7, E.T.H. Institute, EAA, engine, engine cowling, England, Europe, excellent performance on modest power, exclusive licence, fibreglass, fibreglass skinning, finished components, formation of wingtip vortices, founded in 1973, four-cylinder engine, France, full-span ailerons, fuselage, fuselage framework, fuselage sections, G-CEAT, Gloucestershire, grass, Great Britain, Hoerner wing tips, home base, homebuilder, increased wear, instruments, Kemble, kit of parts, LAMA, lead, Light Aircraft Association, local branches, maximum 'lift area', metal monoplane, metals, Mexico, minimise induced drag, Missouri, mogas, no flaps, oil tank, PFA, Piper, Piper Cherokee, polyurethane foam, polyurethane foam fuselage sections, Popular Flying Association, Rotax 912 ULS, Rotax service instruction SI 912-016, series of adventure books, Somerset, struts, Swiss engineer, Switzerland, tapered 'speed wing', technical support, Terrance Smith, type of aircraft, U.K., USA, W.A.R. Replica kits, W.E. Johns, wing, wing tips, wingspan, wingtip vortices, wood, wooden main spar, WW2, Yeovil, Zenair Ltd., Zenair Zodiac CH601 HDS, Zenith Aircraft Co.
If you wish to build your own aircraft in the U.K., you would be well advised to read widely, talk with other builders, and then join the Light Aircraft Association! Formerly known as the Popular Flying Association (PFA), the LAA provides technical support for the homebuilder; their local branches (known as ‘Struts’) are scattered around the country.
Basically, there are three choices facing someone wishing to build a light aircraft – wood, metal or composite materials. Most aircraft designs will require the ability to work in all three classes of materials, (the W.A.R. Replica kits have a wooden main spar and fuselage framework, but polyurethane foam fuselage sections and fibreglass skinning), but it is wise to match your skills and available working area to the type of aircraft, whether you intend to buy just a ‘bare’ set of plans, some finished components, or a whole kit of parts (minus engine and instruments).
The aircraft shown is a Zenair Zodiac CH601 HDS, built by Terrance Smith of Yeovil, Somerset. This metal monoplane is produced as a set of parts by the Zenith Aircraft Co. of Mexico, Missouri (yes, the town is called Mexico!), who have the exclusive licence to sell the designs of Zenair Ltd., a Canadian-based company, founded in 1973 by the Swiss engineer, Chris Heintz (Zenith is an anagram of Heintz). Chris Heintz has an impeccable aeronautical background – a graduate of the E.T.H. Institute in Switzerland – having worked for Aérospatiale on the design of Concorde, and for De Havilland Canada on the DHC-7, as well as being the former Chief Engineer of Avions Robin in France.
G-CEAT is parked on the grass at Cotswold Airport, Kemble, Gloucestershire; it is powered by a Rotax 912 ULS, a four-cylinder engine putting out 100 hp (maximum) and running on MOGAS. This is capable of giving a cruising speed of 140 mph (at 80% power), whilst consuming only 4 gallons/hr. There is a small problem, in that if you are ‘touring’ away from your home base, you may not, necessarily, find it easy to procure MOGAS on any airfield or strip you use; if AVGAS is used in the Rotax engine either increased wear or damage to certain components may ensue. In any case, when using AVGAS, the oil will need to be changed every 50 hours, and (possibly) the oil tank removed periodocally to remove any lead which has accumulated on the bottom; Rotax service instruction SI 912-016 gives all the necessary data.
The performance of the CH601 HDS has been increased from the previous model by the use of a tapered ‘speed wing’ with near full-span ailerons (there are no flaps, rather like another aircraft Chris Heintz worked on). I am told that it flies ‘something like a Piper Cherokee’; high praise, indeed.
You might have noticed the distinctive Hoerner wing tips, with their characteristic ‘wash-out’. These give the maximum ‘lift area’ for a given wingspan, as they minimise induced drag caused by the formation of wingtip vortices in a ‘conventional’ wing. All things considered, the Zenair Zodiac CH601 HDS is a ‘nifty’ machine, giving excellent performance on modest power. Chris Heintz well deserves the many awards and honours that have been heaped on him by the EAA, LAMA and other organizations.
You may notice that the aircraft bears a name on the starboard side of the engine cowling – ‘Gimlet’. I can only surmise that it is meant to refer to the nickname of a certain fictional Commando officer, Captain Lorrington King, D.S.O., a.k.a. ‘Gimlet’, who appeared in a series of adventure books for boys written by W.E. Johns (much better known for his ‘Biggles’ books) during, and immediately after, WW2. Oh yes, and the other flapless design Chris Heintz worked on? Concorde, of course!
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