Engine, Propeller, Engine Mount and what not for my IBIS RJ.03
An IBIS is a relatively clean ship and a rather light one at that. At appr. 100 kts (economy cruise) we only need some 28-30HP to stay aloft at maximum takeoff weight.
and climb-out performance on a hot day at all up weight. 'Volucelle', the IBIS predecessor, was tested with VW-derived aero engines as small as 55HP but generally, 65HP and above is recommended. Anything over 80HP will push the plane over its 140 kts Vne rather easily (especially when the propeller is geared towards the upper speed range), so it wouldn't make any sense to install such a large engine.
As the Formula-V scene has shown (Sonerai, V-Witt, Cassutt and other VW-powered racing aircraft) it is possible to get a bit over 100HP out of a smallish (1600cc within Formula-V rules) VW at an RPM of a bit over 4000. However, forcing that poor thing to digest that much power and shed off that much heat wreaks havoc with its TBO (whatever significance that has in the context of homebuilt aircraft, as we're operating 'on condition'). From some web reports one could get the impression that Formula-V jockeys spend as many hours maintaining and modding their powerplant as they do flying their ship.
For my IBIS I'm going to assemble a VW-based aircraft engine that is configured for durability, rather than all out power. The next couple of links lead to pages where I document my current thinking:
©2004-2012 IBIS RJ.03 "The French Canard" homebuilt aircraft project
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