Colin, What type of wheel breaks do you have?
Joe Nunley On Nov 30, 2014 8:35 PM, "Mark Langford via KRnet" <krnet at list.krnet.org> wrote: > Colin Hales wrote: > > I haven't got flaps or a speed brake. You don't need >> them. People keep saying that "They float!" How? Its got tiny wings! >> The problem mostly seems to be that people need a high throttle >> position to keep their poorly idling engines going on the ground at >> say, 700 rpm. This unfortunately turns into about 1,400 rpm in the >> air. No wonder it floats, thats still about 1/4 throttle. If you >> remove the idle stop for your engine all together, if you close the >> throttle completely, it now acts like a exhaust brake. The engine >> will never stop in the air, it just windmills at 500 rpm causing >> massive drag and the aircraft stops and falls out the sky. When you >> land and the idle gets lower as they airspeed decreases, just crack a >> little throttle back on. >> > > I have several problems with the above paragraph. One is that even if > your engine is switched off and the prop stopped (I've never seen mine > windmill, either the Corvair or the VW), a drag brake is useful. If > nothing else, the brake acts as another control system to provide more > flexibility in landing, whether "deadstick" or normal. It's another tool > in the box, just like slipping. Another benefit is added drag behind the > CG, which helps to stabilize the airplane while landing. Nothing like a > drag chute, but a small step in the right direction. > > As for "poor idling at 700 rpm", most aircraft makers, and indeed auto > makers, probably wish they could make their engines idle reliably and > smoothly at 700 rpm under all temperature conditions. Most everything I've > driven is stabilized from the factory at something like 950 rpm. The best I > can do with N891JF's engine is idling at about 800 RPM, and the Corvair is > similar. This puts me at about 1050 to 1100 RPM on short final. > > I've never seen a carburetor that would run 700 rpm while open at 25% > throttle. Most carburetors (or what passes for a carburetor in the case of > the POSA) either have a dedicated idle circuit and require no throttle > opening at all, or have a slight opening that might be 5%, rather than 25% > open, when running at idle. 25% throttle might be 1800 rpm, but not 700 > rpm, at least not on a "normal" engine. > > You have far bigger gonads than I do if you fly with no throttle stop and > routinely let the engine almost die on every landing. Fiddling with the > throttle to keep it running on rollout seems another distraction that I > don't need. I pull the throttle back to idle when I'm abeam the numbers > and leave it there unless I need power to make the runway (which is > rare...although I may slip it to kill extra altitude). I guess I can't > argue with your success, but it's contrary to everything I know about how > to drive cars or fly airplanes. It's one less thing to fool around with > while landing. That cure seems worse than the disease. > > I guess I can't say I've tried it, but I have tried belly boards (both > before and after), and I do highly recommend them... > > -- > Mark Langford > ML at N56ML.com > http://www.n56ml.com > > > _______________________________________________ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
