You mentioned that you don't have a speed break or flaps. What is your landing distance on concrete and grass?
Joe On Nov 30, 2014 3:27 PM, "colin hales via KRnet" <krnet at list.krnet.org> wrote: > > Hi all, > A couple of things. First, I'm too busy, articles, video editing, things > are getting neglected, like my parents and friends. Lots to do before I > return to America in January. My own fault so I try not to complain. > I read a lot of the comments on Krnet. > There seem to be a few repeating issues that I thought would reply to. > Engine reliability. > Non of them are. I wouldn't expect any light aircraft engine to do more > than 500 hours without a good look over. I looked at one of my exhaust > valves while repairing a leaking exhaust gasket. It looked rough, hardend > plating corroded and cracked at base at 300 hours. I replace my exhaust > valves each 300 hours now. If you don't, they will brake, or stick or both. > Temps are vital, it took a long time to make sure my engine doesn't even > get hot. > Its not really the engine or designers fault. Its operating conditions, > operators and maintenance. I've read many of the reports of the jabiru > engine failures and sort of knew why most of them had happened. > Lets get real. The Jabiru engine has had next to know research or > development. During the early days, the owners were doing it. I learnt > quickly about 5 vital things to look after my Jabiru, by seeing what > happened to the operating parameters, temps pressures when various > operating conditions were applied. None of them have ever been added to any > news letter or information advice from the manufacturer and I've given up > telling people now. No one listens.I even was asked to write an article for > our society about Jabiru engines. I entitled it, "Jabiru engines and what > they won't tell you about them!" Highlighting about 10 issues, 5 I though > vital for safe operation of the Jabiru engine. They never published it,said > it was too inflammatory and open to the layers... > I know people will now say that they have had thousands of trouble free > use from their engines, well all I can say to that is that , you are either > a diligent operator and maintainer, or you have been lucky. > The Rotax engine had a lot more development thrown at it, and you have to > pay for that in the cost of the thing. Get what you pay for... The Jabiru > engine is expensive as well, that's because you are paying for a decent > power to weight ratio. That's all. > Its no good really. Its still too delicate. I use it though, but monitor > it and all four egt and cht parameters rigorously and check heads and > tappet clearances for signs of change or deformation regularly. Seems to > keep going. But I don't like it. I would love to buy one and not have to > think it was ever going to quit for 2,000 hours as they say, but its a > joke... Not funny when they do break and seemingly they do. Anyway... > Next, speed brakes. A KR needs to be light and none complicated if it is > going to perform well. 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. So don't worry about how many holes to put > in your speed brake, save yourself a lot of time and weight and > complication and use the prop as a brake instead. This only works if you > have a starter motor, I've accidentally let it stop once or twice out on > the taxi way. But its safer too. No panic trying to find mag switches or > trying to turn mags switch keys, if a dog runs out, as has happened to me. > Just pull the throttle, which your hand is on anyway and it stops. > More ways to skin a cat, which is a funny saying we have here. I'm not > telling anyone anything or want any reply or discussion with this message. > I'm just saying what I do and saying that if you haven't tried it, give it > a go. If it works for you too, brill, if not well, I reckon holes add to > drag. About 20 two inch holes should do. > Keep an eye on those engines, if you have a worry, you are probably right > and you should take a look, it never hurts. > Best regards, > Colin Hales. > _______________________________________________ > 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 >
