Thread: Engine rpm

Hi Ed,

It still might be pilot skill, but know one will ever know, but you and me.

Thanks for the info Roger i will give it a try and let you know the result i am away for a couple of weeks tomorrow so will do it when i get back ..I have always felt it was struggling a bit on take off at max weight so will be interesting to see difference

Cheers Mike

The most common and persuasive reason given for operating at lower rpm is the complaint that at 5,500 rpm the noise level is too high.

Question is, is the noise level at 5,500 dependant on pitch? in other words if you were pitched to achieve 5,800 would 5,500 cruise be as noisy as 5,500 cruise if you were pitched to achieve only 5,500?

Hi Mike,

Having your plane propped to get 5500-5600 rpm at WOT has two good benefits.
1. To my understanding many CT'ers in the UK fly out of 300m grassy airstrips. This rpm setting will get you off the ground sooner on short runways with grass.
2. In case you bounce or flare it to hard getting you back into the air and then have the need to save your butt the flatter pitch prop will spin up to speed quicker and have a better climb or altitude sustaining capability over one that is only set to 5200 WOT. If you level the nose quickly and go full throttle you would be less likely than those who have it set at 5200 to dump the nose into the ground.

So we try to balance all these. I will tell you from years of experience with the 912 that going from 5500 to 5200 WOT with the 912 will cost you on many fronts not to mention lugging your engine over its lifetime. This and a few other reasons is why FD got away from 5200 and went to 5500 rpm WOT eventually.

For me and I think for a large part of the 912 community 5500 WOT is a good setting for balance unless you need a little more flight characteristic one way or the other. The guys with the in flight adjustable constant speed props have the best of both worlds on settings if they use it wisely.[/QUOTE]

Roger,
I have my annual this month and currently get about 5150 on takeoff at 600' MSL. What should I ask my mechanic to do in order to get the most out of my Rotax? I have a CTLS with 100 hrs. I fly out of airports at 600' MSL and 3250' MSL.

Doug

If you need to get hold of Roger you'll have to get him @ "*******.com" he is no longer on this forum

Originally Posted by Arnold Bronson

If you need to get hold of Roger you'll have to get him @ "*******.com" he is no longer on this forum

That's absolutely ridiculous

Doug,

Try flattening out your pitch by one degree then fly it. You may have to fine tune it from there. Make sure your mechanic knows what he is doing and gets all blades the same. On your first flight pay close attention to RPM. I only do a couple of these a year since I am not in business. Others out there who do these on a regular basis could probably tell you exact degrees.

Send me a PM with ypor phone number if you want to talk.

Doug,

My PM function is not working. Call at 503-508-8877.

Doug,
RLee email is roger@lsamechanic.com
Tim