I would suggest that the best indicators for evaluating your (GA) fixed props performance, at a given pitch setting, are: Indicated air speed for a given RPM at the indicated (or calculated) fuel flo
First let me apologize to the group for trying to dig so deep into this subject. I am by no means an expert but I have been around a bit. However, my goal is to learn and as an Engineer I do tend to
Fwiw, my mono classic with the short but wide warpdrive has the same expected issue: If set to keep it above 5300 static and in the climb (to reduce gearbox/spline abuse), then my cruise is also slow
Thanks PeteZ and I think we are starting to get a great conversation going. First: I don't think you should fixate on the static RPM number, it's meaningless as long as the TO performance is acceptab
Wow that is low. Our local authorized Rotax service guy would shake his head, and show me the chewed customer splined shafts he has on his shelf. Petez as long as the TO performance is acceptable and
Forget to ask: 80? or high compression 100hp? (Might be less of an issue on the 80) as long as the TO performance is acceptable and you are not overloading the engine during climb. See the blurb I ad
Word of caution; Its my opinion that airframe/propeller manufacturers want to optimise sales (particularly in the highly competitive sport aircraft market). They will happily compromise engine servil
Guys, The main problem with playing with pitch on the propeller is one never wants to overload or lug the engine on takeoff. See Rotax SL 912-16R1 which states to set WOT for takeoff no lower than 52
Hi Chris, The SL that I referred Griffo to back in your other post states the you should have 5200 rpm min at take off WOT. It doesn't say what part of TO. It also doesn't mention any thing about sta
Hi Peter, If you have 5200 rpm STATIC, you will get that as soon as you open your throttle, to start the TO run. The rpm will climb as you accelerate, moving up into the 5 min max operating range. If
I did continue my research (learning was after all the intent of this posting) and found a Rotax SL-912-016 which does state that WOT operation during takeoff should not result in an RPM lower than 5
If you want to find out just how far you can go with an unmodified Rotax 912 ULS - Google, Robin Austin and the story of his record breaking Sonerai VH-SGS http://www.worldrecordplane.com/ (Note: the
For what its worth; me things the CTLS & Sport cruiser are worthy aircraft that are more hype than performance. Yet to hear of one actually achieving the performance claims, in real world operations.
The SL (SL-912-016R1) doesn't say what is being reported in this thread. It says: "Continuous use of engine speed below 5200 rpm must follow manifold pressure graph...." So a takeoff and climb to 500
And it's all at <3500'. Above which, there are 'no rules'. DMcF. graph...." operation at >5500rpm. Cruising at 4000rpm is permitted at <27" MP, for example, and the SL merely says operation outside o
To respond to your original question, attached is some recent speed data. It's a bit 'all over the place' if plotted. Duncan McF and found a Rotax SL-912-016 which does state that WOT operation durin
As always Bud, an excellent post. Thanks for taking the time. Cheers! PeteZ to overload or lug the engine on takeoff. on the 912 and 912S/914 with specified fuel octanes. assures you that detonation
I join PeterZ in thanking Bud for the post as well as those who replied in this post. I read the SL and I agree Bud that Rotax concern revolves around the issue of detonation. Valid and much more ser
Chris, 3 points: Detonation will reduce the service life of your engine ie longevity. The description of fuel for your country/location may not be easily interpreted in another; In Australia we have