sandpiper Posted August 28, 2013 Report Share Posted August 28, 2013 Questions for those of you in countries other than the USA who have in flight adjustable props: 1. What take off and climb RPM do you use? 2. What are typical RPM and manifold pressures used in cruise? Link to comment Share on other sites More sharing options...
C ICEY Posted August 28, 2013 Report Share Posted August 28, 2013 BC Canada here. I am no mechanical expert. I've got a Kaspar hydraulic adjustable on my 2003 CT2k. There are constant speed controllers available for it, but I have become accustomed to the hydraulic, so I'm happy with it.. Just overhauled bearings and pushrods at 1000hrs, it has operated flawlessly. The blades are a bit crazed from years in the sun, but otherwise fine. Take off roll will see the RPM climb quickly to 5800 if the pitch isn't coarsened (two notches before rotation) and it is easily possible to overspeed if not careful. \\\I simply choose the rpm you want for the throttle setting. My climbout is variable, commonly 5550-5600 for less than a minute, before I settle into a 5400-5500 climb. Depending on hill in front of me. WOT at about 6000' is about 5350 with full coarse and an honest cruise of 120, I can choose to go at 5500 all the time, but tend to throttle back half, and run the RPM at 5300-5400, cruising at about 110-115. lifetime fuel consumption is about 17.5litres per hour. I also fly at times throttled right back at 4250 and all places in between. Adjustable is essential IMO when flying in our terrain. When I first got the aircraft there was 300hrs on leaded fuel in it and a packed out gearbox that rattled at 46-4700rpm. A repack and unleaded has kept it smooth running though all rpm since. I don't have manifold pressure gauges. maybe someone can tell me about what happen to the manifold pressure as RPM is maintained and throttle reduced.... Link to comment Share on other sites More sharing options...
josjonkers Posted August 28, 2013 Report Share Posted August 28, 2013 I have the same set up as Mike and my full throttle fine pitch rpm is 5400 and I start coarsening it up shortly after rotation . Climb out at 5200 and I either coarsen it up further depending on climb out speed or easy back on the power. Rest of the flight is around 5000 to 5200 rpm that I control by mainly Variable pitch augmented by slight differences in power setting. Link to comment Share on other sites More sharing options...
sandpiper Posted August 28, 2013 Author Report Share Posted August 28, 2013 If you are cruising at 5200, what is a typical manifold pressure? Link to comment Share on other sites More sharing options...
Jim Meade Posted August 28, 2013 Report Share Posted August 28, 2013 You guys have controllable props as opposed to constant speed props, right? You set blade angle with a knob or lever? These are Rotax 912s? Normally aspirated, no mixture control? If you adjust your blade angle so that you turn 5800 rpm with brakes locked or immediately on the take-off roll, you'll overspeed slightly as the airplane gathers speed and the prop unloads a little. As speed is increased due to flap retraction and lowering the nose on climb out the prop will unload a little more so another blade angle adjustment may be indicated. Same on a high speed descent. Anytime pitch is adjusted there is a likelihood that the prop will load or unload and the angle may need to be adjusted to stay at the desired rpm. When you ask about MP in response to throttle with constant rpm, I assume you are adjusting the blade angle to hold your specified or desired rpm? In other words, after your prop angle adjustment? Link to comment Share on other sites More sharing options...
Brucegoose Posted August 28, 2013 Report Share Posted August 28, 2013 Climb out at 5500rpm and MAP at 24. At after t/o checks 1000ft I reduce to 5000rpm and maintain 83 kts climb rate, (airfield alt, 3800ft,) Cruise at 5000rpm 110kts ave. MAP at 22,5 Would only use 5800rpm for very short field take off's. Using a Flybox constant speed controler with a Neuform prop. Kind Regards to all on the forum. Bruce Link to comment Share on other sites More sharing options...
Ian Posted August 28, 2013 Report Share Posted August 28, 2013 T/O climb out @ around 5600 rpm, reducing once airborne with positive rate of climb by pulling 1 or 2 "notches2 back. Cruise is typically about 4700 rpm giving around 110knots and using about 17 to 18 litres/hour. I use that as the guide rather than manifold pressure because a) it is a Neuform VP prop rather than constant speed - and I find the MP display on the Dynon jumps around too much to be useful (in fact I've turned the display of MP off!) Link to comment Share on other sites More sharing options...
Roger Lee Posted August 28, 2013 Report Share Posted August 28, 2013 Ian, You can fix the MAP fluctuations. Up at the carb cross over tube where the map hose slides on, just insert a Bing carb idle jet in the end of the hose and it will make it as steady as a rock. This is an acceptable way to dampen the MAP pressure. Mine is steady as a rock. Link to comment Share on other sites More sharing options...
Ian Posted August 28, 2013 Report Share Posted August 28, 2013 Ian, You can fix the MAP fluctuations. Up at the carb cross over tube where the map hose slides on, just insert a Bing carb idle jet in the end of the hose and it will make it as steady as a rock. This is an acceptable way to dampen the MAP pressure. Mine is steady as a rock. Aha!! Perhaps I'll try that - Thanks Roger Link to comment Share on other sites More sharing options...
C ICEY Posted August 28, 2013 Report Share Posted August 28, 2013 Jim. 912 S, and yes it is an inflight adjustable Kaspar prop. I find that I adjust it often depending on the flight configuration. Mine is hydraulically adjusted, but IZZY has an electronic true constant speed controller. Heinz might be able to answer some questions on that one. I had the opportunity to put one in as well, but am so comfortable with the hydraulic that I opted to leave it in as is. I flew a 2011 CTLS with a constant speed, and it appeared to be a very nice installation and functioned as advertised. Nothing special enough about the LS to make me want to replace my CT2k, though. Link to comment Share on other sites More sharing options...
josjonkers Posted August 28, 2013 Report Share Posted August 28, 2013 If you are cruising at 5200, what is a typical manifold pressure? Don't have manifold pressure instrument. Link to comment Share on other sites More sharing options...
sandpiper Posted August 28, 2013 Author Report Share Posted August 28, 2013 Thanks guys. You answered my questions. Also, one of the guys here in the airpark found some Rotax power information/recommendations that showed, for example, 75% power as being 5000 RPM with 26" MP. Link to comment Share on other sites More sharing options...
Jim Meade Posted August 29, 2013 Report Share Posted August 29, 2013 Here is an SI somewhat on this topic. Haven't had time to study it. http://www.flyrotax.com/portaldata/5/dokus/d04645.pdf Link to comment Share on other sites More sharing options...
C-IZZI Posted September 22, 2013 Report Share Posted September 22, 2013 My 2006 CTSW has a Kaspar 3 blade propeller and is equipped with a constant speed governor (electrical). Takeoff rpm is set at 5700rpm wot. climb at 5500 rpm wot, cruise a 5200RPM, normally 22" manifold to wot depending on cruise altitude. True cruise speed 125+ depending on altitude, usually above 10k feet. I carry oxygen. (Mountain High) It is very rare to get more than 22" mp above 7-8000 feet which is where we operate mostly. The setup as it is works very well and has been flawless. My home base is in the Canadian Rocky mountains. Link to comment Share on other sites More sharing options...
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