Performance Figures for the RV-12

NinerBikes · #1 09-22-2019, 10:34 AM

In looking at the performance figures, a distance range is listed for the RV-12 running 5000 Rpm, and also at 5500 rpms.

https://www.vansaircraft.com/rv-12is...raft-details-2

Is it possible or advisable to run the Rotax engine at 5500 rpm on a whole tank of fuel?

I was under the impression that the engine should not be run at full throttle for more than 5 minutes.

Depending on how you pitch your prop, for climb or cruise, is running the motor at 5500 rpms for more than 5 minutes advisable? Or is it pretty close to the "edge". What kind of manifold pressure should be expected, at 7500 ft under normal ATM conditions?

Azjulian · #2 09-22-2019, 10:40 AM

5500rpm is the max continuous rpm of the engine
5800rpm is the rpm they call ?take off rpm? and they indicate a limitation of 5 mins at that

Dave12 · #3 09-22-2019, 10:45 AM

The 912 can be run all day at 5500. Both of the ones I had seemed to enjoy it.

NinerBikes · #4 09-22-2019, 10:54 AM

Thank you. The friend I fly with, usually runs between 5100 and maybe 5300 rpm.... we usually see about 102 to 107 kt IAS and 115 kt TAS, both coming and going, average, if close to 20 to 25C OAT. Plane is at 175 hrs, motor broken in, and with wheel pants and nose gear fairing.

Mods, can we close this thread?

Piper J3 · #5 09-22-2019, 11:08 AM

I run 5500 all the time. You can run above 5500 into the yellow for 5 minutes.

NinerBikes · #6 09-22-2019, 11:24 AM

Quote:

Originally Posted by Piper J3

I run 5500 all the time. You can run above 5500 into the yellow for 5 minutes.

What's indicated fuel burn gals/hr on your Skyview 1000, vs actual fuel burn, at that pace?

Piper J3 · #7 09-22-2019, 12:41 PM

My D-180 shows about 5 to 5.2 at 5500 depending on how it settles out on any given day. Doesn't rally matter. I'm not going to quibble about fractions of a gal.

rvbuilder2002 · #8 09-22-2019, 01:55 PM

An RV-12 with the prop pitch set to provide the best overall performance will not be at full throttle in cruise flight until flown in the low to mid teens.

An RV-12 that requires full throttle to attain 5500 RPM (max. continuous rated rpm) at lower altitudes in cruise has the pitch setting of the prop set to course.

NORM T · #9 09-22-2019, 02:34 PM

My one time test experience is quite similar to others with wheel fairings, approx: 5000 RPM/112 kts/4 gph; 5200 RPM/122 kts/4.3 gph (best economy); 5500 RPM/127 kts/5 gph; 5800 RPM ran a little too close to Vne for me, more than 130 kts,(didn't note fuel burn rate!) but liked results.
Norm

scottmillhouse · #10 09-22-2019, 03:13 PM

Everyone seems to settle with something a little different to match their flying style and the plane. I settled at about 5350-5380 cruise at Vans 71.4 pitch giving about 116 knots with about 5.0-5.5 gph. In the Southeast we have a lot of updrafts and downdrafts over varying terrain and I found if I went higher I would frequently exceed 5500 in updrafts. 5380 gave a comfortable margin both ways to not have to play with the throttle. Also I keep the speed up in climb out not to go lower than 5200 under full throttle to avoid possible detonation.

I wasted a lot of time playing with prop pitch but surprise/surprise found Vans 71.4 best over all compromise for speed and climb. Yes you can pitch for 128+ knots and have Dynon Betty yelling at you but maintaining climb over 5200 gives a very low climb rate especially at full gross and at high summer temperatures.