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RV10 Real World Performance at Various Altitudes

rvanstory

Well Known Member
Finally got an oxygen bottle for higher levels. So, took the 10 up today to see how it performed at various higher altitudes. I have a standard compression IO-540 and 2-blade Hartzell prop. Tested at 8,500 / 10,500 / 12,500 / 14,500 / 16,500 and 17,500 all running lean of peak @ 2,400 rpm and WOT. I was surprised how little KTAS degraded at the higher altitudes (from 169KTAS to 162 KTAS) and it performed equally well from 8,500 to 12,500 ft. It seemed to be happiest at 12,500 with lower GPH fuel burn and 168 KTAS.

Also surprised how efficient it got at higher altitudes. At 17,500 Garmin showed 19.5 statute miles per gallon! Here's pics of the performance at 2,000 increments....
 

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Try 2500 RPM, WOT. Fuel burn is about the same but I got another knot or two out of the plane at the higher RPM.

This is prop dependent - on my RV-8 I found 2500 RPM to be a happier place on the engine when high. Opposite of expected results. This is with the 74” Hartzell BA prop. Your prop/airframe combo may be different.

Carl
 
Thank you for sharing this Randy. I've been meaning to do this myself to chart it all out. Interesting that at 12.5k and 14.5k the same GPH, same with 16.5k and 17.5k.
 
RV-12, 15,000' held 500 fpm all the way above 10k. About 4gph and 110kts TAS.

Not bad for a snowmobile motor ;-)


Ohhhhh - sorry

Thread drift :p
 
I don’t found the same thing with my -4.. I like to go to 12500, but have gone to 17500 if I need the range. What haven’t you used the lean assist function? I would think that’s an easy way to get repeatable results very quickly.
 
Using SureFly EI on left side and standard Slick mag on right.

Don't know much about surefly, but you may want to play with advance a bit at higher altitudes. My advance is adjustable on the fly and I get a bit less than 9.5 GPH/165KTAS at 14 or 15K. I tend to be closer to peak than at lower altitudes to maintain the 165 and therefore use less advance. The very low MAP seen at the higher altitudes tends to push the advance way out there on many tables, but if you are not also really lean, it is detrimental.

Larry
 
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Reflex at all altitudes?

Yes. Reflex at all altitudes.

Regarding EI advance, not adjustable with SureFly. Advance is either on (at their curve) or off with fixed timing. I was flying right at peak at higher altitudes. CHT’s ran cool enough, even at peak. SureFly is simple, but not adjustable.
 
FL 250
IO-540, 2 Slick mags, 75* ROP for max power.

Flew this profile to test the RV-10 service ceiling. Conditions were optimum. Wouldn't necessarily be able to get this high with sub-optimum conditions.Not much additional benifit flying above 20,000.

Refer to picture for conditions.
 

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MMMV

My 10 will get about 1 gph less than the OP example running ~30 deg LOP, 2360, WOT - throughout those altitudes. Not sure why unless you're not running as far lean as I usually do. Not much difference in TAS for me.
 
FL 250
IO-540, 2 Slick mags, 75* ROP for max power.

Flew this profile to test the RV-10 service ceiling. Conditions were optimum. Wouldn't necessarily be able to get this high with sub-optimum conditions.Not much additional benifit flying above 20,000.

Refer to picture for conditions.

How’d you program those tick marks on your trim and flap settings? Is that doable in G3X serup? Or do you have VPX or some other device that makes that possible?
 
How’d you program those tick marks on your trim and flap settings? Is that doable in G3X serup? Or do you have VPX or some other device that makes that possible?

Adjustable in the G3X menu..

Randy, what is your Surefly setting? FIX or VARIABLE?
 
Thank you, to the posters. I always thought that some day I’d file ifr, swap in a mask (instead of nasal cannula) onto my O2 tank, and see how high I could get my 10 to go. But last year I went with Basic Med and let my second class medical lapse. So now I’ll have to live vicariously, thru you guys!
 
I generally run my RV10 at 21” and 2300 rpm LOP. I reliably get 170-175 TAS (depending on weight) at 10.5 gal/hr at 10,000 ft. TAS starts to decline slightly at around 15,000 ft. I have a Barrett 540-X 290 hp with a Showplanes cowl. Don Rivera helped me balance the fuel injectors to make all cylinders peak within .2 gal. That was very worthwhile and not that expensive.
 
Don’t forget to try flaps zero above the mid teens, mine is faster than reflex when higher.
 
I generally run my RV10 at 21” and 2300 rpm LOP. I reliably get 170-175 TAS (depending on weight) at 10.5 gal/hr at 10,000 ft. TAS starts to decline slightly at around 15,000 ft. I have a Barrett 540-X 290 hp with a Showplanes cowl. Don Rivera helped me balance the fuel injectors to make all cylinders peak within .2 gal. That was very worthwhile and not that expensive.

What prop are you running Robert?

I have the same engine and cowl setup as you but have the 3 bladed Hartzell.
I see very similar numbers to you (maybe a kt or two quicker) but I am only just LOP at about 12gph as I’m waiting on one restrictor from AFP still to finish my balancing. I have one slightly lean cyl which peaks 0.5 gph before the rest.
I imagine I’ll lose a few kts at 10.5 gph putting us very close.

Cheers
 
Interesting.

This is new to me. So flaps 0 instead of -3 above 10K? What type of changes are you seeing?

Thanks,

I see a knot or three faster. Try either config on your airframe, give it a minute or two for the autopilot to retrim.
 
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