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Is my RV3A Slow?

R

RayJr

Active Member
Hello,
Seems you guys talk about higher speeds than I see. At 2700rpm / 7600 DA, I was seeing 159 TAS. Does that seem slow to you? I have an O320 with an after market Injector - The previous owner said 160hp. And a Catto Prop. Not sure which pitch but Catto website says they'll all do the same top speed just at different RPM. This occurred at 1150 pounds.

What are your top speeds? Does it make sense I'm only getting 159?

Thanks

Ray
 
RayJr said:
Hello,
Seems you guys talk about higher speeds than I see. At 2700rpm / 7600 DA, I was seeing 159 TAS. Does that seem slow to you? I have an O320 with an after market Injector - The previous owner said 160hp. And a Catto Prop. Not sure which pitch but Catto website says they'll all do the same top speed just at different RPM. This occurred at 1150 pounds.

What are your top speeds? Does it make sense I'm only getting 159?

Thanks

Ray
Click to expand...
What is your INDICATED airspeed at 7500 feet? How are you converting to TAS?
 
My RV3b with 160 hp and sensenich metal prop pitched 81" gives an indicated TAS of 172 mph at 7500' and 2300 rpm , according to the AV30 with temperature probe. I may be wrong on the pitch and vaguely recall 83" stamped on the prop during removal and inspection.
Passing by the same towered airport within a couple of hours, east at 7500' and west at 8500' enquired my tracked speed on their end. In both cases the tower operator replied 160 knots (184 mph) I don't know engine rpm at the time, but normal cruise RPM is never greater than 2350 rpm.
 
Richard RG said:
My RV3b with 160 hp and sensenich metal prop pitched 81" gives an indicated TAS of 172 mph at 7500' and 2300 rpm , according to the AV30 with temperature probe. I may be wrong on the pitch and vaguely recall 83" stamped on the prop during removal and inspection.
Passing by the same towered airport within a couple of hours, east at 7500' and west at 8500' enquired my tracked speed on their end. In both cases the tower operator replied 160 knots (184 mph) I don't know engine rpm at the time, but normal cruise RPM is never greater than 2350 rpm.
Click to expand...
Indeed, That is faster than mine. At 2300 I'll see about 155mph/135knots true.
 
The first step is to verify the accuracy of your pitot/static system.

See these excellent articles by Kevin Horton --
https://www.kitplanes.com/flight-testing-static-system-error-theory-and-practice/
www.kitplanes.com

Flight Testing: Static System Error - Theory and Practice, Part 2

Kevin Horton, data analysis, flight-test program, RV-8, www.vansaircraft.com, Van's Aircraft, Jim Weir, ASI, calibrate, instrument error, Dynon, www.dynonavionics.com, D-10A EFIS, D-10A, EFIS, Dynon D-10A EFIS, flight testing, constant wind direction, OAT probe, fresh air scope, calibrated...
www.kitplanes.com www.kitplanes.com

You may discover that your airplane performs just fine...and the "problem" is in the size/shape/location (or some combination of all three) of the static ports.

Good luck!

B
 
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