Van's Air Force
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Preliminary numbers...
- Thread starter N523RV
- Start date
vlittle
Well Known Member
For comparison, my RV-9A with all fairings and wheel pants installed, WOT at 8000' pressure altitude gave me 163-164 KTAS (187-189 MPH). This is based on several airspeed calibration tests, with corrections.
Other conditions: weight 1560 lbs, 22.0 MAP, 2590 RPM. Indicated HP 75%. Sensenich fixed-pitch, AeroSport O-320 (160HP) roller lifter engine.
Van's specification is 186-187 MPH, so it looks like I'm spot on.
FYI my Vs is 49 CAS and Vso is 43 CAS
Vern Little
Other conditions: weight 1560 lbs, 22.0 MAP, 2590 RPM. Indicated HP 75%. Sensenich fixed-pitch, AeroSport O-320 (160HP) roller lifter engine.
Van's specification is 186-187 MPH, so it looks like I'm spot on.
FYI my Vs is 49 CAS and Vso is 43 CAS
Vern Little
Response...
That is not at wide open throttle.
Which opens a can-o-worms and a whole 'nother topic of conversation, but to answer the questions... let's just say my static RPM is 2150 with a top end RPM of 2650. My prop is a bit over-pitched at 72" and I believe my intake system is limiting engine output.
Next time I fly, I'll get some numbers at WOT and maybe get my fairings installed for good.
That is not at wide open throttle.
Which opens a can-o-worms and a whole 'nother topic of conversation, but to answer the questions... let's just say my static RPM is 2150 with a top end RPM of 2650. My prop is a bit over-pitched at 72" and I believe my intake system is limiting engine output.
Next time I fly, I'll get some numbers at WOT and maybe get my fairings installed for good.
dedgemon
Well Known Member
Numbers
Folks,
My numbers are really closes to Verns. I normally see 161 KTAS at 8000' density altitude, WOT, and 2400 rpm on a Hartzell prop. If you turn if 2700 you see 2 or 3 more knots but I just hate to add the noise. 160 Horse Aerosport O-320.
I've also notices that the 9 (and probably all of the others) is picking up about 2 inches of impact manifold pressure. WOT at 8000' density works out closer to 80% power because of this than the 75% that we would see with ambient manifold pressure.
My favorite power setting for going no-where is as follows.
20 inches MP, 2000 rpm, leaned way back. I'll see 128 KTAS and 5.9 to 6.0 gallons per minute. Just crazy.
For reference for the Catto guys. One of my friends is flygin a 9A. He recently took off a Catto 3 blade and went to a Sensenich 2 blade. His impression is that the Catto was smoother but that the Sensenich is quite a bit faster. Don't know what quite a bit is exactly but he paid to do it.
FYI
Folks,
My numbers are really closes to Verns. I normally see 161 KTAS at 8000' density altitude, WOT, and 2400 rpm on a Hartzell prop. If you turn if 2700 you see 2 or 3 more knots but I just hate to add the noise. 160 Horse Aerosport O-320.
I've also notices that the 9 (and probably all of the others) is picking up about 2 inches of impact manifold pressure. WOT at 8000' density works out closer to 80% power because of this than the 75% that we would see with ambient manifold pressure.
My favorite power setting for going no-where is as follows.
20 inches MP, 2000 rpm, leaned way back. I'll see 128 KTAS and 5.9 to 6.0 gallons per minute. Just crazy.
For reference for the Catto guys. One of my friends is flygin a 9A. He recently took off a Catto 3 blade and went to a Sensenich 2 blade. His impression is that the Catto was smoother but that the Sensenich is quite a bit faster. Don't know what quite a bit is exactly but he paid to do it.
FYI
Catto vs. Sensenich
David,
Any chance of finding out more details about this, like prop pitch for the two propellers and climb and cruise speeds? This would be really interesting for those of us trying to decide between these two props.
Thanks in advance,
Mark
dedgemon said:For reference for the Catto guys. One of my friends is flygin a 9A. He recently took off a Catto 3 blade and went to a Sensenich 2 blade. His impression is that the Catto was smoother but that the Sensenich is quite a bit faster. Don't know what quite a bit is exactly but he paid to do it.
FYI
David,
Any chance of finding out more details about this, like prop pitch for the two propellers and climb and cruise speeds? This would be really interesting for those of us trying to decide between these two props.
Thanks in advance,
Mark
Build9A
Well Known Member
Mine #s are similar
Matthew: My cruise numbers are about the same as yours. 0-320 160hp, sensenich 2600 rpm limit. I noticed you were at 4500 ft. Take it to 8000 ft. and do it again. Here's where I always get confused, but I believe that WOT at 8000 ft. altitude will still be about 75% power. As you gain altitude RPM % goes down. So the correct 75% power TAS will be wide open at 8000 ft. Someone correct me if I'm wrong. So, Matthew, I believe that you and I are probably right on Vans numbers.
The lycoming power curve at altitude is as follows:
Altitude RPM Percent of H.P.
2500 2550 75%
3500 2575 75%
4500 2600 75%
5500 2625 75%
6500 2650 75%
7500 2675 75%
Matthew: My cruise numbers are about the same as yours. 0-320 160hp, sensenich 2600 rpm limit. I noticed you were at 4500 ft. Take it to 8000 ft. and do it again. Here's where I always get confused, but I believe that WOT at 8000 ft. altitude will still be about 75% power. As you gain altitude RPM % goes down. So the correct 75% power TAS will be wide open at 8000 ft. Someone correct me if I'm wrong. So, Matthew, I believe that you and I are probably right on Vans numbers.
The lycoming power curve at altitude is as follows:
Altitude RPM Percent of H.P.
2500 2550 75%
3500 2575 75%
4500 2600 75%
5500 2625 75%
6500 2650 75%
7500 2675 75%
