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09-13-2011, 11:47 AM
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Join Date: Aug 2010
Location: Wichita, KS
Posts: 1,958
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How far below your expectations is 152 knots TAS on a 160hp O-320 with c/s prop?
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09-13-2011, 12:29 PM
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Join Date: Jan 2006
Location: Belgium
Posts: 645
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160 KTAS
Full throttle, max RPM, leaned for max. power (ROP), you should see approx. 75% and 160 KTAS.
Mine does 152 KTAS at that altitude, @ 2350 RPM, LOP (approx. 60% power) and "sips" about 25 ltr/hr.
Doing 161 KTAS (@ 2600 RPM, ROP) it will "slurp" 36 ltr/hr. Guess what my usual cruising speed is............
I see about 1/4" to 1/2" of the counterweights above the stabiliser, depending on the loading, but have not bothered to change anything because the fairing will no longer fit and I will have to redrill the holes in the front brackets of the elevator and make slotted holes....... ouch! (how did you do that?) Now that you confirm it does not make any difference anyway, I am not even tempted anymore.
Regards, Tonny.
__________________
"Pilottonny"
Tonny Tromp
Lanaken, Belgium (EU)
RV9A, Registration: PH-VAN
ECI-Titan IOX-320 with dual EI, turning a Whirlwind 200RV CS prop.
Sold
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09-13-2011, 02:26 PM
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Join Date: Mar 2010
Location: Long Island NY / Ft Myers FL
Posts: 65
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Expected performance
Looking at Van's specs, I should see some 169kts. That number corresponds with what other people have posted and from some other RV9A pilots I have spoken with.
I don't plan on flying those numbers, but if I'm not getting those numbers at max performance, it means I am not getting the performance/efficiency I should be getting at my cruise settings. At 23 square, I typical see mid to upper 130kts TAS
Mark K
RV9A
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09-13-2011, 02:31 PM
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Join Date: Aug 2010
Location: Wichita, KS
Posts: 1,958
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Wow, I didn't think there was any way I'd REALLY end up with a 160 knot airplane, as planes can often fall far short of manufacturer claims. But you guys have me excited now. I'll be watching this thread with great interest.
Mark, best of luck with your efforts!
__________________
Kurt W.
RV9A
FLYING!!!
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09-13-2011, 05:36 PM
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Join Date: Apr 2009
Location: Ipswich QLD Australia
Posts: 245
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Mine too!!
I just noticed the other day that in level flight, my counterbalance arm was about 1" above the horizontal stab. Mark is saying don't bother, and if it does not change anything I can understand that, but should I add another shim to adjust that.
I've only got a 0-235 with fixed pitch prop, and I would love to see figures that Mark is getting. Our 9a only has 31 hrs on the hobbs, and the wheel pants and leg fairings haven't been fitted yet. Until they have been fitted I haven't been concerned about the performance figures.
Bob
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09-13-2011, 06:14 PM
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Join Date: Mar 2005
Location: Ramona, Ca
Posts: 259
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Mark,
JMHO but, I think your expectations are a little high. Looking at Van's specs. for 75% power @ 8000ft I see 187 mph solo or 162.5 kts TAS. The 169 kts is Vmax at sea level I think. You're not far off from Van's numbers.
I normally see in the 160-162kts TAS range at ~8000 ft with fixed pitch and a little less than 2600 RPM. I have to pull the black knob back a bit so as to not exceed the prop RPM limit.
Bill 
__________________
Bill RV-9A Flying
FFI- Flight Lead
N99WC
Ramona, CA (KRNM)
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09-13-2011, 07:29 PM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
Originally Posted by BillC
Mark,
JMHO but, I think your expectations are a little high. Looking at Van's specs. for 75% power @ 8000ft I see 187 mph solo or 162.5 kts TAS. The 169 kts is Vmax at sea level I think. You're not far off from Van's numbers.
I normally see in the 160-162kts TAS range at ~8000 ft with fixed pitch and a little less than 2600 RPM. I have to pull the black knob back a bit so as to not exceed the prop RPM limit.
Bill 
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Your numbers are about right, Bill.
I think Mark could come up close to 160 if he ran at best power, about 100 ROP. For sure that's how Vans does it.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
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09-13-2011, 07:32 PM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
Originally Posted by mark960
Looking at Van's specs, I should see some 169kts. That number corresponds with what other people have posted and from some other RV9A pilots I have spoken with.
I don't plan on flying those numbers, but if I'm not getting those numbers at max performance, it means I am not getting the performance/efficiency I should be getting at my cruise settings. At 23 square, I typical see mid to upper 130kts TAS
Mark K
RV9A
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At 100% power you may see 169, Mark. You won't see it at 8000' where max power is about 75%.
If you have an EGT system, set 100 ROP and see how it rolls at that setting.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
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09-13-2011, 07:33 PM
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Join Date: Mar 2010
Location: Long Island NY / Ft Myers FL
Posts: 65
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BillC
You are right, I was wrong. I was reading Top Speed not the 75% at 8000, which is the most power you can get at 8000. (without a turbo). So.... it looks like I am not that far off of where I should be.
Now I am only looking for the missing 7 knots. ie... It's probably one or more small items that need to be tweaked.
Mark K
RV9A
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09-14-2011, 10:58 AM
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Join Date: Aug 2006
Location: St. Louis, MO
Posts: 162
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Off topic, Vlad, but I love the picture of NYC in the background!
Jim Bower
St. Louis, MO
RV-6A
N143DJ (flying...finally)
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