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RV-9A performance questions

A

ALMARTON

Well Known Member
Hi folks,

I am almost receiving my RV9A that is being built professionaly for me (I don't have time and think I lack competence for doing it myself....)

I am writing to ask help from you that already built and have experience with the RV9A, mine will be equipped with XIO-320-D1A (160 Hp) and a constant speed propeller Hartzell HC-C2YL-1BF/F7663-4.

For this characteristics I would like to know from your pratical knowledge and experience (once I could not get the information anywhere else or when I got it was incomplete or differs slightly from the ones I can find on Vans site )... so I ask what would be:

a) Vx (Best angle of climb speed) ?

b) Vy (Best rate of climb speed) ?

c) VANS states that Cruise [75% @ 8000 ft] TAS would be 186mph for this configuration , is that attainable or too optimistic (in that case what you often/easily get on yours) ?

d) Vs0 (stall speed full flaps) ?

e) Average rate of climb you get gross weight

f) For this horsepower (160hp) are your take offs often shorter than landings?

g) And finally if anyone has RV9As performance charts (for altitude density) or any extra data if possible please send to my email: [email protected]

I appreciate all the help in advance and the possibility to compare all data from different owners/builders for the same aircraft.

Many thanks
Alexandre Marton
Brazil.
 
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Alex,
First, congratulations on your new aircraft. I'm sure you will enjoy it.
As to your questions, all I can say is that the manufacturer of your aircraft should provide you with that information since each aircraft will be slightly different. I would expect the manufacturer to perform all flight testing required to establish these numbers prior to delivery and should be part of the aircraft POH.
You cannot use any of Van's numbers since he doesn't give any for the 9/9A using 180HP power plant.
 
Sorry, my mistake the power plant IO-320 is 160 horsepower, my bad...

Despite each aircraft having small diferences I would enjoy comparing numbers from your experiences...

Thanks.
Alexandre.
 
The one drawback to the 9?

I was talking to a nine driver the other day. I expressed some jealousy at the long wing that is better at altitude than my 6 hershey bar wing. He agreed but said the you really noticed the loss of 20 HP at altitude, that climb rates are like 300 fpm at 12,000 feet.

Turbo or 180 HP might be good, just watch the VNE.

Hans
 
The problem with turbo is NOT VNE (this you can see) the problem with turbo is TAS (that you can't see and hence easily disregard utill too late). Please read it (very important):

http://www.vansaircraft.com/pdf/hp_limts.pdf

Thanks for the info on the 300fpm at 12.000ft, please I encourage others to reply to this post with your numbers from your pratical experience. At least it will be nice to compare but I also think it would give us good statistic data about differences and skill in building this wonderful aircraft.

Regards
Alexandre.
 
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nucleus said:
... He agreed but said the you really noticed the loss of 20 HP at altitude, that climb rates are like 300 fpm at 12,000 feet.
...
Click to expand...
That can't be right. My 135 hp RV-9 was still going up at an easy 700 FP at 10,000 feet with me, my wife, and a bunch of bags in the back. (I can't wait to see how it does on 180 hp. Any day now.)
 
ALMARTON said:
Hi folks,

I am almost receiving my RV9A that is being built professionaly for me (I don't have time and think I lack competence for doing it myself....)
Click to expand...

Before anyone jumps on this, note that he is located in Brazil, were hiring a professional builder is legal.

Also, the RV-9(A) can be flown as an LSA (or the Brazilian equivalent) down there while the -7, -8, -10, etc. need a full pilot's license.
 
-9A flight test data

Having recently finished the flight testing of my -9A, with the same configuration you have, you can see my numbers here:
http://www.mykitlog.com/users/category.php?user=n539rv&project=161&category=6002

At 17,500 ft I was still climbing 500 fpm, using 2600 rpm.

Keep in mind that IAS can be different from plane to plane based on pitot/static installation.
My stall IAS is:
No flaps: 60 mph
20 deg: 55 mph
Full flap: 50 mph

Determining Vx & Vy accurately is totally dependent on stable data collection during constant changing flight (climbing at stable power and airspeed). I found the numbers I determined are very close to Van's published numbers, so I went with what they determined, trusting their flight testing skills over mine.

Do read through my flight test logs shown above.
 
I agree with Bill - those climb numbers cannot be correct. My 9A is still climbing at 800+ fpm at 17500 elevation (I do have the 180 HP engine).

As a reference point, my numbers are very similar to Mikes for stall. And my Vx is about 76 mph and Vy is 96.

I can easily get 180 mph cruise at high altitude but I often throttle back from that a bit to save fuel. I recently flew Reno-Denver-Reno and averaged 30 mpg for the trip.

Typical climb (sustained) at gross for me is around 1000 fpm, but I have a 87-inch cruise prop, so climbing is not what my airplane does as well as some others. (still way better than spam cans)

Have fun with your new toy!

greg
 
Spooky stories

The flutter articles linked above. Airplanes do fall apart when their physical limits are exceeded but I find the logic "adjusted" in the story to fit the needs of the writer in a given part ignoring the logic expressed in other parts. It's OK to scare the builders and fliers of your product away from flying too fast but the facts are very thin and not completely presented. OK so it's just a spooky story, don't confuse it with what really happens - it certainly isn't explained here.

Bob Axsom
 
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