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Performance RV-9

stefan87

Member
Hi,

I am an RV builders from Europe from Austria.

I would be interested in the following of you very much:

Motorized How you at? (O-320, IO-320, O-360, IO-360 (180HP, 200HP)
How are your climbing performance?
What are the cruise performance?
And what is the consumption?

I have heard that the RV-7 (180 HP) in the cruise should be almost equal as an RV-9 (160hp). Is that true?

Yours sincerely,

Stefan
 
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Hi,

I am an RV builders from Europe from Austria.

I would be interested in the following of you very much:

Motorized How you at? (O-320, IO-320, O-360, IO-360 (180HP, 200HP)
How are your climbing performance?
What are the cruise performance?
And what is the consumption?

I have heard that the RV-7 (180 HP) in the cruise should be almost equal as an RV-9 (160hp). Is that true?

My (0-360) 180 HP RV6A is close to 20 mph faster than a 160 equipped 9A. We both have C/S props. I can also climb faster. But the 9A with a 160 does rather well in climb. We fly out of airports in the 4600' elevation range, and usually fly between 7500 - 9500' msl.

The 9A with the 160 does well on fuel consumption. However, if I fly slower for best fuel management, I can usually do as well. I just don't like flying that slow.

I have not flown my 6A against a 7 for enough time to really evalute the differences between these two. I just know that the 6 is quite close to the 7 performance wise.

L.Adamson
 
Stefan,

A lot of this depends on the configuration of the airplane, particularly whether you have a CS prop or not. As a data point, my 9A has an IO360 with a FP Sensenich prop, pitched for cruise (87 inches). Maximum climb rate is about 14-1500 ft/min between 6000MSL and 10000 MSL - not as good a some, but that's with a cruise-pitched prop. My WOT speed at 8000 feet density altitude is just at 200 mph (~2740 rpm).

greg
 
Thank you for the very fast replys.

And what are the consumption of the:
O-320 inm an RV-9
and the IO-360 (180HP or 200HP)

at thge same cruise speed?

tanks

Stefan
 
My RV9 with O-320, wood cruise prop, 2300rpm, leaned out in cruise flight burns not much more than 7 gallons/hr (6.8 to 7.2). I plan my trips using 140kts GPS ground speed as my preferred speed. Climbs are 1500fpm but on hot days I shallow to 500fpm after initial climb to keep CHTs in check.
 
Fuel burn on my IO360 at 165 mph cruise and leaned properly at 10,000 ft (more or less) is about 6.5 US gallons/hour. My engine is nominally rated at 180 hp and I burn both 100 LL and premium mogas depending on which is available. I see no noticeable difference in performance between the two fuels.

During climb I can burn as much as 12-14 gph. Good thing it gets to altitude rapidly!

greg
 
RV-9a numbers

I bought a very straight, AME-built -9a.
It has all fairings.
low-time 0-320 7.5:1 compression
carburetted with magnetos.

I'm sure everyone's numbers are correct, but for some reason, I don't see the performance some other do.

at 5000' and 2300 rpm, cruise is about 125 kts. at 7 gph.
I have a mild 'climb' prop, metal sensenich, 70 x79 but only see 1000 fpm climb on average, lightly loaded, whether at 75 or 90 kts.

hope this is helpful.
 
Thank you for the very fast replys.

And what are the consumption of the:
O-320 inm an RV-9
and the IO-360 (180HP or 200HP)

at thge same cruise speed?

tanks

Stefan
Stefan,

Van's only recommends the O-235, O-290, & O-320 for the -9. However, some have put the O-360 on their -9's but I have not heard of anyone installing a 200 hp engine on the -9.

My -9 w/ a 135 hp O-290-D2 would climb at around 1800 FPM with a fixed pitch climb prop on it and cruise at 140 knots/165 mph on 6.5 gph. At gross it would do about 1250 FPM, if I really pushed it.

I'm in the process of replacing that engine with a 180 hp O-360 but will continue to run a fixed pitch prop.
 
Today I took my plane on a speed run. At 2700 RPM and 8000 DA, I was about 3/4 throttle 71% power and 151 KTAS (174MPH). I feel that this is a bit slow. My fuel burn was about 8.2gph. I had bkn cumulus clouds at my alt so I had to maneuver around a bit. I am going to re-run, but with about 1-2" of throttle left I am thinking that my Catto prop is pitched more for climb. I will say this plane climbs REALLY well. 1900 FPM is no problem and if I climb at Vx I will see 2400. I'd rather have top end though.

Anyone have any thoughts on my performance numbers. Seems slow? I can live with it, but I'd really think that I could get WOT at 8000 DA and be at 2700 RPM?

at 2400 RPM I am about 135 KTAS 2500 about 140
 
seems right

Your analysis that is.

It is slow and I would say that the prop needs more pitch.

My '9 has a 160hp O-320 and a Hartzell.
At 8000' DA, Wide Open Throttle, 2500 rpm, I can lean nicely and generate 161-162 knots True at 8 gph. This is very repeatable.

You ought to see it climb with the constant speed.:D
 
Following is from four years ago. I did the test at 8,500'. My propeller is placarded not to run over 2,600 rpm.

airspeed.jpg


Configuration at the time:

O-320, 160 hp, carb, 2 mags
Standard fixed pitch Sensenich propeller: 70CM7S9-0-79
empty weight: 1084 lb
polished aluminum, primer on fiberglass parts
wheel pants and fairing on

Now I usually cruise between 8-10k, at 65% power it does 140+ and burn less than 7 gph. Since conditions are different I can not give a single performance number. I know other 9As with better performance than mine. Mine is a little heavy and not perfectly built.
 
Catto Pitch?

Tony,
I'm curious about your speeds. I have a Catto 3 blade ready to go on my 9A and am wondering if you have Craigs' recommended pitch for a 9A with 160HP or did you have him do someother pitch? I can't remember what it is off the top of my head but he was sure when I got mine that it would generate at least Van's numbers.

Thanks
 
Tony,
I'm curious about your speeds. I have a Catto 3 blade ready to go on my 9A and am wondering if you have Craigs' recommended pitch for a 9A with 160HP or did you have him do someother pitch? I can't remember what it is off the top of my head but he was sure when I got mine that it would generate at least Van's numbers.

Thanks
Paul, I told Catto what I had he said he would pitch the prop for 191mph. I am no where near that. I have sent him a message and and waiting on his reply.
 
My Last Test

Hi Tony,

I sent mine back to Craig last year for a re-pitch. I did a WOT GPS test before and after. What I can say is that it didn't change.... When I got the prop back and tested it using the three way GPS method, the results were the same. 161 kts at 2700 ~ 2730 RPM with the DA at 11,500. (don't currently have % power #'s coming soon) My fuel burn is in the same vicinity, though a little less at the higher altitudes.

I would agree with you about the climb pitch. It climbs very well. Something I've noticed flying with my CS friends (6A's). If we are in cruise they will leave me behind unless they pull some power. If we start into a climb configuration (to get over the rocks) I will gain on them and pass them unless I pull some power off! How much of this is wing efficiency at higher altitudes or the prop? I'm not an aerodynamics expert so I can't say.

The Catto still remains about 5 kts faster than the original Sterba prop. I do think it could be pitched more. When I'm at sea level I've got almost half of my throttle pulled... fixed pitch props are always a compromise.

Today I took my plane on a speed run. At 2700 RPM and 8000 DA, I was about 3/4 throttle 71% power and 151 KTAS (174MPH). I feel that this is a bit slow. My fuel burn was about 8.2gph. I had bkn cumulus clouds at my alt so I had to maneuver around a bit. I am going to re-run, but with about 1-2" of throttle left I am thinking that my Catto prop is pitched more for climb. I will say this plane climbs REALLY well. 1900 FPM is no problem and if I climb at Vx I will see 2400. I'd rather have top end though.

Anyone have any thoughts on my performance numbers. Seems slow? I can live with it, but I'd really think that I could get WOT at 8000 DA and be at 2700 RPM?

at 2400 RPM I am about 135 KTAS 2500 about 140
 
I just received my re-pitched prop back from Catto. Here is a current screen shot. This was at W.O.T. 8kDA and full fuel and just myself.

2ibkgg4.jpg


Here is the screen shot of prior to the re-pitch. Notice the high RPM compared to the current shot.

pw1ad.jpg
 
Here is a picture that most pleases me. I switched back to KTS for my airspeed. Notice the 156 KTAS at 2550 RPM. Before my re-pitch I would have to run 2750 to get that. So far so good. I will try to post some pictures on my blog later of the nickel leading edge retrofit.

n66vzl.jpg
 
Tony, looking great.

I like that the first two pictures show that before you were using 11.3 g/h and the after pictures shows that at the same speed you were using 8.1 g/h.
I know the flight conditions were a little different, but it is looking good.

Kent
 
I like that the first two pictures show that before you were using 11.3 g/h and the after pictures shows that at the same speed you were using 8.1 g/h.
I know the flight conditions were a little different, but it is looking good.

Kent

Hi Kent,

Yep, the first photo I wasn't leaned at all. One of the natural by-products of turning 2900 RPM was high CHTS and EGTS. It was also a hot day. Re-pitching my prop in part was desirable so that I could see my temps come down. So far, so good for that.

I am thrilled with my RV-9.
 
Thats great Tony, now show us your nickel leading edge on your prop.

Hey Todd, lets go flying on Saturday. I will get some prop photos up soon. I only had my phone yesterday and it wouldn't have done the prop justice. It really looks good.
 
RV-(A with 200HP

Van's doesn't want 200HP on the 9A's, however, I have installed an Eggenfellner E6/200 which is only rating that kind of power at 2700 rpm. My takeoff setting is 2500 and cruise is usually 1900 to 2000rpm. The prior engine I had was a max 160HP Egg H-6 and I would get 130kts every time with those low cruise power settings. At 12,500 I got the gph down to 5.9. at 1900.

I will post my performance numbers this week once I get them together. Using a brand new three blade MT.

- Aaron
Austin TX
 
Those of you flying the tailwheel -9, I am looking for comparisons for Vx and Vy and Best Glide. I have done several tests and get different numbers each time. Just curious what your flight test numbers are?

Right now I have Vx at 64 KIAS and Vy KIAS at 75 KIAS BG at 75 KIAS.
 
Those of you flying the tailwheel -9, I am looking for comparisons for Vx and Vy and Best Glide. I have done several tests and get different numbers each time. Just curious what your flight test numbers are?

Right now I have Vx at 64 KIAS and Vy KIAS at 75 KIAS BG at 75 KIAS.

Tony-
I agree with getting different numbers. I don't yet have an autopilot installed so that makes it a bit difficult as well. I've always understood that Vy and Vglide should be about the same, but can't confirm that in my tests. In short I would not recommend anyone take my numbers as gospel.

That said, the numbers I use: Vx about 65KIAS, Vy about 85KIAS, Vglide = 75-80.

What I think I've found with the lack of consistency in my numbers (mostly Vy and Vglide) is that there very well may be a wide range here (i.e. a very flat part of the curve) that we are dealing with. I too though would be very interested what the "average" may be among a wide variety of 9/9A's. I would bet that would get us close to the ideal, at least for those of us you are using the recommended 160-hp. I suspect combining the 160hp numbers with the occasionally used 180hp numbers would not be very helpful toward this end.
 
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Thanks Steve,

I am looking at the CAFE RV9A testing. They came up with 95MPH (82KTS) Vy and 82 MPH (71KTS) Vx.

*"Vy, speed for best climb rate, CAS, 5500? dens.alt, @103 mph TAS 95 mph.

Vx, speed for best climb angle, CAS, 5500? dens., @88.3 mph TAS 81.6 mph"


Interesting that they found the best descent rates at 82 MPH (71KTS)
"Min. sink rate, idle power, coarse pitch, 1725 lb, 81.7 mph TAS 664.2 fpm" and the best Glide at 95MPH (82kts) 12:1

http://cafefoundation.org/v2/research_aprs.php
 
Yeah, I just looked that up too, Tony. Interesting. I maybe flying Vx and definitely best glide 5 or so knots too slow. Otherwise am pretty close. Need to get the autopilot servos installed. I can't hand fly well enough to get repeatable numbers.

BTW, good to have you in this part of the country. Look forward to meeting up finally!
 
Definitely let's get together. I am loving the PNW!

My original numbers were close to the CAFE numbers, but started doing some testing again recently as my prop is pitched differently and W&B different than my flight testing basis. I think I will stick with the CAFE till I get some good science.
 
For what it's worth, my numbers are Vx=76 mph, Vy=92 mph. That's with the IO360. I absolutely agree that it is difficult to get consistent numbers hand-flying this stuff.

Greg
 
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