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Comparing the 9a to 7a

Poolecw

I'm New Here
I'm debating the two models. I know the 7a has aerobatic capability while the 9a is boasted to be more of a cross country flyer. What makes other 9a more of a country machine than the 7a? I realize the physical specs are different as well. But aerobatics aside, what sets the two apart?

I guess what I'm most interested in are the real world performance numbers: fuel burn, useful load, and TAS. Ease of construction also.

Primary missions are both putting around the local area as well as weekend getaways for the wife and me
 
I'm debating the two models. I know the 7a has aerobatic capability while the 9a is boasted to be more of a cross country flyer. What makes other 9a more of a country machine than the 7a? I realize the physical specs are different as well. But aerobatics aside, what sets the two apart?

I guess what I'm most interested in are the real world performance numbers: fuel burn, useful load, and TAS. Ease of construction also.

Primary missions are both putting around the local area as well as weekend getaways for the wife and me

The wing is a really big difference. Also the aileron shape makes for quite a bit stiffer (slower) roll. You'll generally find fuel burn per TAS to be about the same. "Ease of construction", exactly the same.
 
The wing is a really big difference. Also the aileron shape makes for quite a bit stiffer (slower) roll. You'll generally find fuel burn per TAS to be about the same. "Ease of construction", exactly the same.

The horizontal stab is also different with a Roncz airfoil like the wing and also like the wing, a higher aspect ratio. The wing is 4 feet longer than the 7 and the chord is less than the 7. This results in lower induced drag, hence the altitude performance at the expense of aerobatics. The fuselage and cabin are identical. The wing attach area is slightly different of course due to the narrower chord.

All that said, the 9 loves altitude and that is where it shines. For the same power on each plane, the 9 is more fuel efficient and even slightly faster at high altitudes than the 7. The IO-320, 160 hp is perfect on the 9 and is the engine preferred on it by Van's but the 360 is the better overall engine on the 7 (I think, anyway). I have the 9 but have flown the 7 and the 6 a lot. Mine has the IO-320 and weighs 1084lb. It is not particularly slick. I fly it as high as is practical and on a recent trip of 600 miles had 178 mph TAS at 11,500 ft, 6.6 gal/hr. I can easily do 185-190 if I want to burn more fuel.
Ed
 
RV-9A is the best airplane I have ever flown in all respects except one. It is not as high on the 'fun factor’ as the aerobatic RVs and Rocket.

When I went shopping for a new airplane to build, I had a spec: a high wing RV-9 with big tires. That adds in a different type of ‘fun’.

V
 
I can't comment on useful load, but a couple of other observations:

You'll feel turbulence a little more in the -9. And I found the -7 a little easier to land...the -9 will float more, especially with an FP prop. No big deal once you're used to it, but it's doubly important to have a low idle speed.
 
Very simple answer

I've flown my 9A for almost 900 hours in the past 5 years. In that time about 600 of those hours were side by side with a 7A. Both have IO-360's, the 9A has a constant speed prop, the 7A is fixed pitch.

We consistently have almost identical numbers from a fuel burn perspective. He burns less at lower altitudes and I burn less at higher altitudes. I climb faster due to the CS prop. I think he could out run me but we have never had a race. All of our cross country (and we have done a lot of it) is done at an average of 150kts TAS side by side.

So its really an easy answer to your question. If you want do aerobatics of any type get the 7A. If you want to get the best cross country efficiency at supplemental oxygen altitudes get the 9A. Otherwise either plane will delight you immensely!
 
Thank you for the Great replies. One question though, how do their useful Loads compare?

You can find this information on the Vans Aircraft web site. The factory airplanes are built ‘Vans way’, e.g., minimal avionics, no sound proofing, etc., so they tend to come in lighter than many builders’, but on the other hand the numbers are honest-if you build it that way, that’s what you’ll get.
 
Thanks for the comments everyone. I've also gone back through several very long threads on the subject but wanted to get some fresh opinions.
 
Perhaps I am wrong here but I chose the -7A as it appears to be faster. I have heard most guys plan 160-165kts in cruise where most guys in a -9A seem to plan 155kts ish? Correct me if I'm wrong here guys. If my recollection is correct I don't understand why the -9A would be preferred for cross country flight. When I think of cross country I think of quickest method but that's just me... Others may certainly vary.
 
Perhaps I am wrong here but I chose the -7A as it appears to be faster. I have heard most guys plan 160-165kts in cruise where most guys in a -9A seem to plan 155kts ish? Correct me if I'm wrong here guys. If my recollection is correct I don't understand why the -9A would be preferred for cross country flight. When I think of cross country I think of quickest method but that's just me... Others may certainly vary.

Depends on the airplane and engine/prop combination. I flight plan low-160's up to about 13k altitude, and high 150's above that - but the fuel flow at altitude is amazing.
 
145kt-150kt true

I plan for 145kt, but usually get average of 148kt true burning close to 7.5 gph (as I get better at leaning and managing the CPI2, 7.0 gph is my new norm) LOP down low (<8000’ da) turning 2420-2450rpm at 22.3-22.5 in MP. That doesn’t sound fast, but it covers ground cheaply, and in style. :cool:
 
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Thanks for the comments everyone. I've also gone back through several very long threads on the subject but wanted to get some fresh opinions.

I bet the responses are very much the same as previous threads.
Best way for you to form your opinion to which model is best for you would be to get a ride in each & let your hands (& butt) decide!
One thing this thread illustrates is that no matter which model the respondents chose, they love the performance of THEIR RV!
 
Depends on the airplane and engine/prop combination. I flight plan low-160's up to about 13k altitude, and high 150's above that - but the fuel flow at altitude is amazing.

Very nice, although your beast of an engine :D is somewhat of an exception to the -9A norm. haha
 
Very nice, although your beast of an engine :D is somewhat of an exception to the -9A norm. haha

Agreed - but it sure is nice for climbout with that constant speed prop. I took off a week ago in 90-degree temps with two butts in the seats, about 80 pounds in the baggage compartment and 42 gallons of fuel onboard - and 13 minutes after engine start I was climbing through 11,000 on my way higher.
 
Perhaps I am wrong here but I chose the -7A as it appears to be faster. I have heard most guys plan 160-165kts in cruise where most guys in a -9A seem to plan 155kts ish? Correct me if I'm wrong here guys. If my recollection is correct I don't understand why the -9A would be preferred for cross country flight. When I think of cross country I think of quickest method but that's just me... Others may certainly vary.

A valid comparison of the two models requires making all things equal other than the airframe.

The web site performance specs show the RV-7A to have a 3 MPH speed advantage over the RV-9A, at 8000' DA at 75% power, if they both had the same 160HP engine and prop.

Take the same two airplanes to 14,000' and the RV-9A would likely be just a bit faster than the 7A.

An RV-7A with a 200 HP engine will of course have the capability of being faster than a 9A with 160HP, in all air conditions.
 
Agreed - but it sure is nice for climbout with that constant speed prop. I took off a week ago in 90-degree temps with two butts in the seats, about 80 pounds in the baggage compartment and 42 gallons of fuel onboard - and 13 minutes after engine start I was climbing through 11,000 on my way higher.

Awesome performance Airguy. Curious, do you spend a lot of your cruise in the yellow band with that engine?

A valid comparison of the two models requires making all things equal other than the airframe.

The web site performance specs show the RV-7A to have a 3 MPH speed advantage over the RV-9A, at 8000' DA at 75% power, if they both had the same 160HP engine and prop.

Take the same two airplanes to 14,000' and the RV-9A would likely be just a bit faster than the 7A.

An RV-7A with a 200 HP engine will of course have the capability of being faster than a 9A with 160HP, in all air conditions.

Totally agree Scott, my thinking is based off the -9A which seems to usually have a 320 and fixed in it and the -7A having a 360 and constant in it. From what I have seen this seems to be by and large the norm on engine and prop combos. Would love to be corrected if this is not the case.
 
Awesome performance Airguy. Curious, do you spend a lot of your cruise in the yellow band with that engine?

Assuming you're talking about airspeeds here - and not really. Below is a very typical cross country cruise for me, for anything over a hundred miles or so. I do have to pull the power back considerably for a 1000'/min descent rate, about 13"-15" MAP to keep the speeds where they need to be.
 

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Assuming you're talking about airspeeds here - and not really. Below is a very typical cross country cruise for me, for anything over a hundred miles or so. I do have to pull the power back considerably for a 1000'/min descent rate, about 13"-15" MAP to keep the speeds where they need to be.

Awesome fuel burn at that speed. Thanks for sharing.
 
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