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RV-7 vs RV-6 flying qualities & other differences

GHRoss3

GHRoss3

Member
Van's website provides performance and specification differences between the RV-6 and the RV-7. There's not that much difference between the two models other than lighter gross weight, 4 gals of fuel, and smaller wing on the RV-6. What are the flying quality differences between the two models? Why the rudder height increase with the RV-7? Even though the spec pages shows identical sizes, are there differences in the cockpit size? I sat in my first RV-7 two weekends ago and found it smaller than I expected. Note: I've been lurking on this site for many years and am getting closer to either buying or starting the build process. I'm leaning toward buying a 180 HP RV7 or 6 tail dragger when I retire from the Air Force. Thanks,
George
 
The bigger tail on the -7 is for several reasons. First, to improve spin characteristics and reduce tail wagging characteristics. Also, to give more authority for handling the torque of larger engines.

IIRC, the cabin difference is a slightly higher canopy. The width is the same. There may be slight differences in cabin length.

The -6 allegedly handles marginally better, being a slightly smaller airframe. <Also, aren't there differences in how the TE of the ailerons are shaped?>

Van's website still has performance figures for the -6 based on the old (draggier) gear leg fairings and wheel pants. With the latest generation fairings, a -6 should be a few mph faster than an identically equipped -7 because of wetted area differences.

If you're looking for value, the -6 should be a better value if you can find one equipped the way you want.
 
headroom is from different seat ribs...

the -7 gets improved headroom over the -6 from a lower seatpan geometry achieved from a different seat rib from the -6.
 
There are at least two different 6 vertical stabilizer & rudder designs

Ken Knowles and I were finishing our RV-6As at the same time Mine is a smaller unbalanced design. His had the balance horn and was larger.

Bob Axsom
 
George, I've flown both models many hours....

...and my pick remains the -6/-6A models. I had 500 hours in my -6A, a lot of that transition training nearly 80 guys over a 5 year period. They handle like a very nimble sportscar, if the stick isn't too short...cut off by builders. In reality, you'd be hard pressed to determine what you're flying if you were blindfolded. They're both a delight!

Furthermore, the -6 and -4 are definitely the biggest bang for your buck and waaaay underpriced. There are quite a few on Barnstormers priced well below parts cost. It's a buyers market and I personally, don't see that changing anytime soon. Buy a decent, flying airplane and in time, as money allows, tweak it to your liking with maybe a glass screen, 430W for IFR, autopilot and so on.

Best,
 
I 100-percent agree with Pierre, both are great. I have only flow a couple -7?s and I really could not tell the difference between my -6A and the -7A?s.

But first I think you need to answer the build vs. buy question for yourself. There is a lot of info/opinions/advice on this subject if you do a search.

For me, I chose to buy because I could not build any faster or cheaper than an already flying -6A. I am adding my own touches to it as I go. I have the counterbalanced rudder, the updated rudder peddle arrangement, pressure recovery wheel pants, and have removed the center console on the panel. So, there is not much the -7 has over my -6A. The difference in price between the two buys a lot of fuel and a nice glass panel.

The good part about the -7 is that it is a pre-punched build, so it is a little more standard. This means you can get things like an interior package that fit right out of the box.

If you buy, I would go with the -6 and bring along a knowledgeable -6 builder. If you build I would go with the -7.
 
George...

1 major difference is the "legality" of flying aerobatics 2 up. The 7 is cleared for aeros to 1600lb, so with a 1100lb basic weight, and 350lb of people, you can fly with just over half tanks. The 6 is 1375lbs, so even if you can get basic down to 1050, you aren't going to do 2 up aeros with any fuel :eek:

Whether that affects you depends on your desire for 2 up aeros, and your attitude to that declared limit (valid to 6g).

I am sure you will get some opinions on here about that, maybe even the rumour about fuel weight not counting ;) and whether the 6 really is any weaker than the 7 is in this regard!

Andy
RV-8 G-HILZ
RV-8tors
 
Having flown both (and, incidentally, done two-up aerobatics in both) I have to say that there isn't a lot of difference between the two. The -7 I flew had an O-360, the -6's i've flown all had O-320's. The -7's were a little heavier, the -6's a little lighter. Both flew the same, for all practical purposes.

There are many people flying the -6 with an 1800lb gross, a few claiming they have letters from Van's authorizing it (although when pressed, nobody has been able to produce a copy of one).
 
If the 6 is smaller and lighter, how does perform with a 160 hp? Compared to the 7 with the 180?

Steve
 
They weigh roughly the same...

steve91t said:
If the 6 is smaller and lighter, how does perform with a 160 hp? Compared to the 7 with the 180?

Steve
Click to expand...

When equally equipped, empty weights are nearly identical. The 7 is a more modern design and has a bit more efficient airframe. Might see a touch higher cruise in the 7, but marginal.

I have flown both. The 6 has a slightly higher roll rate and might be a bit more touchy in the flair. If I could fly and land blindfolded I would not take a bet that I could tell the difference. Lots of previous posts and discussions on the topic.
 
JonJay said:
When equally equipped, empty weights are nearly identical. The 7 is a more modern design and has a bit more efficient airframe. Might see a touch higher cruise in the 7, but marginal.
Click to expand...

How is the 7 airframe more efficient? I'm building my -6A in the same hangar as a -7 is also going together, and excluding the placement of the third wheel and the canopy opening design (tip-up vs. slider) the only differences I see externally are :

1) The -7 has the larger counter-balanced rudder same as a -9. My -6a has a smaller counterbalanced rudder similar to a -8.
2) The -7 has the sheared wingtips; my -6a has the Hoerner style tips.
3) The -7 has a slightly wider span than my -6A.
4) The -7 has a flat bottom skin between the wing spar and the cowling where the same skin on the -6A matches transitions from flat behind the cowling to a slightly convex shape to match the dehiedral angle at the point where the spars enter the fuselage.


The same cowling, wheel pants, fairings, etc. are used on both.
 
One major difference not mentioned is the RV7 has the RV8 wings which include longer ailerons with crisper control characteristics.

Pat
 
No imperical data...

ChiefPilot said:
How is the 7 airframe more efficient? .
Click to expand...
Only from what I have been told from "engineers" who ought to know(hint) and my own experiences flying side by side. The 7 was designed, as the 8 was, computer aided. The 6 was pretty much designed by hand.

I am sure it is arguable.
 
Sorry pat, the oposite is true.

Pat Stewart said:
One major difference not mentioned is the RV7 has the RV8 wings which include longer ailerons with crisper control characteristics.

Pat
Click to expand...

The shorter winged 6 has a faster roll rate. If you have a chance to roll an 8, then roll a 6, you can tell the difference. You can search "roll rate" for the many discussions about this in the past.
 
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Yep! It's certainly arguable.

JonJay said:
Only from what I have been told from "engineers" who ought to know(hint) and my own experiences flying side by side. The 7 was designed, as the 8 was, computer aided. The 6 was pretty much designed by hand.
I am sure it is arguable.
Click to expand...

I know of nothing in the -7 design that would make it "more efficient" than the -6.
The primary purpose of the -7 was to make the kit easier to manufacture and easier to build.
 
Agreed...

Mel said:
I know of nothing in the -7 design that would make it "more efficient" than the -6.
The primary purpose of the -7 was to make the kit easier to manufacture and easier to build.
Click to expand...

Because I dont want to break my golden rule of never arguing with those wiser (Mel)! THere may not be anything behind it, but I was told the 7 had the benefit of some pretty sophisticated aerodynamic modeling software to assist in its design. Software that was not available when the 6 was designed. But, even if that is true, there would be no way of knowing without some extensive side by side testing of like machines...so, I retract that statement. (can I do that?):cool::cool:
 
JonJay said:
Because I dont want to break my golden rule of never arguing with those wiser (Mel)! THere may not be anything behind it, but I was told the 7 had the benefit of some pretty sophisticated aerodynamic modeling software to assist in its design. Software that was not available when the 6 was designed. But, even if that is true, there would be no way of knowing without some extensive side by side testing of like machines...so, I retract that statement. (can I do that?):cool::cool:
Click to expand...

RV-6's and -7's have been flying side-by-side for several years now, not sure why anyone would consider the -7 aerodynamically different from the -6. They are for all practical purposes the same airframe. The only software I am aware of that was applied to the -7 design was CAD which allowed match drilling of holes and computer generated drawings. This resulted in greater manufacturing and assembly efficiency, but not aerodynamic enhancements.

Consider your statement retracted. :) (except in the archives where it will live forever!!)
 
This is just speculation, but having a complete computer model would allow some very rapid iteration on design choices. If the 6 was hand designed, there would have been less iteration and more building. The design would have been finalized and moved on. Having the ability to optimize the design more on the 7 means that they could remove excess weight, shift this component slightly, shift that component slightly, etc. and still end up with essentially the same plane.
 
One advantage of the -7 over the -6 is if you break something. For the most part, -7 parts are plug and play. For example when my rudder was banged up in a hangar door incident I built up a new rudder and bolted it right on. The non-prepunched parts on the -6 make fabbing new parts a little tricker, although obviously still doable.
 
If you are inclined to build, go with the 7.

If you are inclined to buy and fly, go with the 6.

Either way you can't go wrong. These machines are a delight to fly.

I take off for any reason - today it was to search for that deer I hit on Sunday. No sign of hide. hair or it. Maybe a hunter picked it up, the season was open that day and the deer may have been on the run because of it. I've ID'd the exact spot where it came on the road and it is all brush and tall grass on both sides. The front license plate was missing and that's where I found it, pure luck I'd say.
 
Better....,

My $ .02

The RV6 is a little shorter than a RV7. so....The RV7 has better pitch stability.
The RV7 has more fuel. More Better!
The RV7 has longer ailerons, 4". Better roll rate.
The RV 7 has more head room, More Better...........
I have flown, and built two RV6s, one had 500 hours, and the second one had 998 hours when I let it go. I have some 125+ hours in RV7s .
I did not think the RV7 would interest me untill I had a chance to fly several and use them as my own airplane.
The RV7 is a Better airplane, hands down.
I did not think I would like it when it first came the out. Or that I would need the 'improvements' that the 6 does not have. But the RV7 is a Better all round airplane than the 6. It is easer to build as well.
 
Good arguments Jay. But for someone buying a 6 or 7, would you say that the typical higher cost for a 7 is worth it?

If someone were to give me my choice of a 6 or 7 aircraft, I would probably take the 7(A). But I bought a 6A.
 
Too bad the larger counter balance tails of the 7's just look over sized & not dimensionally correct...........compared to the shorter, sportier, and eye pleasing "classic" tail of the original 6's. :D

L.Adamson --- RV6A (classic tail)
 
price

Buying or building?
Buying, a flying RV ? A RV6 is my choice. Since money is a limiting factor.

If money was no factor??? I would own 2 Grumand F8F Bearcats
one to fly when the other is down for mantience,,, No RVs for this hipothetical bizzilionair
 
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Are you sure Jay?

Jaypratt said:
My $ .02

The RV7 has longer ailerons, 4". Better roll rate.
.
Click to expand...

I have not rolled a 7 but I have an 8 and my 6 rolls faster. I would assume a 7rolls just like an 8 or very similar. I searched the archives and this is a common opinion. Regardless, the difference is minimal and I would not make my choice on that alone.
I still prefer my 6, 'cause that's what I own!:)
 
landing gear

One other difference not mentioned...on the A models, the 6A sits a bit nose high on the ground and the 7A is almost level. Slight difference in taxi visibility, the 7 "looks" larger sitting on the ground and there may be some implications for rough surface operations but I don't want to cause thread creep!

Jeremy Constant
7A 90hrs, about to start my 1rst condition inspection!
 
Jaypratt said:
The RV7 has longer ailerons, 4". Better roll rate.
Click to expand...
You'd think so, but it has longer wings, too, which results in an overall slower roll rate.

Having rolled both, I would say the -6 feels like it's rolling faster... But the difference isn't large enough to consider as a serious factor. They're effectively the same for the type of flying the RV was designed for... "gentlemanly aerobatics" I think Van calls it.
 
Not too much larger span

Gents,

The RV-7's have a different wing tip design then the RV-6's. The new style angles out and adds about 6" per side. I doubt very seriously that this area adds any real performance improvements or degrades performance.

So the real effective span difference is about 1ft total.

I actually prefer the look of the old style tips over the batwings and the new style.
 
It is not just the tip, the wings are longer too. Wing span for a 7 is 25' versus the RV6's 23'. There is also more leg and head room available. I have flown a 6 for 2500 hrs and a 7A for 600 hrs. and would agree with most of the previous comments. The most notable differences for me are the 7's greater load carrying capacity due to the larger wing area and more favorable CG envelope and the better directional stability due to the much larger tail. Both are great flying airplanes and I love them both.

Martin Sutter
building and flying RV's since 1988
EAA Technical Counselor
 
tips

You can still order the origional wing tips. I like them much better, but that is a personal thing. I have installed the old tips on a lot of the new 7s and 8s
As for roll rate, I think the 7 rolls better but haven't timed it. Could be the 6 is faster, but with longer ailerons on the 7..................?
 
as i did transition training in a 6A and now fly the 7A a few observations:

- attitude on the ground is noticeably different. i personally like the level feel of the 7A better than the 6A which reminds more of some other piper etc... spam can. however i'm convinced, it doesn't help with the tipover/nosegear issue either.

- 6A wiggled/dutch rolled a lot more in cruise than the 7A does.

- 6A felt slightly more twitchy during approach, especially at higher gross weights.

- 6A needed more/heavier rudder during takeoff/go around/slow speed climb.

- both are great aircraft :)

- did barely notice a difference in roll between the 2.
my observation is that the rv tends to roll quickest at around 120kts. going faster doesn't necessarily produce more roll rate, despite close to or full deflection of the ailerons. also, roll rate is much more affected by fuel load in the wings and whether solo or a pax onboard. due to "normal" powersettings, one tends to fly quicker all the time, between 140 and 160KIAS. so if you want to really maneuver, try slowing down first. you'll be surprised how the aircraft will actually be more agile then.


rgds, bernie
 
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