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Build Differences from RV-6 to RV-7

skelrad

Well Known Member
Friend
I understand that the RV7 kits are produced differently than the old RV6 kits, but I'm not really sure what that means in the end to a builder. I've seen a number of barely started complete RV6 kits for sale for thousands less (like $10k) than a complete RV7 kit. I've always assumed I would just buy a 7 kit, but that's a pretty significant cost difference, so I'm kicking around the idea of going with a second-hand 6 kit now.

I know that the 7 is a more modern kit, in terms of it's CNC accuracy and the plans. What I don't know is how that really impacts a builder. Can someone explain to me how the build of one vs the other will change? I've heard all of the jargon about matched-hole drilling thrown around, but since I've never built a plane before, the reality of what that means for a day in the workshop is lost on me. :confused:

Save the money on a 6 kit and have a "tougher" build, or go with the newer 7 kit? That is the question.

Brandon
 
RV 6 or 7 kit

The major difference is the match drilled parts along with a different center section. This gives the 7 a higher gross wt. and a quicker build time. You don't need a jig for the fuselage as with a 6. It's like everything else you either spend the time or the money, your choice.
Walt....RV-6A
 
I'm building a 6A. The biggest difference between the two in terms of construction is that the airframe is largely prepunched on the 7, and skins are cut to shape and size. So, on a 6, for example, wing skins are prepunched (depending on year of the kit), but fuselage skins are supplied oversize, and the builder measures, lays out rivet lines, cuts to final dimensions, and fits and drills. From the 6 plans one could build the aircraft from scratch. Of necessity, all components and skins are dimensioned. On the 7 plans, many dimensions are not necessary, (the parts come to final dimensions), so are not even set out on the plans.
Once the airframe is done, there is not much difference (gear install,electrics, firewall forward).
Some parts are shared between the 6 and 7, like the sliding canopy.
The 7 is an easier build, but if you like building, and don't mind the extra work, certainly a 6 is very doable. There are lots flying and lots under construction.
Another point perhaps, is that because the 7 is prepunched and skins precut, the airframes are all identical, so if you ever have to replace a skin, the new skin from Van's will be identical to the old, so a somewhat easier replacement.
If you do decide to complete a 6, I suggest that you get the 7 manual and preview plan set from Van's - the 7 plans are helpful to building a 6, with more detail in some areas than the 6 plans, the canopy instructions are different and better even though canopy components are the same, and there are some additional plan sheets for electrical and firewall forward.
Bill Brooks
RV-6A
Ottawa, Canada
 
Having completed both a 6 and a 7, the comments are very accurate here, except don't REALLY be thinking the 7 is just an assembly project. You will still be building and scratching your head at times, but thankfully there's a lot of help out there, just like this forum.
All said and done, if you can afford it, get the 7. It is easier, and if you need to replace parts down the road, chances are that they will fit better.

Godd Luck to you.
 
Of course, you are correct in that there are a number of fabrication tasks in building one of the "current generation" RV kits (7,9, 10) but the percentage is much smaller than the "first generation kits" (3, 4 - I think the eight should be called generation 1.5).

Having said that, and my total experience being based on buidling a pre-punched RV-4 and then rebuilding it with pre-punched holes in the wing skins, only a masochist would opt for building a 6 over a 7 all other things being equal. Of course, all other things are never equal and the financial inducement for building a 6 over a 7 might sway the decision if your have more time than money and really like the joy found in building it yourself almost from scratch.

Either way you will end up with a great airplane - and how long it took you to get there will hardly cross your mind once the wheels break contact with terra firma.

I have no background to offer opinions on the relative merits of the flight characteristics of a 6 vs 7 but I imagine they are very similar and so much better than whatever you have probably been flying that any relative advantages of 6 vs 7 amount to noise level anyway. Of course, based solely on comments published here and elsewhere on the relative flight experience of the RV-4 vs all of them (save the -3) I'll enjoy my cramped cockpit and pure delight in playing fighter pilot in N144KT anyday...

Now if you want to talk cross-country IFR - I'd say the -9 or -10 is the ticket....
 
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6 versus the 9 for cross country

Now if you want to talk cross-country IFR - I'd say the -9 or -10 is the ticket....

Believe it or not....

With a two axis auto-pilot, and a blind-fold; you wouldn't be able to tell the difference between the 6 & 9 on a long cross country flight. And that includes turbulence. I've got a 6A, but a lot of 9A flight time; which is mostly cross country. A friend has built two 9A's, and has around 350 9A hours. We both agree on this point regarding the 6 versus the 9 for cross country. They simply don't feel different. I flew the 9A just a few days ago for conformation. :)

L.Adamson --- RV6A
 
differences

7 has higher Vne, designed for heavier engines, a bit more room (not a lot), I think more wing span (2 feet I think but I could be wrong)

Along with those differences mentioned they 6A looks considerably different than the 7A. The stance on the ground has the 6A looking smaller and with a greater static angle of attack with the 7A tail being much higher on the ground due to longer main gear legs. 7A is a higher step up to get onto the wing which could be significant if mobility is an issue.

Also bear in mind that the differences in build will pretty much end at the airframe. Don't discount the fact that SIGNIFICANT amounts of time will be spent on "systems" construction and assembly ie engine, instrument panel etc. There is little difference between the 6 or 7 there but it can be the majority of build time to do these systems, depending on engine and instrumentation.

I think one thing you should do is really look at the airframes on the ground and sit in them to help with the decision.

Jeremy Constant
 
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6 vs 7 build time

From discussions I have had with builders it would seam that a basic RV-6 will take approx. 2000 hrs to build while an RV-7 will only take approximately 1200 hrs. If you go for the quick build kit it will go down to 800 hrs (your mileage may vary). I can't tell you for sure what it actually took me to build my 6 because I never tracked build time.

This all said, if you can buy a well made RV-6 kit that is partially built up to the quick build stage it should not take much more time than a RV-7 kit to complete.
 
building time

Just a cautionary note: I agree that the ratio of build times between the 6 and 7 may be accurate and useful, but if you're like me you can be lead down the garden path with expecting to do it in someone else's amount of time.

I was in the position of "I don't know what I don't know" and my build is at 6 1/2 years and counting. I stopped counting hours when I realized that I felt like a failure when I passed the number I thought it would take and wasn't even 1/3 done! My wife reminded me that this was a hobby, not a race, and if my wildly inaccurate expectations made me feel like a failure doing something that was supposed to be fun, I needed to adjust the expectations!

Boy did I find a goldmine in her!!!

Jeremy
 
Well said Jeremy.....by your wife that is!

We had a visitor to our campsite one year at OSH and the subject of build times came up. This guy could not fathom how anyone could build an airplane without having a set time table and definite scheduled completion time. He was absolutely adamant about it..... and so WRONG!

To the original poster...Regarding the 6 vs 7, You really should be basing your decision on what airplane you feel will fulfill all your mission profiles as well as the most important aspect of all.... Which one will make you the happiest? When you get down to it, hopefully you will spend more time flying than you will building.

Which ever direction you head, you will have a blast building, or assembling either one. Once you get done, fly it up to NE Wisconsin so I can have a look. Us Cheeseheads need to stick together!

Best Regards
 
To the original poster...Regarding the 6 vs 7, You really should be basing your decision on what airplane you feel will fulfill all your mission profiles as well as the most important aspect of all.... Which one will make you the happiest? When you get down to it, hopefully you will spend more time flying than you will building.

I really think that the short "classic tailed" RV6(A) looks better. Especially how they sit tail low. Perhaps it's just a tad closer to that P-51 look.:) Therefor, it makes me the "happiest". And I know that other "classic tail" enthusiast agree, as it's been often said over the years! :D

L.Adamson
 
Thanks for all of the input! I have not flown in either of the models (only flown in an -8), but I'm not too worried about liking one model in the air more than the other. There are just too many positive reviews of Vans planes in general to worry about which plane will be better to fly. I just wanted to find out how the build process would differ between the planes. Sounds like the 7 is just a little further along in the evolution of kits. I think it will ultimately come down to circumstances - when I'm ready to pull the trigger, if a 6 kit is available at a discount I may go that route just to save a chunk of change. If not, I'll piece-meal it through the 7 kit. I love working with my hands and building, so I have no need to fast track anything. Can't wait!

Brandon
 
One thing I always liked about my six. There have been no inflight structural failures for a RV6. The same can’t be said about the 7.
 
Believe it or not....

With a two axis auto-pilot, and a blind-fold; you wouldn't be able to tell the difference between the 6 & 9 on a long cross country flight. And that includes turbulence. I've got a 6A, but a lot of 9A flight time; which is mostly cross country. A friend has built two 9A's, and has around 350 9A hours. We both agree on this point regarding the 6 versus the 9 for cross country. They simply don't feel different. I flew the 9A just a few days ago for conformation. :)

L.Adamson --- RV6A

Interesting observation, and seems to fly in the face of conventional VAF wisdom, which opines that the lower wing loading of the RV-9 and -9A reportedly makes for a seriously rough ride in any bumpy air. I haven't noted that myself and am inclined to discount it, but my experience with the RV-6/A is limited.
 
someone above mentioned more space in the 7. Given the canopy bubble is identical... I wonder where that additional space is. Both are 43" width at the shoulders. Both list 12+ cubic feet of baggage.

If you look at a quickbuild 6 vs quickbuild 7, the difference in fuselage build time (in my opinion having a QB6) is so little it will be lost in the noise. Meanwhile you'll probably pay half for the 6 kit. You should be able to find a good completed 6 tail section.

And the 6 is happy with a 320 engine. If you are trying to keep costs down I suspect you can pickup a 320 core or used for less $ than the 360. Why? Because everyone wants the 360... to put into their 7, or, 8, or 9...

As others mention... a boat load of time can go into wiring, firewall forward, avionics, etc. Early 6's suffer from a lack of documentation on 'where do I put that' firewall forward. BUT if you have a blank firewall 6 - you can use the 7 additional plans to do that layout. Been there, done that. Yes, you'll spend a little more time there. But if the kit is significantly less $, it's sweat equity.
 
someone above mentioned more space in the 7. Given the canopy bubble is identical... I wonder where that additional space is. Both are 43" width at the shoulders. Both list 12+ cubic feet of baggage.

We had a RV-7 QB kit arrive a few years back and at the time my RV-6 slo-build was at the same stage - ie: the upright Canoe stage. We measured the two fuselages to compare dimensions and we surprised to find the following:

Firewall to Aft Baggage wall distance - exactly the same.

Seat base to canopy - the RV-7 had an extra inch. This was accomplished by dropping the RV-7 seat pan by about 1" so that gap between the bottom fuselage skin and the seat pan skin is less than the RV-6.

Distance from the Firewall to the Seatback cross-member (F-604) was the same.

So there is very little difference between the two aircraft cabins.
 
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