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RV7 with 9 wings? possible?

N59ST

I'm New Here
I am preparing to start an RV7, It meets our mission perfectly.

With the thought of Experimental Aviation in mind, I wonder since the 9 shares fuselage and empennage, would it be possible to build a set of 9 wings and "swap" wings out for higher altitude X-country trips? I have not put the costs to the calculator, I would imagine the cost of the wing kits (if Vans would even sell them to a 7 owner) would take a long time to recoup compared to the cruise economy improvement. There is the obvious change in wing aspect ratio, slight increase in SqFt., and smaller tanks. Thinking there maybe CG issues also with the wing chord change and the heavier AIO-360 that is planned.

It is just a thought, it is not like swapping wings and re-rigging would be a 30 minute job. Is just more of a theoretical question. The 7 has enough wing and speed, ceiling is very close to a 9 already.
 
The first time you attempt to install the close tolerance wing bolts will cure you of any thoughts of ever removing them! :)

Also, the 9 and the 7 have very similar fuselages, but they are not identical.
 
No, you can't install 9 wings on a 7, or vice-versa.

One option might be swappable wing tips on a 7. Properly engineered, they could provide cruise benefits on long flights yet be swapped out for standard tips for local/fun flying. You'd take a g-limit hit with thw cruise tips in place.

But that's a lot of trouble for smallish gains, unless you rwallylike doing that sort of thing and can do it properly. I've thought about at least designing some (or a set of tapered wings) as an educational exercise but I'm an AE by schooling and profession.
 
Isn't the carry through different on the 9 as well?

Also, as I recall the H-Stab on the RV-9 is perpendicular to the wing and larger than the RV-7, whereas the RV-7 is smaller and tapered toward the outboard tips a bit.
 
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The empinage is not the same. The HS and elevators are larger on the -9. I was told by "Van's" that on the prototype, which was a -6 with -9 wings, that the slotted flaps blanketed the HS and elevators, which is why the -9 has that big slab of an HS.

The VS and rudder are the same.

As for the wings, fuel tank support brackets are different and may be in a different location and the forward side skins are different. I don't know if the rest spar is in the same location on the -7 & -9. I do know they share the same dihedral but don't know about the bolt pattern.
 
Only took me a couple days to get all the wing bolts in, and I magically learned French in teh process. Even if they did fit, I dread ever having to remove or install those bolts again in my lifetime. Let alone do it on a regular basis.

Love my 9, but I don't think the 7 or 9 are different enough that you need "both". If you plan to go upside down go 7 and be done. If no upside down needed the 9 is awesome.
 
Others

As others have me tion the 9 and 7 share common parts but are not the same pick your poison, the 7 or the 9. If you cant decide , then pick the 14
 
Every theoretical wing swap evolution would probably trigger another phase 1 type of event.
 
The empinage is not the same. The HS and elevators are larger on the -9. I was told by "Van's" that on the prototype, which was a -6 with -9 wings, that the slotted flaps blanketed the HS and elevators, which is why the -9 has that big slab of an HS.

Nope

Research center of lift change and pitching moment induced by flap deployment.
 
The other thing is, an 9 drivers may not like this, I fly my 7 with 200 hp engine and CS prop with a friend in his 9 with FP prop. At the same speed we get the same fuel consumption.

The 9 has its advantages of course, but rumours should be taken with a pinch of salt. If something sounds too good to be true there is often a simple explanation.
 
When the original post begins with the statement: "With the thought of Experimental Aviation in mind".... you just know you're in for some entertainment. Sometimes I just like the comedy on VansAirforce. :)
 
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Built and flew both 9 and 7. Fuselages are the same except in wing attach area with different ribs and spar box so you can not share wings. Plus the different horizonal stabilizer. Pick you mission and then plane. 9 is more stable feeling at altitude and is better for short/grass fields from my experience. 7 for aerobatics, higher speed and sportier flying. With 1000 hours in 9s and 12s, both could be floaters so I usually pulled all power for landing. I have finally learned that the 7 wants a little power on approach, then reduce in flare and add a little right before touch down for a smooth landing with nose gear up. For me that is taking more runway then I needed for the 9 or the 12.
 
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