7 vs 7a Quick Build question

[CPSONE]

At what point does a builder have to decide between the 7 and 7A when ordering the QB version?
I see there is $770 price difference in the 7 and 7A on the Van's order form.
I'm looking to possibly purchase a "used" 7QB that's pretty well not started but concerned about what else I would have to buy to make it a 7A.

 

[DanBaier]

Check your emp plans

I think there are some differences in the construction of the vertical stabilizer.

Dan

 

[jmjula]

I am no quick build expert (slow build for me), but you will need to buy the 7A gear weldments and legs(?), likely new cabin covers to mate with those, and replace a bracket on the firewall for the brake line fittings. Those are the additional items that come to mind. The gear changes will be the high price items.

 

[CPSONE]

VS rivets for 7A

I think there are some differences in the construction of the vertical stabilizer.

Dan

Looked at the plans and yes the bottom hinge bracket VS410PP has different rivet holes for the 7 VS 7A. After looking at my VS that is completed I noticed I forgot to put in those two bottom corner rivet holes and it's now all riveted together. DWG 27A shows 426AD4-7's in this location, flush head forward. Any way I can get these in there without taking the whole darn thing appart? Rear spar is too thin to machine countershink for 4- rivets.

 

[ao.frog]

A thought...

If you ever want to put that sissy wheel up front back to where it belongs .. ....you need the tailwheel bracket.

Since this is a -7, the TW bracket is either riveted in place or is lying among the other parts.

This TW bracket is enclosed by ALOT of rivets in the aft tailsection, so it's alot of work to drill them all out to be able to install the TW bracket later on.
It might damage the tailsection a little too, depending of your drilling skills.
Take a look at the plans and you'll see what I mean.

If you install the TW-bracket, it'll be much easier to make the A into a taildragger later on, if you ever want to do that.
Ofcourse there's alot of other things to change: the gearlegs, the engine-mount etc etc, but the TW-bracket is the only thing which is enclosed in the fuse.

And if you are sure you won't ever go that route, then maybe the next owner will?

Doing it this way will solve the problem with the two mentioned rivets too....

Vans has done this change with their -7, (they did it the other way around I think: -7 into a 7A). Maybe you could send them an e-mail to get their opunion?

My 2 cents....

 

[Sig600]

Talk to Greg A on here. He recently converted his 9a to a 9.

I can't imagine trying to put the tailwheel bracket in on a completed/painted airplane. I was ready to jam a screw driver in my eye installing mine.

 

[CPSONE]

7 to 7a parts kit

Word from Van's...
Here's the parts list from Van's to change a 7 to a 7A as they did
with N137RV.

You would need to following Fuselage Kit to turn a -7 into a -7A:


7A FUSE UNIQUE UNIQUE PARTS SUB-17A $1560.00
1.000 F-6122-1 TRI-GEAR BRAKE BRAKET
1.000 F-982A-L COVER PLATE
1.000 F-982A-R COVER PLATE
1.000 AEX TIE DOWN X7.5 TIE DOWN X 7 1/2"
2.000 U-403-PC BRAKE MOUNT FLANGE
2.000 VA-106 MAIN GEAR AXLE NUT
1.000 F-877A-1 BATTERY TRAY
1.000 AS3-125X1X3 EF-605 (INCHES)
0.000 NOT IN SUB 17A LOOSEPARTS 7A/9A ONLY
1.000 U-701A-L-PC 7A MAIN GEAR LEG *
1.000 U-701A-R-PC 7A MAIN GEAR LEG *
1.000 WD-721-L-PC 7A LANDING GEAR MNT.*
1.000 WD-721-R-PC 7A LANDING GEAR MNT.*

 

[sahrens]

A conversion the other way

I went from 7A to 7 on my slow build, so I think I can answer your question. The VS hinge part has been mentioned. I was at the point of riveting the F-770 skins on my fuselage when my heart won the arguement and I decided to change my 7A SB to a 7 much slower build.

I spoke with Vans support (they were very helpful) and they identified the parts list I needed. That was the easy part. There was some de-construction needed. For example I replaced the F-712 bulkhead, it had the tie down riveted to it and I need to get the TW spring mount in place.

Fortunately I did not wait any longer, with the fuselage F-770 skins off I could still move about the fuselage easily. It was not a rigid component. What has taken the most time is going back through the build and making sure I did not miss anything else that was unique to a 7 vs a 7A.

On a QB two items that will be a little challenging for your conversion is cutting the opening for the gear legs. That skin will be riveted in place, I had already prefitted the gear weldment and made those openings. The other will be the addition of steps, if you want them. I think 7QBs do not come with steps unless they are specifically ordered that way. Drilling those holes into the baggage compartment will be a unique challenge. These are not impossible, they will just take a little more head scratching.

At the end of the day it is your build, time and money. If you are getting a great deal on a "used" 7QB that is one way to go. If you are trying to justify the $700 difference in the 7 vs the 7A, what is the value of your time? I know I have used up a lot of time converting mine.

Whatever you decision, good luck and build the plane YOU want.

 

[CPSONE]

7A QB

Thanks to all for the input.
Bought a QB7A slider project with the finish kit last weekend so no conversion required. Excellent!