7AC rebuild and covering

[Hiperbiper]

Hi all (or y'all if you wish);
I'm in the fifth year of my one year project and thought I'd share...
I purchased this plane after the previous owner ran it off a strip, down an embankment and into the trees. (Gotta admire his determination...).
Originally I was only after the wings for a Breezy project but after stripping her down I decided to rebuild her. I welded in a new landing gear yoke, repaired the landing gear mounting lugs and repaired/replaced some fuselage tubing. The wings needed a few ribs on the right side and plus a through IRAN. I'm putting Grove brakes on as I'm not a fan of the Van Sickle mechanical setup. Other than the brakes and the two 5 gallon wing tanks she's stock...no big tail, no baggage door, no bomb racks...
I got as far as priming the fuselage in 2018 when a 1946 Navion project got in the way. Navion is now flying with a new owner so The Champ is next to fly!!!.
I'm putting the whole airplane together sans covering to insure I have every nut, bolt, screw and part required for completion, then I'll take her apart, label all the aforementioned pieces and get her covered and painted. Then I'll put it all together. This is my plan.

Remember Custer had a plan...

Chris in Shreveport

 

[Bartman]

Great to see another project thread Chris, really appreciate the effort it takes so thanks!

Is it me or is everyone secretly planning a Breezy build? What engine in the Champ?

Kudos to you for the welding and for taking on the repair/rebuild yourself. My four month project took two years, almost to the day so you'll get a lot of empathy here!

Keep up the good work!
Bart

 

[Bob Turner]

I think if I were a really talented welder I would convert to aluminum gear legs. Great idea going for the Grove kit. I think Robbie has my description. Trivially easy to install; you need to order your own flex hose and inverted flare fittings.

If you haven't already figured all that out, ask, and I will re-post my parts list.

 

[Hiperbiper]

Hi Bart,
The Champ came with a C85-12 someone installed with a Bic pen and little else.
SL 13 was referenced but no real work was done. I'm getting the STC from Bill Pancake to let me keep the small tail and up the gross weight to 1320#.
Luckily when it went off roading the prop didn't hit anything or so I was told. Just to be on the safe side I dialed the crank and then rebuilt the engine anyway as the logs were kinda sketchy...new slick mags and a Marvel Schebler carb were added to keep future problems to a minimum.
Breezy s are really fun to fly. Except for being so slow. And the bird strikes. And the bugs in the teeth. But still; really fun to fly!
Bob, thanks for the offer of help. I've used Grove wheels and master cylinders as well as their parking brake valve. Everything else is off the shelf aircraft stuff and Wag Aero repo parts. AN4 hardware and standard hoses and lines tie everything together...

I did get a call from Preferred Airparts today, they shipped my slip covers and all the Polyfiber stuff today. I just ordered it Wednesday! And because I got the fabric, paint and everything else at the same time they picked up the freight to my shop. YEA!!!
Chris

 

[Hiperbiper]

To answer the age old question:
The current cost of materials used to cover an Aeronca 7AC is $7400.00. **
This includes slip covers for the wings and fuselage, medium fabric for all the smaller stuff, all the reinforcing tapes, the 2,3 and 4 inch finishing tape, inter rib tape, anti chafe tape, metal drain grommets, plastic inspection rings (40), C-2210 fabric cleaner, Poly Tac, Poly Brush, Poly Spray and 11 gallons of Aerothane paint/catalyst (85* version).
It also includes 2 gallons of MEK (the real stuff). I ordered an extra 2 gallons but these aren't included in the above price...
Preferred Airparts in Ohio was a pleasure to work with (thanks Drew!).
As I already have plenty of 1, 2 and 3 inch brushes for the poly tac and poly brush all I need now is a bunch of short nap paint rollers in various sizes from Home Depot for the top coat...

Chris

** Update to the amount of material used for completing the airplane. I overbought my materials by around $1800.00-$2000.00. All my fault!
So using all Polyfiber goods, wing and fuselage envelopes and having some paint, etc. left over for repairs my actual material cost was less than $5000.00 to get the whole airplane covered.

 

[Bob Turner]

Been a while since I did an entire airplane, but I just finished one Cub wing. 15 yards of fabric, and enough left over for fuselage patches and gear legs. Two gallons each of poly brush, poly spray, poly white. One gallon of Airtech yellow, plus catalyst and thinner. We have a half gallon of that left over.

Multiply that by three for what it would take to do an entire airplane. Tapes and cord add another $200 or so.

You are going to roll the Aerothane?

I am rounding up to $1500 for a third of a Cub (to cover thinners and Poly Tak) so my guess is $4500. I have never done an envelope cover, so cannot speak to that cost.

 

[Hiperbiper]

Not really going to roll on the Aerothane...

Just seeing if anyone was paying attention

 

[BB57]

Not really going to roll on the Aerothane...

Just seeing if anyone was paying attention

Since I'd painted my own home built glider in the past, someone asked me if I could paint his Ercoupe. I said sure, I can paint anything - I have a brush and a roller. They laughed, I laughed, we all laughed. I'm pretty good with a HVLP spray gun, but I'm not real interested in painting someone else's airplane.

 

[Hiperbiper]

Well, she's all there and together. New elevator and rudder cables have been made up and rigged, new wing to fuselage fairings have been made, new windshield and windows trimmed and ready to mount. New throttle, mixture and carb heat cables run to they're respective levers, all three fuel tanks plumbed.

Now I'll take it apart, strip, prime, cover and paint...after I get my paint booth assembled in my other hangar . Shouldn't take more than a couple of weeks right?
I'll post updates should any actual progress occur.
Chris

 

[Hiperbiper]

As my project came with seat belts of questionable pedigree I ordered a complete set belts and harnesses for the Aeronca from Wag Aero. I had been planning to attach the shoulder harnesses with 1/8" cable in the back and around the rear spar carry thru for the front.
When I received the package I was surprised to find mounts for both front and rear harnesses complete with STC paperwork! The Wag Aero catalog didn't mention anything about any of this. I thought I was getting two plain jane belt/harness sets...so I removed the rear cable I had made up and filled the slots I'd cut in the greenhouse woodwork. With the exception of having the slightly elongate the two end holes to allow the bushings to fit the carry-thru the install was relatively painless. I'll have to pad around the brace to make the headliner look good...
This is the fun part of rebuilding airplanes, putting parts back on and having visible progress you can show...

Chris

 

[Hiperbiper]

The headliner and I finally came to an agreement...it decided to stay put and I decided not to douse it in gasoline and reduce it to ashes...
I've still got to cut a slit for the rear seat shoulder harness and make panels for the greenhouse sides but mostly I'm pleased with the results.
I'd just completed the headliner on the Navion and believe it or not I think it was easier. Larger but easier.
Chris

 

[aftCG]

The head liner looks great. I like looking at the pictures when these things are apart. That fuel tank, wow. That would make the instrument panel a whole different game compared to the Citabria.

 

[Bob Turner]

Thanks for the detailed shots of the shoulder harness mounts. I like the rear mount, although I would say the size of bolt was predicated on a more robust attach point than an airplane frame. They should run some shear computations on those AN-6 bolts.

 

[Hiperbiper]

Thanks.
Yea, the fuel tank limits what can go in the panel. At least it USED to...with the advent of the AV30 even a lowly 1946 puddle jumper can experience the joys of the digital age Artificial Horizon.
Or not...
There's still something to be said for paper sectionals and lookin' out the window.

Chris

 

[Hiperbiper]

Bob,
An AN6 bolt has a Tensile strength of not less than 125,000 psi. (direct axis pull).
Assuming shear strength is 60% of Tensile strength the bolt will maintain function at 75,000 psi. (direct 90* from long axis pull).
At the other end of that bolt is my collarbone(s)...
My instinct is by the time that bolt gives up Mrs. Carlson 's little boy will be beyond caring...

And no, I'm not looking to prove it!!!

Chris (Mr. Chicken)

 

[Bob Turner]

We found that an AN-3 would fail long after the tube it is attached to turned into steel spaghetti. Old Air Force lap straps were set up for AN-4, as is my Decathlon.

All AN bolts are 125,000 tensile. You have to find out how much of a square inch is involved.

 

[Hiperbiper]

We found that an AN-3 would fail long after the tube it is attached to turned into steel spaghetti. Old Air Force lap straps were set up for AN-4, as is my Decathlon.

All AN bolts are 125,000 tensile. You have to find out how much of a square inch is involved.

Yea but you Air Force guys also routinely had explosives and rocket motors hidden under your seats...

 

[Bob Turner]

No, these were the light green 3" seatbelts. Wish I could find more - they were used long before ejection seats - AT-6, recip bombers - really good seat belts.

I can easily do the computations for you - I think the shoulder harness shear failure point, using one AN-3, was 1900 lbs, so if you think an upper torso is 100 lbs that is 19 Gs. The collapse of the airframe will lessen the instantaneous G force to less than that.

 

[Hiperbiper]

I decided to go ahead and build new interior panels for the Champ.I was doing some sheet metal work on an RV8 and had all my tools out and aluminum shavings everywhere and got tired of looking at the ratty old interior parts sitting in the hangar.
The new panels fit better and are designed with some stiffeners on the long panels which will help 'em last longer...
The whole aft wall comes off easily to allow access to the rear of the plane (a friend with a 7ec had a handheld migrate to the tail and getting it out convinced me a larger portal is desirable). I also found a good place for my Microaire radio and the intercom.
Next up; Alodine and paint...

That pic of the heater is a tribute to my wife. She came to look at the plane and noticed the hangar was a crisp 40*...next day a Lowe's truck pulled up and dropped off the 135,000 btu heater...that sucker will take the hangar from 30 to 60 degrees in an hour!!!
I must say I married rather well...
Pity she didn't...


Chris (now working in t-shirts again)

 

[Goodyear]

That is very nice. What thickness aluminum did you use? Where does the battery go in a Champ?