Back in the Game

[PropMan]

I decided the prop needed to be finished while the woodshop is still reasonably cool, 79 degrees. (-:

[Cguy]

The dorsal fin area on any plane has always given me cold sweats, real visible too! But they have always come out OK just pretty challenging compared to most other areas.

[PropMan]

Looking like 2 days of work to attach each side. Half way done with the right side.

[PropMan]

Fabric has begun!!!
Belly is on, dang that took better part of today.

[Cguy]

Wow, flush rivets and fasteners, nice touch!

[PropMan]

Ok, got it done except for attachment and camloc fasteners, After seeing how much Camlocs are I elected to hinge it. Now we'll call it a door

[PropMan]

Brooks, Thanks for the pic. Yes, I plan on Stewarts method, then add the fasteners.

[Cguy]

One of the mods I did on both of my S-7 builds, was a aft baggage door, no regrets. It allows me to get into the area behind the baggage area, where I can keep light gear like a mattress pad, pillow, anything light but bulky. I also put a "ski hatch" in the plywood bulkhead at the rear of my baggage compartment, good for carrying 10' long PVC conduit, or a 78" Prince prop, both which I've done. Good advice on the fabric tension pulling things out of whack, as usual any mods lead to extra work!

[Bcone1381]

I recently installed my tail inspection frames and covers. Your cargo opening looks similar in design. Your material is exactly what I used for the frame and cover. Follow Stewarts Systems advice and attach your frame to your fabric from the inside after the first shrink to 250. After the glue cured an X is cut and fabric pushed through the frame, wrapped around and glued from the inside. The frame gets encapsulated.

If you choose to install quarter turn fastener receptacle after you cover & wrap, you eliminate obstructions from allowing fabric to adhere solid without those obstructions. After this photo was taken I riveted (squeezed) 4 tinnerman nut plates in each corner of the lower frame. It worked out nicely.

I also applied a zinc chromate coating to these frames. The AL gets roughed for a Stewarts Glue mechanical bond. I wonder if the AL might corrode over time and loose glue adhesion. So I roughen it, clean it, Chromate it, then glue it.

Screen Shot 2022-02-21 at 1.45.04 PM.png

[PropMan]

Thanks for the heads up, I've already riveted the frames on. So will look at it and come up with some sort of attachments without welding.

[BTAZ]

One suggestion.

When I shrank my fabric, it wanted to "roll" the bottom of the window frame out. I needed to reinforce it so(since the fabric was on I wasn't going to weld) used an Adel clamp on the diagonal tube that is roughly at the center of the window frame tied to a small aluminum bracket connected into the stringer that runs under the window frame.

I would suggest welding another "stringer standoff" to the diagonal tube at roughly the center of the window frame to better support the stringer against the tension of the fabric.

[PropMan]

The Hatch opening mostly done. Need to deburr and rivet. .025 was used for the outer ring and .020 to form the angle pieces. Two tabs were welded for lower attach point, aft attach is an existing tab for rear baggage closure and upper is simply drilled to stringer.
I'll weigh it before installing permanent just so I know what it cost me, other than a day of work an a few scraps of metal.
My initial thought is to use Dzus fasteners for the cover. Any other ideas are welcome.

[PropMan]

Well, here's a point where I add some weight, been debating this with myself for a while. Gonna install a small cargo "hatch" for two reasons. 1. Make servicing ELT and controls that are behind the cargo area easier 2. Loading things behind the rear seat will be easier also.
I call it a hatch because not putting hinges, using quarter turn fasteners. Seems the lightest and clean aerodynamically. But still quick to open

[Cguy]

Any time spent with a hole saw or a Uni-bit, is quality time! It pays off in satisfaction years down the road, every time you look at a part you spent a few more minutes on lightening, it has for me anyway. I have holes in my S-7S where no one else has, my thinking is the kit company stamps the part out, and they are done. That doesn't mean you can't put holes in it! The fun part is being smart about it of course. Also, when your plane comes out heavier than you wanted, (a given...) it helps a lot to know you did all you can to keep it light as possible.

[Craig Van Sickle]

Great details as usual. Thanks for the picts.