Thorp Air Command - T18.net

Stuart,
A couple of answers for you ...

Question: There seems to be a lot of rivets for the fuel door doubler plate. From the examples in my sheet metal books you could get away with about half that number of rivets. Are the extra rivets there because you wanted to strengthen the relatively thin .025 material around the door or for some other reason?

Answer: I treated the fuel door as I would any other inspection plate. I have a generic template that I use for such things, the rivet pattern comes from that. The rivet pattern is consistant with AC-43.

Question: I am curious about the assembly sequence for the firewall area shown in this picture.
Did you cleco the firewall to the frames bare and then attach the doublers, landing gear beam and fuel tank brackets to the firewall or did you complete riveting the fittings to the firewall and then attach the completed firewall to the rest of the airframe?

Answer: In this case I replaced the firewall. So basically everything with the exception of the firewall was still attached to the airframe. The cowl skin was off so installing the firewall was quite easy, I just clecoed the firewall in place and riveted it on. Then installed the cowl skin.

Hope that helps ...

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD

Thanks Lee
Re the fuel door. I was recently drawing up the cowling oil door based on a picture in Tony Bingelis Sport plane Construction Techniques book, and that has probably confused the issue for me, having a door in the cowling is not going to be the same as elsewhere in the aircraft structure!
I'm also no expert on AC43 so probably have mis understood the detail of it as well.
I have attached what I had been drawing and previously been thinking was adequate.

Any chance I could "borrow" your generic AC43 compliant template?

Regards
Stuart

You can use a concealed hinge like the RV guys use on their oil door and not have the exposed piano hinge. I used the concealed hinges on my cowl cheeks .

RB

Rich I was going to take a look at that, the hidden hinge option would be nice, initially i thought it was going to be more complicated to do but since looking at it a bit more i think it shouldn't be too hard.
Stuart

Homemade Hidden Hinge Photos.

I like the spring; wish I had made mine with one.

_________________
Bob Highley
N711SH
SN 835
KLAL

Seeing the pictures it looks pretty straight forward to fabricate the hinge, adding that little spring might take an extra bit of thinking. I think i can make that for less than the $40 they want for the hinges on one of the RV websites.

I wonder if you could install a long hinge pin bent at a 90 on both ends to make a Torque Spring?

or steal your kids hair clip, hopefully your daughters.

Bob MO

You guys have the right idea. The design of the hindge can not be to large as it will interfere with the fuel cap. I do believe that a hindge pin would be to stiff to flex. I found a spring from a plastic fuel line disconnect that Ford uses for their fuel lines for a $1.89 at Harbor frieght. Removed one hindge segment and installed spring.

Bought my concealed alum. hinges from Gruden.com for my cowel cheeks . Looks like the same hinge as Bill W. ? I think they were fairly cheap ? $3.00 each + shipping ?

Thanks for the pictures guys it`s always nice to see what your talking about and the work that is being done sure looks good.

Lance

The first hindge would be my choice, small and compact and will not interfere with thegas cap.

Correction on my hinge source. It is Guden.com

RB