Under fabric suprise

[Pilot78]

Group,
I tore the old fabric off my 1978 F-19 last night and found a few things I had not expected, just wondering if all the foam between the fabric and baggage area is "factory" or somebody's insulation idea? Also is the metal bracket on the bottom rear of the baggage area for a beacon or antenna, and there is a phenolic block with wires running to it in the forward part of the tail, is this also for an antenna or beacon? Any input is appreciated, Thanks.

Brian
SLC-UT

[Hank Jarrett]

Re: Under fabric suprise

The foam looks like upholstery foam. Have you tried to tear a little off and see if it burns? Most upholstery foam is flammable and isn't supposed to be in airplanes. It gives off toxic fumes. I SERIOUSLY doubt the factory would have even put aircraft foam under the fabric like that. It would hold moisture against the back of the fabric and lead to mold, rot and rusted tubes if water ever got in.
The plate with the wire looks like an antenna ground plane and the wood block also looks like a mount for an antenna or intercom or something. The wood block looks like it is home made, not factory.
Just guessing of course, but sometimes you can tell if something is original just from the way it is made.
Hank

[Pilot78]

Re: Under fabric suprise

Thanks for the input Hank, good point on flammability and moisture. Yes it is just cheap foam so it must have been somebody's great idea....needless to say it won't be going back in.

Brian

[Forrest Barber]

Re: Under fabric suprise

The plate is factory , the other is add-ons by someone... Hank is correct , get it out of there.

[Pilot78]

Re: Under fabric suprise

Forrest,
Do you have any documentation what the factory used that plate for?

Brian
SLC-UT

[Forrest Barber]

Re: Under fabric suprise

Check your paper work; it was antenna or beacon or what ever the customer wanted . Perhaps nothing on your ship. Do you original list of equipment?

[lawheelock]

Re: Under fabric suprise

Referencing the picture of the block in the tail fin.

The phenolic block in the tail fin is the mounting block for the "catwhisker" VOR antenna that was orignally factory installed.

I know, because I just recently dismantled an F-19 wreck that I bought for parts and the antenna and cables were all there and intact when I bought it.

I had also installed a "cat whisker" VOR antenna that used a similar mount block on my original BC12D (N96927) back in 1965 to use with the old Superhomer that I installed powered by battery and wind generator. I did not have shielded ignition and flying for hours and hours listening to that VOR signal to keep it tuned in with the organ grinder crank on the Superhomer is why my hearing got so damaged that the most powerful hearing aids don't help much today.

The antenna uses a doubled length of co-ax cable to create a balun, which is a transformer to match the balanced impedance of the dipole antenna "cat whisker" antenna to the unbalanced characteristics of RG-58 50 ohm coaxial cable to the VOR receiver.

Larry Wheelock, BC12D project N96179, A&P, IA, BS(Electronics Engineer), PE,also formerly held FAA Radio Repairman certificate (1970s)