Thorp Air Command - T18.net

Hey all,
One of our members found a solution to our gas cap rubber problem. These inserts are professionally made. They pop right into your existing opening. They can be pro sealed in, or screwed in. The cap is an Aircraft Spruce PN. Cost me less than $30 and has a replaceable o ring.
I need to know what level of interest there is. More quantity equals lower pricing.
Cubes

This looks good to me.

I'd buy 3, one for each of my tanks.

I'll watch this thread for updates...

Thanks!

Peter

I should mention that the current design is 3.05” in diameter. There are several tank opening sizes. If yours is different, measure it and let me know. The machinist said he would flex.
Cubes

Mine are 3.05"

Cubes any ball park idea on total cost for cap and flange? I was planning on buying the Usher UD3 cap with the flat flange and cutting down the flange to 3.05" od and jb welding/prosealing/bolting it in. The RV guys aren't always happy with the Usher cap, I wonder if the Newton sprl cap you have pictured is a better cap?

Dave

I’m into it for $128 right now. The cap was $28. It is plastic. There is a company making them from aluminum, but they are $150-250 just for the cap. The insert is a prototype. I paid $100 to get this going. The machinist said the price would come down with quantity. I don’t know how much it will come down, or what quantity makes a difference. Right now, I have six signed up.
Cubes

I'm in for one too Cubes

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD

Wonder if the machinist could eliminate the 8 holes to cut down a little on machining time (and cost) for those that would want to only pro-seal mount them?

I can ask. I asked him to put those in there. I’d rather not just use pro seal.
Cubes

Cubes any idea if the flange that comes with the sprl cap would work as it is? Haven't found any dimensions anywhere to use to determine that. I would assume the od could be reduced to fit in the 3.06" diameter recess but not sure about the dimensions of the part that needs to stick down through the opening which is about 2.59" diameter on my tank.

Thanks for continuing to find a workable solution to our original gas cap dilemma.

Dave

I do not know. Sorry.
Cubes

From my experience, no, the flange that comes with the cap is an RV part so will not fit.

It looks like a nice setup if it doesn’t rely solely on squeezing rubber to secure the cap. I personally would not return to a thermos cap style. I don’t know that this setup would easily retrofit to my tank anyway. I believe my tank is an original plans built tank that was using the big Piper thermos style cap until it failed. I don’t recall the diameter but the filler neck is essentially a straight pipe sticking out of the tank so no flange available to set this one on let alone rivet it to even if the diameter worked.

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I spoke with the machinist today. We will not be ordering enough for a discount. So, it will be $100 a piece. You will have to buy the cap from Spruce. I’ll supply the part number if I can ever get a day off.
I asked if he would discount for not drilling the mounting holes and the answer was no.
Also, he said he was machining them slightly undersized on purpose to allow a place for the pro seal to go. I have some dimensions to get for him, but he has six identical to the one I have already on hand.
Let me do an experiment and drill some locating holes to make sure the one I have will work, then I’ll be sending out the parts to those who asked for them.
Cubes

Put me on the list for two also if it's not too late. I have failed in my attempts to make something work and I'm tired of prying my caps off every time I fuel. It'd be great to see pics of how you guys all mount yours when they arrive as well.

_________________
Marty G
N50LE
YouTube Channel
martygrosse@yahoo.com