Re: Fuel supply for my TD, questions and answers

**RknRusty** Tue Nov 29, 2011 6:31 pm

Mark Boesen wrote:Bob you're a genius!

I saw you post and thought hmm...grabbed a couple needles and look for yourself. I don't see why they won't work.

A lot of older 1/2a's have 128TPI needles: Wen-Macs, Cubs, Andersons, Atwood/Holland but different tapers, but these look very close.

It fits mine perfectly. The one that I bent looks like it has a friendlier taper. The one from the postage stamp is slightly more stepped near the tip. I haven't cranked it up yet. I'm going to take it apart and clean it first since it ate dirt the other day. Lucky for me there is a screen on the venturi but it's too dirty to treat like a Bee. If you know what I mean. In other words I treat them like battle axes. A good blast of alcohol or fuel to knock off the dirt and send it off again. If it makes anybody feel better I do clean them off when I get home.

Mark Boesen Tue Nov 29, 2011 7:10 pm

The needle on the top of photo is from the postage stamp engine, I'm guessing there was a little variation with those too.

Kim Tue Nov 29, 2011 8:33 pm

Well Hoot ! Back to look'n in the junk box !!!!

Great call Bob !

dckrsn Tue Nov 29, 2011 10:20 pm

**RknRusty** Fri Dec 02, 2011 6:08 pm

I'm semi cross posting from my thread at RCG. But here's an update on my bumbling fuel system learning curve:
My TT needles and bladder kit was in the mail at 10 AM Thursday morning. I combined the TT instructions with the Clstunt tutorials and I love it. I had no idea you only needed an inch of surgical tube to make a bladder. My first one was bigger, but perfect for the Stuntman, and will hold nearly 2 ounces. I put a check valve and a Luer-Lock syringe adapter on its ass end so I can screw the syringe on and off without clamping while I fill it. And I got a bunch of Luer-Lock caps they always throw out at the dialysis clinic, so I can cap it off and keep it clean after filling. The check valve makes it really easy

I bought some Tee fittings. I would like to put one between the tank and the engine end of the bladder to make it easy to evacuate the air prior to filling. But the Tee has such small inside diameter I don't want to restrict fuel flow. But I expect it won't matter and the engine will just ask for a little more needle.

I mounted the new bladder on the Stuntman and put 40cc in it and the plane balances perfectly. No difference full or empty so it should fly fine this weekend. I put a wider venturi and a 5x3 prop on it and cranked it with 20cc. It ran for about 2:30 or so. That's how long a Black Widow runs on 8cc! I'll be needing more fuel soon. It's super easy to crank, easier than with vacuum feed. I just spun it giving the needle little tweaks from zero and when it started, I quickly spun it open until it kept running. I got it on about the third or fourth spin. The needle runs good at one place, it's really sensitive. That's the fastest I ever heard one run other than on youtube. It never wavered and would have flown straight up if I had let go. When I fly it, I guess I'll set it right on the edge of where it rolls off rich. One thing; I held the plane by the fuse behind the wing and the exhaust oil on my hand was gray. That bothered me, but all of the oil on the plane was clear pinkish, no gray on the plane except near the tail. I hope that sounds normal

I can't wait to give it another flight. I'll prop it down to a 6x3 for the next test flight and get it on video. I promised y'all a multi plane exhibition this weekend. Right now it's the Stuntman, the Li'l Satan and probably the Li'l Jumpin Bean. One of these days I'm going to put my semi-Killer Bee in the PT-19 and fly that.
I don't think I'll be slamming the ground this time since the Stuntman is balanced with and without fuel.
I need to make a spare bladder. I have enough fittings for one more. I should have bought a few extra fittings, they're all cheap except the $5 check valve. And it looks like I'll be needing more fuel soon too.

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