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Author Topic: TD .09  (Read 1000 times)

Offline bob werle

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TD .09
« on: December 04, 2012, 11:11:40 AM »
I have 2 never run TD .09's  I would like th detune them somewhat to run on suction and 10% nitro for stunt.  I was going to use a glow plug adapter head in place on the std Cox glow plug.  I was thinking this would tame the TD a bit.  Is there anything eld I should be thinking of?
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Offline Andrew Tinsley

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Re: TD .09
« Reply #1 on: December 04, 2012, 11:23:11 AM »
A few more head shims to decompress further and a reduction in choke area would maybe help. I would be tempted to swop it for a Medallion 0.9. Not as powerful but a lot more stunt friendly in my experience.

Regards,

Andrew.
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Offline Jim Thomerson

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Re: TD .09
« Reply #2 on: December 04, 2012, 06:37:07 PM »
I've flown TD 09s on Sig Champion 10% nitro, 20% oil, half and half, for some years on 15 size airplanes in OTS and Classic.  Best prop is Cox 7 x 3.5.  I flew them on 55 to 57 ft, eyelet to eyelet 012 lines, depending on the airplane.  I used backplate pressure with a one way valve in the line, uniflow tank.  The stock NVA works fine.  Release at 14,500 to 15,000 RPM.  I never tried detuning them, but I imagine a Medallion head or an adaptor for regular plug would work.
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Offline Andrew Tinsley

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Re: TD .09
« Reply #3 on: December 05, 2012, 03:24:57 PM »
Hello Jim,
I have never had a lot of joy trying to run TDs on backplate pressure (I assume that is crank case pressure in English English!). Are there any tips you could pass on? I think maybe my pressure tap was too big?

Thanks,

Andrew.
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Offline dennis lipsett

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Re: TD .09
« Reply #4 on: December 06, 2012, 12:14:30 PM »
Andrew,

I flew a lot of The TD 09's and of course the 049/051 also. always made my own pressure tap and JB welded it or epoxied it into the backplate. Make it out of 1/32 tubing, take a pin and blacken it with the flame from a match. stick it in and solder the tube shut. Quickly pull out the pin before the solder has solidified. You should have a 6 thou hole there. It will work perfectly. Biggest problem with pressure taps it that most of them are too big.

While your at it make sure that you bend the tube so that it is pointing up towards the cylinder.It makes life much simpler removing  or servicing the tubing I usually wrap a few winds of copper around the copper tube tip and rub a little JB weld over it to give some grip to the tubing

Dennis
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Offline bob werle

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Re: TD .09
« Reply #5 on: December 06, 2012, 12:50:34 PM »
Thank you for all your information.  I will set up a test run on suction and using the head adapter and let you know what the results are.  I have had these 2 motors for quite a while and just want tro see them in the air.
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Offline kenneth cook

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Re: TD .09
« Reply #6 on: December 06, 2012, 02:24:37 PM »
        I would think that choking down the venturi area is the best bet. Probably adding the .09 Medallion carb body would be simple enough. Keeping a narrow tank as well. Having a wedge with the pickup way outboard is certainly going to be problematic. Roy Clough published the "Stunt Goat" in Flying Models in 99 which featured a profile stunter with the TD.09. He inserted the wedge by cutting out material between the beams and inserted the wedge from the inboard side of the fuselage. The pickup was only about 3/8"-1/2" protruding through the outboard doubler. This places the pickup inline with the TD fuel nipple which minimizes problems with fuel draw. Ken
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Offline dennis lipsett

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Re: TD .09
« Reply #7 on: December 06, 2012, 07:19:12 PM »
Quote from: kenneth cook on December 06, 2012, 02:24:37 PM
       I would think that choking down the venturi area is the best bet. Probably adding the .09 Medallion carb body would be simple enough. Keeping a narrow tank as well. Having a wedge with the pickup way outboard is certainly going to be problematic. Roy Clough published the "Stunt Goat" in Flying Models in 99 which featured a profile stunter with the TD.09. He inserted the wedge by cutting out material between the beams and inserted the wedge from the inboard side of the fuselage. The pickup was only about 3/8"-1/2" protruding through the outboard doubler. This places the pickup inline with the TD fuel nipple which minimizes problems with fuel draw. Ken

Ken,
Putting a Medallion carb front end on is not going to do too much to slow the engine down. I never had too much success playing with venturi sizes. But as you know the TD09 is sensitive to what prop it likes. Give it the wrong one and you can turn it into a real doggy stunt engine if your so inclined. Besides it's cheaper then buying parts for an out of production engine
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Offline Andrew Tinsley

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Re: TD .09
« Reply #8 on: December 07, 2012, 03:18:50 AM »
Hello Dennis,
Thanks for the tip on getting a small enough diameter pressure tap. As I suspected, mine was too large. Next time I try a TD, I will give your technique a go. Knowing my luck I will probably solder the pin in permanently.
 Going more off topic, what is the rationale for using such a small hole? Or should I say the reason, the rationale is that it works!

Andrew.
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Offline Trostle

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Re: TD .09
« Reply #9 on: December 07, 2012, 09:06:36 AM »
Quote from: Andrew Tinsley on December 07, 2012, 03:18:50 AM
Hello Dennis,
Thanks for the tip on getting a small enough diameter pressure tap. As I suspected, mine was too large. Next time I try a TD, I will give your technique a go. Knowing my luck I will probably solder the pin in permanently.
 Going more off topic, what is the rationale for using such a small hole? Or should I say the reason, the rationale is that it works!

Andrew.

The process of holding a piece of wire over a burning match or candle to coat it with soot works.  Just put the coated wire in the 1/32" id brass tubing, fill the tube with solder, then pull out the wire.  This leaves a very nice SMALL hole, the diameter of the wire.  The idea of using a small hole is to reduce the pressure from the crankcase that you are sending to the fuel system.  Full crankcase pressure to the fuel system is a lot more than necessary and makes it difficult to set the needle and get a consistent run which is the reason for a pressurized fuel system.

KT
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