Tee Dee carberator?

Yes I have here is one of my vids



Published on Mar 22, 2015

APC 4.75 x 4 / 19,380 rpm in the hand 25% nitro
21.4k to 23.3k rpm in the air dependent on direction.
Winds about 4 to 6 mph per hourly weather check. 74 F.

MauricioB wrote:

JPvelo wrote:Hello all,

Has anyone used one of these? Thoughts?

http://www.exmodelengines.com/cox-.049-.05-tee-dee-rc-carburetor-assembly.html

Thanks,

Jim

Hi Jim, I asked for help in the forum, and Mr. Balogh gave me good information, using the carburetor and the Throttle Ring together.
It works very well!.......

Nice video, Mauricio

Jim,
these R/C carbs originally came with the COX TD 050 R/C engines that also have a muffler on them... I believe not so much for noise baffling, but to retain heat in the cylinder during idle runs, when the normal COX heads tend to overcool and the idle would become erratic without heat retention.

Problem is that the TD 050 is a non-SPI engine that works well with mufflers, unlike the SPI engines e.g. the TD 049 and TD 051, that suck in exhaust gases from the muffler under the piston skirt when the SPI gap opens. So a muffler combined with an SPI engine normally entails some loss of power.

I thought that instead of the muffler, I use an exhaust throttle ring on a SPI engine like TD 051, that, when partly closed for idle, will also retain heat in the cylinder so the glow head remains hot, but the SPI engine will not suck in exhaust gases because the throttle ring will let them move away from the SPI gap area.

This is how I built the Double-Throttled TD (DTTD) that, even if SPI design, as Mauricio also experienced subsequently, will not lose power at full speed in lack of flue gas inhalation, and will also have a stable idle set by the R/C carb, enabled by the heat retention of the throttle ring. The exhaust throttle and the R/C carb operations are syncronized by a simple pushrod.



The engine of Brad (1/2 A Nut) does not use the throttle ring with the R/C carb, and I assume has a stable idle because of the Nelson or similar non-stock glow head on his engine that does not cool down in idle run, unlike the stock COX head that I use.