Tee Dee questions

The only physical difference is that the bore on the .049 is 0.406 inches whereas the .051 is 0.410 inches. The .051 piston has a groove in the piston skirt for identification purposes.

The 051 has a red carb body and the 049 black, again for identification purposes but these are physically exactly the same size and are therefore interchangeable.

See http://en.wikipedia.org/wiki/Cox_model_engine for more information.

Cheers

What is the visual difference between TD's and Medallions?

microflitedude wrote:What is the visual difference between TD's and Medallions?

Bookmark this link: http://www.mh-aerotools.de/airfoils/cox_frameset.htm

It is one of the more definitive sites on COX engines and there are pictures of most of the models.

microflitedude wrote:What is the visual difference between TD's and Medallions?

The Medallion venturi is a molded plastic part of the carb body, and the spraybar is pressed through the venturi, not meant to be removable.
The TD venturi is aluminum and screws in securing the brass needle valve assembly to the carb body. The NVA can be removed for cleaning and repositioning on either side.
The crankcase is the same part on both. That's about it.

I would post pics if I had them, look on ebay listings for quick pics of the 2 diferent makes.

All of the Medallion engines ( as far as I am aware)had a throttle ring from the factory ; teedee`s did not.
Trying to keep the explanation rather simple:
medallion engines had a plastic venturi that the spray bar/needle valve inserted directly through whereas the teedee had a plastic carb body that several metal parts threaded into to complete the needle valve assembly; visually the two are recognizably diferent via the fuel induction pieces

Thanks guys.

Pics:


Medallion .049



TD .049

George

Jaspur_x wrote:I would post pics if I had them, look on ebay listings for quick pics of the 2 diferent makes.

All of the Medallion engines ( as far as I am aware)had a throttle ring from the factory ; teedee`s did not.

The Medallion 049 was a cheaper version of the TEE DEE dubbed as a Sport/Stunt Engine. Cox Cat #240 was the Sport/Stunt Engine (came out Nov 1961) They are significantly different internally to the Tee Dee. The Medallion used a 2 bypass straight cylinder with sub piston induction. (Later used on the Black Widow). It also had a different crankshaft to the Tee Dee.


Cox Cat #240-1 was the RC Version used an exhaust throttle ring and came out Nov 1969. (8 years later!)


There was also a later version Cat # 2501 that had a Muffler throttle that came out in 1988 and had the slit exhaust cylinder with no SPI.


The Tee Dee on the other hand was developed and sold as a Competition Engine. These never had a throttle ring or muffler, until the TD 05 came out in 1994.

The TD 049 was Cox Cat # 170 and came out in Nov 1960 (1 year before the Medallion) These had a competition crank with a huge intake orifice, and the cylinder was tapered, and had two bypass ports, with 2 bypass booster flutes on each port and used sub piston induction. It also employed a peripheral port venturi which could be enlarged if need be when running on pressure to obtain maximum performance.


The TD 051 was Cox Cat #200 and came out in Oct 1961 (1 year after the TD049). The only reason this engine came into existence was so that modelers could compete in 1/2A class and A class competitions using the same model but simply changing the engine. Porting and crankshaft was the same as the 049, the only differences being that the bore was .004 in (.1mm) bigger than the 049, the piston has a groove on the skirt and the carb body is red and is interchangeable with the black 049 carb body.


The Cox Cat #201 Tee Dee 05 RC was actually an 051 and came out Nov 1994. These have a special cylinder which has the same porting as the Tee Dee 051 but "no" SPI (Only 2000 were made)


Cheers

So then is it possible to run an .049 piston/cylinder on a .051 body?

JPvelo wrote:So then is it possible to run an .049 piston/cylinder on a .051 body?

YES it sure is and visa versa.

You can mix match alot of Medallion and Td parts together also and come up with different engines. Using Medallion bottom end with TD top end give nice UC stunt engine. The Medallion carb body wotks better than stock TD unit also for UC. I have not made hybrids but have seen them used and they worked quite well. Larry Renger who worked for Cox has done mucho experimenting on these. He helped develope KillerBee/ Venom/Viper while he was at Cox.