Just wondering here. Relating to design, what are the specific performance differences between the Cox Medallion and Tee Dee .09 engines? 

The TeeDee is very different (factory) from the Medallion in three significant ways (four if you consider power)

1. TD crank front induction....very large square port vs Medallion much smaller round port (significantly limits free flo ((less power))but dramatically increases ability to draw fuel / air from a hard tank)

2. TD cylinder vs Medallion cylinders..The (factory) TD has 2 by pass x 2 boost ports ...Medallion 2 by pass x 0 boost ports

3. Glow plug heads...TD typically has a high(er) compression trumpet shaped head vs Medallion standard bowl shaped (no such thing as Low compression glow head)

Both front induction engines can achieve significantly higher RPM vs reed valve same displacement COX engines

In standard factory configuration the TeeDee is a pain to start with hard tank...but very reliable with a pressure fuel system...Also to get more power many FF or combat or racers would deliberately open the venturie...certifying the need for pressure fuel system...dooh!

Conversely a factory Medallion was deliberately configured to be very easy to start on hard tank by the weekend hobby pilot

Today with Matt and Bernie supplying a lot of original or costume parts (but zero .051 stuff) we can mix n match a lot of combinations

I have built from new old stock many TeeDee engines for light combat foam wings....not on par with (now unobtainable) $50ish Aero NV .049s....but very fun engines....that said, a full TD build is about same cost of a NIB Cox .049 around $109~$125

I still have a couple NIB  .049  TDs and a hand full of costume builds ready for new homes...pm for details

I've not found them hard to start either, but the venturis and needle assemblies on the several I've owned had a bad habit of coming loose ...


Dennis

Just wondering here. Relating to design, what are the specific performance differences between the Cox Medallion and Tee Dee .09 engines? 

Wayne's question was about the differences between the Cox Medallion and TD .09 engines.

What seems to be the response above is that all or at least most of the comments are about Cox Medallion and TD .049 engines.  I would also like to know the differences from those who have experience, physically and operationally, between the Cox .09 engines. 

Keith

I've always been a TeeDee man, with the exception of a couple Medallions got in a sell-off and didn't much like them.  Maybe the first owner abused them.  I'm never know.


True, the TeeDee venturi is a big large for suction, but I solved that by gluing it shut with JB, then redrilling it to usable size.  This was accomplished with the venturi unscrewed from the engine. This setup works fine for stunt and scale and the loss of power is minimal.

Another problem in 1/2A Combat was breaking the carb housing when checking the turf.  While carrying a good supply of spares was one approach, I came up with better root cause solution.

I put a Medallion carb body on the TeeDee and fashioned homemade dump tube, which was connected to rear remote NVA. 

True, the TeeDee venturi is a big large for suction, but I solved that by gluing it shut with JB, then redrilling it to usable size.  This was accomplished with the venturi unscrewed from the engine. This setup works fine for stunt and scale and the loss of power is minimal.

 Hey Paul, The post I deleted ( because Keith T. took exception to it ),
talked about all the TD / Medallion testing I did and I linked to
the video of it flying.
C'est la vie.

  I took your advice and sleeved the TD .049 down using J&B
aluminum tube. The TD runs very decently with the sleeved
venturi and sucks the tank dry every flight.
Thanks for your spot on help.

FWIW my .049 Medallions also run fine but aren't as easy to
start. I guess everyone's experiences come down to the
individual engines.
- K.

Hello Keith T,

   Hope I didn't offend you. It was my oversight
about the .09 topic. You were correct.
  My only excuse is that this is a 1/2A forum and
the issues being discussed were about TD's being
difficult to run as stunt engines.

Cheers! - K.