TD vs. Medalion

Can anyone out there tell me the difference between a TD .049 and a Medalion .049 as seen on this link:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3154429962&category=34055

Which is better, more powerful, etc. Why?
Chris

How am I supposed to win a bid if you are telling everybody? LOL Yeah I was wondering the same thing. If it is better I would like to get one for the Envoy I plan on building.
Jay

Sorry Jay. Hope I don't mess you up.

>Can anyone out there tell me the difference between a TD
>.049 and a Medalion .049 as seen on this link:
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3154429962&category=34055
>
>Which is better, more powerful, etc. Why?
>Chris

TD (.049) has black nylon front housing, Medallion is red (the TD .051 is red also). Medallion has flat type prop washer while TD has pointy "spinner" type. Medallion has milder cylinder porting than TD does. Medallion can also be found in muffled and R/C throttle versions- that is about it.
"Better" is completely relative to the use to which you intend to put the motor.

>Medallion has milder cylinder porting than TD does. Medallion can >also be found in muffled and R/C throttle versions- that is about
>it.
>"Better" is completely relative to the use to which you
>intend to put the motor.
>
>J

Your right Jake, Better is not the right term. I actually was anticipating that response as I typed it. But, Power torque. . . That’s what I’m interested in. What does the Milder porting change?Chris

The TD also had a "true type" metal venturi while on the Medalion it was part of the front housing and the needle went through restrictor style. The TD, with its hotter porting and higher compression head was better for speed and free flight. Some used a milder sleeve on the TD when using them for stunt. Either could be used, however, since all you are doing is cranking them up to get as close to as much "oomph" as possible out of them for stunt.

Matt had a TD originally in his Baby Stuka. We later changed to a milder sleeve and from there went to a VA.

You can get steadier, more reliable runs from the Medallion, vs the Tee Dee. True, it is less powerful, but not by a lot. The Medallion is appropriate for models where a 1/2A is called for.

The differences are in the venturi type, crankshaft timing, cylinder porting, head, and cylinder/piston fit.

Tee Dee has the through type sprinkler venturi. Very efficient. The Medallion has a standard spraybar and needle.

Tee Dee has about twice the passage area on the crank timing, and much higher rpm tuning.

Tee Dee has extra bypass flutes cut into the cylinder.

Tee Dee uses the high-compression head, the Medallion uses the low, if I recall properly.

Tee Dee had (but no more, sadly) taper ground piston and cylinder. Medallion was always ground straight, exept for one batch we sneaked through for the NFFS guys.

Bottom line is that the Tee Dee would turn 3000 to 5000 more rpm than the Medallion. HOWEVER! The Medallion is a delightful stunt engine right out of the box, while the Tee Dee may require pressure feed to really go through the pattern reliably.

For some of the small kits like the Brodak Baby Flite Streak, the Medallion would be a perfect choice. A lightly built Pinto might even work well, though you probably could only use 40' lines instead of 45's.

You can run the Medallion with the high comp head, then play with gaskets to suit your needs. Currell

Larry: I am thinking that the rpm delta between the two motors is not as great as you post here, apples vs apples.

>Larry: I am thinking that the rpm delta between the two
>motors is not as great as you post here, apples vs apples.
>
>Currell
Hi Currell.....Yes It is... a well tuned(lapped,blueprinted)T.D.
will turn 24-24.5K on the ground with a Combat Prop....Mine did..
and I was using a stock I.D. venturi and Cox Racing fuel..They would
then unload approx 800-1200 rpm in the air. I think the comparison is differential...
I would personally choose the Medallion over the
T.D. for stunt; and I would choose the PAW .049 over the Medallion
as my final answer... . Tony( apples vs lemons vs oranges)

Tony: But let me lap and blueprint the Medallion too, for an honest comparison. Also, pick a compromise prop that doesn't give either motor a particular advantage. Currell

Forget not, my children, that I have seen the BOOK! In this case, the QC records of engine performance over the years of production at C*x before it's mighty fall.

My eyes have, perhaps, grown dim, my hair white, and my paunch not to be discussed, but still, I stand by the 3K to 5K difference even on the same fuel and prop!

It’s funny that the only one of these two motors you ever hear about is the TD. Up until this post I’ve never heard of a Medalion being recommended for anything, only the TD. It must have sold better due to the slightly higher output.? Does Cox still sell the Medalion?

LAST EDITED ON Nov-07-03 AT 03:49 PM (CST)
 
The last Medallion engines were a special batch run off for NFFS nostalgia events. They were slightly special, in fact, more special than we told the NFFS. They had the TD crankshaft and bypass porting and tapered cylinder/piston fit. A fit competitor to the Holland Hornet.

This would have been around 1998, I think.

Larry Renger
think S.M.A.L.L.

>Forget not, my children, that I have seen the BOOK! In this
>case, the QC records of engine performance over the years of
>production at C*x before it's mighty fall.
>
>My eyes have, perhaps, grown dim, my hair white, and my
>paunch not to be discussed>

Larry, before your memory goes as well, I wish you and anyone else that's still around that has "been there & done that" would sit down and detail as many of the Cox production processes as possible. When I look at the simple things, like glow plug washers, Tee Dee venturis (especially .010's) needle valves, etc., etc., not to mention pistons & cyl.s and try to imagine how to produce them CHEAPLY by the car load with the extreme accuracy that they were....my mind just goes bonkers! It would be extremely fascinating to hear how it was all done. I have all of the Dan Sitter articles in M.E.C. but there's not much detail about the machinery and processes involved. C'mon Mr. Wizard, tell us, please?

The basic machinery is known as "Screw Machines". They take bars of material and apply multiple operations to the bar as it is spun in the machine. After up to a dozen different cuts, the part is cut off and falls into a bucket for clean-up and whatever final processes were needed.

The other key processes were the centerless grinding for crankshafts and pistons, and honing for the cylinders. These were the operations that were kept in a carefully temperature controlled environment in the "good old days". This went away just after acquisition by Lakeside Industries around 1970.

There were a variety of multi-function, automated machines (usually called "Coxomatic") to do several after operations at once.

Guys like Bill Fogler, Charley Mackey and Dale Kirn know far more about those details than I.