Medallion .09 Throttled clean up

Nice work Eric! Looks like new, are you going to sell it?

Great job!!!

These throttles came in a blister pack, I guess there where some mounting descriptions on the back but I don't think I have kept any of that. Would have to go through my old stuff...

Here is a picture of one I converted, it is straightforward to do;

I gone through a few boxes of cox stuff but it seems I didn't save the cards from the blister pack. There isn't much to it, but there is one "tuning" ability that one might not think of without the written description. The fuel delivery at the low end is actually adjustable, it is done by placing washers behind the plate in the front that links the carb throttle to the exhaust throttle. Putting washers here allows one to advance the carb restriction relative to the exhaust restriction. I haven't really played with it much but it is an interesting" tuning" option.

Here are my two mounted sets, one on a .049 and the other on a .09;

Thanks for the comments guys and to Kris for looking for the insert card for me , i noticed when i had this one apart that there was one washer behind the front lever . Nice looking engines i have a .049 also that's not been cleaned and i think is missing the rear lever for the servo hook up . I would like to run one of them but its a little cold and don't want to have to go through cleaning it again

Beautiful job on the .09, Eric.
I was thinking how cool it would be, if someone
would machine the Medallion carb bodies from
aluminum. Might be a bit of a feat though.
I have one of the aluminum ones on my TD .09.
Bob

dckrsn wrote:Beautiful job on the .09, Eric.
I was thinking how cool it would be, if someone
would machine the Medallion carb bodies from
aluminum. Might be a bit of a feat though.
I have one of the aluminum ones on my TD .09.
Bob

It would probably be much easier to make a Medallion style venturi to screw into the aluminum carb body. Then the user could choose between a Tee Dee or Medallion style set up.

Rather than create a new thread, thought it better to piggy back on Eric's thread, since it is related. Acquired this from E-Bay this week, now awaiting shipment home, a later muffled throttle ringed Medallion .09 RC. I'm stoked.  







BTW Eric, nice clean up job, have you tested your 1960's Medallion .09 RC? Curious minds want to know.

Nice looking engine George , i am sure you got plans for it ? / i just got a .049 with the slide throttle set up on it haven't had time to clean it yet ,, i think i am going to run it just to see how good it works .

Eric, got a 1959 Berkeley 46" (1170mm) span Impulse kit with airframe 90% assembled, but sat on back burner 2 years for lack of proper engine fitment for its narrow nose cheek cowl. Original Fox .09 Rocket lacked beam mounts and was bulkhead mounted, which would work, but I don't have that engine.

Engine .10 beam mounts are too wide to allow angling with proper shimming for side thrust. 1966 Enya .09-III TV, a preferred engine, 1965 OS Max 10R/C another preferred and A.C. Gilbert .11 Thunderhead beam mounts are too wide once mount is added to allow adjustment. At 4,300 ft (1311m) elevation, Cox .074 and Thunder Tiger .07 would provide marginal power, so they are out.

The Medallion .09 mount is narrower and will fit. Here is a glimpse of framing thus far, but not a total picture as I have progressed further.

Thumbs up Eric, great job on the Medallion cleanup. Some difference and colorful too.

Bob

Thanks Bob , I am glad after looking this long you have found an engine that will serve for the Impulse George . The plane is looking good also and should make a nice flyer with the single channel and wing atop . I remember this airplane from some time back you were looking for the correct engine .

Thanks, Eric. Impulse will be 3 channel, REM. Was originally thinking of splitting the wing trailing edge and making strip ailerons, but now will keep it simple and it will be a rudder plane.

Engine came in today and it is a real beaut, NOS never run, no bolt marks on the beam lugs, unweathered bright red plastic, solid compression, etc. I've never had this type throttle sleeve muffler before. The spring clip surrounding, which allows one to adjust the amount of noise versus back pressure is new to me. I guess one adjusts for the amount of noise and reliable idle one wants as there is no exhaust venting holes anywhere. My .049 RC Bee had a silicon cover over the exhaust restricter sleeve, which burbled open around its lower and looser circumference providing muffling.

In this 1959 Berkeley Impulse, with a Cox .09 engine mount there is sufficient clearance with the side cheek cowls to allow installing shimming washers to provide the proper amount of right thrust yet keep prop hub centered. I got it for $50 shipping included.

I'm stoked.

The fit looks perfect , man i bet you are stoked , thats a nice engine !! Heck , keep use in on the rest of the build and flight report too !!

Thanks, Eric, will do. BTW, another one has become available on E-Bay with 6 days left to bid, no bids, starting at $40 US.

ebay.com/Cox Medallion 09 Engine w-Throttle Muffler #112356816566




On your earlier 1960's Medallion .09 RC, Peter Chinn mentioned it had SPI, mentioning because of that would reduce power somewhat due to the wrap around nature of the exhaust restrictor setup. Does your have SPI? I checked mine through the exhaust restrictor ports and sure enough, it has SPI, too.

I also noticed that Bernie at Cox International has desirable parts for it, glow heads, needle valves, engine mounts and prized aluminum spinners.

Sorry George , I don't know if it had SPI or not and have sold the engine some time back But i just checked and the .09 Medallion w/throttle ring has a small amount of SPI

getback wrote:Sorry George , I don't know if it had SPI or not and have sold the engine some time back But i just checked and the .09 Medallion w/throttle ring has a small amount of SPI

Fact you sold it, Eric and being a rarer earlier Medallion, told me that you must have done well on the sale.

That is interesting, would be a less of a concern on a non-muffled throttle ring as SPI still would be functional at full throttle.

I don't know if ever came out with a non-SPI piston/sleeve combination for the Medallion and Tee Dee .09's. If they did, seems any NOS piston/sleeve sets are as rare as hen's teeth. Since the Medallion was their "sport" and not their "high performance" engine, I imagine that felt that a very small amount of exhaust gas recirculation from SPI was not enough to warrant a replacement.

May be they did have a non-SpI with additional bypass port set with the latest Tee Dee .09 R/C engine with true R/C carb prior to Cox selling out to Estes.

Nonetheless, this sport engine will suit me fine.

I bought a Mecoa .09 glow head adapter for my Medallion, came in the other day, bought it from a non-Mecoa E-Bay seller who offered at a cost I couldn't refuse.  Below, I have them temporarily seated on two sockets. The Cox head is hemispherical. The Mecoa is trumpet bell shaped, not much different than some performance heads. I haven't done volumetric comparisons yet like pour water or solvent and measure in a cup, but appears to have about the same volume as the Cox. Just doing flip tests, it seems to have comparable compression.



With similar volume, the Mecoa head may work out okay as this is a larger displacement engine than the smaller .049 ones.

There was someone who published their results in one of the other forums. He took a .049 glow plug adapter head and by carefully shaving away the seat until he had the same volume including the plug element cavity as the Cox head, obtained similar RPM's. Of course this is unnecessary as now there are adapter heads with a decent special insert that accomplish the same purpose.

I'll find out later when I run the engine. An interesting thing about the Mecoa is that one must use a .049 wrench to tighten and remove the head.

GallopingGhostler wrote:
There was someone who published their results in one of the other forums. He took a .049 glow plug adapter head and by carefully shaving away the seat until he had the same volume including the plug element cavity as the Cox head, obtained similar RPM's.

I remember that thread too, it is on the RCU 1/2A forum somewhere.
He first had to shave off quite a lot from the head in a lathe and then seal the threads with a silicon compound (permatex or similar) in order to match the regular heads in terms of power. So yes it can be done but the regular glow plugs are in general a major power loss, at least in the .049 engine size. One has to get up to around .10-.15 in order to not have a major advantage with the Nelson or Turbo style glow plugs.

If all out power is not that important, it does help to have heat ranges to play around with. The cox .050 RC runs and throttles well on the OS P4 as an example. No power loss compared to a stock glow head, while throttling is improved with a slightly warmer glow plug.

Thanks, Kris for pointing that out. I remembered reading it but not where it is from. I have hot generic 4 cycle plugs that work well with my larger engines. Similar to your observations, I've used a Mecoa head with a hot plug on my Norvel .061 Big Mig on Q-Tee. It provides spirited performance still above and beyond .049 reed valve engine performance.



Below is a photo of the top side of both heads. The Mecoa requires a .049 wrench to tighten and remove the head.



Here's how the engine looks with the Mecoa head mounted.

Another comparison, Medallion .09 head versus .074 Queen Bee:





The .074 head, bolt on compatible with the Medallion has a smaller volume space. I put it on the Medallion and it has better compression, like flipping the prop on a performance engine.

The .074 could possibly have potential. Now, we are cooking with gas.

Valentine used to make Turbo plug heads for all the Cox engines at .049 and up I think.
His .09 head also fits the Queen Bee and it worked a lot better compared to the stock head. Below is the stock Queen Bee head and the Turbo plug one from Valentine;