mtntopgeo

My Feedback: (12)

Another member of the club attended a swap meet, & came across a couple of "small" engines.
Knowing that I played with the little stuff, (the only member who regularly fiddles with anything smaller than a .40) he bought both engines. "at $5 each, even if you didn't want them, I'm not out that much" he says to me. One engine was an old Norvel .061, still had a load of pinch near TDC, so, paid the man his $10 & went to the test stand. The Norvel was 'bout 1500 RPMs low for what I have come to expect with the same prop & fuel. Engine is probably near new condition, & just needs some run time. Had no idea what the 2nd engine was, other than a Cox. Looked here, & at the auction site, & I think that it's a "Medallion". Checked the swept volume, & it turns out to be a .09. The glow head was bad, so I chucked the old unit up in the lathe, drilled & tapped, then cut the glow plug seating surface down with an end mill until the plug was near flush with the combusion chamber. The engine came with an old generation 1 MAS 7x6 prop. Used that prop & 15% nitro fuel, & fired it up. Got 9600 RPM. Switched to a gen 2 7x4, & still only got 11,400 RPMs. OK, the glow head conversion surely took it's toll, & 15% fuel probably ain't right, but this number still seems very low. ............. QUESTIONS; Is this thing a "Medallion"??? Are glow heads available for it??? What is the "correct" prop/fuel combination??? What kind of performance (with everything correct) can be expected??? ............. Even with the "as/is" set up, the engine should be able to handle a 20-to-25 OZ plane quite nicely, I think??? .................. George K.

Jim Thomerson

Aeromodeller review (May, 1963) gives 12,900 on a TopFlite 7 x 4 on standard Cox fuel. I'd guess your glow head is knocking it down some. I don't know if anyone is making 09 glowheads. I'll check and see if I have any Medallion heads. They are a lower compression head than the TD 09 head. I'd suggest going down to a 7 x 3 prop, and 15% fuel should be OK. I run my TD 09's on 10% nitro fuel, and Cox 7 x 3.5 props, and they run to suit me.

MJD

My Feedback: (1)

It is a Medallion .09. The milder engine between it and the TD .09. The official Cox .09 prop was/is the 7x3.5. A 7-3 or 7-4 is typical. Peak power is in the 16,500 range. Fuel - typical 1/2A sport brew of 15% nitro and 20-23% oil, all or a good chunk of it castor will make it happy. 15% is a very good nitro level for this engine. It will survive on regular sport fuel with 18% blended oil, but will be much happier if you add some castor. Your rpm seem down, but standard plug conversions can do that. Check Xenalook's site for plugs. Oops, guess not.

[link=http://www.mh-aerotools.de/airfoils/documents/cox_medallions_instructions.pdf]Medallion instructions[/link]

[link=http://www.xenalook.com/?id=696654&page=home&search=09,.09&logic=1]Cox parts, but alas no .09 heads[/link]

hllywdb

Hi George,
Can't beat the price. I usually get 13.5 -14 with my medallaion 09 on a MAS 7X3. That's with a MECOA head adapter for standard plug and the RC throttle sleeve. But I usually run Sig Champion 25%. MJD is right, they like the castor.

Vintage Glow Engines has a Medallion Cox 09 head on auction right now for under $12 buy.

Duane-RCU

My Feedback: (5)

I have a new Cox #2102, says TD .09, would that work? I don't have an .09....cheap/trade?

lildiesel

K&B MECOA is promising .09 glowheads some time in the future. Good luck and patience will tell. I love diesels I've never had any glow plug problems.

mtntopgeo

My Feedback: (12)

Guess that I'll leave things "as is" (on the Cox) for now. Even though power is down, there's more than enough to haul a foamy glider around. ...... The little Norvel will be getting a home in a Mountain Models SWITCHBACK GT. ............. George K.

gcb

Whenever you get around to it, you might try up to 25% nitro and some different heat-range plugs. Also check which size plug you need to make it flush with the combustion chamber on the adapter. It should not protrude into the chamber, nor should it be recessed.

Good luck with it.

George