Cox 1/4-A Tank Capacities

Someone with a small syringe and access to these engines could measure the tank volumes. My Tee Dee .010 does not have a tank, and my only .020 is NIB. I do have a Pee Wee that I would not mind filling up. Maybe this evening (it’s 10.27am here when I write this).

I think most medical syringes even in the non-metric part of the world come with an ”ml” scale (millilitres), that equals cc’s.

If you watch online flight vids with stock tanks can help, least in run times that is the bottom line.
As a example I saw a TD .020 with a stock tank get 2 mins. / stock prop. The engine was running
good and steady.

Really it depends on what your flying, for RC 2 mins. is way too short of a flight, 5 mins. is a good run
enough time to enjoy all your flying tricks and practice or try new ones. My TD .020 with a speed prop for
higher than stock rpm will empty out a 1/2oz tank of fuel in 4 ish mins. That's 15cc of screaming go juice.  
TD .05 on muffler pressure will nix 30cc or 1oz in 6 mins with the Nano III per vid results. TD .010 with
with a 10cc / 1/3rd oz does 5.03 mins. per vid results from start to flame out Nano II with a speed prop.

706jim wrote:

1/2A Nut wrote:If you watch online flight vids with stock tanks can help, least in run times that is the bottom line. As a example I saw a TD .020 with a stock tank get 2 mins. / stock prop. The engine was running
good and steady.

I have used several Pee Wee's over the years (Hey, see my picture!). The fuel tank holds 2cc of fuel and that will run the engine for about 2 minutes. I used to fill the tank with 0.4cc of fuel for my free flight planes to keep them reasonably close by.

Thanks. Then I gather with stock prop we are talking about a minute per cc with at least the Pee Wee. Interesting that the Pee Wee holds 2cc. Then in reality it is a miniature 40% Babe Bee. Tee Dee tank appears to be slightly larger, which tells me the fuel consumption is slightly higher, which I would expect.

On 25% nitro and 25% Castor, Pee Wee put out 0.035 HP at 18,500 RPM (March 1976 Aeromodeller). Tee Dee .020 put out 0.055 HP at 23,000 RPM on 30% nitro. 0.055 / 0.035 x 2 cc = 3 cc. So, say a 1/4 oz. tank would probably be a good starting point for say a couple minutes of CL flight. (I don't think I could stand more, as with shorter lines to maintain line tension, will probably be quite dizzy afterwards.   )

706jim wrote:I owned a Berkeley "Baby Yank" free flight sort of RTF back in the early 1970's. Sent it up with a full tank because the engine sounded like it was going to quit. It didn't. My Baby Yank is still out there somewhere waiting for me to pick her up.....

Yup, know the feeling. I lost a Goldberg 42" Cessna Skylane with .049 Golden Bee guided by a Mattel single channel pulse proportional radio in North Little Rock, Arkansas in 1978. It was a calm before a thunderstorm. I tried to spiral it in when the winds picked up. It continued to spiral skyward up until it disappeared over the end of the field. Then raindrops the size of quarters started to pelt me. I was drenched before I reached the pickup. Plane probably landed somewhere in Kansas.