Just won a Cox .15 Sportsman

Nice looking Sportsman , I was looking for the video of mine running some years ago but its been removed Anyway it is a nice easy starter and ran good just a test run no plane for it though. I am sure you will enjoy the engine would love to see you get it mounted on a plane and give it a whirl !

It's seems hard to find a Sportsman in decent shape. I have one that is junk, bought years ago. I like the way the Sportsman and Spacehopper look. The .15 must be awfully loud.

Hello friend GallopingGhostler , congratulations on your new acquisition!
I have two Sportsman .15, I bought them separately, each one from their own owners, they are very little used.
I made some modifications, without damaging the original parts, so if you remove the parts you put on, you can return it to its original state.
What I did was adapt the carb from a .30 4 stroke engine, just use the barrel air valve to get control of the rpm and that's how I converted them to RC.
I also made a muffler for one of them, as it is very noisy, it really makes a lot of noise and with the muffler it is a pleasure.
Here I leave some videos.
I have dedicated part of this work to Mr. Dale Kirn, who was the creator of the Stortsman .15 engine.
A shout out to my friend Brad who gave me the idea to put in an air valve for engine control.
P.S. I love your cover photo!! LLLLUUUUPPPPIIIINNNNN

Congrats, George! I'm sure you will have it looking a treat when you get your hands on it. I've always thought the Sportsman had a sleek and fast look to it.

I have one, never run, that likely will stay that way. I expect it will end up in some estate sale for $10.

Thank you all, for the encouragement! Helps me to know I made the right decision to purchase it! More to follow when I receive it.

MauricioB wrote:I have two Sportsman .15, [...] I made some modifications, without damaging the original parts, [...] What I did was adapt the carb from a .30 4 stroke engine, just use the barrel air valve to get control of the rpm and that's how I converted them to RC. I also made a muffler for one of them, [...] Here I leave some videos. I have dedicated part of this work to Mr. Dale Kirn, who was the creator of the Sportsman .15 engine. [...]

Eses videos son muy interesante, también tu obra propria como un mecanico ¡es muy excelente! These videos are very interesting, also your own work as a mechanic is very excellent!

MauricioB wrote:P.S. I love your cover photo!! LLLLUUUUPPPPIIIINNNNN

Lo me gusta mucha la revista de Lúpin porque la ayudame comprender el idioma de español. I really like Lúpin magazine because it helps me to learn the Spanish language. Yo lo leo a menudo. I read it often. También lo dame una razón que reírse. Plus, it gives me a reason to laugh. Tengo muchas gracias cuando en otro foro encontraba esa enlace de red. I am very thankful when in another forum I found that network link.

MauricioB wrote:

Yo veo un ganador potencial para el próximo concurso mensual del motor de Cox. I see a potential winner for the next monthly Cox Engine Contest.

Looks like some fun for sure George!
Thank you Mauricio~

I have snagged two Olympics and 2 Sportsman's - 3 with vintage aftermarket throttle exhausts.
Inner half circle shells with outer throttle sleeve.

Cox .15 aftermarket throttles:




Cox slide throttles.

1/2A Nut wrote:I have snagged two Olympics and 2 Sportsman's - 3 with vintage aftermarket throttle exhausts. Inner half circle shells with outer throttle sleeve. Cox .15 aftermarket throttles:

Brad, love those aftermarket throttle rings, they permit SPI to work effectively yet allow the engine to properly idle. Also, yours have the snap starter, was this aftermarket, too? Too bad Cox discontinued the Sportsman (and Olympic).

I gather that it was a cost cutting measure, the Tee Dee derivative, the Medallion .15 was cheaper to produce since it used the base parts (crankcase, crankshaft, and upper parts with one less bypass) from the Tee Dee with less expensive and simpler machining, simplified venturi system, with at least the same power as the Sportsman.

thank you for your comment.
The Sportsman also has another extra advantage, it can rotate the propeller clockwise or counterclockwise, when experimenting with models and propellers, the engine is a great contribution.
You know, my Sportsman has never been planted, it always runs perfectly, it doesn't need to pressurize the tank, since the suction generated by the crankcase is more than enough in sharp climbs.
I like the Sportsman! ... making the silencer is another great advantage, you can fly it in any club, since the desibeles are allowed and it's nice, I DO NOT DISTURB the marching sound of it.
A few years ago I presented it in the Engine of the Month, but it did not get many votes, I suppose that many people have not used it with all the possibilities that this engine has, I think that if you have a Sportsman .15 soon, you will have an engine with many possibilities of use.
Maybe I'll present it again in the engine of the month, who knows!

here is a model airplane enjoying a Comanche with a Storsman .15...surely it will take many of them back in time.
Although I was born in 1971, I feel that the time from 1958 onwards regarding all these Cox creations, must have been a great encouragement to many enthusiasts, I think it must have been a wonderful time for the hobby and for Cox!

Today It arrived, now have it in my hands. It sort of resembles a rear rotor Tee Dee, if Cox were ever to make one.

It has new like compression indicating that it was probably run, but not much. The plier marks on the prop thrust washer isn't as bad as it appears in the photos. The burrs will clean up nicely with some very gentle filing and rubbing down with Mother's Mag and Aluminum Polish. It resembles a rear intake Tee Dee, does not use SPI, which is interesting. Entonces el silenciador hecho por Marcio estaba práctico porque el motor no tenga SPI. Then the silencer by Maricio was practical as the engine has no SPI.

The top fin on the steel cylinder does show some pliers tooling marks, but not bad also. Some gentle filing of the burrs on the fin and touch up with bluing with clean that up.

Someone did clean and oil it because it shows no Castor drag. The glow head looks new without any clip marks on it.

Regarding loudness, I imagine it will probably be as loud as a Testors .19 Red Head or OK Cub .14/.19. Anyone who flies unmuffled control line aircraft will probably feel comfortable with its sound.

More to come ...

Went to the garage digging in my desk drawer.


I found a Hayes AL-15 long motor mount that fits this Cox .15 Sportsman (el Deportista ). Don't mind the background engine clutter (no necesita preocupar porque lo no importa ).