Hi 1/2 A guys
 I hope you can give me some info.  I built ST60 stunt ships for 20 years and have been in electric ( 60 size) for the last half dozen years or so.

I thought it might be a kick to build a half A. I have started a Dick Mathis "Pinto"  (nice little plane)  A good friend gave me a new in box Cox  TD 049 for the project. When I look at it I see the exhaust ports are front and back as opposed to on the side as I expected. I looked for TD's on the net and it appears  some came through with side ports and some with front and rear ports.

Can this motor be used on a full body ship without oil soaking?  Suggestions?

Oh ya, I'm finding building small stuff challenging-but fun

Dick

          Optimally, having the ports aligned as your engine is offers the best performance. This can be changed using shims under the cylinder. However, without seeing the engine to know exactly where the piston is at TDC vs the plug landing, this could also alter your performance slightly. Darrell Albert purchased much of the Kustom Kraftmanship  goodies offered for Cox engines. He had these shims offered in .001"-.003" thickness. Darrel is a member of Stunthangar on pg 21 of the memberlist. While it's always a known fact that mufflers do just what they're supposed to do, they generally rob power. However, a lot of testing has been done on some of these and surprisingly the results were not as poor as originally suspected.

                If these are no longer obtainable, my suggestion would be first to use a timing shim that Cox International or Matt at EX Model engines offered. I gave a quick look and didn't see them but that's what they were referred to as. They offered them in .010"- .015". No telling how the ports will end up just something that may work. The other option is to against my beliefs is to use a muffler. Keep in mind, the TD uses sub port induction, therefore it won't work properly unless a shim is under the cylinder to block it off.  This is required so that spent gasses don't go back into the case robbing power and performance. Both EX Model engines owned by Matt, and Cox International owned by Bernie offer mufflers. Any of the  mufflers they would offer for a .049-.051 fits your TD. The only exception would be if the venturi of the TD interfered with the circumference of the muffler and either one of these fellows will quickly respond to a e-mail.

           

Frankly, the Tee Dee may be a bit much for the Pinto. Search for a Medallion in top shape. Or plan to use LONG lines! Probably a 1 1/4 ounce tank and 52" lines with a 5x3 prop. Epoxy the engine compartment and let the oil go where it will. The port configuration you have is the ideal. Don't mess with it or add a muffler.

A really good combination would be a muffled Norvel Big Mig  .061 with an APC 6x2 prop on 10% fuel. 3/4 ounce tank is all you would need, they are much more frugal than the Cox engines. Mind you I am the ultimate Cox fan, but will face up to reality. That would fly on 45' .008" lines at a respectable speed with good line tension.

Guys

Thanks so much for your thoughtful replies. I learned a lot . I have not run a half A since the 1950's and then it was OK Cubs.

Since Dick Mathis used the TD I think I'll stick with it.  I'll just paint with epoxy and let it rip. Base on your comments it should be Ok . Just a fun thing to do to fill time.


Again, thanks for the advice

Dick

A TeeDee .049 can run on suction very well if you just downsize the venturi.  Put pins of wires in the spray holes and fill it with JB Weld for a similar epoxy.  Then pull out the pins and drill it to a smaller size.

Seriously Dick you are getting good advice...yes for sure the TeeDee will fly hat pinto...but it is a pain to tame and will screw you into the ground post haste....many folk say...well... just use longer lines.  That works a little until the line length overcomes the light planes ability to stay pointed out of the circle...thunk on that a tad
you been offers a Medallion front carb body sans  NVA..                   I have two NVA willing to mail one free to you

many manny of us flew and have great nostalgic memories of our pintos...we want you to smile and have a blast...I love my TeeDees...but truthfully those buggers can be a pain without a bladder

Guys--you need to go look at the Pinto before y'all start with the endless mods. The stock design has an inverted engine and no bottom cowl. The engine sits in a bathtub. If you just brush the inside of the engine compartment with epoxy (I believe Keith was suggesting that) and then paint the thing--I would use KlassKote--you should be golden. And, no, none of the wood structure is so close to the exhaust ports so as to be likely to burn the finish.  I've seen a couple of these fly and was impressed. One had a medallion. Not sure about the other. I grabbed a Hobby Fasteners kit when I came across one a year or so ago. So I'm looking right at the plans. Ain't no cowling in the way. At most, you might scallop the fuse edges there--but if your exhaust ports are front and back the cylinder is still a quarter inch or more from the firewall. If that worries you, just stick on a piece of tin stock right there. My thought is this, if a talented designer was happy with it, it's likely I would be too. (Did you ever see a good rendition of his Excalliber? Wow!) Now, if you go off on a tangent and add a Nobler-looking abomination to the front of the thing, then you have caused a whole new set of issues. Why go there....?

What Dan is not realizing is that if you try to go sidewinder on the skinny full fuse job like the Pinto your tank position will be terrible. You can't line up the fuel mass with the needle in the inboard/outboard direction. So you'll have to set it screaming lean on the ground only to have it go rich in the air. I have had to fix a couple of OPPs (Other People's Planes) in the last couple of years for just this problem.

Don't worry about the orientation of the exhaust ports. It'll be fine.

I just made up a Pinto tank to the Mathis plans for my fellow club member, Mustang Bill. He's got one Pinto he likes and has ambitions to build another. If the tank doesn't make sense just from looking at the plans, then read the article on how you fill it up. It only has two tubes, and no, you don't have to take the line off the needle valve to fill it. My thanks to Mustang Bill for pointing that out to me.

You picked out a great plane. How you have fun with the project!

The Divot

PS--You might want to look up the Barry Baxter article on his 1/2A Stuka in the AMA archives. There's useful info in it for running that engine.

All the guys have given good advice.  My experience with the Tee Dee is to use a lower pitch prop.  I run 6-3 props on mine.  I still Have my Pinto that flies great with my Tee Dee and 6-3  APC prop on 35 foot lines.  Could probably go to 40 foot smaller dia lines as mine I use .012 cable 35 foot center of plane to center of handle.