Super Tigre C35 Schooling

[Andre Ming]

I have a high regard for Super Tigre engines. However, there's only one that truly interests me and that is their C35 that was used in combat back in the early/mid 1960s. (Pre-G21-35 days.)

I had ONE Super Tigre: A C35 baffle piston R/C engine that I used on an ill-fated carrier airplane experiment. From that time (1968 or so) the engine stayed in my "box of engines" for decades, sans R/C carb. (Haven't a clue what happened to the carb.)

Anyway, a few years ago I got acquainted with Randy Daily, a former combat flyer that won Sr. Class at one of the Nationals of the 1960s. (But I've forgotten the year.) He was/is a Super Tigre fanatic in the worst way. (Said tongue-in-cheek on account of my affliction concerning Fox 36X engines!)

Anyway, during some of our chats he learned of my leftover C35. He offered to rebuild it for me as well as putting it combat trim. I "think" I recall him saying he could turn it into the same type of C35 he used to fly "back in the day". Well, I jumped at the offer. When I received it back I was elated. The pics illustrate the way it looks now. (Like new.)

I know nothing about the history of the Tigre C35, nor the variants produced from it. From what I can tell, Randy has put in a sleeve with a Schneurle-type porting and a flat top piston, along with a venturi insert.

Can anybody tell me anything about the combat version of the C35 such as Randy used to use, as well as several other fliers, back in the early/mid 60s?

I have in mind putting my C35 on the nose of a Wayne Welch "Zipper" kit that I have as a "Randy Daily" tribute airplane (Randy used a C35 powered Zipper to win the Nats), but I would sure like to learn more about the C35's role in Super Tigre's history time line.

Thanks for any input!

Andre

[Marty Hammersmith]

     I have the same engine. One is completely open port like the one in your pictures. The other has a center boss with a threaded hole for a throttle baffle. I'd love to use these on control line projects. Both of mine are in excellent condition (very clean) with excellent cold compression. I've already been warned from a person or two on this site that these will be very loud without mufflers. I don't know of a solution for that. How well do they draw fuel? The only thing I can do to the tank is a little ram air from the prop and flight. I'm running 8% nitro fuel with 21% oil for everything control line. Not quite half of that is castor. That should be good for the C35s I would think.

[Paul Smith]

These engines came out in the early 1960's.  They instantly became The King or Combat. Then the G21, which is the same engine with ball bearings came out and became the new king.  The older plain bearing C model is slightly lighter and a only (maybe) a little less powerful.

The crankcase changed almost every year due to ST's efforts to accommodate RC.  They run fine on suction, pressure or with a throttle.  They are not muffler-timed and any effort muffle them will result inn overheating and unacceptable loss of power.

You are better off putting it on a LOUD combat plane and, if you believe a muffler with help, get a OS FP or LA engine.

[Andre Ming]

These engines came out in the early 1960's.  They instantly became The King or Combat. Then the G21, which is the same engine with ball bearings came out and became the new king.  The older plain bearing C model is slightly lighter and a only (maybe) a little less powerful.

The crankcase changed almost every year due to ST's efforts to accommodate RC.  The run fine on suction, pressure or with a throttle.  They are not muffler-timed and any effort muffle them will result inn overheating and unacceptable loss of power.

You are better off putting it on a LOUD combat plane and, if you believe a muffler with help, get a OS FP or LA engine.

Paul,

Thanks for your input.

So did the C35 combat version indeed have a flow ported design? (i.e.No baffle piston.) The original innards in this case used baffled porting as I recall.

Andre

[Steve Lotz]

The baffle piston one was for stunt or R/C.

[M Spencer]

[Steve Helmick]

Actually...there was a G.21 .35 with a seperate front end (like a K&B .40) and a vertical intake, then the .35C (in combat and stunt variants), and last the monoblock G.21 series that included .29, .35, .40 and .46.   

I think I got my first ST .35C (combat) in 1964, and then a second. They seemed to vibrate a fair amount, so I wouldn't suggest them for a Ringmaster or Flite Streak unless some serious nose-stiffening was to be done. But then,  any Fox or K&B was much the same or worse. The good thing about the .35C was that they never broke, started well and put out good torque. Not really a high reving engine, I got best speeds with 9-8 Tornado nylons (Fox Blast 50% nitro, 116 mph), but I usually clipped them to 8.5" dia. for matches and ran Missle Mist, which was good for 105 mph, while a 9-7 Tornado was only good for 97 mph on MM. All speeds without streamers, of course.

I never ran mine without a venturi restrictor, but sawed it off shorter and repaired the bellmouth, with the idea being to keep from breaking the casting in the rare (sure!) event of a mid-air or crash. I got busy with the Dremel and squared out the base of the venturi in the case to match up to the rectangular port in the crank, which was also smoothed and cleaned up with the Dremel. One combat match, I mid-aired a Johnson CS, and the Johnson was destroyed, with just a few scratches on my ST .35C. Yeah, I felt terrible about that. 

As with any plain bearing, steel sleeve and cast iron piston engine, you need to use 25% castor oil. 10% nitro will make it run pretty well.  Steve

[Brian Hampton]

There's a test of the original open port baffled piston C.35 Stunt at https://sceptreflight.com/Model%20Engine%20Tests/ST%20C.35%20Stunt.html
Then a test of the later muffler ready flat piston with ST's TST porting at https://sceptreflight.com/Model%20Engine%20Tests/ST%2035%20RC.html

[M Spencer]

If you put the graphs overlaid , or plot on on the other , the P.D.P. has it .

This is on the shim under the sleeve flange . Muffled it stops blowback into the case . So not as great a power loss with a silencer fitted .
https://www.rcuniverse.com/forum/glow-engines-114/8470607-super-tigre-35-liner-shim.html
All the 21/35 , C 35 s & C 35 would benifit , silenced . and S converted 21 35s .

[Juan Valentin]

      I usually read everything I can on the Supertigre C.35 as is one of my favorite engines. This thread will help me on a project I have of an Inline Supertigre .70 twin I made. I had not noticed that the engines have subport induction. I measured the gap and it is.019 inch on the ones I have. The .020 inch shim should stop the Subport induction and I will be trying that on my twin. If you use the .020 shim on your engines you will have to lower the head on the liner by .020 inch to regain compression since your combustion chamber volume will increase with the shim. Removing the factory shim might not be enough and the head will have to be machined. I made a muffler for the inline twin to help quiet the engine and stiffen the joint between engines. I  fly control line and at this time i have an ST C.35 in my Flite streak using a Brian Gardner ABC P/L.   I `m building a C/L plane at this time but will try the shim idea on the Flite Streak later on to see how it helps with the noise.
                                                                                                                        Juan

[Dave Hull]

Very cool project, Juan!

I have a ST  .35C on a Combat Cat. Hard tank on pressure. Way more than a sport flyer needs....  Yup, loudness emanates from the exhaust hole.

A friend of mine specialized in "building" twins. Here's a snap of one of them.

Dave