Super Tigre S40 ABC Schneurle Ported

[David McComb]

Hey all, I just bought a NOS Super Tigre S40 ABC, never run or mounted on ebay. Got it for $95 the opening price as I was the only bidder. I was floored !! . I couldn't believe I got it that cheap.
I then bought a performance C/L venturi and a couple of Higley style needle's and ST valve assy. for it. I also have an original ST header pipe with tuned muffler for it.
Gonna mix up a batch of original recipe' Missile Mist for it. But I'll break it in on 5% Nitro x 25%(Blendzall 460 Castor)
And for all you G21-40 hound's out there, tests show it out performed the G-21-40 even with a muffler.
What I can't figure out is why none of you guy's didn't bid on it ??
Have a good one all ! .   David B. McComb

[Dave Rigotti]

Because ALL of my stunt props are electric?

[Dave_Trible]

Hey all, I just bought a NOS Super Tigre S40 ABC, never run or mounted on ebay. Got it for $95 the opening price as I was the only bidder. I was floored !! . I couldn't believe I got it that cheap.
I then bought a performance C/L venturi and a couple of Higley style needle's and ST valve assy. for it. I also have an original ST header pipe with tuned muffler for it.
Gonna mix up a batch of original recipe' Missile Mist for it. But I'll break it in on 5% Nitro x 25%(Blendzall 460 Castor)
And for all you G21-40 hound's out there, tests show it out performed the G-21-40 even with a muffler.
What I can't figure out is why none of you guy's didn't bid on it ??
Have a good one all ! .   David B. McComb

Because it's not been used as a stunt engine and may not be suitable for stunt.  Never the less us know how it works out.

Dave

[Steve Helmick]

Should be good for Navy Carrier.  Steve

[David McComb]

I have a Sterling Grumman Guardian carrier kit and a Walter Umland made Sterling Spitfire. Might put it in the Spitfire. I have a NOS Fox Hawk 60 that should work in the carrier plane.
The engine will fly stunt just fine without a pressurized tank and properly tuned.

[Rusty]

Just out of curiosity, have you compared the weight and fuel consumption of the G21 40 and the S40 ABC?

[M Spencer]

Neverknow untillyatryit . https://sceptreflight.com/Model%20Engine%20Tests/Como%2051.html lok at the COMO 51 , here . Near the same thing .

Very high timed , though .  The Olde .175 , or .180 intake , might get it sucking & holding . ( add .1 for a spraybar thru it .)

Probly make a better Q 40 pylon motor . but after an hour , try a 12 x 6 , and a 12 x 4 three blade . And seehowitgoes .

AND , THAT tests a ' Blue Head ' ? Think ive got a report , with one that looks to be sane stunt timing . So you might be in luck . Ifitsa silver headed one .

[David McComb]

Not too worried. I'll have fun and play around with it.
Pictures below.

[David McComb]

I have a couple of Xoar 10-7 WWII Beechwood 3-blades. you have to down size an inch when going from 2 to 3 blades. Recommended prop for the S40 ABC, I think is a 11-7.

[David McComb]

I'd like to keep the rpm's down a bit to around 14000.

[David McComb]

Master AirScrew makes a 10-4 3-blade.
Correction to last post, 13000 RPM's .

[GERALD WIMMER]

Hello I ran one of those in a Genesis nearly 40 years ago now. My brother ran a S45 in a similar sized model (Olympian a Dave Wright design) replacing a G21/46 . Both engines ran very well when set up for the job, similar to an LA46 but better. More potential power there then a ST 60 but needs work to control it, like a Vf.

[David McComb]

Thanks for the feedback fellas. I'd like to expand a bit on fuel and performance. First I'm just an average stunt flier but I started playing around with 2 cycle glow engines when I was around 12 yrs old.
When an engine leans out too much or stalls on a climb, our first reaction is the needle valve setting or "it's a bad carburetor" or Porting etc. With control line always remember 1. Centrifugal force
always pushes fuel to the outside wall of the tank. 2. Forward inertia of the plane causes the fuel to be pushed Aft in the fuel tank. This means that the fuel will always be in the right rear of the tank
in a control line plane. So the fuel line pickup should be a stiff brass tubing ending at the right rear corner of the wedge shaped tank. This will ensure a steady uninterrupted fuel flow no matter what the aircraft is doing. Clunk pickups are not as efficient. No extra tank pressure is needed. Mixture set rich at standstill. Then sweep the plane upward with the engine running. The engine should lean out and speed up immediately. This is the 2 to 4 cycle break you will need for a vertical climb. It's important to note that a higher performing engine like the S40 ABC will have a much greater increase in speed during this 2/4 cycle break and more pronounced if your running 25% nitro x 22% Castor. This oil content provides the best bearing protection hands down.
So before you over analyze the problem, check the fuel tank setup and the fuel you're burning.
Have Fun playing around with the Airplanes !!
               David B. McComb

[David McComb]

Post script note: I never ran any less than 15% nitro and 22% castor oil. Engines always ran great on it. If your worried about gumming up you can always squirt a little fuel in the exhaust port and turn over the engine after shut down.
Methanol is an amazing cleaner.
I still love good ole FOX Missile Mist.
           David B. McComb

[Peter in Fairfax, VA]

Curious, why is the fuel at the rear of the tank? 

I wonder if the plane speeding up / slowing down and climbing / diving would have some influence on the fuel.  For example, during the cloverleaf, which comes near the end of the pattern when fuel is scarce.

[David McComb]

Centrifugal force always pushes fuel to the outside wall of the tank. If the fuel is very low there could be an interruption in the fuel flow when the plane comes out of say, the top of a loop because you also have to take into account the force of gravity.

[David McComb]

Forward inertia of the plane causes the fuel to be pushed Aft in the fuel tank.

[john e. holliday]

Need to do a search for the videos the Tulsa Glue Dobbers did years using a clunk tank on the plane.  Amazing to see the way the fuel moved and yet stayed to the out board side corner of the tank and in the rear.  Even in downward portion of maneuvers,   May have to go to Tulsa Glue dobbers Control line site,

[Paul Smith]

Curious, why is the fuel at the rear of the tank? 

I wonder if the plane speeding up / slowing down and climbing / diving would have some influence on the fuel.  For example, during the cloverleaf, which comes near the end of the pattern when fuel is scarce.

In RC and CL scale and carrier, the tank is not run dry.  Hence, the problems you have mentioned don't happen.  In stunt and other CL events, the engine run needs to be good to the very last drop, which is a challenge.

[Lauri Malila]

Forward inertia of the plane causes the fuel to be pushed Aft in the fuel tank.

Only during acceleration.

[Dan McEntee]

Forward inertia of the plane causes the fuel to be pushed Aft in the fuel tank.

    As already mentioned, only during acceleration from a standing start. Search around on here or just do a google search for someone's video of a profile model that has a Sullivan tank mounted, one of those small key chain cameras mounted on top of the wing at the root,  and with the red fuel in the tank you could see exactly what happened to the fuel load during a pattern.   Whoever it was flew a pretty nice, smooth pattern and the fuel load and clunk moved very little, and is very clear to see how the fuel load is used and sort of goes down from full to cover the whole outboard inside of the tank and then as it runs down the remaining fuel just goes to the back at the pick up tube as it's used up. That's one reason to not over do rudder and engine offsets and have the model flying at too much of a nose outward yaw. If the corner of a plastic tank is out farther than the rear corner, that's where the fuel will run, just like on a speed or racer coffin style fuel tank. 
   Type at you later,
   Dan McEntee

[Brett Buck]

Forward inertia of the plane causes the fuel to be pushed Aft in the fuel tank.

    ?? What is "forward inertia?"  I think you actually mean "forward momentum", but that will not keep the fuel at the back of the tank, you have integrated one step too many. 

      The fuel goes where the acceleration and shape of tank drives it, and it goes there fast enough that you can ignore the transient for most purposes (as demonstrated by Bob Reeve's in-flight tank videos).

   Doc's observation is generally correct, because there is about 2.5Gs lateral G (along the body Y axis) on a typical stunt plane in steady circular flight. There is 1G up and down, so the fuel surface is maybe 68 degrees from horizontal. It moves fore and aft under fore and aft acceleration, and up and down based on up and down acceleration - both of which are substantial at times - up and down due to maneuvering and abrupt pitch rotations (the tank is not at the CG, so pitch rotation couples into Z translation), and fore/aft due to drag, engine acceleration, and the other factors in speed recovery.

     Brett