Quote from: Motorman on October 02, 2026, 12:50:41 PMI'm dragging too much line .015 x 60. If you could see my field you'd understand why I can't risk a fly away. Besides I bought a 1000' spool of this stuff and it's just a sport plane.

I did crash it once and I glued the nose back on with some out thrust by accident so, dumb luck was working for me on that one. 

The venturi is one I made at .250" when I still had my venturi making machine. I know .218" was a big jump down but I'm working with tubing sizes here. I'll have to check part numbers on the stock one for this engine.

Fly-A-Thon tomorrow.
MM

I fly a Skyray 35 with OS 25 LA (only because I don't own a 20 FP). It is really too much engine for the Skyray. But I do run it with a 0.250" venturi where the effective area is 10% smaller than OS stock. Runs quite well IMO.

Also, if the goal is to slow down the Ringmaster, one might try an APC 9-3 prop (APC calls it a combat prop), or a MAS 9-4. I have never measured the pitch on the MAS but most report that the MAS props in general are a lower pitch than advertised. Maybe more like a 9-3.5 plus it is less efficient compared to APC sport props.

I have run both the APC 9-3 combat and the MAS 9-4 on a 25 LA on a Flite Streak, and it does slow the model down a bit. As I remember the MAS 9-4 was a little slower compared to the APC 9-3 combat.

Worth a try.

Colin

Just curious- Does the entire tank center of mass have to move, or just the location of the pickup/univent? Could a wedge tank simply be tilted up/down at the outboard end to get a consistant run?

Quote from: Michael LeGate on Yesterday at 03:58:50 PMJust curious- Does the entire tank center of mass have to move, or just the location of the pickup/univent? Could a wedge tank simply be tilted up/down at the outboard end to get a consistant run?

   No, you can move the pick up tube, and if using uniflow, moving that tube will affect the run. Tilting the tank to raise and lower it to change the run should work also, I would think. I've seen guys make custom tanks with the wedge off set to address the issue also. You just don't see it a lot.

  Type at you later,
   Dan  McEntee

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