I have plenty of larger and smaller engines, but I only have one .25 engine. It's a .25 FP on a Flite Streak ARF.  I'm feeling pretty timid in pushing my learning curve, as I don't want to break the plane and not have another beginner plane on standby.  I thought that, since I just bought a nice little belt/disc sander, I'd cut out two or three Flite streak kits and have a fleet on hand so that I'll be bolder in pushing my learning curve.  But I don't want to pay eBay prices for another .25 FP to have ready to go.

I do have a Super Tigre G25 X-Serie ball bearing engine that's not doing anything right now.  It's a R/C engine, and I thought I'd just run it with the R/C carb for now.  I don't want to drop money into a custom made venturi with spraybar assembly.  I'm planning on running an APC 10x4 prop, as that's what I am running on the FP right now.  So, my question is this. Do I 1) Wire the throttle full open and set the needle to get the RPM I want, or 2) Peak the RPM with the throttle wide open, and then set the throttle back to the RPM that I want.

I know that either way, it won't be as consistent as a proper C/L venturi, but I'd think I'd want to peak it out at WOT and then set the throttle to the RPM I want, since this would give me the better fuel economy.  What do Y'all think?

Mark

I would choose a setting somewhere around 2/3 throttle to start, set your RPM by needling, and see how it flies.  Then adjust the throttle and needle from there.  If it has a nice lap time at level but seems to lose power in the maneuvers and overhead then the throttle's closed down too much and it's too lean.  If consistently runs away then you're launching too rich, or it's overheating, or you have too much prop (probably) -- try closing down the throttle a bit.  If you can't find a "happy place" with these instructions, then either the engine isn't suitable, or I don't know what I'm talking about (I haven't tried this method on that engine).

Depending on how open your venturi (or throttle) is, you can get markedly different flights with the same launch RPM.  I'm guessing that on that engine you want to be in a quite wet 2-stroke; that should give you some pick up on the corners.

It may just be too much engine for a Flight Streak -- something that's Flight Streak like, but scaled up to 500 square inches may be happier.  It may also prefer to turn a bit faster with a 10-3 prop.

If you're going to copy the Flight Streak, add two or three inches between the wing and tail, and an inch or so to the nose to balance it out.  Or just build Sig Skyray 35's.  The Flight Streak is a great fun plane, but a bit short-coupled for stunt (not that a good pilot CAN'T make it work -- it's just easier if it's longer).