Alladin

I've got my ST G-90 well broken in with a 14X8 prop. I have this in a .90 size pattern plane. The only problem I have is I'm flying the plane close to full throttle to keep it level and manuvering well. What prop can I go to that will help me with more speed and vertical?

And which fuel should I use? I'm running 5% nitro right now.

NikolayTT

That 14x8 is too "heavy" for this engine as far as I have tried. For Speed try 13x7 and for 3-D-Aerobatics better is 15x4;
of course well depending on the Airframe construction and its weight.
Regards, Nick.

Bax

My Feedback: (11)

You can try something like a 12 x 8 or 13 x 8. The engine will easily turn up with those propellers and will give you more speed. You can run the SuperTigre G-90 in the mid-12,000's with no problems, as long as you have a good-quality fuel.

Alladin

Thanks I'll give it a try this weekend.

EL TEMUCANO

for pattern fly 14/8 (i put 14/8 on ucd 46 and i can do torque roll but on a .60 or .90 pattern plane used 14/8 )

for sport fly 14/6

XJet

My favourite prop for the G90 is the Master Airscrew Scimitar 13x6. Great static thrust and still plenty of speed. What's more, they're pretty economically priced and will withstand more ground-contact than an APC will.

greengoose

Hello Bax; I have a ST 90 that I aquired used and I changed the bearings, I used the stainless steel type and when it was all done there was a wee bit of crankshaft endplay, in and out movement type of play, the amount of play is extremely minute amounting to about the thickness of a cigarrette paper, is this permissible? You can pull on the prop spinner and turn it and feel a slight bearing drag to the rear bearing, you can also push on the spinner and turn it and you can feel a smaller amount of bearing drag, but no rubbing the conrod and crankpin on the backplate, in reality I think the rear bearing is doing its job in handling tractor thrust and radial and supporting the crankshaft at the rear (all 3 different rear bearing support functions) and the front bearing would support a pusher thrust from pusher props and electric starters and at the same time support the crank at the front the same as the rear bearing. all this accomplished without any desstruction or premature bearing failure from unknown factory preload on both bearings, Please give me your input about the endplay...thanx...

Bax

My Feedback: (11)

While we don't have a number for fore-and-aft play when the crank's properly-installed, it should be virtually non-existent. You may want to remove the drive washer, pull the crank as far forward as possible, slide the locking cone back on, and then install the drive washer with a propeller. If you still have fore-and-aft play, then you have bearings that are too loose.

greengoose

Iv'e reinstalled the lock cone and prop drive plate twice but it still has end play, is there a limiter on the front of the crankshaft meeting the lock cone, I looked and didn't see one. Thanks your help is appreciated..

Bax

My Feedback: (11)

When the crankshaft is installed in the engine, there's a bronze bushing ahead of the crank and behind the rear bearing. When you install the locking cone, it goes directly against the inner race of the front bearing. The crank will be firmly held in place. We feel zero fore-and-aft movement when the crank is properly-installed. Since you're using non-stock bearings, all bets are off.

greengoose

Bax, I got it, these bearings are a couple of thousands thinner than stock bearings but worth every penny over stock as they are stainless steel, all it takes is very careful thinning of the brass spacer to adjust the endplay and at the same time inducing a slight preload on both bearings. It takes about an hour (3 or 4 tries) but with a little patience they come out perfect and feel like factory but with stainless steel upgraded bearings which beats stock in the quality department...