Thrust, speed, Horsepower?
 

Ok I need your help.

What's the right blend of thrust to weight ratio for excellent vertical climb while being careful not to overtorque and snap roll on takeoff.

I've set up several calculations and it seems like a 1.3 to 1.5 thrust to weight ratio would be manageable.

>I like speed, but I also like vertical.

Are you guys running any higher- thr to wt- numbers ?

I can prop my engines up or down, but want to get a ballpark to target. I've got a long winter ahead of me, but I can run my engines to tweak the rpm's, the props, the horsepower and the expected speed and static thrust numbers for next spring!

I have 4 engines/planes:
1.08 on a Goldberg Chip, Os.61 on a GP Corsair, OS .40 La on a SuperSportster (20 size) and a Magnum .25 on a mini scratch built Mustang (34" w.s.)

I prefer APC's but am open-minded here as well.

thanks,
jw

that old chestnut!!
 

Hi,
Just my opinion but try looking at a higher thrust to weight ratio...somewhere around 2:1 or 3:1 which is commonly seen at the TOC's. Too much power need'nt be too big a problem if your sensible with the throttle stick!
Can't help much with prop sizes for glows though!
Happy Flying

thrust power, etc.
 

You'd recommend easing it up rather than slamming it full throttle?
I've noticed I do better if I let most all my planes roll out on a longer takeoff run at 3/4 throttle, in general, but I haven't really had good power plant potential until recently.

Thrust, speed, Horsepower?
 

For sport aerobatics thrust to weight of 1-1 is fine and will give you almost "out of sight" vertical, for 3-D 1.5-1 is the minimum.:D

Re: Thrust, speed, Horsepower?
 

What's the right blend of thrust to weight ratio for excellent vertical climb while being careful not to overtorque and snap roll on takeoff.

Its the left stick, rudder and proper use of the throttle on take off. The snap on takeoff comes from not enough airspeed and too much elevator.

No need for calculations or reprogramming a G2.

Only actual flight experience will set you free.

Thrust, speed, Horsepower?
 

I've never seen a plane that couldn't take off just because of too much power. I have seen planes that are overpowered that have snapped in on takeoff, but it's usually caused by #1, operator error, #2 too much weight, and #3 the CG too far forward. From the landing side, if you have too much power and the wrong prop, the plane may not want to slow down enough to land, but this can usally be corrected by decreasing pitch, increasing diameter and proper low end tuning (or just killing the motor on final). Given the right equipment & design, 2-3:1 T/W is doable, and can fly very well, but it does typically take some throttle control to prevent damage. 1.5:1 seems to be about right for good areobatic performance, and 2+:1 is required for any serious 3D. I've played with thrust to weight, theroretical top speed, measured in air RPM & speed, etc. and after all that, nothing beats grabbing a handful of different props and flying them to find the one that works best.