ORIGINAL: Rcpilet
If you don't know what I'm talking about--and you've never listened to a glow engine run out of torque--then there's nothing more I can say to describe the sound and feeling to you. They just DO.
You have to just listen to it. You can tilt your head towards the plane and listen to a glow engine slow down and loose power on top of a big IMAC loop or a long vertical upline. I've heard all of them do it and guys will swear, "Listen to that engine--it's pulling like a freight train!!" No it ain't. It's falling all over it's face every time you pull back on the stick and put a heavy load on it.
I don't want to argue or get in a fight. You say they run good and have plenty of torque, and I hate 'em because I don't think they have enough consistant torque to keep swinging a big piece of lumber.
...I still use them, but only .75 size engines on little 3D planes.
Rcpilet, I do not want to get in a fight either. But, do your .75glow on little 3D planes run out of torque? What do they weigh?
What I am getting at is if the plane is properly powered and tuned (correct prop and mixture settings, cooling) so there is no heat build or leaning up under load, than it does not matter if it is glow 2 or 4 stroke or gas or electric. They all will go straight up without running out of power.
Around sea level with right fuel and prop, pitts ect.....
With a Moki 2.1 on pitts plane should weigh about 14 pounds or less
With OS 1.6 plane should weight about 12 pounds or less
With OS 1.08 plane should weight about 10 pounds or less
With YS110 plane should weight about 10 pounds or less
With OS .91FX plane should weigh about 8 pounds or less
With SA100 plane should weight about 7.5 pounds or less
With a ST75 plane should weight about 6.5 pounds or less
With OS46FX plane should weigh about 5 pounds or less
With OS25FX plane should weigh about 3 pounds or less
With 50cc gass/pitts plane should weigh about 18 pounds or less
With 40cc gass plane should weigh about 14 pounds or less
With 26cc 1.6 gass/pitts plane should weigh about 10 pounds or less
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Put another way...
Power your plane so it can blast out of a hover. The greatest load you can put on the motor is static (unless you are in a back slide). If you have your motor tuned so that you can run wide open for 5 min on the ground without the motor losing RPM and the motor has fuel delivery such that it is not going lean or running hot going vertical, what makes you think that it will lose RPM (or power) while the plane is going straight up?