My real concern with usind the 70's was the amount of runway needed to get the thing airborne as well as seemingly not having enough power to pull up after take off, the one I saw fly the guy had to fight stalling it at full throttle after taking off for quite aways till it built up enough speed , it just seemed to me it was grossly underpowered and the only way he could really climb was to make several circuits of the field gradually gaining altitude with each circuit and then putting it into a dive to gain enough speed to pull up and gain altitude with authority.
I am aware of the do's and don'ts associated with twins and what happens when you lose an engine.
My intention for going with bigger motors is purely to be able to fly it with a bit more authority and and not have to fight off a stall on take off, the guy I saw fly his said it was way underpowered and that he had to really be careful on take off not to pull back on the stick too early or face stalling it, I dunno It just seemed to me that even at full throttle the thing seemed to be just lumbering around and the guy was fighting off a stall all the time.
I did youtube it and found a guy that was flying one with a pair of 90 twins in his and it seemed to fly alot better and pulled altitude without first making several circuits of the field
I'd rather have the extra power and not need it than need it and not have it
ORIGINAL: Dash7ATP
I love the B-25. It's a great looking plane and my ten minutes of stick time showed it to be a great flying plane with balanced controls. I''ll never forget that flight !
Now to the model... Increasing power in a twin is not always the answer to perceived problems. Just what makes you think you will need more power? This was a light bomber and not a fighter, so loops were not in it's flight envelope. I'm sure it would probably roll, but again, it's not something a pilot flying one woulld do very often, if at all. If you are concerned with single engine performance, more power just means a fastger spiral into the ground. Huh?
If you are familiar with twin engine planes (as i full scale multi engine rated) or models, then you already know that if you lose an engine, you must be at or above a minumum speed to have enough rudder available to compensate for the drag and loss of power on one side. If you are below that speed, more power won't save you as it just increases the need for more rudder. Trying to stop the roll that develops with aileron just increases the problem. Airspeed is the answer and lowering the nose and MAYBE reducing power to bring the plane back into balance is often the answer.
Adding a more powerful engine will increase your speed slightly, but does require an awareness of the problems mentioned above.
Good luck and keep us informed...
Dash