Retiring and coming back to the hobby after a 15 year hiatus.

I have an interest in IMAC. Not 3D, just IMAC pattern.

I do have several questions for which I would like some input on before embarking upon the acquisition of a suitable aircraft.

What is an ideal aircraft weight and engine size?

Although somewhat theoretical, what “power to weight” ration makes an ideal IMAC aircraft?

Thanks in advance,

DR

33% bird
DA-85 on a can, pipe or muffler in that order
22-24 lbs

contest IMAC or at the flying field only Pattern IMAC?

My question was not 3D oriented whatsoever, just IMAC sequences. Well perhaps I should ask, are there any 3D requirements in any of the IMAC flying sequences?

DR

there is no 3d required its frown upon and cannot take place in between rounds or on take off

You need MORE than 1:1 thrust/weight ratio. In the upper classes of IMAC, there are maneuvers that require upline snaps (kills your energy and speed) and you must continue on an upline from there. 1.5:1 thrust ratio would be a minimum IMO. Picture a 24 pound airplane going straight up. Now do one positive snap. You just lost a LOT of energy. Now accelerate vertically and do a couple aileron rolls. Keep going up. That takes a LOT of power.

In the lower classes, you don't need that much power. 1:1 ratio is enough.

You don't NEED a 33% or 35% plane to get into IMAC. But, even though the money seams like a lot, you will spend 3X that much buying a 28%, then a 30% and finally moving into the 35%. The cost difference between a 28% (50cc) and a 35% (100cc) is about $1000-$1500 more. If you get into IMAC, you'll end up with a 35% eventually, so just do it now. You can buy a nice used 35% for around $2500. I have more than that in a 30% plane. Good deals can be had on used airplanes, if you can wait or spend some time hunting for the right one.


I think krayzc-RCU was asking:
Are you wanting to compete in official IMAC competitions? Or do you just want to dink around at the field and fly those types of maneuvers without actually entering a contest?

Thats 2 different planes. Or, same plane, but with different HP and thrust. Obviously, the contest plane will have a lot more thrust to pull off the big maneuvers. If you're just going to dink around at the field, you don't need that much HP, because nobody is judging you or deducting points if you can't pull off that big maneuver.

Keep in mind that more power is required in the mid-upper level of IMAC competitions than for performing 3D maneuvers. 2:1 power/weight ratio is what's really needed in Unlimited but you can get away with far less in basic-intermediate. Fortunately with today's designs it's pretty easy to economically get a high power-weight ratio.

Yep.. I'm on the throttle much more in IMAC than when playing around with 3d

The answer to your question is obvious and straightforward. The "ideal" airplane for Basic IMAC is the same as the "ideal" airplane for Unlimited, LARGE. You want as large of an airplane as you can afford and the rules will allow. And you want as much power in it as you can afford. The more power the better.