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Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 1:46:27 PM   
FLPilot


 

Posts: 82
Joined: 11/30/2007
From: Punta Gorda, FL, USA
Status: offline 		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
       Post #: 1

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 3:28:54 PM   
krayzc-RCU



Posts: 5970
Joined: 3/26/2002
From: Kannapolis, NC, USA
Status: offline 		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?

_____________________________

smooth as silk!

(in reply to FLPilot)
       Post #: 2

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 4:35:48 PM   
FLPilot


 

Posts: 82
Joined: 11/30/2007
From: Punta Gorda, FL, USA
Status: offline
quote:

ORIGINAL: krayzc-RCU

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

(in reply to krayzc-RCU)
       Post #: 3

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 4:52:50 PM   
krayzc-RCU



Posts: 5970
Joined: 3/26/2002
From: Kannapolis, NC, USA
Status: offline 		there is no 3d required its frown upon and cannot take place in between rounds or on take off

_____________________________

smooth as silk!

(in reply to FLPilot)
       Post #: 4

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 7:06:52 PM   
Rcpilot


 

Posts: 6556
Joined: 3/20/2002
From: Arvada, CO, USA
Status: online 		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.

_____________________________

Airplanes have expiration dates. It''s just not printed anywhere on them.
I''m not really an airplane pilot; but I did stay at a Holiday Inn Express last night.

(in reply to FLPilot)
       Post #: 5

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 7:31:48 PM   
Flyfalcons



Posts: 6100
Joined: 7/27/2002
From: Bonney Lake, WA, USA
Status: offline 		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.

_____________________________

Ryan Winslow

Cub flying - the new EXTREME SPORT!!! (evarrr)

(in reply to Rcpilot)
       Post #: 6

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/10/2008 10:00:50 PM   
exeter_acres



Posts: 6073
Joined: 9/22/2004
From: Johns Creek, GA, USA
Status: offline
quote:

ORIGINAL: Flyfalcons

Keep in mind that more power is required in the mid-upper level of IMAC competitions than for performing 3D maneuvers.



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

_____________________________

I would like to earn your vote for IMAC Southeast Regional Director

(in reply to Flyfalcons)
       Post #: 7

RE: Basic Aircraft, Engine, Thust to Weight questions. - 2/14/2008 10:41:58 PM   
les40


 

Posts: 382
Joined: 9/19/2003
From: Tucson, AZ, USA
Status: offline 		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.

(in reply to exeter_acres)
       Post #: 8

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