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Old May 29, 2001, 07:24 PM
Registered User
Singapore
Joined May 2001
86 Posts
Help in trimming the plane

Greetings,

Whenever my instructor takes off the trainer, he trims the plane so that it achieves level flight before he hands over the transmitter to me.

Now, do I have to trim the plane in full throttle or half throttle ? An optimally trimmed plane should flight straight and level or straight and slightly ascending?

Any help would be appreciated. Tks.
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Old May 29, 2001, 08:23 PM
Ascended Master
Sparky Paul's Avatar
Palmdale, CA
Joined Oct 2000
13,371 Posts
Adam, the trim setting depends on the airspeed, which is a function of the throttle setting.
Most trainer type airplanes are fairly tolerant of power, and a trim setting will be good for most of the flight..
It is a good idea to learn how little you move the trim lever for a good "feel" to the plane.
Practice several mistakes high..
.
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Old May 29, 2001, 09:53 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
20,843 Posts
Straight, level, and slightly ascending. When you make turns or other manuvers, you'll lose altitude, if the plane is trimed for slightly ascending, it will gain the alitude back. You might have to adjust the elevator trim several times during a flight as the battery juice runs down to maintain that slightly ascending angle.
hoppy
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Old May 30, 2001, 10:47 AM
Registered User
Singapore
Joined May 2001
86 Posts
Thanks for the help. Actually, I am purchasing a Zagi 400X. So will it be any different to trim than a Trainer?
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Old May 30, 2001, 11:14 AM
Balsa Kamikaze
Jensst's Avatar
Germany, NRW
Joined Feb 2001
536 Posts
This was useful for me when trimming my plane:
http://denverrceagles.freeyellow.com...t_trimming.htm

_Jens
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Old May 30, 2001, 06:09 PM
Our Daddy and Heli Junkie
Fred Bronk's Avatar
In Heli Wonderland
Joined Aug 1999
22,799 Posts
A flying wing will not fly the same as a regular airframe. If you can handle a trainer though you should be OK with the Zagi.
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Old May 30, 2001, 07:21 PM
Scott Black, Montreal
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montreal quebec Canada
Joined Sep 1999
1,254 Posts
You should NOT trim the airplane to climb. YOu don't want it to automatically compensate for a turn - that's the pilot's job and that is what you are training for.

A student should practise figure 8s, concentrating on keeping the the aircraft at a constant altitude whether it is turning or flying wings level. This cannot be done properly if the airplane is trimmed to climb. The student should also concentrate on keeping the 8 symmetric and centered with the cross-over directly in front of him.

This does several things. It gives the student practice in turning left AND right, it shows him the airplane in all attitudes relative to him i.e. coming toward him an and going away turning left and right, and it makes the student place the airplane purposely in a specific place in the sky rather than following it around. The student has to fly the airplane - not react to it.

Any model or full sized airplane should be trimmed to fly wings level (not turning) and constant altitude with hands-off. The amount of trim required as power changes is directly a function of the static stability which is a function of cg location. This applies to a flying wing, canard or conventional layout.

The more stable the airplane (fwd cg) the more elevator required for a given speed (in reality Angle of Attack) change.

If you trainer is set up to be very stable (fwd cg), you will have to re-trim each time you change speed. The up-side is that the airplane will recover by itself from a dive.

Learning how to trim is a good skill to acquire. As you develop confidence you can move the cg back until the airplane is neutral, like most aerobatic ships are set up. Then you won't have to touch the trim very much. In the mean time, there is nothing wrong with learning how to retrim.

sb
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Old May 30, 2001, 08:06 PM
Old school newb
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Iraq
Joined Feb 2001
840 Posts
I do enjoy trimming with my flash 4, it's really easy with those digital trim buttons. The buttons are activated when the are pressed down, or moved to the side (like a conventional trim). So, I just hold down the correct trim key until the airplane is flying strait (or level), and then i release! easy as pie
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Old May 31, 2001, 12:41 AM
HobbyKing
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Hong Kong, Hong Kong Island, Hong Kong
Joined Apr 2001
4,497 Posts
The only problem with digital trims is that when you are test flying and a plane is way out of trim, you can't just slide a trim hard over, you have to wait for it to move all the way over, on a hot plane, that can be a white knuckle experience. (Did it on a Quikee 500)
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Old May 31, 2001, 09:43 AM
Registered User
Singapore
Joined May 2001
86 Posts
sblack,

thanks for the detailed explanation. I will heed yr advice.
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