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Old Jun 24, 2012, 08:51 AM
smoke is my wattmeter
Longview, Tx
Joined May 2008
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Why Does My Plane Need So Much Uptrim?

I've got one of these http://www.valuehobby.com/airplanes/...dy-to-fly.html. It's good flying airplane but pretty hard to keep it from being tailheavy, IMO. Mine's a bit heavy at around 53 ounces with a 3s 2200 and a 3548 sized motor. The reason I don't like having to use so much uptrim to fly level is that when I hover, it always wants to roll over or fall back on itself. I have a hard time using a little bit of elevator to consantly hover. Not sure if motor angle or anything can be adjusted to help. Perhaps a switch to change elevator trim for hovering? I'm not much on radio programming but I guess I need to learn. I'm using a Turnigy 9x radio.
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Old Jun 24, 2012, 09:01 AM
An itch?. Scratch build.
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South Wales U.K.
Joined Mar 2003
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You haven't mentioned the CG, I assume it is correct and not well forward ?
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Old Jun 24, 2012, 09:42 AM
smoke is my wattmeter
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It's actually about a quarter to half inch tailheavy. Still flies stably. I'd have to add weight to get it any better. Really don't want to.
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Old Jun 24, 2012, 09:47 AM
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A 3D aerobatic model should fly inverted with no or only the slightest touch of down elevator.. does it?
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Old Jun 24, 2012, 12:44 PM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia / UK visits
Joined Jan 2010
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What strikes as strange is that you say it's TAILHEAVY but you mention UPTRIM.
Usually with a tailheavy model - you would be putting in DOWNTRIM.

I can understand it FALLING BACK on itself ( that wording indicates model is falling back to INVERTED ). The tail would be pulling her back. If she was balanced correctly - then I would expect this to stop.

??
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Old Jun 24, 2012, 02:10 PM
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Neenah, WI
Joined May 2006
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Perhaps both ailerons are trailed-up (?)
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Old Jun 25, 2012, 02:54 PM
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United States, NJ, Ocean View
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here again try and balance inverted
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Old Jun 25, 2012, 03:30 PM
I want to go flying!
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Joined May 2010
400 Posts
Does throttle position in level flight make a big difference? If it does I would suspect thrust angle.
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Old Jun 25, 2012, 03:46 PM
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United States, VA, Virginia Beach
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I thought 3d planes were balanced tail heavy.
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Old Jun 25, 2012, 03:56 PM
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Quote:
Originally Posted by dedStik View Post
I thought 3d planes were balanced tail heavy.
Depends what you call tail heavy. Generally they are balanced about neutral, so that they fly upright and inverted without any pressure on the elevator, though some prefer a slightly more forward CG that still needs slight forward pressure on the elvator when inverted.
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Old Jun 25, 2012, 05:53 PM
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Quote:
Originally Posted by JetPlaneFlyer View Post
Depends what you call tail heavy. Generally they are balanced about neutral, so that they fly upright and inverted without any pressure on the elevator, though some prefer a slightly more forward CG that still needs slight forward pressure on the elvator when inverted.
Yep, and many fly the 1st flight or so a bit on the nose heavy side and work their way back. I have mine close to neutral and they fly inverted with almost no stick needed. I do not fly 3D, but I use 3D planes for aerobatics and I find that a balance near to what 3Ders use is good for me. That point makes landings easy for me also. They are going to stall unless I use a bit of power and fly them down to near touchdown. Power off will work if you "force" the nose down a bit to keep speed up. I like it that way.
Don
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Old Jun 28, 2012, 10:27 PM
smoke is my wattmeter
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Joined May 2008
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Got a few wind free flights in this morning. It flies level inverted. Anything half throttle or better doesn't change anything, inverted or upright. Ailerons look nice and level. Perhaps wing or elevator incidence is off a bit. Really not a big deal. I'd almost call this plane an aerobatic model and not really 3d. Ailerons are big and elevator is effective but rudder is kinda smallish. Hard to get it pointed back up when it falls to the side when hovering. This thing flat spins like nothing else I've flown though. Loses very little altitude when doing them. Afraid I'm going to burn the motor up doing them. It's so fun and easy to do them. Gonna swith to a 4s setup soon for more snap.
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Old Jun 29, 2012, 06:40 AM
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flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
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Might be something to do with the throws. Rudder needs to almost touch the elevators. Lots of elevator also. I find the elevator never stops moving when in hover unless you get it dead on vertical, but hard to get that point. In hover, all you depend on is propwash over the surfaces, so you need lots. I've found it helps to pulse the throttle. That way you get more prop blast over the surfaces.

Gord.
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Old Jun 29, 2012, 10:22 AM
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United States, FL, Lehigh Acres
Joined Aug 2011
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I go spin crazy with my stryker lol.
Try going up as high as you can and start the spins and count them , its fun and then you try to beat the old score . it gets interesting when you tru to squeeze just 2 more in lol.
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Old Jun 29, 2012, 12:03 PM
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USA, IL, Malta
Joined Jan 2004
732 Posts
Looks like your 10oz. over the recommended weight using the recommended battery. Where is all the extra weight?
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