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Old Jan 09, 2012, 10:59 PM
Honeybadger don't care...
Luv3d's Avatar
Orlando, FL
Joined May 2010
1,836 Posts
Trimming question

Anyone own a JR 9503, and use Differential to make rolls more axial? I have a friend who is helping me retrim my 330SC, and as we are stepping through a Peter Goldsmith trimming guide, and it talks about differential based on the airplane 'walking' (45 deg upline with a full aileron deflection either direction)- the guide talks about decreasing the up aileron if it walks one way, but decreasing down aileron if walking the other way. A friend suggested we just adjust the TRAVEL ADJ menu to reduce the deflection in the needed direction.

My question is this- Diff. Aileron or TRAVEL ADJ- which do you prefer, and why?

Thanks for your thoughts!
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Old Jan 09, 2012, 11:14 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
27,677 Posts
Don't need it. 3DHS planes are designed not to need differential.

SteveT
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Old Jan 10, 2012, 01:10 AM
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BOBBY1017's Avatar
Petaluma, Ca.
Joined Mar 2006
706 Posts
Quote:
Originally Posted by BOBBY1017 View Post
This is close to my exact setup, hacker, batt's Rhino 3700 25c, I keep the end of the battery even with the front of the wing tube.
Quote:
Originally Posted by kalmon View Post
Really? my batteries are shoved way up in the nose. I mean the back of the battery is only 3/4" past the end of the slanted motorbox supporting piece. Then there is about another 1/2 - 3/4 inch then my AR6210 then the wing tube.
I would think that would be nose heavy.
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Old Jan 10, 2012, 07:10 AM
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kalmon's Avatar
United States, MI, Grand Traverse
Joined Oct 2008
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Quote:
Originally Posted by BOBBY1017 View Post
I would think that would be nose heavy.
I thought that is would be too, but the CG machine balanced it at 108, or so it said.... its not my CG machine and i never fingertip tested it as I trusted the machine. Maybe it was sticky or off, very nose heavy wouldn't do like I was describing, would it?
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Old Jan 10, 2012, 07:28 AM
TEAM HILLBILLY
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Groveport, OH...USA
Joined Nov 2010
10,179 Posts
i was extremely supprised to find how far back I had to move my battery to find neutral after i thought it was just "slightly" nose heavy...i had to slide it back almost 1 1/4 inches...and everybody that flies with the battery against the wingtube, I have no idea how you guys are doing that...you must have some spacers or something in the motor or a heavier motor...mine is a little heavier in the tail than most because i used 2x56 threaded rod and ball links on both ends of the servo linkages all the way around the plane but man....
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Old Jan 10, 2012, 08:13 AM
Honeybadger don't care...
Luv3d's Avatar
Orlando, FL
Joined May 2010
1,836 Posts
Quote:
Originally Posted by SteveTtoooo View Post
Don't need it. 3DHS planes are designed not to need differential.

SteveT
I agree that is how they are designed, but mine clearly walks left when I deflect full aileron to the right- so I'm trying to fix that. I have used a meter to measure the angles- and they are spot-on, so I'm perplexed. May just have to play with each a little.
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Old Jan 10, 2012, 08:18 AM
Honeybadger don't care...
Luv3d's Avatar
Orlando, FL
Joined May 2010
1,836 Posts
My 4000 mah 4S balances about 1/2" in front of the wing tube (batt weighs about 480g all in). I just picked up some 3300 mah 4S packs, and they balance much closer to the vertical supports on the batt tray- easily 2.5-3" in front of the wing tube. And my balance is almost perfectly neutral; I don't fly it slightly nose heavy. I run a Hyperion motor, 80A airboss ESC and no standoffs. I also have 2-56 threaded rod and ball links on both ends for all my servo linkages all around.
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Old Jan 10, 2012, 08:30 AM
I like the violent stuff!
Costa Mesa, CA
Joined Oct 2004
1,213 Posts
All my planes have a nose up attitude for landing. I put a few degrees of up "spoileron" to push the nose down for landing, put it on a switch to make it easy. I fly with a couple 3DHS Team pilots and they said forget the switch and learn to fly it out. It was intense at first but I'm getting the hang of it.
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Old Jan 10, 2012, 08:35 AM
Honeybadger don't care...
Luv3d's Avatar
Orlando, FL
Joined May 2010
1,836 Posts
I used a Throttle-ELEV mix, so when the throttle was very low or off, it mixed in 2% down elevator. Helped me keep the right attitude for landing. I'm a full scale pilot as well, and frankly am embarrassed at how bad my normal landings are with and R/C airplane. I can harrier land the snot out of anything- in almost any weather condition, but don't ask for a normal landing...it may be in another state, or hit LVC trying!

The only 2 planes I think I land well normally are a 46" Vyper and my 48" EF Extra EXP. All others have had CF landing gear replaced at least once if not twice...
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Old Jan 10, 2012, 08:39 AM
ADC Vinyl
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SoCal-Rancho Santa Marg.
Joined Mar 2007
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CG at the leading edge of the wing tube

finger test is the simplest way to do it. for what it's worth I've never cared for the machines and have seen instances with guys where they were way off for some reason.
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Old Jan 10, 2012, 08:46 AM
Sippin the Koolaid!
losifanatic's Avatar
United States, NC, Hertford
Joined Oct 2007
16,466 Posts
Quote:
Originally Posted by Fliprob17 View Post
CG at the leading edge of the wing tube

finger test is the simplest way to do it. for what it's worth I've never cared for the machines and have seen instances with guys where they were way off for some reason.
It's sad that a simple machine seems to mess up so many people. I know a lot of guys that couldn't get the cg machine to work for them??????
I don't use mine for setting up my initial cg. I only use mine to fine out where it ended up after I flew the plane and put it where I thought the plane flew the best. That way if I make repairs I will know exactly where to put my battery at to have the same cg as before.
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Old Jan 10, 2012, 08:47 AM
ADC Vinyl
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SoCal-Rancho Santa Marg.
Joined Mar 2007
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Quote:
Originally Posted by kalmon View Post
As it slows the tail continues to drop well below 3 point attitude and I'm having to use a little forward stick(not just released back, actual forward stick) to bring the nose down. All its gonna take is one light wind change or more likely me forgetting to put on low rates and it's gonna hit HARD nose first. My CG is at 108 which should be VERY conservative as I've heard of people maidening at 120. Any thoughts?
are you chopping the throttle at first, and/or controlling the decent/landing with the elevator? Land with the throttle, not the elevator. As soon as you chop the throttle on a neutrally balanced 3D plane, the tendency is for it to balloon up, making you force it back down. Keep the throttle at about 1/4 and gently force the nose down with the elevator. Then control the rate of decent with the throttle. It's perfectly normal to have to force the nose down just a little bit in a conventional landing.
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Old Jan 10, 2012, 08:56 AM
Registered User
United States, FL, Port Charlotte
Joined Jan 2008
927 Posts
Quote:
Originally Posted by Luv3d View Post
I used a Throttle-ELEV mix, so when the throttle was very low or off, it mixed in 2% down elevator. Helped me keep the right attitude for landing. I'm a full scale pilot as well, and frankly am embarrassed at how bad my normal landings are with and R/C airplane. I can harrier land the snot out of anything- in almost any weather condition, but don't ask for a normal landing...it may be in another state, or hit LVC trying!

The only 2 planes I think I land well normally are a 46" Vyper and my 48" EF Extra EXP. All others have had CF landing gear replaced at least once if not twice...
I used to use the same mix on all my 3DHS planes, but have since gotten the hang of just flying them in since I just didn't bother programming it in on a couple of the newer ones. It's not bad once you get the hang of it, however, it is a real handful when I go from one that has the mix to one that doesn't. It takes at least 2 tries to get the feel for it again. To make it even worse- we fly off a narrow street with my car and friends full sized truck parked on the side and us standing alongside them. Doesn't leave a bunch of room for landing and the curb gets awfully close if you are struggling with the landing at all. Yesterday, I had to come in with a bum aileron servo- would just stick in various positions, that was REAL fun to get down.
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Last edited by kwiktsi; Jan 10, 2012 at 09:07 AM.
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Old Jan 10, 2012, 09:09 AM
TEAM HILLBILLY
aronph's Avatar
Groveport, OH...USA
Joined Nov 2010
10,179 Posts
Quote:
Originally Posted by Fliprob17 View Post
CG at the leading edge of the wing tube

finger test is the simplest way to do it. for what it's worth I've never cared for the machines and have seen instances with guys where they were way off for some reason.
ben told me just BEHIND the wingtube..thats where mine is...and its just a touch ahead of neutral
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Old Jan 10, 2012, 09:14 AM
ADC Vinyl
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SoCal-Rancho Santa Marg.
Joined Mar 2007
5,229 Posts
leading edge of wingtube produces a very, very slight downward drop hands off inverted, that's how I like to set mine up. It's a good starting point, adjust from there to your liking.
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