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Old Jun 28, 2011, 09:00 AM
KingtechUSA
gunradd's Avatar
Tampa FL
Joined Apr 2009
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Fab not sure on that set up but make sure you use the closest possible hole on the servo arm to the servo center. That will give you better mechanical advantage.

Does the instructions call out to flat spot the shaft for the set screw? Post some pics. I bet Chris could help you allot more then.
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Old Jun 28, 2011, 09:09 AM
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thanks gun! yeah i am using the closest hole to the centre but on the elev. rod there are no flat spots...
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Old Jun 28, 2011, 10:41 AM
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JetMang's Avatar
San Diego, California, United States
Joined Feb 2002
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No need for flats. The rods are brass, so when you tighten it down, the screw will create an indentation which should lock it in place. When you have it all powered on, is there any kind of play around neutral when you wiggle the trailing edge? Typically, having the pushrod closer to the center of the servo will induce slop around neutral...I typically do the opposite and move the pushrod further out from the center. Try moving the pushrod out to see if it improves. Otherwise, how significant of a mismatch are we talking about quantifiably? what servos are you using and how many cells to the rx?


Chris
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Old Jun 28, 2011, 06:09 PM
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Yes there is a play around neutral of more or less 1cm from the leading edge. I tried the push rods in all the positions of the servo arm, the better spot is half the way however when i move the stick they don't get to the center of 1 or 2cm i need to play with the stick to eventually get it centered! Rx is the standard futaba 4.6volt rx ...
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Old Jun 29, 2011, 11:29 AM
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1cm of play is almost 1/2"! There's something wrong. I wonder if your stabs are defective. In one instance, I received a pair of stabs where the pivots were insufficiently glued and the stab itself had play in it where it would rotate around the pivot. I wonder if thats what's happening. You could check that by removing a stab, holding the pivot with a pair of pliers and seeing if it has any play. If so, then time to request a replacement set of stabs. That would also cause the double centering.

On the rx pack, if you're running any 2.4 ghz radio other than airtronics, then I highly recommend a 6v pack. The min voltage on those systems is in the 3.5v range (min voltage on airtronics is under 2v) so a 4.8v pack doesn't give a huge margin. Also, the extra speed and torque you get at the servos from running 6v doesn't hurt either. lately, I've been using the hyperion life packs and like them a lot. A 6v 2100 mah pack only weighs 3 oz and some change.


Chris
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Old Jun 29, 2011, 01:02 PM
Pursuit of Happiness
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Brentwood, California
Joined Jul 2007
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Quote:
Yes there is a play around neutral of more or less 1cm from the leading edge. I tried the push rods in all the positions of the servo arm, the better spot is half the way however when i move the stick they don't get to the center of 1 or 2cm i need to play with the stick to eventually get it centered! Rx is the standard futaba 4.6volt rx ...
My friend Rudy has a JHH A-7 ARF that I've been trying to help him get ready to fly for along time. We were ready to go then I checked the plane over last week and also found the stabs have a huge amount of slop... also about a 1/2 inch.
He wanted to just fly it and I said no way!

I know he contacted JHH and is going to get a new set of stabs.... I have to say we are really disappointed in the over all quality of this kit. It was an ARF, it just seem like the components are all from the stone age. Nothing compared to Tam Jets, Yellow Aircraft or even Jet Legend for that matter.

I'm not trying to be harsh I really like Chris and Larry, but it seems to me these kits need updating.

The whole back of the plane seem weak, no bearing blocks for the stabs. just rides on a ply plate with a bushing. I know it all works. But it could all be so much better

My friend is just disgusted he wanted to just give me the plane ready to fly for $500 bucks to get rid of it, he spent $2000 grand for it. I told him we can make it right and get it air born... he wants to give up on EDF altogether because of this plane. It had a ton of issues, some from shipping, some from the builder and some from JHH. So he has had a really tough time with this plane.

I hope I can help him sort it all out, but the slop is the main problem right now
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Old Jun 29, 2011, 03:39 PM
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Ron,

I'm sorry to hear of the troubles. I don't know any specifics in this case, but we are always here to help as best as we possibly can. If there's anything I can do personally to help, please pm me.

regarding the kit, I'm sure you're aware of the history a bit. If not, i can explain in a pm.


Chris
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Old Jun 29, 2011, 03:58 PM
Dream Build Fly Scale
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Philadelphia, PA
Joined Oct 2004
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Ron, you gave your friend good advice to show resistance and hold off flying the model. Chris and Larry were very accesible during my build and I have every bit of confidence they can help you out to get things sorted out. Good people and avid modellers that are interested in your success more than they are in just selling another kit.
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Old Jun 29, 2011, 05:43 PM
Pursuit of Happiness
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Brentwood, California
Joined Jul 2007
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Thanks Chris,
I know he had talked to your dad and is getting new stabs... then we are going to redo the whole setup back there. New servos, metal gear, new linkages... the works. Then it should be ready to go

Your totally right Sean, I've meet Chris and Larry in person and they are both super nice guys. I guess I was just vent a bit for my bud.

Where going to get it workout out and fly this puppy, the finish on the plane looks good... and I'm sure once sorted it will be a good flyer.

keep you posted on how it works out, if we have issues I'll drop you a PM Chris and thanks for the offer to help out.
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Old Jun 29, 2011, 07:35 PM
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San Diego
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Well I know that the one I picked up has not had any of these issues and a buddy of mine has had 2 of them (one EDF one Glow) and he has had great success with them. His EDF one ways 15lbs and is still managable in the air. Ron I am sure it can get worked out and your buddy just needs to be patient and do it right, issues come up and you just have to deal with them. I just ordered up a bunch of missing parts for mine (got it second hand half built) and Cindy and Larry have been really helpfull in getting me what I need!
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Old Jun 29, 2011, 10:03 PM
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ok change the servo arms and the clevises and managed to reduce the play of the elevators to about 1/3 1/4 inch and if i am really smooth on the radio i can almost get them centered however still not happy! if they don't get centered properly in the air it will be a disaster!! The stab and the rods seems ok! tried with the pliers and seemed fine...i don't know what to think...if i push the push rods with my hands seems there is no play and swing ok...Isn't that silly how something so stupid ca really ruin your day?
I am at my wit's end...
Thanks every one!
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Old Jun 29, 2011, 10:49 PM
Not Funny......
Mike Warren's Avatar
United States, CO, Redstone
Joined Dec 2010
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It's either the servo end or the stab end of the system........
Grab the pushrods linkage, so as to prevent any pushrods movement, then gently put pressure on the stab.........if it doesn't move then the servo end of the setup is your problem.
Same test the other way to see if the servo is ruled out.

I have an absolutely solid no slop stab setup (maybe +/- 1/2mm at the leading edge) on my JHI A-7 ARF and it was done just as JHI originally designed for EDF.

Odd that you reference distortion of the fuselage at the servo area when you operate the stabs. That would surely seem to me that there is significant binding occurring somewhere.
-Mike
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Old Jun 29, 2011, 11:13 PM
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San Diego
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Out of curiosity what servos are you using and what voltage are then running on?
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Old Jun 30, 2011, 06:29 AM
Dream Build Fly Scale
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Philadelphia, PA
Joined Oct 2004
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Seems baffling...can you post some pics? Could your rods themselves be flexing?
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Old Jun 30, 2011, 09:30 AM
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Joined Jun 2009
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Took the entire tail section apart. the stabs are good, no play and on their brass rod there is the dent of the screw( that means that there is grip between the rods and the collar) I pulled the push rods with no stab by hand and there is a tiny play...
My servos are BMS 9.1kg .15sec with 4.8volts I used them before and worked flawless!
May be are the push rods...can't think about anything else...
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