Problem with horozontal stab and elevator set up
#1
Thread Starter
Join Date: Dec 2003
Location: christchurchnot aplicable, NEW ZEALAND
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
Problem with horozontal stab and elevator set up
Hi all, I have just set up my linkages to the elevators on my 28% WH extra LX and I have a problem with what seems to be the incidence of the stab as when all is in 100% neutral the trailing edge of the right elevator is about 3mm lower than the left, I have set up my linkages spot on and centered the servos, The elevators are not warped nor is the stab, I'm using a JR magic box so all is well with end points etc, the attached photo is not that clear but you can definitely see that there is a difference. On setting the trailing edge up level on both sides the leading edge of the elevators is then out the same as the trailing edge. My question is if I put an incidence meter on the stab 1/2s which one is correct, what is the actual stab incidence in relation to the wing incidence or the datum, This seems fairly easy fixed by plugging up the holes in the stab mounting plates, filling out the dowel hole and re packing and then re drilling the mounting plates at the correct incidence, harden all with thin ca and there should be no injustice to the airframes integrity. So it is the true stab incidence I require, I think? any help would be throughly welcome. Cheers
#2
My Feedback: (45)
Join Date: Jan 2004
Location: Columbia, SC
Posts: 792
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
Did you measure the incidence of your stabs as attached to the aircraft BEFORE you glued in the hinges? That is the easiest way to make sure your stabs are, in fact, zero degrees with reference to the wings (using a common reference for both, like the hatch surface).
Good luck.
Good luck.
#4
Thread Starter
Join Date: Dec 2003
Location: christchurchnot aplicable, NEW ZEALAND
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
Hi, Thanks for the advise FlyinTiger, I have contacted Tom. I will have to use a mates incidence meter as I don't own on but thought that this would not have been a problem, Like I said I do see it being a pretty easy fix all going well. From what you have posted it would seem that the design was for the wings and rear stab to be set on the same incidence. If I tape a straight line through the leading and trailing edges of the wings this will give me the same line the stab should be on only on a different height or plane on the rear of the fuzz.
Tom has asked me to contact him so that will be of great help as well, thanks again.
Cheers Tom I have sent you an e mail
Tom has asked me to contact him so that will be of great help as well, thanks again.
Cheers Tom I have sent you an e mail
#5
Senior Member
Join Date: Sep 2003
Location: Southeast Tennessee,
TN
Posts: 137
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
Hey Tom,
I see this same problem on my WH model 540 28%, it's off the 2nd batch. I just put it together late last year. This has drove me crazy cause it makes it impossible to get a perfect throw that is equal on both side. I have flow this plane and it flys good but could this be the issues I been having with my 3d elevators and harriers causing wing rock??? What would be a good fix?? Do I have two elevator halves that are for the same side? My plane was an all white plane when I got it. I'm open for suggestions....
I see this same problem on my WH model 540 28%, it's off the 2nd batch. I just put it together late last year. This has drove me crazy cause it makes it impossible to get a perfect throw that is equal on both side. I have flow this plane and it flys good but could this be the issues I been having with my 3d elevators and harriers causing wing rock??? What would be a good fix?? Do I have two elevator halves that are for the same side? My plane was an all white plane when I got it. I'm open for suggestions....
#6
Senior Member
My Feedback: (1)
RE: Problem with horozontal stab and elevator set up
The wing rock has nothing to do with the elevator situation. That's all lateral balance and getting to the correct angle of attack at the right power settings. The fix for the alignment condition is simply to use and incidence meter and determine which side is closer to a zero incidence relative to the hatch deck. Use the meter to adjust the other side to match by slightly elongating the holes in the stabilizer retention tabs. Then use a slightly larger washer to hold it all down. They never come loose, so no worries.
Getting back to the harrier thing, if a wing is rockin' it's because it's still developing lift. If it's developing lift it's because it's not fully stalled. It's not fully stalled because the angle of attack is not yet high enough to cause airflow separation over the forward portion of the wing. Bottom line, make sure it's balanced well laterally, pull the nose up higher, and use more power to hold it there.
Getting back to the harrier thing, if a wing is rockin' it's because it's still developing lift. If it's developing lift it's because it's not fully stalled. It's not fully stalled because the angle of attack is not yet high enough to cause airflow separation over the forward portion of the wing. Bottom line, make sure it's balanced well laterally, pull the nose up higher, and use more power to hold it there.
#7
Thread Starter
Join Date: Dec 2003
Location: christchurchnot aplicable, NEW ZEALAND
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
HI, ELONGATING THE HOLES IN THE RETENTION TABS IS ONLY PART OF IT; YOU ALSO HAVE TO DO THE SAME TO THE DOWL HOLE THAT SETS THE INCIDENCE BECAUSE THE STAB TUBE AND DOWEL SET THE INCIDENCE, THE TWO OF THEM, THE DOWEL AND THE STAB TUBE LOCK IT ALL IN. ONCE ADJUSTED YOU THEN HAVE TO FILL THE TOP OR BOTTOM OF THE DOWEL HOLE TO PREVENT THE STABS MOVING, HARDEN ALL WITH THIN CA AND RE MOUNT,
I HAVE TRIED IT ALL WITH AN INCIDENCE METER, NO LUCK THINGS JUST GET BETTER ON ONE SIDE AND WORSE ON THE OTHER.
I DON'T WANT TO GO INTO DETAIL HERE BUT TOM HAS KINDLY CONTACTED ME AND ALL WILL BE SORTED.
YOU ARE SPOT ON WITH THE WING ROCK EXPLANATION, I HAVE MANY PLANES THAT DO AND DO NOT ROCK AND THE MORE I FLY A HARRIER I FIND IT IS ME ON THE STICKS THAT CAN GET IT IN THE GROOVE OR NOT, LATERAL BALANCE IS A MUST WEATHER IT BE A 40 SIZE OR GIANT
I HAVE TRIED IT ALL WITH AN INCIDENCE METER, NO LUCK THINGS JUST GET BETTER ON ONE SIDE AND WORSE ON THE OTHER.
I DON'T WANT TO GO INTO DETAIL HERE BUT TOM HAS KINDLY CONTACTED ME AND ALL WILL BE SORTED.
YOU ARE SPOT ON WITH THE WING ROCK EXPLANATION, I HAVE MANY PLANES THAT DO AND DO NOT ROCK AND THE MORE I FLY A HARRIER I FIND IT IS ME ON THE STICKS THAT CAN GET IT IN THE GROOVE OR NOT, LATERAL BALANCE IS A MUST WEATHER IT BE A 40 SIZE OR GIANT
#8
Senior Member
Join Date: Sep 2003
Location: Southeast Tennessee,
TN
Posts: 137
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
Before anyone else chimes in about this question I've asked, I have investigated this as close as one person can and I'm not new to setting up a plane. I've set the elevator counter balance even with the leading edge on the elevator stab and set the incidence to 0 while checking the the other incidence meter that was at 0 on the wing then crisscross to the other elevator and made sure it was at 0. The wings and elevators are dead on 0, the problem is a warped elevator on one side. You can see it just like the guy in the post above and yes this does effect a 3D elevator, read anywhere and you will see that setting the servos to have the exact throw that is even on both sides will make the plane fly more stable in an elevator. This is why I asked is there a possiblity that I may have gotten two elevators halves made for one side?? Or is that out of the question due them being made the same and will work on either side??
#9
Senior Member
Join Date: May 2002
Location: Flower Mound (near Dallas),
TX
Posts: 6,189
Likes: 0
Received 2 Likes
on
2 Posts
RE: Problem with horozontal stab and elevator set up
That's what I thought they were doing at first, but I've tried swapping sides around and substituting other parts, the problems is simply that their build procedure somewhere along the line got sloppy. If you have elevators that don't match when the counterbalances are aligned, contact me and i'll get new ones sent out.
TF
TF
#10
Senior Member
My Feedback: (1)
RE: Problem with horozontal stab and elevator set up
Going off topic for a minute I'd like to provide some info that may or may not be useful regarding elevator timing between sides.
I've found that unless there are significant differences in the timing of the movement between elevator halves there will be little to zero impact on flight performance. I know there has been a lot of discussion on this subject, but real life practice with some very exotic and expensive flight platforms has illustrated the fallacy of slight differences in elevator timing having an effect on flight performance. I fly some unusual things for a living, and some of them have split elevons on each wing. There's often a slight movement lag between one surface and the one next to it, and that lag doesn't effect performance in any detectable manner to date. At well over 100k per unit combined with mission requirements, if it had a negative effect, it would most certainly be resolved before we flew again.
Pat
I've found that unless there are significant differences in the timing of the movement between elevator halves there will be little to zero impact on flight performance. I know there has been a lot of discussion on this subject, but real life practice with some very exotic and expensive flight platforms has illustrated the fallacy of slight differences in elevator timing having an effect on flight performance. I fly some unusual things for a living, and some of them have split elevons on each wing. There's often a slight movement lag between one surface and the one next to it, and that lag doesn't effect performance in any detectable manner to date. At well over 100k per unit combined with mission requirements, if it had a negative effect, it would most certainly be resolved before we flew again.
Pat
#11
Senior Member
My Feedback: (9)
Join Date: Dec 2001
Location: Thibodaux,
LA
Posts: 279
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
My 300Lx and my Extra 260 were both like that. I crashed the 300, but sure would love to get a replacement set for the 260! I think that may be contributing to my wing rock in upright and inverted harriers. I checked the incidence also and it is 0 also! Maybe I should call tom.
#14
Senior Member
Join Date: Sep 2003
Location: Southeast Tennessee,
TN
Posts: 137
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
Thanks Tom,
I'll be getting in touch also, I don't see any other fix then replacing the elevator. I've been real busy lately so I'll try to contact you when I get a break soon.
I'll be getting in touch also, I don't see any other fix then replacing the elevator. I've been real busy lately so I'll try to contact you when I get a break soon.
#15
Senior Member
My Feedback: (9)
Join Date: Dec 2001
Location: Thibodaux,
LA
Posts: 279
Likes: 0
Received 0 Likes
on
0 Posts
RE: Problem with horozontal stab and elevator set up
Hey guys, I called up Tom, took care of me with no issues! Still AWSOME customer service. Just letting you guys know. I will let you guys know what they look like when they arrive!