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  #11  
Old 05-01-2017, 09:50 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,056
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Proper installation of wing tips on any RV requires primarily one thing.... having the aileron fixed into the neutral position so the the training edge of the wing tip can be aligned vertically and in roll to it.

How this is done doesn't matter.

Using the template supplied in the RV-14 wing kit works well (it was used to install the tips on the tail dragger prototype).

Installation errors are possible with any method if the aileron was not confirmed to be in the nominal neutral position or if it moved during the install process.

Mis-alignment of the tip trailing edge after final assembly of the aircraft and installation of the flaps and ailerons is likely caused by the positions of the ailerons being compromised to account for twist in the flaps, ailerons, or both. Not the best way to build an airplane but there seems to be a large tolerance of variation without it have much effect on the flying qualities other than probably a tiny bit more drag.

Point being..... if installing the tips after flap and aileron rigging produces a better result then there are some construction errors that are being compensated for, rather than fixing the actual problem......


Quote:
Originally Posted by Tom Martin View Post
When I checked out the prototype RV14 at AirVenture the first time it was there, I looked at the alignment of the ailerons, flaps etc and was told at the time that this plane was different, that things would not line up.
Without specifics I can't comment on what you saw, but a lot of experimenting with aileron rigging has been done since then.
It was discovered that because of the reflex position of the ailerons on the RV-14 coupled with just a bit of elasticity in the control system, the ailerons actually deflect downward very slightly in high speed flight so once the airplane was fully built the ailerons were rigged so that on the ground they will look about 3/32nds" high on each side relative to the wing tips. In flight they are exactly in trail.
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Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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  #12  
Old 05-11-2017, 07:20 AM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,306
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I have the wings temporarily on the aircraft using hardware bolts rather then the final close tolerance bolts.
I set the flaps in the full up, reflux, position as per the instructions.
The wing to stick push rods lengths were set as per plans, as were the flap push rods.
With the stick in neutral, (elevators in the neutral position) the right aileron lined up perfectly with the flaps. The left aileron was trailing edge low by less then 1/8". This is pretty darn good for having followed the plans and using the aileron jig to set the wing push tubes. Minor adjustments from here would have made the tips line up if I had placed them on the wings in the jig.
I have not yet installed the tips, that is the next job but so far things are working out really well. Any twist in either of the flaps would mean that the alignment with tips already installed on the wings would make it difficult to line things up.
My suggestion would be to wait until the wings are mounted not the aircraft before final tip fitting. There really is no reason to do the tips in the jigs, it is no easier then doing them in the jig then on the assembled aircraft.
These are the closest aligning control surfaces, from an initial fitting, that I have yet encountered; Awesome.
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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger flying #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #13  
Old 05-20-2017, 06:15 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,306
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I used the hinge method of attaching the wing tips. Quite a bit more work but looks really nice. Not sure if I would really recommend it as you would have to be taking your wing tips off quite a few times to make up for the extra initial time. There is likely a small weight penalty with hinges but this is offset by not having to deal with the small #6 screws, which can be difficult at times.
When I got the tips in their permanent position both tips were about 1/8" higher on the outside then next to the aileron. Ok but not a nice sight line when the surfaces are lined up. The irony about surface alignment on the RV14 is that they are only going to line up perfectly when the elevators are in the neutral position. Thus when you have the stick tied back on the ramp at AirVenture it will appear that you messed up on the rigging. This may be what I saw on the demonstrator.
Nothing wrong with the system it is just a quirk of the controls on the 14, and also, I believe, on the 10.
Anyways, both tips were also about 1/4" long so first off I trimmed them for length and then I slit the end.



The next step is to rough up the inside trailing edge with sand paper and install the tip back on the wing. Spread the trailing edge and insert a generous amount of flox and epoxy, a stiff mix. Then using two 6' angles I clamp them to the tips, ailerons and the outside bit of the flaps. This is done on both sides of the aircraft at the same time to insure that everything lines up.
The next day the tips are removed and an added 3" wide strip of glass and resin is inserted in the aft end of the wing tip, over the flox.

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Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger flying #153

Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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  #14  
Old 05-20-2017, 06:43 PM
MED MED is offline
 
Join Date: Jul 2015
Location: Aiken, SC
Posts: 167
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I like the idea of the angles to align the tip trailing edges with the ailerons, but their use seems to be in conflict with Scott's comment that the ailerons will be 3/32" high compared with the tips. Not sure how to achieve that.
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  #15  
Old 05-20-2017, 07:02 PM
czechsix's Avatar
czechsix czechsix is offline
 
Join Date: Mar 2006
Location: Spring Hill, KS
Posts: 254
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Quote:
Originally Posted by MED View Post
I like the idea of the angles to align the tip trailing edges with the ailerons, but their use seems to be in conflict with Scott's comment that the ailerons will be 3/32" high compared with the tips. Not sure how to achieve that.
My take is that you align the flaps, ailerons, and wingtips during rigging/fitting.
Then if the ailerons are deflected slightly TE low in flight, you just shorten each aileron pushrod by a turn or two.

Put another way, you really want the flaps and wingtips aligned well...the ailerons are easy to adjust slightly up or down later on as needed to be aligned with the flaps/wingtips in flight.
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Mark Navratil
Spring Hill, KS
RV-8A N2D #80583 - built/flew/sold
RV-14A #140017 - wings complete, empacone in progress...
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