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RV14 wing tips

Tom Martin

Well Known Member
Typically I only install the wing tips after the wings are on the airplane and the flaps and ailerons have been rigged. This insures that the tips will match the ailerons.
I am curious to know how the tip alignment has worked out for those that have done the tips before installing the wings, as is called out in the plans?
 
Same question... I was thinking that if the aileron alignment jig were cleco'd in place the alignment of the tip is based on that jig.... so go for it! I'm planning a hinged installation.
 
I did a set some time ago on sawhorses and with the 14 aileron fixture in place it worked as well or better than a few other models done the plane
 
Typically I only install the wing tips after the wings are on the airplane and the flaps and ailerons have been rigged.

I'm about to put the wings on the airplane but I have already fitted, installed and trimmed the wing tips. With the rigging tool supplied with the wing kit, I am very confident that the wings can be rigged off the plane with very good alignment of the tips.

We'll see in a few weeks.
 
Wing tips misaligned

I installed wing tips as per the plan. It made sense following the plans and uniformity should have resulted. However it did not happen, when I finally mounted the wings to the fuselage and fitted flaps and ailerons I discovered the port wing tip did not align with the aileron as required and was out by about 3/16th of an inch. This was enough to make the plane fly out of balance. I had to cut the wing tip open and re-glass it to effect the repair.

In hindsight I think it would have been better to have waited to final assembly of the wing to ensure the wing tips aligned.

Food for thought.

Alan
 
You should be able to install the wingtips and use the jig and rig the ailerons with the flaps on the wing cradle. You will most likely want the ailerons and wingtips both aligned with the flaps with the flaps in reflex position, and that can be determined by just mounting the flaps while on the wing cradles.
I would not spend the time to completely rig them on the cradle though. Rig them to a close approximation but then do the final rigging with everything assembled on the plane. You will need to have the stick (elevator) neutral when you rig the ailerons for the final rigging because the ailerons will change position slightly with nose-up/down stick movement. But since everything should line up with the flaps (assuming you don't have twist in your flaps) you can rig them on the cradle.

One thing to check...with the flaps mounted on the wing in the cradle, look at your rivet lines against the top wing skin. You can tell then if you have twist in the flaps. The question then is, how bad is the twist? With a lot of twist, you won't necessarily want to rig your ailerons and wingtips to the flaps. Use the jig to see what the proper position should be. If you're all straight, you should have the jig in place and flaps in reflex and it'll all line up pretty well.
 
Thank you all for the input. My flaps and ailerons are very straight, no issue there. However there is no way to "see" if the wings themselves are perfectly straight.
A slight twist in one with the opposite in the other and it will show up with the wing tips maybe matching one wing but not both wing tips matching the ailerons/flaps at the same time. The wings should be perfect but if they are off even a small amount it will show if the tips are set using only the aileron jig. The jig just measures the aileron relative to the last rib of the wing and as such is an excellent place to start when doing the final rigging.

I think I will trial fit the wings in my shop and set the system before moving to the hangar.

Thanks again, I will report back in a few weeks and let you know how it works out.
 
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Careful with the jig...

I've just been through the wingtip fitting process in the past couple weeks. A while back I was told by Vans that the aileron jig in the early wing kits (I have s/n 140017) was wrong and has been corrected in later kits (don't know which s/n the change occurred in). Page 41-07 says:

"Step 6: With the control stick base in the "fully neutral" position, verify that the ailerons are approximately 1/16 [1.6 mm] above the trail position with respect to the wingtip trailing edges. NOTE: Newer revisions of the W-00026 Alignment Template will have a reflex ID hole as shown on Page 23-10, Figure 2. If the template does not have the reflex ID hole, use shims to rig the trailing edge of the Aileron to protrude approximately 1/16 [1.6 mm] to ABOVE the trailing edge of the template. The Ailerons must be in this slightly reflexed position to compensate for aerodynamic loads during flight."

It was not clear to me how to identify the "reflex ID hole" but I sent a picture of my template and was told I had the older version and I should therefore rig the TE of the aileron 1/16" above the template. So, with both wings in the cradle that's how I rigged the ailerons (by adjusting the pushrods such that the bellcrank and wing root torque tubes were all in the specified neutral positions).

After making all the adjustments I decided to install the flaps just to see how everything looked and it became obvious that the aileron alignment could not possibly be correct...the TE of the ailerons was about 3/16 to 1/4" higher than the flap TE, and the flaps cannot go any higher (the LE of the flaps hits the rear spar in the fully reflexed position). I started thinking that the instructions must be wrong and actually the TE of the aileron should be rigged 1/16" below the template as this would provide better alignment with the flaps. So I emailed Vans to ask and received this response:

"This is because of the new tool to align the 14 ailerons, which takes no account of the flap position, and makes no allowance for any variations in the flaps/ailerons. See attached RV-10 section 23-9 that achieved the same task with no tool, simply by aligning the aileron with the flap. Probably a simpler way to go, if you want the ailerons and flaps to align. Either way, a 1/8 up/down is no problem."

So, I tossed the template in the scrap bin and went about alignment in the following manner:

1) First I used my digital level to verify that with both flaps in the full up position, they both have the same relative angle between the top surface of the flap and the top surface of the wing (as measured along the straight section of the ribs that extends a dozen inches forward of the rear spar). I recall this being about 3 deg reflex angle, but the important part is that they are identical on both wings. One flap was about 0.2 deg different from the other, so I placed a shim between the rear spar and flap LE to make them the same.

2) Then I adjusted both ailerons (bellcrank-to-aileron pushrod) to align the aileron TE with the flap TE. I double checked the aileron-to-wing rib angles just like I did for the flaps to verify they are identical on both wings.

3) I then fit the wingtips with the wingtip TE in alignment with the aileron TE. On the left wing the tip aligned perfectly. The alignment of the right tip wasn't quite correct, so I fixed it by cutting the inboard half of the wingtip with my dremel tool and re-bonded it with a couple pieces of fiberglass inserted to fill in the gap created by the cut. Clamped the TE between two pieces of alum angle that were also clamped to the aileron to hold everything in alignment until it dried.

I'm pretty confident my TE surfaces are now well aligned with the basic wing structure. Hopefully the wing incidence will come out equal on both wings using the plans procedure for drilling the rear spar holes (I would have preferred the approach used on earlier RVs where you install the wings, carefully align everything, and then drill the rear spar attach holes to the fuselage with everything assembled as I have a higher degree of confidence in getting both wings exactly the same with that process).
 
Mark,

That's confusing indeed. Almost like you're getting too much info, eh? :)

It sounds like in the end you'll have your flaps, ailerons, and wingtips aligned well. On my RV-10 I too had to cut the back of the wingtip and split them and re-glass them to get them to match up just right. On the RV-14 I didn't but I suspect some people may still run into that situation. I did also trim my wingtip trailing edges a bit so that they didn't stick out too far past the ailerons...it just looks ugly that way. So that caused me to file a bit to thin out the aft edge of the wingtip so that it matched up ok. That left a couple of places that needed voids filled, so I did that too.

All in all, it went well, and it flies fine. I think most people should be able to navigate this step without too much trouble.

To Tom's point about wanting to ensure the wing comes out straight...I understand the concern, but many RV-10 and RV-14 wings have been built without any jigs, and I haven't heard of anyone having any measurable twist in their wings. I'm sure there is the possibility for some slight variation, but in following RV-10 builds for over 11 years now I haven't heard of any issues. So I'd be surprised if you find anything significant. Good luck and hopefully you'll be well satisfied when you see how it came out.
 
Mark
Thank you for your excellent post. This is exactly what I was looking for and I will definitely wait until the wings are on the plane before set the wing tips. Your method is exactly the one I have followed on my other aircraft but I wondered it the RV14 might be different.
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. At the time I just put that down to the fact that I know how hard they pushed to get the airplane flight ready for the show. Your post confirmed how I think it should go. We will see how this one works out!!
Splitting the trailing edge of at least one of the wing tips has been done on all the planes I have worked on. The wing tips of the RV10/14 are much better then the preceding ones but the 10 I worked on still needed a bit of tweaking on one tip.
 
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......


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.
 
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.
 
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.

20qflfa.jpg


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.

rif4oi.jpg
 
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.
 
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.
 
Slow learner on this...

I just got my flaps, ailerons, and unmodified wingtips installed per the plans. Like others I could only get 8-deg on my flaps versus the depicted 7. But they are symmetrical within 0.3 degrees at the fully up position. I'm calling that good. With the control stick in the fully neutral position both aileron TE's are above the flap TE and wingtip TE by about 3/32, maybe a tad more, but they are spot on symmetrical.

I have not measured exactly but the eyeball says the flap and wingtip TE's are very close to matched. Probably not off enough to do any adjustments (I hope.)

I'm going to do some more measuring but this seems to match what others on this thread were trying to achieve...and what Vans says is the desired configuration. Agree, disagree??

If this is all correct Vans gets all the credit...I just followed the instructions.
 
I just got my flaps, ailerons, and unmodified wingtips installed per the plans. Like others I could only get 8-deg on my flaps versus the depicted 7. But they are symmetrical within 0.3 degrees at the fully up position. I'm calling that good. With the control stick in the fully neutral position both aileron TE's are above the flap TE and wingtip TE by about 3/32, maybe a tad more, but they are spot on symmetrical.

I have not measured exactly but the eyeball says the flap and wingtip TE's are very close to matched. Probably not off enough to do any adjustments (I hope.)

I'm going to do some more measuring but this seems to match what others on this thread were trying to achieve...and what Vans says is the desired configuration. Agree, disagree??

If this is all correct Vans gets all the credit...I just followed the instructions.
Not quit at this step but hopefully will be very soon and I was wondering if the 7 degree for the flap is down from the longeron or up from the longeron. Judging from the drawing is hard to tell but I am guessing that it is down.
 
You got it...it's down. At this point (reflex) your flap leading edge will be resting against the rear wing spar. Can't go up any more.
 
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You should be able to install the wingtips and use the jig and rig the ailerons with the flaps on the wing cradle. You will most likely want the ailerons and wingtips both aligned with the flaps with the flaps in reflex position, and that can be determined by just mounting the flaps while on the wing cradles.
I would not spend the time to completely rig them on the cradle though. Rig them to a close approximation but then do the final rigging with everything assembled on the plane. You will need to have the stick (elevator) neutral when you rig the ailerons for the final rigging because the ailerons will change position slightly with nose-up/down stick movement. But since everything should line up with the flaps (assuming you don't have twist in your flaps) you can rig them on the cradle.

One thing to check...with the flaps mounted on the wing in the cradle, look at your rivet lines against the top wing skin. You can tell then if you have twist in the flaps. The question then is, how bad is the twist? With a lot of twist, you won't necessarily want to rig your ailerons and wingtips to the flaps. Use the jig to see what the proper position should be. If you're all straight, you should have the jig in place and flaps in reflex and it'll all line up pretty well.

+1

This is what I did on the 10 wings (same a 14). The cruise "in trail" baseline is the flap fully pressed against the rear spar. Be sure there is no binding and the flap is hitting the spar. Then use a spring clamp to hold the aileron parallel to the flap and install the wingtips to match the aileron. Rigging comes later. Here you are just installing the wingtips in the designed wing In trail (actually -3* from) position. rigging with the bell crank is not relevant for this step and I would not use the aileron alignment tool for this step. That said, it is a logical next step to rig the bellcrank while you have everything in position and gravity is helping to hold the flap against the spar, as well has holding the bellcrank against the alignment jig.

It's actually easier on wing stand, as gravity holds the flap against the spar.

Larry
 
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