Wing tip reinforcement

[SvingenB]

I’ve installed the full size wing tips using #4 screws and nutplates. The installation came out well however there is a LOT of unsupported fiber glass in the tips and I’m thinking I should probably reinforce it some way. I could spend a lot of time fitting foam and fiberglass supports or just install an extra set of wing ribs half way into the tips. The ribs would probably be easier and lighter than fiberglass reinforcement although I hate to see what the price is for an extra set of ribs ;(.

Anyway, wondering what others have done when using the full size, untrimmed wing tips.

I am wondering about long vs short tips. I asked Sonex about it, and the answer was start with the long and cut them later if you want to. This of course is not a very informative answer. Why do you want long instead of short?

Why would you support it with a rib? I would think any support would have to be extension of the spar.

[onex0127]

On my aircraft, I am starting with the long wingtip first. I purchased from Air Ward their wingtip removal kit which use's #6 screws. The kit was very easy to install and if I find I want a little more speed, I can always shorten the tips. As far as how strong is the long tip and does it need support. I can pick up the left or right side of the aircraft by the wing tip with no problem. Now I do not have the engine in yet, but it seams to be very strong. And the Sonex Onex seams to be doing OK.

Roy Taylor
127

[jcondon]

The reason I'm going with the full size tips is because Sonex says they are necessary to maintain Sport Pilot compliance for pilots weighing over 175 lbs. Since I weigh over 200 I figured the full size tips would be a good idea, especially if I get a picky DAR when I have the aircraft inspected. I have a private pilot certificate but the Sport Pilot stuff is new to me and I just didn't want to create any avoidable problems.

My reason for reinforcing the tip was not to add structural strength but to stabilize the wingtip surfaces. The upper and lower surfaces of the full size tip are quite large, thin and unsupported. My concern was the surfaces may tend to “oil can” or deform in flight and I was considering adding some type of internal support to the tips to help keep their airfoil shape in flight, not to provide additional structural strength. I probably wasn't clear about that in my post.

I know some RV builders have added foam and fiberglass to the inside of tips to help maintain shape and on my RV9, the kit included some aluminum bulkhead type supports I riveted inside the tips to help maintain shape. I thought adding another OneX wing rib halfway into the tip would be a fairly easy process and keep the airfoil shape in the tip without the top or bottom surfaces collapsing or oil canning. The weight of the extra rib would be minimal, probably less than any foam and fiberglass support I might fabricate. I know the rib would not be attached to the spar but the purpose of the rib is to just maintain the tip airfoil shape, not provide structural support.

Note: Just heard back from SoneX tech support and they do not feel any additional support is required for the full size tips. I'm still waiting to get a recommendation on hardware for making the tips "easily removeable" as stated on their web site. I also appreciate Mike Lauritsen's (Cleaveland Tool) knowledge and input regarding screw and rivet strength.

[radfordc]

The reason I'm going with the full size tips is because Sonex says they are necessary to maintain Sport Pilot compliance for pilots weighing over 175 lbs. Since I weigh over 200 I figured the full size tips would be a good idea, especially if I get a picky DAR when I have the aircraft inspected. I have a private pilot certificate but the Sport Pilot stuff is new to me and I just didn't want to create any avoidable problems.

Whether you want long wing tips or not is your business. The DAR's job is to determine if the aircraft meets airworthiness standards...not to determine if the pilot flying the plane is legal or not. Since the aircraft is not eligible for a "light sport" registration the length of the wing tips is irrelevant to the inspector. Once the aircraft is deemed airworthy it's your job to fly it "legally".

[jcondon]

That’s good information to know, I'm just not up to speed yet regarding Sport Pilot or Light Sport regulations.

I just want to be able to legally fly the airplane if I later choose not to renew my medical certificate. So, either long wing tips or losing 25+ pounds are my choices and long wing tips are probably the most realistic choice for me.

[fastj22]

That’s good information to know, I'm just not up to speed yet regarding Sport Pilot or Light Sport regulations.

I just want to be able to legally fly the airplane if I later choose not to renew my medical certificate. So, either long wing tips or losing 25+ pounds are my choices and long wing tips are probably the most realistic choice for me.

I've been following the development of the Onex since I sat in the prototype in 2011 at a builders clinic. The tips were not in the equation then. After flight testing at gross, Sonex offered the tips. I guess the stall speed was over light sport limits without them. Your DAR won't care. The only way you would get into a pickle is if you had an incident at gross with short wings and the FAA got up in your grill about it looking for a reason to violate you. Jeff Schultz told me that after his off airport landing, the FAA claimed his Jab3300 Sonex wasn't light sport compliant. He's a private pilot so it really didn't matter.
If I were building a Onex, I'd definitely look at that Ward kit to quickly switch out the tips.

[75sx]

How about both??? Dr. Jim.

[alien]

I have/had the same thoughts about these long unsupported wing tips. I wonder if one ever pulls 4, 5 or maybe 6 G's when a loop or spin doesn't work out the way we want, or at the Onex' Never Exceed Speed of over 180 kts, if those riveted tips would survive. So I cut them in half and hope for the best.

As for the comment made to stick to the plans, I wonder what can be wrong with the following:
the upper seatbelt attachment is done with 3 rivets. The bolt in the seatbelt bracket itself is of a huge size. I replaced two of those rivets by AN3 bolts (and so did many others).
The Onex is full of shortcomings left and right, at least the early plans, so changes area good idea in many instances and showed up many times in Revisions as a result of builder comments and modifications made.
Robert, Onex 81