Hang Glider Strength

Thu, May 25 2017 05:29pm CDT 1
Allen Tighe
Allen Tighe
2 Posts
Hello.
New to the forum but I'm trying to get some information on sleeving the keel on a HG wing for use with a nano trike.
I have currently a older single surface 190 with stronger side wires and a very large piece of tube slipped the whole length of the keel except for a few cm where the nose plates meet and ending at the pull back ( tension cable) clip.
I have also seen some others with a very short section of tube just a bit longer than the hang block and still others with nothing at all.
Can someone please help to determine which is a better solution.
I'm hoping to be able to use my Moyes sonic 160 that I regularly fly as a HG for nano trike as well.
Thanks

Wed, May 31 2017 10:51am CDT 2
Lucian Bartosik
Lucian Bartosik
66 Posts
Allen,

What is your experience in aviation design, or structural engineering? Do you have a family you care about? If you have no experience it might be like fancing your hand at brain surgery on your child and see what some others may have done. You can not just start sleeving tubes if you have no idea how and why they have been designed to bend where they should, in order to make the wing fly properly. You have not given any thought to the stitching of the wing either, Im sure. There are far more stresses on the wing when flying all the added weight a trike and engine adds to it. On trike wings there is reinforced stitching on several sections of the wing, not found on a hang glider wing.

When sleeving I bet you had no idea there are stress relief cuts in the ends of the tubes to allow for flexing in those areas, otherwise the cutting effect a simple sliced off tube would have against the part of the tube that it is sleeving would begin to damage the inner tube. And do you know about deburring a tube and have the tools to do that when you have cut it? If you have no idea what I'm speaking of, then you have no business doing any work on your wing by yourself, unless you don't value your life and don't care about the sorrow you would forever leave with your family, should you come to a sudden end while flying, due to something you did with your aircraft.

I don't mean any of this in a nasty way, I just want you to wake up and realize that you are dealing with something that if done wrong, could possibly kill you and you should treat it that way. Have a certified company do the conversion who know what they are doing, despite what you have seen others do to their aircraft. They just may be accidents waiting to happen when the right chain of things go wrong. Most people value their lives and would rather have people who know what they are doing, do work on their aircraft. From your questions, it is evident that you don't have the required knowledge to do a safe job on your wing.
Wed, May 31 2017 08:44pm CDT 3
John Olson
John Olson
3 Posts
Allen, there's never been a shortage of blowhard know-it-alls who will happily tell you that you're crazy and gonna kill yourself, and yet we continue to experiment and fly in the face of them all. It sounds to this trikes that you are on the right track and will have a great experience. Go for it dude!
Wed, May 31 2017 10:01pm CDT 4
Lindsay Mannix
Lindsay Mannix
2 Posts
Allen,
most hang gliders are already strong enough but as you know the keel may need a bit more due to extra loads from twisting and landing that were not in its design origionally.

As far as being a aeronautical engineer goes the fact is that trikes in general are unusual in that with no gravity or positive g they are un controllable so there is that.

Nano trike ususlly means a 15 -25 hp light construction and low fuel usage ..it is what gives the most fun for dollar in my experience just be sure to look about and dont reinvent the wheel.. yahoo groups nanolight trikers is a good place for real information for us acknowledged test pilots .

There are a lot of peopel here who have spent more than a little on machines that dont really fly any better than a moyes sonic with a beffeed up lawwnmower engine ..with agarden chair for comfort.
They sure fly faster and carry with them some sofistication that most here will defend as necessary .

Alon with the speed come the need fo more area to be safe and a propper runway is esential for most of the machines reffered to here .
This may not be the the best palce to obtain the advice you seek .
Personally I have found that recreational flying is for fair weather days and fair weather machined that fly in circles and give the freedom of 3d motion to their owners in an unsofisticated way ...that said aviation will bite hard if you relax too much or fail in detail .

I have an array of machinhes but honestly my nano trike is the best on the right day ...on the wrong day they are all pretty useless for fun flying.
The other thing that you will find an abandunce of is opinion ..just make your aviation decisions carefully and know that its your opinion that matters.
Fri, Jun 2 2017 01:53am CDT 5
Allen Tighe
Allen Tighe
2 Posts
Thanks guys.

I understand the concern but I am not reinventing the wheel here.

My main concern is the twisting force on the keel during landing causing damage.

Anyway I will look at the Yahoo groups page but if anyone else has some helpful suggestions please let me know.


Mon, Jun 5 2017 02:12pm CDT 6
Doug Boyle
Doug Boyle
166 Posts
Seasoned blowhards (myself included) have seen this setup before; many times not ending well. Experiment slowly, learn quickly, and...completely!
Mon, Jun 5 2017 09:53pm CDT 7
Joe Hockman
Joe Hockman
40 Posts
I suppose some might consider me a blowhard although that is certainly not my view. I love to talk flying trikes and HGers and about the equipment so what follows are my opinions. Allen, first I would like to underscore and reinforce Lindsay's comments above. I happen to agree with almost every thing he said. Nano trikes are an absolute blast to fly. What I have discovered is that although there are a handful of TPS members with significant HGing and nano trike flying experience, the vast majority of those here do not come from that group. Almost no discussions occur here on the topic you brought up or most any other nano trike equipment aspect. So in general, this is not the best forum for getting the advice/opinions you seek. Lindsay is right, the nanolightTrikers forum on yahoo is probably the best place to get good advice. Mostly a membership that is passionate about light trike flying.
OK, I do have a bit of both science and engineering background so here are my opinions. Lucian is correct about some of the considerations but this is not rocket science and as long as you get good engineering advice, use good common sense, and apply it in any wing modifications then the likelihood of making a wing unsafe is reduced. On your Moyes Sonic 160, I think I would recommend a full length sleeve inside keel and that sleeve should slide in rather easily but with slight resistance. In other words, sleeved tube OD should only be a few thousandths less than the ID of original keel tube. Additionally, I would recommend a 2nd sleeve (inside first sleeve) only in the hang block area, but at least 6 to 8" on either end of where the HB could be located. Again ideally only a few thousandths less that ID of first sleeve. In contrast to what you described, I would prefer to have nose plate and haul back cable bolt hardware go though the sleeve, not just on original keel tube. Tubing wall thickness for sleeves need not exceed the wall thickness for original keel tube.
You definitely should file down or deburr end cuts on tubes used for sleeving. You can help to eliminate stress risers in HB area sleeve by making a couple longitudinal cuts 3/4 to 1" deep as if you were trying to cut tube end space as a pie with 4 pieces. 3 cuts like making 60deg pie wedges would be even better. Make sure you file down those cut edges. You want absolutely no sharp edges on sleeve tubing that may abraid inside original keel tube. A very small aluminum rivet through 3 tubes in HB area should secure internal sleeve. Best rivet placement is top or bottom surface of keel 1 - 2" in from end of shortest internal HB sleeve. Please note that these modifications will make your keel stiffer and add a bit of weight, and it may well affect handling/performance of your Sonic for free flying which is what you mentioned you wanted to do.
Sail and stitching that was used by Moyes was appropriate for that HG and specs given for free flying. Pay special attention to all aspects of the wing during preflights and this would include stitching. You probably should check battens against the template more frequently when using wing for nanotriking. You mentioned heavier duty side cables on your 190 but not on the 160 but one of the first modifications I would recommend for reinforcing a HG wing for nanotrike use is to bump up the gauge of the side wires. Oh and BTW if you are not experienced at swaging cables, this is not the place to practice. Make sure new cables are made by a wing manufacturer or another source of competent expertise. Lastly all the above is strictly my opinions and I am not a wing manufacturer so please consider that if you choose to follow any guidance above.
Tue, Jul 4 2017 12:25pm CDT 8
Tal Newhart
Tal Newhart
4 Posts
What Lucian said...
Wed, Jul 19 2017 02:24am CDT 9
Miracle Pie
Miracle Pie
7 Posts
Go here to consult without condemnation to many fellow pilots who've done exactly what you are contemplating:

https://groups.yahoo.com/neo/groups/NanolightTrikers/info

I fly a nanolight trike/hang glider with no additional keel reinforcement (the keel did come triple thick from the factory). Ten years, no deformation.

A few words of advice when adding a trike to a hang glider:

1) Hang glider placarded weight limits are not structural limits, but rather the maximum weight at which a glider's stall speed makes foot launching/landing practical. Placarded weights can be safely exceeded, within reason. The "tandem" (1/8") lower side wires are necessary.

2) The more weight on the wing, the farther forward your hang point should be. If you're at the maximum placarded weight, hang at the forwardmost foot launch position.

3) To compensate for the more rearward pilot position seated in a trike behind the basetube vs. hanging prone ahead of the basetube, many pilots simply turn their speedbar backwards, facing the rear. Otherwise you'll be leaning forward all the time to reach the basetube.

See you on nanolighttrikers.

Mon, Jul 24 2017 08:03am CDT 10
Gregg Ludwig
Gregg Ludwig
50 Posts
UL trikes have certainly evolved nicely over the years. Examples include the Ant by Aeros, Rev, NorthWing UL's, SkyCycle and UL's from Airborne. I purpose built UL wings are very light but at the same time much more robust than an HG wing. If you have ever drilled HG airframe tubing its like drilling through paper.

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