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Dec 01, 2012, 11:36 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
Slit the hingeline with a razor blade from the top all the way to the kevlar, then use a piece of double sided sandpaper (two pieces 3m77'd together) and draw this through the slit repeatedly while pulling upward on the flapperon. This makes a progressively wider V on the top, and you can simply stop when the control is deflected upward about half an inch (more than enough travel.)

The V is very clean. This is the same way I do my tails, which obviously are also solid core.
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Dec 02, 2012, 01:21 AM
Registered User
Brilliant! I'll try this on my next tail set.
Dec 02, 2012, 08:18 AM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
Gentle pressure on the flapperon until the paper moves fairly freely, and round the edges of the paper so it doesn't bunch or tear. Expect to really severely screw up the first one, then it becomes easy.

With tails, you will tend to do more damage with the hand holding the tails than the one sanding the groove. With wings, put something soft on the bench so you have a place to rest the opposite wing. You don't want it randomly flopping around the shop. Trim your fingernails Go slowly at first. Don't hold the surface against your body or you'll end up creasing something. Please don't ask why I can rattle off so many things NOT to do.
Dec 02, 2012, 03:19 PM
F3B and F3K
RetoF3X's Avatar
Originally Posted by tom43004
Some construction pictures. If you have any questions, just ask. Kevin does this look better to you?

(btw these pics were from a 40psi XPS wing)
Could you alternatively put a carbon (or glass) sock around the 3 mm foam cutout? Then you could later slot the carbon sock from the top (hinge in the middle)?

Maybe for power launchers.

Looking great!

Dec 02, 2012, 03:51 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
I tried that Reto. The added material makes the hinge very difficult to break loose. The shrinkage of the epoxy during cure also makes a very small (but cosmetically noticeable) indentation at the carbon as well. Additionally it's more expensive and black. I have also wrapped the foam block in glass on one wing. Cheaper, seemingly just as stiff, cosmetically not so bad because the black isn't there... but also a pain to hinge.

Wait until you get your hands on one of these wings. The double facing is very resistant to delamination at the hinge, and they're very very very stiff.

BTW I am laying up a lighter weight wing today. We'll see where the weight ends up when I pull it out tomorrow. Man that sounds good. Starting a layup in the afternoon on Sunday and pulling a finished production wing tomorrow
Dec 02, 2012, 05:53 PM
Registered User
Tom. I will happily accept a super fr3ak wing for testing and let reto launch it for strength testing. We fly in the cold.

Just saying.

Dec 02, 2012, 07:40 PM
hass-alfed and bass-ackwards
carlsoti's Avatar
Originally Posted by tom43004
BTW I am laying up a lighter weight wing today.
Awww maaan. I though I was witnessing the birth of DLDS.

Seriously though, the pics look really great. I can't wait to see one up close.
Dec 02, 2012, 10:09 PM
a.k.a. Matt Nelson
MattN's Avatar
Originally Posted by carlsoti
Awww maaan. I though I was witnessing the birth of DLDS.
too late - check out 2:10...

Fun at Bird Springs Pass and Weldon - International DS Week 06 April 2012 (5 min 50 sec)
Dec 02, 2012, 10:23 PM
Registered User
Thanks for all the information on the hingeline. I'm glad I asked about the current process; I learned something (or quite a few things) and got some additional info on your thinking for the hinging facing methods. It sounds like it was helpful for some others too.

Looking forward to the light layup, and curious what types of changes you implement for that.

To the above-- I've tried DS'ing a Helios on a small dam. The wing was plenty strong, but the weak shear layer meant I maxed at about 5 circuits. I asked about it over in the DS forums and it sounds like quite a few people have done it with a DLG, though many prefer a "plank" in this application for several reasons...
Dec 02, 2012, 11:12 PM
Registered User
I managed to DS my way out of a hole at a contest once. You never know... Any source of lift, any way that makes it work!

Dec 03, 2012, 10:43 AM
Time for me to Fly...
Mr. Wiz's Avatar
I wish I could understand how to DS. I'd like to give it a try on a tree row just to see if I could do it.
Dec 03, 2012, 11:39 AM
Registered User
DS is all about airspeed. It is a method of soaring which uses a wind speed gradient or better, some wind shear, as a method of increasing airspeed. The increase in airspeed can be used to maintain altitude.

When one is out throwing a DLG in strong wind, and throws at say a 60 degree angle, notice how the plane just keeps on going and climbing? The wind, due to boundary layer constraints, is at a speed of zero right at the ground. At altitude, it is at some (pretend here) steady speed. As one gains height above ground, the speed increases.

A plane thrown into this wind starts with a speed which is the speed of the throw plus the speed of the wind at shoulder height. As the plane rises, of course it loses energy, exchanging the kinetic energy (referenced to airspeed) for potential energy (altitude). Some is just flat out lost due to drag of course. But mostly we are converting speed to altitude.

In the wind situation though, as the plane rises, it encounters air moving faster relative to the air the plane just left. So the plane gets a free boost in airspeed. This is essentially free energy! That's why the plane keeps on climbing so nicely when not thrown vertical in a wind.

That's just using a windspeed gradient. Now picture instead that the wind is moving at a slow speed down low, a fast speed up high, and the transition occurs over a small change in altitude. As a plane passes up through such a wind shear, it gets a sudden boost of airspeed. This can be converted to altitude readily enough. But lets assume that instead one wants to do something different.

Now the plane is flying fast in that upper air. Where can it find some more air at a different speed - to gain more airspeed?

Right below it, actually! That air it left a moment ago. If the plane turns around, and then passes DOWN into that lower air, well now that air mass gives a boost in airspeed!

Of course, in that lower air, now one can turn around and then pass up into that upper air and do it again! This is dynamic soaring.

The back side of a sharp mountain ridge has air that is 'relatively' static. The front side has high wind. The transition between these air masses can have a considerable wind speed difference. That wind shear can be used to dynamically soar to extremely high speeds - or rip the wings off, depending.

But there are numerous other ways one can use a wind gradient or shear to gain a little boost.

Consider wind blowing at a treeline, but at an angle. At the treeline one can gain a bit of lift of course. But can one do better? Yes, by paying attention to the windspeed gradient.

When air hits a treeline, some air goes over, and some goes through the trees. What goes through the trees compresses (it can't really, SO), and rises up out of the trees. The air slows down!

So we have faster air in front of the trees, and slower air above the trees. When the air approaches the trees at an angle, now we have a useful windspeed gradient.

When one is using a treeline and the wind isn't fast enough, sooner or later one has to turn. The question then is which direction of turn, and where, is optimal?

You want to maximize airspeed! When going in front of the trees, turn towards the wind. When passing back over the trees, turn away from the wind. Turning in this way uses the windspeed gradient for a slight boost in airspeed - convertable to altitude or at least to helping maintain altitude. That is a minor bit of dynamic soaring.

Test it - the direction one turns in marginal situations with treeline lift at an angle, can determine whether you can stay up or whether you can't.

BTW, that's another reason to learn to turn equally in each direction. Sometimes there really IS a preferred direction.

There are other DS scenarios. Just keep an eye out for windspeed gradients and think about how to use them to gain airspeed.

Dec 03, 2012, 12:44 PM
Time for me to Fly...
Mr. Wiz's Avatar
Thanks, Gerald. I'm going to go back and re-read hoping to retain enough to use that info next time I'm flying in the wind. I get all sorts of wind and tree line situations so I'm sure at some point I can make some use of that info.

Dec 11, 2012, 01:08 AM
Full disclosure, not sponsored
Stupid question time. And remember, there are no stupid questions, just stupid people!

So I ordered a freaky horizontal from Tom for my Stobel. Looks killer great Tom!!!

My other Stobel horiz is 8.2 grams or 126 some other g on my scale.
The freaky horiz is 6.8 grams or 104 some other g on my scale.

Maybe the other g means grains???

Anyways, I refered to this picture as well as my 4 other DLG's which have the horiz hinge line on the top. This pic from a previous freak post also confirmed this was correct. But man, I swear the airfoil is upside down. If I put it on a piece of glass the "Top" the side with the hinge is almost flat and wont rock on the glass. Flip it over and she rocks back and forth.

Soooooo, what gives?

Is that a correct mount?

Bad news is I countersunk the screws in the CF patch side but I think that will end up wrong. It would not make sense that the countersink would be in the hard points vs the CF patch area? Or does it, Or does the freak in freaky mean the airfoil is inverted? HELP.

Also, the horiz sits forward about 1/2" of where the stock horiz does based upon the hard points.

Maybe this is a Polaris horiz I got, that goes under boom? Wait, would that make sense???
Last edited by JONBOYLEMON; Dec 11, 2012 at 01:23 AM.
Dec 11, 2012, 01:21 AM
Full disclosure, not sponsored
PS, its been several very late nights of building & resurrecting a Stobel that was on fire a few months ago and has been slowly nursed back to health after some serious nose work.

I will see if the horiz looks messed up in the morning after some rest.

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