It's my first time! LEG 1D Build & fly - RC Groups
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Oct 26, 2007, 05:09 AM
If it ain't broke...break it!
Hangtight's Avatar
Build Log

It's my first time! LEG 1D Build & fly

After my good intentions of putting my LEG 1D kit aside until I'd got a load of jobs round the house sorted, I couldn't resist getting the bits out and taking a look. To cut a long story short, I got a bit carried away and after a couple of hours of belt sander abuse, and a few more of glueing and hacking, I now have a shaped fuse and a wing with spar and sub TE installed

This morning I sanded the sub TE to match the foil and then offered up the supplied aileron stock. Hmm, the aileron stock is thicker than my nicely sanded sub TE. So here's the question. Do I sand the ailerons down to the same thickness as the sub TE and leave myself with an almost knife edge TE, our live with the step, which is about 1mm? The wing will have 2 servos instead of the torque rods, and the ailerons will be top hinged.

Apologies for the poor pics. The kids borrowed the camera batteries for the Game Boy
Last edited by Hangtight; Mar 04, 2008 at 11:15 AM.
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Oct 26, 2007, 05:12 AM
satinet's Avatar

I think the aileron stock has been thicker than the sub t/e on every kit i've had so far - this is perfectly normal. Don't leave a step (aka drag) - sand the ailerons to match the profile of the wing.

A thin T/E on your ailerons is a good thing. However, too thin and they become very weak, if they are made from balsa. The trick is to take the thickness off without going too thin. Look at the profile of the wing on the plans/instructions and try to match that.

Don't leave a step!

Oct 26, 2007, 06:12 AM
If it ain't broke...break it!
Hangtight's Avatar
Thanks Tom. Is there any sense in glassing the ailerons, with perhaps 25g glass and PU varnish? Covering will be Solartex. Is this enough on it own to beef up the balsa?

More newb questions to follow
Oct 26, 2007, 08:03 AM
satinet's Avatar
I'm not an expert in glassing control surfaces. Although 25 is fairly light, I would say. You might find it easier just to back them with thin ply-wood. If you've got your bedlam yet, you'll notice that this is how Stan does it.

Covering films do stiffen things up a lot. Don't get too paranoid though, it's not a 300mph DS monster after all.
Oct 26, 2007, 08:18 AM
Not a Doctor
me_wantee's Avatar
I've glassed ailerons with 3/4oz cloth and CA before.
Works well and doesn't take too long. Then I spackled and covered them.
I felt like I had gone overboard when I finished though.
Oct 26, 2007, 08:48 AM
If it ain't broke...break it!
Hangtight's Avatar
Right, KISS it is then. Thanks.

More to follow when I've finished decorating. God, I hate decorating
Oct 26, 2007, 09:01 AM
Woodstock 1's Avatar

I'm busy building the LEG Le Fish, and noted the same thing - the ailerons are thicker than the sub-TE. I am wary of sanding the ailerons down - they seem pretty delicate to start with, and I doubt I will be able to match the nice machined profile they have at present. My thinking is, once I have finished taping/spackling/covering the whole wing, it will have increased in thickness, and should then match the balsa aileron stock, which I intend to just cover with profilm only.

If you've already sanded them down, I guess this is academic....

I'm taking photos for a possible build log, but I'm a bit cautious about actually doing the log until the plane is proven in flight....


ps. I'm also not supposed to be doing this, I'm supposed to be making cupboard doors....
Oct 26, 2007, 09:12 AM
satinet's Avatar
Chris, the thickness won't have increased that much.

However, i should say that you only really want to determine how thick your ailerons need to be after you've built the rest of the wing.

As I said, i've had to sand down every wooden aileron/elevon I've had (actually except Alula and Weasel-pro). That includes your Middle Phase Chris! One i had was about 1/4" thicker than the sub t/e!

It's not that hard, you just have to be methodical in your sanding and/or planing.

Please please please, for the love of sloping don't let your ailerons be thicker than the sub t/e
Oct 26, 2007, 09:57 AM
All work and no play
legliderman's Avatar
The ailerons need to be sanded to match the wing. Here in the states we are only able to buy them in generic sizes so I include the size over to fit as needed.
Oct 26, 2007, 10:01 AM
satinet's Avatar
exactly - they come in a generic sizes, so the maker is always going to get ones slightly thicker than than the t/e of the wing........
Oct 26, 2007, 10:18 AM
If it ain't broke...break it!
Hangtight's Avatar
I had a closer look at the situation, even to the point of printing off the MH32 section at the correct chord and comparing it to what I've already got. Part of the problem seems to be that in a perfect world, the ailerons should match the the section as plotted. When was the last time you looked at a section on Profili, for example, and the TE finished as a 2mm square edge? So it looks as if the best I can do is to thin the ailerons down as much as I can and still leave a bit of a square TE.

On another note, has anyone got suggestions as to the best/easiest/most accurate way of locating the wing hold down plates and transferring the hole positions (T nuts are already installed) to the wing?

I'm not supposed to be doing this either But the wife didn't seem to appreciate the explanation that this is more interesting than watching paint dry
Oct 26, 2007, 10:31 AM
Piscine Promulgator
surfimp's Avatar
There are always going to be compromises when building wings... especially when humans are involved in their construction.

To my knowledge, the most accurate airfoils are produced using CNC-machined wing molds cut from a solid hunk of aluminum or other very stable material. The wings are then hollow molded and to my understanding this is "as good as it gets"... at least until a bug splatters itself on the leading edge, or you accidentally leave the wing in a hot car and it takes a warp

For other building techniques - like sheeted wings or foamie wings as in this case - you just have to do the best you can.

Like Jack says, definitely sand down the aileron stock to match the rest of the wing. Even if it doesn't result in a perfect MH 32, it's going to be a hell of a lot better than having a 1mm step poking up into the airflow and probably separating it from the wing.

Oct 26, 2007, 10:40 AM
Woodstock 1's Avatar
Originally Posted by Hangtight
watching paint dry
No, no - you're supposed to be applying the paint, not watching it dry!

OK I stand (Partially) corrected - although I will still wait until the wing is completely finished before I match up the ailerons. I agree that a step up would be airflow suicide, but I also don't want to end up with a step down (ailerons too thin)!
Oct 26, 2007, 10:44 AM
If it ain't broke...break it!
Hangtight's Avatar
Just been looking through the manual and the 1D extras Jack sent with the kit. The wing taping instructions use a 109 wing as an example. This has a forward swept TE that means opposing strips of tape carry over onto the opposite wing half, giving 2 layers of tape over a large portion of the wing. The 1D has a straight TE So do I lay down an extra layer of tape on the bias over the first layer, or is one layer sufficient?

Thanks for a great kit Jack. I'm really enjoying the build and learning loads (with the help of everyone out there )

Thanks for the timely advice on matching up the aileron thickness after the wing is covered. Saved me from making to much dust!
Oct 26, 2007, 12:12 PM
All work and no play
legliderman's Avatar
If you are not planning on DS's this plane one layer should be plenty. But if you want a higher wind plane a second layer starting from the front is strong.

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