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Old Feb 24, 2012, 03:59 PM
SWR246
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Joined Nov 2011
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Firebird Commander Wing DLG?

What do people think of a Firebird Commander wing (under cambered) being used on a scratchbuilt DLG. Its lightweight and high lift. My old Firebird Commander would glide for ages on it, and thats a lot heavier that the DLG would be. Maybe I could cover it in light fibre glass to make it a bit stronger and more ding-proof, the wing is quite strong anyway though.

What do you think...possible?

Wingspan: 40 inch - 1 meter
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Old Feb 24, 2012, 05:07 PM
Dub Cult.
Long Island NY
Joined Feb 2011
95 Posts
Funny you say that I have one in the making at the moment. Its actually a fairly rigid wing so I cant see it not working. I also used the Vtail to try but I think that its going to need a standard rudder/elevator so you can really launch it. Ill post pictures later
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Old Feb 24, 2012, 05:50 PM
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USA, MI, Grand Rapids
Joined Apr 2007
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That idea is so crazy it just might work!!!

I like it....

keep us posted

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Old Feb 25, 2012, 04:54 PM
SWR246
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Do you think it would be worth putting some light fibre glass on, or leaving it how it is and therefore lighter?
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Old Feb 25, 2012, 08:36 PM
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USA, MI, Grand Rapids
Joined Apr 2007
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Light is always good. It kind of depends on how stiff and tough the wings are to begin with. Perhaps a strip of carbon top and bottom to transfer the energy at the launch peg to the center would be smart.


Glass will add dent resistance and reduce twisting flex. If you feel you need the glass use .50 or .75 ounce glass.

Step one...A light spritz of spray adhesive.
Step two... drape the glass over the wing. ( a helper is HUGE for that step)
Step three.... DON"T USE EPOXY... brush on Minwax Polycrylic in 3-4 light coats. with an hour of drying time between.

The DL-50 from Mountain Models employs this method....here is a link to the instructions. http://www.mountainmodels.com/images/manuals/dl50.pdf
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Old Feb 26, 2012, 03:39 AM
SWR246
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Thanks, i'll use that method, i'll probably get working on it soon and post updates on how it goes.

Thanks again
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Old Feb 26, 2012, 11:06 AM
Dub Cult.
Long Island NY
Joined Feb 2011
95 Posts
Here is my current build up.





Just used an old arrow shaft for the boom and a little piece of balsa soaked in thin CA for a wing mount. Now if you notice the little wrinkle in the wing its there for a reason I added a touch of dihedral to it and this way I wouldn't have to add any more weight with a glued seem of some sort with a cut in type. It seems to be holding just fine and did nothing structural as far as strength.

Now on to the stiffness of the wing, this thing is stiff I mean the way you see it there is pretty bare but I can take the plane and hold it as far out on the wing tip as possible without a single degree of flex.

For the controls I was going to use an ar6400 brick to save even more weight but I don't think it would be able to fly in a farts breeze being that light. So ill be going with 2 6 gram servos with a string spring setup and a 2s 180mah lipo. It should be light and put enough weight up front to hopefully balance it out. Only problem I'm having is finding a canopy to use I'm going to Walmart later to try and find some roundish packaging that I may be able to cut into something.

I'm excited to see your build! Keep us posted.
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Old Feb 26, 2012, 11:17 AM
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United States, CA, Tehachapi
Joined Jun 2011
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The V-tail will cause problems with a discus launch. Just warning you. Without any vertical area below the boom, it'll probably roll hard toward the throwing peg. The V may also cause it to pitch down during the initial yaw after release. The imbalanced forces during that yaw will also create a strong torsional load on your tailboom, and it could fail.

Brandon
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Old Feb 26, 2012, 11:40 AM
a.k.a. Matt Nelson
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North Tustin, CA
Joined Oct 2008
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Quote:
Originally Posted by bwill6 View Post
The V-tail will cause problems with a discus launch. Just warning you. Without any vertical area below the boom, it'll probably roll hard toward the throwing peg. The V may also cause it to pitch down during the initial yaw after release. The imbalanced forces during that yaw will also create a strong torsional load on your tailboom, and it could fail.
Maybe. A lightweight plane like this might be OK with the v-tail. Remember that the original Elf had a v-tail, and people threw the crap out of it without failure, and they actually launched pretty well. I really doubt you could generate enough force with this airframe to break the boom. Yes, crucifom tail is more appropriate, but if the v-tail is already built, I'd just try it. Can always change it later...
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Old Feb 26, 2012, 11:41 AM
Dub Cult.
Long Island NY
Joined Feb 2011
95 Posts
Oh I know it was built prior to doing any real research into tails but its getting torn down today probably because now I have motivation to get on it. Only thing is I dont really know how large and what shape to make the stabs.


(sorry not trying to thread jack)

I guess because they are mounted I really should just give it a shot whats the worse that could happen? I have to just cut it off and make a new set?
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Old Feb 26, 2012, 03:15 PM
SWR246
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Joined Nov 2011
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C.raynes, thanks for uploading the pictures. I was looking at an arrow shaft today thinking it might make a good boom as well. I will try to make the front pod out of really light fibre glass to house the receiver, three 5 gram servos (one for each aileron and one for elevator, do I need rudder?) and a battery. I will probably use a carbon fibre tube for the boom. I will do that standard tailplane for DLG's.

The wing weighs 91 grams, so it will definitely not be glassed, I will just put some fibre tape over the leading and trailing edges.

To make the battery/receiver/servo pod, I might try making a foam pod, fibre glassing it, then using acetone to dissolve the foam from inside to leave a hollow pod. Anyone got any better/easier ideas?

Thanks again everyone.
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Old Feb 26, 2012, 04:15 PM
Dub Cult.
Long Island NY
Joined Feb 2011
95 Posts
Because your going aileron I wouldnt even bother with rudder. You definetly want to keep it as light as can be I would imagine and if you need the make it a little heavyier it would be better suited under the wings for ballast not just dead weight with another servo and linkage.

The arrow shaft is nice because well we have a ton around my house and it seems to be fairly thin walled yet extremely stiff and has enough room to run my strings through.


I just actually did the pod I made a blue foam mold and wrapped it in glass its a bit larger than I really wanted but Ill make it work. If it comes down to it ill just cut it up and shrink it as needed. Ill post some pics in here once I get some more work done worth showing.also for mounting the electronics I don't know how you plan on doing it but I mounted everything to a tongue depressor and glued that straight to the boom. I just used some hot glue so I can pop it off and move it around for CG changes if needed after a few flights.
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