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Feb 05, 2010, 02:02 PM
Caution:Makes sharp left turns
Troy's Avatar
You might want to ask Sayno2glo what he was using in his homemade Batleths. I'd expect that to be a good starting point but the Mubu has a very different center section with regard to how the uni's cross over.
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Feb 16, 2010, 05:20 PM
Speed King
MarkChinery's Avatar
Some more Pics for you..

Foam cores are cut. Bottom outer stuck to Board


Here you can see the Anhedral buit in during the core cutting process


Here is my Son holding the wing


thin ply strips to create rasied lips on control surfaces.


one of the cores & top skin(its upside down)
Feb 16, 2010, 07:00 PM
Needs brain lubrication
biber's Avatar
Thread OP
Looks great!

And even your son seems to be proud of you.

You can, btw, deliberately extend the ailerons more towards the tip if you like.
The ailerons as originally designed are very well suited for pylon racing, but for fun you might want a bit more roll response.
You just have to make them light and stiff, like you have to with all the pylon stuff, anyway, to prevent flutter.

biber,
having a set of wing molds about ready for applying relase agent now
Feb 17, 2010, 04:23 AM
Registered User
Paul.S's Avatar
very nice Mark
Feb 17, 2010, 08:11 AM
Speed King
MarkChinery's Avatar
I could do with some advice on what carbon spar thickness & width you guys recomend for F5D?

For the first model im not going to go carbon skin. im glong to glass skin with carobn tows zig-zag down the wing + tows leading & trailing edges.

What glass skin thickness/weight's should i use?
Feb 17, 2010, 08:42 AM
Needs brain lubrication
biber's Avatar
Thread OP
I'd go with two layers of 80 g/mē bias for the skin.
Or maybe two 50 g/mē, if the wing has to be light.
That might not be FAI F5D proof, but certainly enough for a fair 200 km/h.

If supported by zigzag carbon tows, I think it can hold up to the 300 km/h region.

Carbon tow in the LE is perfectly ok, but please not in the TE, especially not in the controlls.
In order to prevent flutter it is vital to keep the TE of the controls as light as possible.

Are you familiar with bagging composite wings?

biber
Feb 17, 2010, 08:53 AM
Speed King
MarkChinery's Avatar
Ive not bagged before but have seen it done.

for this im going to do a like a milar on the bottom foam blocks that you see & them glass on top of this & press in the foam cores. The core will have a spar cap of carbon built in during this side skinning process. then cut in the wingo to insert the par web & then repeat the process for the top skin/spar cap.

To keep the control surfaces from flexing to reduce flutter i was going to lay in carbon tissue to give them more strength, This might be better than a tow along the whole TE as its very light but ads quite a bit of stiffness.
Feb 17, 2010, 09:52 AM
Needs brain lubrication
biber's Avatar
Thread OP
Sounds right.

biber
Feb 18, 2010, 02:19 PM
Registered User
Humm,
That should become really great looking (and flying)!
Feb 22, 2010, 08:59 AM
Speed King
MarkChinery's Avatar
Hi biber/paul,
How did you work out the best position for the main spar as the various stations have variying thixcknesses for spar location.

Ive worked out for the transition form 120mm(m120) to 160mm(m160) both sections have a max thickness about 44mm from LE. did you use this for your spar location or some other references?
Feb 22, 2010, 04:36 PM
Needs brain lubrication
biber's Avatar
Thread OP
If you run a straight line fron the tip LE towards about 10 mm behind the centre LE it should be roughly parallel to the straight part of the LE.
I'd take that line as the forward border of the spar.
5 mm more or less do not really matter here, anyway.

The other part of the spar (the unswept part) is just as far aft as the elevator control surfaces allow.

biber
Last edited by biber; Feb 22, 2010 at 04:43 PM.
Feb 23, 2010, 04:15 AM
Speed King
MarkChinery's Avatar
Your new layout looks like the spar is not parallel to the leading edge. is this not going to cause issues with the spar strength?

Im going with your original loyout on the right. the smaller ailerons will be fine for F5D.
Feb 23, 2010, 06:03 AM
Needs brain lubrication
biber's Avatar
Thread OP
Yep, it's not quite parallel to allow for more space for the elevator servos.
Maybe I place the spar again like shown on the right, if I find there is enough space for the servos, anyway.

In the prototype they did actually fit into the wing.

If you don't mind an extra 10 g or so, it's no big deal to move the spar forward.
The slightly thinner spar is easily compensated by some additional uni carbon.

biber
Mar 05, 2010, 02:35 PM
Speed King
MarkChinery's Avatar
progress is slow but there is some.. top blocks are on their board. Milar wont go round the compound curve of the wing so im putting parcel tape on the outers to form the moulding surface. Saface will be fairly smoth any small imperfections ill sort after.



Mar 05, 2010, 03:56 PM
Caution:Makes sharp left turns
Troy's Avatar
A helpful hint: A Monocote/covering iron on lower heat can help conform that tape to stubborn curves and corners. It also helps stick it down. Key being correct heat settings. I use to use colored packing tape and a covering iron on my EPP slopers to make the tape go around compound curves. It did an amazing job.


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