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Old Oct 09, 2012, 03:32 PM
I don't like your altitude
Stupot46's Avatar
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I see what you mean about it going nose in when the fin touches down.Did you do any reinforcement of the leading edge carbon tube joint?
Regards Stuart
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Old Oct 09, 2012, 04:15 PM
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Knoll53's Avatar
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The leading edge is a black FIBERGLASS tube. Looks like carbon doesn't it ! Goodwinds.com doesn't even sell fiberglass colored fiberglass tube any more....the black is so popular.

At the nose, the center 3 bays will be skinned with 1/32" plywood and heavily reinforced with fiberglass from the inside. Might add a "bra" of the red Kevlar over the nose. similar to the handle at the fin.

Kent
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Old Oct 10, 2012, 05:41 PM
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Trailing Edge

The TE is 1//32" plywd. with 25K CF tow top and bottom. Trying out the new tow wetter for this little layup. Need to come up with good way to squeege the tow as it exits the wetter so that the wetness can be adjusted.

Kent
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Old Oct 10, 2012, 07:43 PM
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and now....a video
New Tow Wetter - TE lay up (14 min 57 sec)
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Old Oct 11, 2012, 06:12 PM
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Got the floor boards in with glass reinforcement.

Kent
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Old Oct 11, 2012, 06:35 PM
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Test Balance

I was HOPING that this wing would balance out without a fuse because of the wing sweep.....but not enough. The test balance, even without elevons shows an aft CG even with a long nose and 2 oz. of trim weight up front.

It looks like there is a fuse in my future.... I guess I won't need to build that main skid after all.

Kent
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Old Oct 11, 2012, 08:46 PM
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Fuse

With the help of Rhino 3D came up with some templates to cut profiles in foam, then sanded to shape. Started with one layer of light glass just to get some thing stuck to the foam. When this is cured, I'll add layers of this and that until strong. Not really sure how this goes. Glassing is not my thing.

Kent
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Old Oct 12, 2012, 07:38 AM
Herk
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Kent, It'd be interesting to see how it balances without that big tail on there. When you were building it, I thought it might create balance issues.

Might be worth looking at alternatives.
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Old Oct 12, 2012, 09:35 AM
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Hi Herk,

The tail is permanently installed at this point. It is built stronger and heavier than needed by most pilots, but stronger ships serve me better. I'm happy to pay the price.

When it comes to balance and the tail there is not much need to remove it in order to perform a balance test. The entire tail assembly weight 45 gms, IIRC. The assembly's CG could be estimated, then moments about a point to do a "what if".

I could balance this plane without a fuse, but that would require 8 to 10oz of lead in the nose which would be fine for a slope machine, but I'd like to thermal this one. The fuse should be lighter overall.

Kent
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Old Oct 13, 2012, 12:37 PM
the answer 42 is
Switzerland, AG, Lenzburg
Joined Jan 2006
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Wowow Kent, I leave you for two weeks and you come with another beauty definitely on my bucket list.

For the fin, I could advise a fully symmetrical delta shape. A collegue developed this idea for his DLGs and it reduces drag significantly. I will post some pics ASAP.

EZ
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Old Oct 13, 2012, 05:58 PM
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A fin of this caliber needs a comparable fuse to provide balance. Test balance without elevons or covering. .. 2oz. of nose lead looks good for now. Still have to gouge out the foam from the fuse.

Kent
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Old Oct 13, 2012, 06:25 PM
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Just for reference, 10oz. is needed to balance without the fuse. What a difference a little moment arm makes.

I'll test fly it in this configuration in order to determine the real CG before casting permanent lead in the nose installing the fuse.

Kent
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Old Oct 14, 2012, 02:37 AM
I don't like your altitude
Stupot46's Avatar
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I must say I prefer the look of the fuselage version.Adds more than just a mechanical advantage.
When you say "gouge out the foam"do you mean all of it,just leaving the glass shell?Can I ask what weight of fabric you used,how many layers and how you applied them.(education education education as our Mr Blair used to say)
Regards Stuart.
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Old Oct 14, 2012, 10:08 AM
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Quote:
Originally Posted by Edwinzea View Post
For the fin, I could advise a fully symmetrical delta shape. A collegue developed this idea for his DLGs and it reduces drag significantly. I will post some pics ASAP.

EZ
Feel free to post not only the delta shaped tail but anything related to planks. If my humble plank has spurred on some ideas, sketch them up an post them here.

Quote:
I must say I prefer the look of the fuselage version.
I noticed the same thing ! I not sure if I am just conditioned to seeing the conventional fuse/tail layout but it needs the fuse to visually balance the tail. Would I like to see a shorter nose, such as the Samurdactyl....yes I would, but that's just a matter of degree.

As far as glassing goes, I'm afraid that I'm such an amateur that I don't keep track of the glass that I have in stock. This one starts with one layer of light glass (2oz?) laid up on a wetted out foam core. Cure. Then a layer of heavier glass (8oz) was applied to the work with 3M77, then wetted out. All very resin rich.

With the foam core in tack, it was rigid, but when the foam was gouged out at the rear portion, it was flexible as a shell only. Strong enough for light duty thermal flying. Then I added 50K of CF tow each side with some Kevlar patches. I'll fly it un-painted, so if it breaks, reinforcement will be easy. I post some piccies later.

As a rule of thumb Stuart, I'd start with 2 layers of medium glass to make a rigid shell. Then gouge out the foam and add more layers to suit your needs.

Kent
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Old Oct 15, 2012, 01:42 AM
the answer 42 is
Switzerland, AG, Lenzburg
Joined Jan 2006
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For me it looks better without fuse. But I muss say that it will certainly help with the plane orientation and attitude

EZ
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