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Old Mar 01, 2015, 03:50 PM
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Build Log
Goshawk, a 1.5M DLG Flying Wing.

G'day Folks,

I stumbled across plans for a 1.5M dlg flying wing on a German (I think) forum and was really impressed with its looks and performance called the Little-Wing. I've decided to have a go at building one with several of my own modifications.

It will be a 2 piece wing for ease of transport. I'm hoping for a flying weight of @ 330gms. Servos will be Hyperion DS09-AMD weighing 9.2gms each.

The layup is heavier than I would like but I have the material and lighter stuff is prohibitively expensive. D box is 100gsm spread tow, behind that is 67gsm kevlar.
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Old Mar 01, 2015, 05:02 PM
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very attractive layout -- will enjoy watching this one go - H
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Old Mar 02, 2015, 12:14 PM
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Wow, that bias spread tow is just gorgeous. It makes my lay ups look like Nice!
Would like to see some detail at the D tube. You've got a nice lay up technique.
I trust that you applied the spread tow directly to the foam with 3M77 via the baking paper transfer technique.
Do you use a light layer of glass over the spread tow and kevlar just for finish?
I'm thinking of buying 170 gsm kevlar for general use. (Style 285 is a 17x17, 1140 denier, 5 oz, 4-harness satin [crowfoot] weave, thickness ~10 mils) I suppose conventional thought would be that that is way too heavy for our little models.

There is a lot of sweep to this one. Cool design. I would think that the joiner area would have lots of torsion during discuss launch. So you will have the main joiner plus some alignment pins? Looks challenging.

Also, I was unable to discuss launch my SW-2 which had similar sweep. Planks discuss launch fine. It's just the swept wings that are the challenge.
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Last edited by Knoll53; Mar 02, 2015 at 12:31 PM.
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Old Mar 02, 2015, 02:41 PM
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Thanks Herk and Kent.

The spread tow is super easy to use. No transfer paper required, just cut it and it doesn't fall apart. A 20mm strip of spread tow was also used for leading edge stuck with 3M and ironed. Spread tow was layed up on the mylar with a 6mm, 1/4'', overlap of kevlar at the curved line. That's it, no glass. Wet out then hard roll with absorbent paper to debulk.

Yes, there will be some challenging aspects to the build. Joiner plus alignment pin near the leading edge. Fins went in the bag yesterday. Now I have to work out how to attach them to the wing, there's not much meat there at the tip especially taking a throwing peg into account.
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Old Mar 02, 2015, 06:25 PM
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Awesome build ,your quality is increasing at a rapid rate . Make sure you keep it alive so I can see it at Manila.
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Old Mar 04, 2015, 01:49 AM
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the answer 42 is
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That looks gorgeous, now I need one :P

EZ
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Old Mar 04, 2015, 03:14 PM
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Well done mate.......it will be very interesting to see how she flys....where does 'Goshawk' come from
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Old Mar 05, 2015, 04:05 AM
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Whiskey Tango Foxtrot
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Quote:
Originally Posted by PlayinInTheParK View Post
Awesome build ,your quality is increasing at a rapid rate . Make sure you keep it alive so I can see it at Manila.
Quote:
Originally Posted by Edwinzea View Post
That looks gorgeous, now I need one :P

EZ
Quote:
Originally Posted by Grab View Post
Well done mate.......it will be very interesting to see how she flys....where does 'Goshawk' come from
Thanks Shane, Edwin and Andrew.

Where I grew up Goshawks were a common sight hovering motionless 50 feet above and open paddock before dropping like a stone to swoop on their prey.

The fins are now complete at 12.5 gms each. I tried a quick CG mock up and it looks like I'll need to add a pod to get the battery forward rather than adding a heap of lead to the nose.

Balsa root ribs faced with carbon fiber have now been glued in with splooge.

Hoping to get the fin tubes added tomorrow and glue in the incidence pin tubes with the correct 70mm anhedral.
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Old Mar 07, 2015, 02:50 PM
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Servos and control rods go in today so I'm hopeful for a maiden flight.
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Old Mar 07, 2015, 02:58 PM
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Looks even better in the sun.
will you use ball links at the elevon horns?
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Old Mar 07, 2015, 03:40 PM
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Yes I will be using ball links and carbon rods.
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Old Mar 07, 2015, 09:08 PM
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Maiden flight report

Well, ............it flies.

After a few tentative hand tosses and continually moving the battery back I got it to the point where it will glide ok. I then summoned up the courage to try a gentle side arm launch. Well, that went ok so I worked up to giving it a fair heave but with only a half turn arm toss.

Launch height was reasonable and the oscillations smoothed out very quickly. The last toss cracked both fragile wing tips so I need to beef them up a bit. I didn't get a chance to carry out a dive test. I'll make a fuselage pod this arvo now I've got some idea where the battery might end up.

Flying weight at the moment is 350 gms with a 50 gm battery.

Very happy so far.
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Old Mar 07, 2015, 09:50 PM
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So you were able to use the throwing peg and do a typical discuss launch? Cool! That's good news. Not everyone can DL a swept wing. Congrats.

This guy has managed to come up with a workable technique.

The winglets will require some study to find a strong lightweight solution. Of course heavier winglets will require more nose weight.

Where did you place the throwing peg? At the front corner of the wing tip?
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Old Mar 07, 2015, 10:32 PM
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Thanks Kent, No throwing peg fitted yet, I've just been gripping the wingtip with my fingers near the spar. I wanted to test fly it first.
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Old Mar 08, 2015, 06:28 AM
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Very stylish, it's good that you like it.
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