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Jan 21, 2021, 10:48 PM
Fly crash order parts repeate
hi guys
Came across this on the art hobby forum thought it maybe of interest
I wouldn't cover an ArtHobby wing with laminate.

If the surface of the wing becomes too "perfect" (too smooth) your glider will become more sensible to stalls at low speed. With the smooth wing surface the airfoil will break without warnings.
The not so smooth surface of the wooden wing will generate lots of "micro-turbulences" on the wing, wich will result in a much smoother stalling behaviour at low speed.

I can confirm this in real live :
My first ArtHobby is a Solaris that I bought second hand and wich is oracovered. It's a real stalling pig at low speed.
On the other side, the Orion and the Silent I assembled myself, and painted with lacquer, have a very predictible stalling behaviour, and are lots less stressing to fly !
All three gliders have the same SD7080 wing profile.

Cheers Watho
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Jan 22, 2021, 03:42 AM
Registered User

20min session


Early morning dialog:


Honey, can you please go to the grocery shop for me?

???............ ....No problem!


.

..

...

....
most of my sessions are unauthorized !
Last edited by a filos; Jan 22, 2021 at 11:14 AM.
Jan 22, 2021, 03:47 AM
Registered User
Quote:
Originally Posted by Watho 46
your glider will become more sensible to stalls at low speed. With the smooth wing surface the airfoil will break without warnings.
I never consider stalls a big problem with DLGs. They are so light that any stall will recover with a 1-2m height loss.
Jan 22, 2021, 08:45 AM
Registered User
Thread OP
Antonis I’m also having to increasingly slide my time with the dlg past my wife! Haha. We def have to bargain sometimes

Sweet. 32.8 grams. So the core/spar was 24 grams, glass/minwax (put on rather liberally this time) and epoxy added 9 grams. Wing complete. Newly acquired 1500 grit sandpaper made it very smooth even though it still appears matte
3mm x1mm carbon blade imbedded vertically and a 1mm carbon rod is in the leading edge. Twice as stiff as it really needs to be. :-). Also smeared 30 min epoxy very thin in the leading and trailing edges with my finger.

Will get them mounted to the 3mm shaft today.


Separate thought. Mix and pour foams are used in boat hull construction for coast guard required flotation and have the same properties as XPS once they expand and dry. You’d need a nicely milled form out of corian or even steel, but I wonder if anyone has ever just poured a wing core out of mix and pour foam? After completion you could turn around and use the same form to laminate the skins on I would think?

A family friend owns a steel shop with a CNC milling machine. I may run the idea past him. Shop at the local marina down the road sells the 2 part mix and pour foams. Tiny amt needed for a wing core is not very expensive. Scraps of corian are really cheap from any counter top manufacturer locally. I wonder if I could pour a literal snipe or BAMF core if I had the form made??? Going to this length and it would be a full size 1.5 m for sure. I’ll let y’all know what our friend thinks.

Update: well I’m not that original. Guys on YouTube doing this in Australia. A lot more problems come with this type of method than one would expect. Oh well. Will think on a gravity fed Hotwire setup soon. Tried and true. :-)
Last edited by Dan81; Jan 22, 2021 at 09:55 AM.
Jan 22, 2021, 09:00 AM
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Johns birds's Avatar
Quote:
Originally Posted by a filos
I never consider stalls a big problem with DLGs. They are so light that any stall will recover with a 1-2m height loss.
I did not know you are in this forum. That is good.
Jan 22, 2021, 09:14 AM
Registered User
Quote:
Originally Posted by Johns birds
I did not know you are in this forum. That is good.
Nice to have you here John!
Jan 22, 2021, 10:12 AM
Registered User
Quote:
Originally Posted by Dan81
Antonis Im also having to increasingly slide my time with the dlg past my wife! Haha. We def have to bargain sometimes

Sweet. 32.8 grams. So the core/spar was 24 grams, glass/minwax (put on rather liberally this time) and epoxy added 9 grams. Wing complete. Newly acquired 1500 grit sandpaper made it very smooth even though it still appears matte
3mm x1mm carbon blade imbedded vertically and a 1mm carbon rod is in the leading edge. Twice as stiff as it really needs to be. :-). Also smeared 30 min epoxy very thin in the leading and trailing edges with my finger.

Will get them mounted to the 3mm shaft today.
Excellent progress!

These guys are my go-to for hard to find items, here's their selection for 'sandpaper' products with grit finer than 2000:

https://www.mcmaster.com/sandpaper/g...pBox=sandpaper

I've been buying from them for more than 3 decades, and they are the best business I've dealt with, bar none.
99.9% error free, and they have *never* pushed back.
I've ordered from them, gotten the product, realized I chose the wrong thing or that it wasn't going to do what I needed.
Called them, explained my error, return shipping label sent to me immediately, no static at all, ever.
I've been to their warehouse here in CA, they had half a dozen UPS big rig trucks being loaded, and as soon as they were full , off they went.
They are not the cheapest, but *everything* I ever wanted from their catalog was in stock.
I could go on, but you get the idea.


Quote:
Originally Posted by Dan81
Separate thought. Mix and pour foams are used in boat hull construction for coast guard required flotation and have the same properties as XPS once they expand and dry. Youd need a nicely milled form out of corian or even steel, but I wonder if anyone has ever just poured a wing core out of mix and pour foam? After completion you could turn around and use the same form to laminate the skins on I would think?

A family friend owns a steel shop with a CNC milling machine. I may run the idea past him. Shop at the local marina down the road sells the 2 part mix and pour foams. Scraps of corian are really cheap from any counter top manufacturer locally. I wonder if I could pour a literal snipe or BAMF core if I had the form made???
If that shop is skilled at creating complex 3-D shapes, that's a great resource.
Not every CNC shop will be able to do a mold like you need.
An accurate, smooth 'organic' shape is not super easy.
I recommend going with the lightest material you can that will still maintain shape.
The tougher the material the less they will like doing the job, and it will then cost more.
Jan 22, 2021, 10:17 AM
Registered User
Thread OP
This would probably be free created after hours. I’m still going to talk to him about it to have the mold simply to mold a ‘real’ wing with in the future. Corian seems to be popular from what I’ve seen.
Will wait for a final design though later. Would have to decide on airfoil etc. a few more prototypes to do first. :-)

Good resource there. I Found this 1500 grit at Walmart in the auto detailing section actually. Worked great. This wing is noticeably smoother on the surface now than the original Snippet.
Jan 22, 2021, 11:32 AM
Registered User
Quote:
Originally Posted by Dan81
Sweet. 32.8 grams. So the core/spar was 24 grams, glass/minwax (put on rather liberally this time) and epoxy added 9 grams. Wing complete. Newly acquired 1500 grit sandpaper made it very smooth even though it still appears matte
3mm x1mm carbon blade imbedded vertically and a 1mm carbon rod is in the leading edge. Twice as stiff as it really needs to be. :-). Also smeared 30 min epoxy very thin in the leading and trailing edges with my finger.
The wings are looking very nice! I think this one is going to fly very good. Small RE are very fun to fly and easy to build.
Jan 22, 2021, 12:13 PM
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Thread OP
Thanks man. I think so too. Just glued the wings on. Hopefully can finish it this weekend. If not, for sure by next weekend.

Plan is to have a couple of these just for easy flying out the front door. And a couple of full house 1.2m ones to take to the flying field for ‘serious’ flying. Haha. And one more powered 1.2 m one just because I want to try it. :-).
Last edited by Dan81; Jan 22, 2021 at 12:41 PM.
Jan 22, 2021, 03:25 PM
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22 Ιανουαρίου 2021 (0 min 27 sec)
Jan 23, 2021, 02:32 AM
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Does anyone know, where to find the synergy wing profile? I am thinking of a 1m 4ch for my next project.
Jan 23, 2021, 04:35 AM
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@Filos:

Found this one:
https://www.rcgroups.com/forums/showpost.php?p=33941751
Jan 23, 2021, 05:44 AM
Registered User
Thread OP
Nice find. Eliminating the tip and having that be a double taper would make a really nice wing I think. Saved the file myself. Appreciate that
Last edited by Dan81; Jan 23, 2021 at 06:17 AM.
Jan 23, 2021, 08:51 AM
Registered User
Hey pod-builders, just in case you didn't see yet: kousakunin released a new video about his pod building method:
Scratch built DLG glider -Pod(Made of kevlar) (8 min 31 sec)


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