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Old Oct 23, 2012, 08:16 AM
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molond's Avatar
Australia, SA, Adelaide
Joined Oct 2011
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Question
Whats a good, CHEAP, wing core to fibre-glass?

I've been looking into making a fibre-glass flying wing but all the purpose designed wing cores seem expensive.

So I have been looking at off the shelf alternatives such as the Turnigy Tek-Sumo / Bonsai or the Red Eagles Fly-Wings-1

I have bought all these wing in the past and the Tek-Sumo and Bonsai are great wings but their top speeds were limited due to the rough skin. I just couldn't get the Fly-Wings-1 in the air (made it way too heavy, first kit built I did).

What I want to to know if these will act as good cores or you could also suggest some other core that will be good for a beginner (hopefully under $50 shipped to Australia). Also if I'm looking at this the wrong way just tell me, I won't be that humiliated.

Thanks anyway,
Darcy
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Old Oct 23, 2012, 06:09 PM
Mobius Cables... I got em'
chanyote66's Avatar
United States, TN, Oak Ridge
Joined Dec 2011
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If you have the patience, Hotwiring foam cores is easy... I would offer to send you some cores, but shipping alone will be way up there...

I built my Hotwire from a video on youtube, and get the foam from a local hardware store. I use EPS since I skin it any ways... I probably spent $30-$40 on the hotwire, and can cut wings for less than $10 each. I get my Airfoils and sweep from production planes to keep the performance in check. If you want to get fancy, for $100-$150 more you can build a homemade 2d cnc and connect your hotwire to it for precise foam cores...

But basically... Cut your own and save $$$
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Old Oct 23, 2012, 10:07 PM
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molond's Avatar
Australia, SA, Adelaide
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Quote:
Originally Posted by chanyote66 View Post
If you have the patience, Hotwiring foam cores is easy... I would offer to send you some cores, but shipping alone will be way up there...

I built my Hotwire from a video on youtube, and get the foam from a local hardware store. I use EPS since I skin it any ways... I probably spent $30-$40 on the hotwire, and can cut wings for less than $10 each. I get my Airfoils and sweep from production planes to keep the performance in check. If you want to get fancy, for $100-$150 more you can build a homemade 2d cnc and connect your hotwire to it for precise foam cores...

But basically... Cut your own and save $$$
Thanks, if I can find some good foam in Australia I would hot wire but the only eps foam I found was 250x250x25mm, nothing big enough unless I glue together a couple of pieces.

Just for reference, what foils/sweep do you use? Do you have one that is suitable for a glider/warmliner?

Thanks,
Darcy
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Old Oct 23, 2012, 10:20 PM
Mobius Cables... I got em'
chanyote66's Avatar
United States, TN, Oak Ridge
Joined Dec 2011
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I have been working on a variety of foils and most semi-symmetrical airfoils work well for RC, I usually try to stay around 25deg to 30deg sweep.

25mm would work but limits your size, if you stack two sheets together, hot wire them, then glue them you can encase spars inside the foam rather than cutting external spar channels.

Im focusing more on the MH45 airfoil with a root chord of 355mm wing span of 1320mm thickness of 45-55mm and a tip chord of about half the root chord.

This has been a very stable and scaleable design for both speed and slow flight. (I havent glassed one but im guessing that will increase speed quite a bit.)
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Old Oct 24, 2012, 12:30 AM
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Australia, SA, Adelaide
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Quote:
Originally Posted by chanyote66 View Post
I have been working on a variety of foils and most semi-symmetrical airfoils work well for RC, I usually try to stay around 25deg to 30deg sweep.

25mm would work but limits your size, if you stack two sheets together, hot wire them, then glue them you can encase spars inside the foam rather than cutting external spar channels.

Im focusing more on the MH45 airfoil with a root chord of 355mm wing span of 1320mm thickness of 45-55mm and a tip chord of about half the root chord.

This has been a very stable and scaleable design for both speed and slow flight. (I havent glassed one but im guessing that will increase speed quite a bit.)
Thanks, that from what I have seen looks an excellent foil for a flying wing. When I cut it, does it have to be two guides on either end of the wing or could I attach one end of the hot wire to a point so the outer tip is smaller that the root?

Thanks,
Darcy
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Old Oct 24, 2012, 09:42 AM
Mobius Cables... I got em'
chanyote66's Avatar
United States, TN, Oak Ridge
Joined Dec 2011
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I use a single guide and bolt the wire to the table. Then I find the angles I want "how much taper" and move the foam farther or closer to the pivot point for more/less taper. you can use two guides but you would need someone to operate the other end...
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Old Oct 24, 2012, 10:55 AM
Never trust laughing dolphins
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Quote:
Originally Posted by chanyote66 View Post
I have been working on a variety of foils and most semi-symmetrical airfoils work well for RC, I usually try to stay around 25deg to 30deg sweep.
Correct indeed , symmetrical airfoils generally don't work well anyway. The right balance between the top airfoil and lower wing area is what creates lift.
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Old Oct 24, 2012, 11:11 AM
Mobius Cables... I got em'
chanyote66's Avatar
United States, TN, Oak Ridge
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Originally Posted by PHMX View Post
Correct indeed , symmetrical airfoils generally don't work well anyway. The right balance between the top airfoil and lower wing area is what creates lift.
The balance between the two is critical though with flying wings, too far from symmetrical and it will have problems with speed, and the closer to symmetrical you get, the faster they have to be to create lift.
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Old Oct 26, 2012, 08:30 AM
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Australia, SA, Adelaide
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Quote:
Originally Posted by chanyote66 View Post
I use a single guide and bolt the wire to the table. Then I find the angles I want "how much taper" and move the foam farther or closer to the pivot point for more/less taper. you can use two guides but you would need someone to operate the other end...
Thanks, I though the pivot point method would be the best, well at least the easiest!

Darcy
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Old Oct 26, 2012, 09:42 AM
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Australia, SA, Adelaide
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I found a cheap website but...

I just found this web site: Flying Foam

And they will cut EPS and EPP to your specifications and at only $11+ for two EPS halves and $14.50+ for two EPP halves.

They will ship to the US, Canada and the UK but not Australia!

Any way, I've got I friend who happens to live quite close so the can re-ship it.

If you want to know, I may be going for a EPS wing of 48" (1200mm) [before sweep], chord of 8" (200mm) and foil of S5020 for $17 plus shipping.

Darcy
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Old Oct 26, 2012, 10:41 AM
Mobius Cables... I got em'
chanyote66's Avatar
United States, TN, Oak Ridge
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Quote:
Originally Posted by molond View Post
I just found this web site: Flying Foam

And they will cut EPS and EPP to your specifications and at only $11+ for two EPS halves and $14.50+ for two EPP halves.

They will ship to the US, Canada and the UK but not Australia!

Any way, I've got I friend who happens to live quite close so the can re-ship it.

If you want to know, I may be going for a EPS wing of 48" (1200mm) [before sweep], chord of 8" (200mm) and foil of S5020 for $17 plus shipping.

Darcy
Ya I have seen them before, and debated ordering from them, but hotwiring my own wings is down to about $5 a plane in foam... for both halves...

Root Chord of 8"? thats tiny... my 48" wing has a chord of 11" so I have room for batteries and FPV gear...
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Old Oct 26, 2012, 11:01 AM
AMA 937634
United States, AK, Anchorage
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You could also take a look at MWCores here: http://www.mwcores.com

He's got a bunch of different designs to choose from.

-Mike
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Old Oct 26, 2012, 11:32 AM
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molond's Avatar
Australia, SA, Adelaide
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Quote:
Originally Posted by chanyote66 View Post
Ya I have seen them before, and debated ordering from them, but hotwiring my own wings is down to about $5 a plane in foam... for both halves...

Root Chord of 8"? thats tiny... my 48" wing has a chord of 11" so I have room for batteries and FPV gear...
Unfortunately I don't have a hot wire setup so I'll buy the first set and make the cores next time. And yes 8" is tiny but it can go up to 12" for an extra fee. I think 36 x 6" is the largest you can go while still at the base price.

Quote:
Originally Posted by Stone1295 View Post
You could also take a look at MWCores here: http://www.mwcores.com

He's got a bunch of different designs to choose from.

-Mike
Thanks I'll check them out and compare the pair.

Darcy
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Old Oct 30, 2012, 09:55 AM
Foam Guy
Fort Collins, CO
Joined Jan 2011
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Hi All. Just wanted to say that we will ship to Australia and other international destinations if able. Depending on the country there are different size limits so it's not easy to offer our Quick Order and other stuff from the site with international shipping calculated correctly.

If you need something international we are happy to discuss options. For example, we just shipped a Mother Ship to Australia and had to cut the thing into a four panel wing and pack it into two boxes to get it to ship via USPS. Just email or call and we can figure out what is doable.

Darcy,
Just shipping to Australia from the US will probably cost you at least 50 dollars. For your budget I agree with the other posters about hot wiring your own foam. If you search you will find some good info on building your own hot wire bow and templates. Obviously we prefer people order from us, but we also realize we are not in everyone's budget. Just remember if you use EPS that you have to use epoxy resin as polyester resin will attack the foam. You may be able to use water based polyurethane and a light layer of glass over one of the off the shelf kits but I have never tried it. Depends on what type of foam as to quality of adhesion etc. I have read that brown paper and light glass in layers works well too. That method has been around for years, but again, never tried it. If you are just looking to clean up the airflow on a budget you may find that New Stuff/laminating film does the trick. We have used on both EPS and EPP with great success. Makes for a clean, strong, cheap (relative) wing. Lots of options.


Thanks!
Coby
FlyingFoam
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Last edited by cglusky; Oct 30, 2012 at 10:11 AM. Reason: Added Info
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Old Oct 30, 2012, 10:04 AM
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molond's Avatar
Australia, SA, Adelaide
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Originally Posted by cglusky View Post
Hi All. Just wanted to say that we will ship to Australia and other international destinations if able. Depending on the country there are different size limits so it's not easy to offer our Quick Order and other stuff from the site with international shipping calculated correctly.

If you need something international we are happy to discuss options. For example, we just shipped a Mother Ship to Australia and had to cut the thing into a four panel wing and pack it into two boxes to get it to ship via USPS. Just email or call and we can figure out what is doable.

Thanks!
Coby
FlyingFoam
Thanks for clearing that up, I am still thinking of what I going to get, checking my wallet and I am also going to wait until I have finished my exams.

I am probably going to get one of your epp quick cores, at most 48" by 10", how hard would it be to send that to Australia, and do you have an estimate for shipping cost?

Flying Foam has definitely just up to my #1 possible wing core shop!

Thanks,
Darcy

P.S. Thanks for the extra info, I'll get working on that hot wiring set during the holidays!
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Last edited by molond; Oct 30, 2012 at 10:31 AM.
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