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Jun 06, 2003, 12:06 AM
Registered User

Need Help on building a Flying wing

I folks
Have been flying speed 400 planes in India for a while now and i am keen in building a zagi type flying wing made of high density white foam and powered with speed 400 6v.
I have found couple of plans, one that i plan to build is from this site
have enclosed the image of the plan

I need help in the airfoil to use whcih is best airfoil for flying wings
what kind of battery configuration I have Kr600AE cells
What root and tip chord, whats the best span for speed 400 power as i am not after speed but duration and glide to begin with

All the wing flyers please advise, thanx in advance and will keep you posted on my success

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Jun 06, 2003, 02:12 AM
Registered User
schoey's Avatar
Just follow the instructions on the site, the tip wing section and the root wing sections are both there for download, and keep the span as is. 600AE's would work but you will get very short flights, and may have to add weight to balance, a better choice would be 1400AE's or 1300CP's (or anything suggested for a zagi).
They fly quite well, I have seen a few of them on the slope and electric (I am a member of rebel).

Jun 06, 2003, 05:34 AM
Registered User
hi grant
Thanx for ur advice, will build with the same span and sections,
I do have 1400 sanyo cells, should try themm too. what kind of up degree thrust is required onthe motor mount, whats a good a all up weight ready to fly and how do you launch this i mean wher e do u hold it to toss it into the air?
Jun 06, 2003, 12:12 PM
Lift is Good!
Cubby Boy's Avatar
I built a glider using the free plans at Zagnuts.

You could scale the plans down a bit (from a 53" wing) to a 30" - 36" wing to suit your needs.

It built really nicely.

Jun 06, 2003, 11:23 PM
Registered User
schoey's Avatar
I think everyone that has made one has just bought a zagi canopy from the local hobby shop, so that has taken care of thrust angles, if you can't find one of those, you can make one from correx as for wieght, I'm not sure around 20oz maybe?? Since buying a brushless motor I haven't weighed anything.

Jun 07, 2003, 12:41 PM
Barrett's Avatar
Hey Prashanth, great to see that you are getting into wings!
Ive had great success using a MH45 airfoil on my S400 wings, I use the free program Profili to modify them some (reflex, camber, thickness, etc...) but even a "stock" MH45 would work well.
You can find Profili here...

As for the thrust angle, its really not as important as you might think for our small "toys" Ive built several different wings, and several different mounts for each wing that had different thrust angles. All of them flew well and any difference could be made up with more or less elevon "up" trim. I even tried a mount that put the motor shaft in line with the center line on the airfoil. It worked well also. But, you should probaly put in a few degrees "up" thrust because this will eliminate the need for more elevon up trim, which I guess would mean slightly lower drag.

Those demensions look like a great starting point for you first project. Its always a good idea to try somthing that is flight proven when you try new building technics. Foam cutting is a hobby all by itself! Once you get your first one flying you will be dreaming about a CNC cutter so you can start pumping out wings!

Here is a link to a construction thread complete with pictures of my first solid wire cut foam wing. It flew great on a S400 and 7-8 600AE's. Then I put a 16/15/3 on it and WOW!

Good luck and keep us posted!
Jun 08, 2003, 04:57 AM
Registered User
Hi barret
Thanx for your reply and nice to read your wise words on wings, saw ur videos of the skinni minni, ooof they are very fast, am still yet to begin with wings so thought will build one slow flyer before geting one of those micro blasters, on the wing scene.

I have upgraded from my GWS TX to a Futaba T6XA which I got from ebay ...just got it after a got amount of emails and postal vists.... I was crippled all these days with the GWS TX soon i will have my speed 400 wing and looks like i will be bitten by the wing syndrome. I also came across another airfoil section called the sipkill that seems to be good for wings as well.

Will keep u posted and Thanx again
Jun 09, 2003, 05:06 AM
Registered User
hi barret
your thread on the wings has been extremely usefull and informative, I plan to make a bow too, as the hot wire that I have is a stationary one on a ply board and is a only 17''wide. The plans that i have are for a 42'' wing span i plan to reduce the wingspan to 32---36'' what should be the root chord, tip chord and the sweep back angle be?

i have found very high quality foam thats really strong, you can stand on them and it doesnt dent, each sheet measures 2 feet by 4 feet apprx and is 2 inch thick, its cost around 125 Rs each thats abt 2.5$
its supposedly used in the boat building industry, will post the cut cores soon

happy landing to all
Jun 09, 2003, 12:23 PM
Barrett's Avatar
First i would make sure your foam isnt to heavy. It sounds pretty tough, which could mean excessive weight. If you can, get a small piece of white EPS and weigh it, then cut a piece of your foam that is the same size. If the weights are close then go ahead with cutting your cores. However it you like the foam then use it anyway, it will at least last a long time. Just remember that every littl bit of weight you can save WITHOUT sacrificing to much strength is helpful.

On the wing that I cut, I think the demisions were...
Root 11"
Tip 5.25"
Sweep was between 15" and 17" I cant rememer exactly.
Span 36"

Im at work so Ill get back to you again later, but those should get you started.

Good Luck!
Jun 09, 2003, 09:57 PM
Registered User
I did try and cut one sample wing core, before that I made a bow from a bamboo stick that was lying around, made templates and i cut the core, the first try came quite okay. There were some uneven surface on the top of the leading edge, but the bottom and trailing edge came quite good..... Problems i think are the wire is not too hot as its rather very very slow in the foam, I forgot to sand the templates and so on couple of points i found the hot wire getting stuck to the template.

I figured since the root and tip chords are different in sizes, the hot wire thru the root chord has to move faster when compared to the tip chord......learning experience it has been
I agree fully with you barret. At the end when I got a wing core with two beds i was quite thrilled

I will do some weight measurements today in my lab on the foam that i used
here is the specs of the wing core,
root chord 11.5'', tip chord, 5.25'', half wing span is 19"

this core doesnt flex at all its very high density, will post the measurement of wt details by evening

Thanx to all wing flyers esp to barret and shoey

pics to follow as soon as i find a dig cam

have a nice day guys
Jun 10, 2003, 06:14 AM
Registered User
hey I found out the density of the foam from my friend who got it
the foam that i plan to use for my wing cores are 31kg/m3

Is too heavy?

I dont really know how to explain this, in case if any of you have had any success with this kind of foam please do let me know
Jun 10, 2003, 01:06 PM
Registered User
Pook's Avatar
If my maths is right i think 31 kg/m is
1.9 lb/f so it is on the heavy side but i wouldnt have thought out of the question...

Jun 10, 2003, 05:54 PM
Barrett's Avatar
Sounds OK, and I think your math is spot on Pook.
In fact many of the popular EPP flying wings are made of 1.9 EPP, I think And most of them are designed to fly very nicely on a S400.

Yes, the side of your cutting at the root will have to move faster than the tip side. Try to make the wire exit at the root TE and the tip TE at the same time. It takes a little practice, but you will get it eventually. The good thing is that nearly any core you cut will fly well (if all the demensions, C of G, weight, power loading etc..... are good) even if there are a few imperfections in the surface. I try to make my wings perfect everytime because I sell them, but I keep the ones that I mess up on because they will come in handy for some full contact pylon racing one day!

Do you know what kind of foam you are cutting? Is it possible that it is 1.9 lb EPP? Just curious, because it sounds like good foam for a combat model.


BTW the weight of my S400 wing in the above link came out to just under 16oz, with a 8 cell 600AE battery pack. That was with 1 pound white EPS.
Jun 11, 2003, 12:12 AM
Registered User
is there any way to find out the difference between EPP and EPS to be honest I have no clue on this, I'll check with the dealer on this, but for around 100 RS its worth the money as a couple of wings can be built with it.

I am still playing around with my hot wire, what is the volts and amps that you guys are cutting

my bow is 30 inch long, and the wire is a 100ohm wire

is there any thread that describes hotwire cutters on the zone
Jun 11, 2003, 01:44 AM
Registered User
schoey's Avatar
You can squeeze EPP down between your finger and thumb and it will bounce straight back, it is also quite flexible, whereas EPS is brittle, if you squeeze it, it will dent, if you try to flex it, it will snap.

The EPS I have seen used in boats is definately not EPP, but you might be lucky.

I think there are probably more scientific ways of differentiating between EPP and EPS, maybe solvents or heat (I think EPP will handle both better).

Either way, as Barrett says it will fly just fine if weight is fine, you might just end up with a slightly weaker model, but thats what tape is for anyway.



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