$100 EDF Scratch Build Contest Flying Wing
#51

Now, Lets See if I can Make this hot wire bow cutter into a Gravity feed Cutter, I have a PHD in Watching others people do these things on You Tube
LOL, Lets see, I need 4 screen door rollers and some nylon cord and I think i have every thing else. I am Not Afraid to Try
I Fail My Way to Success
LOL, I will post some video of it Gravity Cutting if it works out, Take care and have fun, Chellie
[media]http://www.youtube.com/watch?v=S2TfNYSYLC8[/media]





[media]http://www.youtube.com/watch?v=S2TfNYSYLC8[/media]
Last edited by CHELLIE; 10-28-2014 at 05:34 AM.
#53




#54

Chellie,
Put a 'tail' on the formica pattern at the trailing edge, quarter inch by two or three inches is enough. Start your cutting on the tail and if the pattern starts to burn, nothing is lost. You'll cut the foam tail off at the trailing edge.
Good luck.
Put a 'tail' on the formica pattern at the trailing edge, quarter inch by two or three inches is enough. Start your cutting on the tail and if the pattern starts to burn, nothing is lost. You'll cut the foam tail off at the trailing edge.
Good luck.
#55


#56
Super Contributor
Join Date: Mar 2011
Location: Fond du Lac, WI
Posts: 1,048

I'm on the road right now or I would send you a photo, but I've used a piece of copper wire epoxied to my template as an "on ramp".
RE. hand guided cutting. I have had some success cutting highly tapered wings by starting in the center and cutting out towards the ends. I'd make a plunge cut at the 30% and cut either forward or backward. The area where you plunge in always has a ridge from changing direction but I was cutting a slot for a spar with a router on that line so it didn't matter.
I've also built a gravity cutter which is fine but fiddly to set up. I just cut by hand mostly. Put marks every 10% on the root and tip to help keep you straight as you go. Practice the cut with the wire above the blank a few times to get a feel for how much one hand has to move relative to the other. You should end the cut with your body relaxed and in balance. It's always better to start off less balanced and end relaxed than the other way around.
It helps to count while you cut. You should hit every 10% mark at the roughly same interval.
RE. hand guided cutting. I have had some success cutting highly tapered wings by starting in the center and cutting out towards the ends. I'd make a plunge cut at the 30% and cut either forward or backward. The area where you plunge in always has a ridge from changing direction but I was cutting a slot for a spar with a router on that line so it didn't matter.
I've also built a gravity cutter which is fine but fiddly to set up. I just cut by hand mostly. Put marks every 10% on the root and tip to help keep you straight as you go. Practice the cut with the wire above the blank a few times to get a feel for how much one hand has to move relative to the other. You should end the cut with your body relaxed and in balance. It's always better to start off less balanced and end relaxed than the other way around.
It helps to count while you cut. You should hit every 10% mark at the roughly same interval.
#57

Hi Joe
The bow cutter gets nice and hot, maybe to hot
its hard to control the Wire heat with A/C and a dimmer switch, might have to go to a 24V- 5 amp transformer with a dimmer switch, It keeps burning up the Formica patterns, I may need to use sheet metal patterns too, as the bow wire tends to burn notches in the Formica patterns, Oh well, Its all a Learning experience, I Will get it to work, the problem I am having right now, is that the Gravity feed foam cutter requires me to leave the bow wire on the pattern, untill the wire starts to cut the foam, and during those few moments, the wire eats into the Formica pattern and hangs up, I wanted to use a gravity feed cutter to Minimize Human Error during the cutting as this wing goes from 12" in the middle to 5 1/2" at the end of the wing and a gravity feed cutter will compensate for the wide and small end of the wing during cutting, Thats the plan anyway
I made a Redneck Gravity Feed cutter, it works good as far as the difference in area it will cut, large to small, just need to better regulate the heat on the wire, as to hot of a wire is not good, Take care, Chellie



#58

I'm on the road right now or I would send you a photo, but I've used a piece of copper wire epoxied to my template as an "on ramp".
RE. hand guided cutting. I have had some success cutting highly tapered wings by starting in the center and cutting out towards the ends. I'd make a plunge cut at the 30% and cut either forward or backward. The area where you plunge in always has a ridge from changing direction but I was cutting a slot for a spar with a router on that line so it didn't matter.
I've also built a gravity cutter which is fine but fiddly to set up. I just cut by hand mostly. Put marks every 10% on the root and tip to help keep you straight as you go. Practice the cut with the wire above the blank a few times to get a feel for how much one hand has to move relative to the other. You should end the cut with your body relaxed and in balance. It's always better to start off less balanced and end relaxed than the other way around.
It helps to count while you cut. You should hit every 10% mark at the roughly same interval.
RE. hand guided cutting. I have had some success cutting highly tapered wings by starting in the center and cutting out towards the ends. I'd make a plunge cut at the 30% and cut either forward or backward. The area where you plunge in always has a ridge from changing direction but I was cutting a slot for a spar with a router on that line so it didn't matter.
I've also built a gravity cutter which is fine but fiddly to set up. I just cut by hand mostly. Put marks every 10% on the root and tip to help keep you straight as you go. Practice the cut with the wire above the blank a few times to get a feel for how much one hand has to move relative to the other. You should end the cut with your body relaxed and in balance. It's always better to start off less balanced and end relaxed than the other way around.
It helps to count while you cut. You should hit every 10% mark at the roughly same interval.




#59

Hi Everyone
I am Winning, not quite there yet, I made a Red-Neck Gravity Feed for the Bow cutter, I hooked 2 - 12v car batteries together for 24V and used my 12/24 volt 30 amp DC motor speed controller, and I have great Control on the heat on the bow now, works like a Charm, I can set the heat perfectly now, My Bow, I found out is not Deep or wide enough, I am cutting foam at a angle, and I need a wider bow, the foam is 20" long, I made my bow 30" wide, but cutting at a angle, requires a wider bow, also, I did not make the bow deep enough, it hung up as I was making a Gravity cut, and it melted the foam a little more than it should have
I am Learning
I almost got a perfect cut, and might have if the bow did not bottom out on me
and hit the weight I was using to hold down the foam with, Live and learn, I need to get some more foam, I messed up the foam that I had Learning to hot wire it
I will succeed, If they can do it on You Tube, then I can Do It too
LOL, I used model air-plane wheels with the rubber wheel removed for the pulleys, Now how Red Neck is that
LOL, Off to lows tomorrow for some birch wood for a new bow and some 1/4" eye bolts for the wire, Take care and have fun, Chellie






Practice Makes perfect, I am Not Quite there yet, but Close
you can see where the bow hung up at on the trailing edge, and burnt into the foam towards the rear. I need to make a new Bow thats deeper and wider, so the silly thing does not get hung up and mess up my Foam











Practice Makes perfect, I am Not Quite there yet, but Close


Last edited by CHELLIE; 11-04-2014 at 08:52 AM.
#61

Hi Everyone
Finally Finally Finally Got My Hot wire Wing Cutter to work
Here are some pics, un retouched just the way they came out of the Shell, They need a little Light sanding and trimming, But I am, Very Happy the way they came out
trying to hot wire cut foam wings is not easy at all, Its right up there with with learning to fly RC Airplanes, after a Ton of Trial and Error
, I am happy with the results
here is what worked for me.
1. made 2 aluminium wing cord Patterns , used 3m 77 and small nails to hold the patterns to the foam. It Took me a Full Day to make those 1/8" thick Aluminium Patterns.
2. 24V, I used 2 car batteries in series hooked to a 12/24 Volt, 30 Amp DC motor speed controller with 20 gauge Ni Chrome wire.
3. Used a Tethered hot wire, one end is stationary and the other end follows the bigger wing cord pattern, inboard and outboard wing cord patterns were used,
4. Lots and Lots of Stubborn Determination to learn how to Hot wire Foam Wings
, I Win Again 









1. made 2 aluminium wing cord Patterns , used 3m 77 and small nails to hold the patterns to the foam. It Took me a Full Day to make those 1/8" thick Aluminium Patterns.
2. 24V, I used 2 car batteries in series hooked to a 12/24 Volt, 30 Amp DC motor speed controller with 20 gauge Ni Chrome wire.
3. Used a Tethered hot wire, one end is stationary and the other end follows the bigger wing cord pattern, inboard and outboard wing cord patterns were used,
4. Lots and Lots of Stubborn Determination to learn how to Hot wire Foam Wings



Last edited by CHELLIE; 11-20-2014 at 10:21 AM.
#63

Thank you Mech




#66
Super Contributor
Join Date: Mar 2011
Location: Fond du Lac, WI
Posts: 1,048

Extruded or expanded polystyrene will be much easier to work with.
Now that you can cut your own wings you'll realize the possibilities that skill gives you.
Now that you can cut your own wings you'll realize the possibilities that skill gives you.
Last edited by pmullen503; 11-21-2014 at 02:17 AM.
#73
#74

Ok Getting back to the build, Finally this Stupid Cold I have been Fighting off is getting better, Making some rough cuts on the foam to get the placement of everything and to get the CG, the ESC and lipo will be inside a vented cut out in the wing with a hatch cover to keep the airflow as clean as possible, I am using a 70mm edf, 60 amp esc and a 4 cell, 2200mah lipo, its getting there, I have to cut a slot for the wing brace, and esc and lipo, then, cover the wing with colored packing tape, the winglets and the middle skid will be the last things to be attached, hope to fly it this weekend if the weather is nice, Take care and have fun, Chellie

#75
Member
Join Date: Mar 2013
Posts: 121

First of all its good to see you cutting foam wings! They look great! Sorry you had to go to so much effort. Cutting foam wing should not be that difficult. I have been doing it for 37 years now. Maybe this link might help anyone trying to build there own cutter.
http://www.utahflyers.org/build-main...m-cutter-plans
http://www.utahflyers.org/build-main...m-cutter-plans