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Old Jun 22, 2012, 09:44 AM
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When I was about 13 I discovered duct tape. I was a firm believer that you could fix anything and everything with it. And everyone should use it as much as possible, whenever possible.
Now, 10 years later I discovered how well hot glue works with foam. Needless to say - I'm a firm believer that you could use it on anything and everything

What I mean to say is that I'm probably the worst person to ask abour adhesives. I have eposy, gorilla glue, CA's and accelerators laying around and I'm not using any of them. Epoxy might work with cards and foam, doubt about the gorilla glue though. 99c store next to my house is always out of stock on glue sticks, because I buy them all

Also to make life easier and to ensure stronger connection between plastic cards and foam you could do something like on the pic attached. You can cut and push and bend in place small fins that can be stabbed right through the foam. That should give cards a better grip


In other news - I built a really quick (2-3hrs) Kfm2 + armin wing. 30" span, 2200kv micro jet v3 motor, LEDs placed inside the airfoil, wooden dowels for reinforcement. ~400g with 1.3a battery. Pics and maiden next week, going camping for 2 days
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Old Jun 22, 2012, 12:58 PM
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good idea for the gift card cutouts.

Low and slow - i really like having the fuse under the wing. it adds a bit of weight but it gives you a nice spot to grip to throw the plane. I haven't broken a prop yet doing belly landings.
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Old Jun 22, 2012, 08:02 PM
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Hey Nieder2 what's the wingspan on yours? Mine is 40 wasn't sure I remember what yours was. I like the way your plane flies that suits me fine. I'm not interested in speed so much as easy to fly and stable. And I have the hand launch down with my other two planes. I'll be smart and take it up to my dad's hay field and fly. I don't have the problems there.

This plane will also be flown with my new radio so I don't know how to program it yet I'll probably fly it seat of my pants till I learn what expo and rates is. I have no idea. Oh the radio is a turnigy 9x if you or anyone can shed some light on learning about this that would be cool. I'm not worried about the weight everything except the receiver and one servo added up to just under 14 ounces. I still need to add the elevons and tips so I think 15 or so tops. My other plane is 24 and it flies like a lumber truck. It might be changed to a pod and boom design I like those too.
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Old Jun 23, 2012, 06:16 AM
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If you've got 2" elevons on a 40" wing you will want to limit the throws and add some expo. Learning how to do this on your radio is better than having to build another airframe. On mine I ended up decreasing the throws to about 50% and used 40% expo. 3/8-1/2" throws should be more than adequate. You may want to decrease you elevator throw even more since these flying wings are very sensitive to pitch change.

Are you using the stock 9x firmware or er9x? I have the same radio, but I immediately installed er9x immediately. If you have er9x I can help. Otherwise maybe someone else can chime in.
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Old Jun 23, 2012, 07:40 PM
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Here is that 30" KFm2 wing I briefly mentioned earlier.
GraysonHobby MicroJet v3 will be spinning a 6x4 prop.
There is a reason I didn't run LED all the way to the end or in a better pattern, I pulled a chunk of them from another plane and didn't feel like cutting and soldering them all over again, so I used what I had.
Now all I need is to get some mosquito spray and I can fly all night
(give that maiden tonight will be successful)
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Old Jun 25, 2012, 09:48 AM
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Took it for a flight on Saturday. Looks great in the air at night. It was a super quiet night, but I think I will add vertical stabilizers for less calm days. It might be a little too zippy for night flying with that 2200kv motor, but it's light and KFm2 slows it down as soon as I throttle down.
One thing that I might do is add extra tape on the bottom to block off some of the LEDs from showing through, so I can tell better which side is up and down.
All in all it met and exceeded all of my expectations and I had people coming up to me asking where to buy one. Color tape makes it look so pro Next I'll try building a piper with armin wing and cover it with yellow tape, curious to see how many people will think it's a kit.


Also I edited original post to contain links to useful visual info in this thread that others have posted. Should make life easier for new comers
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Old Jun 25, 2012, 12:12 PM
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Quote:
Originally Posted by Low and Slow View Post
Hey Nieder2 what's the wingspan on yours? Mine is 40 wasn't sure I remember what yours was. I like the way your plane flies that suits me fine. I'm not interested in speed so much as easy to fly and stable. And I have the hand launch down with my other two planes. I'll be smart and take it up to my dad's hay field and fly. I don't have the problems there.

This plane will also be flown with my new radio so I don't know how to program it yet I'll probably fly it seat of my pants till I learn what expo and rates is. I have no idea. Oh the radio is a turnigy 9x if you or anyone can shed some light on learning about this that would be cool. I'm not worried about the weight everything except the receiver and one servo added up to just under 14 ounces. I still need to add the elevons and tips so I think 15 or so tops. My other plane is 24 and it flies like a lumber truck. It might be changed to a pod and boom design I like those too.
With the winglets mine is ~45". Its definitely a nice stable platform.

I flashed my 9x to er9x as well right after i got it so i'm no help with the stock firmware setup but there should be plenty of guides if you search here or youtube. I wouldn't try to maiden at full rates otherwise you're likely to overcorrect. The only time i fly at full rates is when i'm trying some aerobatics.
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Old Jun 27, 2012, 10:03 AM
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My new 40" wing is well under way. I am hoping to break 100mph with it using a 2836 3500kv motor from RCTimer, a 50amp ESC and 4.1x4.1, 4.5x4.5 or 4.75x4.75 prop (depending on amp draw).

Below are some photos of the build so far. I still need to install the electronics, and cover/attach the winglets/elevons, but the AUW should be around 20oz with a 7oz 3s 2200mah battery. I left the paper on the outside of the wing this time, but still removed it from the inside. My previous 40" wing was 17.5oz and it had a smaller motor, ESC, battery, and all the paper removed.

I'm still on the fence with the Great Stuff leading edge, but it would reinforce the wing significantly. I'm tempted to see if it can handle the speed as is, but if the nose hits the ground at 50+mph, the airframe will be done.
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Old Jul 22, 2012, 09:29 PM
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Tim,

I'm in the process of collecting parts for a new FPV rig and want to make it a wing with fuse (like my current plane i've posted here) but i want to make a larger wingspan to hold the extra weight of LRS, Vid Tx, OSD, more batteries, etc and keep the nice stable characteristics i'm used to with my 45" WS version.

I thought about taping and glueing multiple sheets of $tree board together to create a larger "sheet" then fold like the typical Armin airfoil, but remembered you'd done the 2 piece. I'm thinking 55-60" like the one your dad sent towards earth a little too fast

Could you give any feedback on disadvantages of a two piece (top and bottom as separate pieces) wing half vs a folded wing in the typical Armin style?
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Old Jul 23, 2012, 09:26 AM
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Originally Posted by nieder2 View Post
Tim,

I'm in the process of collecting parts for a new FPV rig and want to make it a wing with fuse (like my current plane i've posted here) but i want to make a larger wingspan to hold the extra weight of LRS, Vid Tx, OSD, more batteries, etc and keep the nice stable characteristics i'm used to with my 45" WS version.

I thought about taping and glueing multiple sheets of $tree board together to create a larger "sheet" then fold like the typical Armin airfoil, but remembered you'd done the 2 piece. I'm thinking 55-60" like the one your dad sent towards earth a little too fast

Could you give any feedback on disadvantages of a two piece (top and bottom as separate pieces) wing half vs a folded wing in the typical Armin style?


I've experimented with 60" ws for the sake of building exercise. I'd say 30" per wing with $tree foam is about the limit, It's ok to glue top and bottom halves from separate sheets of foam, but even then you're limited as to how much sweep you can get. However I would not try to glue 2 pieces of foam together at the edge just to get a 40x30 sheet for instance, I feel like folding that gigantic piece of foam with a glue seem in it would be a pain in the rear, also at that scale, thickness and rigidity of $tree might not be enough.
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Old Jul 23, 2012, 09:44 AM
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Nieder2,
The 55" wing I built was done to make the largest size wing possible out of Dollar Tree foamboard. As you have seen each wing quarter requires a full sheet. I'm sure the leading edge isn't quite as strong as if it were a folded single piece, but I it ended up with 4 layer of tape on it. Also, I removed all the paper from the board and leaving this on the outside would have helped with strength

I used 3m Extreme Packing Tape to initially join the two wing quarters together. Then I folded them back and sanded a bevel into the internal leading edge to relieve a bit of the tension. This worked out well when folding them into the airfoil shape

The weakness of that size wing was the nose. Since room needs to be made in the center of the wing for the battery and electronics, this leads to a weak point. Compound that with a larger, and therefore heavier, airframe, and you see the issue. Doing the Great Stuff trick to the leading edge and leaving paper on the outer skin would have made it bulletproof.

All that being said, your design won't have these issues, because of the under-slung fuselage. You can extend the foam former/spar all the way to the center of wing, since you won't be needing all that room for electronics. Doing that will also help to make the nose stronger, but the nose won't be the first point of impact in your design anyway.

If you use my template for the 55" wing, and ignore the cutout for the motor, you will be looking at 700 sq in of wing area (less if you want a flat bottom airfoil), including the elevons. Remember that my designs form a symmetrical airfoil, so if you want a flat bottom you will need to shorten the wing chord on the bottom wing quarters (or just cut off the excess after gluing the top down), since you can't make the top quarters any larger.

For more reinforcement, you could use three 32" carbon arrow shafts. Gorilla Glue one to each of the inside of the leading edges and the then one across the CG line. I think this would be overkill, but it would be lightweight option for a really stiff wing.
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Old Jul 23, 2012, 10:52 AM
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Foam Flying Wings

Bought a kit for a smallish flying wing not long ago from a guy that cuts them out from 1/4" Blu-Core fan fold. He has a CNC machine and uses many of the same techniques you do, but taping is an option. Very straight forward build after the foam is folded to make the leading edge. He builds them for combat and speed records. One game they play at their field is to buzz the landing strip, turn around, buzz it again until the battery pack is exhausted. To win you have to have the highest speed and the most laps.
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Old Jul 23, 2012, 11:16 AM
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Quote:
Originally Posted by templton89 View Post
I've experimented with 60" ws for the sake of building exercise. I'd say 30" per wing with $tree foam is about the limit, It's ok to glue top and bottom halves from separate sheets of foam, but even then you're limited as to how much sweep you can get. However I would not try to glue 2 pieces of foam together at the edge just to get a 40x30 sheet for instance, I feel like folding that gigantic piece of foam with a glue seem in it would be a pain in the rear, also at that scale, thickness and rigidity of $tree might not be enough.
Sweep becomes less of an issue as you increase the wingspan. The purpose of the swept wing is to move the desired CG location rearward. In smaller airframes you have less internal room to move the battery to adjust the CG, so swept angles like 35 degrees in your ~40" design are necessary (I have 26" version now too). However, when I upped the wingspan to 55" I lowered the sweep to 28 degrees. The added benefit of this, is that the airframe takes up significantly less room.

In Nieder2's case, where he plans to use a fuselage, wing sweep will be even less of an issue. This is because the fuselage will most likely extend fore and aft of the root chord, and give him lots of options for CG.

I'd like to revisit the 55" for FPV in the future. The biggest reason I haven't built another is that it requires a lot of tape to cover the wing.

Check out letmeplaymystrat's YouTube channel, because he has been experimenting with a 52" Zagnuts wing (essentially the same thing we are doing here) for FPV. The first video he did on it used the under-slung fuselage, but he ended up ditching it in the end.
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Old Jul 23, 2012, 12:51 PM
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Originally Posted by TimJC View Post
Sweep becomes less of an issue as you increase the wingspan. The purpose of the swept wing is to move the desired CG location rearward. In smaller airframes you have less internal room to move the battery to adjust the CG, so swept angles like 35 degrees in your ~40" design are necessary (I have 26" version now too). However, when I upped the wingspan to 55" I lowered the sweep to 28 degrees. The added benefit of this, is that the airframe takes up significantly less room.

In Nieder2's case, where he plans to use a fuselage, wing sweep will be even less of an issue. This is because the fuselage will most likely extend fore and aft of the root chord, and give him lots of options for CG.

I'd like to revisit the 55" for FPV in the future. The biggest reason I haven't built another is that it requires a lot of tape to cover the wing.

Check out letmeplaymystrat's YouTube channel, because he has been experimenting with a 52" Zagnuts wing (essentially the same thing we are doing here) for FPV. The first video he did on it used the under-slung fuselage, but he ended up ditching it in the end.
Thanks to both of you for the responses. I have seen and subscribed to "letmeplaymystrat". his wing is really nice. I might look at decreasing the sweep a little. I'll work on some CAD layouts.

My rough plan is to use the fuse for camera pan/tilt, batteries, ESC, current sensor, and motor mounting. The OSD would go in a small compartment in the center of the wing and I'd put the Vtx in one wing half and the LRS Rx in the other. I'm sold on the great stuff foam and will put that in front of the wing former again. And I think 3 spars in an A frame should be plenty rigid.
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Old Jul 23, 2012, 01:45 PM
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I'm still not giving up on idea of a modular wing, maybe I'll try a 60" one that comes apart in near future. Thinking what kind of power plant I need for that, probably something with under 1000kv and 10-11" prop
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