Did I mention BATTLE?!?!?!?! 
My club is having a fly-in next month. The "trouble-makers" in the group were all sitting around talking about how fun it would be to have 12-15 of us with planes we could fly like crazy and legitimately crash to smithereens in some aerial combat. Not some $90 EPP combat wing you buy online (and then would feel bad about smashing up), something CHEAP! I mean like $25-30 cheap. Something we can get together some night and all build together. Something we can go all-out and literally try to destroy by the time the weekend is up (some have even suggested shotguns if they're all not destroyed at the end).
So, after being volunteered by the rest of the group because I am the "mad (foam) scratch builder" I started putting together a parts list and a design.
Here's the requirements:
Build in 30-40 min.
Resilient enough to last through a few crashes, but not indestructible (we need to have a clear winner at the end).
Between $25-$30 TOTAL cost.
Fairly easy to fly. Most of these guys are pros, but we still don't want to have to worry about flight issues when we need to be concentrating on SMASHING INTO EVERYONE!!!!!!! AHHHHHHH!!!!!!
They added pylon racing to the list of things it needs to do, so that means it needs to be able to run on 2S and 3S with 5x3 props. 2S for combat, 3S for racing.
Here's the solution I came up with, as well as some of the revisions, pictures, and a video of one of the maidens:
Version 1. Majorly tail heavy. Super pitchy. Approx 210g total weight (everything onboard, inc. batteries). Crashed it nearly a dozen times with NO visible damage. REALLY need to make this more... uh... delicate? >.> This is the only time in my life I've had to try to make something more... crashable? Can't have everyone still in the game at the end because all the planes are indestructible, lol!
Version 3. (Version 2 never got built). Changed the design to try to move CG forward, and give more room for the prop. Also changed the airfoil, but I've since learned that on a wing with no tail AIRFOIL IS EVERYTHING. (So, back to the drawing board on that one). Also, removed all the paper from the inside of the wing surface and did away with the spars. This dropped the weight to 129g, which is surprisingly light, can't believe just removing the paper from the inside surface made that much difference. Anyway, once we put back in about 30g of nose weight on the front it flew really well. However, still really pitchy. The small tip-chord made it tip-stall as well, but not horribly. Possibly acceptable, but still want to tweak it.
Video of the maiden flight of v3 (after we adjusted for nose weight). Keep in mind, this is flying with a 2300kv multirotor motor, on a 2S 70C battery, with a 5x3 prop.
After this flight, I've gone back to v1 and made some adjustments to the airfoil, wing sweep, and servo and motor placement. Still attempting to get the weight as forward as possible to help with CG. I've done away with the creases in the foam and gone with a totally smooth airfoil (made possible by removing the paper on the inside of the wing surface). Included a really thin spar, not for structural integrity, but to help form the airfoil. I've also increased the sweep of the wings by 3/8", and reduced the tip-chord from v1 by about 3/16", but it's still a lot more than v2. Reduced the AoA (angle of attack) of the airfoil at the tips (with the forming spar) to increase "wash-out" to help with the wing-tip stalling issues. Made the fins a little tiny bit smaller to help with weight. Most importantly, moved the motor WAY forward into the wing to get it as "forward" as possible without sacrificing wing surface. I'll build it this week and maiden this weekend.
Here's a parts list I came up with to keep it as cheap as possible. Everyone is bringing batteries, and has radios, so those costs are not being included here:
$9.29 - Motor: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=61433
$6.15 - ESC: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=14870
$2.49 x 2 - Servo(s): http://www.hobbyking.com/hobbyking/store/__663__HXT500_6_2g_0_6kg_08sec_Micro_Servo.html
$10.49 - Receiver: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=46632
Total cost to build (flight ready): $31.91 ($1 for 1 sheet of DTFB included)
Here's all the versions of plans for anyone who may be interested. I'm currently building v5 and will be doing the maiden this weekend.
View attachment Plans_v1.pdf
View attachment Plans_v2.pdf
View attachment Plans_v3.pdf
View attachment Plans_v4.pdf
View attachment Plans_v5.pdf
Any suggestions anyone may have would be very appreciated! I'm super excited to be able to make a plane this cheap, and honestly if it flies really really well, this may very well be one of the best starter/trainer planes one could make. At this price point, and 3 chnl easy, this is accessible to even the broke-est noob out there. Hardest thing about this is the build. Maybe I'll make a build video.
My club is having a fly-in next month. The "trouble-makers" in the group were all sitting around talking about how fun it would be to have 12-15 of us with planes we could fly like crazy and legitimately crash to smithereens in some aerial combat. Not some $90 EPP combat wing you buy online (and then would feel bad about smashing up), something CHEAP! I mean like $25-30 cheap. Something we can get together some night and all build together. Something we can go all-out and literally try to destroy by the time the weekend is up (some have even suggested shotguns if they're all not destroyed at the end).
So, after being volunteered by the rest of the group because I am the "mad (foam) scratch builder" I started putting together a parts list and a design.
Here's the requirements:
Build in 30-40 min.
Resilient enough to last through a few crashes, but not indestructible (we need to have a clear winner at the end).
Between $25-$30 TOTAL cost.
Fairly easy to fly. Most of these guys are pros, but we still don't want to have to worry about flight issues when we need to be concentrating on SMASHING INTO EVERYONE!!!!!!! AHHHHHHH!!!!!!
They added pylon racing to the list of things it needs to do, so that means it needs to be able to run on 2S and 3S with 5x3 props. 2S for combat, 3S for racing.
Here's the solution I came up with, as well as some of the revisions, pictures, and a video of one of the maidens:
Version 1. Majorly tail heavy. Super pitchy. Approx 210g total weight (everything onboard, inc. batteries). Crashed it nearly a dozen times with NO visible damage. REALLY need to make this more... uh... delicate? >.> This is the only time in my life I've had to try to make something more... crashable? Can't have everyone still in the game at the end because all the planes are indestructible, lol!
Version 3. (Version 2 never got built). Changed the design to try to move CG forward, and give more room for the prop. Also changed the airfoil, but I've since learned that on a wing with no tail AIRFOIL IS EVERYTHING. (So, back to the drawing board on that one). Also, removed all the paper from the inside of the wing surface and did away with the spars. This dropped the weight to 129g, which is surprisingly light, can't believe just removing the paper from the inside surface made that much difference. Anyway, once we put back in about 30g of nose weight on the front it flew really well. However, still really pitchy. The small tip-chord made it tip-stall as well, but not horribly. Possibly acceptable, but still want to tweak it.
Video of the maiden flight of v3 (after we adjusted for nose weight). Keep in mind, this is flying with a 2300kv multirotor motor, on a 2S 70C battery, with a 5x3 prop.
After this flight, I've gone back to v1 and made some adjustments to the airfoil, wing sweep, and servo and motor placement. Still attempting to get the weight as forward as possible to help with CG. I've done away with the creases in the foam and gone with a totally smooth airfoil (made possible by removing the paper on the inside of the wing surface). Included a really thin spar, not for structural integrity, but to help form the airfoil. I've also increased the sweep of the wings by 3/8", and reduced the tip-chord from v1 by about 3/16", but it's still a lot more than v2. Reduced the AoA (angle of attack) of the airfoil at the tips (with the forming spar) to increase "wash-out" to help with the wing-tip stalling issues. Made the fins a little tiny bit smaller to help with weight. Most importantly, moved the motor WAY forward into the wing to get it as "forward" as possible without sacrificing wing surface. I'll build it this week and maiden this weekend.
Here's a parts list I came up with to keep it as cheap as possible. Everyone is bringing batteries, and has radios, so those costs are not being included here:
$9.29 - Motor: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=61433
$6.15 - ESC: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=14870
$2.49 x 2 - Servo(s): http://www.hobbyking.com/hobbyking/store/__663__HXT500_6_2g_0_6kg_08sec_Micro_Servo.html
$10.49 - Receiver: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=46632
Total cost to build (flight ready): $31.91 ($1 for 1 sheet of DTFB included)
Here's all the versions of plans for anyone who may be interested. I'm currently building v5 and will be doing the maiden this weekend.
View attachment Plans_v1.pdf
View attachment Plans_v2.pdf
View attachment Plans_v3.pdf
View attachment Plans_v4.pdf
View attachment Plans_v5.pdf
Any suggestions anyone may have would be very appreciated! I'm super excited to be able to make a plane this cheap, and honestly if it flies really really well, this may very well be one of the best starter/trainer planes one could make. At this price point, and 3 chnl easy, this is accessible to even the broke-est noob out there. Hardest thing about this is the build. Maybe I'll make a build video.
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