So a while back I designed my first wing ever. I called it the Albatross because relative to my other planes at the time it had a fairly large wingspan, but not large enough to warrant the name Condor. Basically what I did is drew a leading edge spanning 2 sheets of foam, folded it over, glued the wings together and called it a day. The wing was so flimsy that I later had to glue a plywood spar where the trailing edge of the KFm step was. At that point the wing was flyable, and it flew rather well. However as you can probably tell the wing was still pretty flimsy and it was very unstable on the pitch due to the pretty high aspect ratio and the complete absence of any sweep other than a tapered leading edge. I eventually decommissioned it and it sat around for a few months.
Fast forward about 5 months (about a week ago from when I posted this) I was watching some old flite test episodes to take in the glory that once was and I came across the RV jet episode. This really inspired me to make another wing so I could have my own scratch built "RV jet". Later that day I got some foam and at about 10pm on the same day that I watched that episode I had a mostly completed Albatross (v2 I guess?). I think that I have fixed most of the issues with the old Albatross. Of course I added sweep to the back so now it looks like a legitimate wing and should be a whole lot more stable on the pitch axis. I also fixed the flimsyness of the wing by building the plywood spar into the design of the airfoil instead of just slapping it on.
(TL;DR, when the wing bends it's trying to pull the surfaces of the wing apart, and it isn't really able to do that so it keeps it's shape)
I'm no material engineer so I'm not 100% sure this is why the wing is so rigid, but I created the airfoil this way because I thought that having a gap between the top and bottom of the airfoil would work in the same way as why foamboard is so rigid. If you delaminate some foamboard the depron itself is very flimsy, but when its laminated the paper prevents it from bending. If the middle of the foam is where it bends, then just the foam bending is no problem because its a naturally flexible material. but if you add the paper at an offset from the center of bending(?) it will try to pull the paper apart which doesn't work to well. This property is what gives the foamboard it's rigidity, and I believe the same concept is at play in my wing. along with the bit of rigidity that comes with the spar, the foam sheets are trying to be bent and pulled but do a pretty good job at keeping their shape, and this makes the wing rigid.
Another thing that I incorporated with this project was trying to learn how to use Inventor (CAD software) to create plans. I spent a few hours trying and learning, and eventually I figured most of it out. I already had some experience with sketching for 3d modeling so I knew most of the basics, I just had to figure out the process of making the plans. I exported the plans to PDF and cropped them down to size. Ill include the files so you can check them out or even build your own Albatross if you want. The problem with this is that the format for the inventor drawing was about the size of a sheet of foam, but I couldn't figure out how to split up the one big PDF into a bunch of smaller PDF files, the only way I know to print out the plans is to print them through Adobe Acrobat Reader, and print the files on the poster setting (this automatically splices up the PDF into a bunch of 8x11.5 sheets). Also, I included a materials list and listed the electronics that I used, but I did not include instructions on how to actually build it. If people want to actually build their own Albatross I will probably write instructions on how to make one or I might make one for my friend and film the process.
I haven't actually maidened it yet (I hope to tomorrow) but I will post updates on how it goes. I plan to eventually put FPV gear on this and maybe figure out a system for mounting batteries in parallel to get super long flight times with it.
P.S. the materials list on the plans is a prime example of why proofreading exists.
Fast forward about 5 months (about a week ago from when I posted this) I was watching some old flite test episodes to take in the glory that once was and I came across the RV jet episode. This really inspired me to make another wing so I could have my own scratch built "RV jet". Later that day I got some foam and at about 10pm on the same day that I watched that episode I had a mostly completed Albatross (v2 I guess?). I think that I have fixed most of the issues with the old Albatross. Of course I added sweep to the back so now it looks like a legitimate wing and should be a whole lot more stable on the pitch axis. I also fixed the flimsyness of the wing by building the plywood spar into the design of the airfoil instead of just slapping it on.
(TL;DR, when the wing bends it's trying to pull the surfaces of the wing apart, and it isn't really able to do that so it keeps it's shape)
I'm no material engineer so I'm not 100% sure this is why the wing is so rigid, but I created the airfoil this way because I thought that having a gap between the top and bottom of the airfoil would work in the same way as why foamboard is so rigid. If you delaminate some foamboard the depron itself is very flimsy, but when its laminated the paper prevents it from bending. If the middle of the foam is where it bends, then just the foam bending is no problem because its a naturally flexible material. but if you add the paper at an offset from the center of bending(?) it will try to pull the paper apart which doesn't work to well. This property is what gives the foamboard it's rigidity, and I believe the same concept is at play in my wing. along with the bit of rigidity that comes with the spar, the foam sheets are trying to be bent and pulled but do a pretty good job at keeping their shape, and this makes the wing rigid.
Another thing that I incorporated with this project was trying to learn how to use Inventor (CAD software) to create plans. I spent a few hours trying and learning, and eventually I figured most of it out. I already had some experience with sketching for 3d modeling so I knew most of the basics, I just had to figure out the process of making the plans. I exported the plans to PDF and cropped them down to size. Ill include the files so you can check them out or even build your own Albatross if you want. The problem with this is that the format for the inventor drawing was about the size of a sheet of foam, but I couldn't figure out how to split up the one big PDF into a bunch of smaller PDF files, the only way I know to print out the plans is to print them through Adobe Acrobat Reader, and print the files on the poster setting (this automatically splices up the PDF into a bunch of 8x11.5 sheets). Also, I included a materials list and listed the electronics that I used, but I did not include instructions on how to actually build it. If people want to actually build their own Albatross I will probably write instructions on how to make one or I might make one for my friend and film the process.
I haven't actually maidened it yet (I hope to tomorrow) but I will post updates on how it goes. I plan to eventually put FPV gear on this and maybe figure out a system for mounting batteries in parallel to get super long flight times with it.
P.S. the materials list on the plans is a prime example of why proofreading exists.
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