Posted by Tim McMahan on February 7, 2010 at 12:33pm
Since the twin booms seem to be the way to go, and I was wanting a payload plane anyway, I decided to build a twin boom. This is 100% scratchbuilt, even the wing. I gave it an RC only maiden flight this morning, and it flew like a dream. Highly stable. I do plan on adding rudders though, as I want to do some AP work, and require flat turns. It has a 60" KFm3 airfoil. The fuse is 5" square (about) on the outside and big enough on the inside to stick my arm in it. The nose has a removable EPP foam panel, I will replace with clear plastic for FPV/AP runs.
I am in the middle of my build I used 6mm depron on this one both on wings and body. My weight right now without electronics and motors is already at 780g I wonder if this is still ok with this model?
Graham Dyer > Don CapiliOctober 12, 2014 at 2:29am
27% (+/-3%) MAC is fine for this type of plane, it isn't very different in that respect to a more 'conventional' layout. Motor upthrust of about 2-4° is good practice as is 2-4° decalage (the horizontal angle between the wing and horizontal stabilizer - http://en.wikipedia.org/wiki/Decalage).
Nice airframe. Looks almost like one fuselage I am working on where I plan to use foam wings that are purchased as spares for other planes. Also, the fiberglass reinforcement is a clever idea. I was considering using very thin plywood as reinforcement but will likely use your idea instead. I am also working on a deltawing with Depron and KFm wings where I may employ some of the reinforcing ideas from you.
Some questions:
-What is the best online source of thin fiberglass material for wing and fuselage reinforcement? (In Norway where I am located theese things are often hard to find so I purchase most of my stuff from the US)
-How thick and wide is the drywall fiberglass tape you use? Is it a 3M product for example?
-What is a good online source of carbon fiber material for RC airplane building? Locally, the guys charge redicouluous prices.
Ok, I'm such dork. First off, I really like your mount idea with the aluminum tube. 2nd, we haven't exactly been using just "carbon fiber tubing". We've been using .260 CF tubing with a threaded hole in one end already. Arrow shafts!! they have an insert in one end to screw in different style arrowheads. The ones Jon used, which he was able to drill and pin are "full metal jacket" shafts, which are CF with an aluminum sleeve. splintering shouldn't be a problem on those, but they are hard to get.
I'm currently running this 2836-10, but plan to change it.
Dave Buckley, where do I begin!! THANK YOU, THANK YOU, THANK YOU!!! I'm not a smooth talker, so we'll leave it with all caps and repetition, LOL! Those models are AMAZING!!
I'm really glad you took a liking to the KF airfoils. Everyone should. I have built several flat plate and undercambered wings, but they cannot compare to the KF. I haven't flown much in the way of Clark Y airfoils, but that's because I scrathbuild most of what I fly. For scratchbuilding, NOTHING else can come close. 1- Ease of build. 2- lift. 3-stability. All 3 get very high ratings in my book, and I'm usually disappointed when I stray from the path of KF righteousness. LOL!
As for those boom mounts, my friend Jon has been working on some really cool ones. He may be willing to share, so I'll ask him to email you. :)
As for needing some modeling/CAD work, I can almost guarantee it!!
Here are Tiled .PDF's of the foam parts. These are not the full plans, just tiled patterns for the foam pieces. Paul will be working on full plans, but doesn't anticipate getting them done for a week or two, so here's something to get you flying. I'll answer any questions anyone might have about the build.
I already modded the V-stabs on the original by cutting off the bottom half. They were constantly banging the ground and needing repaired. I suggest cutting off, or using balsa.
ok, so im going to start my first uav. Is this a good plane to start with for me? i would go with easystar, but i wanna BUILD! not buy a premade plane. upload a pdf or something of it. thx.
So, I got my hands on 6 sheets of Depron80cmx125cmx3mm I think. Not entirely sure of the thickness. they are a bit bent at the corners, but I hope to make useable panels out of them to get started on my Scratchbuilt Twin Boom.
And hey Tim, its especially encouraging to see someont try something and really succeed at it. I look forward to seeing your plans, although I'm kinda playing in Sketchup to creat my own variation of your design. if something works though...
Oh, I got the Depron for a guy I work with, he is a Gaffer on films and they use this stuff to bounce and diffuse light on sets. He has a couple boxes of the stuff. Now if my life would settle down a bit so I can get started building.
Replies
HI Guys
I am in the middle of my build I used 6mm depron on this one both on wings and body. My weight right now without electronics and motors is already at 780g I wonder if this is still ok with this model?
Hi guys any info on the CG of this plane? Newbie builder here ;)
27% (+/-3%) MAC is fine for this type of plane, it isn't very different in that respect to a more 'conventional' layout. Motor upthrust of about 2-4° is good practice as is 2-4° decalage (the horizontal angle between the wing and horizontal stabilizer - http://en.wikipedia.org/wiki/Decalage).
Free CG app here: https://play.google.com/store/apps/details?id=appinventor.ai_graham... (shameless punt:))
Some questions:
-What is the best online source of thin fiberglass material for wing and fuselage reinforcement? (In Norway where I am located theese things are often hard to find so I purchase most of my stuff from the US)
-How thick and wide is the drywall fiberglass tape you use? Is it a 3M product for example?
-What is a good online source of carbon fiber material for RC airplane building? Locally, the guys charge redicouluous prices.
I'm currently running this 2836-10, but plan to change it.
I'm really glad you took a liking to the KF airfoils. Everyone should. I have built several flat plate and undercambered wings, but they cannot compare to the KF. I haven't flown much in the way of Clark Y airfoils, but that's because I scrathbuild most of what I fly. For scratchbuilding, NOTHING else can come close. 1- Ease of build. 2- lift. 3-stability. All 3 get very high ratings in my book, and I'm usually disappointed when I stray from the path of KF righteousness. LOL!
As for those boom mounts, my friend Jon has been working on some really cool ones. He may be willing to share, so I'll ask him to email you. :)
As for needing some modeling/CAD work, I can almost guarantee it!!
Thanks so much!
Tim
If I can help with CAD work/Blueprints/Renderings please let me know.
Your article led me to research the Kline-Fogelman airfoils, so thank you again for that.
I already modded the V-stabs on the original by cutting off the bottom half. They were constantly banging the ground and needing repaired. I suggest cutting off, or using balsa.
Tim
Boombox_p1_tiled.pdf
Boombox 2_p1_tiled.pdf
And hey Tim, its especially encouraging to see someont try something and really succeed at it. I look forward to seeing your plans, although I'm kinda playing in Sketchup to creat my own variation of your design. if something works though...
Oh, I got the Depron for a guy I work with, he is a Gaffer on films and they use this stuff to bounce and diffuse light on sets. He has a couple boxes of the stuff. Now if my life would settle down a bit so I can get started building.
Onward and upward...
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