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.
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).
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.
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.
Thanks, Graham. I couldn't do my set up quite as nice as yours, but I did stare long and hard trying to figure out how I could. I will likely do something similar in the future. I also used your pics to help me mount my IR sensor. :)
I flew the Boom Box yesterday again (rc only), but with a handheld GPS on board for tracklogging. It stay airborne for 30 minutes, and tracked 10.4 miles! The Ardupilot is getting a LOT closer. I can't wait!
I just sold my Predator and have been looking for a kit, but this is ideal for what I want to do and its all DIY. Looks great, hope you don't mind if I use your design.
Ok, part two of the video is up. Its a bit shakier than part 1, as the wind was picking up the whole time. You can really tell when I fly by the windsock.
All the Ardupilot parts are ordered, so now its just a matter of time. :) I can't wait. The plans are getting much closer by the way.
Tend to agree with Gary. I did some more test on my Maxi Swift this weekend in fairly strong winds and all I can say is WOW! even with stabilization switched off I could easily control this gem full blast to hover landings.
Replies
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:))
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
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...
I flew the Boom Box yesterday again (rc only), but with a handheld GPS on board for tracklogging. It stay airborne for 30 minutes, and tracked 10.4 miles! The Ardupilot is getting a LOT closer. I can't wait!
I just sold my Predator and have been looking for a kit, but this is ideal for what I want to do and its all DIY. Looks great, hope you don't mind if I use your design.
Look forward to seeing future updates.
Thanks Tim.
All the Ardupilot parts are ordered, so now its just a matter of time. :) I can't wait. The plans are getting much closer by the way.
-
1
-
2
of 2 Next