|Aug 27, 2006, 03:37 PM|
Fanfold TBF Avenger(2) 36inch
This is my second version for the TBF Avenger scratch build. The thread for the first version (TBF 30 inch) can be found here: http://www.rcgroups.com/forums/showthread.php?t=553610
This time around I wanted to design the plan digitally so I can make adjustments and also post it. This one has been scaled up to 36 inches and ended up being 37.5 inches when finished.
6mm Fanfold – combat style profile with horizontal crutch
4/40 type airfoil, strip ailerons
packing tape hinges, zip-tie control horns, bamboo skewer spars
4 ch Controls are R/E/A/T
Components have remained basically unchanged from the previous build:
1-Hitec HS-81 (aileron)
2-Hitec HS-55 (rudder & elevator)
GWS 350c ‘D’ gear (11X4.7, 11X8 Slow Flyer props)
9.6v 720Mah niMh
Berg Microstamp 4L reciever
FMA mini-30 ESC
This time around I wanted to go very light using just the single thickness profile. I built it purposely light to see if there are any stress areas that need stiffening. The only thing I had to do was add foam doublers to the lower nose portion to aid in rough landings. No landing gear this time for the maiden flights.
The stab sits on top of the crutch instead of sitting higher on the vertical fin (TBF30). Since it is meant for combat, I wanted it to be strong and straightfoward. Outlines are still basically scale except for adding some wing cord to make up for the bend in the airfoil.
I decided to place the wing on top of the crutch secured to three base ribs. These made it very strong and maximized the wing area. It also provided an excellent compartment to hide away servo wires and the reciever. There’s plenty of room to put the ESC in the other side for the final version.
Wing stiffener is two bamboo skewers which have worked fine, but allow a lot of flex under high load.
The pictures show the original airfoil, I’ve changed it slightly to resemble a more mellow 4/40 type. I slid the wing all the way to the rear to build in about 2 degrees incidence.
Rudder is apparent in flight, but it is more an option and not necessary. This version flies wonderful and very scale-like. It’s not a 3-D flyer, but very manuverable for combat or fun flying. I’ve flown it in 15-20mph winds with excellent performance.
I'm sure the gear/prop combo could be setup better (I just use what I have).
I'd also like to see how it flies with a newer CDmotor and LiPo's.
The single aileron servo (HS-81) isn’t to my liking. I would change this to two smaller ones placed sideways in the wing ribs. The finished plan will reflect this change.
So here are the build pics. I’ll post a .pdf of the plan once I update it with a couple improvements:
ImagesView all Images in thread
|Aug 27, 2006, 09:36 PM|
TBF 36 Plan
Thank you WarrrEagle. Im trying real hard to keep it simple and clean.
Here's my first attempt at producing the plan in .pdf format. I was unsuccessful in getting it to tile without all the tiles becoming HUGE.
I've also included a quickie cockpit image for both sides. Not perfect, but I can't tell in flight.
Flight update** 20 flights and not one broken prop!
|Aug 27, 2006, 09:41 PM|
I just realized that the center rib was included only because I wanted a solid anchor for the central aileron servo. If you build it with two smaller servos on the outside ribs, you won't need the central one at all.
Unless I find out that the central rib also helps with the wing loads at high G. Hmmmm.
|Aug 28, 2006, 08:51 AM|
Thanks for posting. It looks great. Now my list of planes to build grows even larger.
Let JAM (http://www.rcgroups.com/forums/member.php?u=34464) know so he can add your work to the sticky list of plans.
I just noticed you run the motor off to the side instead of being centered on the stick line. Does this eliminate the need for right thrust? It looks like this leaves the front a bit stronger than cutting things out, and a bit faster build as well. This seems like a good idea. How does it affect flight?
|Aug 28, 2006, 12:07 PM|
Thank you guys very much.
I found the side mounted EPS idea several places online. I know there are a couple of combat planes out there that use this mounting. It made sense to keep the cutting simple and keep the motor out of the danger zone.
No, it doesn't affect flight performance at all. It actually is just like the 'No-Cal' rubber profiles with the motor stick mounted on the right side.
I did build a bit of downthrust into it. It flies very stable and dead straight at about 1/4 throttle.
Yesterday, I tried to push the envelope a little. I was able to fly it inverted, snap rolls, square loop, and even a cheap attempt at knife edging...
It was more like a level slip, but I'm extremely satisfied with the performance. And as of yet, no stress cracks or unwanted torque flex.
Now to attach the ribbon and find some competition.
|Aug 30, 2006, 08:22 PM|
GPW~ I've tried to get the plans into a tiled pdf with no success. I drew the TBF up in Adobe Illustrator 9 and cannot seem to get a decent tiling. The best I got was correct tiles, but each was the size of the full plan!!!
I tried exporting to Turbo CAD, posteriza, and a full Acrobat. I can't get a decent tile set.
I was able to print in multi page option from Illustrator, but no way to save them to add to a pdf file. I'm stumped!
Im still hoping for a reply to the RastaPrint thread, but haven't heard anything on that.
|Aug 31, 2006, 07:11 AM|
If you can export them as an image file, Paint that comes with windows can print them tiled. There's a free program called 'PDF Creator' that installs a fake 'printer' that actually saves whatever is printed to it to a PDF file. I've had good luck with this method. The only catch is that it does not leave a printed border around the margin of each tiled page.
I haven't looked at this yet in detail, but it is on the list to evaluate as it does a lot of things with printers:
I can create the tiled PDF over the weekend if need be.
|Aug 31, 2006, 11:26 AM|
Thanks for the suggestion kdahlhaus. I don't have trouble printing them tiled, but have trouble getting a correctly scaled tiled file. But I'll look into your method since an image file(s) is all that is needed to share the pdf.
Another tile thread popped up yesterday that mentioned a pdf writer "Ghostscript". I can try that too.
In the middle of the night, I thought of maybe printing the job to file since the print job worked fine. I could try to add those (eps) files to a pdf.
I want to make a change to the plan today to show where I made a doubler for the nose section. It helps with rough landings.
Another improvement may be a leading edge wing panel that extends a little past the outboard rib. I had one cartwheel landing that cracked the wing right where it attaches to the rib. Really, even a peice of stiff artboard would help strengthen that joint and add a good anchor for the landing gear.
I appreciate any help offered. If you can tile these with little effort, please do and post here.
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