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Need help attaching the wings

eagle4

New member
#1
Hey guys, I'm thinking of embarking on my first scratchbuild that doesn't involve plans or a detailed instructional video. I'm going to make the Burnelli UB-14

UB-14-Newark.jpg burnelli-ub14-side.jpg ub14_v6.jpg

Anyway, I'm trying to work out how i'm going to attach the wings to the fuselage. As the fuselage has a large wing cross section I'm thinking of making the wing in the 2 halves, and join it together with a carbon arrow shaft with a space wide enough for the fuselage, so i can just drop it into the fuselage. and lower a foam flap over the top of the fuselage to continue with the body's aerofoil shape. I'm not sure if this is the ideal way to go about it. also, not sure how i'll go about attaching the wing either. as the carbon arrow shaft will be inside the plane it'll be hard to mount with rubber bands or something like that.

Do any of you have any ideas on how i could go about this mammoth project?

Dave

Edit: I'm thinking of making this with about a 1 metre wingspan
 
Last edited:

Liemavick

Member
Mentor
#3
Judging by the photos I'd build the fuselage and attach the 2 wings to it's sides. Perhaps something like the FT 3D design only flush with the top of the fuselage to give the appearance of a single wing. Just thinking out loud :)
 

CrashRecovery

I'm a care bear...Really?
Mentor
#4
Could always make it a two piece plane. Wings and then fuse. Secure the wings like the ft ol fogey. A couple large rubber bands
 

pgerts

Old age member
Mentor
#5
Hey guys,.... this mammoth project .... with about a 1 metre wingspan
I am really looking forward to see your progress. There seems to be some versions of the Burnelli.
A scale project it always fun and there seems to be enough information and sketches on the net to make a really nice plane.
It seems like a narrow space between the motors and the propellers seems to be limited to 7" but that is OK with ~19 gram motors on 3 cells.
I believe that the hard point might be to get the rudders and elevators to move nice. The boom construktion dont seem to allow other than push pull wires routed in tiny tubes.

I am always impressed when looking at the local championship in scale models. It is truly a mammoth project you are going to.
 

eagle4

New member
#6
from my rough mesaurements the fuselage will be about 20cm wide, so that should leave about 16cm between each prop. Whats a 19 gram motor? I've only known motors based upon their kv rating.

As it'll be tough getting controll up to the rudders, I'm contemplating just making this a bank and yank. Although I'm currently building my first plane to have a rudder right now, so maybe i'll find it really useful.

as for the push pull routed wires for the booms, i was thinking of just mounting the servo on the rear tail plane, unless you reckon having the servo mounted in the fuselage and just the pushrod extending up the boom would be better.

As for mounting the wing, I'm thinking I can install a carbon tube into the fuselage and have wooden dowel rods in the wings than can plug into the carbon tube, then anchor them with a pin or something. and make use of the wing struts to help give some strength and rigidity.

in your opinion, would you say that having the sides of the fuselage made from dollar tree foam be strong enough? or perhaps i should make them out of something much stronger like light ply wood or something?

Dave
 

pgerts

Old age member
Mentor
#7
20 cm is what i measured roughly for a 100 cm wing span, giving that a 20cm (8") prop be in the danger zone to hit each other.
That size of scale plane is OK if you manage to build it with about 600-800 grams total weight for an outdoor model.
2 motors with a power of 80-100W each would fit the plane and the weight of such a motor is normally in the 20 gram range.
This http://www.hobbyking.com/hobbyking/store/__6547__TURNIGY_2204_14T_19g_Outrunner.html motors with 10 amp ESCs might be something useful on 3 cells.

Rudder might not be important as you can use the motors mixed with rudder input from the radio to give "the rudder" turn.
Yes a 1,5-2 mm carbon rod will be fine as pushrod for the elevator. Mounting the servo in the narrow boom will certainly destro the scale look.

Do you really need to make the wing in parts? It is only 100 cm span. Yes, you can make it the way you say with CF tube and wooden dowel.

I would have done that plane in balsa with spruce. The size do not tell for any need for ply other than 1 mm for the motor mount.
Any foam will be harder to get a nice scale look with but i might be wrong. There is a really nice scale build in the january number of RCM&E if you can find that number in your library.