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Apr 11, 2016, 12:38 PM
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Build Log

Sorta Scale full fuse B 2 Spirit Bomber sloper


Introduction

Ive been fascinated by the B 2 since getting into Electric R /C about 16 years ago. I have built many profile examples starting with GPWs sorta scale one to the extreme of carving an 8 foot w. s. full fuse model from Insulboard foam.
When Banana Hobby came out with a Blitz R/C scale EDF version I drooled over the super scale looks of it and almost purchased an airframe at one time.
Since learning slope soaring and becoming an advocate of that R /C skill a scale B 2 slope glider has been on my bucket list for some time.
Im not getting any younger.

So while I still have this burning ambition Im pursuing it to completion.

Im going to fly it with a 3 axis gyro Rx. The real B 2 has over 100 computers that help the pilot fly it so a gyro Rx is kind of a non brainer.
Im not going to clutter or un scale it with vertical stabilizers or fins. To maintain stability in the yaw axis Im going to use what glider guys call "CROW " on each wing controlled by the gyro Rx and the rudder input.
To do this I'll have 2 elevons on each wing , an outer one and an inner one. They will activate one up wards and one downwards to make each wing draggier independent of the other to cause the aircraft to rudder turn towards the wing with more drag.
Sounds good on paper huh.

My building materials will be 1/2 inch insulfoam, balsa , dowels, Readi Board foam and pool noodles . The pool noodles will simplify the building of the fuse and engine nacelles.
The w. s. is 80 inches and Im hoping to meet a 3 pound A.U.W.
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Apr 11, 2016, 12:41 PM
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Oh I have a dead line of Memorial Day week end to be able to take it to El Cajon scale slope non event.
Apr 11, 2016, 12:53 PM
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I've copied the top view plan form by tracing it from a 3 view off the computer screen and cut a starting profile from the half inch Insulfoam board foam. Then I came up with a dowel and CF tube spar and joiner structure so I can build each wing seperate then join the 2 wings at the end or at the field.
I've also used 4 foot dowels to strengthen the leading edge
Last edited by alpea 41; Apr 11, 2016 at 02:03 PM.
Apr 11, 2016, 01:06 PM
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This is not going to be a long drawn out build , my dead line is fast approaching and a fin less flying wing , painted black with a pregnant belly bulge that resembles a Spirit bomber seems doable in a relativly short time.

fin less" flying" wing does indicate a degree of optimism but nobody starts a build with failure as an option
Last edited by alpea 41; Apr 11, 2016 at 02:02 PM.
Apr 11, 2016, 02:06 PM
Still Screamin'!
rvincent's Avatar
Go Al!!
Apr 11, 2016, 02:18 PM
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alpea 41's Avatar
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thanks Bob.
Apr 11, 2016, 02:49 PM
Still Screamin'!
rvincent's Avatar
If theres anybody can make it fly, its you. Go for it. Can't wait to see the sloper version
Apr 11, 2016, 04:42 PM
Chino Renegade oh-gee, yo
Wrench66's Avatar
With all of the passion and experience you have this will be an awesome build Al......go for it!
Apr 11, 2016, 05:27 PM
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You guys are definately apprieciated
So moving along quickly. Got some span wise spars GG ed up . A quarter inch ply nose reinforcing plate. It always seems a foam wing takes abuse on its nose . And some yard stick tapered wing spars GG ed length of the airfoil. The only spars to add are wing tip elevon mounting stiffeners
The section between the wing spars will be my canopy formers and ragio box on the top side . And my bomb bay and bay door mount stringers from the bottom. So the compartment will be cut and designed to pass thru the wing.
Simple ,clever and adds strenth huh.
Might add a magnet attached verticle fin in the begging so as to allow experimentation with the crow yaw stabilization.
Next up the center fuse radio compartment and balsa wing tips. Then a few ribs and sheeting
Apr 11, 2016, 05:48 PM
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To get this thing C G ed at 33 % of the center line cord I know I'll have to make the tail end of it light
Apr 12, 2016, 11:37 PM
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Got really lucky today , went to dollar tree to get the readieboard, for sheeting and on the way there I thought, gee wouldn't it be nice if they still made the black sheets. And bam they had 4 sheets of black paper covered RAM readie board. Perfect , I bought all 4 , and removing the paper off one side causes it to curl in the right direction for my sheeting needs.
I also added the elevon hinge stiffening spars and cut away the elevon locations.
I'm going to make the control surfaces out of Dow blue square edge foam and sheet them with balsa. The Insulfoam is not ridged or strong enough.

I also glued up the sides of my central radio and bomb bay box. And it has balsa cleats to sheet too. I've decided to do the clamshell rudder halves as the scale one has. They will be configured 30 % open for flight then go to 100 % open as speed brakes for landing just as the real plane does. They are just too cool not to have them. I've also been watching lots of videos of the real plane and am quite happy with the plans in my head and how mine is looking and going to look .
Apr 13, 2016, 10:33 AM
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I've decided to simplify and glue up the wing halfs .Apparently I got a drop of GG Gorilla Glue on the forward span spar and it won't slide out of the CF tube. LOL
Here's an exaggerated view of my control surfaces in a Crow config.
And the inner elevon will be the yaw stabilizers, in an up wards deflection the wing that is yawning forward will present a greater surface area to the relative wind and will offer greater drag which will push that side back to perpendicular to the relative wind.
Apr 13, 2016, 10:49 AM
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It's guickly getting heavier. LOL
Im gonna revise my AUW guess and shoot for 5 pounds. On a big ass piece of foam like this it should still have a decent glide ratio
Apr 13, 2016, 03:06 PM
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hotlinercortt's Avatar
found your page!! looking good Al
Apr 13, 2016, 04:25 PM
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Why thank you Cort . I'm endeavoring to apply every freakin thing I've learned about making R C planes outta foam into this thing. Yet still move along swiftly so tune in often cuz it's moving quickly. And no telling what useless stuff u might learn from it.

From watching hours of video Ive discovered the belly has a more complicated profile then I first thought . But it is still much simpler than the top side so Ive begun to add former ribs to get the belly right . I'm using Dow 5/8ths thick Styrofoam Residential Sheathing Insulation cuz it will be easy to glue the covering sheathing too and I have a lot of it. I get it from the dumpster at the wife's work.
So heres a reference video for you followers to watch and make plans to build you one.
New B-2 Stealth Bomber Air-to-Air Footage [HD] (2 min 0 sec)


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