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Foamie B-1 Bomber #3

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15 Responses to “Foamie B-1 Bomber #3”

  1. Patrieck says:

    Nice to see it flying Bob!

    Just one question: You have it balanced out with the wings swept back…how does it fly with the wings swept forward? Do you have to change the balance then?

    Keep up the good work!

  2. Sid Gates says:

    I usually set my movie camera on fixed focus for taping model flying. I think you will maintain a sharper image.

  3. Jim J says:

    The foamy helps with the basic CG issue, as well as other issues when you start sweeping the wings back and forward. However, the foamy leaves out the landing gear which should be taken into account along with wing position in the CG equation.

  4. Richard says:

    BOB!!! I have a large vacant spot in my Bob-O-Schedule! Where’s more vids of the “BIG B1”?

  5. catman says:

    Generally speaking, I can see the value in building the foamie and flying it around to see how the configuration is going to work, but it seems to me that a little foamie with a motor and a prop on its tail really flies nothing at all like a 200 or 300 lb whopper with four turbines with different thrust lines. Why reinvent the wheel? There already are swing-wing F-14 models out there, including a small one by Nitro, that have solved the shifting CG problem. Admittedly, the moments and aerodynamics on an F-14 are different from those of a B-1, but the basics are the same. I don’t think this issue is going to be solved aerodynamically on the big model — I think it’s going to require moving some weight back and forth in the fuselage as the wings swing to get it to stay in CG. And don’t forget that all the best laid plans will change as all that fuel ahead of the wing burns down.

  6. Matthew says:

    ^well said.

  7. Jim J, The landing gear has no effect. It retracks straight up.
    Catman, The foamy has already helped alot ! We found out that the foamy has the same thrust line as the big boy! The CG doesn’t move as much as the full scale but it does move. Were tring to figure out the best way to correct the problem. So the Foamy is doing it’s job !

  8. Ed Zurek says:

    Maybe Bob took a much needed vacation!!

  9. ron says:

    hi guys
    how about a weight like they use in gaint scale trains on a rail that would move back and forth with the help of a servo for the cg, wheels up or wheels down, wings out ,wings sweeped love your work guys keep it up ron

  10. Richard says:

    How about, both wings working off one servo utilizing a worm gear with a weight mounted on the screw gear that moves forward and aft with the direction of the wings and cg movement?

  11. mike w says:

    Ron, i already suggested that idea to him in a earlier comment, maybe he can try it on the foamy and see if it if doable or not?????
    bob i’m going thru withdraws here!!!!!

  12. Jim J says:

    Butch Sickels: thanks for the reply!
    Glad the gear sucks straight up and keep up the work with the foamy. Catman’s F-14 points on CG are good ones and I also feel as he does that moving weight in the fuse as the wing configuration changes will be needed, but wring as much basic information you can from that silly foamy. This is turning into a very interesting aerodynamic think tank.

  13. Jim J, we don’t have the room for a sliding weight. I know that sounds crazy but there is a bombay in front of the wing spar. We are palying with the idea of pumping fuel. The pump will be wired with the wing swing actuator, so it will pump as long as the wing is moving. We will have to test it and see how much weight we have to move and how fast we can pump the fuel. Hey it works on paper ! Ha ! Butch

  14. Jim J says:

    Butch: this is loads of fun thinking through and the more I think the more complex it gets. With pumping fuel mass shift containment is the challenge otherwise the CG will “slosh” around with the fuel. More than likely fuel “slosh” only becomes an issue when the width of a tank is greater than the height and of course the positioning of the tank within the aircraft. Fuel pump(s) flowrate will need to closely match the change in wing configuration both ways, and obviously pumps will need to pump both ways. You’ll need to totally eliminate pumping air from an empty tank(s). Are you planning on using some kind of bladder(s) for the tank(s)? What kind of pumps are you planning on using? Just to rule out every other option, could any “bombs” in that bombay be lead weighted and moved on rail(s) within the bay?

  15. catman says:

    I agree with Jim J that pumping fuel (or water, for that matter) back and forth sounds overly complicated and frought with failure. The easiest thing to do would be to eliminate the rotary launcher hardware in the bomb bay for now to make room for a simpler mechanical system to shift the CG a bit as the wings sweep. The bomb dropping operation could be added later after you get the thing flying correctly if you guys absolutely have to have it.

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