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Giant scale (80 inch) Lazy Bee

Discussion in '* Scratch Built Section *' started by iflyos, Dec 19, 2010.

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  1. iflyos

    iflyos Member

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    Thanks for the advice guyz! I will have to do something for torsional rigidity, and I think sheeting the bottom may just be it.

    With the combo spar/shear web installed, the wing is strong across the span, but it twists quite easily across the chord. I expect this would be a problem in flight, with loads changing across the wing. I have thought about, and may try, string bracing to eliminate the twist, before sheeting the bottom. If the string bracing works, then I can try to fly it like that..if not, then the weight added would be minimal, and I can still sheet the bottom.

    I still think I might have to add struts, just to be safe. It may not need them but my gut is screaming at me to add them. As soon as I can finish the wing up, and actually see how it feels mounted on the fuse, I will know for sure.

    Hmm...Giant handmade prop....I might have to try that!!
     
    iflyos, Dec 28, 2010
    #26
  2. 66tbird

    66tbird Moderator Staff Member

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    Yep, it's the twisting :x... fff just doesn't have the rigidity over a span of any length. One thing I have pondered is the lamination of two pieces of foam for these larger projects in fff for curved surfaces. Frank said he had good luck with the 1/2 stuff. Maybe he will chime in on bend abitity.

    Here are a few bits of info I found in building the 40-44'' Bees in fff. (It's raining and I'm bored so I'll type)

    Simple curved wing: Slow flight only, as in indoor low level cruise. Because when outdoors any gust of headwind and the wing warps into a washout condition. That induces a dive and the pilot reaction oscillation begins, and if its to bad will result in a wing warp greater than the elevator can compensate for. (which will also flex btw)

    Adding wing struts worked to a point. I ran mine from the fuse bottom to the tip joint LE and TE. Proper alignment took awhile. That increased control to a flyable point as long as airspeed remained boringly low. Aerobatics are still out of the question. Finding the max airspeed was quite easy. Since the low pressure area between the wing high point and TE increases with airspeed, and one side of the wing is going to lift before the other(between the fuse and strut) the wing loses lift and a turn is induced, and it got worse as the wing aged till un-fly-able. Faster you fly the more it turns.

    Adding a strut to the strut: Basically from center strut to center TE, like a diagonal brace to form truss. Helped a lot, made the plane fly-able at sub 80W/lbs level. Steep climb now OK and noticeably more power required for level flight. Still no aerobatics :( I popped a strut for a really awesome death spiraling, part de-parting, mushroom cloud of dust impact :lol:

    Bottom sheeting, plane four- 44'': Wing now solid and no longer an issue. Not as slow of flight but still walking speed landing and way less pitchy and stally For first time self stabilizing. Much better flier in the lazy sport category. Aerobatics are typical 3ch Old Timer.

    Problem now was empennage integrity, which required the same struts as the wing for the plane to be lazy sport/student comfortable. Another problem never resolved was the power on pitch up issue. Well unless one considers 30º downthrust a solution :lol: The planes loading now to great and a move to a cleaner, higher aspect ratio design was made.

    Side note: I've had the original balsa versions in two sizes and didn't have as bad a power on pitch-up issue, but they didn't have the power to weight as the EP version or as thick an airfoil. Also being built up they were far more rigid. Good tight quarters fliers. The .15 size (w/OS.25) was my touch and go fun fly bird for a year till the 'Hots' came out.


    I'm looking forward to your big Bee.
     
    66tbird, Dec 29, 2010
    #27
  3. rcav8r

    rcav8r Moderator Staff Member

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    rcav8r, Dec 29, 2010
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  4. rcav8r

    rcav8r Moderator Staff Member

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    As mentioned earlier in this thread I plan on doing a foamy Kadet Sr. The wing will be built up like the original, just using foam, so that shouldn't pose any issues.
    I plan on framing the tail with 3/8" balsa (using ping foam). Do you see any issues with the integrity of this? The original wood one was only 1/4" balsa, and I had a highly modified 10.5# one for years (actually still flying as I gave it to a flying buddy when I went all electric in 2002, and I had it about 10 years) with no problems, so simply framing the foam tail with balsa SHOULD work, right?
     
    rcav8r, Dec 29, 2010
    #29
  5. 66tbird

    66tbird Moderator Staff Member

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    66tbird, Dec 29, 2010
    #30
  6. rcav8r

    rcav8r Moderator Staff Member

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    Yep that's it; frame the foam.

    Yea, I hear ya on chasing strength with weight thing. I really think I can have a solid kadet and still be reasonably light. My old one was 10.5# but flew GREAT. Handled the wind very well, and came in like a feather if I wanted. I actually had a tail wheel on mine as I came close to wearing down the 1/4" stick at the tail landing nose high.
    Along the same lines. Mine was built stock ( except for the addition of the flaps and ailerons). That is nothing was modified on the airframe to make it stronger. I flew it like that for about 10 years, and flew it hard. The guy I gave it it, immediately beefed it up as he said he didn't trust it ( even though he saw it fly for all those years). He sheeted the entire fuse and tail. Added ply bracing all through the wing, and as a result needed a .91 in it. He let me fly it after he was done. Man the thing flew like a PIG. Not even close to the same plane. A pattern Kadet as you may say ;)

    And no it won't be pink... well all of it won't anyway. I'll be covering with WBPU and .5 ounce FG cloth and paining. I did have a pink Kougar once thought, EASIEST plane to see in the sky no matter what kind of sky it was. Boy was the end of it's long life a funny story...
     
    rcav8r, Dec 29, 2010
    #31
  7. iflyos

    iflyos Member

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    Well, not much to tell, except I played around with lighting, and got the power system ordered.

    Power will consist of:

    Turnigy 42-60 500KV
    Hobby King SS series 60-70amp ESC
    Turnigy 5amp Switching BEC
    Flightmax 5s1p 3000mah batteries.

    As mentioned before, this will (by original design) be a slow flying airframe, so it doesn't need allot of speed. I should be able to run a 14" prop no problem. Pitch is undecided, but I also could run a 13" three blade.

    I had one 3 meter amber LED strip in the shop, so I layed it in the fuse, and powered it up. It looked GREAT glowing from the inside, so I ordered 2 each of the red, green, and white strips to use in the Bee.

    I have decided to sheet the bottom of the wing, but I can't do that till my goodies get here. So, I am pretty much at a standstill till then. I can, and hopefully will, get the custom wheels/tires made, so I can at least get it sitting up on the gear.

    This sure is gonna BEE fun!!!

    Tim
    AG4RZ
     
    iflyos, Jan 2, 2011
    #32
  8. Evil-Tunes

    Evil-Tunes Moderator Staff Member

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    I was thinking about this In a 5 am morning daze as I'm waking up. What If you put two CF arrow shafts in the Wing. That should help with the Wing Warp. I would hate to see this wing bottom plated. or strutted for that matter.


    Cheers E-T Attached files [​IMG] Lazy Bee.E-T 80 v2.0.skp (7.8 MB)Â
     
    Evil-Tunes, Jan 3, 2011
    #33
  9. iflyos

    iflyos Member

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    Lemme play with that. That would save some weight, and be allot simpler!
     
    iflyos, Jan 3, 2011
    #34
  10. 66tbird

    66tbird Moderator Staff Member

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    Great idea ET ;)
     
    66tbird, Jan 5, 2011
    #35
  11. iflyos

    iflyos Member

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    OK, Guyz...a little more info. AUW with the power system (including battery) and lights is 4 pounds 1 ounce!!!

    I need to take some more pictures and get those up for you guys, but I am pretty happy with the weight. I have a feeling I have allot more motor/power than i will be able to use, but that should mean LOOOOOOOOONG flight times cruising around with the lights on.

    There is no color at all on the Fuse or wing...just blue FFF. I think I might add a little patch of something to the bottom of one wing, just for kicks. If it flies well, then I might just have to do another one at some point, and make it pretty.

    Tim
    AG4RZ
     
    iflyos, Feb 13, 2011
    #36
  12. iflyos

    iflyos Member

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    OK...I got a few pics. Sorry for the lighting, late afternoon and all...and don't mind the yard, it is a wreck from this winter.

    Attached files [​IMG] [​IMG] [​IMG] [​IMG] [​IMG]
     
    iflyos, Feb 13, 2011
    #37
  13. Jnida63

    Jnida63 Member

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    :doubleup: :doubleup: :doubleup: :doubleup:
    Love it
     
    Jnida63, Feb 13, 2011
    #38
  14. 3DMON

    3DMON Moderator Staff Member

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    Nice! :good: It came out great!

    So when is the maiden?
     
    3DMON, Feb 13, 2011
    #39
  15. iflyos

    iflyos Member

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    Most likely next weekend if the wind cooperates. Maybe one evening this week if my schedule permits.
     
    iflyos, Feb 13, 2011
    #40
  16. 7up

    7up Moderator Staff Member

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    Looks like a nice big lazy flyer... the plane is cool too! :dance3:

    Can't wait to see it in the air.
     
    7up, Feb 13, 2011
    #41
  17. Crash

    Crash Moderator Staff Member

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    Awesome, Tim! I can hardly wait to fly it!! :D
     
    Crash, Feb 14, 2011
    #42
  18. KX-5

    KX-5 Member

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    I just love these BIG foamies!! They are much more challenging structurally to get into the air. Yours looks great and good luck with the maiden flight!
     
    KX-5, Feb 14, 2011
    #43
  19. iflyos

    iflyos Member

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    Thanks guyz! Lazy flyer :eek: I resemble that! :D

    Mike, you know you will get to fly it!

    KX-5, you are correct, the structural challenges are interesting, and fun! I know I have more to learn, but this first step has been allot of fun! I am sure there will be more to follow...

    Tim
    AG4RZ
     
    iflyos, Feb 14, 2011
    #44
  20. rcav8r

    rcav8r Moderator Staff Member

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    Lookin' good. It just doesn't look like an 80" span.... maybe because of the short tail.
    Can't wait for the flight report
     
    rcav8r, Feb 14, 2011
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  21. iflyos

    iflyos Member

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    Yes, the fuse length does make it look smaller...But scroll up to the pic where I am standing up next to the wing on end...I am 6'1", and the wing is quite a bit over my head!

    I sure hope it :flying: well!
     
    iflyos, Feb 14, 2011
    #46
  22. SlowBipe

    SlowBipe Member

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    Tim,

    Your plane looks awesome. You definitely learn a lot when you are building these giant sized foam planes. I used the same motor (Turnigy 40-60 500kv) as yours on my 8.5 lb 80" GiantBipe. The only difference was that I used a 24 x 4 prop and ran on 3 cells. With that I could cruse around on about 13 amps or 140 watts of power. The 24" prop was hand carved from poplar and would provide large amounts of thrust at 60 amps and full power. I was able to pull a loop with a little bit of a dive before. I wasn't brave enough to do that again. Lots of creeks in the airframe during the pull out.

    I guess what I am saying is that you will have unreasonable amounts of power on this plane when you fly it. Should make it lots of fun.

    I hope you have a very successful first flight. I love testing these slow flying planes as if something doesn't fly right, just bring it back down, adjust and take it up again. They make for pretty low stress flights.

    SlowBipe
     
    SlowBipe, Feb 14, 2011
    #47
  23. iflyos

    iflyos Member

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    That confirms it...I am gonna be way overpowered. Well, thats why the left stick is variable, and not on/off. :D

    The 80" Giant bipe is a thing of beauty, and if this lumbers around half as good, I will be happy. I am really looking forward to the maiden, and to loads of laid back 3 channel flying...skimming the ground in figure eights, etc. Thats where I hope the "Rumble Bee" really shines!
     
    iflyos, Feb 14, 2011
    #48
  24. SlowBipe

    SlowBipe Member

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    Ah! And now you have found the real joy in flying. It's not the balls to balls speed, but slow lumbering flight that seems to defy gravity. I think it is probably what the Wright Bro's must have felt on their first successful flight.

    Good Luck!

    SlowBipe
     
    SlowBipe, Feb 14, 2011
    #49
  25. SlowBipe

    SlowBipe Member

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    I also used the same motor in my .60 sized Hanger 9 Ultra Stick. In that plane I used a 15-8 propeller and a 6 cell pack. I think that amps were about 40 at full throttle. All up weight was 6 lbs and it had unlimited vertical and very aerobatic.

    You could probably go down in cell count on your pack but keep the same prop size and still have enough power. Still on a first flight you want to make sure you have all of the power you need.

    SlowBipe
     
    SlowBipe, Feb 14, 2011
    #50
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