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Old Apr 28, 2007, 10:36 AM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
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Quote:
Originally Posted by Stephan8
Hey Golem,

Well, I got some work to do. The plane has a weird tendancy to dump over when turned to the right.
It suddenly occured to me why this might be happening. Do you have the servo for the ailerons centered over the fuselage spar, or is it off to one side? If it's off to one side, and you have one aileron pushrod longer than the other, there will be different throws to each side of the ailerons depending one which way you turn. So it's possible that if one is longer, it's pushing your ailerons further when you turn right. If you have EPA on your radio you might be able to fix part of it with that - the other option is to make sure that the control horns are equi-distant from the centerline of the aileron servo. That may mean putting one horn 3/4" or so further out on an aileron, with the other one close to the edge (if that makes sense).
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Old Apr 28, 2007, 12:49 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
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Mini Go Bipe plans

Quote:
Originally Posted by golem
Hope you get a chance to post both plans (especially if it's not a direct scale-down)
Well, not BOTH plans yet - just the "Mini" for now. And no video yet either - need calmer conditions plus a time when my wife can operate the camera for me.

Anyway, plans should be mostly self explanatory for those that have read the "Little Go Bipe" build log. The only thing significantly different is the "tabs" used to hold the wing on. I'll take some pictures to show detail of some of those sections later on.

I did some quick calculating, and discovered there'd be no significant weight difference for this plane to use 2mm Depron or 3mm Depron. And the 3mm would probably add a touch of strength to it that the 2mm lacks.
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Last edited by magic612; Apr 28, 2007 at 01:00 PM. Reason: Info on Depron weights
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Old Apr 28, 2007, 09:29 PM
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Maryland, USA
Joined Mar 2006
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Quote:
Originally Posted by magic612
Well, not BOTH plans yet - just the "Mini" for now.
By "both", I was really referring to plans for the mini and a vid. One down, one more to go...just continue being nice to the Wifie B. DeMille and my request #2 should be fulfilled.

As for the plans, THANKS, perfect! Enough detail there to get the ball rolling when I acquire the correct foam. Tempted to split some of my blue stuff in the meanwhile.

Btw, don't know if you have run across my posting about the Star Cobra (3F) . Now that I have had a chance to test it in calm weather I can assure you this is a prime candidate for a backyard flier if scaled down just a tad more, maybe a 50%'s at 5-6oz as opposed to my 70%'r.

Thanks again for everything!

Cheers,
golem
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Old May 04, 2007, 05:49 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
1,952 Posts
I have to say I'm disappointed in my flying skills with little, lightweight planes. I SUCK!! I've managed to nose the "Mini Go Bipe" a number times into the ground not long after launch - and because the fuse is just a 1/4" stick of balsa to save weight, it keeps snapping at the LE of the wing. Grrr....

Must. Fly. Better.

Anyway...

I've finished up the "Biggie Go Bipe", and it weighs more than I initially expected - it tips the scale just over 11 ounces. BUT - the cool part is, since it's got such a HUGE wing area (4.32 square FEET!!!), it ticks in at about 2.6 ounces per square foot of wing loading. That's a lighter wing loading than the Mini!

Of course, with that much wing and correspondingly that little weight, it'll be a sail with any substantial wind. So I hope to maiden her this weekend, if the wind dies down a bit - it's been in the 10-20 mph range for the past 5 days! Ahh!!!

My hope is that it will not only "float" along with barely any effort, but also zip right up to some decent speeds for some fun aerobatics. THe control surfaces are quite large, so it should perform snap loops, rolls and other stunts with relative ease, while also being a docile floater. Kind of a "multi-purpose" plane - like a Taurus hiding an SHO V-8 under the hood, you know?

I'll post my results as soon as I get a chance to get her up in the air, and hopefully a vid or two as well.
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Old May 04, 2007, 06:59 PM
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Maryland, USA
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I love it! 4.32 @ 11oz/2.6...that's gonna be hoot to fly! Sounds perfect for one of those little blue-wonder motors. Hopefully the wind will break and you get some flights in allowing for pictures, details...and video, of course!

My LGB was dusted off a few days ago after a couple of months focusing on a few other planes. Also wanted to upgrade from the GWS RX I had in her due to the increasing amounts of glitching noticed. It was just a bit windy with small gusts at the park but the LGB still flies like a dream. She now sports full 3D deflection and boy does it do some crazy maneuvers. I can actually cartwheel so quickly that, because of her size, she just looks like the moon crossing the sky given its mottled gray coloring.

Oh, forgot to say I almost lost her on the initial ROG take-off. I had inadvertently changed the sub-trim on my radio for that model while setting up another one. Upon getting airborne she shot straight up and wanted to immediately perform a loop. It required 3/4 down on the elevator stick just to keep her level! One may not think it but I found it quite disconcerting and somewhat challenging to fly smoothly enough to land while having to apply that much down stick. Thankfully she landed safely.

Looking forward to more info on her bigger sister.

Cheers,
golem
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Old May 04, 2007, 09:12 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
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As per usual - COULDN'T WAIT!!

I looked outside as the sun was going down, and the wind was almost non-existent. So I quickly drilled the wheels to the proper size, collared them on, CA'd a temporary tail skid in place, and headed down to the (empty) library parking lot.

Quick range check, added in 65% negative aileron expo, 45% negative elevator expo, gave her just a tad of throttle - AIRBORNE! This plane needs almost NO thrust to take off. I may have had it at about 1/5 throttle at most! I wanted to check slow-speed flight more than anything, so I carefully checked aileron, rudder and elevator functions in flight. No problems.

Then, I wanted to see how slow I could fly her. Seriously, I had to have had 1/8 throttle - something barely moving. FINALLY got it to "stall" (if you could even call it that). The slower I went, the more it just dropped the tail down and kept right on going. A "stall" consists of the plane finally losing sufficient airspeed to stay airborne, at which point I'd add just a touch of throttle, and it would continue onwards - with almost no loss in altitude! Crazy!!!! I even managed a landing that consisted of NO ROLL of the wheels - just kept throttling it back, pulled the nose up about 2 feet off the ground, and she settled right down on all three points with no forward motion.

Finally, I wanted to check how it went from slow speed flight to high speed. Now, I'm flying in an area that has tall trees on two sides, a building on the third, and a high security fence on the fourth, and is approximately 150' x 150' square. Not an enormous amount of space for a high speed plane, to be sure. (Not to mention, now it's starting to get dark, as the parking lot lights were flickering on.) Basically, I managed to turn her at the far end, with some decent altitude, and punch the throttle to about 3/4 - she MOVES! I did a quick snap loop, and pulled the throttle back to turn it around again. Managed a (badly executed) roll, so I'll have to try that again another day, as I didn't want to risk another one with the diminishing light.

All in all, I REALLY think this is a fun plane. It will saunter around as slow as you please, with little input required, and TAKE OFF if you want to "show off". Fun, FUN, FUN!! I'll post plans later - I really hope some of you guys like this plane - it's super simple to make, and I think it's a lot of fun to fly. Plus, it's simple to add a fuselage body to it, without adding any significant weight penalty.
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Old May 08, 2007, 07:58 PM
John Cock...tos...ton
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LaGrange, GA
Joined Oct 2006
117 Posts
Hey MAgic,

I will definately build the larger version. I think my electronics are too heavy for the regular size....so please post the big go bipe and maybe I can throw it together.

Or I guess I could just size up my originals....

Anyway, nice work

Stephan
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Old May 09, 2007, 05:39 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
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Stephan -

I'll post the larger plans soon. They are slightly different than the "Little" version, to account for the heavier materials and stresses on various parts.

Nice to see you back around!
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Old May 10, 2007, 09:24 PM
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Maryland, USA
Joined Mar 2006
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Hi magic612,
Great to read that positive flight report, has me intrigued. Especially hearing the design flies so well with what sounds to be only structural mods. Your mentioning of the full fuse mod also really catches my attention. Makes me anxious to scale up my LGB! I already have everything I need for that so it should come to fruition before the MGB.

Will hold out for you to post plans so I can make sure there are no real dimensional changes.

Cheers,
golem
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Old May 13, 2007, 09:12 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
1,952 Posts
Hmmm.... the "Biggie" version has a weird quirk to it.

At slower speeds, it flies just great. It'll harrier - heck with a touch of wind, it'll harrier with backwards groundspeed - it'll saunter around nice-as-you-please, pull loops - inward AND outward - all in all, not bad at slow speeds.

But here's the weird thing - at WOT, it will do something strange. When flying upwind, it will suddenly DIVE. Out of nowhere. No stick input downward at all - sometimes even with a touch of UP stick - WHOOSH! Heads for the ground.

Now in fairness to the plane, I probably need to do a couple things. One, my shim to keep the motor at a slight downthrust is just a shaved piece of balsa, and probably is not doing as well as, say, a wedge of basswood. Secondly, I'm not entirely sure she's balanced right yet - when gliding, she keeps "porpoising", which would indicate to me she's still a tad tail-heavy (yet oddly enough, she flies GREAT at slow speeds!). And furthermore, I have had to add in some "down" elevator to compensate for the enormous lift of the wings - remember, the "Biggie" version is sporting over 4 square feet of wing area, with an AUW that is around 3/4 of a pound. So the wing loading is EXTREMELY light.

But what doesn't make sense to me about that is the fact that the lower wing is a 0 degree AOA and the upper wing is plus 3 degrees. So I think I had to dial in some down elevator to account for the upper wing being plus 3 - at least at slow to mid speeds. At high speed, it does that weird dive - yet only seems to do it going UPwind. Downwind didn't seem to have that problem.

Granted, I was flying in somewhat gusty conditions (3-8 mph winds) with essentially two sails on a stick, so it could be downdrafts pushing the plane down. Other than that (and the other previously mentioned things), anyone have any ideas? I know I need to check the other stuff, but if anyone's had any similar problems, I'd be interested to know your thoughts on this.

Any ideas?
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Old May 15, 2007, 04:06 PM
John Cock...tos...ton
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LaGrange, GA
Joined Oct 2006
117 Posts
Hey magic,
just read your post and I can understand. My larger version did simmilar things at higher speeds.

Plus, i just put together an Accell arf bipe. Looks great but it flew the same as my other larger go bipe. It hardly would turn and all the sudden it dumps to one side. I checked the weight....side to side and cog but all normal. Still...its like it stalls when trying to turn it.

Could this be some weird...unknown newbie property of biplanes? Could the ailerons be creating stall. I dont know but its wearing me out. I crashed the larger version of my go bipe yesterday trying to figure it out.

Just keep scratchin my head. I hate to scrap stuff just to start all over. but...

so anyway, just a little randominput from my bipes.

Stephan


P.S. I love your blu trainer one! looks great.
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Old May 15, 2007, 04:17 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
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Stephan -

I don't know. I built a balsa / plywood biplane (it's the red / white / blue one in my avatar) that didn't fly so great, but I'm SURE that was because I wasn't using enough power - it was a geared / brushed system. I'm planning on upgrading that to brushless in a few weeks, plus I'll be using a LiPo with more amps to give. I guess I'll see how that goes, since that plane wasn't my design.

And mine doesn't seem to have the issue yours is - this is just the "Biggie" version that will suddenly nose-dive while going into the wind. I may build a second wingset with a smaller undercamber and zero AOA for both wings, and see how that flies. Plus, I need to check the other things I mentioned first, too. I don't know - I'll keep you posted.

And the thing is - golem LOVES the "Little Go Bipe" and can make it do all sorts of things. Might be my "dumb thumbs". I know I'm getting better - I really don't crash much anymore with any planes, but there are some "heart-stopping" moments with the "Biggie". That's why I haven't posted the plans yet - something seems amiss. I just haven't figured out what yet, and I don't want to push a bad plan onto others.
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Old May 16, 2007, 02:55 AM
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Sorry to hear about the quirks being shown in those larger builds guys. That's one of the reasons I've designed and scratched so few, takes an awful lot of design tweaking to work out all the kinks. That which has been described in the last few posts could very likely be a combination of contributing design factors making it all that much more difficult...I get anxious and would rather be flying although the sense of accomplishment upon finding just the right combination of redesigning is always grand.

magic612, saying that I LOVE the LGB is actually a bit of an understatement. This is my absolute favorite airplane now that all I fly is electric. She is wild-n-crazy with no limits AND old-timer lazy. A telling tidbit; My brother-in-law is visiting for two weeks and has never flown R/C. We've been to the park flying my full hanger over the the course of the past week. He's had a bit of stick time on my "Miss Stick" while watching me fly the remainder. Of the 5 other planes I've been throwing around the sky he actually said to me that when the LGB is in the air it is easy to tell she's my favorite. Not only because of the ginormous grin I sport but also because of the energy and fluidity covering the full flight envelope.

Just this evening we finished building him a FFF "TRAINER One" designed by gpw. This is really a tease as he'll fly it here for the next week (weather permitting) and before leaving to go back to NY I'll be pulling my electronics from it. He'll then have 3.5oz of foam to hang on the wall back home. At that point I am seriously contemplating scaling up my LGB. A no-design-change scaled to 170%-180% from the current 23" wingspan. Hopefully I can accomplish it without introducing any unintended design changes (i.e incidence, airfoil, thrust angle, etc.). I think I got lucky and hit the sweet spot with my LGB build.

Gonna keep an eye out to see if either of you can work out the quirks in the current bipes.

Cheers,
golem
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Old May 16, 2007, 09:13 AM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
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See, that's the weird thing, golem. My "Little Go Bipe" flies just fine - floats around nice and slow, and will zip up to higher speeds with snap loops and fast rolls no problem. And even the scaled up version flies fine SLOW - it's when it's going FAST that she exhibits some bad tendencies. And only occasionally too. I think I need to check some things on it first, before tearing it apart and starting over. I just didn't want to post plans without making sure I'd thoroughly tested it.

Maybe I'll at least take some pics of it so you can see a few of the (helpful) design changes I made for the large version.

And believe me, I really do appreciate what you've said about the LGB, and especially that it's your favorite airplane (it's my current fave, too ). Thanks again for the kind words.
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Old May 16, 2007, 10:03 AM
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Maryland, USA
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Quote:
Originally Posted by magic612
And even the scaled up version flies fine SLOW - it's when it's going FAST that she exhibits some bad tendencies. And only occasionally too.
That is the thing making it so difficult to understand. "Occasionally" when at speed sounds like a radio/servo glitch amplified due to the higher speeds (which is doubtful) or, more likely, the possibility that the bigger GB is actually flying on a razors edge due to a design parameter which leaves just a small change in AOA and/or wind to cause her to tuck at speed. Not too profound on my part I know.

I do believe you are on track with regards to looking at the wing incidence and under-camber. I'll bet a new set, or a massaging of the current pair, might just do the trick. Looking forward to hearing your progress. Also, if you would rather not post the plans (which might credit you with what you feel may be a questionable design in it's current state) I would be happy to see them in a PM.

Cheers,
golem
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