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Old Jun 07, 2007, 08:29 AM
Bernoulli+Newton=Lift
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Somewhere south of Chicago, IL
Joined Jan 2006
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Quote:
Originally Posted by golem
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 read an article recently that was discussing tip-stalls (which may be what Stephan's plane is doing), and it stated something which caught my attention. It said, "A wing can stall at any speed."

I kind of went, "Hey... I wonder....?"

I suppose it's possible that the shape of the wings (4-40 style airfoil) combined with the enormous surface area AND a 3 degree incidence on the upper wing is creating NEGATIVE lift above certain speeds. "A wing can stall at any speed" would certainly seem to apply here. FULL UP elevator is required to yank the Biggie Go Bipe out of these dives, and even then (as I recall) it really helps to cut back the throttle too.

I raided a servo or two from that plane to complete my Stephens Akro, so as soon as my United Hobbies order comes in, I can replace the missing gear, and see about modifying the wing supports. I'll let you know how it goes.
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Old Jun 10, 2007, 01:51 PM
John Cock...tos...ton
Stephan8's Avatar
LaGrange, GA
Joined Oct 2006
117 Posts
Hey Guys, (Magic and Golemm)

I know its been a while but as soon as I can i will add some video of the balsa bipe I built. It did the samew thing as my go bipe. It seems to rollmove when I turn left or right.

My original go bipe flew great. It wasnt till i began messing with the design that things got weird.

So anyway....all the parts got removed so no more go bipe for a while. And Golem was right about the "Sweet Spot" on his. I have built two or three of the same design and one just always flies better than the other.

So anywho....Magic, just wanted to say thanks again for all your input anddesign.

Stephan
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Old Sep 02, 2007, 01:44 PM
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I ALMOST scrapped this plane yesterday. I was getting another plane ready to fly and I kind of wanted the servos but I decided to give it one last try before I junked it.

My biggest problem with the design was getting the removable wing the stay in the same position after I zero'd the aileron servo. Since the servo, and the wing are on two different parts of the plane, any movement of the wing results in the ailerons being tweeked out of position pitching my airplane left or right. To fix this I put little bamboo bracers to hold the wing completely in place. IT WORKED!!!! This thing flew GREAT and it remained trimmed correctly for two full battery packs!!
-Pictures below

I am using a Blue Wonder 1300 KV with Hextronik 620 mah 3 cell batteries. My wing span is 1-2" wider than the original design it order to keep the wing loading down.

I am also working on how to make the landing gear strong enough to withstand less than perfect landings, any suggestions? RIght now I am going to make them removable and see if that works(probably a bad idea but what the hey).
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Old Sep 03, 2007, 08:35 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
1,952 Posts
Quote:
Originally Posted by Kurpal
My biggest problem with the design was getting the removable wing the stay in the same position after I zero'd the aileron servo.
Hey Kurpal - glad you didn't junk it!! I did the movable wing so that in less-than-perfect landing, the wing doesn't rip off, it just gets bumped to an angle. It generally takes several rubber bands on it with sufficient tension to keep the wing in place. Glad to hear you found a way to make the bamboo sticks keep it in place even better!

Quote:
Originally Posted by Kurpal
I am using a Blue Wonder 1300 KV with Hextronik 620 mah 3 cell batteries. My wing span is 1-2" wider than the original design it order to keep the wing loading down.
- Nice set up - should fly for a long time with that rig.

Quote:
Originally Posted by Kurpal
I am also working on how to make the landing gear strong enough to withstand less than perfect landings, any suggestions? RIght now I am going to make them removable and see if that works(probably a bad idea but what the hey).
I've had the same issue with mine. I essentially tried to make the landing gear like a Slow Stick - GWS uses a single plastic piece on the "stick" that the wire is inserted into. I tried doing the same, except building it from scratch using plywood and epoxy. It sort of works. Basically the best thing I can say is better landing make it last longer! If anyone comes up with a better design for that, please share!!
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Old Sep 03, 2007, 11:03 PM
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I scratched the landing gear idea. I learned to fly is low and slow enough to just pluck it out of the air by the wing.

Yeah, the set up I am running yielded me a flight time of 22 minutes. Better than most of my planes. I also was able to run my 1200 mah battery pack on this plane without any noticable difficulty. THat should give me 35+ minutes flight time.
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Old Sep 04, 2007, 03:25 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
1,952 Posts
Quote:
Originally Posted by Kurpal
I scratched the landing gear idea. I learned to fly is low and slow enough to just pluck it out of the air by the wing.
Another option is to flare it into some thick grass. Bring it it low, with barely any power, and about 2 feet up, cut power and just before it hits, bring the elevator up just enough to bleed off additonal forward movement till it stalls and drops down. Shouldn't hurt anything that way.

Quote:
Originally Posted by Kurpal
Yeah, the set up I am running yielded me a flight time of 22 minutes. Better than most of my planes. I also was able to run my 1200 mah battery pack on this plane without any noticable difficulty. THat should give me 35+ minutes flight time.
!!!!

Wow! Never even considered my 1200mAh Lipo on my LGB! I was always thinking "Lighter is better" so I don't think I ever went over a 500 mAh pack. But now that you've mentioned that - - - I think I may just have to try it....
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Old Jul 07, 2009, 08:33 PM
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Maryland, USA
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Hi magic612! Been a looooooooong time!

I continue to fly my original LGB, just took it out for another couple of spins only yesterday. Of all the planes I've built since then this continues to be my favorite based on it's very wide flight envelope. Slow, Fast, Mild, Wild...she does it all! On top of this she's so easy on my batteries that I am still using the same 2 hexTronik's I bought for this plane back in Dec 2006.

My LGB did get about a 7 month rest as I curtailed my flying after the passing of my father back in October of last year. He was my sole flying partner so it warranted a little time off. It just so happens that this LGB was also his favorite plane to watch fly especially since it could be flown in a quite realistic manner. So, as poor as it is, I figured I'd post a little clip in tribute to him. I believe it's from late last summer (just found it on an old tape). I cut out all the crazy (aerobatic) flying and simply showcased the sedate character of your design.

Thanks again for posting the plans and allowing me and my father to enjoy this plane for the last couple of years.

Cheers!

Little Go Bipe (4 min 34 sec)
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Old Jul 07, 2009, 09:25 PM
Bernoulli+Newton=Lift
magic612's Avatar
Somewhere south of Chicago, IL
Joined Jan 2006
1,952 Posts
Hey golem! Long time no see for both of us - I took a break from flying for a while as well. I've really only "been back" for a few months. Can't say mine was the same reason as you; I'm sorry to hear of the passing of your father. But I'm glad that this plane was something the two of you were able to share, and that truly warms my heart.

Thanks for sharing the video - I've got a couple other designs out there now, too. One of them is another biplane that I designed to fly in my backyard, which amounts to about 40' x 50'. Works pretty well too! It's called the "BYOB" - Back Yard Outdoor Bipe. Maybe something else to give a whirl? You did such a nice job adding a full fuse to the LGB, I'm confident you would be able to do the same on that one too, should that plane catch your interest.

Again, thanks for sharing the video. Much appreciated.
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Old Dec 18, 2009, 09:27 PM
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Joined Dec 2009
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Steps List

Hey magic612 i was wondering if you can do a complete list of the steps to build the plane i really like it i already started cutting the parts but is a little difficult for me to build it without a solid series of steps if you do me the favor i will be most pleased
Thanks and really cool mini plane
Masavi

Please please please i really like the plane
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Old Feb 28, 2010, 04:12 PM
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I built an EPP Little Go Bipe a year or so ago. I scaled it to an 18 inch wingspan and added a full fuselage to provide structural strength. I've had a great time flying this airplane in the street in front of my house.

It was my 4 channel trainer, and survived an incredible amount of abuse. I found it to be a good trainer since it requires both rudder and aileron to turn. Learning to use the rudder made the transition to my first 3D plane much easier. As built, the plane can be flown 3 channel without ailerons. The 3 degree upper wing incidence makes it roll upright just as dihedral would.

I routinely fly it in wind strong enough so that it moves upwind at a slow walk. A flag in the neighborhood is flapping in the breeze with this amount of wind. I can turn the plane 180 degrees in the width of my driveway (about 15 feet) with a steep bank turn. It doesn't roll well, and flying upside down is essentially an inverted harrier. Upright harriers are easy with no wing rock. If I were building the plane again, I'd make the wing incidence the same on both wings so the bottom wing would provide more lift and the ailerons would be more effective. With both wings at 3 degree incidence I think the plane would be even more fun and floaty. The elevator could use more authority, so I'd make that bigger too.

With a stock 10g motor and 7x3.5 GWS prop, the plane needs to dive to perform a loop. I rewound the motor and with a 6x3 GWS prop, it can loop nicely on full throttle. To me the rewind is much better than the stock winding. With either motor, I cruise around at half throttle. Flying at full throttle for a while will get the stator to about 150 degrees F. The bell remains much cooler. I originally mounted the motor with hot glue, but the motor would get hot enough to soften the glue and fall off.

Honestly, I'd suggest using a Cyclon Nano and using some combination of lighter battery (350mAh), lighter servos, or fewer servos to keep the weight the same. The Cyclon provides roughly twice the thrust at the same current. I put a Turnigy 2204 on it for a while. Run times were the same, but the plane was 18 grams heavier with the extra weight of the motor, controller, and 3 grams in the tail to balance it. I missed the floaty feeling and went back to the 10 gram motor.

The are two 1mm carbon rods to brace the wings. The rest of the plane is EPP, strapping tape, and hot glue. Strapping tape on the leading edge of the wings makes encounters with mail box posts and telephone poles a non-event. I have a DXF drawing of the major parts - it would be a stretch to call it a plan. I also have pictures of the assembly process.

Wingspan: 18 inches
Wing area: 225 square inches
Weight: 133 grams AUW, 103 grams without battery
Servos: 4 HXT500
Battery: 2S 460mAh or 2S 350mAh lipo
Reciever: Spektrum AR6100
Controller: 6A Turnigy Plush
Motor: Hextronik 10g rewound with 17 turns of 29awg
EPP: 1.3 pounds per cubic foot, 0.2 inches thick (6mm)
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Old Mar 06, 2010, 05:29 PM
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Maryland, USA
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Originally Posted by frontyardflyer View Post
I built an EPP Little Go Bipe a year or so ago. I scaled it to an 18 inch wingspan and added a full fuselage to provide structural strength. I've had a great time flying this airplane in the street in front of my house. ...
Hi frontyardflyer!
Great to see another person enjoying this design of magic612's. Really is such a great flier it would be nice to see more built and flown. My 118% full fuse LGB is very much overpowered and a bit portly at a hair over 7oz but still excels at low-n-slow so I can only imagine how well yours must fly close-in considering it's paltry 5.1oz AUW.

I like some of your design tweak ideas. If you get around to any of them it would be interesting to hear how they work out. Mine flies well inverted but like you noted the tenancy is for the tail to hang decidedly low, more-so at lower speeds. In addition to the overall 18% enlargement of mine I did also enlarge both the rudder and elevator surfaces an extra few %. With this she is very responsive at low speeds and crazy responsive at high speeds. A contributing factor at slower speeds could also be the fact that I'm spinning an 8x4e prop which floods the control surfaces with lots of air.

I'll say it again (just like a broken record) this is without doubt my favorite plane to fly. Your post to this thread has awaken me from my winter hibernation (snow, cold, windy, soggy, etc) and provided me the impetus to dust her off, check linkages and charge the batteries...should see some air time this coming week.

Always great to see build pictures especially when they includes design and/or material changes so I for one would enjoy you sharing.

Cheers!
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Old Mar 06, 2010, 09:34 PM
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More pictures...

I've really enjoyed flying mine. It's fun to do tight banks right in front of me and generally cruise around. For storage, I keep it upside down on top of my bookshelf, resting on the wing, with the tail hanging out so it won't warp.

I originally had it setup to use flaperons. For some reason I never set them up when I switched to 2.4GHz. I'll have to try it again on a calm day with the lighter 350mAh batteries I have now. I'm a big fan of low and slow.

I used Welder glue thinned just a bit (maybe 25%) with Goof Off professional strength. The regular Goof Off doesn't dissolve the Welder. The hinges are hot glue and hold up very well. Repairs are hot glue.

Here are your pictures. I actually paint my planes now
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Old Jul 11, 2010, 08:30 PM
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Joined Jul 2010
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Little go Bipe trial

Hi Magic612 and everyone else! I'm an airplane enthusiast myself and i came upon your design. I decided to try it with 3mm depron foam, a brushless emax motor (because i didn't want to go out and buy the A drive setup and I already had it with me), microreceiver, microservos and tenergy 900mAh battery. It was interesting to form the airfoil on the two wings and hold them in place for gluing, but after some work i completed it in a short amount of time.

I tried flying it at a small park with a sidewalk as a runway and essentially got no more than 10 second flights because of many reasons. My battery was starting to die, it was very difficult to take off of a narrow sidewalk without a rudder wheel, and it was dark and i didn't have my contacts in... This was slightly problematic, so the next day I threw it off of a hill and came to the conclusion, with the help of my dad, that the propeller was too small to support the plane because of how it stall turned immediatly. I, being a very impatient person, wasn't thrilled about waiting for the 7" props to come it rather than the 5" I had been using before, but it sure was worth it!

Off the ground it took! proving that you don't need a rudderwheel if there's sufficient power on the plane! it had taken off just as easily as i had expected the first time, so it was nice to experience my expectations. It flew well, but unstabily because of the thin foam/large motor combo and heavy wind. Remember, I'm not patient so it wasn't even an option to try it later.. After a quick landing to readjust the battery's position, my second flight was a good 45-second flight until i became disoriented in the sun and crashed it. The damage wasn't bad, other then a broken prop and some foam damage. however i decided to use a thicker and more sturdy foam so it would fly more stable and i am currently in the middle of fixing my stripped out microservos and reattaching the wing.

here are the specs of my final Little Go Bipe-

Emax CF2805 brushless motor.
Some ESC that came with it... sorry bout the lack of knowledge here
Futaba microreceiver, very light.
3.7g microservos (3) for $4 apiece on Ebay! (which have now stripped out)
Tenergy 900mAh, 7.4v 10C and 25C batteries. (one at a time)
7" GWS 7035 Propeller
Some Depron that's like 4 or 5 mms.

The overall weight is something over 7 ounces, but that large, effective motor and large prop combo is enough to push it with extra power!

I'm sure I'll be able to get a video here soon once i do the annoying task of servo replacing... I just thought i'd let you know about your plane's successes and how much i have enjoyed it! Lemme know what you think!

Alex
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Old Jul 14, 2010, 02:35 PM
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Maryland, USA
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Originally Posted by PianoMan5 View Post
Hi Magic612 and everyone else! I'm an airplane enthusiast myself and i came upon your design. I decided to try it with
Hi Alex!
Great account of your efforts with this plane. Was good to hear you had her up and flying...before the sun conspired to shorten your day. That 7+oz weight should work fine, just means she'll fly a bit faster than designed. Given the current motor and robust electronics I'd add a couple inches to the wingspan making it a lot more floaty and slower flying.

I fully understand the motor you're using was a matter of convenience but unfortunately it's much better suited for small prop/high RPM applications given its 2800kV. Even with the GWS 7x3.5DD prop the specs I found for it shows a 13amp draw which will be beyond the capabilities of your 900mAh 10C battery so I'd be a bit cautious with that one. If you can swing it there are a lot of nice little 1000kV-1300kV motors (=/<24oz) for really really cheap that would be perfect for this plane. With one of those you could turn a 7" or 8" slow-fly prop nice and slow. You'd get more than enough thrust while probably also keeping the amp draw around 6 giving a lot more flight time!

Looking forward to seeing pictures and/or vids of your plane. This is such a nice little design it's great to see people giving it a go. Not sure what happened to magic612. He seems to have disappeared from the board some time ago which is a shame. There were some pretty interesting designs he kindly shared.

Here's hoping you get some good weather and quality air time!

Cheers!
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Old Jul 14, 2010, 02:53 PM
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Maryland, USA
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Originally Posted by frontyardflyer View Post
I've really enjoyed flying mine. It's fun to...

I originally had it setup to use flaperons. For some reason I never set them up...
Hi frontyardflyer!
Dang me! I asked a question, you followed up, I failed to respond.

Anyhow, thanks for the pics! I see you mentioned flaperons. Did you ever get a chance to employ them? If so, how did it work out?

I also like the idea of hangering her upside-down. That trick may have staved of my unintentional anhedral. Still, I'm not complaining. As I have way overpowered my version the anhedral seems to make it a much spunkier handling model, not to mention, inverted flight is probably just a smidge more stable.

Cheers!
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