GP Ultimate Bipe
03-22-2005, 11:20 PM
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GP Ultimate Bipe
Is anyone building this kit or have built one? I just ordered one and am curious if anyone has any tips or pictures of mods you have done. I built a Goldberg about 10 years ago and really liked it, but I need one that is smaller and easier to store. I plan on installing an O.S 70 surpass II on it and adding an extra servo for the ailerons. I had also thought about moving the elevator servo to the tail like my u-can-do 46. What do you think? Any suggestions will be greatly appreciated.
Rodney
Rodney
03-23-2005, 12:17 AM
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RE: GP Ultimate Bipe
I'm building one right now, but am doing everything according to the plans. I asked about dual aileron servos and was assured that a Futaba 3004 was sufficient. I'm thinking that I should have gone with my instincts. As for the elevator servo, a shorter control rod, or even a pull pull setup might be preferable, but I've heard that the GP Ultimate tends to be tail heavy, so moving it to the rear might be a bit of a problem unless you can shed some weight somewhere else.
BTW, this is only my third build and the plane almost falls together (hope it doesn't come back apart as easily
). I wish that I had taken a little more care fitting the wing sheeting, as I had to sand it pretty thin before I was satisfied and I had one fuse former (F10, I think) that needed some serious work to get it to fit properly, but overall, I've been thrilled with this kit.
BTW, this is only my third build and the plane almost falls together (hope it doesn't come back apart as easily
). I wish that I had taken a little more care fitting the wing sheeting, as I had to sand it pretty thin before I was satisfied and I had one fuse former (F10, I think) that needed some serious work to get it to fit properly, but overall, I've been thrilled with this kit.
03-23-2005, 06:44 AM
#3
RE: GP Ultimate Bipe
I have one of these. Its my fav plane 
I built it as per the plans. I am using a TT 61 pro for power. Mine ended up nose heavy and needed to add a bit of lead to the tail to make it balance as i wanted.
I also have one standard servo for the ailerons, so far no problems. I give this plane a thrasing and I love it. It does the most insane negative snaps you have ever seen.
It does build a bit heavy so keep it as light as possible.
I built it as per the plans. I am using a TT 61 pro for power. Mine ended up nose heavy and needed to add a bit of lead to the tail to make it balance as i wanted.I also have one standard servo for the ailerons, so far no problems. I give this plane a thrasing and I love it. It does the most insane negative snaps you have ever seen.
It does build a bit heavy so keep it as light as possible.
03-23-2005, 07:51 AM
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RE: GP Ultimate Bipe
I'm glad to hear it builds so easily, I cant wait to get it together. I think I will go with two aileron servos and probably will put the elevator servo in the tail (I don't care for the long push-rods) and will definitely use a pull pull on the rudder. I was also thinking of using some carbon fiber aileron connectors. I made all the push-rods on my U Can Do out of these and there is NO flex whatsoever. Did anyone dump the cowl and wheel pants for fiberglass ones? I hated the construction of them on the Goldberg and tossed them for the fiberglass ones.
Thanks for the response and keep the thoughts coming!
Rodney
Thanks for the response and keep the thoughts coming!
Rodney
03-23-2005, 07:58 AM
#5
RE: GP Ultimate Bipe
I'm building one right now and I dumped the ABS and got a fiberglass cowl from Stan's Fiber Tech
[link]http://www.stansfibertech.com[/link] It was like the differenece between night and day. Definately get the fiberglass
Hope this helps
Edited to update link with correct URL
[link]http://www.stansfibertech.com[/link] It was like the differenece between night and day. Definately get the fiberglass
Hope this helps
Edited to update link with correct URL
03-23-2005, 11:12 AM
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RE: GP Ultimate Bipe
I am building one and went for the Fiberglass Specialties cowl. I think any of the aftermarket cowls are better than the stuff in the kit
and alot less work. I am trying to keep it light but some of the wood in the kit is a bit dense. I plan on doing alot of sanding to help
minimize the weight so we will see how it all comes out. I am going to use an older ST 51 for power but may change to a 4 st later.
The ST is a nice light engine and should have good power. I am getting ready to cut out the turtle deck sides and finish up the fuse
and start sanding. I have also heard that the airframe comes out heavy so I am trying to pay attention to that.
Has anyone used the Robart hinge points on this kit ? If so what size ? I have some but am afraid they might be too big for the
wood.
I am going to use the kit control system as I have used it before on other GP kits and it has worked out fine. Although I WILL be
asking more of this plane than other planes I have built....
Sam
and alot less work. I am trying to keep it light but some of the wood in the kit is a bit dense. I plan on doing alot of sanding to help
minimize the weight so we will see how it all comes out. I am going to use an older ST 51 for power but may change to a 4 st later.
The ST is a nice light engine and should have good power. I am getting ready to cut out the turtle deck sides and finish up the fuse
and start sanding. I have also heard that the airframe comes out heavy so I am trying to pay attention to that.
Has anyone used the Robart hinge points on this kit ? If so what size ? I have some but am afraid they might be too big for the
wood.
I am going to use the kit control system as I have used it before on other GP kits and it has worked out fine. Although I WILL be
asking more of this plane than other planes I have built....
Sam
03-23-2005, 12:26 PM
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RE: GP Ultimate Bipe
I too am going to use the hinge points, they look to be easier to install and are very low in friction. How easy is the turtle deck sheeting to install on this kit? The best I can remember it wasn't too fun on the Goldberg. If any of you have pictures please post them, It will give me inspiration. I love to build but hate to cover, maybe since I'll be using Ultracoat on this plane I will get to where I enjoy it. I just have never liked monokote[:@].Who knows?
Please keep the thought and experiences coming...
Rodney
Please keep the thought and experiences coming...
Rodney
03-23-2005, 01:14 PM
#9
RE: GP Ultimate Bipe
The whole thing builds really easily. Turtle deck sheeting too.
Listen on that wing sheeting. Its already thin and light and gets thinner if more than final sanding is needed. Its so thin that CA can go right through the sheeting and glue you to the wing while you CA the sheeting into place so line it up well and straight. Make sure you join and sand your center sheeting and apply it as a unit, not in pieces (i think the instructions had the builder sheet the center section with small pieces butted up one at a time on the wing...sloppy way to build, maybe it was a different airplane).
The fuse is much stronger and heavier than necessary. Lighten wherever you can. I built mine 100% stock and flew it so hard than any other airplane would have split in two. Not this one. Blender after blender at high speed. I did break the forward cabane, but I never cracked the structure, even after a double cartwheel. A second aileron servo is a good idea. One per wing on the low and use interlinks between the ailerons. Make the interlinks with 4-40 rod and quality linkage on both ends. Quality clevises will work fine as long as the holes are not sloppy. Do not use the supplied 2-56 rod with one clevis and one z-bend. You will probably get a nice humming flutter if you do, although not usually catastrophic with an airplane of this size and strength.
It comes out nose heavy easily so a servo in the tail is perfect. If you can, frame it up and dry assemble it uncovered with everything but the last two servos for CG and then decide on the servo positions. You might decide to place both elevator and rudder servos in the tail.
Lastly, make sure you give every surface LOTS of throw potential. The surfaces are good sized, bevel for outrageous throw so its there if you want it.
Mark
Listen on that wing sheeting. Its already thin and light and gets thinner if more than final sanding is needed. Its so thin that CA can go right through the sheeting and glue you to the wing while you CA the sheeting into place so line it up well and straight. Make sure you join and sand your center sheeting and apply it as a unit, not in pieces (i think the instructions had the builder sheet the center section with small pieces butted up one at a time on the wing...sloppy way to build, maybe it was a different airplane).
The fuse is much stronger and heavier than necessary. Lighten wherever you can. I built mine 100% stock and flew it so hard than any other airplane would have split in two. Not this one. Blender after blender at high speed. I did break the forward cabane, but I never cracked the structure, even after a double cartwheel. A second aileron servo is a good idea. One per wing on the low and use interlinks between the ailerons. Make the interlinks with 4-40 rod and quality linkage on both ends. Quality clevises will work fine as long as the holes are not sloppy. Do not use the supplied 2-56 rod with one clevis and one z-bend. You will probably get a nice humming flutter if you do, although not usually catastrophic with an airplane of this size and strength.
It comes out nose heavy easily so a servo in the tail is perfect. If you can, frame it up and dry assemble it uncovered with everything but the last two servos for CG and then decide on the servo positions. You might decide to place both elevator and rudder servos in the tail.
Lastly, make sure you give every surface LOTS of throw potential. The surfaces are good sized, bevel for outrageous throw so its there if you want it.
Mark
03-23-2005, 03:07 PM
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RE: GP Ultimate Bipe
Thanks Mark. That is a good idea about putting the rudder back there too if need be. I could mount it inverted somewhere between the back of the wing and tail with an access hatch to get to the servo and pull pull linkages. I would say mine will be on the nose heavy side too with the O.S. 70 surpass II that I have for it. Are the wings thick enough to mount a standard size servo on it's side so they can be hidden below the hatch with only the horn exposed or do you think I would have to mount them on their backs like most everything else is? By the way what engine do you have on yours and what was your final weight?
Rodney
Rodney
