Build Thread for Rhythm 3D Bipe
#101

Well, I took it out tonight and there was a little more wind than I was expecting. I decided to try anyway and it was getting blown around pretty good. I was fighting to control it so I brought it down. The wind was really gusty so it was giving me problems. When I landed I noticed that the set screws holding the motor to the mount were loose and was causing the motor move around and vibrate a lot. I brought it home and tightened everything up. I guess that counts as a maiden? It lasted about 30 seconds, but it came home in one piece so I guess thats a good thing. Better luck this weekend I guess....
#102

Hello all , I looked at a lot of posts and did not see this question anywhere but if I missed it and it has been already asked I'm sorry ...
I am trying to set the COG on this plane and it is fighting me .. I am using my stand with the dowels on it but it is just so touchy I can't get a good reading ..
Why can't I set it using the "Hanging" method Just find the same spot where the COG on the bottom wing then transfer it to the top wing .. Then set up a string in that spot in the middle of the plane to "hang" it from and the plane should hang there level when the COG is correct ...
The COG as I read it in the mannuel is 2&5/8 inch in from the front edge of the of the bottom wing ... right??? .. This is the last thing I need to do before I fly it ..
I just want to thank everyone in advance for the help .. Don J.
P.S. Correction : I read the book again and the COG spec is taken from the TOP wing ... So that is even more of a reason why we should be able to use the " Hanging " method to set the COG
I am trying to set the COG on this plane and it is fighting me .. I am using my stand with the dowels on it but it is just so touchy I can't get a good reading ..
Why can't I set it using the "Hanging" method Just find the same spot where the COG on the bottom wing then transfer it to the top wing .. Then set up a string in that spot in the middle of the plane to "hang" it from and the plane should hang there level when the COG is correct ...
The COG as I read it in the mannuel is 2&5/8 inch in from the front edge of the of the bottom wing ... right??? .. This is the last thing I need to do before I fly it ..
I just want to thank everyone in advance for the help .. Don J.
P.S. Correction : I read the book again and the COG spec is taken from the TOP wing ... So that is even more of a reason why we should be able to use the " Hanging " method to set the COG
Last edited by diverdon; 06-21-2008 at 04:12 AM. Reason: correction
#103

I just measured back from the leading edge of the top wing made a line there on the underside and used my fingers to see if it would balance.
I noted the placement of the battery in the hatch and drew a line there so I could put the battery in the same spot next time.
I noted the placement of the battery in the hatch and drew a line there so I could put the battery in the same spot next time.
#104

Don, I just noticed in your post you said the manual said measure the bottom wing to find CG. That isn't correct. Measure the top wing! it will be real close to where the brace goes into the wing.
#105

I forgot to post the results of my second flight. The first flight was only about 30 seconds long since it was two windy, so I brought it down right away. The second time out was dead calm. I did an underhand launch and she took off straight out. It flew pretty well. I did a few rolls, loops, and something that resembled knife edge flight (still got to work on that). I'm finding my motor seems to be vibrating a lot for some reason...I'm not sure why. Maybe my prop is off balance? Nearing the end of my flight, the nut on the motor shaft loosened and didnt turn my prop anymore. The thing I don't like about these turnigy motors is they don't come with lock nuts, so they don't stay tight. I dont have any thread locker, so I used come CA for now. Other than that, I enjoyed the plane a lot.
As for balancing, I just use my fingers. IIRC, it balances right around where the carbon rods attach to the top wing, as the pastor said.
As for balancing, I just use my fingers. IIRC, it balances right around where the carbon rods attach to the top wing, as the pastor said.
#108

Here we go, finally a video! The quality isn't great since it was taken with a point and shoot type camera rather than a video camera. I didn't really do anything fancy with it, but you get the idea...
<object height="350" width="425">
<embed src="http://www.youtube.com/v/Rl155R5blNw" type="application/x-shockwave-flash" height="350" width="425"> </object>
<object height="350" width="425">
<embed src="http://www.youtube.com/v/Rl155R5blNw" type="application/x-shockwave-flash" height="350" width="425"> </object>
#110

Hello all , I looked at a lot of posts and did not see this question anywhere but if I missed it and it has been already asked I'm sorry ...
I am trying to set the COG on this plane and it is fighting me .. I am using my stand with the dowels on it but it is just so touchy I can't get a good reading ..
Why can't I set it using the "Hanging" method Just find the same spot where the COG on the bottom wing then transfer it to the top wing .. Then set up a string in that spot in the middle of the plane to "hang" it from and the plane should hang there level when the COG is correct ...
The COG as I read it in the mannuel is 2&5/8 inch in from the front edge of the of the bottom wing ... right??? .. This is the last thing I need to do before I fly it ..
I just want to thank everyone in advance for the help .. Don J.
P.S. Correction : I read the book again and the COG spec is taken from the TOP wing ... So that is even more of a reason why we should be able to use the " Hanging " method to set the COG
I am trying to set the COG on this plane and it is fighting me .. I am using my stand with the dowels on it but it is just so touchy I can't get a good reading ..
Why can't I set it using the "Hanging" method Just find the same spot where the COG on the bottom wing then transfer it to the top wing .. Then set up a string in that spot in the middle of the plane to "hang" it from and the plane should hang there level when the COG is correct ...
The COG as I read it in the mannuel is 2&5/8 inch in from the front edge of the of the bottom wing ... right??? .. This is the last thing I need to do before I fly it ..
I just want to thank everyone in advance for the help .. Don J.
P.S. Correction : I read the book again and the COG spec is taken from the TOP wing ... So that is even more of a reason why we should be able to use the " Hanging " method to set the COG
#111

I usually just plop it down into the grass as close to me as I can. Its great when I dumb-thumb it, the grass acts like somewhat of a safety net. Unfortunately, It can be a real pain trying to find and retrieve a crashed plane with all that grass. Theres a small access road that I stand on with a short strip of pavement, but its mostly gravel so I haven't tryed a ROG takeoff or landing yet.
#112
Member
Join Date: May 2008
Posts: 45

It's great to finally have video! Well, I finally maidened mine and I can't believe how slow this airplane can fly. Rudder authority is amazing and it knife edges with hardly any rudder input. Flew it twice but on the second flight one of the wheel pants flew off and then the wheel followed plus the ride side aileron linkage (those screw down easy connectors) slipped and got stuck about 30degrees (following a vicious snap roll). Needless to say this made landing very interesting especially since to fly straight both ailerons needed to be about 15degrees up, creating a spoileron effect and increasing the landing speed. Anyways, the bipe ended up landing all right but did a little somersault and weakened the struts where the bottom wing attatches to the fuse, but nothing a little hot glue shouldn't fix. Overall, this little plane flies really nice!
#113
Member
Join Date: May 2008
Posts: 45

aero-my turnigy motor vibrates slightly and is much louder than my other electrics, and this is with no prop! I think some of the turnigys can be slightly unbalanced from the factory, but if you haven't balanced your prop yet, get on it! That's most likely where the vibration is coming from. Also, I've never tightened my turnigy motor prop nuts anything more than with my hand, and they seem to tighten during flight due to the torque of the motor. I have my esc set for no brake, if your's is on brake, that could be why the nut is loosening. Oh, and how hot are your electronics when you land, and how long are you flying for? I've found the 10x4.7sf pulls 16amps and I'm a mile above sea level!
#114

Ministeve and I bought one on the 4th on sale for $24.95 . It took about 10-12 hrs to build but we flew it today and he let many non-3Der flyers fly it . Every one who flew it looked like an expert 3Der when doing K E s. Here's a couple in flight shots. I read in this thread someone paid $15 for it .WHERE? Steve liked it so much we went back to Hobby Ppl and got 3 more 1 for a spare ,1 for me , and 1 for his buddy
#115

Hi Everyone, As Al said... We built one this weekend... and it flys great... superb knife-edge flight it wants to hold a knife-edge like nothing I've ever seen... makes "everyone look like a pro... at $24, we had to get a couple extra kits...
Some Mods we did in the beginning paid off pretty good...
First, We Moved the servos much further back... I didn't like the idea of putting them that far forward, so we cut slots and mounted them one on each side and much further back... added 2 servo extensions...
washers for Down Right thrust...
Also... instead of using some of the kit parts... We decided to use metal wire and hobbycity snap connectors on every horn and servo arm... 8 total... Makes for zero slop... very nice...
We used epoxy on all the carbon fiber parts and foam glue with kicker for everything else...
Motor was mounted to the wood mount (drilled holes to fit) at the very end and then the mount was screwed to the firewall... esc and Dx6 Rx inserted in bottom, hole enlarged to fit my anderson powerpoles through to the top battery box...
This is the motor We used...very powerful for this application and the price is great, $6 an emax "fc 28-22 1200kv" running an apc 9x4e 13amps full throttle
http://www.hobbycity.com/hobbycity/s...runner__1200kv
servos used were hxt900's 3 of them...
800mah 20c loongmax battery... pulls about 13amps... will be using 1000 zippy 15c when they arrive...
AUW is about 12 ounces...
My aileron travel rates are 100% on everything 70% expo... This is my new favorite setting.... everyone who flew it on this setting liked it...
we used lower holes on horns for ailerons, middle for everything else, and farthest outer holes on the servo arms, for "Lots and Lots of travel" prob about 4-5 rolls a sec
One additional mod we did was to cut some of the flat Carbon Fiber about 2 inches and mount that to the bottom side force generators... this helps landings... because it hits that part first... so nothing gets chewed up... I find this to be a very important mod...
With this setup it make it about $55 for kit, brushless motor, supersimple brushless esc, servos, snap connector, servo extensions...
SK
Some Mods we did in the beginning paid off pretty good...
First, We Moved the servos much further back... I didn't like the idea of putting them that far forward, so we cut slots and mounted them one on each side and much further back... added 2 servo extensions...
washers for Down Right thrust...
Also... instead of using some of the kit parts... We decided to use metal wire and hobbycity snap connectors on every horn and servo arm... 8 total... Makes for zero slop... very nice...
We used epoxy on all the carbon fiber parts and foam glue with kicker for everything else...
Motor was mounted to the wood mount (drilled holes to fit) at the very end and then the mount was screwed to the firewall... esc and Dx6 Rx inserted in bottom, hole enlarged to fit my anderson powerpoles through to the top battery box...
This is the motor We used...very powerful for this application and the price is great, $6 an emax "fc 28-22 1200kv" running an apc 9x4e 13amps full throttle
http://www.hobbycity.com/hobbycity/s...runner__1200kv
servos used were hxt900's 3 of them...
800mah 20c loongmax battery... pulls about 13amps... will be using 1000 zippy 15c when they arrive...
AUW is about 12 ounces...
My aileron travel rates are 100% on everything 70% expo... This is my new favorite setting.... everyone who flew it on this setting liked it...
we used lower holes on horns for ailerons, middle for everything else, and farthest outer holes on the servo arms, for "Lots and Lots of travel" prob about 4-5 rolls a sec
One additional mod we did was to cut some of the flat Carbon Fiber about 2 inches and mount that to the bottom side force generators... this helps landings... because it hits that part first... so nothing gets chewed up... I find this to be a very important mod...
With this setup it make it about $55 for kit, brushless motor, supersimple brushless esc, servos, snap connector, servo extensions...
SK
Last edited by ministeve2003; 07-07-2008 at 08:08 PM.
#117

Ministeve and I bought one on the 4th on sale for $24.95 . It took about 10-12 hrs to build but we flew it today and he let many non-3Der flyers fly it . Every one who flew it looked like an expert 3Der when doing K E s. Here's a couple in flight shots. I read in this thread someone paid $15 for it .WHERE? Steve liked it so much we went back to Hobby Ppl and got 3 more 1 for a spare ,1 for me , and 1 for his buddy
http://www.hobbypeople.net/gallery/160532.asp
#118

I double checked, I was wrong on prop size... it was an apc 8x4e prop 13amps 140-145watts... motor comes down cool... although I rarely give it full throttle... its got plenty of power... hovers at just a scratch over half throttle...
SK
SK
#120

I really like it but I am starting to notice some weak spots.
The fuse wing strut upper and lower are starting to stress fracture. The landing gear doesn't hold up for very long. All of it is fixable but weak spots none the less.
I really think anyone with any experience could get a kick out of this plane.
Alpea, I like the mods you made but why move the servos back?
The fuse wing strut upper and lower are starting to stress fracture. The landing gear doesn't hold up for very long. All of it is fixable but weak spots none the less.
I really think anyone with any experience could get a kick out of this plane.
Alpea, I like the mods you made but why move the servos back?
#121

I really like it but I am starting to notice some weak spots.
The fuse wing strut upper and lower are starting to stress fracture. The landing gear doesn't hold up for very long. All of it is fixable but weak spots none the less.
I really think anyone with any experience could get a kick out of this plane.
Alpea, I like the mods you made but why move the servos back?
The fuse wing strut upper and lower are starting to stress fracture. The landing gear doesn't hold up for very long. All of it is fixable but weak spots none the less.
I really think anyone with any experience could get a kick out of this plane.
Alpea, I like the mods you made but why move the servos back?
Ps, It balances out perfect..
SK
#122

I agree, this plane does see like it might not last too many rough landings, but for $15, thats cheaper than going to the movies. Mine fell off a shelf I had it perched on and it took a nice 6ft tumble, but came out with only a broken aileron. Not bad I guess. A little CA and she's fine. I've done more damage to it in my living room than I have flying it. But I must confess, I haven't really had too many chances to fly her so far....
#123

I agree, this plane does see like it might not last too many rough landings, but for $15, thats cheaper than going to the movies. Mine fell off a shelf I had it perched on and it took a nice 6ft tumble, but came out with only a broken aileron. Not bad I guess. A little CA and she's fine. I've done more damage to it in my living room than I have flying it. But I must confess, I haven't really had too many chances to fly her so far....
SK
Did anyone else think to put a little cf strip on the bottom SFG? it'll really help if you slightly dip your wings on landing... nothing will get chipped up
#124

I would have to agree, when price and flight capability is compared to maintanence it seems like a no brainer.
I really need to buy a few more cause I am going to regret it when I destroy this one without having a replacment.
I really need to buy a few more cause I am going to regret it when I destroy this one without having a replacment.
#125

But I'm thinking if I could bring the Internet Add in and have it matched. I might buy 2 more... for "just in case"
SK