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Dec 14, 2005, 08:21 AM
Crash Master
Gene Bond's Avatar
Build Log

4-S Bipe, sorta-Soma / sorta-Sym

This is the hybrid I came up with between my Sym-Bipe (symetrical, but fishy looking) and TOG's Soma-Bipe. I stole his lines and wiggled and warped until it sorta fit my Sym-Bipe planform, and looked like a plane

I stopped at EWO's yesterday, and we both got a chance to fly it:

Here's some pictures and plans, have at it!

4-S Bipe final specs:

Motor: 22.7mm single CDR (GBv) 20t/26g
Prop: 8040HD
Motor Test: 10v, 5.8a, 8200rpm, 11.22oz, 58w, 31mph
Battery: 3s340
AUW: 7.8oz
Span: 23"
Length: 29"
Wing Area: 370sqin
Wing Loading: 3oz/sf
Power: 120w/lb


edit: a 4SBipe kit is now available:
Last edited by Gene Bond; Mar 12, 2006 at 07:34 AM. Reason: Videos relocated
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Dec 14, 2005, 08:32 AM
“There’s no place like Foam”
gpw's Avatar
Yahoo!!! Just in time !!!!! Yipee!!!!!
Many Thanks ,Gene.... we've been waiting for just the right bipe to come along and this is IT !!!!!!! CD powered , not to big .... just PERFECT !!!!

Named after that town in Ca. Alta Coma....????
Last edited by gpw; Dec 14, 2005 at 08:39 AM.
Dec 14, 2005, 09:51 AM

Is there a reason for making each wing in two pieces? I'm probably gonna feel really stupid when you tell me, but I had to ask.

edited: nevermind, I'm an airhead. There not in two pieces! I went back and looked at the pics.
Last edited by gravitygust; Dec 14, 2005 at 01:33 PM.
Dec 14, 2005, 10:57 AM
I have beef with no man
Flappers's Avatar

Your timing is impeccable!!!

I've just finished building, triming up, my latest project (another bi plane, ooh that'll be my 6th so far), had a successful maiden this lunch time for about 40 minutes. I returned to work feeling slightly down as I now have nothing to tinker with this evening only to stumble accross this thread . Boy I love free plans!!!

Thanks for sharing

Great looking plane bi the way

Dec 14, 2005, 12:57 PM
Crash Master
Gene Bond's Avatar
gg: I only draw 1/2 of the symetrical surfaces, such as the wing, H-tail, and crutch... I cut the template, and use some masking tape as a hinge to cut the part on the foam. I cut one side, and then flip it over using the hinge and cut the other 1/2.

Hmmm.. Maybe I need to post a picture of that?

Of course, you could just print 2 sets of theose pages and tape them together...
Dec 14, 2005, 01:07 PM
Crash Master
Gene Bond's Avatar
Flap: This is somewhere around the 15th Bipe I've built Not all 3d, but it's the best I've got yet! ( and yet sure is a relative term!)

watch the weight and you'll be OK

Note that I peeled the skin off the fan fold, and there is no bracing. At this weight, it doesn't need it... Start using heavier equipment and it's suddenly a different animal! 3mm depron should work as well (and save more weight), but may need a hair of bracing, like maybe a doubler on one side of each wing (a strip about 1.5" wide, 1-1.5" back from the LE, and 70-80% of the span).

For you guys who don't build motors, there are several sources, not the least of which would be a Len's 20t motor which shold perform exactly as mine.

I used Cheap TP-50 servos, and extended the arms on the elevator and ailerons last night. I used some scraps cut off GWS arms, a drop of CA and a little bit of floss (and kicker ) Picos / HS-55's, BB306, etc should be fine.

Kokam 340-360 and MaxAmps 380's have been used and work well.

*** Balance is important ***
Hang the plane from the prop on a string from the ceiling (with battery and all ready to fly), and see if it leans one way or the other. Try to move whatever you can around so it is as close to balanced vertically and horizontally as you can.... Symetry!

Hope to hear how it goes!
Dec 14, 2005, 01:25 PM
Got it Gene..thanks. I've been doing the "print 2" thing.

Do you have any close up images of the control linkages? Especially the aileron linkage setup. A picture is generally worth a 1000 words. As I get older, they're worth more like 2500 words!

Are you just bending to attain proper adjustment? I wonder how effective the ailerons would be on just one wing? I've not done a bipe yet.
Last edited by gravitygust; Dec 14, 2005 at 01:32 PM.
Dec 14, 2005, 03:05 PM
__Jackass Savant__
theBOZman's Avatar
Originally Posted by Gene Bond
Hang the plane from the prop on a string from the ceiling (with battery and all ready to fly), and see if it leans one way or the other. Try to move whatever you can around so it is as close to balanced vertically and horizontally as you can.... Symetry!
wow. Interesting idea. I would think it would hang straight even if it's off balance. Thanks for the tip!

I have a few 278's and 283's needing homes. If I was to use them, what size WS would you recommend Gene?
Last edited by theBOZman; Dec 14, 2005 at 05:09 PM.
Dec 14, 2005, 06:47 PM
Crash Master
Gene Bond's Avatar
gg: closeups added.

Boz, I think 28-30" would be about right for a heavier one. I'll work on scaling it up some. I knew the request would come
Dec 14, 2005, 07:07 PM
Registered User
ewo's Avatar
Hey Gene !
Thanks for those plans man .I printed them out at noon and just finished cutting them out. Ill cut the foam tonight

Im probably going to use the little purple motor i showed you yesterday, not shure just yet. i do have a really good 17 turn cdrom i might use

Thanks again!

Dec 14, 2005, 07:07 PM
__Jackass Savant__
theBOZman's Avatar
I've already scaled it. Should I post it????

Thanks for the recommendation!
Last edited by theBOZman; Dec 14, 2005 at 07:21 PM.
Dec 14, 2005, 07:29 PM
Birdchased's Avatar
My daughter and I both agree, it looks like a Guppy with wings. Although I personally think the nose looks alot like Snoopys, as well. Painted as such, it would make a great Snoopyhead Bipe!
Dec 14, 2005, 07:46 PM
Crash Master
Gene Bond's Avatar
Boz: go for it!

BC: Man, and I tried NOT to make it look like a fish And I already did a Beagle... darnit! I see both of them now that you said it...
Dec 14, 2005, 08:00 PM
__Jackass Savant__
theBOZman's Avatar

Here's Gene's 4S resized to 30 inch for you guys.....

Thanks again Gene. I've been waiting for a good Bipe.
Dec 14, 2005, 08:01 PM
“There’s no place like Foam”
gpw's Avatar
Something fishy about this whole bipe business....
Latest blog entry: Lost plans

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