Just curious/interested and thought it would be fun to talk about. Lots of bipes popping up. Is it really worth it? What are the benefits?

Here's what I've been thinking about:

1) Drag: obviously more drag. Good for controlled speed, but would need more power or bigger batteries.

2) Weight: hard to imagine they don't weigh more, especially if you need bigger batteries or bigger motors
3) Airfoils: really could be tons of subtopics:

3a) Wing loading: what's the benefit of lighter wing loading? I've had a pattern plane with a fairly big wing and hated how light it felt on the wing. However I don't fly 'complicated' rolling maneuvers. Does the light wing loading help transition the lift from the wing to the fuse during rolls? Is the light wing loading a big benefit to snaps?

3b) Incidence: another thing to adjust. From a theoretical standpoint I'm not a big fan of adding airfoils to a plane, yet. It seems to me that adding an airfoil that is not perfectly aligned will have some fairly significant impact. Bipes have double the need for paying attention to incidence, washout, aileron deflection, dihedral, etc. If a warped rudder can screw up how a plane flies, I can hardly imagine what a poorly setup bipe (or plane with canalizers, winglets, etc) would do.

3c) Sheer: generally there is some decent space between the wings, but recent pattern planes show the wings getting closer together. I imagine theres going to be a sheer effect at some point.

I almost took a job in airfoil design - I could dream about this crap all day. Didn't seem like the best move for my career though, so it fell to second choice.

I think you missed the main point: They go sideways better.

Power isn't an issue for IC. I started flying 5kg, 2m models with a YS FZ140. Now i'm using the YS DZ175cdi and still 5kg.

The DZ185cdi is more powerful again and the models are still 5kg. Power to burn.

Having not flown a bipe pattern ship yet, i don't know what benefits they have over a mono plane, but they cerainly look cool.

Hi Joe,

Some good points. Weight and complexity are definite concerns but I am watching the Bipe evolution very carefully, Remember what is needed in FAI is not what is needed for all the other classes. Take a close look at the F13 schedule and plan out the pace needed to keep it in the box at 150 meters. Then do the same for F15 and finally look at the unknown catalog. The KE cuban eight in unknowns at this years Nats left a lot of pilots wishing for a slower pace and more KE authority. Lots of skidding and misshapen maneuvers.
Drag is a factor but the wings are smaller in chord, span and cross section increasing there efficiency. Deep in the Biside thread there is BJ mention of how efficient the plane is. Gerhard (sp) is also using 1kg batteries in the Trigantic which probably puts them around 3500 mah. All of the comments I have seen about it are positive despite the very high winds. Wing loading is very noticeable when transitioning from verticals to horizontal. The plane locks into a line much more easily and with less power. Flying a heavily loaded plane requires more driving it into each line than flying.
Having followed Jim Kimbro at Muncie I really think that their design is one of the best bipes I have seen. The pace and rudder authority that plane presents are great. Both flew it well and it looks like a winner. Was very disappointed when I was told they wouldn't be available. I keep asking Bryan for an E - Alferma but he keeps talking about some prior commitment. Also, very disappointed I missed the opportunity to get a ride on a Biside.

Bipes present better IF the flight is good but Bipes also show a pilot's mistakes more. Unfortunately, this pilot has "bipe fever" really really bad right now.