Burt Rutan’s Boomerang – Safety Through Asymmetry
wired.com
wired.com
They deliberately make them unstable and can then utilize that to make turns that are sharper than otherwise possible. The drawback is that they have to be controlled by computers all the time. This led to a spectacular crash in Stockholm in 1993 where luckily nobody was hurt.
If you can change between maneuvers faster than your adversary you can cause him to be confused, giving you the advantage. This all comes from energy maneuverability theory which is the theory that modern fighters are based on.
Build planes capable of fast transients and a natural buttonhook tendency.
This wikipedia article is certainly relevant http://en.wikipedia.org/wiki/Critical_engine but I'm still not sure how the Boomerang can be so stable that it requires no rudder input during takeoff.
My guess is that by having one engine further back he creates the equivalent of the dihedral effect. If the plane starts to yaw in one direction. I have nothing but intuition to support this idea :)
I would love to see a detailed explanation of how this plane is so stable.
I instinctively look for symmetry in my designs (and my purchases too I suspect).
I wonder if the reason it never 'took off' commercially was that people instinctively disliked the lack of symmetry?
> Like many of Rutan’s creative designs, the Boomerang never went
> into production. There was never even a second example built.Is this really that unusual? In the Bulldog (which is very small and single-engined) you can get away with not using the rudder at all during normal flight.
Edit: Asked a friend who knows these things, it's not that unusual for a twin engine to not need a lot of rudder, but also not a rule either.
couldn't you do even better with a push-me pull-me configuration? then power would always be aligned correctly, whatever failed. perhaps that is less efficient, since the pusher is in the wake of the puller? it wouldn't look so fugly...
For example, the Blohm and Voss BV141, an experimental German aircraft, used an asymmetric single engine design wherein the weight asymmetry was balanced by the prop torque, which tends to cause yaw and generally needs to be trimmed out on non-counter-rotating twins and single engine airplanes. [0]
With regard to push-pull config: the Cessna Skymaster was designed this way. There are about 3000 of them flying around, including about 500 in military service, according to Wikipedia [1].
Another amazing aircraft design that never caught on and had some of the enhanced stability properties inherent in closer engine placement was the Beechcraft Starship [2]. For my money, it's the most beautiful business aircraft ever built, and it's got some seriously amazing aerodynamic features. For example, since it uses a canard design, it's very hard to stall: the canards will stall before the wings, which drops the nose, decreasing AoA and increasing lift.
There's an amazing image of a Starship chasing a SpaceShipOne during a test flight on the Wikipedia page.
[0] http://en.wikipedia.org/wiki/Blohm_%26_Voss_BV_141