Burt Rutan’s Boomerang – Safety Through Asymmetry
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Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#2Reminds me of the beautiful control theory concept of relaxed stability (http://en.wikipedia.org/wiki/Relaxed_stability). You intentionally craft instability in the system and use a controller to manipulate and exploit it, seemingly gaining extra performance for little cost. Unfortunately this doesn't even begin to scratch the surface of control theory but it's a neat introduction to an interesting branch of mathematics/engineering most CS people aren't aware of.
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#3i think this must be more stable largely because the two engines are closer together (effectively one "side boom" is moved to the centre).
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...
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#4Another beautiful piece of non-obvious design.
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?
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#5Another beautiful piece of non-obvious design. 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?
It seems like it didn't take off commercially because it was just never pursued:
> Like many of Rutan’s creative designs, the Boomerang never went
> into production. There was never even a second example built.Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#6This is the kind of mechanical device where I could support patents, especially for a ~5-10 year span.
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#7i think this must be more stable largely because the two engines are closer together (effectively one "side boom" is moved to the centre). 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...
I'm pretty sure there's more to it than just that. For example, the difference in power output between the two engines wouldn't be necessary if the enhanced stability were due only to reduced distance between engines.
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
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#8his another asymmetric http://stargazer2006.online.fr/aircraft/ares.htm
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#9i think this must be more stable largely because the two engines are closer together (effectively one "side boom" is moved to the centre). 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...
Yup, he built that too:
http://en.wikipedia.org/wiki/Rutan_Defiant
Re: Burt Rutan’s Boomerang – Safety Through Asymmetry
#10Reminds me of the beautiful control theory concept of relaxed stability ( http://en.wikipedia.org/wiki/Relaxed_stability ). You intentionally craft instability in the system and use a controller to manipulate and exploit it, seemingly gaining extra performance for little cost. Unfortunately this doesn't even begin to scratch the surface of control theory but it's a neat introduction to an interesting branch of mathem…
I believe that's how modern fighter jets are designed, for exmaple JAS 39 Gripen http://en.wikipedia.org/wiki/JAS_39_Gripen
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.