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Ligeti Stratos – First Open Source Microlight Aircraft (2013)
- serf 6y agovery cool design, one of the few airframes that can gain altitude without pitching up -- this is an important safety feature as it reduces chance to stall. On the flipside, though, stalling a Ligeti Stratos is probably a major event since it's almost a flying-wing.
- StavrosK 6y agoFlying wings stall just fine, what makes you think otherwise?
- sokoloff 6y agoGiven the original designer was killed by stalling it on approach to land, I’d say the safety benefit is unproven at best.
- burlesona 6y agoWait, the designer of this plane died landing it?
- sokoloff 6y agoYes. “During a short test flight of the new highly modified production version in September 1987 the airplane stalled during approach to landing and Charles Ligeti was killed.” [0] http://ligeti-stratos.com/history.html http://ligeti-stratos.com/history.html
- FlyMoreRockets 6y agoNo, different plane. “During a short test flight of the new highly modified production version"
- sokoloff 6y agoIt was a modified version of the prototype upon which the current efforts are based. That’s not cleanly “exactly same” nor “totally different” airplane design, but the mishap airplane was clearly closer to this effort than to a 172.
- p_l 6y agoRemember that stalling is related to angle of attack of the wing and the speed. You can stall in a dive, even (it's hard, though :D) In fact, all planes can gain altitude without pitching up, by increasing speed, and by decreasing speed can lower altitude. The resulting lifting force on the wings is for most important flight regimes a function of speed and angle of attack.
- gabereiser 6y agoThis is taught in basic flight school. Power is lift, not pitching up.
- p_l 6y agoThe things that are covered in first chapters of flight theory textbook for pilots, but which confound otherwise very knowledgeable laymen, can be summarised as close to all of them ;)
- TeMPOraL 6y agoAny recommendations on the books? Because I'm definitely confounded. I assume that AoA=0 and flat wing (not a teardrop-shaped one) would not lift off despite increasing the engine power (assuming no wind). Is that correct? I'm very much confused by what you're saying - given that "lifting force on the wings is for most important flight regimes a function of speed and angle of attack", isn't it easier to change the AoA, by operating the control surfaces and pitching the plane, instead of adding or reducing speed?
- TylerE 6y agoIn takeoff and landing, the most critical phases of fight, the range of useable pitch is fairly narrow... too much and you bang the tail into the ground. Too little and you strike the prop. The way you’re taught to land you use the controls is basically backwards - the elevators (pitch) control speed. The throttle controls rate of descent.
- 6y ago
- intrepidhero 6y agoI'm not sure "open sourcing" a major piece of hardware (like an airplane) has a lot of meaning. Kit plans for experimental aircraft are pretty easy to get for a few hundred bucks. But your still thousands of dollars and hours away from having an airplane. It's a pretty thing for sure. And I think it's neat they want to give away plans. Just don't think it's a big impact.
- sokoloff 6y agoOpen sourcing plans allows for others to modify the plans and for the community to improve them in a way that closed-source, cheaply-sold plans do not. Open source is about more than price.
- burlesona 6y agoWell, in response to Sokoloff’s comment below I did some more reading (the history tab on the linked site), followed by googling. Turns out the designer of this plane died in a crash while testing it. I found a crash report here: http://aviation-safety.net/wikibase/217844 http://aviation-safety.net/wikibase/217844
- FlyMoreRockets 6y agoNote: the prototype is open sourced, not the production plane. From the linked article: "This [crashed] aircraft was intended to be the production version of the "Stratos" aircraft. The prototype version had successfully flown some 340 hours. The production model incorporated significant changes made by the designer/pilot."
- nkingsy 6y agoAren’t the microlight planes about as dangerous as a wing suit?
- nikitaga 6y agoNo. But: Test-flying unconventional prototype / experimental airplanes, or flying commercially available ultralights? With or without training? And wingsuits – proximity flying? base jumping? Or just jumping out of a plane? The risks of those scenarios are magnitudes apart. Personal aircraft are about as dangerous as motorbikes. Base jumping on the other hand, whether with a wingsuit or not, is one of the most dangerous recreational activities you can do, with a fatality rate of something like 1% per participant per year.
- jackyinger 6y agoIn a tandem wing configuration like this it is unwise to make the forward wing the low one. This is because at high angles of attack (think takeoff, landing, low speed flight, climbing) the rear wing will end up in the “dirty” turbulent wake of the first wing. Wings are much more efficient in “clean” smooth air. The lower lifting efficiency in situations where you need high lift (see previous list of high angle of attack settings) makes a design dangerous. If you’re interested in this sort of stuff, this is the best book I’ve found on the subject, it is very practical and written with the engineering minded amateur designer in mind: https://www.amazon.com/Design-Aeroplane-2e-Darrol-Stinton-dp-0632054018/dp/0632054018/ref=dp_ob_title_bk https://www.amazon.com/Design-Aeroplane-2e-Darrol-Stinton-dp...
- kashkhan 6y agocheck out Quickie and Q2 https://en.wikipedia.org/wiki/Rutan_Quickie https://en.wikipedia.org/wiki/Rutan_Quickie t tails on most business jets etc.
- jackyinger 6y agoThere are certainly successful exceptions to this rule. In the see exceptions I’m sure that the engineering was done to mitigate the risk. For instance with T tails, the designer would hopefully either place the elevator high enough to be out of the dirty air, or do the analysis to make sure it functioned well in he dirty air.
- baybal2 6y agoRutan Quickie is subject to deep stall, and it has an AOA never exceed limit because of it.
- kashkhan 6y agoall configurations have advantages and disadvantages. Most civilian jets have tails which are mounted higher than the main wing. The position matters when you are talking about not getting into stall and then recovering from a stall. A lower tail is definitely better for an inexperienced pilot or a pilot in a bad situations. And the safety records of high wing planes like Cessna 172 speak to that.
- baybal2 6y agoI had a childhood dream of building my own moto-glider. I managed to advance to an unpowered glider, but without a motor, and no chance to get a tow from anybody. I managed to take off once, for a few meters from a slope, and that was it. Once I hit 16, I had to leave Russia, and the unpowered glider parts still lie in my uncle's garage.
- wankeler 6y agoLooks awfully close-coupled
- basicplus2 6y agoLooks like a powered modified box kite