Aircar
Well-Known Member
Until just a few days ago I had not read the detail on the rules for LSA aircraft under the US rules and only peripherally followed the stories for and against LSA aircraft or whether or not it has flopped or expanded .
One provision that caught my eye was the limitation to just ONE engine (ruling out hybrid power apparently and the idea of a back up electric motor or even I suppose on board recharging by gasoline engine --for example the Rutan BiPod -- I can see why wing mounted twins might be restricted from at least initial relaxed training and operation standards (the assymetrics and control loss issue ) but not why any 'standby' second motor should be excluded on safety grounds .
The second thing was the prohibition of "lift enhancing devices" (even if the stall speed without such use was still below 51mph (itself an absurd figure --related to "51"% construction perhaps ) --is this a correct interpretation ? (and again no retractable landing gear except for a glider -- are these provisions anywhere justified ?
The Terrafugia roadable was unflapped and displayed attrocious take off and landing ability yet seems to meet the letter of the law --it seems to be an inherently bad specification if it sets a maximum full throttle airspeed and thereby penalizes a clean aircraft to have a higher power loading (more pounds per horsepower ) and hence a lower climb rate than a lighter but draggier design. seems like a bad specification .(as nearly always results from specifying arbitrary design limits or criteria which both limit competition (or unreward improvement) and define a bad result much like the original Australian ultralight category which specified a 400lb aircraft plus pilot plus fuel AUW and a 4lbs per sq ft wing loading (and a max height of 400 ft plus no crossing of made roads etc ) --later admitted to be set because there were no aircraft of that specification in existence (or Janes' all the worlds aircraft at least )
What has been experience so far with the LSA category from a design viewpoint.?
One provision that caught my eye was the limitation to just ONE engine (ruling out hybrid power apparently and the idea of a back up electric motor or even I suppose on board recharging by gasoline engine --for example the Rutan BiPod -- I can see why wing mounted twins might be restricted from at least initial relaxed training and operation standards (the assymetrics and control loss issue ) but not why any 'standby' second motor should be excluded on safety grounds .
The second thing was the prohibition of "lift enhancing devices" (even if the stall speed without such use was still below 51mph (itself an absurd figure --related to "51"% construction perhaps ) --is this a correct interpretation ? (and again no retractable landing gear except for a glider -- are these provisions anywhere justified ?
The Terrafugia roadable was unflapped and displayed attrocious take off and landing ability yet seems to meet the letter of the law --it seems to be an inherently bad specification if it sets a maximum full throttle airspeed and thereby penalizes a clean aircraft to have a higher power loading (more pounds per horsepower ) and hence a lower climb rate than a lighter but draggier design. seems like a bad specification .(as nearly always results from specifying arbitrary design limits or criteria which both limit competition (or unreward improvement) and define a bad result much like the original Australian ultralight category which specified a 400lb aircraft plus pilot plus fuel AUW and a 4lbs per sq ft wing loading (and a max height of 400 ft plus no crossing of made roads etc ) --later admitted to be set because there were no aircraft of that specification in existence (or Janes' all the worlds aircraft at least )
What has been experience so far with the LSA category from a design viewpoint.?