McFly

McFly

Well Known Member
I have $1.00 riding on the answer.

What is the maximum allowable HP of a LSA aircraft? Thanks.
 
I do believe there is no takeoff HP limit for LSA, but there is a 100HP cap on MAX CONTINUOUS power if I'm not mistaken.
 
osxuser said:
I do believe there is no takeoff HP limit for LSA, but there is a 100HP cap on MAX CONTINUOUS power if I'm not mistaken.
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Not aware of that requirement. There is a max weight (1320 lbs), max seats (2), max speed (120 knots), max stall speed (45 knots), no retracts (except for amphibious floats) and non flight adjustable prop (ground adjstable ok). I am not familiar with any HP restriction.

Try this link from EAA for an overview of the LSA requirements.
http://www.sportpilot.org/learn/aircraft_index.html
 
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RVbySDI said:
Not aware of that requirement. There is a max weight (1320 lbs), max seats (2), max speed (120 knots), max stall speed (45 knots), no retracts (except for amphibious floats) and non flight adjustable prop (ground adjstable ok). I am not familiar with any HP restriction.
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Why do I have the feeling that the first time somone tries to get their brand new "Greasy Weasel", powered by a "derated" IO-540, certified as a LSA at 1320 #'s and 120 kts cruise, the Fed's are going to open up that discussion? :D
 
ddurakovich said:
Why do I have the feeling that the first time somone tries to get their brand new "Greasy Weasel", powered by a "derated" IO-540, certified as a LSA at 1320 #'s and 120 kts cruise, the Fed's are going to open up that discussion? :D
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This is an interesting thought. I have heard a story (third hand at least so not sure to believe it or not) of a guy who put a jet engine on a part 103 ultralight. It met all of the legal requirements for weight, etc. for the ultralight but was powered by a powerful small jet engine. I am sure that scared the beegezus out of some FAA bureaucrat! :p
 
RVbySDI said:
This is an interesting thought. I have heard a story (third hand at least so not sure to believe it or not) of a guy who put a jet engine on a part 103 ultralight. It met all of the legal requirements for weight, etc. for the ultralight but was powered by a powerful small jet engine. I am sure that scared the beegezus out of some FAA bureaucrat! :p
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True story, he even brought it to OSH a few years back.

As for the HP question...

Last night at our EAA 309 chapter meeting we had an LSA instructor as a guest speaker and his answer was that there is no limit on LSA HP. Just GRW, # of seats, stall speed, etc.
 
N941WR said:
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As for the HP question...

Last night at our EAA 309 chapter meeting we had an LSA instructor as a guest speaker and his answer was that there is no limit on LSA HP. Just GRW, # of seats, stall speed, etc.
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While it is strictly correct that no maximum horsepower is explicitly stated in the LSA regs, the horsepower is in fact limited due to the requirement that you cannot exceed 120 kts when running at the engine's rated maximum continuous power. I imagine an arbitrary derating of a large engine by a builder will push the spirit if not the letter of the reg.
 
Jabiru has already pushed it with their 3300 I believe in a couple of the LSA... It does 120 knots at an artificially low max continous power setting.
 
Answer to the original question. There is NO horse power limitation for Light-Sport aircraft. Only a maximum speed at "maximum continuous hp".
 
It depends on the airframe...

osxuser said:
Jabiru has already pushed it with their 3300 I believe in a couple of the LSA... It does 120 knots at an artificially low max continous power setting.
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The speed you get out of a J3300 will totally depend on the airftame. I've been flying the IndUS / Thorpe T-211 "Thorpedo", which uses the J3300 and a Sensench wood prop. The only way it will hit 120 kt is with full power in a dive. Don't get me wrong - it's a nice airplane, but it has a LOT of drag. Opening the canopy in flight doesn't help much with the speed either, but it helps with stayng cool on those 100+ days...

(Summers in TX make me want to build a Breezy!)
 
osxuser said:
Jabiru has already pushed it with their 3300 I believe in a couple of the LSA... It does 120 knots at an artificially low max continous power setting.
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I don't think Jab is limiting the RPM of it's engine for the purpose of LSA rules or sales. That engine on the right airframe would do a lot more than 120kts.
 
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