Because two blades are faster in cruise than three. All propellers have induced drag as a spinning mass. When you add an extra blade to the equation, drag increases. This all depends on a lot of situations though. If you can’t utilize horsepower and turn it into thrust, either pitch needs to increase or more blades need to be added as the critical angle of each blade is reached. This is why a 3 or more blade prop will have better takeoff performance, they turn a fine pitch to develop max thrust at slower speeds. As relative wind increases, so does drag. I went to a 3-blade on my Comanche 250 and lost about 3-5kts on the top end, but I noticed a lot better takeoff ground roll.
Bill, what do you mean by flair speed of 120 kts? According the the POH final is flown at 83 kts. Also I think the benefit of the high wing loading is smoother turbulence penetration, what do you think? Dan
I must have missed something. I thought you said unfortunately, it falls like a rock if you have an engine failure and then you said but it has a fantastic glide ratio if you have an engine failure. Which is it?
Both. According to the manual, power off, you can expect a rate of descent of ~1500 feet per minute. Best glide speed is 140mph. The math works out to an 8:1 glide ratio, which is respectable for a propeller powered aircraft. So, although you are coming down quite quickly, you are covering a lot of ground on the way down.
"Not for the low time pilot". That sayes it all! Most of the old timers think anyone with less then a full 1000 hours of PIC time is; "Just a beginner"!
Did you say topspeed was 240 Knots? Thats impressive. The shortwinged got a carry load of 29 pounds pr. squarefoot, but how much load did you say you get pr. squarefoot from the long winged one? Sorry, Im from Norway. Think Im loosing my hearing to. Angle of attack/ or did you say "a tankmeter", like a "whats left of fuel"-measurer??? Strikefinder??? Nice plane, normal prizerange?
+-eivind Ottar He said 27 pounds per sq ft for long wing. You can activate closed captioning on this video and it will do its best to write everything in subtitles.
this plane flairs around 70 or so knts . the super ii is probably the best personal plane available! long wing stalls at 63 and cruises all day at 220+. range about 1500 to,1700 miles two plus bags! no tsa and long lines.beat the airlines on any trip under 700 or so miles! the iii is overkill!
How could these planes be considered dirty when they have no external stores to impede the airflow. They should always be in a clean configuration except to land with flaps and landing gear.
"Dirty" means flaps down/gear down in a retractable gear aircraft. Therefore planes are said to have a "clean" and "dirty" stall speed. In a fix gear aircraft "Dirty" means adding flaps.
in Military flying you are right on, Dirty would expand from flaps/gear to any external stores such as bombs/drop tanks etc. I think the word refers to external drag creation elements that can be "cleaned" up by flight crew action (raise the gear, raise the flaps, drop the bombs/tanks). So that aircraft have performance parameters in a "clean" and "dirty" configuration. Aircraft which have non removable (by cockpit action) external elements that cause drag (antennas, lights, whatever) can definitely be said to "dirty" up the aerodynamics of the plane. Take a look at a picture of an ME109, I would say that is aerodynamically "filthy" : ) . A Glasair III is definitely *NOT* aerodynamically dirty in clean configuration, under power. I do wonder what the glide ratio is with a windmilling prop though. That number compared with various things like a Cessna/Piper/Mooney would tell you how relatively good it is in the gliding department.
I haven't heard of "flair speed" either. I even took the time to Google it and still didn't find anything. I guess flair speed is what it sounds like -- it's when you flair. Maybe you flair at 120 kts and land at 83 kts? If so, things would be moving along pretty quickly! Either way, it's no C-172, that's for sure.
I don’t know Bill. Sounds like you have contradicted yourself on the engine out characteristics. ANY constant speed prop will initially produce high descent rates with a loss of thrust until it is feathered. If you clean up the airplane it glides better. Yep. Nothing new here. No idea what you are talking about with the 120 knot “flair” speed? A higher wing loading produces a nice ride in the bumps. The approach and stall speed on the G3 are not beyond the scope of any Bonanza or Mooney pilot. The higher wing loading will produce a high sink rate if you get slow………so low and slow in this airplane is not where you want to be. Same with any airplane. Finally, your head darting around looks like you are dodging throwing knives or something.
Bill you are an inspiration!
I always wondered why high performance airplanes like the Glasair have 2 bladed props instead of 3. Can someone pls explain that?
Because two blades are faster in cruise than three. All propellers have induced drag as a spinning mass. When you add an extra blade to the equation, drag increases. This all depends on a lot of situations though. If you can’t utilize horsepower and turn it into thrust, either pitch needs to increase or more blades need to be added as the critical angle of each blade is reached. This is why a 3 or more blade prop will have better takeoff performance, they turn a fine pitch to develop max thrust at slower speeds. As relative wind increases, so does drag. I went to a 3-blade on my Comanche 250 and lost about 3-5kts on the top end, but I noticed a lot better takeoff ground roll.
Bill, what do you mean by flair speed of 120 kts? According the the POH final is flown at 83 kts. Also I think the benefit of the high wing loading is smoother turbulence penetration, what do you think?
Dan
I must have missed something. I thought you said unfortunately, it falls like a rock if you have an engine failure and then you said but it has a fantastic glide ratio if you have an engine failure. Which is it?
Both. According to the manual, power off, you can expect a rate of descent of ~1500 feet per minute. Best glide speed is 140mph. The math works out to an 8:1 glide ratio, which is respectable for a propeller powered aircraft. So, although you are coming down quite quickly, you are covering a lot of ground on the way down.
He's the Chuck Norris of Aviation!
"Not for the low time pilot".
That sayes it all! Most of the old timers think anyone with less then a full 1000 hours of PIC time is; "Just a beginner"!
Did you say topspeed was 240 Knots? Thats impressive. The shortwinged got a carry load of 29 pounds pr. squarefoot, but how much load did you say you get pr. squarefoot from the long winged one? Sorry, Im from Norway. Think Im loosing my hearing to.
Angle of attack/ or did you say "a tankmeter", like a "whats left of fuel"-measurer???
Strikefinder???
Nice plane, normal prizerange?
+-eivind Ottar He said 27 pounds per sq ft for long wing. You can activate closed captioning on this video and it will do its best to write everything in subtitles.
this plane flairs around 70 or so knts . the super ii is probably the best personal plane available! long wing stalls at 63 and cruises all day at 220+. range about 1500 to,1700 miles two plus bags! no tsa and long lines.beat the airlines on any trip under 700 or so miles! the iii is overkill!
No....will "cruise all day at 240 knots". TOP speed is around 262 knots....
He said with no power it drops like a rock and then says it has a great glide ratio with gear up. I am confused.
Clarify that sinks like a rock "dirty" and has decent glide ratio clean.
How could these planes be considered dirty when they have no external stores to impede the airflow. They should always be in a clean configuration except to land with flaps and landing gear.
"Dirty" means flaps down/gear down in a retractable gear aircraft. Therefore planes are said to have a "clean" and "dirty" stall speed. In a fix gear aircraft "Dirty" means adding flaps.
I always thought dirty meant bombs, antennas, sensors and other appendages on the aircraft. Thanks for the info.
in Military flying you are right on, Dirty would expand from flaps/gear to any external stores such as bombs/drop tanks etc. I think the word refers to external drag creation elements that can be "cleaned" up by flight crew action (raise the gear, raise the flaps, drop the bombs/tanks). So that aircraft have performance parameters in a "clean" and "dirty" configuration. Aircraft which have non removable (by cockpit action) external elements that cause drag (antennas, lights, whatever) can definitely be said to "dirty" up the aerodynamics of the plane. Take a look at a picture of an ME109, I would say that is aerodynamically "filthy" :
) . A Glasair III is definitely *NOT* aerodynamically dirty in clean configuration, under power. I do wonder what the glide ratio is with a windmilling prop though. That number compared with various things like a Cessna/Piper/Mooney would tell you how relatively good it is in the gliding department.
Makes him look tall.
I haven't heard of "flair speed" either. I even took the time to Google it and still didn't find anything. I guess flair speed is what it sounds like -- it's when you flair. Maybe you flair at 120 kts and land at 83 kts? If so, things would be moving along pretty quickly! Either way, it's no C-172, that's for sure.
I don’t know Bill. Sounds like you have contradicted yourself on the engine out characteristics. ANY constant speed prop will initially produce high descent rates with a loss of thrust until it is feathered. If you clean up the airplane it glides better. Yep. Nothing new here. No idea what you are talking about with the 120 knot “flair” speed? A higher wing loading produces a nice ride in the bumps. The approach and stall speed on the G3 are not beyond the scope of any Bonanza or Mooney pilot. The higher wing loading will produce a high sink rate if you get slow………so low and slow in this airplane is not where you want to be. Same with any airplane.
Finally, your head darting around looks like you are dodging throwing knives or something.