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I was looking for a thread summarizing STOL performance and slow flight, without success, so this could be such a thread.
We had a run of clear and calm mornings lately, so while out flying, I took the opportunity to do some slow landings to re-confirm the STOL performance of our Bearhawk 4-place. With the aircraft modestly loaded, around ¼ fuel and one person, the Bearhawk was running out of lift at ~37 kts GS (almost stalled) and touching the ground at ~33 kts GS allowing a half-second for measurement. Approaches can easily be flown below 40 kts indicated and GS. I'll explain the method below.
As a preface, this was an opportunistic performance check for interests sake, not a pre-planned exercise. So hold any questions on experiment design - this is only a practical check. My method was rounding out and holding off during the flare using a small amount of additional power, and using the GPS speed to confirm slow flight speed at steady-state pre-touchdown. I did landings on several different different vectors (the vectors are arranged in a triangle) to help identify the effect of any imperceptible breeze. All landings considered, it seems the practical results are +/-1 knot. Ambient conditions were about 200 ft AMSL, with temperature and pressures approximately at ISA for that altitude - which was convenient!
It’s hard to fly an aggressive STOL landing safely, with eyes inside the cabin monitoring speeds, while holding the aircraft at steady state pre-touchdown. Holding it a couple of feet off the ground, in other words. For that reason I didn't do an aggressive STOL landing, just an "average" STOL landing with a small margin for safety. So these results are not the best possible result, like you would expect in a STOL contest scenario. The plane can certainly land slower if pushed to the limit.
Note that our aircraft has extended hoerner wingtips fitted, not the common rounded wingtip.
So to summarise:
Approaches 38 kts
Rounding out / flaring at 37 kts
Touchdown somewhere just above 33 kts, without pushing it too hard.
Of course the safety caveat - each homebuilt aircraft is different, has different performance characteristics, and air conditions do vary. Please fly to the ambient conditions and your own aircraft's limits!
I think this is awesome performance for an honest 4-place aircraft.
Over the years, the 4-place has certainly allowed us to keep up with Super Cubs, in terms of landing on the shortest gravel bars etc. Given the high cruise speed and low-end STOL performance, it's hard to beat.
The best fun is had when very lightly loaded, with a cold high pressure morning, and a steady headwind. The plane can do some truly amazing things on those special days. For instance, a 30% climb angle with decent headwind is practically achievable from a standing start - measured over the ground, not through the air. Again, this is about practical or "useful" STOL performance, rather than a highly accurate measured result. Being able to land two full grown men and a decent load gear in a 60 metre (200 ft) space is a lot of fun, and challenging. Lately this has proven useful, on a couple of occasions.
We had a run of clear and calm mornings lately, so while out flying, I took the opportunity to do some slow landings to re-confirm the STOL performance of our Bearhawk 4-place. With the aircraft modestly loaded, around ¼ fuel and one person, the Bearhawk was running out of lift at ~37 kts GS (almost stalled) and touching the ground at ~33 kts GS allowing a half-second for measurement. Approaches can easily be flown below 40 kts indicated and GS. I'll explain the method below.
As a preface, this was an opportunistic performance check for interests sake, not a pre-planned exercise. So hold any questions on experiment design - this is only a practical check. My method was rounding out and holding off during the flare using a small amount of additional power, and using the GPS speed to confirm slow flight speed at steady-state pre-touchdown. I did landings on several different different vectors (the vectors are arranged in a triangle) to help identify the effect of any imperceptible breeze. All landings considered, it seems the practical results are +/-1 knot. Ambient conditions were about 200 ft AMSL, with temperature and pressures approximately at ISA for that altitude - which was convenient!
It’s hard to fly an aggressive STOL landing safely, with eyes inside the cabin monitoring speeds, while holding the aircraft at steady state pre-touchdown. Holding it a couple of feet off the ground, in other words. For that reason I didn't do an aggressive STOL landing, just an "average" STOL landing with a small margin for safety. So these results are not the best possible result, like you would expect in a STOL contest scenario. The plane can certainly land slower if pushed to the limit.
Note that our aircraft has extended hoerner wingtips fitted, not the common rounded wingtip.
So to summarise:
Approaches 38 kts
Rounding out / flaring at 37 kts
Touchdown somewhere just above 33 kts, without pushing it too hard.
Of course the safety caveat - each homebuilt aircraft is different, has different performance characteristics, and air conditions do vary. Please fly to the ambient conditions and your own aircraft's limits!
I think this is awesome performance for an honest 4-place aircraft.
Over the years, the 4-place has certainly allowed us to keep up with Super Cubs, in terms of landing on the shortest gravel bars etc. Given the high cruise speed and low-end STOL performance, it's hard to beat.
The best fun is had when very lightly loaded, with a cold high pressure morning, and a steady headwind. The plane can do some truly amazing things on those special days. For instance, a 30% climb angle with decent headwind is practically achievable from a standing start - measured over the ground, not through the air. Again, this is about practical or "useful" STOL performance, rather than a highly accurate measured result. Being able to land two full grown men and a decent load gear in a 60 metre (200 ft) space is a lot of fun, and challenging. Lately this has proven useful, on a couple of occasions.
Having full power applied is a large part of the take-off equation, so holding the aircraft at steady state to make observations isn't an option. It happens very fast in a IO-540 powered ship.
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