Bearhawk STOL mods

[Westward_Flyer]

I'm eager for some news as well, this is one of the coolest BH mods I've ever seen.

[500AGL]

Just a bump as it looks like spring.

[Battson]

Some have been asking for an update.

The update is, heavy snow continues to prevent the aircraft from test flying. Expect more in spring

[Shopperly]

Happy New Year to all! I’m hoping for an update on the testing and would really like to see some video. Is there anything more that you can share?

[Gerd Mannsperger]

Great to see the flap Mods work as well as I would have expected.

The first thing I would do though is to instal VG's on the leading edge wing and on the tail surfaces as well as gap seals to maintain controllability at the slower speed.

One of the most important and usually overlooked benefits of VG's is how they help to maintain control at the slower speeds not just the reduction in stall speed.

One of the negative side effects of lowered stall speeds usually is reduced control at that slower speed, only VG's enhance control while reducing stall speed.

We had the same issues with Robertson stol equipped 180and 185s and the addition of VG's made the aircraft very controllable at the slower stall speed.

[svyolo]

Hopefully it turns out good. Do you happened to know if he has VG's, profiled tail, or gap seals on the elevator already?

[Battson]

One of the primary advantages of fowler or slotted flaps compared to other varieties of flap, they generate extra lift behind the CoP and lower the deck angle, creating increased visibility over the nose.

[zkelley2]

That's what flaps do. Lower the critical AoA.

[svyolo]

I don't think there is a carefully worded definition on Fowler flaps. "True" ones I guess have sliding tracks, and translate aft as well as rotate down. Very complicated and heavy, and usually have external tracks, but not always.

Jon;
Your description makes it sound like it stalls at a much lower AOA. Does that seem to be the case?

[Battson]

I tend to agree with your original conclusion though. I don't think it's a true fowler action. I have always thought it more of a sales pitch than a technically correct title.

Whatever you call them, it seems that it works.

[zkelley2]

Is this the angle valve 300hp bearhawk in utah?
That's a porker for sure at 1630.

[whee]

Thanks Battson. I couldn’t tell that they move aft in the videos I’ve seen so I always wondered.

[Battson]

Great results. The deck angle decrease is a welcome improvment.

Question: I often see these flaps refered to as Fowler flaps but I don’t see any aft movemt of the flap which is what defines a fowler. Are these not just double slotted flaps?

There is some aft movement, chord length increases by several inches, so technically they are semi-fowler, like a Cessna flap. It's an advertising thing I guess.
I have laid this out before over at BCP, and it was argued out by the panel. Same conclusion was reached.

[whee]

Great results. The deck angle decrease is a welcome improvment.

Question: I often see these flaps refered to as Fowler flaps but I don’t see any aft movemt of the flap which is what defines a fowler. Are these not just double slotted flaps?

[Battson]

I have gone through the details more carefully and revised the approach speed reduction from 4 to 6 knots less.

The stall attitude appears to be about the 3 point attitude, or slightly tail low - same as a Maule with slotted flaps.

The plane is question is about 1,630 lbs empty weight. Initial flight tests were done with 20 US gal of fuel.

The results I have shared are quite literally from the first three approaches and landings. They are subject to change as test flying continues.

The pilot remarks that while it was possible to approach in the mid thirties [knots], it was a sporty regime and was accompanied by a loss of elevator control and reduced visibility. High thirties was rock solid with good visibility.