quick question -

Bertie the Bunyip wrote in
:

Marty Shapiro wrote in
:

Bertie the Bunyip wrote in
:

Yeahm but you have a big engine one, don;t you?

Been years since I've flown one, but the slats should alter the
chord line and give a high deck angle with no flaps out.

Yes, I have the 235. I've never flown the smaller ones.

The deck angle is even higher with the flaps out. When I want to pop
it off the runway, I use 1/2 flaps (at this setting, they are pretty
much only about 15 degrees down, but at maximum extension)and pitch
for Vx. Trim for Vx and then simply raising the flaps will lower the
nose slightly and put me right on Vy.

The slats, as you know, are automatic, and will pretty much stay out
in a climb until you lower the nose to about 85-90 MPH indicated. The
slats are in for a cruise climb (106 MPH).


hmmm, strange that the angle would be higher with flaps out, The mean
chord line should change and require a lower deck angle for a given
airspeed.


Bertie


That's a very good point, Bertie.

When doing power on stalls, it works exactly as one would expect. I have a
significantly higher angle of attack to get to stall buffet with the flaps
in than with them out. In fact, with flaps in, you need to get up to
nearly 30 degrees nose high just to start getting stall buffet. I remember
the first time I did this I thought I was going to roll backwards out of my
seat. But in this case I'm comparing no flaps to full flaps, which is
almost 45 degrees.

Remember that the Rallye also has Fowler flaps. In the maximum effort take
off, 1/2 flaps basically only lowers them 15 degrees while reaching maximum
rearward extension. I'm wondering if in this case the change in speed from
75 MPH (Vx) to 81 MPH (Vy) offets the effect of the 15 degree downward to a
greater extent. Anything less than 1/2 flaps and all you have done is
extend them rearward with no downward angle.

--
Marty Shapiro
Silicon Rallye Inc.

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