quick question -

Marty Shapiro wrote in
:

Bertie the Bunyip wrote in
:

Marty Shapiro wrote in
:

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.


Yeah, could be. We have a similar setup on most jets where they
travle
backwards for the first couple of settings. The slats come out at the
same time so the airplane tends to sit a couple of degrees more deck
angle than it does clean.



Don't you have control of the slats on the jets you fly? On the
Rallye
they are automatic based on angle of attack.


We do, but on most airplanes they come out when you select flaps.
Ususally, there are two slat positions, depending on the type of slat.
The first stage of slats comes out when you select the first stage of
flap and the second stage of slats comes out when you select the final
stages.
On airbusses, though, at least most of them, the frist selection
position selects slats only,and this is often the position you take off
in. No flaps and slats at 15 deg. Other guys not familiar with this wil
shout at you that your flaps are up as you taxi onto the runway if they
happen to be behind you.


Bertie