Angle of incidence

[quote=Mike C;815406]On May 27, 11:21*pm, Roel Baardman wrote:
After speaking with an instructor about my Pilatus B4 landings, he argued that
the angle of incidence on this glider has a great influence on the landing
characteristics.
I looked it up, and it was only 1.5 degrees. With the tailplane oriented at -3
degrees.

However, I cannot figure out what other gliders have as the angle of
incidence. I have 6 degrees in my head somehow, but I'm not sure where I get
this from. Searching on Google does not give me figures, only stories about
changing it (from Ls6 to Ls8 for example).

I'm therefor wondering: can you tell me the angle of incidence on your glider
if you know it? And how does it effect take-off and landing characteristics?
For example: some people in my club argue that the Discus2 take-off
characteristics are also to be blamed on its angle of incidence.

regards,

Roel

I would be interested in exactly what problems you are encountering on landing. I am interested in the Pilatus B-4 for its aerobatic capabilities. While it would not necessarily be a good cross country airplane, cross country does not interest me all that much.

Having read the B-4 manual I was surprised to see that it did not discuss the landing process to any degree. I fly a SGS 1-34 which recommends a high energy landing and the manual specifically recommends against landings resulting in a tail first or tail strike landing. Somewhat nonintuitive for someone trained in powered taildraggers recommending a full stall, three point type landing in otherwise non windy conditions. Essentially the 1-34 is flown onto the ground and then flown to a stop as mentioned in the manual. I had the good fortune to talk to several pilots with extensive experience in the 1-34 prior to flying it. I would think this would always be advisable as we transition into other aircraft.

Walt

Hi Walt,

Although my opening post starts with the B4 and landing, this does not mean it's
tough to land. Not at all.
I have a tendency to fly fast on final, and the ground effect of the B4 makes it
float when I do that.

In my experience it is a great glider to fly. I can compare it with an ASK-23 and
SZD Junior, both being gliders which are flown by pilots with some solo starts. In
fact, the B4 has been used for this purpose in The Netherlands in the past. The
glider is generally responsive and very friendly.

Pitch is somewhat sensitive, but nothing you can't get used to. The same applies
for rudder control. On my first flights I tended to put too much rudder in during
thermaling.

In terms of aerobatics I think the glider is a nice follow-up for the ASK-21 (on
which I learned to fly aerobatics). The pitch-sensitivity requires more precise
inputs during rolls. Also since the rudder is so effective, you can actually stall
the rudder when flying knife-edge at 3/4 of the roll. After some practice I could
do very nice rolls without having to pitch up 20 degrees.

Stall-turns are not hard, especially if you side-slip a little on the vertical
line up.

It warns before you spin (I can hear the airflow get turbulent over my wings, and
there's a *shoop* when it drops), the spin rotates quickly but can be stopped in
1/4 turn with rudder and then forward-stick. The glider then swiftly drops to 90
degrees down. Pretty perfect for competitions I would say.

Tailslides have a tendency to drop canopy-down/wheel-up (due to the wing-profile I
was told), so you should keep those a little positive if you want to drop
canopy-up/wheel-down.

I have tried inverted spinning, but am not sure how stalled the glider was during
this maneuver. It can perform the figure though.

I haven't tried snap-rolls, since I hear this will make the rivets in the tail pop
and give the tail play.

I have some videos with flights from start (tow) until landing. Drop me an e-mail
if you're interested.

Roel