Polars

Study the polar for your ship. Know your expected sink every 10 kts (60 to 90)

McCready Settings

Computer knows the lift - set the McCready (Mc C) between 0 and 3

0 Mc C will command best L/D
> Mc C 1 and it commands higher speeds
You arrive sooner/ but lower

Computer knows the wind

Fly Faster in a headwind
20 kts head, add 10Kts
(TAS) ( < 5kts at 10,000)

Fly Best L/D in a tailwind

Change Mc C
Recognize your true average rate of climb
Use a clock – get a feel for ‘the truth’

Do you expect a better rate on next climb?
If so set McR to about 25% of current rate
( assuming you plan to arrive at next thermal ok)

Flaps?

Flaps on your ship? What speed to fly?
Just like polar curves
Know the speed range of each flap setting!

ASH26
If Weight = 980 lbs, then Flaps = 2 ( 65 to 90kts)

Optimum flap speeds are critical

Practical experience has proven this to be a major truth
(formation using both DG800 and ASH26 against the ASW20’s)

Sink vs. Lift

In calm air, sink and lift

Calm air: (indicated vario = -150 fpm +/-)

Speed: L/D plus 5 to 15 kts (65 to 80 kts)
Depends on “safe” altitude… distance to landout, to next lift

Sinking air: (indicated vario = -200 fpm +)

- between thermals
-200-300 fpm Speed: 75-80 kts
- back of wave or ridge
-300-500 fpm Speed: 85-90 kts
-1000 or more Speed: 95-100

Lift: (indicated vario = 0 or better)

- convergence +100 fpm Speed: 58-65 kts

- cloud street +100 +500 Speed: as req’d
(at least 500-1000 below cloud)

 

See graphics:

1- polar-asw24.jpg

2 - polar-ash26.jpg with sink vs speed

3 - polar-dg800b.jpg

4 - L-D-asw24-vs-dg800.png

5 - flap-v-ash26.png

6 - polar-ash27.jpg

7 - polar-ash26E.jpg

 

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