30) The climb gradient of an aircraft after take-off is 6% in
standard atmosphere, no wind, at 0 ft pressure altitude.
Using the following corrections:
"± 0,2 % / 1 000 ft field elevation"
"± 0,1 % / °C from standard temperature"
" - 1 % with wing anti-ice"
" - 0,5% with engine anti-ice"
The climb gradient after take-off from an airport situated
at 1 000 ft, 17° C; QNH 1013,25 hPa, with wing and
engine anti-ice operating for a functional check is :
A) 3,9 % (Mark scheme answer)
B) 4,3 %
C) 4,7 %
D) 4,9 %
->My workings: 6%-0.2%-1%-0.5%=4.3% (no temperature correction as at SL it's standard)
But you do need temperature correction, at 1000ft temp in I.S.A. would be standard 15 - 2 = 13. Now it is 4 degrees above that.
68) How does the thrust of fixed propeller vary during takeoff
run ? The thrust
A) increases slightly while the aeroplane speed builds up.
B) varies with mass changes only.
C) has no change during take-off and climb.
D) decreases slightly while the aeroplane speed builds up. (Mark scheme answer)
->Okay I know that fact but I don't understand why.
I also don't understand the answer, it says in the powerplants book that a fixed pitch prop is most efficient at cruising speeds. So to me it would seem that thrust would increase to start with.