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Skysurfer7

SP1: Vref+5 power flaps30 wrong?

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After SP1 i did following observations regarding flaps 30,40 (app on ILS) pitch & power on 800WL:GW 58.3, flaps 30, Vref+5, pitch 2.5 deg, power needed 43% N1GW 58.3, flaps 40, Vref+5, pitch 0.5 deg, power needed 63% N120% more power between flaps 30 vs 40, & pitch differers of 2 deg seems way off!


Kind regards
R.G

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It's worth noting that there is no lift whatsoever with flaps 40 !Just drag !!!!Fred.


Frederic Steiner.

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20% more power between flaps 30 vs 40, & pitch differers of 2 deg seems way off!
Based on what?

Mike Avallone

9900k@5.0,Corsair H115i cooler,ASUS 2080TI,GSkill 32GB pc3600 ram, 2 WD black NVME ssd drives, ASUS maximus hero MB

 

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63% - 43% N1 is not 20% less power, it is 20% slower N1 stage RPM. Turbine engines don't have a linear power curve like that. The N2 stage gives more of an idea how hard the thing is really working , however 65% on the ground is almost no actual thrust to speak of to move the plane. thats why you never saw turbines in cars since they have a power band that uses a lot of fuel just to run.EB Wallace

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Based on what?
EdubF-Sorry I should have wrote 20% more N1.Based on......Pitch & Power Settings on Final Approach as per Mr Boeing: Use 5deg nose up for initial flap settings. Use 2.5deg nose up for flap 30. For flap 30, start with 55% N1, then adjust as required.Allso from PPrune:"I got the pitch/power settings into my head i.e. Flap 5 level flight around 63% N1 and +7 nose up, then Flap 30 Gear down around 55-56% N1 and +2-3 nose up. I realise these are pretty ball park, but they worked well on the day."At 2500' agl platform level flght.""G/S: There are different techniques to achieve landing configuration at G/S capture. FCTM recommends Gear Down F15 at G/S alive. This will give N1 65%and about 7 degrees. Stop the balloon as flaps extend. Now it depends if F30or F40.F30: At 1 dot call F30 and set 53-55% and keep level. The speed should decay to Vfly (Vref + 5) as G/S is captured. Small N1% adjustments should be made to match the G/S capture rate to the speed decay. This is the same technique employed in SE ILS's. At G/S capture set 2 degrees and trim the elevator.F40: 1.5 dot F25 leave N1% at 64% at 1/2 dot select F40. The power setting at F15 is the same as F40 on finals. Thus there are no or very little power changes during the configuration changes and thus a/c control is easier."

Kind regards
R.G

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