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## Some questions

• sydpilot
• Topic Author

### sydpilot created the topic: Some questions

Hi,

On page 3.7 there is mention of 'approximate behaviours of the lift and drag coefficients and lift/drag ratio for the Cessna 152 wing are shown on page 3.8' There is no chart etc. on page 3.8. Page 3.8 talks about the Aerodynamic Centre.

On page 7.7 of the book the statement 'Minimum drag always occurs at a higher speed than minimum power' has me confused.
Is this referring to the minimum drag on the total drag curve as compared to the minimum power on the power required curve?

Thanks.

• Posts: 2311

### bobtait replied the topic: Some questions

Page 3.8. This page was modified to include the section on Aerodynamic Center and the original figure was removed in error. I have replaced it in the current print of the book. Thanks for your feed-back. Here is the new page.

#### File Attachment:

File Name: SECTION3.8...13AM.pdf
File Size:160 KB

Page 7.7. Figure 7.10a shows the power curve where the very bottom of the curve locates minimum power (maximum endurance). However the tangent to the power curve locates minimum drag (maximum range in no wind) on the same power curve. Since the tangent to the power curve must always touch the curve further to the right than the minimum power point, the speed for maximum range will always be higher than maximum endurance. This will be true for all piston engined aeroplanes.

• sydpilot
• Topic Author

### sydpilot replied the topic: Some questions

Thanks Bob

Referring to the tanker and the fighter question on page 7.2, my reasoning is the tanker would need to fly at a slightly lower AOA and reduce power so speed does not increase and the fighter would need to raise AOA for lift to match weight and increase power so speed does not decrease. Is this correct?

• Posts: 2311

### bobtait replied the topic: Some questions

That's exactly correct. Now you've got it!