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Author Topic: An interesting read  (Read 4324 times)

bomber

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An interesting read
« on: August 23, 2015, 11:04:50 am »

http://www.av8n.com/how/

Holiday reading if anyone wishes to join me...... In reading not the holiday.
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"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

KW71

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Re: An interesting read
« Reply #1 on: August 23, 2015, 01:14:10 pm »

Looks really interesting!  Thanks, bomber!
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bomber

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Re: An interesting read
« Reply #2 on: August 23, 2015, 02:07:11 pm »

I'm hoping somewhere in his text to identify the solutions to the spin problem.
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"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

aWac9

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Re: An interesting read
« Reply #3 on: August 23, 2015, 02:24:55 pm »

very complete,,
,,, with your permission I'll take to my library ..
thank you
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bomber

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Re: An interesting read
« Reply #4 on: August 23, 2015, 02:26:35 pm »

It's not mine, so no permission needed from me..
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"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

bomber

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Re: An interesting read
« Reply #5 on: August 28, 2015, 03:01:28 pm »

Guys all those interested in flight modelling need to read this... it's blowing away a lot of my misconceptions and I'm only on chapter 8 !!

it's written for pilots, so if you're interested in sim flying it's a must read on it's own.. but what it's not written for is aerodynamic engineers and as such it's absolutely fantastic in that there are no massive equations to get your head around.

Simon

this is mind blowingly obvious yet jsbsim believes wrongly that p-factor is to blame....

Initial Takeoff Roll



There are quite a lot of myths surrounding P-factor. For some reason, P-factor gets blamed for the fact that typical aircraft require right rudder on initial takeoff roll. This is impossible for several reasons.
• Nearly everybody these days learns to fly in nose-wheel type aircraft, which means the propeller disk is vertical during the initial the takeoff roll. Since there is no angle between the relative wind and the propeller axis, P-factor obviously cannot occur.
•Now let’s suppose, just for sake of argument, that you are flying a taildragger, in which the propeller disk is actually non-vertical during the initial takeoff roll. Common experience is that the most right rudder is required at the very beginning of the takeoff, before much forward speed has been achieved. The FAA Airplane Flying Handbook (reference 16) says this is because P-factor is worst at low airspeeds. This is clearly nonsense, because real P-factor is proportional to airspeed. In the initial moments of the takeoff roll, there is no relative wind, so there can’t possibly be any P-factor. Of course, if you are taking off into a headwind, there could be a little bit of P-factor — but does that mean if you take off with a slight tailwind there will be a negative amount of P-factor, requiring left rudder? Don’t bet on it.

The real reason that you need right rudder on initial takeoff roll is because of the helical propwash, as discussed in section 8.4. P-factor exists in some circumstances, but it cannot possibly explain the behavior we observe during initial takeoff roll.
« Last Edit: August 28, 2015, 03:06:59 pm by bomber »
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"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell

M7

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Re: An interesting read
« Reply #6 on: August 29, 2015, 12:25:06 pm »

Me being a noob with flying sim stuff, i didnt get anything from your last post, but it got me seaching for what p-factor was. I didnt want to read through your link but checked on youtube and im still facinated at how quick you can learn with video compared to written though written is probably the only way to get deeper into concepts.

But now i can at least say that i understand your point and from the author explanation it makes a lot of sense.

Now i learned about other flying physics, one of them being  ground effect and i wonder if outerra has it?



« Last Edit: August 29, 2015, 03:02:47 pm by M7 »
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bomber

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Re: An interesting read
« Reply #7 on: August 29, 2015, 01:45:30 pm »

The cessna and glider has it,  however I'm thinking that having done some reading it needs modifying.

What also needs looking at is yaw caused by prop wash as at present I'm using default jsbsim p-factor
« Last Edit: August 29, 2015, 02:38:15 pm by bomber »
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"If anyone ever tells you anything about an aeroplane which is so bloody complicated you can't understand it, take it from me - it's all balls" - R J Mitchell