Propellers

Henning said:
He's not anybody, he's a mechanical engineer and this is mechanical engineer 101 stuff in my opinion, it's basically 150 year old technology, I would think a degreed mechanical engineer would have enough education that they would be able to work the system out by looking at it. There's only one way to do this mechanically really.
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Henning,

I think we got off on the wrong foot. I am sorry I came across as some "hayseed hick."

I have 44 years in the refrigeration industry and design and lay out refrigerant piping and mechanical systems for large grocery stores.

I worked on the Saturn rocket test stand with my dad, who designed the blast doors and cooling pipes for the rocket boosters. ( 1 1/2 million/gph)

My grandfather invented the "hot stick" for replacing fuses on power poles.

I am a decorated veteran.

I have an engineering degree, electronics technology degree, and 26 home study courses through correspondence schools, as well as an associate in business.

I am a published author. Published in trade journals and also write humor articles.

I married my wife, 40+ years ago, and raised her three children. Then adopted 4 more children, who had been classified as "non-redeemable" for society. She is a published author of 5 books.

My dad, played golf with Ben Hogan, and ate lunch with Werner vonBraun.

I served as President of Refrigeration Engineers Service Society, and was the first in my family to get a college degree.

I am sure I could fly an airplane with a CSP and follow the controls out without any difficulty.

However, I am 25 miles to the nearest airfield and work 115 miles in the opposite direction.

It is easier to read a book, follow the diagrams, and get a thorough understanding from my recliner than it is to drive 25 miles, beg someone to let me fly their CSP in hopes of figuring out exactly how it works.

In my opinion, which is worth little in your eyes, I would rather do it my way first.

BTW, I have started studying for my Commercial ticket and will take the written test sometime this fall.

Maybe, just maybe, we could tone down the rhetoric a little and I am sure your advice would be beneficial. Rather than look at my faults and shortcomings, I am sure I could learn something from you if I received helpful hints and instruction.

I forgot to mention that I taught myself computer programming, had AOL purchase one of my programs, and invented an electronic rock crusher. At 16, I rewired our radio so that I could send and receive radio signals and talk to airplanes at the nearby airport.

Thanks for letting me rant and I will try and make an effort to learn from your posts. Everyone on this site is very helpful and even at my age, I will take all the advice and instruction I can get.

Terry :)
 
alfadog said:
Let's go one step at a time. MP is a bit of misnomer, IMO, because in a non-turbo, there never is higher pressure in the intake manifold than atmospheric. So the MP is measuring atmospheric pressure when the engine is off and can be used as a rough altimeter even (1" per 1000' so would read 25" at 5000' pressure altitude). Once you start the engine, the engine acts as a vacuum pump against the throttle valve and generates partial vacuum in the manifold. If there were a perfect vacuum the MP would read 0" but there is not so it reads, what, 10" at idle? As you add power, you open the throttle and kill the vacuum more and more, causing the MP to rise. Under full open throttle, the MP would again approach the atmospheric pressure of 30" Hg.

So MP is an indication of how far open the throttle valve is and the load on the engine.
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That's why they call it MAP not MP, Manifold Absolute Pressure. There is no such thing as a perfect "0" pressure with in the atmosphere, so there are only minus or positive pressures.
 
Terry said:
Henning,

I think we got off on the wrong foot. I am sorry I came across as some "hayseed hick."
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I think it works both ways, the scary part to me was if a degreed engineer can forget this stuff which I know he learned, WTF is gonna happen to me? Glasses this year, what next? lol
 
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Tom-D said:
That's why they call it MAP not MP, Manifold Absolute Pressure. There is no such thing as a perfect "0" pressure with in the atmosphere, so there are only minus or positive pressures.
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Yep, but it's all the same in the end, it just makes all the math easier if you use an absolute "0" reference. 'Vacuum Pressure' (that term is like fingernails on a chalkboard to me) measuring makes comparing to 1ATM simpler for humans to work their minds around.
 
Henning said:
I think it works both ways, the scary part to me was if a degreed engineer can forget this stuff which I know he learned, WTF is gonna happen to me? Glasses this year, what next? lol
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Thanks for understanding.

Terry :)
 
OK, I must have missed this thread when it got started. You wanted a book on propellers. Look for "Aircraft Propellers and Controls" by Frank Delp. It's pricey, but you can buy it used on Amazon for a lot lest than list price. AOPA also has a little demo of a constant spped propeller in their "Engine and Propeller" Interactive Safety Course. Here's a link:
http://www.aopa.org/asf/online_courses/
 
Terry:

If you want to PM me, I'll give you my phone number and/or e-mail, and I will tell you more about propellers than you will ever want (or need) to know.
 
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