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Home✈️Aircraft🚁HelicopterHelicopter Main Discussion › "Home Machined" Blade Extensions
02-25-2010 04:54 PM  10 years ago
AirWolfRC

rrProfessor

42½ N, 83½ W

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It's just an optical delusion.

Are the lines really bent ?
Or are you just corss-eyed ?
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02-25-2010 05:07 PM  10 years ago
VooDooX

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San Francisco Bay Area CA, US (San Mateo)

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i concede ... have fun arguing i know im right no further need to make sure you are rightVelocity 50 "99.9999999999999% of an atom is empty space." also 01001000 01001001
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02-25-2010 05:22 PM  10 years ago
AirWolfRC

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42½ N, 83½ W

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VooDooX, you're right, don't give up !
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02-25-2010 05:23 PM  10 years ago
red_z06

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Dumont, NJ

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i concede ... have fun arguing i know im right no further need to make sure you are right
Except for few early posts, I don't think anyone is arguing that you are wrong.

The bit about the 1mile track vs 1.1mile (assuming same track width) track maybe easier to see than my method.
www.JustinJee.com
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02-25-2010 07:45 PM  10 years ago
steve69

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Berkshire, UK.

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Yes it will take off!
Steve.
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02-25-2010 07:46 PM  10 years ago
VooDooX

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San Francisco Bay Area CA, US (San Mateo)

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i get into trouble if i dont concede lol already have enough pinks 16 already had to edit my last post 3 times on concerns it wasnt PC enough it originally said you were all dumbf$#cKs lolVelocity 50 "99.9999999999999% of an atom is empty space." also 01001000 01001001
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02-25-2010 09:04 PM  10 years ago
broggyr

rrKey Veteran

Naugy, CT

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originally said you were all dumbf$#cKs
It's true. I am.

- Brian
irony [ay-ruh-nee', ay-er-nee'] adj.: Like goldy or bronzy, but made of iron
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02-26-2010 03:53 AM  10 years ago
HeliNerd

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Navarre, FL

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If anyone has ever looked at the CH-53E model heavy lift Helo, it uses 2 foot blade extensions. Exact same blade as the regular MH-53/CH-53D but with blade extensions for an increase in lift area. Works great! 70,000 lb takeoff weight.
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02-26-2010 03:05 PM  10 years ago
AirWolfRC

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42½ N, 83½ W

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Yep -- that's a lot of blade extension -- CH53E -- also more blades than a "D"

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02-26-2010 03:08 PM  10 years ago
GyroFreak

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Orlando Florida ...28N 81W

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Holy Crap, what a head button !!!!!!I think about the hereafter. I go somewhere to get something, then wonder what I'm here after ?
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02-26-2010 03:30 PM  10 years ago
red_z06

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Dumont, NJ

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I think only Green Giant can use that head button. www.JustinJee.com
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02-26-2010 03:45 PM  10 years ago
VooDooX

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San Francisco Bay Area CA, US (San Mateo)

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is it just me... or do those blades not look evenly spaced like there should be one behind his head thats not there..Velocity 50 "99.9999999999999% of an atom is empty space." also 01001000 01001001
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02-26-2010 04:14 PM  10 years ago
jphilli

rrKey Veteran

Atlanta, Ga.

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is it just me... or do those blades not look evenly spaced like there should be one behind his head thats not there..
I was thinking the same thing but I'll leave it to an optical illusion as it's a seven blade design.
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02-26-2010 05:05 PM  10 years ago
QuantumPSI

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Atlanta, GA

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Or they could be in the middle of unfolding......now where was I, dh/dt = BS-dx/dt
I will fly you forever... till earth do us part
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02-26-2010 05:24 PM  10 years ago
Dauste

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ES - UK

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Yep, they are just folding/unfolding them on the deck.
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02-26-2010 09:49 PM  10 years ago
MutantGarage

rrNovice

Texas, USA

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Got the calc for the blade pulling force on the feathering shaft?
How much of an increase in the outward force on the bearing is there with the extension?

Anyone ever test to failure a head with an instrumented load?
Build a test stand with a head and some sawed-off blades, fix one blade to the stand and put a hook on the lower blade and add weight until it fails. That's your static max tensile strength, probably should be 2X the calculated operating blade pulling force.

Ie, if you figure each blade is pulling with 600 lbs force at 2000RPM, the static test should hold to 1200lb (that's a lot of weights, you'll have to use hydraulics/leverage to reasonably get that much force.) Also need to think about where things are going to end up when it does fail.
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02-26-2010 10:15 PM  10 years ago
AirWolfRC

rrProfessor

42½ N, 83½ W

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That's your static max tensile strength, probably should be 2X the calculated operating blade pulling force.
? ? ?
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02-26-2010 10:28 PM  10 years ago
VooDooX

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San Francisco Bay Area CA, US (San Mateo)

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airwolf! you should get his techno babble.. your AREEE a professor are you not?! basically that says how much weight till the blade snaps and then how much weight is being put on the blade now and it the weight now greater then half the weight it can stand that's what i get outta it hahaVelocity 50 "99.9999999999999% of an atom is empty space." also 01001000 01001001
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02-26-2010 10:34 PM  10 years ago
AirWolfRC

rrProfessor

42½ N, 83½ W

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I don't know where he gets that 2X stuff. It's the same.

. . . and yes, I have claculated the tail blade forces when I was doing the tail blade chinese weight tests.
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02-27-2010 03:25 AM  10 years ago
red_z06

rrProfessor

Dumont, NJ

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I don't know where he gets that 2X stuff. It's the same.
He is referring to the design load. Using FS( factor of safety) of 2, if a normal load is 600lb (not verified), then he is saying the spindle failure point should be around 1200lb so it will safely handle 600lb load.

If the grip bolts use low grade steel, the shank would withstand shear load of 50-60% of Tensile load. Low grade bolt tensile is about 75,000psi.

Using 50%, shear stress will be identical to tensile of 75,000psi due to two shear locations (upper and lower grip joints). So, for practical purposes, you can say that shear strength of a grip bolt is equal to tensile strength of that bolt.

5mm smooth shoulder bolt should withstand 75,000psi or 37,500psi per shear location.

Stress = Force/Area Force = Stress x Area
Force Total = 2 x Area x Stress
= 2 x pi x R^2 x Stress
= 2 x pi x ((5mm/2)/25.4mm)^2 x 37,500psi
= 2,280lbs

25.4mm is the conversion from mm to inch

The shoulder bolts in shear are easier to calculate since there are no stress concentration points. For example, smooth 5mm rod will handle many folds more stress than 6mm threaded bolt with 5mm minimum diameter.
www.JustinJee.com
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