Scrap Value

[markejackson02]

Two flights so far and all seems well.  No sign of leakage, no grease and no flying lock rings :-)

Course now the battery died.  Subject for another thread.

 

[jetdriven]

Did the prop shop cover the cost of repairs?

[bradp]

Without money there would be no magic machine to show off your magic skills.... ha ha ha

I stand by my observation that money is what makes an airplane fly. It simply can't happen without money. Even the Wright brothers would have never flown without money.

For a plane just throw the money in front of the prop (hopefully functional) and it will get sliced and diced. If you're even luckier the rpm will change so you can get a tear down out of it too. For our turbine friends don't worry it will count as FOD.

I guess for a boat you just throw the money overboard. A lot simpler.

I'm not sure in what scenario you toss the money into a burning hole in the ground.

:-p

 

 

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[carusoam]

Let's see...

It hasn't been a month since the engine was about to tear itself from the mounts and Grim the reaper was on speed dial.

That's the amount of time it takes to have a good battery drain itself.

I vote for a nice slow charge for the not quite old battery.  (Applies to Concordes, a two year old Gill may actually be dead)

PP thoughts only, not a mechanic.

Best regards,

-a-

[EricJ]

3 hours ago, bradp said:

I'm not sure in what scenario you toss the money into a burning hole in the ground.

Radio-controlled airplanes.  

[markejackson02]

10 hours ago, carusoam said:

Let's see...

It hasn't been a month since the engine was about to tear itself from the mounts and Grim the reaper was on speed dial.

That's the amount of time it takes to have a good battery drain itself.

I vote for a nice slow charge for the not quite old battery.  (Applies to Concordes, a two year old Gill may actually be dead)

PP thoughts only, not a mechanic.

Best regards,

-a-

The battery (Gill G-35) has been on a Battery Minder.  Great product.  Unfortunately it masked the charging problem because the plane started up just fine.  It wasn't until I flew it for an hour, put it away and came back two days later that it wouldn't start.  It was only producing 10V when I turned the key.

[Yetti]

did it go back on the charger?  If it was sitting then you have an alternator problem

[sleepingsquirrel]

http://www.dept.aoe.vt.edu/~lutze/AOE3104/thrustmodels.pdf

A 200 Horsepower engine drives a 6.5 ft diameter propeller. What would be an estimate of the thrust in the static condition? 200 hp x 550 ft lbs/sec hp = 110,000 ft lbs/sec The area of the propeller disc is A = D2 /4= 6.52 / 4 = 33.18 ft2 The estimated maximum static thrust is: We can estimate the actual static thrust is 90% of that or 1116 lbs.

I doubt any human can exert a force anywhere near 1116 lbs on the propeller hub by pulling on the prop.

Cessna 170, 172 &175
MT Propeller Performance Test Results
Flight Resource, LLC for STC # SA02245CH
Engine: Lycoming 0-360-A1A, 180HP @ 2700 rpm
Ambient conditions: 1000 MSL and 75F aircraft at #2550 lbs
Propellers Tested:
MT MTV-15-B/210-58. 83” 2-blade composite prop. (Constant speed)
MT MTV-15-B/205-58. 80” 2-blade composite prop. (Constant speed)
McCauley 1A200DFA 82/42. 82” 2-blade aluminum prop. (Fixed pitch)
Hartzell HC-C2YK-1A 74” 2-blade aluminum prop. (Constant Speed)
Hartzell HC-C2YK-1BF 80” 2-blade aluminum prop. (Constant Speed)

Static Thrust (2700 rpm):
MT 2-blade 210 cm 806 pounds
MT 2-blade 205 cm 790 pounds
McCauley 2-blade (2450 RPM) 750 pounds
Hartzell 2 blade 74” long 625 pounds
Hartzell 2 blade 80” long 737 pounds

 

Edited May 8, 2017 by sleepingsquirrel

[170driver]

http://www.dept.aoe.vt.edu/~lutze/AOE3104/thrustmodels.pdf
A 200 Horsepower engine drives a 6.5 ft diameter propeller. What would be an estimate of the thrust in the static condition? 200 hp x 550 ft lbs/sec hp = 110,000 ft lbs/sec The area of the propeller disc is A = D2 /4= 6.52 / 4 = 33.18 ft2 The estimated maximum static thrust is: We can estimate the actual static thrust is 90% of that or 1116 lbs.
I doubt any human can exert a force anywhere near 1116 lbs on the propeller hub by pulling on the prop.
Cessna 170, 172 &175
MT Propeller Performance Test Results
Flight Resource, LLC for STC # SA02245CH
Engine: Lycoming 0-360-A1A, 180HP @ 2700 rpm
Ambient conditions: 1000 MSL and 75F aircraft at #2550 lbs
Propellers Tested:
MT MTV-15-B/210-58. 83” 2-blade composite prop. (Constant speed)
MT MTV-15-B/205-58. 80” 2-blade composite prop. (Constant speed)
McCauley 1A200DFA 82/42. 82” 2-blade aluminum prop. (Fixed pitch)
Hartzell HC-C2YK-1A 74” 2-blade aluminum prop. (Constant Speed)
Hartzell HC-C2YK-1BF 80” 2-blade aluminum prop. (Constant Speed)

Static Thrust (2700 rpm):
MT 2-blade 210 cm 806 pounds
MT 2-blade 205 cm 790 pounds
McCauley 2-blade (2450 RPM) 750 pounds
Hartzell 2 blade 74” long 625 pounds
Hartzell 2 blade 80” long 737 pounds
 

Phew! Thanks for that. "Opinions" about measurable things like forces on a propeller drive me nuts. In my opinion my shoulder would dislocate long before I could exert enough force on a propeller blade to damage the hub.


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[markejackson02]

5 hours ago, Yetti said:

did it go back on the charger?  If it was sitting then you have an alternator problem

I let it sit for two days after flying without the charger on.  That's when it died.

[EricJ]

57 minutes ago, 170driver said:

Phew! Thanks for that. "Opinions" about measurable things like forces on a propeller drive me nuts. In my opinion my shoulder would dislocate long before I could exert enough force on a propeller blade to damage the hub.

 

FWIW, I did just notice this in an early M20J POH:

 

[mooniac15u]

On May 8, 2017 at 1:54 PM, 170driver said:

 

Phew! Thanks for that. "Opinions" about measurable things like forces on a propeller drive me nuts. In my opinion my shoulder would dislocate long before I could exert enough force on a propeller blade to damage the hub.


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Did you just tell us opinions on this drive you nuts and then offer your opinion? 

[170driver]

Did you just tell us opinions on this drive you nuts and then offer your opinion? 

Yes I did! My opinion concerned the amount of force required to dislocate my shoulder. This could be determined precisely by experiment, but I'm not willing to do that experiment. Forces experienced by propeller hubs in all corners of the flight envelope have been modelled, analyzed and measured many times over and the results are available to us. Opinions should be reserved for such topics as paint schemes, the merits of high wing vs low wing aircraft, and whether or not tailwheel training improves a pilot's moral character. In my opinion, anyway.



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