Prop question

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Comanche flyer

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i have a 1958 comanche with a hartzell prop, i just got the prop overhauled, today when doing my preflight i felt the prop move, and i was able to move the full pitch by hand, got on the plane start it up warm it up and cycle the prop, prop works great, flew to gls prop maintain pitch no events, went back to beaumont check prop after landing and wont move, then in 10 min i was able to move it again, talk to the guy at san antonio propeller ( he overhaul the prop) and he say this prop is not spring loaded so once i land and oil back off the hub i should be able to move it, i being looking many friends planes i never felt a prop that would move the full pitch each way, any wisdom from anyone, prop works perfectly tough every person i discuss this is saying they never felt a prop doing that :confused:



Prop is a hartzell HC-92ZK-8D serial 279L
 
Prop has either a spring or an N2 reservoir to push to flat pitch in case of loss of oil pressure. That is why the engine rpm winds up when kids do poorly-executed inverted maneuvers in airplanes without an inverted oil system. On some propellors air loads can balance other forces and it will function with a broken spring or low reservoir. I cannot say if yours is one of these but what you describe is not normal unless you are a body builder. The prop blades can be forced to a pitch but mortal men need wooden paddles to do it, not bare hands.
 
w_privett said:
Prop has either a spring or an N2 reservoir to push to flat pitch in case of loss of oil pressure. That is why the engine rpm winds up when kids do poorly-executed inverted maneuvers in airplanes without an inverted oil system. On some propellors air loads can balance other forces and it will function with a broken spring or low reservoir. I cannot say if yours is one of these but what you describe is not normal unless you are a body builder. The prop blades can be forced to a pitch but mortal men need wooden paddles to do it, not bare hands.
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grandson showing off again in your wife's C-120 ?
 
JHW said:
grandson showing off again in your wife's C-120 ?
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This time it was my yellow aztec, but yes. Again there was a young lady involved. He has been begging me for a turn in one of my harvards, I am thinking that can wait for another 20 years give or take. In the meantime I will keep their mag points in my desk.
 
Comanche flyer said:
i have a 1958 comanche with a hartzell prop, i just got the prop overhauled, today when doing my preflight i felt the prop move, and i was able to move the full pitch by hand, got on the plane start it up warm it up and cycle the prop, prop works great, flew to gls prop maintain pitch no events, went back to beaumont check prop after landing and wont move, then in 10 min i was able to move it again, talk to the guy at san antonio propeller ( he overhaul the prop) and he say this prop is not spring loaded so once i land and oil back off the hub i should be able to move it, i being looking many friends planes i never felt a prop that would move the full pitch each way, any wisdom from anyone, prop works perfectly tough every person i discuss this is saying they never felt a prop doing that :confused:



Prop is a hartzell HC-92ZK-8D serial 279L
Click to expand...

See this:
http://www.google.ca/url?sa=t&rct=j...mKfhwPa7ldNZwUkOeb32QrA&bvm=bv.61725948,d.cGU

It's a .pdf and takes a few seconds to load. Page 2-5 describes a similar propeller (HZ series) that Hartzell makes. It uses centrifugal twisting moment to reduce pitch and hydraulic pressure to increase it. There is a small spring that is supposed to drive the blades to low pitch if the prop stops in a higher pitch, since the twisting moment forces are only there while the prop is rotating. That spring might not be applicable to the propeller in question. I couldn't find a manual on the HC series but I bet it's out there somewhere.

I have seen and easily moved the blades on such a propeller.

Dan
 
His prop does not have the spring inside but it should have some friction to rotate blade pitch as you are turning against blade clamp pressure, piston o-ring friction and pitch change linkages. If prop has been greased there should be very little movement fore-aft at blade tips. If dry then 0.100". Ensure blade tracks within 1/8" of each other. End play max= 0.060".

I would not fly without ensuring overhaul was accomplished per Hartzell. If a blade departs, your engine can be left hanging down during the emergency landing or worse.
 
No spring/N2 in the old hartzell hydroselective props. There are counterweight blocks that pull the prop back to the fine pitch against the oil pushing it forward. You can twist the blades on the bladder props (with difficulty). If the blades are trying in the clamps you got problems, if you can see it turning the rest of the linkage, that's probably OK. There should be a barely presettable fore-aft play. Do not over grease these hubs. Note well the proper procedure. Just pumping grease into the zerk until it starts oozing is NOT The way.

Not only blade tracking but check the relative setting of the blade pitch. Mine were out by about ten degrees when I bought the plane. Sure ran smoother after I fixed that.
 
His particular model ending in -8D does not have counterweights. Just aerodynamic forces Oops, I meant centrifugal twisting moment...thanks Dan for catching that.
 
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The correct manual for your propeller is here:

http://hartzellprop.com//wp-content/uploads/2012/12/169-0000-R02-AW.pdf

You prop has neither a spring or counterweights. As mentioned earlier, the main force actiing on the propeller is centrifugal twisting moment acting on the blades when the prop is operating. This drives the propeller to low pitch (high RPM). Oil from the governor drives the blades to high pitch (lower RPM).

I think what you are seeing here is after shutdown the oil is draining out of the system and once the oil is gone, it's easy to move the prop, as you only have to overcome o-ring/seal resistance to move the prop.
 
Comanche flyer said:
i have a 1958 comanche with a hartzell prop, i just got the prop overhauled, today when doing my preflight i felt the prop move, and i was able to move the full pitch by hand, got on the plane start it up warm it up and cycle the prop, prop works great, flew to gls prop maintain pitch no events, went back to beaumont check prop after landing and wont move, then in 10 min i was able to move it again, talk to the guy at san antonio propeller ( he overhaul the prop) and he say this prop is not spring loaded so once i land and oil back off the hub i should be able to move it, i being looking many friends planes i never felt a prop that would move the full pitch each way, any wisdom from anyone, prop works perfectly tough every person i discuss this is saying they never felt a prop doing that :confused:



Prop is a hartzell HC-92ZK-8D serial 279L
Click to expand...

You have gotten good technical answers, but if you want piece of mind you can find a few hundred Comanche owners here: http://forums.delphiforums.com/comanches/start

and you can pose the question to the group.
 
Put on a 3-blade, get rid of the AD.

That's what I have on mine.
 
EdFred said:
Put on a 3-blade, get rid of the AD.

That's what I have on mine.
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Me too, but judging from the model number of the prop he's got, he's flying a 180.
 
Yes my plane is a 1958
180, the price of a 3 blade is not friendly I rather get the plane ready for 2020 if ever happen :yes:
 
KRyan said:
The correct manual for your propeller is here:

http://hartzellprop.com//wp-content/uploads/2012/12/169-0000-R02-AW.pdf

You prop has neither a spring or counterweights. As mentioned earlier, the main force actiing on the propeller is centrifugal twisting moment acting on the blades when the prop is operating. This drives the propeller to low pitch (high RPM). Oil from the governor drives the blades to high pitch (lower RPM).

I think what you are seeing here is after shutdown the oil is draining out of the system and once the oil is gone, it's easy to move the prop, as you only have to overcome o-ring/seal resistance to move the prop.
Click to expand...

Exactly what hartzell told me on the phone :yes:


Constant Speed, Non-counterweighted, Non-feathering Propellers
Propeller models HC-92( )F-8( ), and HC-92( )K-8( ) Refer to Figure 2-4.
Constant speed non-counterweighted, non-feathering propellers are typically used on single engine aircraft.
Propeller blade angle change is actuated by a hydraulic piston/cylinder combination mounted on the forward end of the propeller hub. The linear motion of the hydraulic piston is transmitted to each blade through a sliding rod and fork system, connected to a blade clamp that rotates with the blade. Each blade is retained on the propeller hub by a blade clamp and thrust bearing. The thrust bearing permits the blade to change angle with the blade under centrifugal load.
Propeller forces consisting of centrifugal and aerodynamic twisting moment of the blades in various combinations are constantly present while the propeller is operating. The summation of these forces causes the propeller to rotate to a lower angle. A variable hydraulic force (oil under pressure from the engine driven governor) toward a higher blade pitch opposes the summation of these forces. Oil is metered by the governor to oppose these constant forces and maintain a constant engine RPM.
A non-counterweighted propeller requires governor supplied oil to increase blade angle. If the oil supply is lost, the non- counterweighted propeller will go to low pitch, or high RPM.
The weight of each propeller blade when spinning, generates centrifugal force and a twisting force that attempts to rotate each blade to a lower blade angle.
Air flow around the blade generates lift and an aerodynamic twisting moment that will attempt to increase or decrease blade angle, depending on flight condition and blade design. This force is generally very small in relation to the other forces.
 
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Comanche flyer said:
i have a 1958 comanche with a hartzell prop, i just got the prop overhauled, today when doing my preflight i felt the prop move, and i was able to move the full pitch by hand, got on the plane start it up warm it up and cycle the prop, prop works great, flew to gls prop maintain pitch no events, went back to beaumont check prop after landing and wont move, then in 10 min i was able to move it again, talk to the guy at san antonio propeller ( he overhaul the prop) and he say this prop is not spring loaded so once i land and oil back off the hub i should be able to move it, i being looking many friends planes i never felt a prop that would move the full pitch each way, any wisdom from anyone, prop works perfectly tough every person i discuss this is saying they never felt a prop doing that :confused:



Prop is a hartzell HC-92ZK-8D serial 279L
Click to expand...
I have the same propeller on my ‘62 180 Comanche. That’s the way they are, just a characteristic of that model prop. Been flying mine 12 year’s and been thru 2 inspection’s and no issue’s. I see no reason to replace it.

Jay
 
Jay Sparks said:
I have the same propeller on my ‘62 180 Comanche. That’s the way they are, just a characteristic of that model prop. Been flying mine 12 year’s and been thru 2 inspection’s and no issue’s. I see no reason to replace it.

Jay
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You *did* get the notice that this thread was nearly 10 years old before posting, didn't you?
 
Rgbeard said:
You *did* get the notice that this thread was nearly 10 years old before posting, didn't you?
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While reading, I was trying to understand the “joke” on post #17 about 2020.

Then I noticed the posting date. Lol
 
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