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Old 02-16-2006, 10:35 PM   #1
grebus
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Default Hartzell 90" prop

I've just acquired my first old prop, a Hartzell 707/80 which according to the great reference you provided is for the sexy Beech staggerwing or the unsexy bamboo bomber. Does the SN 32505 date this prop?
Does Hartzell or Sensenich answer questions about individual props like this? If a prop had canvas on the leading edge and tips, was this from the manufacturer or added later? This one has some holes on the LE and nails in the tips. but no remaining metal or canvas. I'd surely appreciate some insights.
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Old 02-17-2006, 01:02 AM   #2
Dave
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The canvas and brass tipping was added at the factory. On yours, it sounds like it was subsequently removed. Although Sensenich publishes a list of serial numbers corresponding to dates of manufacture, I'm not aware that Hartzell has a similar service.
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Old 02-17-2006, 11:03 AM   #3
MWP_Lamar
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According to Hartzell's employee historian, they do not have serial number information on their older wooden props available.

According to the experience of others, sometimes Sensenich will answer email concerning older wooden props and sometimes they don't. Hartzell won't.
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Old 02-21-2006, 09:46 PM   #4
grebus
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Thanks, Dave. Can you give me an idea why there is canvas on a propeller? It seems illogical.

And as to the Hartzell prop I inquired about, does ATC No 457 along
with the design number and other information constitute a military designation?
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Old 02-22-2006, 02:33 PM   #5
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The canvas presumably helps protect the tips from delaminating as well as from damage from stones, dirt, even water, etc. It was a very common practice in the early propellers, and has continued since, even with the addition of metal sheathing.

I believe all propellers built under military contract will have a separate designation, usually the contract year, followed by "K", followed by an entirely different number than the civilian drawing number. Lamar has listed these for Sensenich props (http://www.modernwoodenpropellers.co...h_military.htm), and I know Hartzell has some similar contract numbers as well. I think some military designation numbers appear on props manufactured by different manufacturers, presumably under some licence agreement.
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Old 03-11-2006, 12:02 AM   #6
grebus
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Default Hartzell 90" Prop

Thanks for the knowledge. Probably all that this propeller deserves.
But to go further for the sake of enlightenment, this propeller has, in
addition to the Hartzell, Piqua, serial number, HP, RPM, and design number 707/80 (90), "ATC No 457".

So I referred to the FAA site's approved type certificate documentation.
It shows that ATC 457 is for Stinson Jr. R, 4PCLM, with Lycoming R680
215 HP. It's approved for aircraft manufactured prior to 2/1/34, which
dates it within the period of the Beech Staggerwing, for which the
prop is designed.

So is it reasonable to speculate that this prop was special for that Stinson application, or am I trying to relate two different things?
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Old 03-11-2006, 08:00 AM   #7
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I think you are relating two different things. The ATC 457 is the propeller type certificate number for that model, but there may be an aircraft type certificate with the same number. I'm not aware of any FAA site (or other source) that lists propeller type certificates and what aircraft they apply to.

Do you have the link to the FAA site you used? I actually spoke with the FAA last week about this, and they said that for older props even they have to consult the manufacturer most of the time.
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Old 03-13-2006, 09:11 PM   #8
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Default Hartzell 90" Prop

Dave, I think you are right that the series of ATC numbers for propellers is different from the ATC's for aircraft, and that the numbers may be duplicated. The FAA site I visited was http://www.airweb.faa.gov/licenses_c.../aircraft_type certificates.
If I didn't get that just right, you may have to go in through the menus.

There was a section for propellers, that didn't contain any data, and
the ATC No 457 I had viewed was under aircraft.

Upon actually reading the full specs on the ATC, I see that it includes an adjustable metal propeller. So that's fairly conclusive.

But if they created the propeller section on their site, they must have some information stuffed in boxes or on microfiche. Is it worth sending an
inquiry?
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Old 03-15-2006, 05:05 PM   #9
MWP_Lamar
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The FAA does have some info on wooden props. I have some of their listings. Unfortunately, they don't list any aircraft usage but they do list hub dimensions which may prove useful in the future for determining engine applicability.
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Old 01-25-2009, 12:39 AM   #10
lselan
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Default Hartzell 90" Prop

Having recently purchased the Number 24 issue of Warbird Digest which contains an article on the Cessna T-50 Bobcat ("unsexy Bamboo Bomber"), I decided to revisit the propeller in my study. Given to me in 1976, while living in Wichita, Kansas, this is also a Hartzell 707\80(90), ATC. 457. The serial number is 32430 for a 225 HP engine. While there is some minor flaking of the varnish, it is in excellent shape with the brass leading edges in good condition.

When I received it, I contacted Hartzell, who as pointed out, even then did not have information on serial numbers that old. They referred me to the Air Force Museum in Dayton, Ohio. The response I received at the time, was that this was probably from the early models or prototypes of the T-50 Bobcat. Apparently while the prototypes used wooden props, the production models had metal props. As I recall they said there was a limited number of these produced, but unless there are breaks in the serial numbers, there are at least 65.

Verification/correction appreciated.
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