The International Cessna^® 170 Association

A few of us who read the type certificate data sheet (TCDS) in our spare time and have an interest in the unusual have come to realize that a C-145-2H engine is required by the TCDS in order to use a Koppers
Aeromatic propeller on our 170s.

Those that know the C-145-2H know that the H indicates provisions for a hydraulically controlled propeller. We also know that the Koppers Aeromatic does not require such a control.

So it is odd that the C-145-2H is required for use of the prop. In fact a few of the association members, who shall remain nameless to protect the guilty, have admitted to running the Aeromatic on a plain jane C-145-2D or 0-300-A engine.

So the question arises. Was this a typo or incorrect information on the TCDS? It would not be the first time a mistake was found here.

So I would like everyone with a 170A or B to look at their aircraft records and see if it was delivered with a Koppers Aeromatic propeller item 1(c) on the TCDS and if so look to see what engine was installed.

Reply here or contact me privately with your engine model that was installed at the factory which would be either a C-145-2, C-145-2D or C-145-2H. If you have a late '55 or '56 170B model there is a possibility you might have had an 0-300-B installed from the factory and we are really interested in that.

Thanks

I did some investigating of the Koppers propeller after reading about it in another post about engine conversions. Below is an excerpt from the Koppers T.C.D.S. that eludes to some sort of hydraulic pitch control used by the F200-H propeller that the 170 type certificate specifies. Note 1 says that the -H in the model numbers specifies pitch control (if used). Note 3 describes the pitch control installation/operation.

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NOTES

NOTE 1. Hub Model Designation.

|------------ Basic model designation
|
F 2 OO - H
| | | |---- Pitch control (if used)
| | |
| | |-------- Aeromatic blade shank size
| |
| |----------- Number of blades
|
|------------- Flange mountings

NOTE 2. Blade Model Designation.

|---------- Basic model designation
|
P OO - 78 A L
| | | | |
| | | | |- Left hand version
| | | |
| | | |--- New design version differing from basic model
| | | physically and/or aerodynamically
| | |
| | |----- Propeller diameter in inches
| |
| |---------- Aeromatic blade shank size
|
|------------- If used, denotes the plastic covering.


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NOTE 3. Pitch Control. The model F200 is automatic in operation, and
requires no controls. The Model F200-H
incorporates a manual-hydraulic pitch control
which provides improved performance at altitude.
(Weight-Hydraulic cylinder -1-3/4 lbs. Control
value, transfer block, control cable and oil
lines - 6 lbs. approximately - dependent on
installation.)

This may be why the -2H engine is required.

Good catch Mark. I do note that it says (if used) Wonder what that means?

I've seen a few Aeromatics used on other airplanes and never saw a control for them as they where automatic.

Well lets see if we get anyone who's plane had the Aeromatic when delivered but didn't have the 2H engine.

Just found something interesting. The Meyers 145 which uses a C-145-2 is approved for the exact same Koppers Aeromatic prop as our 170s and a -2H engine is NOT required. Only a dampened crank version.

From TCDS 3A1 for the MAC 145

5. Propeller - Koppers Aeromatic F200H/00-74E Parts list assembly No. 4356H-1 34 lbs. (-61)
(Includes Altitude Control 4427) 6 lbs. (-46)
Adjustment and operation must be accomplished in accordance with
Koppers "Adjustment Instructions and Operating Limitations No. 45"
Low pitch setting 13° at 24 in. sta.
Static rpm at maximum permissible throttle setting: Not over 2675, not under 2575.
No additional tolerance permitted.
Diameter: Not over 74 in., not under 72.5 in.
(Eligible on Model MAC-145 only with Continental C-145 engine dampered crankshaft
denoted by suffix letter "D" after engine serial number).
Hampton propeller spinner Model 1-B optional.

So it is entirely possible our TCDS is wrong. Hmmmm.

Now THAT does sound mighty interesting! Good catch!

Bruce,

I'd be a bit surprised if the 170 TCDS is wrong. Frequently it's the engine/mount/airframe combination that affects whether an engine/propeller combination may be used. For example, the Curtiss-Reed 55501 propeller is approved for use with the W670-6A on a Waco UPF-7, but the same propeller is not approved for use with that engine on a Stearman.

How about this? The Swift GC-1B has the C-125-1 & -2 /Aeromatic prop combination on the TCDS. I know, it's a C-125, not a C-145. However, there is also an STC for the removal of the C-125 and the installation of the C-145 and Aeromatic prop.
http://rgl.faa.gov/Regulatory_and_Guida ... enDocument

The content of the STC is not available on the FAA website so someone would have to contact the Atlanta office for a copy.

Just to add a little intrigue, here's what is listed on the Swift website regarding this STC:

http://www.napanet.net/~arbeau/swift/stc.htm#engines

Cont C-145, O-300-A or -B w/Aeromatic or McCauley prop: For Globe GC-1B series. STC#: SA4-145
Description: Cont C-145-2, O-300-A or -B engine & Universal F200/0073-E, F200-H/0073-E, or McCauley 1A170DM/7361 propeller. M.E. Bodell, 23804 Pennsylvania Ave, Torrance, CA 90501


Obviously, this cannot be taken as gospel and we'd need to see the STC, but it certainly looks like something worth pursuing.

Bob

What is at contention here is whether the hydraulic prop control is used for the prop. The 2H has it and is required on the 170 TCDS. The -2 does not have it and the -2 is all that is required on the Meyers for the EXACT Koppers Aeromatic propellor model hub and blades.

The Meyers TCDS does require a dampened crank which would be a -2D. The -2H also has a dampened crank. The thinking being the H is a typo that should have been D.

There have been more than a few long time 170 people who have run the Aeromatic prop and claim to have done it with a -2 engine.

The purpose of this search is to try to establish whether CESSNA followed what is currently in the TCDS. I would like to find as many records of the Aeromatic from the factory and we will see what engine was installed an determine what was used.

Doug

I looked at the Swift TCDS and the key there is the model of Aeromatic prop is not the same. It calles for the F200 while the 170 TCDS calles for the F200-H

Interesting what the Swift people say about the STC which is another matter listing all the engine models and both models of Aeromatics.

I wonder what the difference is between the F200 and the F200-H? Hydraulically controlled? Is that the reason for the C-145-2H requirement?

I went to Kent Tarver's website ( http://www.aeromatic.com ) and while those models are listed, there is no information listed to provide a distinction between the two.

Doug I haven't looked at the TCDS for the prop but based on what is posted from it above it would seem the -H has some kind of hydraulic control or override for high altitude. See the note 3. Of course the indication from the same source it doesn't have to be used.

NOTE 3. Pitch Control. The model F200 is automatic in operation, and requires no
controls. The Model F200-H incorporates a manual-hydraulic
pitch control which provides improved performance at altitude.
(Weight - Hydraulic cylinder - 1-3/4 lbs. Control valve,
transfer block, control cable and oil lines - 6 lbs.
approximately - dependent on installation.)

This note 3 also indicates that the hydraulic control is it's own device independent of any the engine might have which lends itself to the theory the -2H is not required only a dampened crank which would be the -2D.

N9149A wrote:NOTE 3. Pitch Control. The model F200 is automatic in operation, and requires no
controls. The Model F200-H incorporates a manual-hydraulic
pitch control which provides improved performance at altitude.
(Weight - Hydraulic cylinder - 1-3/4 lbs. Control valve,
transfer block, control cable and oil lines - 6 lbs.
approximately - dependent on installation.)

This note 3 also indicates that the hydraulic control is it's own device independent of any the engine might have which lends itself to the theory the -2H is not required only a dampened crank which would be the -2D.

The control might be independent, but what is it's oil source? If you have a manual control and oil lines then it sounds to me like the requirement of the -2H engine makes sense. Where else would you have a hydraulic source to control the prop?

It looks like Cessna went ahead with the hydraulic version on the TCDS and left the "regular" Aeromatic off on purpose. Perhaps they felt the hydraulic version offered better performance and didn't want to waste time/money on the other? Or thought they could make more money on the hydraulic version? Wouldn't be the first time a sales group put the most expensive option on the list and left out a cheaper option that would probably meet 80-90% of most customers performance needs.

Doug I'm guessing the hydraulic cylinder would have it's own oil resevior like the other two we have n our plan we call master cylinders.

On the -2H oil pressure is feed to the prop through the center of the crankshaft. The control valve is inside the engine. There is no oil lines or extra hydraulic cylinder involved.

The fact that Note 3 indicates there is a hydraulic cylinder, control valve and oil lines involved indicates to me it is independent of any engine accessories.

Again hopefully people will look at their records and we can see what was delivered. I'm sure a few of us will be keeping our eye out for more info as we see these props which isn't very often.

Ok... now I get it

It would be nice if we could get some info from Cessna on what actually rolled out the door regarding the C-145-2H & the Aeromatic.