The International Cessna 170 Association

Thanks guys. That is some good information. I'm going to have to save this for future reference.

I hesitate to keep showing my ignorance but....

How are you guys getting approval for the 80 inch prop on a land plane? Everything I see about the 80 inch prop says "seaplane". I haven't seen a copy of the Kenmore STC. Does it have a provision for land planes? Is there another STC that approves it? Or is this being done on a field approvals? Don't ask, don't tell?

Thanks for all the help. I've always been in the pilot end of this business. I've learned a lot about the mechanic end lately.

I've got about a week to find an overhauled prop, which is proving more difficult that I had expected. I do have a lead on a used 7654 "as removed" and the price is right. I might take a chance and go with that or just bite the bullet and order a new one.

K

Try Air Salvage of Dallas and talk to "Lueke" (Lucky) . He had a EM7653 on his wall last time I looked and it was in excellent condition for about $1200 I think.

The certification (CAR) for prop-length requires 7-9" of tip-to-ground clearance in the takeoff condition (tailwheel - up) with the landing gear deflected for 1.5 G's. If you have taller gear legs (i.e. 180 gear) it will provide some additional perhaps.

The Kenmore Air Harbor STC (SA111NW) covers 170A and 170B land and sea planes with O-300A and O-300B engines. Limitations are 80" maximum and 78.4" minimum diameters, prop IA175DM, Spinner Cessna Drawing # 0550162

G'day All,

I have been quite busy here with a record winter spray season leading into a big summer season. What a nice relief from the drought we have had. I went from not turning a blade in May, 25hrs ferry time in June (thats a whole other storey), had most of July off recovering from the ferry job and had a baby boy. Then in August things started to pick up.... I have logged over 900hrs since the start of August. (A 10hr day in the log book typically involves about 15hrs in the cockpit!) Although I have not contributed to the forum for a while I have one of these fancy new phones with internet and have been following the forum daily.

Back to the subject - I just thought I'd add my experience...

I just swapped the DM7653 prop on HVS for an MDM7653 (from what I've read this would be the same profile as the EM7653). The MDM came with the plane when I bought it and has only 350hrs since new on it. I was curious as to why anyone would change to a less efficient model.

I ran a trial with both props. I ran each trial 3 times to get an average result. To be fair it was hot and bumpy and not ideal for repeating each criteria but this was the only time I had available for this. This is an average of what I found...

DM7653...
OAT 31'C
P Alt - 700'
T/O RPM - 2270
T/O DIST - 248m
DIST TO TREE TOP (APPROX 40FT) - 638m
CLIMB RPM @76KTS - 2420
R.O.C @76KTS - 400FPM
CRUISE SPD 2500RPM 1700FT - 100KTS


MDM7653
OAT 31'C
P ALT - 700
T/O RPM - 2320
T/O DIST - 226m
DIST TO TREE TOP - 570m
CLIMB RPM @ 76KTS 2470
R.O.C @76KTS - 550FPM
CRUISE 2500RPM 1700FT - 100KTS

The numbers are more for comparison than absolute. I know I can get a few more knots for example in the cruise but I was as careful as I could be to fly in the same manner each run. Needless to say, the MDM will be staying on.

So if anyone is looking for a bit better take off and climb performance without giving up speed this might be the answer. It would be interesting to see how it would go pitched to 52".

oz502man wrote:..., had most of July off recovering from the ferry job and had a baby boy. ....

Don't know about all the weird anatomy of various animals "Down Under" ...but "UP HERE".... if a guy had a baby boy he'd need a LOT MORE THAN ONE MONTH off to recover!

gahorn wrote:

oz502man wrote:..., had most of July off recovering from the ferry job and had a baby boy. ....

Don't know about all the weird anatomy of various animals "Down Under" ...but "UP HERE".... if a guy had a baby boy he'd need a LOT MORE THAN ONE MONTH off to recover!

What can I say George - I heal quickly

Hello All,

Trying to educate myself as I've searched through as many posts on 8042 climb props and O300D. Either I don't quite understand or still not quite sure, so I'd thought I'd ask: is a 8042 prop legal or able to be on an O300D?

Thanks!

There is no STC to put an 8042 prop on an O-300D.
The STC for the 80 inch prop covers the 8 bolt prop and crank. The O-300D has a six bolt crank.
You could probably get a field approval for it but using (after buying) the STC tho.
I'd check with your FSDO before spending any money.

What pitch are you running now? I flattened mine to 51" and it does OK.

Hi
I asked the same question, and found the answer through the McCauley website, there is a PDF which has all the STCs holders.
In it I found the STC holder is The 170association !!!!!. It is included in the STC for the O-300D in the 170.
The 1A175SFC 80/40 is listed. There are several STCs for the 80/42 ,on 170s with the o-300D, but both ones I found are for
specific N number/ serial aircraft.

The prop for the O300C or D engine is the 1A175SFC 80/40 series.

I put the 1A175SFC 80/40 prop on my 170 for the ski season, and wow !! It is like a new plane !!!
It does 90 mph with skis but takes off in about 1/2 the distance. ( Hydraulic wheel skis )


John

If it's for a specific N number, it's a field approval (One time STC).

Do you have a link to that PDF?

Bagarre,

Currently has a McCauley IC172 EM7653.

John, so a general cover all STC for the O300D would be a 80/40 prop, but to get the 80/42 would need to do a one time field approval?

How does the 6 bolt vs 8 bolt come into play?

53B wrote:Hi,

The Kenmore STC does not cover the six bolt propellers. It only covers the 1A175DM propeller. I just installed a 1A175DM8042 propeller on my taildragger 172 and the speed decreased 15 mph. The climb rate increased 300 fpm.

Hope this helps!

That's the only STC that I know of to put an 80 inch prop on a Cessna 170 Land plane.
Since the STC calls out the 1A175DM propeller, which is an eight bolt patter, you can't install it on the O-300D. The O-300D uses six bolts for the prop.
So, you need a different propeller and that propeller wont be covered under Kenmore's STC.

Another idea is to pitch your current prop down to 51 inches and see if that's enough to satisfy you. much cheaper.

Bagarre,

That's how I saw it and thought, that the 80/42 was an eight bolt prop.

John, so you were able to put a six bolt 80/40 on your 170?? Is that how I am reading your post.

Appreciate the clarification and confirmation., thus far.

Hi
Go to http://www.mccauley.textron.com/MAG.pdf to down load the PDF, on page #413 , on line # 8
you will see that the 6 bolt prop is listed, ( 1A175SFC 80/40 ) for the 170B with the O-300D.

The STC # is SA7441SW owned by the 170 Association.

if the link does not work go the McCauley Propeller website, click on, products, select STC guide,
then down load the McCauley Application Guide , read the 640 pages,.... or just go to page # 413.
There you will see the STCs all listed.
I saw some 82 inch props on 170s.

STC SA7441SW is to install the O-300D and other six bolt crank O-300's (I don't know them all) onto the 170.
The STC does mention the 80" prop - for a seaplane.

I don't believe SA7441SW allows you to install the 80" prop on a land plane.