The Murphy Builders Site

Hello Amphib Float Builders/Flyers:

I am going to be fabricating the pulley brackets for the MAM Amphib
floats and have a question on the size of said pulleys.

I received 2.50 inch OD x 1.90 inch ID (Part Number BB 128) pulleys with
my 1800 float kit, The plans (Fig. 15.2. show that the brackets will
fit these pulleys.

I have noticed similar float installations (not MAM) that use 2.00 inch
OD pulleys. One supplier sells a float water rudder pulley that is 1.50
OD. Browsing through Aircraft Spruce catalog,, there are two Special
Pulleys made from UHMW material with stainless inserts. 1.50 inch OD and
2.00 OD. In the description, it is mentioned that the 2.00 inch "fits
DeHavilland Beaver floats".

Is the 2.50 OD size pulley supplied by MAM used because of the (almost)
90 degree angle the cable makes or can one substitute a smaller (2.00
inch OD)?

What is the correct outside and inside diameter of the pulleys used on
the MAM 1800 Amphib floats as well as the rudder retract pulley at the
forward floor centerline?

If the smaller 2.00 inch OD is the pulley of choice, I can purchase
correct ones and make a new drawing to fit the new diameter. Are there
any gotchas (other than different shaped brackets) if a 2.00 inch OD
pulleys are used? Part Numbers?

Comments? Suggestions?

Thanks in advance.

Terry Dazey
Rebel 662
Lake Tapps, WA U.S.A.





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Terry I ran into this on my Prebuilts that I installed to DJK last summer as
well. I made all the brackets and then opened the pulley package to find for
some reason they shipped BB128's with all our prebuilts. With a bit of
"massage" work I made things work well. The attach bracket drawing in the
manual is for 2" pulleys and they work great as well. Why spend more money
that you don't have to. Use the BB128's supplied and just remember to make
the brackets a tad longer to keep the pulley off the struts.

Wayne

----- Original Message -----
From: "Terry Dazey" <dazey@earthlink.net>
To: "Murphy Group" <rebel-builders@dcsol.com>
Sent: Monday, April 03, 2006 3:30 PM
Subject: [rebel-builders] 1800 Amphib Float Pulley Size

Hello Amphib Float Builders/Flyers:

I am going to be fabricating the pulley brackets for the MAM Amphib
floats and have a question on the size of said pulleys.

I received 2.50 inch OD x 1.90 inch ID (Part Number BB 128) pulleys with
my 1800 float kit, The plans (Fig. 15.2. show that the brackets will
fit these pulleys.

Hi Wayne:

The drawing in my manual shows that the brackets will fit the 2.5 inch

pulleys that I received. Everything matches. I was just curious why they

such large pulleys and was wondering what the best pulley size is. Maybe

factory ordered a stock of them with the wrong size (the 2.5 inch O.D.

or maybe they ordered 2.5 OD for a "one size fits all" application.

From your comment, I am thinking that the 2 inch OD is the pulley of

that is what has been used previously. I don't mind spending a few extra

get the correct parts on my Rebel. Besides, the smaller pulleys would make

plane go faster . . . haha!

Thanks for the information Wayne.

Terry Dazey
Rebel 662
Lake Tapps, Washington USA

"Wayne G. O'Shea" wrote:

Terry I ran into this on my Prebuilts that I installed to DJK last

well. I made all the brackets and then opened the pulley package to find

some reason they shipped BB128's with all our prebuilts. With a bit of
"massage" work I made things work well. The attach bracket drawing in

manual is for 2" pulleys and they work great as well. Why spend more

that you don't have to. Use the BB128's supplied and just remember to

the brackets a tad longer to keep the pulley off the struts.

Wayne

----- Original Message -----
From: "Terry Dazey" <dazey@earthlink.net>
To: "Murphy Group" <rebel-builders@dcsol.com>
Sent: Monday, April 03, 2006 3:30 PM
Subject: [rebel-builders] 1800 Amphib Float Pulley Size

Hello Amphib Float Builders/Flyers:

I am going to be fabricating the pulley brackets for the MAM Amphib
floats and have a question on the size of said pulleys.

I received 2.50 inch OD x 1.90 inch ID (Part Number BB 128) pulleys

my 1800 float kit, The plans (Fig. 15.2. show that the brackets will
fit these pulleys.

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I've got the 2 and a 1/2's on mine Terry and it didn't slow me down one darn
bit! )))

Wayne