Rapco 215/216 vacuum pumps?

Anybody useing the new "improved?" Rapco 215/216 vacuum pumps?

Jim

I replaced my 211 with an 215 during my last annual, because that 211
(still working) is at least 400 hr old if not much older, and I
couldn't find any reference to its age in my log book.

The 215 works fine. It suppose to have better cooling due to the
cooling fins. I can't speak to its life 'cause it has only been about
75 hours. I do however heard that good overhauled vacuum pumps on 4
cylinder engines can easily last about 1000 hrs, so a 400 hr
replacement interval can generally avoid failures. The life of vacuum
pumps on 6 cylinder engines is significantly shorter due to higher
rotation speed of the auxiliary shaft (?). If the vacuum pumps are
used to power de-icing boots they are even less reliable.

M wrote:
The life of vacuum
pumps on 6 cylinder engines is significantly shorter due to higher
rotation speed of the auxiliary shaft (?).

That's a new one on me. Why does the accessory drive spin faster on a 6?

Dave

Different gear ratio.... Lycoming 6 cylinders typicaly run a ratio of 1.3 :
1, so 700 hours is the most you should expect. Pretty good article on the
sacramento sky ranch site.
Jim


"Dave Butler" wrote in message
news:1145971786.778597@sj-nntpcache-5...
M wrote:
The life of vacuum
pumps on 6 cylinder engines is significantly shorter due to higher
rotation speed of the auxiliary shaft (?).

That's a new one on me. Why does the accessory drive spin faster on a 6?

Dave

See http://www.rapcoinc.com/pumplife.html

Jim Burns wrote:
Different gear ratio.... Lycoming 6 cylinders typicaly run a ratio of 1.3 :
1, so 700 hours is the most you should expect. Pretty good article on the
sacramento sky ranch site.

Thanks, Jim. I didn't find the article on the SSR site, but I believe you. Do
you know what the rationale is for making the accessory shaft spin faster on 6s?

Dave

Vacuum pump salesmen! nope, sorry I don't, but I'll add the question to
my list. I wonder if it could be that the fuel pump and the oil pump needs
to turn faster? do they? dunno, good research project.
Jim

"Dave Butler" wrote in message
news:1145999840.940424@sj-nntpcache-3...
Jim Burns wrote:
Different gear ratio.... Lycoming 6 cylinders typicaly run a ratio of
1.3 :
1, so 700 hours is the most you should expect. Pretty good article on
the
sacramento sky ranch site.

Thanks, Jim. I didn't find the article on the SSR site, but I believe you.
Do
you know what the rationale is for making the accessory shaft spin faster
on 6s?

Dave

Without an answer to "why", but interesting non the less, here are the drive
ratios for various accessories on the O-540 and IO-540 Lycomings per the
Lycoming OP Man.

Starter 16.556:1 CCW
Alternator 3.2:1 CW
Vacuum Pump 1.3:1 CC
Hyd Pump 1.385:1 CW
Tach 0.5:1 CW
Prop Gov 0.895:1 CW
Mag Drive 1.5:1 CW
Fuel Pump 1:1 CCW

Jim

These ratios may be different for dual magneto drives or wide cylinder
flange engines.


"Dave Butler" wrote in message
news:1145999840.940424@sj-nntpcache-3...
Jim Burns wrote:
Different gear ratio.... Lycoming 6 cylinders typicaly run a ratio of
1.3 :
1, so 700 hours is the most you should expect. Pretty good article on
the
sacramento sky ranch site.

Thanks, Jim. I didn't find the article on the SSR site, but I believe you.
Do
you know what the rationale is for making the accessory shaft spin faster
on 6s?

Dave

It's the Continental that spins the pump faster, according to
the Rapco guy in the seminar I took. I don't have the ratio handy, but
I might be able to scare it up.

Dan

See http://www.rapcoinc.com/pumplife.html

wrote:
It's the Continental that spins the pump faster, according to
the Rapco guy in the seminar I took. I don't have the ratio handy, but
I might be able to scare it up.

Dan