Rapco 215/216 vacuum pumps?

[Jim Burns]

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

Jim

[M]

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.

[Dave Butler]

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

[Jim Burns]

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

[M]

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

[Dave Butler]

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

[Jim Burns]

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

[Jim Burns]

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

[[email protected]]

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

[M]

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