REFLECTOR: Vacuum pump

Wed Apr 10 11:38:34 CDT 2013

The guy that tried it said that the valve overlap in his engine (a V-6 like mine) caused pulses in the vacuum supply (he tapped off the intake manifold, no pump).  Not sure of the details, but something about that pulsing allowed moisture into the system. Trashed all his instruments. That is what I was referring to. Again, a bit vacuum accumulator could dampen out some of those problems, but seems to me just going electric is much easier and more reliable. I have had several vacuum pumps fail of different aircraft. I have never had an electric gyro go bad. 
YMMV. 

Kurt 

-----Original Message-----
From: Clayton Chase <chasec at gmail.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Wed, Apr 10, 2013 9:47 am
Subject: Re: REFLECTOR: Vacuum pump

How does the difference between a vacuum pump and a venturi affect moisture?   The air enters the system through the other end.   I can understand that inconsistent vacuum provided by a venturi could cause damage, but you could do workarounds that should help.  An electric vacuum boost pump that is on when the landing gear is down (and airspeed is low and the venturi is not providing good suction) and a good vacuum limiter  should resolve most of the issues. 
On Apr 10, 2013 8:12 AM, <nmflyer1 at aol.com> wrote:

Yup, Had those in my 56 Chevy too. They would almost come to a stop when you hammered the throttle. 

For me, I just went all electric. I didn't want to deal with the vacuum issue and length of runs. So far, so good. 

Kurt 

-----Original Message-----
From: Robert Wood <slvegl99 at aol.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Wed, Apr 10, 2013 8:47 am
Subject: Re: REFLECTOR: Vacuum pump

Yeah, I was just reflecting on my '37 Ford wipers.

Bob Wood

Sent from my iPad

On Apr 10, 2013, at 10:44 AM, nmflyer1 at aol.com wrote:

That has been tried & failed. Between moisture and pulsing (unless you have a Big vacuum tank with a dryer). Last guy that I know tried it had to replace all his instruments. 

Kurt 

-----Original Message-----
From: Robert Wood <slvegl99 at aol.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Wed, Apr 10, 2013 8:40 am
Subject: Re: REFLECTOR: Vacuum pump

How about a line from the intake manifold?

Bob Wood

Sent from my iPad

On Apr 10, 2013, at 10:33 AM, "Richard J. Gentil" <richard at naples-air-center.com> wrote:

Lol!!!

That would just look so wrong in so many ways!

Richard 

Sent from my iPhone 5

On Apr 10, 2013, at 10:10 AM, Mark Magee <edjonesbrady at gmail.com> wrote:

I just replaced mine and tried to figure a way to eliminate it... Anyone using a venturi??? With our speed they should pull hard... 
They would look a little 'retro' but would be easier than replacing these disposable Rapcos.
Mark

On Wed, Apr 10, 2013 at 8:51 AM, Richard J. Gentil <richard at naples-air-center.com> wrote:

Bob,

Don't forget to blow out the vacuum line and clean/replace the air filter.

Richard

Sent from my iPhone 5

On Apr 10, 2013, at 8:38 AM, Robert  Wood <slvegl99 at aol.com> wrote:

> Monday on a flight with my Velocity XL with a Lycoming IO 540 I experienced a vacuum pump failure. Any secrets in the procedures for removing and replacing it? Is the drive shaft to be lubricated when the replacement is installed?
>
> Bob Wood
>
> Sent from my iPad
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