New bird just in time for Christmas

[wyandot jim]

So you've got a Bendix Pressure Carburetor....

This article was found on the Aero Commander Website (www.aerocommander.com). Following these guidelines will insure a long and peaceful life with the PS5-BD. Especially follow the rule about putting the mixture in “park” when the engine is not running. Many thanks to Chris for the most useful information.
© Chris Schuermann - 1996

If you own an airplane built in the 40's or 50's you just might also be the owner of one of
aviation’s most bizarre pieces of hardware - the Stromberg (Bendix) pressure carburetor.
This little marvel of engineering is the predecessor of fuel injection. Although technically
classified as a carburetor, it has no float system, and meters pressurized fuel much like a
throttle-body injection system.

The PS5 series carburetor can operate installed at any angle, and may even be used on
turbo-supercharged engines. I have heard that it is even possible that it may have been
configured for a "blow through" system although I can't find any literature on that
application.

Some interesting notes

The Bendix pressure carburetor has several unique traits.
It has an airflow-operated auto-enrichment valve, which provides an extra rich setting at
full power. It is important to maintain full throttle during the initial climbout using this
carburetor. A reduction in throttle will cause higher EGT/CHT than desired because the
carburetor is designed to provide an optimum lean mixture except at full throttle.
Many models have an automatic mixture control. The mixture knob is left in the full rich
position for all flight operations. A nitrogen-filled bellows assembly automatically
compensates for both altitude and temperature!

Complex too!

I've yet to see any carburetor as complicated as a pressure carburetor. It has more little
chambers, diaphragms, and passageways, etc. than would seem reasonable. That
noted, they run remarkably well when in good condition. They are also quite reliable
once rebuilt with the new synthetic diaphragms.

To tell if you have the new diaphragms, look at the edges of many pieces of the
carburetor. If you see what looks like black rubber gaskets, you have the older rubber
diaphragms. If you see orange, then you have the new synthetic ones.

Don't leave the mixture at idle cutoff!

A pressure carburetor needs to have the mixture control placed at the "park" position
after shutdown. If left in the "idle cutoff" position for any length of time, the diaphragms
will be damaged!

(Ed. note: After speaking to Mike’s Metering Service, below, the mixture
can be left in ANY position after shut down as long as the new ‘orange’ diaphragms are
installed.)

Fuel pressure is also critical for a pressure carburetor. Most are set at 14 psi ± 1 psi.
Outside of this range the carburetor will fail to meter correctly.

If you get more than a 10 RPM rise during shutdown, the carburetor needs to go to a
shop. Also, if your bird isn't VERY easy to start, get the carburetor to a shop. My
experience is that engines with a Bendix carburetor should be VERY easy to start - hot or
cold. A very slight problem with the carburetor will cause hard starting.

There are only two principal adjustments that may be made without a flow bench: the
metered fuel pressure, idle mixture and idle speed. Don't mess with ANYTHING on
this carburetor if you don't know what you're doing. Turning almost anything affects
something else....

If you'd like a reference for a pressure carburetor guru who really knows his way around a
PS-series carburetor, feel free to drop me a note. A PS5BD carburetor exchange is
about $1200 ($1600 now!). The diaphragm kit is VERY expensive, and it takes a lot of
time to properly set one up on a flow bench...
Chris

PS- The reference Chris mentions above is:
Mikes A/C Fuel Metering Service, Inc. ($60/hr)
9406 E. 46th Street North
Tulsa, OK 74117
(91 838-6217
(91 838-7047 fax

or

PRECISION AIRMOTIVE ($75/hr)
3220-100th Street, SW #E
Everett, WA 98204
(360) 651-8282
(425) 347-2800 Manuals

[rsrguy3]

Wow! Thanks Jim. I seriously hope it's not 5k to overhaul it! But the swap looks like the way to go. If the feulie stc will cover this motor with injection that will be the way to go.

[Jim Hann]

Pretty bird! Most of my Beech time is in Barons but I wouldn't mind a Bonanza, my wallet says stay with the Pacer.

[yarddart]

Great looking airplane sure to check for corrosion around bulkheads good luck

[pa20]

And...When you get it on jacks, pay attention to the gear strut trunions. Most older Bo's that I worked on were worn pretty badly from years of use and lack of grease. Also, be sure to have a good look at the alternate air door. Used to find worn hinges all the time. If that door comes loose, the next thing you will hear is deafining silence as you are sucking the wool off the seat covers!
Love the Bonanza's, but they need serious TLC to keep them in good shape!

[rsrguy3]

The bird is in awesome shape! It's been sitting at 7200 ft in dry air high desert for 25 plus years. ZERO corosion, and new paint 1 year prior to storage, even then it was hangared . The IA is a big bonanza aficionado and knows them well. I'm in good hands for sure. Jim, my budget says tripe only as well but this is retirement money towards my ratings, so the bird will get sold when I take on those flying jobs that don't pay dirt, we bought it well.

[Jim Hann]

Jim, my budget says tripe only as well but this is retirement money towards my ratings, so the bird will get sold when I take on those flying jobs that don't pay dirt, we bought it well.

I did mine starting in high school the hard way, renting and college. Only took me 21 years to pay off the school debt after the last graduation! I will say that 30 years in (yep) and about 14,000 hours later I'm still having a great time sitting in the corner office with the constantly changing view.

[rsrguy3]

Can't wait!

[Jim Hann]

Good luck!

[rsrguy3]

Saw your bird in the mag Jim. Cool deal congrats.