Vacuum Pump Adapters

Patent Pending

Although many experimental aircraft have opted for glass panel displays (EFIS), most serious IFR pilots insist on tried and true gyros if only as backup. On the other hand, many pilots simply prefer the simplicity and reliability of gyros. No need for a backup battery, no need to assimilate complex programming, etc.

Unfortunately, given the design of vacuum pumps, it has always been difficult (to say the least!) to install a vacuum pump on an experimental engine. After much testing, we have designed a simple, reliable adapter for running a dry vacuum pump on several auto conversion engines: Corvair, Subaru, VW.

Given that most vacuum pumps have an effective maximum speed of 4000 RPM, it is important to match the maximum crankshaft RPM to the proper reduction gearing. In the case of a direct-drive Corvair engine with a maximum speed of 3200 RPM, the addapter can be run directly off the crankshaft (see photo at right) or by a belt system (shown below) with no reduction gearing. However, if your engine uses a PSRU or any type of gearing that allows an engine RPM above 3500, we will provide the appropriate reduction gearing for your installation -- just send us your maximum engine RPM.

Although we currently offer complete kits only for the Corvair engine, homebuilders can modify the supplied brackets for their own installation.

A few useful details:

- the designs are for DRY vacuum pumps and some modifications to the bracket may be required for wet pumps.

- if your engine mount is unique or deviates significantly from the standard mount, there may be interference with other components

- although dry vacuum pumps have proven their reliability over the years, we strongly recommend the installation of a backup vacuum source if you intend to fly in IMC. We have designed affordable alternatives: our own vacuum backup system for only $135 as well as a vacuum failure alarm for $85.

Compare to Revmaster's vacuum pump adapter.

Corvair Direct Drive Adapter Kit (vacuum pump not included) $130.00

Universal Belt Drive Adapter Kit (vacuum pump not included) $180.00

For pilots seeking an affordable alternative to purchasing a new vacuum pump, we recommend our friend Joe who has a variety of good used pumps from salvage aircraft (as well as a number of other components). He sells these pumps for only a little more than the core charge of a rebuilt pump and they often have significant life left in them. When it wears out, you send it in and will get most of your money credited back for the core. Joe can be reached at jenkinsair@aol.com or at (302) 697-7743.