This is commonly called a “Hydraulic Mule” and is designed to bypass an engine-driven hydraulic pump in order to operate airplane landing gear and gear door systems without having the engine running in a maintenance environment.
I custom build these periodically and will post on Craigslist and Facebook for the Reno, Nevada area when I have one assembled and ready for sale. Just because you see this page doesn’t mean I have one available. You can contact me or find the CL or FB listing to be sure.
I will sell each pump for $2,500 for local pickup. It can be picked up near me at the Reno-Tahoe International Airport (KRNO) or the Carson City Airport (KCXP) in Carson City, Nevada to save on shipping costs. I can arrange shipping via uShip at the buyer’s expense, but this would have to be worked out well in advance of purchase.
Features:
- Heavy Duty 6-foot 12/2 power cord (120Vac)
- Adjustable Flow Rate from 0-2 GPM via Wolverine Flow Regulator (set to ~1 GPM in testing)
- Adjustable Pressure from 0-1500 PSI via Prince Bypass Regulator (set to ~1,000 PSI in testing)
- Custom 3D Printed (PETG) Return Reservoir Cap for all return lines
- Mounted to a hand truck for ease of deployment and transport
Pump operates on 120VAC (heavy duty extension cord needed) and has a 2.5 gallon reservoir tank. Bypass regulator and low-pressure return fluid line are ‘Teed’ to bring fluid back into the fill port of the reservoir.
The system is custom built, sold “as-is” with no warranty and ships complete as shown in the photo mounted to a hand truck for easier transport around the shop and is ready to go (just add hydraulic fluid). Unit can be transported upright (naturally) or laying flat (on its back) safely.
Video of my older and original, first generation mule operating the gear of my 1964 Centurion during its annual: https://youtu.be/kUsLZ71xTFI
Operation videos of the new unit for sale:
Flow test (digital flow meter NOT included): https://www.youtube.com/watch?v=Yj1SH1MTKEA
Pressure test: https://www.youtube.com/watch?v=arVp4k-McOk
The videos show it being tested as it will ship (digital flow meter NOT included), with a flow rate of ~1 gallon per minute (marked on the regulator) and the pressure bypass regulator adjusted to maintain ~1,000 psi. These are the typical settings for many aircraft hydraulic systems and can be fine-tuned to your needs in the shop. Be sure to adjust as needed for your application on a closed system capable of monitoring flow and pressure prior to connecting to an aircraft’s hydraulic system to prevent potential damage to the aircraft’s systems.
The high-pressure send and low-pressure return hoses are 10 feet in length and have been pre-fitted with 3/8″ NPTF swivel connectors which will likely need additional AN-to-NPT type adapters to match with the specific aircraft under service – easily available on Amazon. The high-pressure output fitting is a straight 3/8″ NPTF Male swivel fitting and the low-pressure return fitting is a 90° 3/8″ NPTF Male Swivel fitting. These are a very common size and easy to find adapters for.
Unique to my construction is a custom 3D printed reservoir cap I’ve designed to hold a ‘Y’ adapter for the return and bypass hydraulic fluid lines.
The system was tested with Mobil Aero HFA hydraulic fluid (modern 5606A equivalent), but will be drained prior to shipping. Be sure to re-fill or purge the residual with the fluid of your choice prior to use.
Manufacturer documentation of the pump/manifold system, bypass regulator and flow regulator will be included.
Also, the pump pulls several amps while running, so I recommend using the shortest possible extension cord to ensure reliable pump operation.