When we travel it is common to travel even short distances by aeroplanes powered by jet engines, but what happens when a jet engine needs to travel? Unlike people a jet engine requires to be loaded onto a precision transportation cradle that allows it to be moved securely to worldwide destinations by road, rail or air.
One such transportation cradle is the "T57 Roadrunner" designed as a multi-functional and modular stand for Trent 500 and 700 aero engines. It has several configurations, which include air freight (standard IATA airfreight pallet), long distance towing, Storage and road transport. It is designed as a self-supporting structure that maintains position accuracy of the mount points under the handling loads, while distributing the weight elements to a level that allows them to be easily and safely manipulated.
The Trent engine family is designed to power the new generation of wide-bodied jets. The Trent 500 has been specifically designed to meet the requirements of the four-engine Airbus A340-500 and -600. The Trent 700 meets the requirements of all members of the Airbus A330 family.
When an aero engine is loaded onto the stand it is positioned in a location cradle, which is lowered onto its transportation points. For the T57 the lifting and lowering of the engine had to be performed by a mechanical height adjustment system optimised for speed and ease of use with inter-locking controls and a mechanism to prevent back drive. The system also had to provide low maintenance and long life. To meet these requirements a three point lift system was devised using three screw jacks connected in a system by bevel gearboxes, couplings and drive shafts. The system was designed to be quick and easy to use by hand operation while being self-locking.
For the screw jacks the 50kN E-Series metric machine screw jacks were used of the type KTE1805. Keyed screw jacks were used, as there was no external guiding mechanism on the lifting frame. The 24:1 gear ratio combined with the 9mm lead on the screw provided a mechanism that was self-locking and minimum torque input for hand operation. As the screw jacks are exposed to the elements the worm shafts are chrome plated and the screw is protected by a PVC bellows boot.
Joining the screw jacks together in the system were two Neeter Drive range-N series 35 bevel gearboxes. A 3-way solid shaft model 35341M with 1:1 gear ratio was chosen for its ultra compact size and high efficiency.
In operation the screw jack system has provided a reliable and precise mechanism for lifting and lowering aero engines in and out of the transportation cradle.