Diameter:  111mm
Length:  235mm
Thrust:  75 Newtons (16.8 lbs)
Max revs:  115,000 rpm
Weight:  1.1 KG (2.42 lbs)


This engine was developed by Geoff Vaizey developed from the earlier PT 35 design that is now superseded . The engine takes a similar form to the car turbo-charger based engines that have been recently developed. Geoff has however introduced some new ideas and it is hoped that they will add to the knowledge about small gas turbines and make them more reliable. The main way that the engine differs from the KJ66 is that the pre-loading of the bearings is applied to the outside of the front bearing and not to the outside of the rear bearing. The preload is via a special spring washer which saves space and weight and reduces the number of components. The air supply to the bearings is fed from in front of the front bearing and there is no air cooling hole in the main part of the bearing tube. The bearing tube is fitted in a screw thread rather than being held by bolts. The combustion chamber is specially shaped to assist with the air flow through the engine.


The diffuser assembly is made up from aluminium . The diffuser is available as a CNC component or can be made on a rotary table or on the lathe ( given some ingenuity) . The front cover is in 2 parts and both are machined from the solid. The outer cover could be spun or machined from solid. The central tube is Stainless steel and has one end treaded fro attachment to the diffuser plate. The ball races that are used are the familiar 608 bearings and the best results will come from the ceramic bearings that have only recently become The outer can is the familiar gas canister and the Combustion chamber is in stainless steel. The Nozzle Guide Vanes are in either cast Inconel 713 or stainless steel.


The compressor is the high through-put KKK 2038 wheel, which is currently the most favoured compressor wheel.

Turbine wheel

The turbine wheel is cast in Inconel 713 and is fitted onto a taper to ensure that an accurate fit is obtained during the life of the engine. The engine requires left hand threads for both ends of the shaft.


The bearings are ISO 608 22mm x 7mm with an 8mm bore. It is possible to use the standard C3 grade bearings but best results will come from Ceramic bearings.

PT - 75 Miniature Gas Turbine

This professionally designed engine is the culmination of 4 years development, 7 prototypes, and many hours of flight testing. The use of high speed ceramic bearings with an all new series cooling and lubrication system ensures long bearing life. The Turbine and Nozzle Guide Vanes are cast in Inconel 713

Parts not now available