ln 1963, Max Dreher began work on the design of the youngest member of his turbin Family, the T.J.D.-76 Baby Mamba.
It was designed to power a sailplane and had a static thrust of 55 lbs. He tried to keep it as simple and light as possible. No gear reduction was used and it had a free-spinning rotor. He selected a single-stage mixed flow compressor, an annular combustion chamber and a single stage axia-flow turbine for the basic layout.
The whole job, from the begining to end, took about 3600 hours. Then the Baby Mamba had logged many starts had many hours on the stand and in flight tests.
At front. Air flow 0.50 kg (1.1 lb)/sec.
Single-stage mixed-flow. Single 17-4 PH stainless steel impeller with sixteen vanes. Splined to shaft and supported in two ball bearings. Mixed-flow two-stage diffuser of 347 stainless steel. Pressure ratio : 2.8 : 1
Of 2024 aluminium alloy and 347 stainless steel.
Annular type with Hastelloy X outer casing and flame tube. Vaporising system with fuel/air pre-mix. One spark plug in flame tube.Fuel system: Manual with pressurised fuel supply, or electrically-driven fuel pump. Fuel pressure 5.52 bars(80 lb/sq in). Automatic system for drone applications. Fuel grade: Kerosene or petrol.
Nozzle guide vanes
Single axial stage, with sixteen investment-cast vanes in Stellite 31.Turbine: Single-stage axial-flow, with nineteen integrally-cast blades, of Inconel 713 LC. Gas temperature 770°C before turbine, 675°C after turbine, at continuous cruising power.
Fixed type, with jet pipe and cone of Hastelloy X. LUBRICATION: Air/oil mist system with total loss, using bleed air equivalent to 2.5 per cent of total mass flow.Capacity 1 litre (2 US pints).
MIL-L-7808E (Turbo 15).
Two rigid connections on diffuser section and one flexible connection on turbine section.
Compressed air 1034 bars (150 lb/sq in), via three nozzles driving turbine wheel.
TJD 76C Technical data
|Manufacturer||DREHER Engineering Company|
|Diameter||151 mm||5.94 in.|
|Length overall||416 mm||16.38 in.|
|Not equipped||6.4 kg||14.1 lbs|
|Equipped||10.0 kg||22 lbs|
|Max RPM||96 000 t/mn||96,000 rpm|
|Thrust at max RPM||245 N||55 lb|
|Thrust max continuous||200 N||45 lb|
|Thrust at idle RPM||N||lb|
|Pressure ratio||2.8 / 1|
|Max Flow||500 g/s||1.1 lbs/sec|
|Max continue EGT||675 deg.C||1247 deg.F|
|Specific fuel consumption||0.6 kgs/kg/s||1.35 lbs/lb/s|