The Sud Aviation/Aérospatiale SA-610 Ludion (Ludion – Cadet) was a tiny, unorthodox VTOL aircraft demonstrated at the 1967 Paris Air Show. It consisted of little more than a chair, behind which were mounted two downward-pointing augmented rocket engines with control provided by thrust vectoring. The Ludion was intended to carry its pilot and 30 kg (66 lb) of equipment up to 700 m (2,300 ft) at an altitude of up to 200 m (600 ft).
The unusual powerplant consisted of a monofuel de-composition chamber fed with pressurised isopropyl nitrate (AVPIN), ignited by a catalyst. The high pressure gasses produced in the de-composition chamber were fed to two augmentor tubes, built by Bertin, either side of the pilots seat, angled slightly outwards. As the gasses entered the augmentor tubes through rocket nozzles, thrust was augmented by inducing airflow through the ducts which acted as aero-thermo-dynamic ducts, due to the heat and kinetic energy added to the flow through the ducts, and the carefully shaped exhaust nozzles.
SA-610 Ludion Powerplant: 1 × SEPR S178 isopropyl nitrate (AVPIN) decomposition gas generator with augmentor tubes Length: 1.95 m (6 ft 5 in) Width: 1.485 m (4 ft 10 in) Height: 1.6 m (5 ft 3 in) Empty weight: 90 kg (198 lb) Gross weight: 170 kg (375 lb) approx Capacity: payload 30 kg (66 lb) Crew: 1 Ceiling: 700 m (2,297 ft)
This new helicopter, which was brought out as a product of Sud Aviation, first flew on 10 May 1957 (F-WIEA). It was introduced to the public during the French International Air Show at le Bourget soon afterwards. It basically an Alouette II with an Artouste engine, covered fuselage and executive cabin seating 5 occupants including the pilot, by the well-known expert Loewy.
Streamlining gave the Gouverneur improved cruising speed.
Both the main and the anti-torque rotor are taken from the Alouette, but to protect the latter, a bow-shaped tail skid is provided. Much thought has been given to making the Gouverneur’s cabin as comfortable as possible, particularly by means of sound-proofing.
Formed 1 March 1957 by amalgamation of Ouest-Aviation (SNCASO) and Sud-Est Aviation (SNCASE). Main responsibility was further development and marketing of highly successful S.E.210 Caravelle twin-jet airliner, first flown in 1955, and Alouette series of helicopters. Continued also development of S.E.5000 Baroudeur, S.O.9050 mixed-power interceptor and widely used S.O.4050 Vautour twin-jet multipurpose aircraft. Frelon series of large turbine-powered helicopters developed after first flight in February 1959, and Super Frelon flew December 1962, setting new world records. In 1965, Morane-Saulnier became a subsidiary of Sud-Aviation. Design leadership in A300 European Airbus assumed and diversification into non-aeronautical fields undertaken. Jointly with Nord Aviation made Corvette light rear-engined jet transport.
On January 1st, 1970 became major component of Aerospatiale, with Nord-Aviation and SOCATA, and the missile manufacturing company, SEREB.
These engines are designed specifically for the recreational aircraft market and are manufactured in Hamilton, New Zealand. Subaru EA81 engines are a favoured option for many recreational aircraft builders, however although these engines are light, rugged and dependable, they suffer a number of shortcomings which limit their true potential in this environment. For example, Subaru designed the original EA81 engine with siamesed inlet and exhaust ports. This, coupled with a long and poor flowing inlet manifold, significantly restricted the engine’s output (115hp@5500rpm).
The SUB4 company have addressed this issue by designing and manufacturing new dual port cylinder heads which feature two sparkplugs per cylinder. These high flow, high compression heads utilise larger inlet valves which when used with SUB4’s revised camshaft design and tuned inlet manifolds, combine to significantly increase the engine’s BMEP (brake mean effective pressure), delivering a wide, smooth torque band and 60% more (dyno proven) horsepower. SUB4 engines are also supplied with a full electronic dual ignition system and a compact 4 into 1 exhaust manifold. These modifications make the SUB4 engine in the recreational aircraft market with an excellent power to weight to cost ratio.
After 2 years R&D, the company was at Sun N Fun 2000 with their SUB 4. While the basic block from the EA81 is used the rest of the engine has undergone extensive changes and or modifications.
The SUB 4 Port heads have been modified to give “one port per valve for both inlet and exhaust to allow for tuned length of induction and exhaust. The heads are cast in ASTM 356 aluminium alloy, which is heat treated and CNC machined. The heads come with bronze valve guides, 42 mm inlet valves x 7 mm valve stems. Performance valve springs, match cam and h.p. option. The water outlet fitting accepts a standard automotive water hose. Each head set is supplied with a camshaft ground to match the h.p. option.
The rocker covers are cast ASTM 356 alloy, with a finned design to aid cooling. A “O” ring is used for sealing. One cover is set up as the oil filter while the other as the breather.
The SUB 4 reduction drive has three cases cast in ASTM 356 heat treated aluminium. The intermediate case can be rotated 180 degress to allow for props in an up or down installation. The reduction gears are manufactured from EN39B case hardened to 60 Rockwell C. They are 11 degree helical, and 40 mm meshing width incorporating a radiused oil relief groove. The PSRU can be geared to 0.455 or 0.556.
The Propeller Speed Reduction Units (PSRU’s) suit the EJ-20, EJ-22, EJ-25, EG-33, and EZ-30 (H6) series of Subaru engines.
An aluminum flywheels incorporating a high tensile steel ring gear is used, with a rubber cush drive on the flywheel. Ratios of either 1.8 to 1 or 2.2 to 1 are available.
All of the components are available complete or as separate units for the do it yourselfer!
This version can be retrofitted to Sub4 125hp specifications.
Sub4 Performance Aeromotive Parts 25 Euclid Avenue PO Box 10004 Te Rapa, Hamilton New Zealand Phone: 64 7 849 3814
Castech is a Hamilton, New Zealand, non-ferrous foundry and cnc machineshop, established in 1986. The reduction drives and engines plus components have been sold under the brand name Sub4. The new drive are sold under castech but branded according to the customers requirements.
Areas of expertise include Aluminium casting to max 80kg. CNC machine centre and CNC lathes. Welding and fabrication. Machine assembly.
Composites capabilities are increasing with a materials engineers who has a masters degree in composites.
