PROPULSION SYSTEM
PROPULSION SYSTEM: Please comment on the corrosive environment and the limitations on performance and maintenance and increased cost of operation it imposes. What has been done or can be done to the engine to increase the resistance of the engine in salt water environment (salt in the air), in order to keep service cost at an acceptable level.
NOISE EMISSION
NOISE EMISSION: Noise emission is apparently higher than that of a conventional sea craft. Please confirm internal and external noise emission data. There is a concern that even at slow speed the engine noise may well exceed that of conventional marine engines.
TAKE OFF DISTANCES, SPEED AND PROCESS (AIDS)
TAKE OFF DISTANCES, SPEED AND PROCESS (AIDS): Please inform take-off distances and speed in relation to payload. Also, please explain what the main technological advantages of the SF-08 in regards to the take-off process are. How the problems of thrust mismatch between take-off and cruise were overcome? Are there any take-off aids in place? What is the take-off power requirement of the SF-08 in relation to payload? Please confirm the highest wave possible for take-off and landing.
Take-off-Distances, Speed and Process
The take-off-distance of the full loaded craft (900 kg payload) is about 700 m, if the payload is only 200 kg the take-off-distance is about 500 m.
The advantage of the craft in the transition and take-off-mode is the design of the hull form which creates only a low hydrodynamic resistance and following from this a low take-off-speed below 100 km/h.
To achieve extremely short take-off-distances of lesser than 400 m with the fully loaded craft we designed under-water-foils. The successful application of this type of foil was proved on our 2-seater-craft.
The foils have to be arranged on the hull in the position of centre of gravity of the empty craft.
In cases, the underwater-foils are used, there is no mismatch of thrust between take-off-mode and flare mode. Without foils the thrust has to be reduced from about 85 % of maximum engine power to about 50 % immediately after take-off. This procedure can be simply handled.
The take-off-power without foils is about 180 kW, the thrust is about 5500 N then.
The greatest wave high for take-off is about 1 m. After successful take-off the wave high is not important because the craft can move in any altitude above the wave crests (maximum altitude about 30 m).
SAFETY - SENSORS AND NAVIGATION
SAFETY - SENSORS AND NAVIGATION: Sea state needs to be measured to determine the safe operating altitude. Obstacle detection is also extremely important for WIG craft safety. Systems must be able to detect rogue waves, small crafts and other hazards pertinent to a craft operating at low altitude and high speed. What are the sensors available in order to guarantee safe operation of the SF-08?
SAFETY – IMPACT WITH WAVES
SAFETY – IMPACT WITH WAVES: What are the limitations and structural strength of the hull in regards to survivability to wave impact?
GROUND EFFECT
GROUND EFFECT – It was mentioned in one of SeaFalcon’s presentation that the SF-08 can fly in ground effect at a altitude of ˝ of the wing span. Most studies show that the cruise height limitation on WIG crafts is approximately 10% to 30% of the wing span, and that at higher heights the theoretical efficiency is reduced to that of an aircraft. Which number is correct? If SF-08 numbers are correct, what improvements were made to achieve ground effect at an altitude of ˝ of the wing span?
CLASSIFICATION
CLASSIFICATION – The SeaFalcon SF-08 will be classified as a Class B WIG Craft, correct? Is there any system in place to avoid sustained flight out of ground effect?
MAINTENANCE
MAINTENANCE – Some expect that the maintenance requirement for WIG crafts would be higher than similarly sized aircrafts. Engines and structure would require frequent washing to protect it from corrosion damage. Dry dock may be mandatory in order to increase craft life. The craft will need regular dry docking to perform hull cleaning and maintenance. What are your comments on that?
PAYLOAD, RANGE AND SPEED
PAYLOAD, RANGE AND SPEED – What is your latest update in regards to payload, range and speed for the SF-08.
TURN RADIUS
TURN RADIUS IN DISPLACEMENT MODE AND IN GROUND EFFECT – What are the maneuverability specs for the SF-08 in displacement mode and in ground effect. Also, while in ground effect, will the SF-08 be able to make banked turns, or will it perform skidding turns?
STABILITY
STABILITY – Won’t the position of the passengers and payload inside the SF-08 affect its center of gravity and consequently its stability?
TAIL PLANES
TAIL PLANES – What is the area of the tailplanes in comparison to the area of the main wings?
OVERCOMING PITCHING MOMENT
OVERCOMING PITCHING MOMENT – How does the SF-08 overcome pitching moment?
TYPE OF WIG CRAFT
TYPE OF WIG CRAFT – There are a few known types of WIG crafts: Ekranoplan, Ram Wing, Tandem, Lippish… Where does the SF-08 fit in?
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