Operating on Ice

Hovercrafts have ice-breaking characteristics. Operators should avoid snowmobile trails or other special activity areas where the hovercraft may break or weaken the ice surface. This will typically happen when the ice is less than 1.5 inches thick. To minimize the risk of breaking ice, speed should be maintained above 15 mph. Broken ice can become hazardous to the crafts skirt system. Broken ice chunks can be very sharp and can cut the vinyl skirt if proper care and procedure are not followed.

 

Stopping on ice:

Hovercrafts have very little friction when travelling over ice. Reducing power will help to slow forward momentum. Typically this will not be enough to slow or stop the craft in a short distance. There are four methods of slowing or stopping over ice: 1) Side slide method: In this method the craft is steered from side to side while maintaining the direction of travel. Turning the craft from side to side increases the air drag on the craft helping to decelerate. 2) 180 reverse stop method: In this method the craft is quickly turned from its forward coarse 180 degrees in the opposite direction of travel. Partial or full thrust can be applied causing rapid deceleration. This maneuver should not be performed over 35 mph IAS. 3) Ditching method: In this method the operator quickly reduces power allowing the crafts landing skids to come into contact with the surface. The craft will then slide to a stop. The craft must be fitted with upgraded landing skids for this method to be effective over most ice. 4) Combination method: In this method the pilot will use a combination of the above maneuvers to successfully slow the craft.

 

For example: If the craft were travelling at 45 mph over ice and needed to stop, the pilot may use a combination of the above methods. First the pilot would begin by side sliding the craft to reduce excessive speed. When the craft decelerates to under 30 mph a 180 reverse stop may be executed.

Experienced pilots typically use the combination method to stop.

 

 

Operating Over Water

Accelerating:

Rotate the throttle counter clockwise to increase engine RPM. From a standstill the craft must be slowly be brought up to the accelerating power setting (3,600 RPM) until the craft is over hump. Immediately after the craft has accelerated over hump speed the cruise RPM setting should be adjusted.

 

Trimming the craft:

While the craft is accelerating the elevators should be in the nose down position. Typically the operator should be slid slightly forward on the seat. This reduces spray and drag. After cruise speed has been reached; proper trim must be attained. The operator should move into a position on the seat that keeps the hovercraft level. If up elevator is required to keep the craft level, a change in balance is necessary. Begin by moving ballast items such as tool bags or cargo toward the rear of the craft until proper trim has been achieved.

 

Turning (slow speed):

Slow speed turns allow the most precise maneuverability. Turns should be planned as far in advance as possible. Entrance speed into a turn should be between 11 – 30 mph. Higher speed turns will use a larger radius while slower turns can be accomplished in a very small area. In this example the entrance speed is 15 mph. Enter the turn above plane speed. Apply pressure on the handlebars to achieve the desired turn angle. After the turn has begun apply slight pressure in the opposite direction to stop rotation. Continue the turn by adjusting the throttle and rudder position to keep the craft on course. The goal is to complete a controlled turn with the least amount of water spray possible. 

 

Turning (high speed):

Higher speed turns (30+ mph) will use a large turning radius. Turns should be planned as far in advance as possible. Apply slight pressure on the handlebars to achieve the desired turn angle. After the turn has begun apply slight pressure in the opposite direction to stop rotation (at higher speeds this may not be necessary). Continue the turn by adjusting the throttle and rudder position to keep the craft on course. The goal is to complete a controlled turn.

 

Stopping:

Hovercrafts have very little friction when travelling over most surfaces. Reducing power will help to slow forward momentum. Typically this will not be enough to slow or stop the craft in a short distance. There are four methods of slowing or stopping over any terrain: 1) Side slide method: In this method the craft is steered from side to side while maintaining the direction of travel. Turning the craft from side to side increases the air drag on the craft helping to quickly decelerate. 2) 180 reverse stop method: In this method the craft is quickly turned from its forward coarse 180 degrees in the opposite direction of travel. Partial or full thrust can be applied causing rapid deceleration. (WARNING: This method should not be used over sticky mud terrain). This maneuver should not be performed over 35 mph IAS. 3) Plow / Ditching method: This method should only be used while the craft is aimed within 15 degrees of its straight line course. In this method the operator reduces power allowing the crafts plow plane or landing skids to come into contact with the surface. Contact will increase drag resulting in a controlled deceleration. The operator can vary the degree of deceleration by coordinating fan RPM and position of the elevator. 4) Combination method: In this method the pilot will use a combination of the above maneuvers to successfully slow the craft.

Hovercrafts are not equipped with brakes. The pilot must always keep this in mind as he is travelling over different terrains and in close proximity to other operators.

180 reverse stop method should not be used over sticky mud or any terrain that may stick to the skirt. It is possible for the craft to stop suddenly while travelling sideways over mud causing a rolling moment.

 

Hovercraft will decelerate at the same rate as a boat when operating over water.

All maneuvers should be performed with the goal of staying in control and maintaining low water spray throughout all operations. Low spray keeps component maintenance and repair to a minimum while increasing comfort and vision.