Elevator on a sev

[G1sammoms]

Has anyone ever herd of someone using a elevator on a sev to help with performance issues
....????
Specifically.. to help get over or out of the hump?
Just a thought ....

Thanks

[AJW]

They shouldn't need an elevator if within weight limits and properly set up & skirt trimmed correctly. An elevator is just added weight and an extra complication that can go wrong. Some hovercraft use them to trim the craft in flight and help stop plough in, but they don't have the Sevtec skirt design.

[bphillip2]

It should add a small amount of drag and weight, not sure how it could help in any way.

[G1sammoms]

I thought it might help first pull the nose over the front of the hump and then help lift the rear ..

[bphillip2]

The only things that really affect plane out performance are thrust and weight. More weight means a deeper hole in the water to climb up out of. In a SEV the two compartment skirt does create a situation in which the front area may not be fully utilized, due to trim. Moving weight forward solves this, during plane out. A trim wing will produce very low forces to pitch the nose down, and at the cost of thrust. Moving your seat forward 2 inches would be far move effective.

[beezer]

been there, done that.... then took it off. waste of time and money (and weight). I'm a pilot, certified aircraft mechanic, aircraft builder, etc.... turns out it's far easier and more effective to just shift weight in the hull. get to know your craft, and don't be afraid to move people to obtain balance. I tell every new passenger to follow my hand signals or position. try different configurations of 1,2,3 people & do what it takes to give neutral CG. 2 on board, the front pax may need to be 18" aft of the pilot's chair.... so be it. 3 on board the 3rd may need to be center and near the back, wit right pax forward, etc, anyway, once you know your basic balance you can load up & be close enough so that sliding your chair an inch or two will trim

[John Robertson]

You shouldn't need to shift stuff around as the dual compartment cushion automatically stabilises the craft in pitch. Roll stability is controlled by the low-pressure bag skirt - it's possible to operate the craft with up to 5 degrees of fixed roll with little or no performance issues. Passengers should be able to move around freely without causing any significant issues.

If your craft doesn't do any of the above then you've got issues with skirt trim or the lift system.

[beezer]

I agree that if it won't plane out the problem almost always with the skirt. the drive can be at fault too, but the ratios are pretty well figured out these days & if the plans were followed it's probably not that. I've only built 3 Sevs, all were (are) sensitive to cg.... yes you can drive them out of balance but it's easier when the cg cg is considered when loading the craft. the Scout I built has the pilot station on center and I can turn by simply leaning my body, same as a hard floor inflatable with an outboard motor I had once. My 16' Surveyor I have to load slightly aft to trim neutral. this is it's 12th season.... on it's second skirt, around 400 hours on all kinds of water.

back to the original question.... trim tab. not worth the effort. check the skirt trim first