nosedive

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pmovermyer
Posts: 3
Joined: May 2nd, 2012, 7:47 am

nosedive

Post by pmovermyer »

I built a 22 foot explore
when she lives the front lifts off the ground first as expected and because its lighter is always the last to settle. However between 30 and 40 miles an hour the nose digs into the water. Quickly bringing the craft almost to a stop.

The only way I've been able to prevent this is to move after 15 to 20 miles per hour all the wait ( people ) to the rear.

I do you have the divider skirt. I was thinking abot cutting it shorter so I could not contact the water also that would provide better air flow side to side?
Maybe I should increase the size of holes from the airbags?
highlandhovercraft
Posts: 152
Joined: February 14th, 2012, 3:51 am

Re: nosedive

Post by highlandhovercraft »

I had a similar thing happen on my surveyor. It turned out to be incorrect skirt trim. Check your skirt trim and centre of gravity
bandit1538
Posts: 162
Joined: February 15th, 2012, 9:52 pm
Location: Skamokawa Wa.

Re: nosedive

Post by bandit1538 »

Also check to see if you still have your partition skirt, I lost mine on the Scout and had the same problem.
If it aint broke, don't fix it.
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bphillip2
Posts: 430
Joined: February 2nd, 2012, 10:29 pm
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Re: nosedive

Post by bphillip2 »

This is either incorrect bow skirt trim, partition trim or both. What trimming procedure did you follow?
pmovermyer
Posts: 3
Joined: May 2nd, 2012, 7:47 am

Re: nosedive

Post by pmovermyer »

I propped the hovercraft at 18 inches. And cut to meet the ground.
is there a better procedure? The front skirt hovers out about a half inch

When standing still. I have not checked the back skirt in hover.
dbhyslop
Posts: 66
Joined: February 14th, 2012, 9:59 pm

Re: nosedive

Post by dbhyslop »

Your partition skirt may be a touch too long, reducing airflow into the bow skirt. I think all of Barry's material specify both the bow and partition skirt should be cut to the ground contact plane, but it seems like a lot builders now are trimming the partition just a little higher.
pmovermyer
Posts: 3
Joined: May 2nd, 2012, 7:47 am

Re: nosedive

Post by pmovermyer »

Thanks everybody I know what I'm doing this weekend
bandit1538
Posts: 162
Joined: February 15th, 2012, 9:52 pm
Location: Skamokawa Wa.

Re: nosedive

Post by bandit1538 »

dbhyslop wrote:Your partition skirt may be a touch too long, reducing airflow into the bow skirt. I think all of Barry's material specify both the bow and partition skirt should be cut to the ground contact plane, but it seems like a lot builders now are trimming the partition just a little higher.
Barry told me to cut for 1/4" clearance while on the blocks.
Pat
If it aint broke, don't fix it.
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bphillip2
Posts: 430
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Re: nosedive

Post by bphillip2 »

Paul, which videos do you have?

18 inches is wrong, where did you get that number? The hover height is (11*12)/8=16.5" if your craft is 11 feet wide.

1/4" would be for a Scout, this Explorer should have the partition at least 5/8-3/4 off the ground on the first trim.

Be sure to have safety blocks underneath while trimming, or you might get flattened.
highlandhovercraft
Posts: 152
Joined: February 14th, 2012, 3:51 am

Re: nosedive

Post by highlandhovercraft »

For my surveyor I made up a set of wood blocks the correct hover height and bolted then to the skids. I was then able to check how the skirt sat all the way around the craft when under power. If I had trimmed my skirt that way the first time I would have noticed the rear skirt was wrong which led me to trim the front skirt wrong :oops: While blocked at the correct hover height the ground contact line of the skirt can also be checked and adjusted. It is definetely worth making up a set of trimming feet which are there for future use when you replace the skirt.
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