Lift fan

highlandhovercraft
Posts: 152
Joined: February 14th, 2012, 3:51 am

Re: Lift fan

Post by highlandhovercraft »

How heavy is the scout? Weight on a small craft will play a big part with performance.

I went from 6 blades to 9 on my surveyor as I was having lift problems. " waste of time & money"! I reverted back to 6 in the end after lots of messing around trying to get the craft to operate any sence. You will end up with too much lift if you keep the pitch at 25*, so the air flap doesn't work like it should at higher rpm. Your thrust will be reduced as more power is needed to spin the lift fan. My advice stay with 6 blades and sort out the real issue.

As mentioned, check fan tip clearance.

Look at the plans again and check where the splitter bar should be and put it there or if someone on here has a working scout copy their splitter position.

Check your skirt. This was the problem I had with the surveyor :oops: Originally I trimmed the surveyor skirt by adding ballast to the pilots position and tethered the craft down. I ran the craft at around 2500rpm and used a pre measured stick under the bow to determine the hover height. This method works if you are sure that your rear skirt is correct. Best way is to not cut corners and put the craft on pre set blocks of the correct hover height. I found my rear skirt was banana shaped :oops: :shock: , so when the craft was on hover the rear end was sitting low, so front trim was also wrong when I was using the stick under the bow method. Put the craft up on blocks, mark the perimeter of the craft on the floor with chalk. The ground contact line of the skirt should line up with the chalk line, when the craft is not running. if it doesn't the craft will never operate any sence.
bandit1538
Posts: 162
Joined: February 15th, 2012, 9:52 pm
Location: Skamokawa Wa.

Re: Lift fan

Post by bandit1538 »

highlandhovercraft wrote:How heavy is the scout? Weight on a small craft will play a big part with performance.

I am heavier than it should be but didn't have a scales to weigh it, when it was just bare hull before skids, wiring, skirt, & steering controls my guess is around 150lbs or under, my wife & I was able move it easy in this condition and I have a bad back.

I went from 6 blades to 9 on my surveyor as I was having lift problems. " waste of time & money"! I reverted back to 6 in the end after lots of messing around trying to get the craft to operate any sence. You will end up with too much lift if you keep the pitch at 25*, so the air flap doesn't work like it should at higher rpm. Your thrust will be reduced as more power is needed to spin the lift fan. My advice stay with 6 blades and sort out the real issue.

As mentioned, check fan tip clearance.

Tip clearance is less that 1/4"

Look at the plans again and check where the splitter bar should be and put it there or if someone on here has a working scout copy their splitter position.

Did that

Check your skirt. This was the problem I had with the surveyor :oops: Originally I trimmed the surveyor skirt by adding ballast to the pilots position and tethered the craft down. I ran the craft at around 2500rpm and used a pre measured stick under the bow to determine the hover height. This method works if you are sure that your rear skirt is correct.

Best way is to not cut corners and put the craft on pre set blocks of the correct hover height.

I used the blocks from the first trim that another guy did for me and found the Bow & Partition skirts were too long so I re-trimed them to 1/4" clearance.

I found my rear skirt was banana shaped :oops: :shock: , so when the craft was on hover the rear end was sitting low, so front trim was also wrong when I was using the stick under the bow method. Put the craft up on blocks, mark the perimeter of the craft on the floor with chalk. The ground contact line of the skirt should line up with the chalk line, when the craft is not running. if it doesn't the craft will never operate any sence.
The craft works fine in water, it's short grass opperations that I'm having problems with.
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: Lift fan

Post by bphillip2 »

A pair of bathroom scales will weigh a Scout. You don't have one? What about your neighbor?
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