Undecided, Surveyor, Prospector or Geoduck.

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eccles
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Joined: February 13th, 2012, 5:52 am

Undecided, Surveyor, Prospector or Geoduck.

Post by eccles » April 26th, 2012, 7:07 am

Hi guy's,,I currently have in my possession the following items; 1x 1.3 ltr. Suzuki, ( NOT Geo ) ALL alloy, Four cyl. engine @ 66 h.p. ( flat out!), 1 x 28", 12 blade Multi-wing fan, set at 25 degrees, 1 x 28.25" f/glass lift duct, 1 x 45" wood prop.( Don't ask for pitch! The builder of the "Beachcraft" hover over on Hovercrafter.com ,Dave Beachy, claims 300 lbs. thrust from this prop.! He sent me a template & specs. & I carved one.). 1 x 45.5" single skin f/glass thrust duct.. 1 x 13.5 h.p. near new, Briggs & S. engine. I'm starting to lean towards the Geoduck as a larger,simpler build. Could the above items be used as a twin engine version of a Geoduck? Thanks,,sitting back waiting for ridicule & disappointment...Eric ;)

dnantha
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Re: Undecided, Surveyor, Prospector or Geoduck.

Post by dnantha » April 26th, 2012, 9:56 am

Good questions Eric. I heartily support you in your efforts to select a project and to find ways to use what you have available. Sounds like a good pile of stuff. This site deals with technical stuff about our kinds of SEVs and sometimes engineering data comes through as terse and confrontive buts thats just how these typed messages are. they dont show the gentle human side of the person giving the technical help.. Also sometimes when I get a great Idea like flying hovercfaft submarines powered by dirt. The technical realities sort of hurt my feelings when Im presented with them by others with more experience. (dont taze me again bro') Keep it up though. Your Ideas sound a hell of a lot better than mine. Its just this spirit of ingenuity that you have that brings new ideas and life into our hobby/vocation...I havent a clue whether any of your stuff will work,,,but Im proud of ya anyway. Welcome aboard....Dan out

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bphillip2
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Re: Undecided, Surveyor, Prospector or Geoduck.

Post by bphillip2 » April 26th, 2012, 11:02 am

The geoduck is a great craft with that 1.3l engine, no second engine needed. Sell the Briggs on ebay. Dan went for a ride on one with that motor. I would would have to check on drive ratios for that lift fan, stock is 9 blades. The prop and duct might work, just expect a reduction in performance because of the small diameter. The duct would need to be about 54" to maintain the same level of performance. What does this duct look like?

A word of caution though, the duct may be worse than nothing depending on whether it was made properly.

300 lbs of thrust? With what hp? That does not speak to the efficiency of the setup. Some airboats have 1450lbs of thrust! The stump puller they call it. But they use 500 hp to do it. So they get 2.9 lbs of thrust per hp. The surveyor gets about 9 lbs of thrust per hp. Wow I'm going to rich! I invented a prop that is 300% more efficient! Oh wait, the Wright brothers knew this some time ago, the airboat folks just invented a prop setup that is 300% LESS efficient :(

So to make a craft that is pleasant own and operate like the SEV is designed to be we need to keep thing light and efficient.

eccles
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Re: Undecided, Surveyor, Prospector or Geoduck.

Post by eccles » April 27th, 2012, 6:35 am

Thanks Brian,, the thrust prop. ratio, on Dave Beachy's craft is, 2.867 to 1 , using a stock 3 cyl. Suzuki GEO engine. Top pulley = 12.765". Bottom pulley = 4.75". The Thrust duct has a 12" radius inlet & 12" duct (flat?? ) area....Eric

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bphillip2
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Re: Undecided, Surveyor, Prospector or Geoduck.

Post by bphillip2 » April 27th, 2012, 6:54 am

If we can establish a data point for this prop it could be integrated into the geoduck drive system.

eccles
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Re: Undecided, Surveyor, Prospector or Geoduck.

Post by eccles » April 28th, 2012, 7:10 am

I can only suggest you look at Dave's Beachcraft over on Hovercrafter.com. You don't need to be a member to view the "Builders Corner". There is also a video of him making this prop. & the thrust duct. Eric

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jchovernut
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Re: Undecided, Surveyor, Prospector or Geoduck.

Post by jchovernut » April 28th, 2012, 8:49 pm

I'm looking at that engine to use on my 18' Prospector. I've been to several auto-engined aircraft seminars at Sun-n-Fun in FL and have found the 1 & 1.3 3 & 4 cylinder Suzuki engines are very popular because of their light weight and robustness. As Bryan said, you need nothing else in the engine bay other than that Suzuki engine...don't bother with separate lift!! I think an 8x18 Geoduck would be quite a nice ride with that setup. Is it carb or fuel injected? You can boost it to just 5psi and get a massive amount of torque from it, too!

I know Dave Beachy and am familiar with his 'Beach-Crafts.' That's a 4-blade, right? I thought he built his ducts out to 54" I didn't realize they were that small at 45". I think he's been running the 3cyl Geos on his hovers and has pitched the prop to absorb the 1.0L horsepower, so that's where I'd begin in the power balance equations. If you confirm this with Dave and see what RPMs he gets at WOT, we might be able to reverse-engineer a prop curve. You can measure the pitch with a protractor out at the 2/3rds length point on the blade to get a rough guesstimate of the pitch.

The attached photo shows some numbers Jeron Smith of Raven Redrives put out for the 1 & 1.3 L engines, both normally-aspirated and turbocharged. The Turbo 1.3 puts out 115hp and 142 ft-lbs of torque. Apply the prop drive ratio to the torque and you have quite a bit on your hands! Evidently, there's a 1.5L MPFI version of this engine still being manufactured and being used in Suzuki Swifts overseas...no action here in the US, though.

The technical manual from Raven might help you with that engine:
http://www.raven-rotor.com/
Attachments
Screen shot 2012-04-28 at 11.40.46 PM.jpg
Geo/Suzuki specs
Screen shot 2012-04-28 at 11.40.46 PM.jpg (81.4 KiB) Viewed 4018 times
John Carter
SEVs: Vanguard, FanTastic, Prospector, Explorer
Others: StarCruiser, UH-18P, RX2000
http://www.hovernut.com

eccles
Posts: 31
Joined: February 13th, 2012, 5:52 am

Re: Undecided, Surveyor, Prospector or Geoduck.

Post by eccles » April 29th, 2012, 6:56 am

Doh!!!! I'll make sure to wear my glasses from now on!!!!! Of course it's a 54" thrust prop.!! As you guys say " My bad ".

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