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jim w - n/a
12-May-06, 04:25 PM
Hi All

Im new to this, and am planing to build a racing craft (wife permitting) now Ive some recent exerience with fiberglass and am well awere how easy it is to over wet the fiberglass adding excess weight, as Im a fabrication engineer and used to working with metals a aluminium craft looks a far esier build, as more controle over the weight with regards to gauge of material thickness etc. Has any one got any experience of this?



Regards



Jim

hovercad - n/a
12-May-06, 07:55 PM
Hello

Richard Evans did one.(He's the only person I know that has no doubt theres's many more.)

http://www.rhevans.co.uk

This may help.



Craig

Michel - n/a
12-May-06, 10:11 PM
Think about:

will it be easy to fix a crashed hull ?

Look at the bottom of various ones and imagine how could aluminium reacts at sliding on rocks, bumping bank, etc....

My opinion is alu is more fitted for cruising craft than racing, you have more control on risks.

May be I' m wrong.....

hovercad - n/a
12-May-06, 10:26 PM
Just playing devils advocate.

wooden craft.

Nails hammer bit of glue string.DONT have to wait hours for the thing to cure.LOl out next race.



But this is someone thats been trying for years to go racing maybe next year.

So ignore me.





http://hovercraft.org.uk/images/icons/smiley_icons/icon_biggrin.gif

jim w - n/a
14-May-06, 07:31 PM
may be Ill go for ferrocement http://hovercraft.org.uk/images/icons/smiley_icons/icon_lol.gif

I think I'll design it sectional and rivet it together so it will be quicker to repair.

richardevans - n/a
15-May-06, 08:49 AM
Speedymartin wrote:



"Think about:

will it be easy to fix a crashed hull ?"



It certainly is easy - there's no need (he says bravely).



I used a welded tubular/T-section space frame and this stood up well to quite a few crashes during my Novice races, and I have never needed to repair it. The biggest crash was when Rachael Gifford's aluminium craft ended up on top of mine. On that occasion the hull survived easily, but the duct (which was GRP) was badly damaged!



Jon Curtis built his own aluminium craft too. See the gallery on the left (this HCGB website) for some of his pictures. Mind you aluminium craft do tend to be a bit heavier than GRP.



Where abouts do you live Jim W?



Regards,



Richard E.

hovercad - n/a
15-May-06, 10:03 AM
Just thought i would mention this.



On ebay

4640066460





Not mine dont know the person.



I would but my back gardens full up with 2 hulls

4 motor bikes.

2 wind surfers

1 canoe,

and loads of rubbish.



Damn glad i dont live next door to me.





Craig

jim w - n/a
15-May-06, 08:30 PM
Had a look at the pic on ebay, looks like that would end up being quite heavy with all the frame work, my idea would not require a frame as the shape and design would form its shape,

i can see using a frame would make the build esier, but if you look at the shape its all triangles and i'd be replicating that

as a skin, thicker where required.



regards



jim



Ps Im in leeds (pudsey) west yorks

jar2 - n/a
15-May-06, 08:44 PM
Jim,



Have you looked at foam composite construction? You can make a very stiff frameless structure that would weight less than half a GRP hull.

Michel - n/a
15-May-06, 09:56 PM
Hello all,

I' ve made a bed on my minibus with carbon honeycomb boards, coming from Airbus floors, they are incredibly stiff and strong for the weight. For my twin diesel hovercraft, deck and bottom floor are made with honeycomb boards.

For my surfboards and surfskis, I use polyurethane foam and polyester resin, and more often polistyren foam with epoxy resin. But a surfbord is less than 3 kg, and a surf kayak less than 6 kg. Forces are not the same.

It' s exact that , if you replace a thin fiberglass lining by a thicker foam board, for equal weight, strength is higher.

N.B. When I wrote: " think about , will it be easy to fix a crashed hovercraft " , you should have red: are you more trained to put fiberglass on a hole caused by a big rock, or do you prefer to hammer and put rivets on the wounded part ? Personaly , I' m well trained to fiberglass and resin, and not at all to aluminium.

For aircrafts, aluminium is used for high shear stress parts , and fiberglass and resin is used for light aircrafts and gliders, when carbon and resin is used for outside wings, helicopter prop blades or light aircraft landing gear.

Both aluminium and fiberglass are used the same way depending on what is needed.

An hovercraft hull is exactly on the edge between use where alu is ideal and use where fiberglass is the right one. Make your mind, I think both are equal in results but very diferent when building craft.

If I had a hammer......

jim w - n/a
16-May-06, 07:02 AM
I've just finished building a bed for a bed race using hidensity polyurethane foam and covering it with fiberglass apart from being a time consuming operation it was not as light as i would have liked. The old bed weighed 43Kg and the new at 33Kg even though i'ts 10Kg lighter i was still surprised at only 1 layup of mat and resin how heavy it was.

jon_curtis - n/a
16-May-06, 06:05 PM
i would make a cruiser out of ally!



but i made this, and its good fun!





index.php?t=getfile&id=225&private=0



its your choice of what you like to work with! the sheetmetal factory i worked at, at the time helped a tiny bit!

Ian Brooks - n/a
16-May-06, 08:58 PM
Do the ducks still fly backwards in Pudsey???



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To keep the soot out of thier eyes!!!!!!



Ian



(Brought up in Garforth)

jim w - n/a
18-May-06, 07:32 AM
Do the ducks still fly backwards in Pudsey???



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To keep the soot out of thier eyes!!!!!!



Ian



(Brought up in Garforth)














The soot has gone, but the birds still fly backwards, old habits die hard.