Topic: any one out there interested in airboats, or am I the only one building them (Read 9534 times)

d-jnana · « **on:** November 18, 2006, 03:28:14 pm »

Hi, I design/build and run airboats. They are fast, furious, and handle extremely sharply. They are the greatest fun model boat there is, but there seem to be no British websites dedicated to them. All the sites I have found are in the US or Canada. I,m not alone in the UK am I.
If any body out there is interested (especially in S.Wales) give us a shout. I'd be interested to share info, and plans.

Glyn Cleaver · « **Reply #1 on:** November 18, 2006, 03:38:50 pm »

Hi There, where are you in South Wales? If you are near Barry, pop down to Cold Knap lake on a Sunday morning. You will find lots of different boats down there and if you bring your model with you, then people may give it a try. The lake is busy from 10:30hrs onwards. I may see you there, please say hello if you come down.
Cheers Glyn

OneBladeMissing · « **Reply #2 on:** November 18, 2006, 05:25:54 pm »

As far as the MPBA is concerned, I believe the only airscrew driven boats allowed (officially) in the UK are 2.5cc tethered hydros. I can recall reading that rule in the rulebook, however that was some years ago.
I think there could be a problem if the prop is accessible to fingers etc. Health & safety and all that stuff!

andywright · « **Reply #3 on:** November 18, 2006, 05:26:28 pm »

I had the same trouble with RC landyachts, quite a following in the states and on the continent, I imported 6 from the states and sold them all, but they all were spread out all over the country. I have since built a couple because they are good fun.

J.beazley · « **Reply #4 on:** November 18, 2006, 06:57:20 pm »

world wide site for some people with airboats is rc-hovercrafts.com

im a member of this site and its not all hovercraft there is a fair few members who have airboats aswell.

on the other hand i dont think there is much interest in them here in the UK as we dont have much swamp land unlike the states and on the continent.

Jay

Welsh_Druid · « **Reply #5 on:** November 18, 2006, 08:15:28 pm »

You will have to come to North Wales to see this one. Built it a few years ago - hull is just a slab of foam covered in balsa but styrene sheet underneath for when it runs up the slipway. Powered by an seven cell nimh pack with a 500 motor on an MFA Olympus gearbox - it goes very well.

Don B

d-jnana · « **Reply #6 on:** November 18, 2006, 11:31:07 pm »

To Glynn, I'm in Swansea, not to far from Barry. One question though; does Cold Knap lake permit the dreaded ic? I like mine noisey and smelly. Well actually mine are noisey and smelly.

To one blade missing. The HSE all need stringing up by thier squashy bits, they seem to think we are all morons incapable of logical thought. My air boats have a guard ring around the prop, and the prop painted bright red, I also (as I expect you do ) engage brain before starting any potential dangerous activity. I'd still like to know more about the tethered thing, though it seems a shame to tie up a very manouverable craft.

To andywright. Yeah also a bit off beat, I built one from the free plans in MMI a few years back. It as a great little thing and always attracts a lot of attention along the bike path along the Swansea sea front. Hows this for an idea. A land airboat. I'll post a pic of the one I have iin progress at the moment. It has an animal of a Veco 19 driving it.

To J. Beazley. I'll check this out . Cheers mate.

To Welsh_Druid. Looks great. My current one (as previously stated) is ic. It has a Chinese made XY52 on it, spinning an 11X9. The prop is probably a bit large,and I am thinking of cutting the diameter and increasing the pitch. I have been told that this engine with an 8X12 will rev to somthing like 28 000 to 32 000 rpm, and pull a WOT4 (small training airplane) to somthing close to 80mph in level flight. I suspect that that sort of performance is unlikly on water due to the drag. But here's an idea for any air boaters to try. Put an intake duct behind the prop, feed the pressurised air to the front of the boats underside where it's first contact with the water is. At this point fit a "spray bar" to let a stream of bubbles "lubricate the bottom of the hull over the water?????????? Or how about a stepped flat bottom????????? Or how about combinning the two?????????? Or am I getting into the realms of? Sci Fi.
Perhaps somebody out there may ahve even tried these things. let me know if you have. It could save me a lot of time and cash. Cash that my wife just wouldn't understand as being essential in the pusuit of marine knowledge advancement.

Just a quick p.s.
sorry for the typos. 3/4 of the way through can number 4 and getting a bit................ confused.

tobyker · « **Reply #7 on:** November 18, 2006, 11:57:23 pm »

I built one for my Welsh holiday, using the smallest cheapest brushless bell motor and ESC from All Electric R/C . It won't go at all on land but does go fast on water. I got some ideas from Florida airboat club/magazines websites. The boats come in all shapes and sizes from 12-seater tourist boats to single-seater stepped racers - with videos of the latter performing. My lad took great video of mine. I shall have to see if I can put it up on a webpage somewhere. Theyare great fun but you have to get the hull design right or they won't turn very well on air rudders - and water rudders are cheating!

d-jnana · « **Reply #8 on:** November 19, 2006, 10:31:27 am »

cheers tobyker, would appreciate seeing the vid. I will have to post some pics of my current boat.
But in the meantime here is a description if anyones interstd.
the whole thing is made from marine grade birch ply. the sides deck and framing are 4mm and the bottom skin is 2.5mm with grp skin on top of that. Pylons from the same 6mm as is the rudder. The tank fairing in front of the pylon is vac formed styrene. The prop guard ring is laminated from three layers of 2.5mm birch ply epoxied round a former. the hull form resembles a punt with slopped sides and flat upright transom, and curved up front. It all sounds a bit heavy and it is, but it is designed to withstand the knocks of running on shallow water and weed, or even snow and ice. It goes like the proverbal off a chromed shovel, and turns 180, literrally, in twice its length, at full throttle. the huge rudder helps a great deal though.

If

OneBladeMissing · « **Reply #9 on:** November 19, 2006, 06:01:15 pm »

d-jnana, I'm sure most of us know that H&S are a pain, and that most of us always take suitable precautions when using models with whirring props, power tools, cars, etc. But H&S have to consider the lowest common denominator, i.e. the s**t-for-brains types who, if anything can happen to them, will! We also need to keep a wary eye on our increasingly litigious society, and cover our backs accordingly.
2.5cc airscrew tethered hydros are the only permitted airscrew driven craft in legal competitions, and are a bit fast! I don't know if there are many running them in this country, but I've seen some running at the Naviga championships and they are very impressive. Needless to say, those who operate them know what they're doing.

d-jnana · « **Reply #10 on:** November 19, 2006, 08:26:30 pm »

Hi one blade missing. You are of course right about the lowest common denominator, I know all about them, I'm a teacher of design and technology.
We have the ridiculous situation which says we must teach modern techniques and processes as used in industry. They then have to produce a product for their GCSE, usually wood based, in a workshop. Now here's the rub. They are not allowed to use power tools until they are 16 or over, and strictly speaking that includes a cordless drill, or orbital sander. Now don't get me wrong, I'm all for the use of hand tools and traditional methods, in their place, but what about industry. The kid leaves school, and gets a job in a wood shop, and he/she's never even picked up a jigsaw, let alone a router, or power plane. Scary!
The same could be said of models, though despite all I have said above, I would hesitate in letting my 12 year old too near my running airboat. Let alone allow him try to start it or adjust the mixture etc. Double standards perhaps? But there were kids at a private school I used to teach at who I would allow to use the bandsaw, linisher, and so on. By the same token there were others in the same school I would hesitate to allow into the workshop. It all comes down to the individual, and the judgement of a responsible person. It is that judgement that this "nanny" state is removing and TRYING to replace with legislation, and all because of the litigious blame culture we seem to have imported from across the pond. Has no one got the courage to take a calculated risk any more. The scouts are not even allowed to play British bulldog any more!

But back to the important issues in life. Airboats. I am assuming these tethered airboats follow the general three point arrangement of most other tethered hydros. what I am wondering though is; how does the torque reaction of a large spinning prop, and the top heavy nature of an airboat with its engine in the air affect the stability. Or is it bridled in such a way as to prevent it from falling over?

d-jnana · « **Reply #11 on:** November 19, 2006, 08:48:17 pm »

A pic of my current airboat. (attached)
and my "land airboat.........Thing" the Thing has micro scooter wheels with LEDs in that flash as they rotate (attached)

OneBladeMissing · « **Reply #12 on:** November 20, 2006, 05:50:16 pm »

The airscrew hydros I've seen had a tubular "hull" with forward sponsons. The engine was on a demountable "pod" on top of the hull. I don't know if they were bridled in such a way as to prevent the hydro from tipping. There may be more info on them on the MPBA website, tethered hydroplane section, and info on speeds attainable in the records section.

Martin (Admin) · « **Reply #13 on:** November 20, 2006, 09:32:41 pm »

I've had two, well three, Extremely Exhilarating...... mad!

d-jnana · « **Reply #14 on:** November 21, 2006, 07:03:33 pm »

Hi mayhem-forum admin. Its great to know i'm not the only one who likes these swamp boats.

The idea of a tethered hydro interests me greatly. I am going to have to a bit of research I think. The feature of a removeable engine pod sounds good to me. The engine pylon on mine s only held on by two screws with the idea being that when I get round to building another hull (probavbly with a very shallow "V" leading out to a flat at the transom) I can just change the pylon over thus saving the expense of having to buy another mill. It also means that I do not have to build another rudder etc.

flag-d · « **Reply #15 on:** November 25, 2006, 06:45:05 pm »

Far too long ago to remember fully, I built a catamaran air-screw driven, er, thing! Two shaped balsa blocks for the hulls joined by a 1/8th ply strip front and rear. I seem to remember a Meccano pylon an a little diesel engine on top. It was a complete nightmare to start, but once running went like a banshee. Absolutely no control what so ever. First time out on a lake it shot along really well. Mine and my Dad's idea was that when it ran up the grassy bank it would stop...it didn't! Finally it did when it hit a tree, but I had to run after it for a good few hundred yards! Built an all Meccano land-yacht type of affair for it also. Ran that tethered in our cul-de-sac: took a while to get going but was a blur once it was! Used to stop it with a broom handle when a car appeared!

Happy days

Mike

d-jnana · « **Reply #16 on:** November 25, 2006, 09:45:13 pm »

Mike your a nutter, in the best posible sense. It's guy's like you building off beat and experimental (with the emphasis on the MENTAL) craft that will bring younger and more driving people into the hobby. That is not ment with any disrespect to the older and more sedate modlers. I have also built sailing craft, and a couple of electric tugs and have a steamer on the go, as well as the high speed smelly noisey politically incorrect boats/machines. As to age perhaps you guys are wondering at my age since I am going on about younger and more driving people. Well I was born in the year England last won the football world cup. (look it up). I still feel the same mentally as I did when I was 18. I still have the same drive, and ambitions, excepting those already acheived (though I have not yet climbed Everest). Perhaps that is because I am a teacher, or perhaps because I have kids of my own, or perhaps I just refuse to grow up.
Anyway the airboat thing is at the moment what is exciting me. I can't wait for some snow, aparrently they go even faster on frosted snow than on water. Any one got any experience of that? Got any pics or vids?
Cheers for now folks off to make some Ovaltine before bedtime!

biggles1 · « **Reply #17 on:** November 26, 2006, 10:09:31 pm »

Hi If we are going to get all nastalgic can i join in .We used to run air boats at the Prince 0f Wales pond on Blackheath S London in the early 60s They were all free running could not afford radio.There were a few kits Mercury did one if i remember i had one with a mills .75 on board (i still have a mills fitted in a vic smeed Tomboy free flight plane ) how no one was seriously hurt i dont no as the pond had slopping sides when hit converted them to a real AIRboat . All our conventional boats were also free running, just set the rudder to a circle and hope for the best I had a crash tender with a E.D Racer on board i also owned a Taplin Twin (2x E.D. RACER cyl. heads) wish i still had it now. Does anyone remember the Veron Skidboat I fitted my Mills in mine great fun.The pond is still in use today i believe the Blackheath club use it for straight running.Can anyone let me know not living in area now moved to Peterborough Sorry gone off the thread a bit Dave

Martin (Admin) · « **Reply #18 on:** November 27, 2006, 03:41:30 pm »

Is it me or do airboats of the same engine size go faster than a water screw equivalent?!?!

Anyway I once ran my blue airboat ( below ) also went like a bat out of hell !
On one blowy day, it hit a slight wave, shot up in the air, did a complete backwards somersalt and landed back on the water and kept going!

Air rudders steer your airboats a bit like hovercraft, theoretical rudders if you like!
Water rudders are a lot better but sort of defeat the whole idea of an airboat!.

Martin.

d-jnana · « **Reply #19 on:** November 27, 2006, 04:26:55 pm »

Ithink your right about the speed thing Martin. As to the rudder thing, I've never actually found that, but then you've seen the size of the rudders I have fitted to mine. And before anybody asks: No ther are no sneaky water rudders out of shot.
Martin have you had a look at the cajun airboats site? there is a vid in there of an airboat at speed (it says 70mph!) which hits a ripple in a turn dose a complete barrel role aquaplaning on its prop guard and continuing without missing a beat or losing any noticable forward momentum, just a cloud of spray. I'll try to find a link later.

tobyker · « **Reply #20 on:** November 28, 2006, 01:59:42 pm »

It is very interesting how airboats steer. The rudders are fitted high up, with the wider portion at the top. When you put helm on, the boat heels, digging the forward chine in (Unlike a hovercraft). If you've got the shape aft right, the stern will skid round, and off you go on the new heading. They can turn in their own length at very high speed. Hovercraft have no grip on the water and just yaw, until eventually they take up the new heading. I once tried to see if "steam" would give way to sail in the solent. "Steam" merely carried on at undiminished speed, but aiming its quarter at us instead of the bow. We ran away, because the last thing a hover ferry does is chop the power with paying passengers on board.

d-jnana · « **Reply #21 on:** November 29, 2006, 07:28:34 pm »

Hi TOBYKER. Remind me not to come sailing with you. Mind you I have often wondered about trying that with one of the tankers you see up and down the Bristol Channel. The thought of what a tanker MIGHT do to a mirror dinghy puts me off a bit.

perkasa · « **Reply #22 on:** December 01, 2006, 11:43:28 pm »

HI,

I would love to build an air boat and would like the plans to be able to do so. Can anyone advise?

Having said that I build large model hovercraft. As a member of the Model Hovercraft Association I have insurance with them.

I raise this point as I cannot use my hovercraft at certain clubs ponds because of insurance and noise regulations. This is mainly in the New Forrest. Our club, Waterside Model Club, also within the same area does not have these restrictions. Why? Because we are a model club and cater for all, not are not just a boat club. We have Boats, Hovercraft, Cars and Helicopters.

The main problem it the fact that air boats, like hovercraft have an external propeller. This is what no one can accept and keep quoting insurance regulations. This is the easy way out because no one will ask about it , just In-case premiums will go up.

Air boats are still part of our hobby and should be accepted as just that.

In the right hands they are no more a problem than fast electrics or high speed launches or even hovercraft. Having said that perhaps scale models should not be on the pond at the same time as specialist craft. I know from experience owing to an idiot with a fast electric wrecking my scale boat that this could be part of the problem..

Does anyone else experience a similar problem just because of insurance or because other members cannot accept them??

PB

d-jnana · « **Reply #23 on:** December 02, 2006, 01:44:00 pm »

hi Martin, still can't find that link.

d-jnana · « **Reply #24 on:** December 02, 2006, 02:19:07 pm »

Firstly Peter I have sent a reply to your e-mail on my ntlworld account.
As to the risk factors, (Bl**dy HSE again). Hovercraft, and airboats are not the only vehicles with unguarded props. You mentioned helicopters, and what about aircraft. Both relatively heavy airborne (guided?) missiles. Does anyone have trouble getting insurance for them? No because there is a body licencing the operation of model aircraft. That said though I don't think membership is a legal requirement to fly, but all reputable clubs do insist on membership and have training courses.
Do we as boaters want to go down that route?
It could actually save us money in terms of insurance premiums. I raise as examples here the GNAS (grand national archery society) and the BCRA (British cave research association). Both of these bodies govern their respective sports and offer insurance (for the sum of around £45) up to 2 million or so in the event of a third party claim. I can imagine that an ill aimed arrow could do serious damage. just as an ill guided airboat could.
I'll leave you guys to ponder that.
As to the mix of high speed and scale, I believe at Bryn Bach ponds it is a case of scale on Saturdays, and I.C. on Sundays. I'm sure someone out there will correct me if I'm wrong.

Lastly if you want a set of plans for an airboat , I have drawings for all my previous airboats, and can modify and draw up any others you may want for the cost of copying them and postage. I can design to any level of difficulty in build in any material specified if anyone is interested give me a ring (01792 429235 or 07960 144514) and ask for Gary.

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Author Topic: any one out there interested in airboats, or am I the only one building them (Read 9534 times)

Glyn Cleaver

flag-d

perkasa