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Old Oct 05, 2012, 02:43 PM
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madbugger's Avatar
Ayrshire, Scotland
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Originally Posted by Firehawk989 View Post

The weir that geofrancis posted looks like a lot of fun! Sadly we don't seem to have many features like that around here; what purpose do they serve other than fun spots to run your jet boat?
As soon as I saw that video of the auto-bailer which geofrancis found for me I realised that was the one you had been referring to.

As for weirs, I'm not sure of their original purpose, but some possible reasons could be

1) They deal with sudden changes in ground level (like locks on a canal).
2) They keep a depth of water upstream for whatever purpose, whether agriculture, industrial or even for river navigation on big rivers.
3 They trap errant fallen branches and other debris which might otherwise get into waterwheels or similar machinery. If you look carefully at my photos you may see a big branch towards the middle which will be trapped until the next spate.
4) They do a bit to regulate the flow downstream and keep it constant through drought and flood, like a dam.

I don't know about their purpose elsewhere, but in Ayrshire there used to be many woollen mills. Originally water-powered, they would have been converted to steam then diesel or electric power before they closed, but they still needed a lot of water for the processes. The last mill in my village closed in the sixties or 70's and was pulled down. I didn't live here then so I'm a bit unsure of exactly when it shut. Nothing remains, but it was close to that weir and any of the reasons I've given above could therefore explain the presence of the weir.

That said, they have come into their own now we have model jet boats. Hundreds of years without a purpose have now been ended
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Old Oct 05, 2012, 03:43 PM
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madbugger's Avatar
Ayrshire, Scotland
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Having poked about on the interweb, I find my gut feelings about the purpose of weirs were true. It appears some other uses for weirs include diverting some river water into a canal, stopping seawater tides from backing up into freshwater estuaries and finally as part of schemes to measure flow rates. None of these uses apply to our local ones so I think my last post solves it for these.

All pales into insignificance compared with their use for jet boats, of course.
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Old Oct 07, 2012, 09:30 PM
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Prototyping a fast patrol boat thing ( part 3 )

Just found a gunner and small military items to use..

Cut out some boat bumpers (tire look alikes) and now i must find a way to paint them, so thats coming next..

Underway form china are some small car led lights to put on top for the search light and a keychain camera and more but thats not for the boats.

Almost forgot, finishing up the metal prop install..
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Last edited by RimRc; Oct 07, 2012 at 09:38 PM.
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Old Oct 08, 2012, 01:38 AM
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South Africa, GP, Alberton
Joined Sep 2012
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testing after the prop mod . it now takes a 38x25x4 prop that i ground down to 19mm. check it out !

tear into 2s 3s testing in small pond (2 min 26 sec)
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Old Oct 08, 2012, 01:59 AM
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Ayrshire, Scotland
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Originally Posted by RimRc View Post
Just found a gunner and small military items to use..
Almost forgot, finishing up the metal prop install..
With more weight high up I'll guess it might not be as stable as your other boat, although that may not be as much of a problem for you since most of your boating is done on the sea rather than rock-filled streams. Either way, it's beginning to look awesome

Give us more details on the metal prop installation, please?
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Old Oct 08, 2012, 08:08 AM
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Originally Posted by madbugger View Post
With more weight high up I'll guess it might not be as stable as your other boat, although that may not be as much of a problem for you since most of your boating is done on the sea rather than rock-filled streams. Either way, it's beginning to look awesome

Give us more details on the metal prop installation, please?

Racing can still be done, the guns are for other boats that are about to win the race..
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Old Oct 08, 2012, 02:15 PM
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Washington State
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Originally Posted by RimRc View Post
Racing can still be done, the guns are for other boats that are about to win the race..


That's funny! Love it!

Your boat is really looking good. It's fun to be different.

Reading with interest these posts about metal props.
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Old Oct 09, 2012, 12:02 AM
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Originally Posted by 7car7 View Post


That's funny! Love it!

Your boat is really looking good. It's fun to be different.

Reading with interest these posts about metal props.

Its not that easy to dremel it to shape.
Another thing is when the shaft and prop is not in balance,
it can damage the drive itselve. Thats what got me from finishing it now.

What i used was a hk 435 prop ( HK-5B11X35 ) but thats for a 4mm shaft,
to fit it to the 3mm shaft i used heatshrink tube, but it is still not a good fit.

later this week i will post some better pics when i get to work on it again..
but finishing it is goning to take a while, because this prop damaged my stator.
so i need to make a new stator first.
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Old Oct 09, 2012, 11:14 AM
Fix it till its broke!
United Kingdom, Scotland, North Ayrshire
Joined Feb 2010
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Originally Posted by madbugger View Post
That must be the technique Firehawk989 was telling me about. Thanks for finding the vid - makes it all much clearer. Like you I'd want it to right faster - with rivers flowing as fast as some of ours, it would otherwise be in the next county before it had recovered on to an even keel

Where can you get the Graupner minijet at present. About 5 pages back, in my post #449, I mentioned I was using their 3mm shaft and impeller (sourced from Cornwall Models) but when looking up C.M.B's. url to put it in my post, I noticed that they although they still have the spares, they still don't seem to have the complete drive in stock. It's not even available from Graupner themselves in Germany at the moment. I'm sure it must be made somewhere in the Far East anyway. I had thought about making my own reverse bucket but hoped the genuine thing would be back on the shelves first, in case I made a pig's ear of my home brewed version and needed a replacement.

The Garnock weir looks just a bit more manageable than mine. Maybe I'll try that first as a rehearsal if I decide to take on my local one. Easier to retrieve the boat in Kilwinning than on my raging torrent, if it all goes horribly 'Pete Tong'.
just make sure its not been raining for a few days before you try it...that might be hard now the weather has changed or it will be too fast to use.

https://maps.google.co.uk/?ll=55.645...00284&t=h&z=19

there is a big pool behind it. i was going to get my friend in a canoe to wait there incase something went wrong with the self right at least the first couple of times.

if you look further downstream the river is at its shallowest and upstream has a lot of barriers. i might take a cycle along there soon to see if any of it is useful.

and i got my new water jacket!

i ran it full power in the bath for 1 min and the motor was still cold but the battery and esc heat up slightly but i doubt i will ever have use full throttle for that amount of time.

the ride plate that sticks out the back looks very interesting i might knock something together using some thin metal or plastic sheet.
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Last edited by geofrancis; Oct 09, 2012 at 11:47 AM.
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Old Oct 09, 2012, 03:09 PM
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Ayrshire, Scotland
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Originally Posted by geofrancis View Post
the ride plate that sticks out the back looks very interesting i might knock something together using some thin metal or plastic sheet.
Yea, the ride plate is worth doing. Stops rocks and gravel damaging all the delicate parts hanging out the back (sorry, that should be 'off the transom' ) and if you get it right it can also keep the drive from cavitating as much. It also keeps the hull more level, thus reducing porpoising which is why I suggested it to Jan.

I guess you could use plastic although it would have to be rigid. I used a left over offcut from a sheet of K&S alu (from the model shop) 'cause it was to hand, but any alu, dural or stainless would do if it's rigid and not too thick.
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Old Oct 09, 2012, 06:04 PM
Fix it till its broke!
United Kingdom, Scotland, North Ayrshire
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Quote:
Originally Posted by madbugger View Post
Yea, the ride plate is worth doing. Stops rocks and gravel damaging all the delicate parts hanging out the back (sorry, that should be 'off the transom' ) and if you get it right it can also keep the drive from cavitating as much. It also keeps the hull more level, thus reducing porpoising which is why I suggested it to Jan.

I guess you could use plastic although it would have to be rigid. I used a left over offcut from a sheet of K&S alu (from the model shop) 'cause it was to hand, but any alu, dural or stainless would do if it's rigid and not too thick.
i was thinking something like credit card plastic.... come to think of it i have a subway bonus card thats about right.

has anyone done any reinforcing of the hull? i have already put a 2 inch crack down the bottom of my hull. i was thinking thin carbon fibre strips or something epoxied to the inside of the hull.

so new list of things to do...

autobailer
ride plate or trim tabs with gyro assist.
reverse bucket
gyro
lights
moving heads
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Last edited by geofrancis; Oct 09, 2012 at 06:31 PM.
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Old Oct 10, 2012, 08:21 AM
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Originally Posted by geofrancis View Post
i was thinking something like credit card plastic.... come to think of it i have a subway bonus card thats about right.

has anyone done any reinforcing of the hull? i have already put a 2 inch crack down the bottom of my hull. i was thinking thin carbon fibre strips or something epoxied to the inside of the hull.

so new list of things to do...

autobailer
ride plate or trim tabs with gyro assist.
reverse bucket
gyro
lights
moving heads
I was thinking of using some sound-deadening matt from the car audio world to re-enforce the hull of my boat. The matt is thin and self adhesive, they use it on the metal of cars to prevent it from flexing and vibrating. It turns a thin sheet of metal into something much more rigid. I figured it would do the same to the boat. Its waterproof too, usually made of rubber and some sort of asphalt based adhesive. its not all that heavy either, and one layer would probably be more than enough...
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Old Oct 10, 2012, 09:08 AM
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United States, MI, Royal Oak
Joined Nov 2005
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Nebey, do you have a link to the material that you're referring to?
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Old Oct 10, 2012, 09:20 AM
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Originally Posted by JGuilty13 View Post
Nebey, do you have a link to the material that you're referring to?
dynamat

http://www.amazon.com/Dynamat-19100-...ywords=dynamat

fatmat

http://www.amazon.com/FatMat-mill-Bu...eywords=fatmat

Roadkill

http://www.amazon.com/Stinger-Roadki...words=roadkill

Boom Matt

http://www.amazon.com/DEI-050220-Boo...words=boom+mat

http://www.amazon.com/050200-Boom-So...words=boom+mat

You only need a piece to fit inside your boat... so the fatmat and some of the other ones are much more than you need. The dynamat license plate kit would probably do your entire boat, for $10. Same with the boom matt kit at the bottom. I am skeptical about the spray in stuff, but I posted it here if you are interested...

Follow instructions carefully, you may need to scuff up the the surface you apply it too, and do it in a warm place... this stuff is easier to work if its warm.
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Old Oct 10, 2012, 11:00 AM
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Washington State
Joined Oct 2007
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Quote:
Originally Posted by RimRc View Post
Ii used heatshrink tube, but it is still not a good fit. .
Might want to try some selections of aluminum or brass or copper tubing from a hobby store or hardware store if you have one near by.
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