Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: gwa84 on February 03, 2009, 03:14:49 pm
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i use to run electric rc speed boats a long long time ago these where just cheep kits that really didn't go very fast
i have decided to build my own rc nitro boat using a 12 rc air cooled car power plant scavenged from a wrecked rc 4weel of roader i had
I've got myself a prop shaft and universal joint to fit the motor and ime working on a water cooling coil to help with cooling the cylinder
but my main problem is what prop to use any tips on what to get I'm uk based so ebay is my friend at the moment for parts
hope you can help
gwa84
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hi gwa84.
there are lots of people on this forum that will be able to help you,
i haven't got much experience from past power boats but i have had a crack at building a fast electric model. Personally i wouldn't use ebay to buy the parts unless your absolutely sure about what your buying. i would have a look at some of the products at
http://www.astecmodels.co.uk/catalog/index.php?cPath=25&osCsid=4612e92c1b39da36c9a2251d712a1741
and if you get stuck you can always contact them.
Ps what sort of model is it, hydroplane, Deep V hull etc.....
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Hi There. I am making a Zclass 12 size engine boat. I am going to try out a 35mm prop on it. I am useing a sumerged drive system. Props can be got from the Prop shop which are on the web.
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hi thanks for replying another set of bookmarks to brouse over lol
ill try a 35 mm prop the one that came with the prop shaft kit has a 55 mil prop mesured from tip to tip so i asume way way to big lol
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eny body have an idea of where to get a good v hull from ideally ime doing this on the cheep hence using what i can salvage
ille upload photos of the motor and prop shaft so you can c what ime talking about when i can fined my digi cam
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again the wesite i gave above has a few deep V hulls :-))
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had a look on the web site couldn't fined eny suitable well their say suitable for fast electric spotted this do you think it would be eny good i like the shape and should be the right size for my needs
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=220355050448
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had a look on the web site couldn't fined eny suitable well their say suitable for fast electric spotted this do you think it would be eny good i like the shape and should be the right size for my needs
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=220355050448
Yes that looks OK for multi hull racing. Do have a look on the OMRA web site, http://www.omra-uk.org/. Go into the bits & pices section/ Sales Wanted. Right at the bottom you will find a deep vee hullfor £28.00. If you go for this it means you will be able to race it OMRA Zclass races. Loads & Loads of fun!
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hi ive emailed the guy hope he replies those hulls look awesome do you have a rough guide on what's legal and not legal in that class of racing the dummy's guide really lol
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Z Class Omra boats must be 12 size engine standard. or Modified on a gearbox. If I remember all the rules are on the OMRA site under the rule section. There is loads of stuff which if you want to race you need to stick to. However Z class is suppose to be a Budget class boat, and therefore a dam good place to start and maybe move up to bigger boats. Heres two Pics of my boats. The Red one is OMRA D class. That has got a 26cc petrol engine in it.
Where abouts are you from?
All the best
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Also on the OMRA site is a fellow who will make a water cooled head for your engine, I'm afraid coiling around the head does not work very well.
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cool ime from hull east Yorkshire ill check that guy out about a water cooling head
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You will also need to buy a flywheel for that car motor,marine motors need them to keep ticking over unlike on a car,also means you can remove the pullstart and go to using the starter belt system asuming you have an electric starter :-).
Mart
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ime going to stick with the pull start for naw lol nice and easy their is a fly wheel already on the car motor that the clutch attached to ive left that in place to allow for idling
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could anybody point me in the right direction for a good engine pats mods accessory web site pleas
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No need to mod it at all, you'll just put extra stress on it. The flywheel on it won't do im afraid, you need the threading of the engine shaft for the coupling to attach to, clutch assemblys have an extender with no thread on it. New flywheels are quite cheap.
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hi i meant for flywheels and things not so much tuning
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As Andy said you need a marine flywheel,the extra meat on them keeps the motor spinning so you can throttle down without the motor stalling on you.Thats wether you wanna use pull start or not makes no difference.If you ran a car motor as is it would go fine at full whack but would have no low to mid range and would stall.You can get them made by that guy who makes the heads or you can search ebay you might find one.Some marine motors have clutches though as on the nitro vee so they dont need a flywheel.
Mart
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but my main problem is what prop to use
gwa84
As a guide, this chart was part of the 1992 catl from Prop Shop.
You may prefer to use DOG drive props from someone like Octura or a similar maker.
ALWAYS balance your props before running your boat.
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Only use dog drive if it is surface drive, and only use a dog drive on surface drive
If it is submerged drive, use a nut in front of the prop tightened onto the front of the prop
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picked up a hull today going cheep haven't got a clew haw good it is eny thoughts it is a "shadow" by SHG it has the prop shaft already mounted but needs rudder and engine mounts its been painted more times then Blackpool tower tho so needs work
eny ideas on motor size needed for this
might be considering getting another motor as it looks like its going to be cheaper then retrofitting this car one
ime waiting for a reply from the peeps about that other hull and water cooling head
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See what our very own Martin thinks of it ok2
http://www.modelboatmayhem.co.uk/My_models/02%20shadow.htm (http://www.modelboatmayhem.co.uk/My_models/02%20shadow.htm)
And what everyone else thinks
http://www.modelboatmayhem.co.uk/forum/index.php?topic=7763.0 (http://www.modelboatmayhem.co.uk/forum/index.php?topic=7763.0)
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cool so not bad buy then got it for 15 quid
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Yeah thats a very good buy :-))
You have an engine for it yet?
Probably looking at something like a Nova MX15 for that hull
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I've got an old enya 15 (marine) water cooled that you could have, that should do it (a little practice with a starting cord, or install a starting belt) PM me if you are interested, if you let me know what the thread is on your shaft and I'll make you a coupling. :-))
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no not got an engine yet
ive sent you a pm phil looking around the web they are very good reliable engines so would be a great intro my first ic boat
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Enya's are superb engines, I have an Enya 15 Aero engine. Lost a bit of compression due to age, but then again so has Phil ;) {-)
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Nothing wrong with my compression, its my flywheel thats gone wobbly :embarrassed:
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Mum says she hopes your piston's functioning correctly {-)
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You can tell her my big ends still looking good though :}
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Don't overdo the revs or your big end will blow O0
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{-) you lot crack me up {-) :-))
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hi all got the hull yesterday been inspecting it over and found a few things that need sorting as i already new this thing had been repainted god knows haw menny time lol so that will all have to be taken back the top section of the hull has been sanded dawn so many times it has become very thin so will need reinforcing with fibreglass cloth and resin
i will also need to remove and replace the water pick up and do a proper job of repairing an Exhausts hole at the rear
their has also been a bulkhead installed using a bit of wood and tones of filler lol which considerably adds to the weight of the hull so that will be removed also
and i will have to make a top engine bay cover for it
naw a few questions
what's the best engine mount for an enya 15 and if possible douse anybody have a link to an on-line shop for it please
and would it be possible to have a rudder on the back of the boat rather then fitting throw the bottom of the hull
if so which one would be best
also could i have a rear output prop and shaft on this hull serfice drive and agen what's best if i can and wher to get the parts from
thanks for all your help so far ime relay enjoying this project and your help is making it possible
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00144.jpg)
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00145.jpg)
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00146.jpg)
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00147.jpg)
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00148.jpg)
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00149.jpg)
(http://i275.photobucket.com/albums/jj298/wiplash84/DSC00151.jpg)
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I'll give Bill a shout and get him to post you some pics of the inside of our Z class.
Basically for the mounts you need 4 pieces of right angle aluminium 3-4 inches long, 2 pieces attached the engine itself, rubber mounts between the vertical face of the engine pieces and the hull pieces, the horizontal faces are bolted to mounting feet which are epoxied into the hull.
(http://i288.photobucket.com/albums/ll184/andyn_01/hardwa4.gif)
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Hi Gwa
Well you certainly like a challenge ... :-))
The easiest engine mount is a flat ally plate screwed to wooden blocks glassed into the hull - but this is also the noisiest so is not a good idea!
You can get rubber/ally mounts from either Prestwich or
http://modelmarinesupplies.co.uk/shop/product_info.php?cPath=40&products_id=398 (http://modelmarinesupplies.co.uk/shop/product_info.php?cPath=40&products_id=398)
For a slow revving engine, you would do well to stay with submerged drive although a surface drive may get you a bit more mph but will be (slightly) harder to set up properly. As you probably won't be racing you can even use plastic props on the submerged drive. If you use a solid shaft, you will need a rubber coupling "RC6" (another alternative supplier) -
http://www.prestwich.ndirect.co.uk/hdwrrubbersetc.htm (http://www.prestwich.ndirect.co.uk/hdwrrubbersetc.htm)
The transom mounted rudder will leave more room in the hull for a seperate radio box and a decent sized tank (although you will probably only use about a pint an hour). This might do the job
http://modelmarinesupplies.co.uk/shop/product_info.php?cPath=35&products_id=211 (http://modelmarinesupplies.co.uk/shop/product_info.php?cPath=35&products_id=211)
make sure you strengthen the transom inside!
There are also other suppliers both on Mayhem and the OMRA site http://www.omra-uk.org/links.html (http://www.omra-uk.org/links.html)
Hope that's enough to get you worried started %) {-)
Danny
Andy posted while I was typing (interesting that we both picked the same mount for you ... )
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col thanks for all the info ide love to see that z class would that be this boats category if i raced it
those rubber coupling's one end is square as i can see and the other i presume is threaded with a grub screw haw would you fit that to the prop shaft and engine shaft or is their a converter needed for the engine shaft to the square coupling
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Here you go mate this place has all you need drop him a line and delivery is in about 5-10 days.My advice is go surface drive its easier to setup using a flex cable and faster too.They sell all the hardware and have all the props you need right there and if you email him with your items he will do you a deal on postage.
Mart
http://cgi.ebay.co.uk/Aluminum-engine-mount-for-21-nitro-boat-engine-silver_W0QQitemZ300243221276QQcmdZViewItemQQptZRadio_Control_Vehicles?hash=item300243221276&_trksid=p4634.c0.m14 (http://cgi.ebay.co.uk/Aluminum-engine-mount-for-21-nitro-boat-engine-silver_W0QQitemZ300243221276QQcmdZViewItemQQptZRadio_Control_Vehicles?hash=item300243221276&_trksid=p4634.c0.m14)
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I'll give Bill a shout and get him to post you some pics of the inside of our Z class.
Basically for the mounts you need 4 pieces of right angle aluminium 3-4 inches long, 2 pieces attached the engine itself, rubber mounts between the vertical face of the engine pieces and the hull pieces, the horizontal faces are bolted to mounting feet which are epoxied into the hull.
(http://i288.photobucket.com/albums/ll184/andyn_01/hardwa4.gif)
5 Pic's of my Z class Boat. Fingers crossed the snow and ice holds off for sunday.
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been inspecting it over and found a few things that need sorting as i already new this thing had been repainted god knows haw menny time lol so that will all have to be taken back the top section of the hull has been sanded dawn so many times it has become very thin so will need reinforcing with fibreglass cloth and resin
A thought for you on rejoining the hull to the deck would be to consider using TIGER SEAL. It is a tenacious polyurethane adhesive and can be bought in a choice of colours in any Motor Accessory shop for less than £10. Also can be used to secure Battery Boxes and Fuel tanks. You can remove it with white spirit before it cures and after that point..... a chisel. Motor trade use it to secure panels etc
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The solid shaft you have in the hull at the moment is a 'local model shop' cheapy. It is a brass tube with phosphor bronze bearings at each end. The inner shaft is a solid rod, threaded at both ends (probably 2BA if the shaft is as old as the hull), one end screws into the ally part at one end of the rubber coupling and the prop screws onto the other end. Both are secured with locknuts. If you go down the solid shaft route, these are still available (although now in M5 thread) and are adequate for a sports boat. The M5 props are available in both plastic and ally in a range of sizes (you will probably need an ally 1818 or 1919, or plastic X40 to start with).
You would need to buy a coupling for that particular engine/shaft combination ie. threaded M5 one end and whatever thread the crank end has (ask the supplier if you don't know).
The rubber couplings with the grub screw are used with ball-raced competition shafts which have a plain 5mm end onto which a flat is ground. The grub screw then tightens onto this.
When fitting a submerged shaft, keep the engine as low as possible, leaving enough room to get a starter belt under the flywheel, and have the tip of the prop 1 - 2mm away from the hull underneath. The shaft you have will give some idea of prop and engine position and shaft length required.
A flexi shaft drive is NOT better, just different. It has its own problems ie strut height, shaft angle, rudder position, etc. Most opt for the submerged drive until they get used to the model, but to be honest, if you've got THAT keen, you will probably be looking for a faster engine and a sleeker hull!
Danny
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thanks for the input guys learning all the way ive ordered the engine mounts a load of clamps and some 30 Min epoxy and ive got a load of fibre glass and resin to reinforce the top section to get the hull prepared i think ill stick with a solid shaft for naw the one that's in it will need replacing as its not lined up by a long shot lol so will prob go for the more modern shaft with the flat fitting and better bushings
lots of work to be done but it all ads to the fun lol