Model Boat Mayhem - Forum

Dry Dock / Shipyard: Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: gwa84 on February 03, 2009, 03:14:49 PM

Title: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 03:14:49 PM
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
Title: Re: hi all just joined looking for some help
Post by: dan on February 03, 2009, 03:37:35 PM
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.....
Title: Re: hi all just joined looking for some help
Post by: Bill D203 on February 03, 2009, 05:24:47 PM
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.
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 06:31:23 PM
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
\
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

Title: Re: hi all just joined looking for some help
Post by: dan on February 03, 2009, 06:39:59 PM
again the wesite i gave above has a few deep V hulls  :-))
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 08:17:34 PM
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
Title: Re: hi all just joined looking for some help
Post by: Bill D203 on February 03, 2009, 08:37:41 PM
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!
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 09:49:22 PM
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
Title: Re: hi all just joined looking for some help
Post by: Bill D203 on February 03, 2009, 10:01:34 PM
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
Title: Re: hi all just joined looking for some help
Post by: andyn on February 03, 2009, 10:03:20 PM
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.
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 10:08:27 PM
cool ime from hull east Yorkshire ill check that guy out about a water cooling head
Title: Re: hi all just joined looking for some help
Post by: martno1fan on February 03, 2009, 10:36:05 PM
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
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 10:46:21 PM
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
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 03, 2009, 11:01:14 PM
could anybody point me in the right direction for a good engine pats mods accessory web site pleas
Title: Re: hi all just joined looking for some help
Post by: andyn on February 04, 2009, 12:13:44 AM
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.
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 04, 2009, 12:53:25 AM
hi i meant for  flywheels and things not so much tuning
Title: Re: hi all just joined looking for some help
Post by: martno1fan on February 04, 2009, 11:02:05 AM
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
Title: Re: hi all just joined looking for some help
Post by: BJ on February 05, 2009, 11:43:37 AM

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.
Title: Re: hi all just joined looking for some help
Post by: andyn on February 05, 2009, 02:35:02 PM
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
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 05, 2009, 10:36:51 PM
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
Title: Re: hi all just joined looking for some help
Post by: andyn on February 05, 2009, 10:41:18 PM
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)
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 05, 2009, 10:51:01 PM
cool so not bad buy then got it for 15 quid
Title: Re: hi all just joined looking for some help
Post by: andyn on February 06, 2009, 11:01:32 AM
Yeah thats a very good buy :-))

You have an engine for it yet?

Probably looking at something like a Nova MX15 for that hull
Title: Re: hi all just joined looking for some help
Post by: SteamboatPhil on February 06, 2009, 05:28:04 PM
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.   :-))
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 07, 2009, 02:34:09 AM
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
Title: Re: hi all just joined looking for some help
Post by: andyn on February 07, 2009, 01:06:19 PM
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 ;) {-)
Title: Re: hi all just joined looking for some help
Post by: SteamboatPhil on February 07, 2009, 02:59:33 PM
Nothing wrong with my compression, its my flywheel thats gone wobbly   :embarrassed:
Title: Re: hi all just joined looking for some help
Post by: andyn on February 07, 2009, 03:04:35 PM
Mum says she hopes your piston's functioning correctly {-)
Title: Re: hi all just joined looking for some help
Post by: SteamboatPhil on February 07, 2009, 03:20:13 PM
You can tell her my big ends still looking good though  :}
Title: Re: hi all just joined looking for some help
Post by: andyn on February 07, 2009, 05:40:50 PM
Don't overdo the revs or your big end will blow O0
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 08, 2009, 07:26:56 PM
 {-) you lot crack me up {-)  :-))
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 10, 2009, 09:33:00 PM
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)


Title: Re: hi all just joined looking for some help
Post by: andyn on February 10, 2009, 10:34:35 PM
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)
Title: Re: hi all just joined looking for some help
Post by: omra85 on February 10, 2009, 10:49:21 PM
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 ... )
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 10, 2009, 11:27:59 PM
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
Title: Re: hi all just joined looking for some help
Post by: martno1fan on February 11, 2009, 09:34:02 AM
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)
Title: Re: hi all just joined looking for some help
Post by: Bill D203 on February 11, 2009, 01:31:07 PM
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.
Title: Re: hi all just joined looking for some help
Post by: BJ on February 11, 2009, 03:06:49 PM
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
Title: Re: hi all just joined looking for some help
Post by: omra85 on February 11, 2009, 07:10:01 PM
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
Title: Re: hi all just joined looking for some help
Post by: gwa84 on February 12, 2009, 05:08:59 PM
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