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[andyn]

Hello and welcome to my build thread. Looking around the site there is great interest in the OMRA racing side of things, but no threads on actually how to build one. I decided to take up the challenge, I am showing this as guidelines of what to do, and am seeking knowledge on what I should do all the time from people at the club, mainly Greg, who has been model boating since what appears to be the dawn of time, because I have yet to meet anyone more clued up on IC boats.  I offer this information to you as not "you should do this and this only", because everyone has their different ways of going about doing things. I would also like to point out that I'm only 17, and have only been boating for 3 years now, so I'm far from the best out there, but contrary to popular belief I do listen to everything that I'm told, and absorb it like a sponge....

I bought this boat, a Crusader 3, moulded by Bernard Holder, at the Stevenage OMRA race last year. The hull is for up to a 7.5cc (.45 cu i), and is 42" long by 12" wide. I've been talking about making this thing for ages now, and have finally got round to doing it. Many engines have been suggested over time, among which Picco .45's, OS .45's, and a Zenoah, the idea of which was rather forcefully rejected by just about everyone except Bill and Greg, even the maker had words to say about it (see the Mental Makara video on my site for why, except instead of only 2cc more than suggested, I was going for 18.5cc more...). I have settled on a Novarossi CX61, bought off Greg, Still too big but plenty controllable enough.

I must admit beforehand that I am useless with Polyester Resin, it ends up everywhere, and doesn't look good. But it's very cheap and reasonably light. I used Talc to thicken it up when layering for strength.

This so far is two day's work.

Enjoy


The finished Boat:


My boat, control and engine.


Engine in hull


Engine and MAC pipe


Marking the hull


Filling a chip in with P38


Rudder tube installed


Rudder installed


Components in boat.


The 'destructions'


Having read the destructions, I sanded the filler in the chip down


Pilot drilling the driveshaft slot


Cutting filing and enlarging the slot


Cutting and fitting the strut


Following a trip to school with engine and strut in bag, the mounts were filed with flats, to keep them in the boat, and the strut was cut down. This is the P38 over the first layer of Polyester Resin.


Polyester resin was used to secure all parts in, before P38-ing, and a coat of thickened Resin.


Tacking the mounts in with P38, so the engine can be removed.


Building up Polyester Resin and P38 around mounts.


Same as above, but on the other side.


Building up P38 and resin around the shaft, a Prestwich model, but heavily modified for me by Ralph, the club metal man. He changed the bearing feed from a grease nipple to oil feed, cut the shaft and tube to length, brazed on a new tube that actually fits properly onto the strut, and many, many more things that I can't think of right now. All his work is beautifully done, very neat, and he polishes everything afterwards. For a very handsome price too.


Resin, Talc and Glassfibre matting around the mounts. I did 3 layers of Resin and glass, and 3 layers of P38 on each mount. It's VERY strong.


Slightly neater one...


The penultimate coat of Polyester Resin and Glass Mat, mum thought I was bleeding everywhere...


The finished mounts, where I have got to so far.



That's as far as I have got so far, after about 6 hours work. More will follow shortly, Equipment to be fitted is:

• Radio box, a highlander metal sandwich tin, with latching lid. Race proven and crash tested in Bill's Makara, so it's good enough for me. will be on 5" rails made from 1/8" ply.
• 2 Futaba S3003 servo's, one for throttle and one for the remote mixture needle.
• 1 Cirrus CDS751 servo, for rudder. Cheap at £20, standard size, digital, metal geared, and twice the torque of a S3003
• Spektrum radio gear, no arguments please...
• The biggest Rx battery pack I can possibly fit in, looking at a 5 cell Sub C pack from Ansmann, with Rx leads and Tamiya connector for charging already fitted
• Sullivan Snakes for Throttle and remote needle, and Du-Bro Heavy Duty joints and rods for the rudder
• 2 fuel tanks, big as I can get in, and most likely a float chamber too
• A support for the pipe
• Pool Noodles!

I'm toying with many ideas for paint jobs, but I personally think it looks like a PT boat of sorts, so I think it will be painted a deep green, and I'll get RCGraphics to make me up some big shark mouth stickers for the front. The inside will be sprayed with Halfords grey primer, and fuelproofed. This is so I can see things in the bottom of the boat when I drop them...

Next job will be to fit radio box in on rails, and then join the deck to the hull.

[SteamboatPhil]

Keep going Andy, nice job so far, should raise a few eybrows at Llanberis   

[omra85]

Hi Andy
Good idea to put your build on here - might encourage others to have a go!
Couple of small hints -

be prepared for LOTS of rowing  - your picture of Andy R's boat (the finished boat) shows the 'normal' position for a Crusader 3 with a tuned 21 on a pipe - ie. more out of the water than in it 
Your engine is THREE times as big and is a very powerful racing engine (see Ian's Mental Makara vid - oh yes, you shot it  ).
Are you SURE this is the right engine for this hull??

Change the rudder before you get too far.  The brass one will bend as soon as you hit anything (and we ALL do) also the plastic outer tube will crack or shear off on impact. Both Bernard (and Dave and Ian and Tony) sell the stainless type.  You could make your own (which would be good practice for silver soldering) based on their website pictures.  The mount tube needs a substantial 'washer' at the bottom (min 12mm) to spread impact load.

BTW the grease nipple in the top bearing housing usually gives access to the grub screw holding the shaft thrust collar. Does yours have a top collar?  If so, can you still get at the grubscrew?

Good luck.
Danny
 

[andyn]

Danny, thanks for the rudder tip, I'll change it over, I have a brass tube and I'll get Ralph to make me up a rudder.

The engine is a bit big yes, but that's all part of the fun Ian brought the Makara along last sunday, and it has been 'improved' ( as in, not in entertainment values, I prefered it before...), and we put a small concrete bouy weight up the front which calmed it down a lot. Before this, that engine has also been in a Manta, and a Crusader 2.

The grease nipple has been removed, as I can't be bothered with squeezing grease in and whatnot, and replaced with a tube with a thread in it, so I can have a dripfeed. There is no grub screw in it.

Next update shall be about 2-3 weeks, when I get some money and can buy the radio box, pushrods, and the steering servo.

[Bill D203]

Ho Ray!!!! We "Gregg and I was begin to think never going to start"  Looks OK so far. Danny is spot on about the rudder set up. You need a bomb prof rudder. Don't forget to add extra foam around the radio box lid.
I expect to see great things going on the build when I am away. Well Done. Don't forget to get some driving done on the Z boat so your up to speed for the Stevenage meet in May.

[omra85]

Andy
How are you rigging the mixture on your radio?  I thought the Spektrum (and the Futaba 6ch) only had the 2 sticks for the proportional channels and on-off switches for the rest.
Glad Ian's sorted - but a breeze block in the nose is a bit drastic 
Danny

[andyn]

Ah, that's where my masterful plan comes in....

On my Rc Car sim on the computer, the only way I could get my trannie to work with the sim was to have throttle on RH stick, as well as steering. I played around with this for a while, and found I much prefer it to independant thumbs, as you can very easily adjust your speed while steering. I short after converted all my cars to this system, and won my first club race a week later. So the Throttle and Steering shall be on the RH stick, and the mixture on the LH, with the ratchet. Simples

Ian's Makara still takes off, just as not as much as before. He's still deciding to turn way too late for my liking, and still insists on standing on the waterline when the rest of us are hiding...

Still, I've worked out what he needs to do, get another one and stick them together, transom to transom

[omra85]

Ah - the joys of youth!  Takes me all my time to work out which is the rudder 
Hove will be a good place to see all the one's (including me) who haven't done any practicing since last year 
Let the fun begin .....
Danny

[glennb2006]

Looks OK Andy,

one tip for you, when using the polyester resin, put some masking tape around the area you are working on, then, shortly before it goes off, you can remove the tape along with any excess drips to try to keep your hull neat and tidy inside.
I'll have a look around the workshop for you to see if I have a spare rudder you can have if you want it, no guarantee mind - see what I can find. While you are on putting holes in the hull, don't forget to put one in for the water pickup.

What size fuel tank are you going to need to run in this to last you half an hour?

Glenn

[andyn]

Water pickup is next, I'll do it tomorow afternoon, made one up today

That would be very good of you, thank you very much, the one I have at the moment is a 2.5" blade.

As for tanks, ermm...   ....big...

I'm going to have at least two of them anyway, to fit them in, and a float chamber too. The ones in Ian's Manta with CMB .45 are about 1/3 gallon each, so if I can fit some of those in, I will.

[glennb2006]

Water pickup is next, I'll do it tomorow afternoon, made one up today

That would be very good of you, thank you very much, the one I have at the moment is a 2.5" blade.

As for tanks, ermm...   ....big...

I'm going to have at least two of them anyway, to fit them in, and a float chamber too. The ones in Ian's Manta with CMB .45 are about 1/3 gallon each, so if I can fit some of those in, I will.

OK Andy,

good and bad news, the rudder I thought I had I do not seem to anymore, I might have given it to someone at the local club, I do however have a rudder blade and shaft in stainless that you are welcome to, the blade is approx 40mm high, by 22mm wide at the top edge and 35 at the bottom. The rudder shaft is 4.76mm diameter and is 65mm long. I have no rudder tube for it though I'm afraid.

Tanks: good news here, I have a second hand Prestwich tank, hold 2.6litres when brimmed, has the recess in the centre for a tuned pipe. The dimensions are (roughly): 230mm long, 200mm wide, height at front 100mm, height at rear 75mm.

It has a baffled pick up in it and pressure feed point.

Yours for the cost of postage if you are able to use them. 

I think fomr memory that 2.5 litres will last a .61 for half an hour, Danny can jump in here and confirm, he runs methanol still.

Glenn

[andyn]

Thanks for the offer, but I won't be able to fit a centre tank in, Itll have to be two large tanks down the side of the boat. I think I may have a rudder for i actually, I'll take a look

Thanks anyway

Andy

[glennb2006]

OK, not sure why the tank won't fit. Never mind.

All the best with it. Post if you are looking for other bits and pieces, I may have some stuff around. Been trying to clear some of my excess to requirement stuff I have been accumulating.

Glenn

[andyn]

Had a look, and I dont have a rudder for it, it would be very much apreciated if you had a spare one.

I'm after two tanks, up to 2.5" wide, 3.5" tall, and up to 15" long. I think I shall have to make a pair up in school. A centre tank won't fit in, as I'm having the radio box in the middle, and not using the one Bernard supplied.

[glennb2006]

OK, send me a private message or email with the postal address and I will send you the rudder blade.

Glenn

[martno1fan]

Andy try those plastic bottles you can pick them up cheap and they make great fuel tanks if you buy some small fittings for them similar to the ones dave marles sells on his site just check them first with fuel to make sure theyre not going to melt  .
Mart
http://cgi.ebay.co.uk/PLASTIC-BOTTLES-10-X-500ml-5-BOTTLES-FREE_W0QQitemZ270345197046QQcmdZViewItemQQptZUK_HealthBeauty_Other_RL?hash=item270345197046&_trksid=p3286.c0.m14&_trkparms=72%3A1683%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

[SteamboatPhil]

Danny, when's the meeting in Hove as I'd love to come along and see just what you nutters get up to 

[omra85]

Hi Phil
Hove AA-D classes is 15th March with 'Z' class being held in Sat 14th Mar.
The OMRA calendar is at
http://www.omra-uk.org/calendar.html
then, if you click on venues at the top, it will take you to a 'click' map and then to the venue details.
Can you get a flash steamer to run for 20 mins?  We could start another OMRA class for you 
Danny

[SteamboatPhil]

20 mins eh, its food for thought
I will go along and have a look both days (I'm in Brighton that weekend) camera and big lens, will you be there 
(I will wear my mayhem badge of course)

[SteamboatPhil]

Fuel tanks on flea bay at the moment if you still need some Andy
Item number: 180334333211
 

[omra85]

See you Sunday then Phil - look for number 85 (on cap or boats).
Mines the daftest boat there ...... ? 
Danny

[andyn]

I've got another boat to work on inbetween working on the Crusader, A small 'Cathedral' hull, don't know what it is, but it's 16" long and 5" wide. I believe its a fast electric hull, but it's getting a Kyosho GX.16, so it can be as mad as the Crusader will be. So far I've fitted the front bulkhead of the radio box, cut down the shaft to 2.5", and fitted the rudder and W/C pickup.

First though, what do the assembled company think of this idea for an oiler? It's an old film canister with a hole in the bottom (and a pinhole in the lid for pressure release), secured on by two layers of silicon tube, is flexible on the shaft, but takes a good yank to get it off. Pics below.

[glennb2006]

Andy, just spotted a problem, the coupling you show is not going to last long with the amount of misalignment there, the pins should be right into the bushes and the engine should be mounted so the crankshaft is, as far as practible, in line with the prop shaft.

Easier to cut the mounts and refit now before you get the deck on.

Glenn

[ids987]

Andy,

Sorry to agree with bad news, but I have to say that I'm with Glenn on the shaft alignment. Any solid shaft needs to be aligned as close to perfect as you can possibly get it. You need to either get the coupling straight before you start (so that you can use it to line up the engine and shaft), or use some form of solid coupler. The coupling is just as good - if it is true, and you can set it straight enough. What you need to aim for is; start with the shaft slid away from the engine (enough that it is totally removed from the coupling), and with the grub screw(s) fully unscrewed or removed from the coupling. Slide the shaft towards the engine. The shaft should slide freely into the coupling, and you should be able to rotate it freely whilst fully inserted    (or as freely as the fit of the shaft in the coupling will allow). You should then be able to slide the shaft out, rotate the engine, and do the same again. Tack everything in place when you have it aligned to that level, re-check it when it's dried - then fix it in properly.

Feel free to drop me a line if you want me to attempt to explain it better.

One question, it may be an optical illusion, but it looks from the photos like the end of the prop tube will be quite close to the rudder ??

Ian

[andyn]

Problem solved, put a couple of washers in the rear mounts between rubber and mount, thanks guys

I think your eyes are going funny Ian, there's just over 3" between the two of them...