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Author Topic: new petrol powered deep v mono scratch build!!  (Read 26169 times)

martno1fan

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new petrol powered deep v mono scratch build!!
« on: February 22, 2007, 10:43:55 AM »

Hi guys i just started my new build project ,its a 48" deep v mono hull made from plywood.Its done from free plans available from various sources and will be powered by a 28 cc strimmer engine with a walbro carb fitted.The hull will be epoxy coated outside to seal it and some glass tape and epoxy will strengthen areas in need of it like engine rails etc.Let me know what you think so far ,ive only dry fitted the rails and bulkheads togethr to check things fit before i start gluing .I will also be drilling a few holes to lighten up the rails and bulkheads.The boat will be surface driven using a flex cable connected to a stainles steel stub shaft that will run in a strut on the transome using a brass ferrule to join the two.I will be using an offset rudder too and the prop is a prather s280.
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #1 on: February 22, 2007, 10:21:42 PM »

Looks like fun.  My Avatar is a 48" Challenger but only has a 7.5cc nitro engine in it. I think I could just squeeze a sparky into it but might be short of headroom. :D
Its MANY years since I built a wood boat (my driving style favours a heavier material - but total stainless steel boats are banned, so I make do with GRP) ;D
Keep us posted on the progress.

Danny
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #2 on: February 22, 2007, 10:36:08 PM »

I love wood so its fun for me to build but i cant wait to get her finnished and on the water ,a mate has this same engine and while its not a speed demon for a 15 quid ebay bargain brand new it sounds like its gonna be good his was gps,d at 35 in 12" chop with a walb carb same as mine but a can muffler.Im having a pipe made by my mate who makes his own exhausts for 2 stroke bikes for the track so should work  he seems to know what hes doing lol.Hopefully with the pipe and a few mods here and there i could get nearer the 40 mark so that would be more than enough for a fun boat .Engine sounds better allready just with the walb carb fitted.More pics to come,nice boat by the way.
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #3 on: February 23, 2007, 08:37:16 PM »

I presume you've already found it , but if you haven't DM's site gives dimensions for width of cones, and with the application of a ruler to the screen, the rest can be worked out easily. ;)
http://www.prestwich.ndirect.co.uk/gaspipes.htm
He also provides a good bit on the theory of pipes at
http://www.prestwich.ndirect.co.uk/tunedpipetheory2.htm
theres also a Walbro carb setup sheet in the same section, although it sounds as if you don't need it  :D
If you can get it to 40 (hope you are talking MPH not these new fangled kilocycle things) you'll be welcome to come and THRASH mine ;D

Go fast.....er

Danny
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #4 on: February 24, 2007, 08:24:51 AM »

Thanks for the links i have daves site allready in my favourites!!,yes i meant 40 mph but that might be a bit hopefull with this engine but with mods to the ports who knows.35 sounds ok to me for a no name weedy so it will be a fun boat to drive hopefully.Where do you run your boat mate? im in blackpool by the way.I should get the rails glassed in today and the sides on hopefully so ill keep you posted.
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #5 on: February 24, 2007, 01:38:52 PM »

Heres a cpl of pics of the sides glued in place ,im just about to glass the rails in and test fitted the engine to see how she fits PHEW just fits in there engine goes nice and low which is a good thing now all i need is to make the mounts and attach the rubber feet to it theres just enough room as the bolts where ill mont the engine have enough room either side.the front mount will fit on the red shroud for the clutch ,thats how a mate did his using this engine and it works ok .
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BJ

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Re: new petrol powered deep v mono scratch build!!
« Reply #6 on: February 24, 2007, 03:01:55 PM »

Have you heard of Ian Williams Tuning? May be not quite what you want but there is a program that you can run - see the "Free Download" . The text line is about midpage, look for; We now have a simple 2 stroke expansion chamber design program.   Free download here
Site is http://www.iwt.com.au/MOTA.HTM

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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #7 on: February 24, 2007, 04:12:57 PM »

Thanks for the link mate im not great with engines to be honest,my mate mods 2 stroke bikes and hes building me a tuned pipe for this from alluminium i will run it as it is for a while then maybe get him to mod the ports etc later on.
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #8 on: February 25, 2007, 03:11:03 PM »

Hi Martno1fan (or may I be less formal and call you Mart)
Neat looking engine and looks to fit a treat!  How are you cooling it? It looks as though a water jacket might be difficult so I guess you'll be sticking to air cooled.  It will give you a good excuse for not slowing down ;D
When I buy racing engines, I am too tight to wear them out just pottering round the club lake so tend to just set them up and stick them back in the car (after answering the obligarory questions from local children - "How fast does it go?" and "How much is it to buy?" ;D
I run most weekends wherever the races are ;)  This year its Torquay, Bristol, Telford, Stevenage, Tamworth - home club, Tredegar (Mid Wales), Burton on Trent, Weymouth, Milton Keynes, Eastbourne, and Lake Windermere.

I don't know anyone who races from Blackpool and "DM" is not a "real" offshore racer, he mainly does World Champs and big internationals :D
Given the length of pipe you'll need (12 - 15K rpm??), it looks as though you'll end up with a LOT of pipe hanging out the back :D
Keep up the good work
Danny
 
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #9 on: February 25, 2007, 04:49:05 PM »

Hi Danny ive been called much worse lol hehe,yes it will be air cooled which wont be a problem as it will be run open hatch maybe just a screen with a few air holes if needed as for the pipe thats not my department my mates sorting that out,as for revs i dont think thats a problem this thing revs pretty well and my mate listened to it on video and reckons it sounds pretty good.although the carb isnt set up properly yet but ill do that when i hit the water. ill probably run it with the can muffler for a while till he gets my pipe done.the pipe will be ali and hes hydroforming it for me.the engine isnt fixed in yet its just sat in there to get an idea of how it fits in the boat.
mart
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #10 on: February 25, 2007, 05:10:58 PM »

hi heres a link to my engine running let me know what you think.also feel free to check out my other vids of my lads pt boat i scratch built him and my sail boat i also scratch built.
http://http://media.putfile.com/boat-engine
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #11 on: February 25, 2007, 05:50:35 PM »

Good videos Mart
Lovely tickover - that engine will just love a decent pipe on it (then you'll really hear it rev)
So - I've "found" HIS secret practice lake :o  How does he get a sparky to go that fast!!! I still say that anything more than 2" waves will have it over though.  The World Champs are ALWAYS held on specially designed FLAT lakes, so he should be alright :D
D
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #12 on: February 25, 2007, 08:40:00 PM »

Why you asking me how he gets em to run that fast lol?,7.3hp that engines putting out according to his site.I doubt hed be running it that fast offshore either lol but 5 world titles speak for themselves i guess,mind you at  what that engine costs ill stick with my chinese no name weedy for a bit longer haha.
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #13 on: February 26, 2007, 04:36:31 PM »

few more pics for yaa,the decks not fastened on just tacked and taped hows she looking?.
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #14 on: February 26, 2007, 06:43:46 PM »

Bulkheads vertical, hull symetrical - aarrgh, I'm having none of it ;D
I'll be wodering why I spend 140 on a plastic one soon!

Hope those sides are 50mm at the widest point or you won't be able to race it in OMRA (2006 rule)  :(

Looking good so far. Keep it up!
Danny
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #15 on: February 26, 2007, 07:47:52 PM »

Bulkheads vertical, hull symetrical - aarrgh, I'm having none of it ;D
I'll be wodering why I spend 140 on a plastic one soon!

Hope those sides are 50mm at the widest point or you won't be able to race it in OMRA (2006 rule)  :(

Looking good so far. Keep it up!
Danny

Mate when you say widest point of the sides which side do you mean the side of the boat as in 50 mm high? or the deck sides where engine bay is?.Anyway the sides ar 60 mm high at highest point and the deck sides are a little under 100 mm so either way im good to go!! one problem though i cant afford to go racing nor can i travel to all the venues lol so ill just have to play on my own for a bit yet !!.The boats 48 " long x 15 1/4" wide thats 1,220 mm x 390 mm give or take a cpl of mm lol.hull weighs under 6 lb right now.
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #16 on: February 26, 2007, 09:11:56 PM »

Now, I know I'm going to sound a right prat to the ex mariners but what the h*ll,
its the bit between where the bottom of the hull (chine?) meets the sides to the bit where the sides join the deck.  I think it might be called "Freeboard" but I'll keep my head down just in case :D
Anyway as long as it's 50mm at the widest (deepest?) point, it's OK. Sounds as if yours would be OK anyway.
It was originally brought in to stop out-and-out multi boats entering, but DM took it personal because his newly designed "offshore" boats didn't qualify as they have hardly any 'freeboard'.
At 15.25" (how DO you get fractions on this keyboard?) wide, it should be MEGA stable!
Sorry you won't be doing 'the circuit' - YET ;)  but at least try to get to Windermere on 22/23 September, its a great venue and it's "just up the road" from you :D
Danny
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #17 on: February 26, 2007, 10:47:17 PM »

yep free board is right lol racing isnt my thing to be honest but ill see what i can do about the windermere thing.i guess i could just watch you guys lol.maybe ill bring the boat and find a quiet corner all to myself after all its a big lake hehe.i know nothing about omra or racing and there are no other gas boats that i know of local to me to race anyway.if this boat runs well i will be building another so me and my lad can have some fun together .who knows maybe someone else will want one built lol.i love building boats as when i left school i worked at a boat yard and qualified as a time served boat builder(shipwright)before moving on to been a joiner so i guess working with wood is in the blood now.
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glennb2006

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Re: new petrol powered deep v mono scratch build!!
« Reply #18 on: February 27, 2007, 02:23:36 AM »

Or blood on the wood?? :o

Hello Martin by the way.

What's happened to the cooling fan off the motor, or was there not one fitted when you got it? Think it may need one, unless you can get it  water cooled.

Hi Omra 85, had a look on the OMRA web site and did not notice a section for larger spark ignition engines - would a 26cc Zenoah in a Miami 55 qulaify for entry?

Sorry for going off subject a bit.

Cheers,

Glenn
 
PS, boat looking canny by the way Martin.
(Funny, there's a lad called martno1fan building something similar on the RC Universe forum - but his is running on propane I guess. Well, he said it was gas.)

Hehe - only winding you up...
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #19 on: February 27, 2007, 08:42:02 AM »

Or blood on the wood?? :o

Hello Martin by the way.

What's happened to the cooling fan off the motor, or was there not one fitted when you got it? Think it may need one, unless you can get it  water cooled.

Hi Omra 85, had a look on the OMRA web site and did not notice a section for larger spark ignition engines - would a 26cc Zenoah in a Miami 55 qulaify for entry?

Sorry for going off subject a bit.

Cheers,

Glenn
 
PS, boat looking canny by the way Martin.
(Funny, there's a lad called martno1fan building something similar on the RC Universe forum - but his is running on propane I guess. Well, he said it was gas.)

Hehe - only winding you up...
the cooling fans fully intact no probs there mate!!,never heard of that guy dunno who he is lolol.dont know where your looking for the fan mate but its all there if you look closer hehe.maybe the clutch housing is obscuring the view lol.
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glennb2006

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Re: new petrol powered deep v mono scratch build!!
« Reply #20 on: February 27, 2007, 11:12:56 AM »

 8) Just my eyes then Martin, couldn't see the fan. Well that's OK then.

When's it going to be finished?

Got your PM by the way - wouldn't dream of it. Much.

Glenn
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #21 on: February 27, 2007, 11:27:10 AM »

Glen not sure when it will be ready i still need a stuffing tube and servos and battery holder and batterys for it.apart from that i have all my gear.Im making my own rudder from ali billet but hopefully if i get enough time on her she could be ready for Aprill .
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #22 on: February 27, 2007, 09:19:42 PM »

Hi Glenn
The 26 in a Miami would be fine.  The 'D' class caters for spark ignition up to 50cc! A lot used to run the old Kawa 35s but many have now gone over to the 26's as the boats are smaller (under 60") and the speed is as good plus they're easy to tune.
If you look on the OMRA site - "2006 season", then "AA-D classes Championship Table" then scroll down to "D" class, you will see that there are 33 different racers all running sparkies :o
You can also look at "Photographs" then go down to "D" class - they are mostly 26's.
Go for it ;)
Danny
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martno1fan

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Re: new petrol powered deep v mono scratch build!!
« Reply #23 on: February 27, 2007, 11:06:24 PM »

by the way danny you will know mr pope? he made a wise crack about one touch and my boat will disintegrate.cheeky sod if i come to windermere maybe ill give him a game of chicken i know whos boat will come off best lol.this thing will be stronger than a glass hull any day might be fun lol  ;D.
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omra85

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Re: new petrol powered deep v mono scratch build!!
« Reply #24 on: March 01, 2007, 08:47:01 PM »

Oh yes, I know Gary!  He the current D class champion in OMRA (but if he's not reading this - it was a fluke - he won ONE race, came second once and got SIX thirds ;D )
As for it coming apart - they all do that if you hit them hard enough ;D  The secret is to stay out of the way, it took me 20 years to learn though ::)
I've managed to take some pics of my set ups.  They are on Photobucket. Hope this link works :-\
http://i176.photobucket.com/albums/w191/omra85/CMB45topSmall.jpg
Danny


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