Engine for Model Boat

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daltontechnogeek
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Engine for Model Boat

Post by daltontechnogeek » Thu Jan 05, 2012 10:44 pm

I'm building a model of the Bluebird K7 in my Drafting class. I've been left to the propulsion. I need to build the most powerful pulse jet possible to fit into 35" in length. This engine also has to be relatively easy to make without the need of complex CNC mills.
Can anyone help?

nitro
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Re: Engine for Model Boat

Post by nitro » Fri Jan 06, 2012 2:26 pm

Yes.A z-jet.it Zanin Z26 from italy .I think thay would be a good Pulse jet 16.5LBS static thrust.

daltontechnogeek
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Re: Engine for Model Boat

Post by daltontechnogeek » Fri Jan 06, 2012 10:47 pm

are there any other engines of this size which have a little more "Oomph" like around 25 lbf?

metiz
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Re: Engine for Model Boat

Post by metiz » Sat Jan 07, 2012 12:28 am

My valveless M25 has a max thrust rating of 26.4 pounds. the engine's 1007mm long I think from the top of my head
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daltontechnogeek
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Re: Engine for Model Boat

Post by daltontechnogeek » Sat Jan 07, 2012 5:19 pm

Great to know, I'll look for some M25 plans
I really need something a little shorter near 889mm, so valved is probably the only way to find one so short.
I just used the Pulse jet calculator from the download page and found that 22lbf = approximately a 35 inch pulsejet
is this calculator at all accurate and is there any way to augment it without extending the length?
Would a Melot Nozzle help at all?

daltontechnogeek
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Re: Engine for Model Boat

Post by daltontechnogeek » Mon Jan 09, 2012 10:41 pm

Any other input?

New questions, what would be the fuel consumption of this thing?
and how do I make the intake?

daltontechnogeek
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Re: Engine for Model Boat

Post by daltontechnogeek » Sat Jan 14, 2012 1:22 am

I guess this forum is kind of dead :3

kevin lee
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Re: Engine for Model Boat

Post by kevin lee » Sat Jan 14, 2012 2:25 pm

are you asking about the m25 valveless pulsejet?

if so it is valveless and there is a thread on the first page of the valveless forum, i asked questions yesterday and got a response from the designer!!

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Re: Engine for Model Boat

Post by daltontechnogeek » Sun Jan 15, 2012 5:03 pm

Nice!
But, I was originally asking in the OP whether anyone knew of any valved designs that were around 35" in length and produced 20-25 lbf of thrust
I used the calculator on the front page and have used those dimensions, and need to know also how to build the intake on a highly efficient petal valve system.
Also had questions on if there were any tips or tricks to augment the thrust of the PJ without extending length.
And another question of what fuel is best to use and how to inject it

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Re: Engine for Model Boat

Post by metiz » Sun Jan 15, 2012 7:49 pm

You can increase the thrust by I think 50% by injecting water into the eninge (thus generating steam). Normally this isn't practical since you have to haul the water with you but since the engine will be mounted on a boat this is an ideal solution
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daltontechnogeek
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Re: Engine for Model Boat

Post by daltontechnogeek » Mon Jan 16, 2012 4:00 am

Magnificent!
Any Idea how it is done?

kevin lee
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Re: Engine for Model Boat

Post by kevin lee » Tue Jan 17, 2012 8:11 pm

Sorry i miss under stood and realise that my post sounded really really sarcastic :roll: not intentional sorry.

kev

ps water injection has been talked about within the forums, probably easiest too have a search but use advanced search and search water injection but select topics instead of posts!!

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Re: Engine for Model Boat

Post by kevin lee » Tue Jan 17, 2012 8:18 pm

i guess you just pump a small misted amount of water into the cc. iirc the waters volume multiplies by something stupid like 1600 x. for example 1ounce of steam takes up 1600 times more space than 1ounce of water.

please do a search though cose my memory could be totally wrong ha

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Re: Engine for Model Boat

Post by metiz » Tue Jan 17, 2012 8:53 pm

I forgot about your post, and also to press "submit", apparently. You can try to get the engine to suck the water up itself just like to fuel or if that doesn't work, use a small 12v aquariumpump and a ballvalve to pump it in.
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daltontechnogeek
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Re: Engine for Model Boat

Post by daltontechnogeek » Tue Jan 17, 2012 11:53 pm

@kevin lee: Nah, post sounded fine to me :)
plus it helped me find the info on the M25
@both: I"ll search for the thread, this Idea is brilliant especially considering it'll be on a hydroplane.

Other questions still, would welding seams be any detriment to the engine(like on the inside)?
and what gauge metal should I use?

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