Please put your "I am new and need help" question here.

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kdiver58
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Noob .. Alcohol fuel pump

Post by kdiver58 » Thu Aug 27, 2009 11:37 am

I want to make a valveless pulse just that will run on Methanol .. I've done some searching and have not ended up with much material. I am a tool and die maker so making the engine is just a matter of doing it. What are you using for delivering liquid to the engine? Thanks .. K

m1tch
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Re: Noob .. Alcohol fuel pump

Post by m1tch » Thu Aug 27, 2009 11:42 am

kdiver58 wrote:I want to make a valveless pulse just that will run on Methanol .. I've done some searching and have not ended up with much material. I am a tool and die maker so making the engine is just a matter of doing it. What are you using for delivering liquid to the engine? Thanks .. K
It seems that most people are using copper tubes to run propane for smaller engines and LPG for the larger engines, seems that there are lots of different ways to get the fuel in, some are just pipes, some have pipes with holes and some are full on custom jets lol

kdiver58
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R/C using propane ?

Post by kdiver58 » Thu Aug 27, 2009 11:52 am

The R/C people are also using propane? I was thinking of Methanol for the ease of portability.

Mike Everman
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Re: Please put your "I am new and need help" question here.

Post by Mike Everman » Thu Aug 27, 2009 7:15 pm

Mitch, yes straight intake.

Kdiver, I've not made a liquid fueled valveless. It is almost certainly required to have a fuel pump and spray injector, as it is very difficult to get one to self aspirate fuel like a valve type does (though I know possible). There are some good RC jet pumps out there, but special attention needs to be paid to whether they will survive the fuel you use. Methanol is the choice for small motors, with larger being capable of gasoline, white gas and kerosene.
*a good deal of experimentation required*
Best bet is to get your motor running on propane and get all the idiosyncrasies of starting and running out of the way, then start playing with liquids. I personally don't like the safety issues around pressurized liquid fuel delivery, but I'm also not trying to fly the things.
Look for posts by James Irvine on the subject. He's tested scads of pumps and spray nozzles and has successfully done this.

It's not the end of the world to start on propane, then switch over to liquid when it's warmed up, as a natural course of using a jet. It's how all the micro turbojet guys get their motors going.
Mike
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kdiver58
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Liquid Fuel

Post by kdiver58 » Thu Aug 27, 2009 9:23 pm

Thanks for the reply .. while I've not gone through all of the posts by Irvine.J .. The ones I have gone through do show liquid fuel would be a major problem. I you have guessed I was asking about fuel pumps and fuel delivery systems for the Methanol compatibility problems. Now if I might bother you for one more answer.. I link to propane fueling of a Valveless Pulse jet R/C plane. Thanks ... K

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Re: Please put your "I am new and need help" question here.

Post by Mike Everman » Thu Aug 27, 2009 11:36 pm

In my opinion, propane fueling of a flight model is not practical, but doable for a short run time. Problem is that small cannisters cool off so fast that you lose your pressure. Look at the Laird Chinese plans. that is the most notable valveless made to run on gasoline, and the details of the fueling are on the plans.
Mike
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wildbillkelso
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Re: Please put your "I am new and need help" question here.

Post by wildbillkelso » Sun Aug 30, 2009 6:55 pm

Hi all.

I would like to build a small thermojet to power a small and light remote control hydroplane, The boat weighs approximately 250g. My idea is to build a thermojet and use a modified blow torch to fuel it. I have modified a servo for 4x 360 degree turns to enable me to open the valve for throttle control. Is a blow torch gas canister that is commonly used for plumbing suitable, or should I consider some other form of fuel?
Any thoughts on this, or motor design would be greatly appreciated. Or if you would point me in the right direction.

Many thanks and best regards.

Tim

FlyerKV
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Re: Please put your "I am new and need help" question here.

Post by FlyerKV » Sat Sep 05, 2009 8:28 pm

Hello all, i'm new here. My name is Alexander and im from serbia. One of my dreams is to make a RC jet car and i hope that you'll help me.
I just studied how valveless pulsejet works, but don't know how the valved one works :\
Here you go some of my questions:
1. Which engine is more powerfull so it can push an RC faster? (i would like to run over 50kmh (20mph) if it's possible)
2. How long does it have to be? (i would like to put a two of them)
3. How to make a gas tank?
4. Can i use an standard LPG gas that normal car uses?

I didn't think about RC's size, it will depend on engine size, and i thought to weld 3mm thick steel bars for whole frame.

Regards

ace_fedde
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Re: Please put your "I am new and need help" question here.

Post by ace_fedde » Sun Sep 06, 2009 10:31 am

Dobar dan Sasa,

On this forum we try to stimulate new members to study the forum. That's exactly what I'm going to do.
All the info that you ask for is pretty easy to find, specially if you use the search button.
I hope though you don't have a internet by phone-line connection, than it might be a problem for you to search the forum :(

Fedde
Your scepticism is fuel for my brain.

FlyerKV
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Re: Please put your "I am new and need help" question here.

Post by FlyerKV » Mon Sep 07, 2009 10:01 am

Ace_fedde, thank you, i'll try to search everything i need.
And, i don't have phone line conection :)

GalFisk
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Re: Please put your "I am new and need help" question here.

Post by GalFisk » Mon Sep 14, 2009 10:31 am

Hi, I'm new :)
I have a couple of 2" 90 degree stainless steel bends and lots of stainless steel sheet, so I'm planning on building a classic Lockwood engine. Can I just take this plan, scale it down to 2/3rds and expect it to work? download/file.php?id=11410
My bends are a bit longer than that those in the plan, does it matter if the total length of the tailpipe gets a bit longer, or should I shorten the conical section to get it to match the plans? I don't know enough about which dimensions are critical and which ones are not.
My sheet metal is 3mm thick, so it may be simpler to weld on an intake pipe flare than to flare out the welded tube. Would a 1" wide strip of sheet metal make a good flare, and would a 45° or 60° angle (or another angle) be better, if it even matters?
Answers are greatly appreciated, I'll probably have more questions as the build progresses. I'm hoping to permanently add pulse jets to my list of fun and interesting hobbies.

metiz
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Re: Please put your "I am new and need help" question here.

Post by metiz » Tue Sep 15, 2009 7:07 pm

I'm not new but I do need some help :P didn't want to start a new thread for this.
What would be the best position for an injector in a 5lb laird chinese engine? .Also, straight or Rossco? Kinda need it to go right firt time around - don't have the luxury to mess around on this one.
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phelim
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Re: Please put your "I am new and need help" question here.

Post by phelim » Thu Nov 05, 2009 9:26 pm

Does anyone know a home-made way of producing a spark for a pulse jet? I'm familiar with the Model T ignition system in USA but I can't get it here. Any help, especially diagrams would be appreciated.

metiz
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Re: Please put your "I am new and need help" question here.

Post by metiz » Thu Nov 05, 2009 9:29 pm

phelim wrote:Does anyone know a home-made way of producing a spark for a pulse jet? I'm familiar with the Model T ignition system in USA but I can't get it here. Any help, especially diagrams would be appreciated.
tossing a simple sparkler in the combustion chamber will get you going without electric ignition
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Mike Everman
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Re: Please put your "I am new and need help" question here.

Post by Mike Everman » Thu Nov 05, 2009 9:35 pm

You can use the spark unit from a home furnace, a clothes drier, or a gas stove.
Mike
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