A rocket maker

[skydelph]

Hello,

I’ve been working with rocket engine technologies several recent years as a technical expert.
This brought me inspiration and determination to make a rocket by myself, starting from engine selection to full design.
As usual, the first step would be the purpose of the system. It should be a low range rocket as a trial.
Does anyone know is it simple to become such a rocket maker or any permissions are necessary?

Thank you.

 

[nemoc]

Hi Skydelph, I see you're in the United Kingdom so I don't know what you may need in the way of permission. I would start by looking for and joining a local rocket club. Here is a link to one of the organizations that has members all over the world. Home - Tripoli Rocketry Association I hope this helps.

Craig

 

[Rocket Man]

I have been building rocket engines for about 50 years. You can build solid fuel and liquid fuel engines. Learn about fuel jets and fuel mixtures then build a small engine with no cooling system you can fire them for 5 or 6 seconds with no melt down. I build a few engines to run on propane & oxygen they are easy because you can use the tank regulators to get perfect fuel oxygen mixtures. I once fire off an engine attached to a work bench the work bench took off out the big garage door and across the parking lot we ran and jumped on the work bench to stop it from leaving town. LOL. You can build low power engines with 1 part baking soda & 7 parts vinegar. Baking soda needs to be dissolved in water so you have 2 liquids to spray into the engine. For higher power engines use 40% muriatic acid and sodium hydroxide dissolved in water this engine produces an amazing about of instant steam power, no flames. There is a world record race car that uses a 2000 psi water it blows 100 gallons of water out of the rocket engine in about 7 seconds video of it is on YouTube. I use to make sold fuel engines that would travel 4 miles in about 20 seconds. If you get really serious build some liquid fuel & oxygen engines with a cooling system. Pulse jet engines are very simple and easy to build and run excellent on propane. Did you ever have a class with a lab where you read 1 chapter then do experiments in the lab to learn how it works.. Go online to, Abe Books, look for this book or other book with good pictures. Some books are easier reading than others. There are good fuel jet videos on YouTube.

 

[awake]

I have no idea how he stacks up in the "serious" rocket building world, but I enjoy watching Integza's videos on YouTube - he is always trying to come up with some way to build a rocket using 3d printed parts.

 

[SPOTTER]

There is this book, the most complete guide to the pulse jet

 

[mike-oz]

Have built a pulse jet but we are yet to get it to run. How critical are the proportions?

Great fun but

P.S Don't ask where we live!!!

Would love to build a simple straight thru version using something other than propane - any suggestions?

 

[mike-oz]

There is this book, the most complete guide to the pulse jet

Is it available in English

 

[SPOTTER]

I do not know ,

 

[Steamchick]

Mike-Oz: Yes, VERY critical! - or so I understand from what I have read.
Make a Pulse Jet Engine, (Scanned From 1958 Plans) : 17 Steps - Instructables
BIG PULSE JET PROJECT - COLINFURZE

Enjoy!
K2

 

[Rocket Man]

Have built a pulse jet but we are yet to get it to run. How critical are the proportions?


Combustion chamber length is 2 times the inside diameter.

Tapered cone is same length as combustion chamber.

Exhaust pipe cross sectional area is 50% less than combustion chamber cross section area.

Total length of the engine from air intake valves to exhaust pipe tip end determines engine run frequency. Length is 13 times exhaust tube inside diameter.

Air intake cross sectional area 60% of the combustion chamber cross sectional area.

This engine has compression ratio 2 : 1 from combustion chamber to exhaust pipe, easy to start at 25% thrust. Throttle it up to 99% thrust.

Forward speed ram air makes engine run lean fuel can be increased for more thrust. At 400 mph ram air allows fuel to be increased as much as it takes to produce more thrust and more speed to 99% throttle. Ram air at 400 mph can make 5 lbs of thrust increase to 20 lbs of thrust.

Pulse jet engines will run a tiny bit rich but not lean. If you try to run engine past 100% throttle it will run too lean flame out and stop running.

Reed Valves are .008" thick spring steel or stainless steel. Valve width 10mm or 3/8" wide. Length is long enough so engine vacuum can suck them open. I used a fish hook, string, & tiny weights to learn now much it it takes to open reed valves 3/16". Valve length about 1¼" long for small 5 lb trust engine. If valves are too short engine will try to start but never run. If valves are too long engine will start easy and run until valves break off. Valve need to open & close like a rocking chair smooth rocking motion then engine will run for a week none stop no problems.

Propane is excellent fuel engine starts easy at 25% throttle. 4 gallons of gas with 10% alcohol mixed with 1 gallon of diesel is good fuel to use after engine starts on propane.

Spark plug location is usually best about 3/4 of the way to the rear of combustion chamber.

Best fuel inject I have found sprays fuel forward at the center of the reed valves inside the combustion chamber.

I can't remember who said, a pulse jet engine is the simplest most complicated engine ever invented.

AdeBooks.com



Great fun but

P.S Don't ask where we live!!!

Would love to build a simple straight thru version using something other than propane - any suggestions?

View attachment 135295

 

[Ozwes007]

Pulse jets use pressure waves to run effectively, so divergent angles, lengths etc are reasonably critical. However most will run if made at least half decently. They won’t run efficiently or produce maximum thrust though.

 

[Steamchick]

If you can tolerate watching this stupid guy....

K2

 

[WisJim]

I remember the rocketry craze after the Soviets launched the first Sputnick back in 1957. My dad was a high school chemistry and physics teacher in a small high school and his science club members built some rockets. I was in grade school but got included in the projects. I remember them building small rockets fueled with powdered zinc and sulfur mixture and some other powdered chemical mixes. The rockets were lengths of iron pipe with sheet metal fins welded or brazed on and nozzles made of washers. They would launch them at night in a farm hay field and it was a wonder that no one was injured and that the used rockets were always found. No one else involved in project is still around to ask about it and my memories of it are a little sketchy.
Regarding pulse jets, my youngest son (now 40) has one sitting in my shed that he built a few years ago. It's propane fueled and is bolted to a sheet of plywood and was mostly used to ignite bonfires and impress folks with a big flame. Never was installed on anything.

 

[Steamchick]

I wonder.... if a pulse jet exhaust was fed into a turbine, could the pressure pulsations be a more efficient way of converting the heat into useful power? E.g. to drive a generator? Car and truck turbos are mounted adjacent to the exhaust manifold to capture energy from the exhaust pulsations (shock waves), not the gas flow.
K2

 

[Ozwes007]

You could fit a sleeve around the unit and superheat water to drive a steam turbine. Cooling and circulating the water would be interesting

 

[mike-oz]

I remember the rocketry craze after the Soviets launched the first Sputnick back in 1957. My dad was a high school chemistry and physics teacher in a small high school and his science club members built some rockets. I was in grade school but got included in the projects. I remember them building small rockets fueled with powdered zinc and sulfur mixture and some other powdered chemical mixes. The rockets were lengths of iron pipe with sheet metal fins welded or brazed on and nozzles made of washers. They would launch them at night in a farm hay field and it was a wonder that no one was injured and that the used rockets were always found. No one else involved in project is still around to ask about it and my memories of it are a little sketchy.
Regarding pulse jets, my youngest son (now 40) has one sitting in my shed that he built a few years ago. It's propane fueled and is bolted to a sheet of plywood and was mostly used to ignite bonfires and impress folks with a big flame. Never was installed on anything.

Love the seat of the pants, can do attitude. Way too many rules and regulations today (particularly in Australia, keeping the BOYS in a job), as you say "no one was injured" maybe because then we all looked after our own health and safety instead of big brother dictating?

I wonder if there are still plans around that your physics teacher Dad used? But the chemicals are probably on the restricted list now :-( particularly here.

Cannot even keep making my own cheese in Oz because raw milk is now illegal to buy.

 

[Steamchick]

Ozwes007: Sorry, but you missed the point I was making - sorry if I wasn't clear with my suggestion! To simply use this as a big burner to make steam would be wasting the energy from pressure waves (Noise), which is what I am trying to capture (and what the pulse jet does in huge amounts!). The heat energy could be generated more efficiently, for a steam boiler, by a simple burner than by having a long tube and using resonance to pressurise the air before combustion. While that higher combustion pressure in the pulse jet will create a higher combustion temperature, by the time it has passed out of the exhaust it has expanded and cooled to the equivalent of a simple blow-lamp flame anyway. (Which is what you see with the blue cone of flame from the exhaust!). A correctly matched turbine (as in a car or truck turbo power fan) is designed to take the pressure waves that hit the blades, and extract the impulse energy, as well as soaking up power from the mean gas velocity powering the blades.
Consider a Tesla Turbine powered by an air supply from the tank on your compressor. The pressure is converted to gas velocity in the jet cone, which then drags the discs around at the sonic speed of the jet of gas.
Conversely, in the car/truck turbo, the turbine sees a pulsation of very high pressure (exhaust valve opening pressure pulse at a few bar) with a wave form leading to a near vacuum (towards or after the exhaust valve closing point). The peak pressure energy is transformed into mechanical power as the pressure wave hits the blades, and some more power is extracted by aerofoil effects of the velocity of the exhaust gas flowing over the curved blades, and the turbine spins freely when there is no exhaust gas passing or a near vacuum "negative pressure" part of the pressure wave passing through. I understand the pressure pulses provide the major part of the power extracted by the turbine. On an ICE, the turbocharger has to cope with tremendous variation of exhaust gas pressure volume and temperature. But the turbine designed for a pulse-jet could be tuned to maximum efficiency at a certain speed associated with the natural frequency of the pulse-jet. Thus maximising the turbine efficiency, say for powering an alternator?
Just idle thoughts from an idle person...
K2

 

[Steamchick]

mike-oz: I won't mention the chemicals you can buy and use... because in the UK computer messages are monitored for the names of the chemicals - in case anyone is making &ombs or rockets for mischievous purposes.
But most chemicals are available - and some beneath your kitchen sink already! Some chemicals are used on your garden to make things grow, or die. It is the recipe that really makes the difference: and the sizes of packaging are critical: Combustion speed (gas generation speed) versus orifice size is critical against the mix of chemicals. - At one end of the scale the pretty flame of a firework, or just at the right point you have a rocket engine, but just past that a &omb! You'll find some info if you really want to search the web...
Have you ever thought why rocket development always takes place a long way from people - who hide in &omb-proof bunkers?
https://www.bing.com/videos/search?...59C81E1F20BAAEBB42E859C81E1F20BAAEB&FORM=VIREK2

 

[awake]

Cannot even keep making my own cheese in Oz because raw milk is now illegal to buy.

Mike, I've been making cheese for many years here in a part of the USA where raw milk cannot be sold - I just use store-bought pasteurized milk. The key is to avoid ultra-pasteurized milk; that won't work at all. But "normal" pasteurized milk can work. Mind you, it performs much less well than raw; your curds will not be strong, no matter what you do; but I've successfully made > 100 cheeses of a wide variety.

 

[Steamchick]

Aha! I see the reference to rocket fuel. Some cheeses have a "rocket" effect on me. I.E. They are discharged at high velocity. But I enjoy eating most cheeses. Favourite is a very mature cheddar. But I do enjoy a Stilton, or other good blue, or a French cheese like La Liverot.
K2