Air Powered Rockets

[mbauer]

Many years ago on this forum I meet Yogi, who passed away. (Retired-for-Now) when I posted a thread about my paper rockets and a bellows type of launcher.

He introduced me to the stomp rockets using the soda bottle. We emailed back and forth conspiring on many projects.

I have several Stomp Rocket designs. Rockets as well as winged fighter jets. One time launched Robert Goddard's first liquid fuel design.

Then on a website, Steve Sprangler, found the design for an air tank made from PVC.

I built a couple. The first was made using 2" diameter PVC in an U shape. It worked great but took up major floor space.

Next stage found me on line using pipe volume calculators to determine just how much volume the Air System plumbing had. Wanting to use 4" PVC to make a single tank with enough volume to power the biggest rockets, and have a reserve of air left over even after the rocket tube included at the end of the launch barrel was added in for total length/volume.

Soon after the plans for the PVC tank were removed: It was a very dangerous design. If not made properly it can explode throwing PVC shrapnel everywhere.

My 4" version is encased in a welding fiberglass fire blanket wired shut to protect from this problem.

Still: No more Air Tank launches in years because of the danger.

The other day I finalized an air tank design for my purposes. Launching rockets using Estes type power is expensive! Air can be re-supplied with a bicycle pump if needed.

My last testing with air soon brought up a quick issue: How to deploy a parachute?

I came up with an answer that should work for deployment. The rocket will be slightly lighter when this deployment feature is added.

Then I came up with a really cool way for deployment in all rockets: AirBlast!

What is an Airblast Deployment System?

Well it uses a balloon and electricity or a fuse to deploy.

R/C using a starter like wire with nichrome wire heating a filled balloon is one way to get the blast of air! Won't have to use black powder any more.

The other version is a timed fuse deployment. I have some slow burning fuse used to de-thermal free flight gliders so they can return to earth.

Count down becomes critical for this version. Know the fuse burns for 30-seconds at a specific length, want a 5-second delay after lift-off? Need to do the math and coordinate last 10-seconds of countdown to give the 5-seconds of flight needed. 6-now becomes 0 for launch purposes.

Can hardly wait to find out how this method is going to work.

Oh, the Air Tank? Whole new design using schedule 40 6" steel pipe and 1-1/2" schedule 40 pipe/fittings with a 1/4 turn ball valve, rope pull system to launch.

Refills will be a welding nitrogen compressed gas cylinder. Quick refills and the pressure can be regulated with the regulator on the cylinder. My tank should be able to with stand 285psi, but max I will ever use will be 125psi, if a way can be found to make the internal psi tube stronger in the rockets. Yes, there are ways!


Will be the only one like it, but will allow cheaper testing of my rockets. They will soon be huge, these mid range ones are okay, but really want some big versions....

Mike

[surfduke]

i AM VERY INTERESTED IN UPDATES ON YOUR ENDEAVORS.


THANKS FOR SHARING YOU INFORMATION.

[mbauer]

Originally Posted by surfduke

i AM VERY INTERESTED IN UPDATES ON YOUR ENDEAVORS.


THANKS FOR SHARING YOU INFORMATION.

Hi Surfduke,

Thank you.

Was in contact with Estes about the ejection charge, have many questions. Because of liability they would only answer certain ones and then very vaguely at that. One answer was to downsize the ejection tube to maintain the pressure.

Really don't want a ballistic landing pattern, was hoping to find out if the charge can lift certain weights. Understand that those weights might have added air friction from speed to also overcome.

Knowing that their rockets really aren't that tall, just how much force is available to eject the capsule and deploy the chute once the charge reaches the end of my rocket ejection tube? Some are over 5ft long.

Been thinking on this issue while building. Not going to downsize. On the Ye Olde Rocket site someone said to use a helium balloon to help lose weight.

This isn't practical, it would need filled each time to launch, helium is very expensive now. The Balloon would pinch the ejection tube or could it distort the rocket shape? Would need a big balloon to get any benefit. The other day, was thinking about this idea and bam-why not try to eject the capsule.

One of my next rockets will use the Estes ejection charge to send a shuttle up the tube to pop the balloon with a thumbtack. The balloon will be held in place with a plastic anti-bird net velcro'd into position. Cones will direct the AirBlast upwards towards the capsule.

Nothing has been tested yet, probably lots of things to work out, but drawing up plans and a valid test program to verify different types of balloons.

Have a welding airflow gauge for testing welding gas flow, going to build a sealed box to explode the balloons in. Simple port with the flow gauge should give a basic understanding of flow and velocity.

Not sure how big of balloon to get, plan to get a few sizes for testing.

Printed a full size ARCAS. Once it is done will be working on the AirBlast ejection system.

ARCAS build will go fast. Only three sheets of 24x40 cardstock, small diameter for the 9ft height-Diameter: 4.5". Have some really awesome photos of real ones, data with serial numbers are also a reference. Something this lite weight probably a 29MM E16-8 should give good performance.

Because of the boat tail, this will change how internal parts are installed.

Cutting parts out tonight, probably ready to fly next weekend.

The anti-bird netting will stop the balloon parts from becoming litter. If this works, then wadding needed will also stop being a litter issue. Have built Estes models with different ejection methods. The F14 Tomcat was one. Know that to control the shuttle just need to vent the tube and the pressure goes away. Shuttle will be suspended about 1/2" from bottom of the balloon. Two large vent holes will be slightly above the shuttle to get rid of the pressure once it flys up, pops, the balloon and is forced back onto the original roost when the balloon does it thing. Shuttle will have a stop to keep it in the tube.

Mike

[mbauer]

Have some really old videos of the Air Powered Rockets.

No scale just 6ft tall-Saturn V want to be: 6ft Saturn V Flying-30ft.AVI - YouTube

Mercury Redstone 1/12 Scale: 1-12 scale Mercury Redstone 80-psi Air Launch.AVI - YouTube

Those were at 80psi. Trying 90psi:
Paper Cardstock Saturn V go Bang-90 lbs launch air pressure.AVI - YouTube
Saturn V BANG.AVI - YouTube

Know that the cardstock tubes I make can handle 80psi but not 90psi. Found ways to make them stronger.

Mike

[mbauer]

Parts are at the weld shop.

Using 4.5" Dia Schedule 40 pipe with pipe caps to create a 225lb PSI rated pressure chamber.

Hydrotesting with stamp will be done.

Plan is to use a 40 cubic foot size Nitrogen Cylinder (2000+ Lbs PSI) to fill the chamber to 150psi using a regulator to get each fill the same.

A 9-ft long rocket and the launch barrel are less than 3-liter in size. My whole system is designed for 3-liters but at 150PSI. Should send my rockets to new heights.

Using an internal Rocket PSI tube to handle the 150psi. The tube is normal rocket body tubes glued end to end instead of rolled into a tube shape cardstock.

Cardstock tubes failed at 90lbs PSI for the big heavy rockets and 94lbs PSI for a long thin light weight one.

These internal rocket tubes hopefully will allow 150psi launch pressures through a 3/4" diameter tube. My over 9ft long ARCAS rocket weighs less than a 1lb, not yet ready to fly.

Limit on system is the regulator output. 150PSI maximum, unless really want to spend some serious cash to get higher output regulators. 225PSI hydro test will give a safe operating PSI of 160PSI.

Looking at parachute deployment systems. Interesting stuff on the market. Dual deploy means needs the charge off of an Estes engine to blast the chute out, then it opens at a pre-determined altitude. $129. Or same capability but option to do something else like air start an engine $141.

Trying to change-fit both an Air PSI tube and then convert insides to equivalent size Estes rocket engine to see which goes higher. ARACS full scale 1/1 is perfect for this idea maybe to work. Since both use same size internal PSI tube, should be able to slide in and out if internal formers are glued to rocket shell.

Lots of experimenting going on. Once the pressure chamber is done, plenty more to do. 10ft tall 1/32 scale Saturn V might fly after all.

Mike

[mbauer]

Been super busy this rainy summer. We are having 5-days now of sun.

I have some updated photos of my new air tank.

500lbs of air pressure safe. Will only launch with a maximum pressure of 150# PSI due to limit of regulator being used to fill.

Front side Showing pressure gauge


Back Side Showing Valves


Back side with description of valves


Still have the tank holder to make before first launch.

STOMP Rockets taken to a new level!

Mike

[mbauer]

The air tank system is almost complete. Probably round some of the sharp corners off with a grinder once the following two things are complete.

A few items still to add before painting will be the following:
1) 1/4" x 3" pipe nipple for a small USA flag that will be added for wind direction indicator
2) Tool holder for my screwdriver style Nut Driver

Launch base is detachable. Tank is hose clamped to the base. Winds can be compensated for by loosing the hose clamps and rotating the barrel to point into the wind.

Note that some of the photos show the base sitting on top of the ground. Then I hammered the base into the ground to anchor it. Two 3" angle iron are the Base pad/ anchors.

Bought some cheap pulleys from Home Depot and welded an adjusted chain link to one of them. Tying the rope to the chain link anchors the rope, the other end loops through the pulley on the 1/4 turn ball valve handle.

Pulling the loose end of the rope opens the valve with very little pull. Hoping a two year old can pull with ease, reason for the pulleys. It works with the tank 90 degree from vertical as well as the vertical.

Rocketry rules say you must stay at least 15ft away from the rocket when launching, I have 100ft of rope.....

Photos:
Tank Front


Tank Back


Test Rocket is Loaded and ready to pressure up


Angle Anchors not hammered in yet


Rope Pulley Launch system


Anchors hammered into ground to stabilize


Pressuring up with a bike pump for testing


65lbs of air pressure (inner scale)


Windy but the rocket flew fine!

Have altimeter that allows a dual deploy, I plan to add a balloon inside the bigger rockets to pop using the deployment aspect of the altimeter to heat a nichrome wire, which should pop the balloon to deploy the chute.

Mike

[mbauer]

Found a hand powered Air Pump that can supply 4500PSI!


Should be here by the time I finish a rocket designed for the new air tank.

They have a 110-120V AC powered and it also runs off a car 12V system. It supplies 4500PSI as well.

Figure to test everything with the Hand Pump, get active enough might purchased the electric powered one.

Check this out:
Photo of launch below.


Homebrew Air Powered Howitzer Rocket Launcher: Homebrew Rocket Howitzer | Gotta love a photography challeng… | Flickr

1000 ft/sec = 681.8182mph in 0.25 seconds. Curious about any rocket motors that can match Air Power?

Would be interesting to use an air start at the end of the coast phase from the air power.

Knew about this years ago, finally found the site again. All this from a photography challenge...

Mike

[mbauer]

Tonight I will be working on a full size nosecone, upper fuselage shell and the altimeter to do a ground test of AirBlast Deployment System.

Purchased a Missile Works RRC3 Altimeter and parachute deployment device.

Sent an email requesting how to a ground test. Sure glad the reply was quick on how to test the circuit on the ground.

Altimeter has to ascend above 200ft to activate the deployment circuit. The actual altitude it will deploy the parachute at is adjustable. 100ft above the ground is the lowest setting.

The reply from Missile Works mentioned the circuit only supplies 2-3Amps for short duration.

Will this be enough to heat the nichrome wire and pop the balloon? One way to find out!

Where I have to mount the altimeter at is going to be the very bottom of the rocket. The Cat-5 wires will need to travel the whole length of the rocket body.

The balloon will sit in an inverted cone at the very top of the fuselage shell. Once it pops, the escaping air should be directed towards the Nosecone, lifting it off of the rocket allowing the parachute to deploy. I hope.

Will make the mount for the altimeter from some really thin plywood (1/16inch thick), mount the altimeter and 9volt battery to it. Cut some of the Cat-5 wire to length, solder a very thin diameter nichrome wire as a bridge between the two CAT-5 wires.

Once these chores have been completed, time to make the mock up of the rocket nosecone/body. Install some 1/4' opening size bird netting (the kind of netting you use to keep birds away from my blueberry plants) to stop the balloon from becoming litter.

Sure glad the email reply mentioned how to do the ground test; other option could get really interesting...Flying the system above the 200ft activation altitude in my airplane, then descending to the deployment altitude. Hot wire, balloon popping; possibly catching on fire in the cockpit of the Airplane-No thanks....

Photos of the Altimeter:


Altimeter, inflated 5" balloon and pack of balloons:


If this doesn't work, using the air tank above to power a 5" water balloon canon is another project option.

Mike