Posts Tagged ‘pump’


Air Compressors

Our next water rocket car design is coming along nicely and it is already obvious that it will take way too long to pump up the bottles  with just the  hand pump. Getting the three bottles on  MkXI car up to 140+psi pressure takes a lot of effort so a lot more bottles will be a lot harder :( ….. So we  are looking at alternatives.

Here ebay is our friend to find second hand compressors  to try out.

The first compressor is a 12V compressor for 4WD tires. This didnt appear to be an el cheapo one.

Truck Air 275 - 12V Compressor 275psi

This compressor has a small fan to cool the compressor built in and will run from a 12V lighter port. We cut off the normal car tyre connector and fitted a female nitto quick release air hose connector so we could connect it to the high pressure hose and the launcher.

First we tried 1 x 2L bottle with no water and tested how long it would take to get the bottle to 120psi. Unfortunately after about 6min it only managed to get the bottle to 90psi and it cut out a few times in the process. Also its very loud for a small compressor.

Next we tried the 3 bottle stack with again no water. This time the compressor only managed 60psi before it would cut out.

While this might be good for 4WD tires at 35psi, its no good for water rockets ..  We need to crank it up a notch or two ..

Next on the list is to try a stronger air compressor with its own power source for taking to launch sites .. so we managed to find this petrol powered air compressor, again on ebay, again for not very much $$.

Pilot K17P 5.5HP Petrol Powered Dual Piston Compressor

This compressor has been decoupled from its air tank, which is what we wanted, but its still heavy ~40kg. Its in good working condition and the engine and compressor seem to work well.  There is plenty of power in the reliable 5.5HP Honda engine. We are in the process of adding a gauge and quick release coupler plus a manual safety valve, the compressor needs an oil change as well.

It already has a engine cut out which we manually tested and it cuts the engine, just not sure at what pressure yet. There is a air line from the top of the compressor pistons to an air ram connected to the engine throttle.

Air lines from the top of the pistons

Air ram connected to engine cut-out

The compressor is rated at 145psi and it has dual pistons.  It also needs a cage for the flywheel and a set of wheels, but if it gives the pressures we are after then we will add them.

We will post updates after our next series of tests. This compressor isnt for our current car so it wont effect our launch attempts using that car.

Posted by on December 8th, 2010 1 Comment

Updated Launcher – High Pressure Components

Next on the list was upgrading the launcher with metal connectors and high pressure hose.  We upgraded the following

– replaced the gardena quick release on the abort extension hose to a male Nitto connector
– replaced the  first gardena quick release on the launcher with a Nitto Female quick release
– replaced the poly hose on the launcher with high pressure hose (290 psi)
– replaced the poly  90 degree elbow with a metal 90 degree elbow with bards

The abort extension hose was the first to be updated and now all connections are Nitto air hose connectors, the male Nitto connector was added to the end. The barbed section goes into the hose.

Nitto Male Hi Cupla Std 30PH

Added Nitto male to end of abort hose (to connect to launcher)

The brass elbow was fitted into two sections of high pressure hose, one section has a Nitto female connector to connect to the abort extension hose, the other end has a gardena quick release to connect to the rocket nozzle.

90 Degree Brass Elbow with barbed connections

This section effectively converts from air hose connectors to gardena quick release.

High Pressure converter from Nitto Air hose to Gardena connector

We have managed to find a female gardena connector that has a barbed connection on the hose side. This barbed connection goes 30mm down into the hose and ensures there is  more space for the clamp to hold the hose to the  gardena connector.  At the moment there is only about 8mm-10mm of the gardena connector down inside the hose, so there is a chance it might  fly off under high pressure.  We  ordered the barbed one in from our local irrigation supply store, so we will probably replace the one we have on the launcher prior to the next launch with the new one once it comes in.

The high pressure hose and connectors were mounted back on the movable section of the launcher, strapped to the steel rod and screwed down.

High Pressure Hose mounted back on the launcher

All the sections  were connected up for a test and no leaks.  This configuration is upgraded to the high pressure hose and connectors from the pump to the launcher, here is a picture of all the sections connected

All sections of upgraded launch system

This current launch system lets us position the abort valve 5m from the launcher and the pump another 15m back from that if required for high pressure launches and tests. We will do a high pressure test of the hoses and connectors in this configuration without a bottle to ensure the system can hold without any leaks.

Posted by on October 28th, 2010 2 Comments

High Pressure Air Hose – Upgrade (100th Post)

This weekend we have upgraded the air hose on our launcher to the new 290psi (working pressure) air hose.  The air hose had Nitto connectors so we have continued to use these where a connector is needed.

First step was to remove the old coiled air hose and install a Female Nitto quick release to the Air pump hose. The air pump hose has an internal diameter of 8mm, so getting the 10mm barbed section down the middle of the air hose took a little while. Here is the pump with its Nitto quick release installed.

Air Pump with Nitto Quick Release - Closeup

and another pic of the pump

Air Pump with Nitto Quick Release

The Nylex High Pressure Air hose is 15m long and the male end clicks straight into the quick release on the pump.

Pump and Air Hose connected

The next part was to install a male Nitto connector to the abort section of the launcher.

For this we used a small section of the Nylex hose and one of the male Nitto connectors. As the Nylex hose has an internal diameter of 10mm this was relatively easy. The other end of the Nylex hose connects to the abort T piece which has a 12mm barbed section. This took a bit longer to get on, but some hot water and a few expletives later and it was on.

Abort section with Male Nitto connector

The male Nitto connector on the abort section clicks into the female quick release of the 15m air hose.

15m Air hose and Abort section connected

The Gardena quick release is still used to connect to the launcher itself. We will probably upgrade this in the near future now we know the 10mm hose will fit over a 12mm barb. We will also be replacing the plastic release valve with a metal one and increasing the length of hose from the release valve to the launcher.

The Gardena uses standard 12mm fittings, whereas the air hose use a standard 10mm fittings, so there needs to be a conversion at some point. Here is a pic of the pump and abort section all connected.

New Airhose - all connected

A quick test today up to 100psi showed no leaks, we will do a higher pressure test prior to the next launch day.

Also a small milestone, its  our 100th posting on the HHWRSA website and our 2 year anniversary of HHWRSA :)

Posted by on July 18th, 2010 Comments Off

New Hand Pump

After the demise of our foot pump at the last launch day, we needed to get a new one. We decided to look for something that would reliably pressurize to 130-150psi. After looking at 12V compressor options we have initially settled on a hand pump. We took delivery today of a TOPEAK Joe Blow Ace Bike pump.

This pump has 2 pressure chambers and a switch on the top which can be set at 60psi, 120psi or 200psi. In the different configurations it switches between the chambers to allow a lot of volume on the low pressure selector or a small volume but high pressure when choosing the high pressure selector. This should allow us to pressure up to 60psi quickly, then switch to the 120psi selector to get the pressure up from there.

The pump has 2 foot rests, a hand rail, the pressure selector switch, 2 long pressure cylinders, about a 1 m hose (looks like 6mm or 8mm) and a pressure gauge up to 260psi.

Here are some pics of the pump.

TOPEAK Joe Blow Ace Pump

TOPEAK Joe Blow Ace Pump - Side View

Front View

Front View

Pressure Selector Switch

Pressure Selector Switch

Pressure Gauge

Pressure Gauge

The unit is surprisingly big, standing at approx 70cm high and when the handle is fully extended goes up to about 1.4m. Here is a pic with the handle extended, you can see both cylinder pumps clearly

Handle Extended

Handle Extended

Posted by on October 25th, 2008 9 Comments