Air Command Water Rockets Flight Log - Day 164

Each flight log entry usually represents a launch or test day, and describes the events that took place.
Click on an image to view a larger image, and click the browser's BACK button to return back to the page.

Day 164 - Liquid Density Experiment - Part 1

Date: 29th August 2015
Location: Whalan Reserve, NSW, Australia
Conditions: Calm to light breeze ~5km/h, sunny 21C,
Team Members at Event: GK and Paul K.

Liquid Density Preliminary Experiment - Part 1

This week we performed a preliminary experiment that we plan on carrying out next week. A common question we get asked all the time is if there is something that can be added to the water to produce more thrust. Since Paul also had to choose a science experiment to do at school, we decided to combine the two and take this launch opportunity to do a trial run to see if we could detect a difference as simulators predicted that the difference was going to be small. In this experiment we wanted to compare a denser liquid to water alone.

Please see Day 165 for a full write-up of the liquid density experiment.

For the denser liquid we made up a sugar solution by putting 700g of sugar into a jug and then added warm water until we had 1100mL of solution. The density turned out to be 1.25 g/cm^3

For the rocket itself we decided to use a single bottle rocket as that represented the typical rocket kids fly in school projects. We just put our regular fins and nosecone on it as the ultimate altitude didn't matter because it was going to be a relative comparison.

Rocket Parameters

Parameter	Value
Weight	280 grams
Capacity	1.3L (measured)
Diameter	90mm
Nozzle	9mm
Launch Pressure	120psi
Liquid Amount	450mL

Results

Following is a table of all the flights and their recorded altitudes. We alternated the solutions to try to eliminate any changing environmental conditions.

Flight #	Fuel	Altitude (feet)	Comments
1	Water	180	Good flight
2	Sugar	177	Good flight
3	Water	175	Good flight
4	Sugar	176	Good flight
5	Water	180	Good flight
6	Sugar	173	not-quite-vertical flight
7	Water	183	Good flight
8	Sugar	-	self launch invalid data
9	Sugar	194	Good flight
10	Water	182	Good flight
11	Sugar	171	not-quite-vertical flight
12	Water	183	Good flight
13	Air	54	Late deploy and crash

Here is a graph of the flights grouped by fuel.

From this experiment we can see that there is only a slight difference between the performance of the two densities, although when you average the altitudes for each fuel we can see that on average the denser liquid performed worse. The water reached an averaged altitude of 180.5 feet and the sugar solution reached 178.2 feet. Although there was one sugar flight that reached 194 feet which looked out of place with the other flights. If this flight was removed from the calculation then the average would have been closer to 174 feet. The water flights were quite consistent. The difference here is close to the 3 feet difference the simulator predicted.

We will perform this experiment again to see if it also gives similar results and we will also try alcohol as a lower density liquid to compare against.

Here are some images from the experiment:

We also learned from the experiment that the sugar solution makes everything very sticky, though it was easily cleaned up with fresh water. I am sure the ants had a field day ... mana from heaven?

Go to Part 2 of the Experiment

Other Flights

Other than the experiment flights, we also flew a number of other rockets at the launch. Throughout the day we flew a total of 3 Axion II's with foam which are always fun to watch. Paul also launched his Pod 2 rocket and recovered it safely. He's been flying this rocket for quite a few years now and it always performs well.

While performing the density experiments we were asked how much of a difference the water makes to the flight of the rocket, so when we finished the experiment we launched the small rocket with air only. The rocket only went up to 54 feet, before tipping over and crashing just as the parachute was coming out. No serious damage was done though. This was significantly lower than I expected, but the rocket was slightly on the heavy side.

Flight Details

Launch

Details

Rocket		Pod 2
Motor		C6-5
Payload		None
Altitude / Time		? / ? seconds
Notes		Good launch, and good recovery.

Rocket		Axion II
Pressure		120psi
Nozzle		9mm
Water		1400mL
Flight Computer		ST II - 5 seconds
Payload		None
Altitude / Time		? feet / ? seconds
Notes		Good flight and good landing,

Rocket		Axion II
Pressure		120psi
Nozzle		9mm
Water		1400mL
Flight Computer		ST II - 5 seconds
Payload		None
Altitude / Time		? feet / ? seconds
Notes		Good flight and good landing,

Rocket		Axion II
Pressure		120psi
Nozzle		9mm
Water		1400mL
Flight Computer		ST II - 5 seconds
Payload		None
Altitude / Time		? feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - water
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		180 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - sugar
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		177 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - water
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		175 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - sugar
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		176 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - water
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		180 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - sugar
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		173 feet / ? seconds
Notes		Good flight and good landing, Not quite vertical.

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - sugar
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		? feet / ? seconds
Notes		Self launch and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - sugar
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		194 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - water
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		182 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - sugar
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		171 feet / ? seconds
Notes		Good flight and good landing, Not quite vertical.

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		450mL - water
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		183 feet / ? seconds
Notes		Good flight and good landing,

Rocket		Exo-1
Pressure		120psi
Nozzle		9mm
Water		0mL - air only
Flight Computer		ST II - 3 seconds
Payload		AltimeterOne
Altitude / Time		54 feet / ? seconds
Notes		Late deploy and crash.

<< Previous Back to Top Next >>