@Spoif- we too were surprised at the difference. We are not sure how foam performs in other rocket configurations yet, but from further flights this weekend for this rocket we keep seeing the same repeatable results.
You guys should add a parachute to the front for more stable landings cause with the one on the back causes the rocket to turn and dive in unwanted directions
CartUniverse pro gamer We try to aim at landing the rocket sideways as often as possible to reduce the damage to the rocket on landing. Landing the rocket on its fins can break them off.
AirCommandRockets I don't know the altitudes because I unfortunally don't have a altimeter. But It looked like the launchtube and foam combination worked best. Maybe you can try that as well next time? 9mm nozzle and launchtube and 22mm nozzle and launchtube too? Would be nice to see how much a launchtube helps! Olivier
Hello Air Command, very interesting results with the foam. Even when not using the Jet-Foaming Spacer you get great a great increase in Altitude. Over the summer (once School has finished and I have more time!) we will try adding foam and post a video to see if we have the same effect :) Are you going to add foam to the boosters of the Polaron G2 or just the main stage??
Hi Jamie, That would be great to see how foam behaves in other rocket configurations. You need to make foam in the rocket either by shaking it up before flight/during pressurisation, or during flight like with Jet foaming. Simply adding the solution to the water won't do much. You have to get a significant amount of foam leaving the nozzle. Currently I am thinking that we will only add the foam to the main stage. We really don't have a way to make foam before launch in the boosters.
Why does the hight increases if you increas the nossle area? Of course the rocket gets rid of the energy much faster. And that causes a higher Speed - > higher altitued. But here the air resistent is much higher. With a smaler nossle the Energie is provided over a longer time and the end Speed not so high. But the top Speed is reached at a higher altitued. And the lover Speed means not so much air resistance. But still the rockets with a bigger nozzles fly higher. Why is that?
That's a good question, the amount of stored energy is the same in both cases, and you are correct in terms of how drag affects the rocket due to the different speeds. I am not completely sure why they are slightly different, but it may come down to the efficiency of the nozzle. A narrower nozzle will be less efficient than a wider nozzle.
@@AirCommandRockets Yes the funny thing is that i tried to write an altitude calc. for water rockets. That would help me to understand the relationsships between pressure, nozzle size and the amount of water you would need at spezific pressure with specific nozzles. I already built these for normal rockets without Differential equation .It is like a step by step calculation.(with respect to the change of mass, air resestance and thurst). But for water rocket i couldnt manage that. And i strugglet exact at the point you faced above. For the specific change of velocity (from the water rocket) in a periode of time you need a specific amount of Energy. This energy comes from the kenetic energy of the water (Offcourse all that energy in that timestep). The kenetic energy (from the water) is calculatet with the mass and the velocity. And thats the point were i stuck because the velocity is calculated from the accaleration (That is easy) over a specific amount of time (distance of acceleration). But what is this distance ??? And would it change change if you would use a straigt pipe instat of a bottle I think the main question is: From where to where gets the water accelarated. (And does it change if you use a straight pipe or sth. else) I think that is a really interrasting point to improve efficecy by a lot. Im sorry for all the grammer mistakes because i´m just from a german high school.
What would happen if you added your extension tube to the rocket with the 22mm nozzle? Would having the second stage give you more height or is it better to have one stage
Very nice onboard on that 22mm flight, so stable and so fast! Do you know why the rockets go way higher with foam? I think i'm gonna use it on my next flights as well. I am very happy that you guys tested this keep up the good work, as always ;)
Hi Basrockets. We're not exactly sure yet, we're trying to determine what the underlying cause is. I suspect it may be that the foam is exiting at a significantly higher velocity than water. Water is heavy but it also comes out slowly and air comes out quickly but is also light. Foam probably sits somewhere in the middle of those - higher density than air, but higher speed than water. We did another test this weekend where we had the bubble bath dissolved in the water, but there was very little foam in the rocket at the time of launch. The rocket flew to the same height as a water only launch. When we mixed up the foam in the rocket so there was a lot of foam in the rocket before launch, then it flew higher again. If you get a chance to fly some comparison flights between water and foam, I'd love to hear about your results. We are not using the jet foaming spacer for these tests.
AirCommandRockets on my channel I've made a slow motion video from the launches with foam and without, even with a small launch tube. I think the foam takes up more space just when it exits the nozzle, so the rocket can push it self of harder. it probably helps as well that it acts as if there is more water in the rocket but without taking up more space. Do you know how to simulate a flight with foam?
AirCommandRockets Thanks for the big explanation on that rocket i see that you use a tornado tube. Do you think the foam will work the same way without a tornado tube? The rocket that i make is one big pressure chamber and no tornado tube of robinson couping, so i have to test if foam effects the results on my rockets as well.
Basrockets That's a good question. I think it will still work without the tornado tube as long as there are lots of bubbles above the water. It will be interesting to see the results.
Oli4vn That's a cool video. :) Do you have any performance data on how the rocket flew in the different configurations? We currently don't have a way to simulate foam flights. I haven't seen any simulators yet that take it into account. I think in order to simulate it you would need to take into consideration the foam density, which may be a little more difficult to estimate.
I think this is caused by the foam expanding like the exhaust gases in a conventional combustion rocket engine. Adding a bell type nozzel might improve performance even more. en.m.wikipedia.org/wiki/Rocket_engine_nozzle
Could it have something to do with aerodynamic pressure? I dont know the speeds involved, but it seems quite fast, enough to make air resistance a factor. Foam seems to last longer than just water, maybe the water one is flying too fast and hence encountering more resistance, hence wasting more energy?
+ComandanteJ I think that is a part of it. Foam produces about 2/3 the average thrust of water alone, but it gives you about twice the "burn" time. The upshot is that the rocket's peak velocity is lower and with drag being proportional to the square of the velocity, the rocket experiences less drag.
AirCommandRockets It's hardly rocket science. Oh wait... LOL BTW, absolutely love your channel, i wish some day i'll have the time to get into it, and go from Kerbal Space Program and Orbiter to real rocketry, hehe.
Wery interesting. Why do foam increase high of flight? I had observed similar effect with concentrated solution of potassium carbonate. It`s density in 1,5 times more, than density of pure water.
I've watched several of your experiments using foam as propellant. I see the results but I don't fully understand why foam increases altitude performance. Have I missed an explanatory video?
Good question. We also don't know exactly the reason why foam is better. I suspect it has higher nozzle exit velocity. The rocket also doesn't travel as fast so it reduces the peak induced drag. (drag being proportional to the square of the velocity) Although the average thrust is lower than with water alone, it does double the amount of time that thrust is produced.
Hi Michael it's mostly just for fun. The plan is to use the foam in some of the bigger rocket sustainers. We really enjoy watching the long slow burns, and the foam helps deliver that. :)
We believe that it's due to the exit velocity. Although the mass being ejected is less dense than water, it has a significantly higher velocity, and hence more thrust.
This is a good question. The liquid density does play a part in how much thrust is produced. The problem is when you make the liquid denser, although you get greater thrust, you also have a greater mass to lift with that thrust. The heavier mass is the result of the heavier liquid still in the rocket. A liquid of lower density than water will actually perform better than water. The other way to increase thrust is to increase the exit velocity of the mass you are ejecting, and that is what we believe is happening here with the foam. Here is another comparison we did recently that compares the same rocket at the same pressure with the same liquid mixture (same density) except one has been shaken up to form foam and the other one is just the solution. You can see that the foam rocket goes significantly higher. Day145 Water Rocket Highlights Some further reading: www.aircommandrockets.com/water.htm
Great comparison! =) I didn´t thought that the difference is so big. The problem with foam in Germany is that it´s kind of illegal, because it destroys the ground of the fields. Greetings from germany
Hi Raketfued, we too were surprised at the difference with the foam. Interesting that the foam is illegal in Germany, I wonder if you guys have different stuff? The foam we use is biodegradable.
AirCommandRockets There is no law in Germany which says: Water rockets with foam are illegal, but it could be that some farmers take proceedings against the foam-launches, if we use it. Biodegradable foam is a good idea, we will check this out ;)
RaketfuedRockets Ahh yup, totally understand it from a farmer's point of view. I guess if you are talking to the land owner you would want to get permission.
Yes, it would be interesting to see what the differences are between different foams as well as foam densities. We had done some earlier experiments with foaming agent concentrations and found that beyond around 3% there was little to gain as the concentration increased.
If you used fire retardant foam and used a heat activated trigger (approx 130 C) you could put one of these every 10 or 20 meters through the scrub and have an automated bushfire suppressor. Edward de Bono eat your heart out.
@Spoif- we too were surprised at the difference. We are not sure how foam performs in other rocket configurations yet, but from further flights this weekend for this rocket we keep seeing the same repeatable results.
You guys should add a parachute to the front for more stable landings cause with the one on the back causes the rocket to turn and dive in unwanted directions
CartUniverse pro gamer We try to aim at landing the rocket sideways as often as possible to reduce the damage to the rocket on landing. Landing the rocket on its fins can break them off.
What I ment is 1 chut at the front ant 1 behind to stablize the landing instead of flopping around in mid air
So that will always land on its side
CartUniverse pro gamer Ahh sorry I see what you mean. Yup, that should work.
AirCommandRockets I don't know the altitudes because I unfortunally don't have a altimeter. But It looked like the launchtube and foam combination worked best.
Maybe you can try that as well next time? 9mm nozzle and launchtube and 22mm nozzle and launchtube too? Would be nice to see how much a launchtube helps!
Olivier
Hello Air Command, very interesting results with the foam. Even when not using the Jet-Foaming Spacer you get great a great increase in Altitude. Over the summer (once School has finished and I have more time!) we will try adding foam and post a video to see if we have the same effect :) Are you going to add foam to the boosters of the Polaron G2 or just the main stage??
Hi Jamie, That would be great to see how foam behaves in other rocket configurations. You need to make foam in the rocket either by shaking it up before flight/during pressurisation, or during flight like with Jet foaming. Simply adding the solution to the water won't do much. You have to get a significant amount of foam leaving the nozzle.
Currently I am thinking that we will only add the foam to the main stage. We really don't have a way to make foam before launch in the boosters.
That's a significant increase using foam. Incredible.
Why does the hight increases if you increas the nossle area? Of course the rocket gets rid of the energy much faster. And that causes a higher Speed - > higher altitued. But here the air resistent is much higher. With a smaler nossle the Energie is provided over a longer time and the end Speed not so high. But the top Speed is reached at a higher altitued. And the lover Speed means not so much air resistance.
But still the rockets with a bigger nozzles fly higher. Why is that?
That's a good question, the amount of stored energy is the same in both cases, and you are correct in terms of how drag affects the rocket due to the different speeds. I am not completely sure why they are slightly different, but it may come down to the efficiency of the nozzle. A narrower nozzle will be less efficient than a wider nozzle.
@@AirCommandRockets Yes the funny thing is that i tried to write an altitude calc. for water rockets. That would help me to understand the relationsships between pressure, nozzle size and the amount of water you would need at spezific pressure with specific nozzles. I already built these for normal rockets without Differential equation
.It is like a step by step calculation.(with respect to the change of mass, air resestance and thurst). But for water rocket i couldnt manage that.
And i strugglet exact at the point you faced above.
For the specific change of velocity (from the water rocket) in a periode of time you need a specific amount of Energy. This energy comes from the kenetic energy of the water (Offcourse all that energy in that timestep). The kenetic energy (from the water) is calculatet with the mass and the velocity.
And thats the point were i stuck because the velocity is calculated from the accaleration (That is easy) over a specific amount of time (distance of acceleration). But what is this distance ???
And would it change change if you would use a straigt pipe instat of a bottle
I think the main question is: From where to where gets the water accelarated. (And does it change if you use a straight pipe or sth. else)
I think that is a really interrasting point to improve efficecy by a lot.
Im sorry for all the grammer mistakes because i´m just from a german high school.
Thats all just high school formulares i can´t read the fancy formulares form the internet
Double the distance of accaleration = four times more energy for the rocket
@@simonolschewski70 The best analysis of water rocket flight have seen to date is here: www.et.byu.edu/~wheeler/benchtop/pix/thrust_eqns.pdf
What would happen if you added your extension tube to the rocket with the 22mm nozzle? Would having the second stage give you more height or is it better to have one stage
Very nice onboard on that 22mm flight, so stable and so fast! Do you know why the rockets go way higher with foam? I think i'm gonna use it on my next flights as well. I am very happy that you guys tested this keep up the good work, as always ;)
Hi Basrockets. We're not exactly sure yet, we're trying to determine what the underlying cause is. I suspect it may be that the foam is exiting at a significantly higher velocity than water. Water is heavy but it also comes out slowly and air comes out quickly but is also light. Foam probably sits somewhere in the middle of those - higher density than air, but higher speed than water. We did another test this weekend where we had the bubble bath dissolved in the water, but there was very little foam in the rocket at the time of launch. The rocket flew to the same height as a water only launch. When we mixed up the foam in the rocket so there was a lot of foam in the rocket before launch, then it flew higher again.
If you get a chance to fly some comparison flights between water and foam, I'd love to hear about your results. We are not using the jet foaming spacer for these tests.
AirCommandRockets on my channel I've made a slow motion video from the launches with foam and without, even with a small launch tube.
I think the foam takes up more space just when it exits the nozzle, so the rocket can push it self of harder. it probably helps as well that it acts as if there is more water in the rocket but without taking up more space.
Do you know how to simulate a flight with foam?
AirCommandRockets Thanks for the big explanation on that rocket i see that you use a tornado tube. Do you think the foam will work the same way without a tornado tube? The rocket that i make is one big pressure chamber and no tornado tube of robinson couping, so i have to test if foam effects the results on my rockets as well.
Basrockets That's a good question. I think it will still work without the tornado tube as long as there are lots of bubbles above the water. It will be interesting to see the results.
Oli4vn That's a cool video. :) Do you have any performance data on how the rocket flew in the different configurations?
We currently don't have a way to simulate foam flights. I haven't seen any simulators yet that take it into account. I think in order to simulate it you would need to take into consideration the foam density, which may be a little more difficult to estimate.
I think this is caused by the foam expanding like the exhaust gases in a conventional combustion rocket engine. Adding a bell type nozzel might improve performance even more.
en.m.wikipedia.org/wiki/Rocket_engine_nozzle
Could it have something to do with aerodynamic pressure? I dont know the speeds involved, but it seems quite fast, enough to make air resistance a factor. Foam seems to last longer than just water, maybe the water one is flying too fast and hence encountering more resistance, hence wasting more energy?
+ComandanteJ I think that is a part of it. Foam produces about 2/3 the average thrust of water alone, but it gives you about twice the "burn" time. The upshot is that the rocket's peak velocity is lower and with drag being proportional to the square of the velocity, the rocket experiences less drag.
AirCommandRockets It's hardly rocket science. Oh wait... LOL
BTW, absolutely love your channel, i wish some day i'll have the time to get into it, and go from Kerbal Space Program and Orbiter to real rocketry, hehe.
Wery interesting. Why do foam increase high of flight? I had observed similar effect with concentrated solution of potassium carbonate. It`s density in 1,5 times more, than density of pure water.
I've watched several of your experiments using foam as propellant. I see the results but I don't fully understand why foam increases altitude performance. Have I missed an explanatory video?
Good question. We also don't know exactly the reason why foam is better. I suspect it has higher nozzle exit velocity. The rocket also doesn't travel as fast so it reduces the peak induced drag. (drag being proportional to the square of the velocity) Although the average thrust is lower than with water alone, it does double the amount of time that thrust is produced.
with all these tests is there an planned project/end result? a record of some sort in the works or just for fun?
Hi Michael it's mostly just for fun. The plan is to use the foam in some of the bigger rocket sustainers. We really enjoy watching the long slow burns, and the foam helps deliver that. :)
AirCommandRockets Could you explain why there's so much difference?
We believe that it's due to the exit velocity. Although the mass being ejected is less dense than water, it has a significantly higher velocity, and hence more thrust.
I am curious if it is just mass of the water that increases the distances. Would salt water also show an improvement? How about muddy water?
This is a good question. The liquid density does play a part in how much thrust is produced. The problem is when you make the liquid denser, although you get greater thrust, you also have a greater mass to lift with that thrust. The heavier mass is the result of the heavier liquid still in the rocket. A liquid of lower density than water will actually perform better than water. The other way to increase thrust is to increase the exit velocity of the mass you are ejecting, and that is what we believe is happening here with the foam.
Here is another comparison we did recently that compares the same rocket at the same pressure with the same liquid mixture (same density) except one has been shaken up to form foam and the other one is just the solution. You can see that the foam rocket goes significantly higher.
Day145 Water Rocket Highlights
Some further reading: www.aircommandrockets.com/water.htm
Great comparison! =)
I didn´t thought that the difference is so big.
The problem with foam in Germany is that it´s kind of illegal, because it destroys the ground of the fields.
Greetings from germany
Hi Raketfued, we too were surprised at the difference with the foam. Interesting that the foam is illegal in Germany, I wonder if you guys have different stuff? The foam we use is biodegradable.
AirCommandRockets
There is no law in Germany which says: Water rockets with foam are illegal, but it could be that some farmers take proceedings against the foam-launches, if we use it. Biodegradable foam is a good idea, we will check this out ;)
RaketfuedRockets Ahh yup, totally understand it from a farmer's point of view. I guess if you are talking to the land owner you would want to get permission.
AirCommandRockets
I would be happy if you send me a link of the foam that you use.
Thank you =)
I guess You also could see differnces between different foams.
Yes, it would be interesting to see what the differences are between different foams as well as foam densities. We had done some earlier experiments with foaming agent concentrations and found that beyond around 3% there was little to gain as the concentration increased.
If you used fire retardant foam and used a heat activated trigger (approx 130 C) you could put one of these every 10 or 20 meters through the scrub and have an automated bushfire suppressor. Edward de Bono eat your heart out.