My Experience while building World's Largest Hydro rocket

World's largest Hydro-Rocket

My experience throughout the journey..

Our aim was to break the previous World record of 73 feet vertical launch with not less than a rocket with dimensions of 0.45m in diameter and 4.5m height.

How we made World’s largest Hydro-rocket

Sir with due respect I am writing this note which will highlight the practical challenges we have faced while making World’s Largest Hydro-Rocket.

It all starts from scrap.

After Aishwarya Dhara, Pon Maa Kishan did registration for World record attempt, they chose Shiv Kumar for the project. Then later I asked them weather I could join.

They willingly accept me and asked me to build a model to physically simulate every possible aspect of the rocket (which we had done till the last moment of the launch). Fortunately, I already had one (2 half litter bottles joined).

We have done its flight test just for fun and it really flew to roughly an altitude of 25-30 meters.

This rocket answers our question:

Ø Can we build?

Ø Do we have required materials?

Then we did some research for required materials. Majorly we were searching for bottles with our required specification (2 litters minimum with a smooth geometry and nozzle cone), adhesive which could hold 80-85 psi of pressure and some other small tools.

Still, the test we have done were not satisfactory and so we were in argent need for the material. But there was a delay. We were already lacking behind as per launch date (4-10-2019) so we collect bottles from scrap and adhesive from nearby market. It was enough to do the required test.

Our next objective was to test the joint (single) along with to experience the launch pad.

We cut 3 bottles and joined (using ‘fevitite’) them one after another and let it set for 5 hours (although fevitite doesn’t need that much time). When tested, it got leakage within 30 psi that was heart breaking. But it helps us to realize that it is not going to be so easy. We found that the position where we had cut the bottles have uneven expansion rate under high pressure because their geometry was different and so the joints had to overcome normal (surface) stress along with shear stress. Result: We have to cut the bottle at the same location and join them in order to have uniform expansion.

We made two models to demonstrate the same. But this time we reduce the number of bottles from 3 to 2. One got failed but the other succeeded. For the first time we crossed 60 psi then we didn’t pressurize further due to safety reason.

Till then we were only dealing with joints in between two bottles. Then just for fun we did some launch and it was satisfactory (55-60 m) and give us more hope.

Still we have long way to go.

Next, we aimed to join one more stage where we could test not only bottle joints but also the joints in between two such module.

We used different adhesive now -Araldite. Because: The setting time of the previous adhesive (fevitite) was too fast to work with hence we were in need of such an adhesive which could give required strength as well as enough time to work with. We keep setting time as 6 hours.

To join the module, we used 32mm diameter PVC pipe and threads (generally used for plumbing). The PVC pipe inner diameter was just enough to fit the mouth of the bottle externally and then we glued them with araldite. After 6 hours of setting time we tested (without water, static test) and fortunately it withstands 60 psi without any leakage then we didn’t pressurize further due to safety reason. But when we took the same for launch site it starts leaking just after 25 psi from that very joint. But later we found that it was due to mishandling. So, by far we had tested all kind of joints using which we were going to connect all bottles up to 4.0 meters.

We had only 1 week left for the launch but yet we didn’t have material to start to build the main rocket. Till we get the material, we then start working for the launch pad (release mechanism).

We had many proposed ideas for release mechanism, we discussed many models including those on internet. But most of them got rejected either because we didn’t have required material or they were not reliable for the present model. Later we finally agreed on locking mechanism. It was easy to build and more reliable as it operates manually. Its 3-D modelling help us to look into its manufacturing problems which we solve parts by parts and then we had our final 3-D scale (1:1) model of our launch pad.

We had 5 more days for the launch.

By then our materials also arrived- 1000, 2 litter plastic bottles, adhesive, cutting tools, PVC pipes etc. and materials for the launch pad were collected from the workshop (not that of University).

We asked for volunteer and about 14 volunteers arrived who worked throughout the project and it is because of their working force that helped us to do everything within our time limit.

Some of us engaged in making launch pad while other were given work to cut and join bottles.

Now joining bottles has their own problem:

1) 1) It was very irritating because we were working with araldite with our bare hands. Once it got harden in hand it was too difficult to remove.

2) 2) The work has to be done with many concerns, like- in order to fit one bottle into another we were needed to enlarge the diameter of one bottle by just not more than 1mm. and the same has to be done to all 133 (required) pairs. Because we knew that there will be some defective item so 150 is what we have targeted. So, lots of work has to be done.

3) 3)
While gluing them there were frequently air bubbles coming in between, now they have to observe them very carefully because once they get set and still they will reduce the shearing strength of that joint and so even if after hardening we saw them than we had no other option than to reject that bottle and because we were already running out of time, we can’t afford that. So, the process was further slow.

1) 4)After putting araldite when they were left to get harden, because the araldite was just a viscous fluid s it was flowing out of the region. So, they were periodically turned upside down.

It took entirely one day and night for nearly 12 people to cut, expand, file, glue and fixed them. So, by next day we have nearly 170 set of bottles.

On other side we were also working on launch pad. Here the challenges we different. Initially, we were not given the required tool (by the workshop department). Even when material (iron bars) were available, we were asked to bring our own. We were than given conventional (hand hacksaw, used electrode etc.) and asked to grand permission to use modern cutting tools. We had all permission from HOD (Aerospace) but I don’t know what makes them uneasy to let us do our work. After 5-6 hours of – “please sir, OK sir, why sir” by the end of the day we could only weld the frame. In between we had to also face one more challenge and that was unavailability of the required dimensioned material. If you could closely observe the frame than you will observe two slots in which two clamp were supposed to slide. They were of defined dimensions. During design we assumed that those slots will be cut out from a single iron bar but we had no tools to do that and also our material were of little extra dimensions. So, on the spot we made few changes in our design and welded the frame.
It was really a good experience to do real engineering work.

It took us two day to measure, cut, positioned and weld all the parts.

All was going well, now we have to make pressurization system which is the heart of this project. The design we had was totally based on our previous test.

For pressurization too we had many ideas but most of them were not feasible. Another important thing was that we were not familiar with the problems relating to pressurizing water in a chamber with multiple nozzle. From our long discussion we came into conclusion that we will use rubber cork individually for each mouth as a water shield and drilling holes at its center than pass pipes to pump water as well as air.

We bought rubber cork (20mm diameter and 26mm height) but later we found that the required pipes which were supposed to go through rubber cork were not available and further we couldn’t drill our “conceptual” hole in the rubber cork. So, we had to give up this idea and then think some other way. We then agree to go as per our conventional way. And based on that we design our pressurization system as:

(Important thing to mention here is: the way we were solving our problems. What we were doing was to create a fixed path and then to solve the problems that comes in that path. This is good approach but only when we are fully aware of every possible happening which in our case was not. We were inexperienced in this domain. Although we made exactly how we had design but because we were inexperienced, we couldn’t fully analysis every possible problems we were about to face.)

Our pressurization system has only one inlet which were used for both water and air. We did this because we undermine the importance of valves. We had never heard about back flow and because we didn’t had a full scale test, we have seen the problem regarding water backflow only in the test which we have done after the failure. Yes, hydrostatic law holds preciously but we also had problems due to misunderstanding of – ‘water maintain its level irrespective of container’s shape’. Also, we never had experience of plumbing so it was another major problem.

As per our design a plastic pipe was to be fitted in place of cork. We use the plastic pipe because when we were testing single stage we had the same and at that time it was working very well (40 psi) but we were totally unaware of the fact that since it was an elastic pipe so under high pressure its expansion will be too large to neglect and the mouth of the bottle ~ inelastic.

Under high pressure the expansion of the pipe is so large that it totally and rigidly fits in mouth and hence will not release the bottle. Due to lack of time as well as knowledge of plumbing the joints of the base and other pipes (of the pressurization system) were not tested taken as granted. We were totally aware of the possible source of failure but because we were working at night and since the next day was the launch day. We had no choice.

By early morning somehow, we manage to assemble rocket, launch pad, pressurization system etc. working 24 hours without rest.

After reaching to the launch site by 7 am we took some rest and started to assemble at the launch pad. Then it’s the time when things start getting seriously wrong. We couldn’t efficiently work because we hadn’t sleep last night. And then the pipes were not getting inside the mouth. The main problem is- We didn’t know why? Since for single stage we did it easily then why not now. We initially thought that the pipes were too long as well as uneven (by few cm) so some of them were getting stuck in the mouth. We cut the pipe by 12 cm. No improvement!

Our problem was:

Those (blue) pipes, which were supposed to make the nozzle water tight during air pressurization, were not going inside the mouth of the bottles.

We were supposed to launch at 10 am but we have to postpone to 2 pm. However, the guest was busy and because he had to leave so we assembled anyhow and presented him – special thanks to Manik Sir (lab assistant).

We couldn’t launch even by 2 pm and again faculties postponed it to 5:30 pm.

We lost our hope by 11 am only but still we worked- we pull out the long pipes and forcefully inserted the blue pipes, with kicks and hammers, inside the mouth of the bottles. Then by 6:30 we start filling water and pressurizing the rocket. We were surprised to see for a while it worked well but as pressure increases many faults comes in picture. It is here where I have seen more faults then functioning in my entire life.

Faults:

Bottle leakage more than 6 out of 19
Leakage at the base (at T and pipe joints)
Leakage at the blue pipe
Back flow of water
Inefficient pressurization
Uneven water level
Lack of water pump and low volume air compressor.
Launch pad not level with the ground
Wrong orientation of the rocket in the launch pad (which is the major carelessness due to which rocket couldn’t liftoff)
Positioning error of the supporting rods

Etc…

At the end the rocket couldn’t lift off the ground but instead due to its own weight it crushed the pressurization system and, in this way, we had no choice but to accept our failure.

After the failure.

That failure was heart breaking. It was so heart breaking that even in those eyes where emotion is a myth you could see some viscous Newtonian fluid, salty in taste falling out of two near elliptical shape organ only sensitive to photon, drop by drop and under the action of gravity in a laminar way it flow and fall radially towards C.G of the Earth i.e. tears.

The result was as we have concluded early that morning. But by nature(human) we were sad because we have tried all the way we could. I could have taken that as a positive vibe but it was I (the leader) who was more broken then rest of the members.

Most of them left for home. I and the teammates along with Sir Manik (lab assistant), Sir Ponmaakishan and two more faculties were there to help us to collect the items. We didn’t have enough energy to collect all the items and bring back to the hanger (about a Km). So, the important items were collected and the rest were left for the next day.

What next?!!

I thought it was over, we have no more chance but still listening at Sir Ponmaakishan’s words I guessed that he will encourage us to do it again(as he too have to prove to somebody that he was not wrong by dreaming that project and choosing us; not among the best, to execute it) which I was not willing to. So, while returning to the hanger I told other team members (especially juniors) to continue the project (as per coordinator’s guideline) without me. However, I will provide any suggestion if asked.

By the time we reach the hanger, most of the team members had left for their room and only few of us were there. Basit, Shiv and Ankit were waiting for me.

Yes, those few days were the best days to celebrate our friendship.

As expected, Sir Ponmakishan tried to encourage us with his words. He told us (I forgot the exact sentence) that failure is very important otherwise we can never learn and if we stop there, we will become a subject to laugh so try one more time, they will apply for reattempt. But I was determined not to continue the project and those words hardly changed my decision because I never care who laugh at me (I already have many). I told the same to Sir. He constantly tried to motivate me. Few members wanted to do (with/without me). But because Sir was chief, he will not allow but only under my or Shiv’s leadership as Basit was not there when we started the project. However, Shiv (although he was willing to) sided me and said that he too will quite the project if I didn’t work followed by Basit and Ankit. I tried to convince them that I am not important and every one of them are experienced enough to lead. Sir gave one night to think and then he left, my friends too asked me to think for that night and answer them in the morning and also added that their answer will be- “Me too”.

That night I compensate my last 7 days of restless hours. Next morning was a normal day for me. We received message from Sir informing that they have accepted their reattempt application. I called Basit, he first asked me what I have decided then after hearing my answer he replied with- “May soo raha hu, mayrayko soonay day”. I went to see the exhibition for the first time but I was late. I forgot to mention that the whole project was a part of a week-long space exhibition as organized by the Aerospace department of Chandigarh University. Then when I came back, I found few of my team mates including my friends too waiting for me. They told me that if the team will do the project then it’s only under my leadership or else it’s just the end for all. They were not willing to do without me not because I knew more (many possessed more knowledge than me) but rather because (as few said) they may loss the ‘followed path’ and also my energy motivates them to work whole night. And because they were not willing to accept then I too told them- “Ok, leave the project” and then left for the room.

An hour later I came down to go for the stationary shop to buy a cold drinks but I found them still there talking to each other and waiting for me. All of them. They looked at me and again started to give me a motivational lecture (I forgot). This time they really convinced me. I simply wake up and without a word left for the room (they were unaware of my decision). I changed my dress and then came down and told them (I still remember that word as that was the time when I have decided to get success anyhow): “Chalo, bahut kaam baki hay”.

By hearing this they were more energetic then me.

We were having five more day to rebuild the rocket and I wasted the first half day. By evening we went to the hanger and discussed the plan.

First, we must be sure that we have learned a lesson which we really did. Then we must go through our mistakes, re-evaluate our design and discuss to improve and then implement them physically. That’s lot to do. But now it was a bit easier because the most advantage point for us was our ‘experience’ of what could go wrong.

We have enough bottles to build one more entire rocket but it was not necessary as most of the stages were OK. We only needed few- 7. Because we were enough but running out of time so I divide all into three teams.

Shiv and Milind with most of the members will look after the bottles.

Rocket was the most critical part of the entire system. We can’t improve the design but yes, they definitely have to look after and improve the process. They decided to go slow to improve the result. Most of the faults were in joints due to air bubbles in between and uneven breadth of the araldite. They have to check them and remove during the process and also to avoid flow of the Araldite the mixture ratio should be proper. Although we didn’t alter the ratio (50/50) but what we did was to keep it for a while so that it naturally gets hard a little bit and so easy to use. Our decision was not bad. It really helped us to improve our quality of the joints. Most of the team mates were engaged in this work.

Ankit, me, Basit and two juniors: we took the charge of leftover things.

We mainly indulged to reevaluate the entire design and do all shorts of possible but reliable changes. It includes most of the things like launch pad, pressurization system etc. Launch pad was mostly under Basit and Ankit’s vision and pressurization system was what I got in my list. But we three constantly comments on each other works.

For launch pad, we didn’t change anything in design but only its measurement. Previously, those four rode in which the entire rocket was placed got crashed at the end due to its own weight and later we found that it was the miss alignment of one rode due to which the base plate of the rocket gets tightly fixed and so the rocket couldn’t free itself but get crashed. So, that four rods need to be positioned exactly at the same defined position where the hole of the base plate comes in and also should be vertical so that all loads(weight) get distributed equally as we wanted.

All the above system were ok. Initially they got failed due to our carelessness and error in measurements. The main cause of failure was the pressurization system. Till then we couldn’t figure it out what really went wrong there. Initially we though that it was mostly because of its weak strength to handle shear load at various joints which results in leakage. So, we didn’t make any change in design but only improve our strength.

To improve strength, we bought metal joints (all T and L) and pipes as well and two valves for separate water and air inlets. They have inbuilt threads so it becomes easy for us to join them and luckily, we have got the connecting pipe of required length to make the rectangular network. To make it water shield, we also have plumbing tape. On the other side, Basit and Ankit were busy measuring, positioning and welding the rods. I really didn’t see how Shiv and Milind’s team were doing. The metal pipes have solved strength problem but what about water leakage and why we were facing problem to insert the pipes inside the bottles?

We then decided to test one small version of our rocket. We cut the defected stages and made all (19) nozzle height about 1.5m small prototype. We assembled our pressurization system with those crashed pieces and then start to physically simulate what really happened.

It was this time we found why we couldn’t insert the pipes into the bottles. Because we didn’t have enough force (manual power) to insert them. This sometime happens when we were testing our single nozzle rocket. But we merely took it into consideration. So, for multi-nozzle the ‘error’ grow exponentially and became a big problem. We thought to replace those long pipes with just the base pipes (blue one) only and then we will pre-insert into the bottle and into the pressurization system. For water leakage we tied the blue pipes with hose clamp. It really makes our work easy. It definitely improved but no success.

We then concluded that the pipes (those to go into the nozzle) diameter we too tight and so when we make our new version (with metal pipes) we won’t face the same because they were exact and with one layer of taping it will become water shield too. But the launch date was near, we have two more day to launch. By that night, around 12:00 am we assembled the new pressurization system. Initially, we had rectangular configuration but this time we made in a zig-zag configuration because we were facing problems to join various metal pipes at the T and L-joints. We assembled and by 1:00am we were ready for static test. This time we succeeded. Wait, hold on! We succeeded only to insert those pipes into all 19 nozzles with a little hammering. But it was ok for us.

Next, at that very night all were very excited to see how water gets fill and air pressurization. So, despite being tired we were ready to simulate how long it might take water to fill the required height (two vertical stages About 1 m).

That late night it was difficult to find that amount of water (152 litters) and also water pump. But luckily, we had a tape nearby. It also had enough pressure to fill the water. Then we started to fill the bottles. There were two valves, one for air and the other for water. As soon as we stared to fill, we face some leakage problems. But we fixed them and continue. This is the time when we show uneven raise in water level in all columns of bottles. Initially, we thought it won’t be much to consider because the water level was not much different. But as time goes on, the difference in water level was getting higher and higher. Now why this happens?

Because the path is zig-zag, so the air/water has only one way to travel. As we start to supply water, the air that is trapped in those pipes travel towards the bottle and so initially the pressure inside the last bottle was a bit higher than the rest bottles. As a result water gets fill lately. That is why there is difference in water level. Similar phenomenon was also observed in our first attempt. But the reason was different. If you see than the water level in this two bottle are very high. And this is because of leakage. When the water gets fill, the air was supposed to get compressed but due to leakage in this bottle they get escaped so pressure was ambient. Now because all the bottles are interlink, water from the other pressurized bottle starts rushing into low pressure bottles. Hence, there is very high difference in water level.

Now just think how you feel.

‘You stood after failure, you figured it out as much defects/problems you had and solve them step by step. After doing all possible modification with no time left for extra, result is same.’

It was already 2:30 am and now we only have next day to solve that freaking problem. We had no choice then to pack-up and go to sleep if we want our next day to be productive.

Next day, shiv team were busy testing leakage and they found only one. That’s a good work. Out of 9, 8 vertical stages were Ok. But we needed only 6. So, we have 2 extra. Then we assembled and discussed about last night problem. Different members have different solution but none of them were feasible. Either they were what we had rejected early or practically can’t implement at that time. Some were not in discussion as they believe now nothing could happen and blame that we have stuck to same idea rather than changing it. Yes, I accept but what could I do. Even HOD was with us pointing out what we have already observed. I then remember one. Initially when we were discussing about pressurization system. Sir had an idea of filling all stages individually but we rejected because it was too risky to proceed. If any accident happens and the rocket get launched out of our planned time then it could dangerously harm the one at the top. Also for as high as 5-meter rocket, manually filling was not an easy task. Everyone was busy in debate. I thought let me try. I call Basit and then we two make the required setting for a ‘Dice test’.

First, with a single nozzle bottle (one bottle) the entire mechanism was setup. It worked!

So, did in all previous test. Nothing new! Next, we thought to increase the number of nozzle to 3. We made the required setting for 3 nozzle configurations. Hurry! It worked again. I don’t know about other but I was so relaxed that I couldn’t think any more problems. That’s a success.

Now, everybody was sure that the rocket will get launched.

What modification were to be done for new configuration?

Not much, launch pad was same and so all but only the modifications were at the mouth of the bottles. We were to made 19 valve for each nozzle which were to be fitted at the top of the bottles and 19 corks (which we already had) to be fitted at the bottom of the nozzle to get the stage water tight. It might sound easy but No! Now we have to do most of the work, till the rocket get launched, manually. Any wrong method, failure is sure. By night we did all what were left, like making nose cone (credit goes to Ajay, Milind and Anjali), fines (credit goes to Ankit) etc. and also did one more test with all 19 nozzles. Success!!

Finger-crossed.

Next, morning we all get assemble at 6:00am and then took all the required tools and materials at the launch site. Now, everything went as per plan. Some small problems arose but we handle. Winter was near so we enjoyed the heat of the sun but soon got irritated. Slowly and steadily, team member starts assembling the rocket. Because nose cone was not ready yet. Few were given that task. Other were busy levelling, adjusting, fitting and fixing the rocket in the launch pad.

We had fun. By, 4:30 pm we were ready to fill water. We bought a crane to get into that height. I went up and ground command was under Basit and Ankit’s while compressor control was under Shiv and Sir Manik. It took almost 50 minutes to fill the water in all 19 columns of bottles (~152 litters of water) then some measurements were taken and video for official purpose were recorded where our official guest confirmed what we have targeted.

Diameter comes out to be 52 cm and height 5.2meter in size we broke the record. Now, next was how far it will reach. We then began to compress the columns. Some minute things were to be consider here like the way we compress the bottles. They shouldn’t be done randomly otherwise due to nonuniform pressure distribution about axis, the rocket might get tilt and could possibly fail the launch.

I slowly compressed the air one by one. First, all 19 were pressurized up to 30 psi then our next aim was to pressurized them to 70 psi (which we planned). 13 were successfully pressurized with one leaking but we fixed it at that very moment. As we started to pressurize the 14^th one, one of the bottles get blew-off. All were surprised and shocked. One stage starts leaking out from the base as its cork got lose since the rocket gets tilt to its side because of the force from the blast. But, Basit and Ankit handled the situation in the ground and then Shiv decided to get launched without delay. Now our goal was not to break the record but rather to get launched out of the launch pad. I stop pressurizing the system. Nose cone was handed to me where electronics were fitted. I placed it at the top and then I was pulled out of the zone.

Here starts the countdown.

Ankit and Bhanu were given to pull the clamp and Basit starts countdown: 3-2-1 and there it gets lift off the ground, our 10 days of relentless work, day and night, vertically towards the night sky glittering with stars and moon. Finally, it gets launched. I was still sitting at the top of the crane shocked and void of thought looking at the team mates joyful moments. I was happy because we did it together. There were other 100’s of audience too and they too were happy because it was not only our success story but success for whole Aerospace department of Chandigarh University.

Then we collect the data. As per that we achieve 104 feet (previous record was 73 feet). So, by this way our team of 17 young and unexperienced students 3 faculties with Sir Manik made a new world record of World’s Largest Hydro-Rocket achieving World Record height of 104 feet.