Water Powered Egg Lander

[christheman200]

After more research and simulation, I have found that I was grossly overestimating the weight of the rocket by approximately 2 times.
The mission should be achievable at 120 psi, which is within the range of commercial parts.

[The Mooseheads]

For one of my courses next year I will have to construct a lander capable of returning an egg safely to the ground.
I don't find this particularly interesting, so I'm going to be one upping the criteria and constructing an automated water rocket lander, sky-crane style, that will place an egg gently on the ground with no packaging to protect it. The criteria I have set out is as follows:
The egg must be placed on the ground intact.
The egg may not have any materials protecting it. Only a harness may be used to attach it to the sky-crane.
The egg must be initially positioned 50 meters above ground.
The egg must be returned via retro-water rockets, and a parachute may be used as long as it is not active upon touchdown.

The idea comes about from the Curiosity lander's unprotected nature upon touchdown. If NASA can land an unshielded 1 ton rover on Mars, why can't I land a simple egg on the ground?
For the automated descent I am thinking of using software from a quadrocopter to land softly, utilizing gyroscopic and altimeter sensors.
Their will be one or two pressure vessels, and 4 nozzles spaced out around the frame. Individual quick-response valves will control the thrust of each nozzle, in order to keep the pitch of the craft under control.
I will have access to a 3d printer with dual-extruders to print water soluble plastics, metal and wood CNC machines, and a machine shop once school starts back up. I can currently use SolidWorks, AutoCAD, and Inventor to model the craft, although I have access to just about every modelling software on the market.

I am looking for knowledgeable partners in this venture, especially in the areas of calculations and pressure tank materials. If you find this interesting please consider "joining the team"!
Is this possible from the rocket-systems point of view? Can the jets be fired long enough to make contact with the ground?

This sounds like a really ambitious project. Are you trying to make a replica of the NASA sky crane with high fidelity to the original concept, or will you take liberties with the idea? The first thing that comes to mind is the way the rover was dropped on the tether and cut loose after it touched down. You might have better luck if the tether did not need to be rolled out. If the egg was on a small platform with a landing sensor that was hanging below the crane and the crane just used thrust to gently land the platform and then it moved off to one side and landed itself, that might be simpler.

The weight of a crane motor and batteries for it are going to reduce flight time, and the flight time is going to be so limited that you may not have time to unroll a cable from the crane. For a reinforced 2l bottle you might get about 15-20 seconds of full thrust.

I hope you do this, because it sounds really fascinating.

[christheman200]

The idea is to take a few liberties with the sky crane design. However, I'm also interested in a SpaceX Grasshopper style lander that carries an egg as payload.

May I ask, is it actually possible to get 15-20 seconds of full thrust? I haven't found this to be the case in my calculations.

[Blenderite]

Can you put that in English?

[U.S. Water Rockets1]

The idea is to take a few liberties with the sky crane design. However, I'm also interested in a SpaceX Grasshopper style lander that carries an egg as payload.

May I ask, is it actually possible to get 15-20 seconds of full thrust? I haven't found this to be the case in my calculations.

Anti-Gravity research made a rocket that had a tiny nozzle and used compressed nitrogen at over 1000PSI. It was creating thrust for a very long time. They had a video of their launch on YouTube at one time, so you could easily time it with the video player time clock. It did use some kind of soap to make foam, which does prolong the thrust as the cost of reducing the thrust at any given moment. You might consider this as an option, but it might make the calculations harder, as foam is not well understood even now. It might be possible to use it and just use trial and error to tune the PID controls for stable flight.

It sounds like a really ambitious project. We're going to be interested in watching your progress. It looks very cool!

[christheman200]

They have a very interesting (extremely) high pressure design. For now I am building a large 120 psi water rocket, which I will test for performance.

[U.S. Water Rockets1]

They have a very interesting (extremely) high pressure design. For now I am building a large 120 psi water rocket, which I will test for performance.

That should be sufficient if you are just trying to halt the descent and make a soft touchdown. You probably don't need to hover or anything. It should be interesting to see your progress!

[christheman200]

Update:
I've tracked down the components that have eluded me for the past few months. I threw together a cardboard mock-up of a gimballing nozzle, which is working just fine. What 1/2" ID 100 psi tubing would you recommend that would be somewhat flexible under pressure?

[bugwubber]

Update:
I've tracked down the components that have eluded me for the past few months. I threw together a cardboard mock-up of a gimballing nozzle, which is working just fine. What 1/2" ID 100 psi tubing would you recommend that would be somewhat flexible under pressure?

Perhaps that braided nylon tubing they make for always pressurized connections to washers, sinks, toilets etc?

[beginingrocket]

really 400 what are you doing really I would only do 200