christheman200

I have at least to the end of summer holidays plus one to two months to "finish" the project for school. In all likelihood the project will be due some time next year. As well, if it isn't finished by the school project due date, that doesn't bother me at all, since I can keep working on it during my spare time. Just keep bugging me on this thread to do more work so that I stay motivated! I will put together the design for a test rig right after writing this message. Perhaps on the first iteration of the craft there will be no egg. Yes, I agree with you on the learning aspect. My father is blown away by what I've been learning in the past few days. I can't imagine what I'll be like in two months. Even if I don't get near to completion on this project, it drives me forward to learn advanced topics. I have assembled all of my notes into my favourite binder, which has a drawing I drew of the space shuttle, pre-launch, on the cover. Any pieces of paper without binding holes have been put into sleeves. I should start a blog, shouldn't I?

The weighted probes are not likely to be implemented. The reason behind this whole project is to come up with a working automated landing system. The egg just incorporates it into a school project. For the sake of simplicity, it may be a good idea to ditch the egg and just create a lander. However, if possible, it would be really cool to land an egg safely with the craft. Perhaps an automated system should be created first, and then an upgraded version could carry the egg?

The analog altimeter has the potential to be perfectly accurate and work every time. It would save the weight of having onboard sensors to do the task as well. However, a system of accurate height measurement to control the descent is still needed. This makes the analog system fairly redundant, although redundancy is usually considered good in these systems. I know that this could be done in a much simpler manner, but I am trying to give myself a very hard challenge on purpose. If I can overcome this obstacle, I will have learned a lot more than if I had taken on a smaller task. In general, I would like the rocket to be as simple as possible yet be within my rules, and if the rules can't possibly stick, they can be adjusted.

I used 1.1 kg to account for the rocket with 100 grams of water left, and a dry mass of 1kg. The 47 Newtons of force calculation came from a rocket mass of 4.8kg, since I need a mass fraction of 3.8, meaning 1kg dry mass and 3.8kg of water. 4.8kg x 9.8m/s = 47 Newtons I like the idea of using a bladder tank, but I don't think using one is possible at 400psi. Carbon fiber seems to be the way to go. I know NASA does their tank pressure testing by measuring the heat and size of the tank, as well as other variables instead of swelling them up until they explode. I need to re-read over some of my tank design books. I didn't consider the drop in pressure as water leaves the tank. This will throw my calculations off a lot. Perhaps a compressed CO2 tank can be injected into the system to maintain a pressure of 400psi. Having the rocket slow down at just the right time is the idea. Fall testing the egg is my next priority, and will give me the ability to truly define the characteristics of the rocket's flight. The idea is to touch the egg to the ground, and then let go and fly away. In this case we don't have much margin for error if the rocket fails, however if the rocket performs to expectations the egg should survive intact. Creature, I'll give your excel integration a try. I have no experience in Excel, but it still seems like a lot less work than teaching myself the math behind it. Learning matrices, complex numbers, and Matlab this week have already put a good strain on my brain. I've realized your point on drop height. I just think that if I can find a building to drop it from it might seem a lot more awesome than dropping from a few feet. It also gives a longer time for the chute to open in-case their is a malfunction. The analog altimeter seems like a smart idea. As mentioned above the idea isn't to land, but touch the egg directly to the ground. Here's a record of my initiatives in the past few days: I made a sheet with equations that defined the characteristics of the rocket, which I now have to redo because of the change in pressure over time. I made a rough draft of a poster to send to academic institutions in my area. I will further this either today or in the coming days. I've gone through all of imaginary and complex numbers, matrices, and have started linear algebra on Khan Academy. I've made a list of egg mass vs. egg major and minor axes. By combining this with drop test data I hope to seek new incites into the mechanics of egg dropping.

Duxwing, it seems like autonomous landing is not necessary. Every gram saved is a larger tolerance for error. From a single internet source, I shall assume that the egg can withstand 3.75 pounds of force, or 16.7 Newtons. I will need to test for this myself. The first problem with your calculations is that you are not including the changing mass of the rocket over time. The second major problem is that the exhaust velocity of the water is around 25m/s. To provide a force of 10.78 Newtons with a weight of 1.1kg: 10.78 = m-dot * 25 m/s m-dot must equal 0.43kg per second To provide a force of 47 Newtons with a weight of 4.8kg: 47 = m-dot * 25 m/s m-dot must equal 1.88kg per second To solve this you need to do some integration. If ANYONE knows how to integrate this problem, please do so and provide some basic information on how it was derived. I'm still learning the prerequisites for calculus. Using simple geometry, the exit nozzle of a water rocket at 400psi with a weight of 4.8kg, providing a force of 47 Newtons must have a radius of 0.489cm.

A few days of hard thought has been put into how I should approach the DragonEgg project. I have decided to take a marketing-oriented approach to the development of the final product. This means that I will be advertising the concept where applicable in order to gain funding and/or partners. Lander development will continue as usual, however more focus will be placed on finding support. Appended is the first draft of a poster to be circulated among local universities. It is not quite what I would like it to be, and the wording must be redone, but it is just a first draft. What recommendations do you have that I can implement in the next iteration?

I'll likely use telemetry. I'm looking into the fiber composite bottles.

I'll greatly accept any help you can give me with the code once I get to that stage. I'll be using a composite pressure tank of some kind, and with enough research and testing this method should be safe. I had the idea to use a 50 meter tall board with painted black and white horizontal stripes, and an onboard camera to measure the number of stripes passing by per second. Filtering with gyroscopes to cancel out any rotational impact on the velocity would give you as much accuracy as you need. It seems ridiculous but it might be the best option. I've just purchased a copy of Matlab so that I can start learning it's environment and start modelling some of the aspects of the craft. My father also asked one of his colleagues from university if I could get a tour of our local university's engineering/aerospace divisions and if he could find me a mentor in the aerospace division. The rocket will be called DragonEgg, and if I create my own valves they will be named Python.

Using NASA's terminal velocity indicator, with a parachute 6 feet in diameter and the coefficient of drag set to 1.3, at a weight of 10.5 pounds, the terminal velocity is indicated to be 4.5 meters per second. That is quite a large parachute, but it certainly would take away a large portion of work for the rockets, and give a lot of extra time to react before landing. If the rocket were released from the parachute at an altitude of 10 meters, there would be a potential change in velocity of 14m/s plus the already existent 4.5m/s. That adds up to 18.5m/s, well within the delta-v budget of ~30m/s. The fall would take 1.429 seconds without any forces acting on the rocket.

I like your simple approach, Duxwing. I never thought of using a spark gap to sever the connection with the egg, however I have my doubts about the strength of the tape. I feel that the are too many variables for it to be possible to pull off a suicide burn landing, but it is simpler so I'll look into it.

That is ingenious! K2, I know a number of people who have worked with 400+psi systems before so I'm hoping that they can give me some help on that issue. If you didn't know, your average cheap 2 litre pop bottle, with a bit of splicing and reinforcement, can hold up to 200psi. There will initially be a parachute to slow and guide the descent, which would greatly reduce the impact speed. If dropping the rocket from the parachute at 10 meters up, there's only 14m/s potential acceleration there, and some of that is lost to drag. It would already be going pretty slow. I'll have just over 30m/s of delta-v to pull the maneuver off from there. Are there any options for relative altitude measurement that can sense from ~15 meters, even if they aren't commercial? I've heard of some quadcopters using a wireless link to a computer to be controlled, perhaps external sensors could sense the rocket's height and work from there? I'm still considering high delta-v options, but I don't have a university aerospace department on my side... yet. I'd rather make sure that an option like a water-rocket isn't possible before moving onto something a bit more complicated.

I generally agree with you, K^2, but I'm definitely going to stick with using rockets of some kind. I have arguments with a few of your points on hybrid rocket engines, but they aren't worth going into detail for right now. I did some rudimentary math and to land the egg with a bit of clearance room for small maneuvering errors, I will only need a craft with a mass fraction of 3.8 at 400psi (this is for a water rocket). At least in the theoretical physics part of the project, it's doable. I have a lot of time on my hands in between now and when the project will be due. And my teacher luckily will not take any marks off if I can't finish the project by then, having talked with him on the subject.

Yes, constructing a hybrid rocket to land an egg on the ground does seem rather overkill. Doing some math, I will only need a mass fraction of 3.8 for the rocket at 400psi. This is certainly achievable. I am pondering the design of my own, lightweight, high pressure, throttleable valves at the moment. Could anyone here give me some advice on the use of composite materials such as carbon fiber?

Building a hybrid rocket is still a large problem. Control logic is certainly a huge factor but first the rocket must be modelled. Are the pulsed operation hybric rockets pulsed on and off quickly to control thrust?

I haven't thought of using hybrid engines! I can see way too many complications with them, but if working would provide lots of power. As for valves, http://www.smcpneumatics.ca/en.aspx has a large supply of pneumatic valves which I believe are throttleable. For those suggesting I take a different approach to the project, I will not be doing so. This is going to be my first real venture into rocketry, and even a failed attempt would look great on my resume.

It was just a very rough guess. I suppose 6 seconds at 1G is much more reasonable.

I will be in contact with some higher level members of the Canadian Space Agency in the near future, and am hoping that someone there will be able to guide me. I am hoping to receive support for the project from a few major local aerospace companies that I have connections with. I feel that the maneuver could be pulled off with around 6 seconds of fuel at 2Gs. Is anyone here capable of calculating what size pressure tank would be needed to sustain a force of 2Gs for 6 seconds with a dry weight of 100 grams plus the weight of the tank? If no one goes for the challenge I will attempt to work on it when I wake up later today.

Actually, the problem isn't the thrust, but the delta-v. Average water rockets have 1000+ newtons of thrust at launch and pull an average of 160Gs. They only sustain thrust for around 30-60 milliseconds however. I remember earlier this year the water rocket competition held in our technology class! I overloaded my rocket with water, but it still flew rather high since it was reinforced and capable of high pressures. The parachute deployed, but it did not unravel. The nose cone looked like the lid of a garbage can. Fun times!

For one of my high school 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 fast-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"! Since we are on a rocket simulator forum, I'm assuming there are a number of you who have a solid background in engineering and design.

Had to go with Wally and Eve... I live Wall-E

I'm 14 here and I'm teaching myself rocket science from Travis Taylor's book "introduction to rocket science and engineering". I just bought my first telescope after a year of research, and I'm planning on making my own rockets soon. I can tell you that KSP inspired me to do all of this.

My entry: http://imgur.com/a/2co7i#0 Too many pictures to put on this page, so I'm keeping it all on imgur. I decided to take it all the way to Pol this time! In total, I believe this is worth 170 points, plus whatever it is for returning, since it says 5-100, which makes no sense 10 for accepting 5 for orbit 30 for leaving SOI 50 for getting beyond Dres 75 for landing on an outer moon (Pol) 5-100 for returning Thanks for taking a look!

Before the patch, about 300 plus, and since I have started with 0.20, about 10 parts. I have no clue why, I've checked all my processes, and I've lowered my settings to minimal, but it's terrible.

I've been getting 10 fps since I updated I used to get a consistent 50 before!

Aaaaaaaaaaaaaah!!!!!!!!!! I've been waiting for this! Absolutely astonishing! Great job.