Tuesday, September 26, 2006

Mr. Bartel's Comments and Concerns

This is an email Mr. Bartel sent to me a week ago. Everyone please read this and pay close attention especially if it has anything remotly to do with your job. If you have any questions or comments on this, do comment please.

-Serena

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Here are a few things that I will mention to you that I have concerns about:

1) I don't think that the Estes engines are going to get the team where it needs to be - to much variability in the propellent mass, nozzle dimensions (not sure if this is a factor), and especially the delay timing. Also we are going to be pushing the ability of this engine to get us the extra 50 m.

2) The options are to go with an 'E' sized engine from Aerotech (which might have the same issues) or to use an 'E' reload-able engine.

3) Would the team consider a electronically controlled ejection timer? Currently the engine has a delay built in and then burns a little more propellant to pop the parachute. I think the built in delay has too much variation. We could build an ejection system based on commonly available parts. I stumbled across a web-site that could be adapted to provide a safe way to generate ejection gasses fired electronically -
I would have to work with the person responsible for this, but ultimately, they would make design choices and built the system.

4) I think the team ought to consider having the booster separate from the payload section for recovery. The rules say that this is acceptable, and the time is based on the part of the rocket that carries the egg. Our last flight separated on accident and the booster section tumbled down undamaged while the payload took too long to get down due to less weight. If we design it this way, I think that there will be less variability in the dynamics of the descent so we should be able to be more consistent. The payload and parachute can be exactly the same for each flight - no variation in weight.

5) We ought to try to find a balance for weighing the rocket and components - more precise. Along with this we need to consider some kind of field table that can be leveled and possibly shield against wind.

6) I would like the team to buy a composite launch rod (much like an untapered fishing pole). This will be straighter and resist permanent bends - unlike the current rod. Here is a link.
We need to check the rules to see what the length requirement of the actual rod will be (we might be able to get away with the 6' length, but we could go for the 12' length and trim to size if needed). When we go to Va, we could take the rod with us ensuring a consistent drag due to the launch rod.


1 comment:

Serena said...

correct