Project week

[anoymous]

Hi
In this topic I will post some videos of our test flights and rockets
Before someone says something about it: yes, our fin holder is in metal, but it was the easyest solution for adjusting the wings and for easly switch between different bottles. First post is expected monday.

[bugwubber]

Looking forward to seeing your work.

[Blenderite]

*Gets the popcorn ready*

[anoymous]

Sorry. I didn't have much time.
Here is an update: we tried the radial deploy system, it did work on our small bottles, but we couldn't straighten the plastic for a bigger cover.
Then we came up with our own idea, but the first one didn't work at all (A cover held in place with two rubber bands on the bottom and held up by two rubber bands attached to a servo motor.
when the servo motor turns, the rubber bands should detach from the motor and the other two should pull it down. couldn't get our parachutes in the compartiment).
The second system onsisted of two doors held in place with a ring cut out of a bottle. the ring is pulled up by the servo motor and the two doors fall down (helped by rubber bands). It worked when I walked up and down the stairs with it, but it didn't work outside.Or it opened after launch or it didn't open at all.
Now we will launch without a parachute, just with a lot of a foam to make sure the altimeter isn't broken. After the first tests, it worked, and somehow this is helped by the weight balance of our rocket: it comes more or less down sideways. It won't go high, tough: only 20 metres (one bottle, plus minus 4 bar and 1/3 filled). I think it tumbles too much on his way up.

I was going to post a film here, but I can't find it on the tablet (actually I found it, but not in the uploadscreen of the forum)

[bugwubber]

For 2l bottle covers for radial deploy check the local $1 store for 2-1/2liter or 3 liter bottles.

I find it easier to post videos to youtube and then post a link here.

[anoymous]

I think they don't sell 3l bottles in Belgium. We tried to make a cover large enough from 2 1,5l bottles, but as we can't straighten it, we can't use it. Photos and videos will be posted next week, as I am on vacation and only have my 3ds to use for internet.
results of friday: we tested different pressures (3;3.5 and 4 bar- we couldn't get a higher pressure with our bicycle pump) and different bottles. A lot went wrong: only at the third set of mesurements for 3.5 bar we got the results. With the different bottles: only the first launch of the first bottle was recorded. In total, we got 10 recorded flights from a total of 20.

[Blenderite]

You could always try to create your own 3 litre bottles.

Amazon sells the preforms here:

All you would have to do is heat them up gently (water bath?) and then pressurize them inside a mold that would prevent them from expanding too much. I have wanted to try this but have not yet gotten around to it.

[U.S. Water Rockets]

I think they don't sell 3l bottles in Belgium. We tried to make a cover large enough from 2 1,5l bottles, but as we can't straighten it, we can't use it. Photos and videos will be posted next week, as I am on vacation and only have my 3ds to use for internet.
results of friday: we tested different pressures (3;3.5 and 4 bar- we couldn't get a higher pressure with our bicycle pump) and different bottles. A lot went wrong: only at the third set of mesurements for 3.5 bar we got the results. With the different bottles: only the first launch of the first bottle was recorded. In total, we got 10 recorded flights from a total of 20.

You don't need a bottle for a parachute cover. Any large plastic sheet will do. Some people have shown us how they made it from the plastic clear binders you would put a printed document in. Any kind of plastic will work.

[bugwubber]

You don't need a bottle for a parachute cover. Any large plastic sheet will do. Some people have shown us how they made it from the plastic clear binders you would put a printed document in. Any kind of plastic will work.

I'd go so far as to say flat sheet is preferrable to using bottle material for the cover. My only fail was because I stored the cover wrapped around the rocket so that became its preferred/memorized shape. It actually fought against the rubber band and refused to let the parachute out. So my advice, no matter what you use for material, store the cover flat or at least not wrapped.

[Blenderite]

I agree that it is not a good idea to use bottle plastic for a parachute shroud. If the release mechanism doesn't produce enough force to move that flap out of the way, either the parachute could get trapped inside the rocket completely or it could get caught on the door and either damage the rocket or not slow the rocket down enough.

[anoymous]

sorry, I couldn't answer last week because I was in Austria on vacation. In the mean time, my dad repaired the altimeter (some wires came loose and the servomotor was broken). He also found a cover for the radial deploy system. Today we tried to do some tests, but our time was limited and at the first launch our rubber band didn't release fast enough. Result: lawn dart. This destroyed our second servo motor and my dad needed to buy another one. after that the weather was too bad to launch.

[anoymous]

Last weekend we did again some tests, and this time it worked every time, except when we forgot to arm the altimeter. The crash was very devestating, and the cover that holds the micro-sd on the reader was totally broken. So we needed to buy another card reader and yet another servo (the fourth or fifth). One photo is from the broken reader, the others are from our launch platform and our rocket and the wing attachment

[anoymous]

I just discovered I can't post photos: they appear in the attachments but aren't visible in the post. How can I fix this?

[bugwubber]

Might be a browser issue. What are you using? There is also a "post inline" button above image filename once it uploads.

[anoymous]

thanks for the info! I was using my tablet with windows 8. maybe that was te problem.

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