First ever scratch build

[Tanarin]

So... what happens when you get a boring evening, a spare kit you have no need for, and leftover inserts from a Mega Mosquito? Well a good idea for a scratch build, that's what.

So throwing in the design into Openrocket, I got this:



I am a bit concerned about the stability on this one, but in theory it SHOULD all be OK. Simulations have this rocket hitting a possible 1600 ft on a C6-5, but I dunno if I would ever dare touch that on this rocket once complete. Only question I have before I continue is should I consider adding a small amount of nose weight to this, or should the stability be fine once I launch it?

 

[fyrwrxz]

Be aware once you push the button-your recovery system will shift under g-loads. Mite now be enuff mass to be concerned about, but the Cg/Cp is a little close.

 

[Willie]

I too think that Cg is a little too close. For that diameter, aim for 1 to 1.5. Just one man's opinion.


Willie

 

[hornet driver]

Be aware once you push the button-your recovery system will shift under g-loads. Mite now be enuff mass to be concerned about, but the Cg/Cp is a little close.

I'm on board with that evaluation. It's a bit short coupled so a little more bt length would be better (best choice) or a bit of weight in the tip. Since your using off the shelf parts the weight in the nose might be your only option. If I had to call it I'd say you would have a safe flight as it is but I THINK it might kick over a bit and then get stable as the speed goes up and the motor mass falls off.

 

[Tanarin]

OK, well what I actually did was added about 50mm to the thing and it brought it up to 1.83 cal. So guess that solves the problem of noseweight. Only thing I am really missing now is a 6 inch parachute. I tried testfitting a 12, and the fit will be a little tight given the length. Though I may also do dual 30 in. streamers, speed is a bit fast though at 40 fps according to openrocket. I was going to use marking tape as my streamer material.

 

[TopRamen]

Any updates?

 

[Tanarin]

Any updates?

Heh, I was about to actually post one when I saw this.

Anyway, managed to put it together. By the time I made the change to a longer tube though, I already had the original tube glued in. It can't fit a 12" too well, but I still feel a 6" will be just fine, if not streamers.





Again, KINDA worried about how the fall rate sims on Openrocket, but then again I dunno how accurate it is with streamers.

 

[cjp]

What did OR show the CP to CG with smaller fins?You might put a foil on the leading and trailing edge if you want more height.But a cool looking design.When I have large fins made from balsa,I paper them.That makes a very strong fin.