Fin design and material needed

[Wei Chun]

Thanks for the help appreciating it. Waiting for part 2....

[bugwubber]

Next step is just to apply filler such as spot putty or epoxy etc. You want to use something that will gap fill and not foam.

Then its just a.matter of sanding smooth and painting.

[bugwubber]

Sanding at 220 complete. Think I'll finish with a finer grit before painting.

[Wei Chun]

Thanks and it really help me

[bugwubber]

Thanks and it really help me

Great! Good luck on your contest!

Here's how it looks with paint.

[Wei Chun]

Last thing, can i know the measurement for a trapezium but 1 of the slated side is straight 's measurement and how much water in the bottle is the best to fly far?

[bugwubber]

That's where experimentation is going to give you the best answer.

My fins usually range from 1.5" to 2" but, whether they are better than 3" I can't say. If you have time, try a couple variations and see if any go higher.

I will say that you need to make sure they are as equal and as balanced as possible. This is where simple rectangles can be an advantage.

[Wei Chun]

How much water is needed and what is the best launching angle to fly horizontaly?I have no time to test it already as it was given last week abd I completed the rocket already......

[Wei Chun]

One last question, how much water is need in the 1.5L bottle and what is the best launching degree for maximum horizontal distance?

[bugwubber]

Water-1/4 to 1/3 of your volume depending on your air pressure. Lower pressure, less water. You are trying to get max horizontal dist? Its 45° for ballistic trajectory, but might try a few different angles if.you can .