First Scratch Build

[No Laughing Man]

Hey, I am new to this forum and have found it as a great resource. I am pretty new to rocketry also. I have built a few kits before and have launched a couple times. I started this scratch build that is designed to be a egg/cargo lifter with an AT RMS 29mm 40-120 motor casing. I hope to eventualy fly it with a G motor.

I have only done work so far on the payload section. It is a BT-70 body tube and has two layers of 1.5 oz. fiberglass applied. I am considering adding two more layers. The same will be done to the sustainer over the next few days.

I have also cut out the fins. I put the original design into RockSim and used it to find a fin design that would provide sufficient stability. I plan to also cover them with two layers of 1.5 oz. fiberglass. I will downsize this photo tomorrow.

I have a few questions though. Would it be worth it to add another two layers of fiberglass, especially if I plan to launch this on a G motor? I am also planning on using an ejection baffle, anything I need to know about installation or placement? And as far as glassing the fins, I have seen that some use wood filler and hardener on them. Should I still do that even though I am glassing them?
Thanks for any help.
Kaijah

 

[cjl]

Glassing the BT is really unnecessary, but especially as the grain direction on those fins is about the worst it could be for strength, I would glass them several times tip to tip (also, if you can, recut them with the grain parallel to the leading edge of the fin).

 

[No Laughing Man]

Thanks cjl! Better to fix any problems with the fins now then later. I tried to cut the fin as you said, but found it about a half inch to thin and ran out of wood at the same time. I will post a picture later. Which now raises another question, will balsa (I have a ton of the stuff) be sufficient for this project or should I get another type, such as basswood (what those fins are made of) or ply?
Thanks,
Kaijah

 

[TWRackers]

I'm just curious... is your handle a reference to Ghost In The Shell: Stand-Alone Complex?

 

[cjl]

Glassed balsa would be fine, ply would work fine, basswood would be fine (I would probably put a layer of glass on them regardless though just for extra strength).

 

[No Laughing Man]

Yes, the name is inspired by the series. The attempt was to find a name that would fit as a Xbox Live ID (The laughing man was one character too long). As a result NLM came to be, though it doesn't have much to do with its origin anymore. Here is the recut fin in balsa. I found the balsa I used to be a bit too flexible and am going to order some ply when I order the last parts I need for the rocket.
https://i41.photobucket.com/albums/e286/No_Laughing_Man/rkt_RTS_pre_fin_2_small.jpg

 

[zog43editor]

The grain looks much better on that one.

 

[No Laughing Man]

One month without an update, but I finally got most of the parts remaining that I wanted. I am using 3/32 5-ply plywood for the fins and plan on adding a layer of 1.5 oz fiberglass today or tomorrow. I also am installing a Aeropack motor retainer, and have a Rousetech clone of the AT RMS 29/40-120 (I really like that gold finish).

Preassembled Fuselage and Parts

The center tube is a baffle, though I am not sure an exact placement and how it will effect the rocket. And one of the new cut and tapered fins.

New Preglass Fins

I hope to get the engine mount and fins together this week and then finish up the nose cone. Any suggestions or corrections are very appreciated. Also, I plan on the upper part of the rocket being a cargo compartment. I was going to make the nosecone detachable, any suggestions on how to secure it during flight? I was thinking of simply using 3 or 4 small screws. I will post so more pictures later.