Stormcaster build ?

[thrustnut]

Hi all,I'm planing on flying e-f motors in this one. Don't laugh, i glassed the body tube and will glass fin to fin.

My questions are,will the cheesie cardboard centering rings hold up? I will use epoxy on the whole build.

And the instuctions don't mension any rounding of the fins.Should i keep them squared off? I'm thinking that would be better for the landing

Ron

 

[Stefan_Jones]

You probably didn't need to fiberglass the body tube. That is a lot of extra work and extra weight. As it stands, you will have a very sturdy model!

The fins certainly could use some reinforcing. The fins on my Stormcaster seemed way too thin even for D motors. I personally would laminate them with paper. However, if you don't mind the work then fiberglass will make them nice and sturdy.

I would reinforce the centering rings. I have plenty of spare 5060 rings, so I would just double them up. However, you could make your own by tracing them on cardstock or balsa.

My Stormcaster came with a LOUSY motor mount tube. Very mushy, thin fiber. I would if I had a chance replace it with a sturdier tube, or reinforce the rear portion of the motor mount tube with fiberglass or paper.

I would round / streamline the fins. If you are fiberglassing them, that will make the leading and trailing edges plenty sturdy. You can wrap an extra strip of fiberglass along the trailing edge to reinforce it further.

Have fun!

 

[powderburner]

Those CRs are probably just fine as they are, but if you want to add strength you should add longitudinal webs between the motor mount tube and the inside of the body tube. These webs can be cardboard, or balsa (orient the grain inboard-outboard), but plywood would be waaay overkill. Anyway, these webs are to shear the thrust loads from the MMT to the BT, leaving the CRs to simply act as gas seals. Actually, since one of the CRs is notched so the motor hook can move, the other CR is the only gas seal. Making the CRs out of heck-for-stout material is about the least efficient way to do it.

If all the above is clear as mud, PM me and I'll step you through it.

 

[thrustnut]

I glassed it with 3/4 oz. cloth. It doesn't seem that heavy.I'm hooked on glassing very simple.I guess i'll round the edges.It just seemed how the tip would come to a point it would get dinged.I have 3 rockets glassed but haven't flow yet, dew to not being able to paint.Come spring time i'll be busy painting.

I found some extra rings i'll add them.

When i glassed the bt, i peeled the first layer of paper off.I thought crap the tubes were pretty flimsy.After i was done they were rock solid.

The mmt does seem mushy.I was thinking of epoxying some paper around it.Higher up the mmt so ejection charge doesn't burn through.mmt looks to be 8" long.

Thanks
Ron

 

[outasight13]

F21's (the max motor im assuming youre going to use) dont have *that* much power, at least not enough to warrant full glassing IMO.
I think you'd be better off just laminating the fins with paper to save some weight.
Dont get me wrong, What you did is cool and good for practice, but its overkill for a Stormcaster.

 

[cjl]

Well, there's always the F39...

That having been said, I've seen a stormcaster with no mods other than ca-soaked fins take an F39 no problem. It is completely unneccessary to completely glass it. That having been said, you will have about the strongest stormcaster that exists. Have you put in the MMT yet? If not, may I suggest 29mm It should be strong enough, and that would REALLY get it moving.

 

[thrustnut]

Powder i forgot all about that,great idea
i might just go with 3 cr's.

At first i only wanted to glass the aft section.With the fins sweeping so far back i wanted extra strenth.Then i figured glass it all.I wish i would weighed bt before and after.The glassed bt doesn't seem that much heavier.My 50 coats of primmer is what adds wieght.Yeah yeah i'm an overbuider i know.

No cjl i didn't,well i'm starting the mmt now.I thought about 29mm but think it's too much.I'll set up the Supercaster for e-9's to f-39's.I love the e-30's too.

I know one thing, come spring time the paints going to be flying.

Thanks for the replies everyone
Ron

 

[jraice]

I would hand bevel the fins, if you glassed before rounding or beveling the edge will be bare balsa after the sanding, I would use thin resin (whatever you used for the fiberglassing) to reinforce them. I had 3/8" thick plywood fins with airfoils around the edges and the chute was tangled so the fins hit hard, no damage, the thin finishing epoxy soaked right into the grain and made the fins very strong... also did this to a basswood custom cone from sandman and it made it very smooth and water proofed it (dont want to paint a beauty like that!)... I would say it sounds like you will be fine...

 

[Garnaralf]

I dunno about re-enforcing the fins at all. I don't think its nessesary.

The last flight I had of mine, with a shorted and spillholed chute, it landed one fin point down, stuck in the ground, and bounced back and forth for about 15 seconds. Just like taking a fishing pole by the tip, bending it, and then letting go.

The fins did not break.

And I used just good old yellow glue on it.

~Bob

 

[robfire820]

I am currently building 1 to handle a G55 that I have, I cut new fins out of 1/8" aircraft ply as well as made new centering rings, but I have all the great tools, as my father has a wood shop in his garage and my father-in-law has a metal machince shop in his.
I decided though to use the laser cut CR's from sunward, check them out they are great.

 

[jraice]

I am making one for a younger sibling for G power, probably G40, no G80's in this thing... and some F's as well, are the stock rings (sanded to fit a 29mm motor tube) strong enough? The rings are so small a fillet would completly cover them... also is 2 enough? I plan on leaving the tube as is... glassing the fins and the external fin/tube joint with 3oz glass and possibly a MPR recovery system (1/4" TN with a nylon chute).

 

[RoyGreen]

Originally posted by thrustnut
Hi all,I'm planing on flying e-f motors in this one. Don't laugh, i glassed the body tube and will glass fin to fin.

My questions are,will the cheesie cardboard centering rings hold up? I will use epoxy on the whole build.

And the instuctions don't mension any rounding of the fins.Should i keep them squared off? I'm thinking that would be better for the landing

Ron

Please, please, please.... DON'T OVERBUILD. You are just making an inefficent projectile that will be more dangerous when some weaker part (like the shock cord) fails.

1. Stiffening centering rings. Using three triangular gussets, with one side against the CR and the other against the outer tube, will be enough. Besides, I think the rocket's got through the wall to the mount fins, so if they are attached correctly, you've got plenty of reinforcement without gussets.

2. Fins. Yea, you could glass em, but don't use any heavier than 1/2 or 3/4 oz. glass. But really, just a layer of printer paper on each side is all you need for that rocket. Use an extremely thin application of wood glue, or tack it on with CA then use ultra thin CA and slowly soak in a little at a time until the whole fin is done.

Do that before attaching the fins so the tabs themselves will be stronger.

With the fins reinforced (oh, and yea, definitely round the edges), that rocket should take up to a G, maybe more.