L3 4" Frenzy

markkoelsch said:

I did my L3 on a Wildman Extreme, which other than not having split fins is pretty similar. Mine ready to launch sans motor is 16.4 pounds. I think the K400 is likely a bit light on thrust. Might I recommend the AT K805 Green for this rocket. Good kick off the pad, and should get you about 4000’.

The M1850 would likely get you a little over 15000’. I did my L3 on the M1297, and got about 12600’.

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I want to go a bit higher with this rocket. My L3CC has recommended that I go with the M1315 for this, so that is what I will do. I'm purchasing some used hardware from Performance Rocketry. It's the 75/6400 case with closures. It's been used 3 times so should be okay. FC has a few scratches but that shouldn't be an issue. I have ordered an 84 classic chute from Fruity chutes. Should be here in 2-3 weeks. I have some fillets done, but I have unfortunately run out of rocketpoxy so I have to halt progress for the moment.

mperegrinefalcon said:

One question:
For the fillets I want to thicken up the rocket poxy a little bit. I picked up a box of different fillers at the launch I went to last weekend. I have colloidal silica, milled fiberglass, and carbon fibers that I can use. I've not used fillers in a build before, so what would the difference be between using these materials?

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Milled glass or carbon fibers will make the fillets stronger, and the colloidal silica will help it stay in place once you put it somewhere. However, all of that will be an absolute bastard to sand smooth. If it was my project and I had that mix of fillers, I'd mix carbon and glass milled fibers into the epoxy until it gets to be hard to place without looking like a hairball (exact amount depends on the length of the fibers). Then pick up a fillet size chunk of the mix and see if it sags. If it sags, add colloidal silica until it doesn't.

After that, you'll probably have a rough surface. I'd file it smooth-ish with a coarse round file and then apply a thin layer of epoxy thickened with microballoons. That will make your sanding to smooth fillets far easier.

YMMV and others may have more suggestions.

boatgeek said:

Milled glass or carbon fibers will make the fillets stronger, and the colloidal silica will help it stay in place once you put it somewhere. However, all of that will be an absolute bastard to sand smooth. If it was my project and I had that mix of fillers, I'd mix carbon and glass milled fibers into the epoxy until it gets to be hard to place without looking like a hairball (exact amount depends on the length of the fibers). Then pick up a fillet size chunk of the mix and see if it sags. If it sags, add colloidal silica until it doesn't.

After that, you'll probably have a rough surface. I'd file it smooth-ish with a coarse round file and then apply a thin layer of epoxy thickened with microballoons. That will make your sanding to smooth fillets far easier.

YMMV and others may have more suggestions.

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It's actually fumed silica, not sure if that makes a difference. I have made one set of fillets where I mixed up a batch of Rocketpoxy and added 1 tsp of the fumed silica and half a teaspoon of the milled fibers. This stopped it from sagging like it usually does. Apparently in 95 degree weather Rocketpoxy completely cures in 1.5 hours. There was a slight misshap that I will post about when I post the pictures. I was actually sanding it about 1.5 hour after I had mixed it, and it was completely solid. They are some of the best fillets I have ever done.

Heyo,

Sorry I haven't updated this thread in a while. I have been working on fillets and sanding them and I've been really busy with work and starting my rocket company. I will have pictures of the fillets and my work on them soon.

In the mean time I have made up an openrocket mockup of how I want to paint it. Let me know what you think of it.

I will be using an Iwata RG-3L with a 1mm needle to spray it and some acrylic enamel paints and urethane clear coat from Sherwin Williams automotive finishes.

I read you added fillers to Rocketpoxy...this is a NO..NO!
As per the specs, all needed fillers are already added. Adding anything else only weakens the bond strength. You thicken it by mixing and waiting for it to go through 3 stages....
1st semi runny...bonding part
2nd thick....fillets
3rd claylike....filling divets... holes.... weight...shaping parts[missing tips, chipped NC's]

I am posting this in hopes anyone else reading this will not add to RP.


Seems to me if you are starting a rocket company, would it not serve your advertising tremendously, to L-3 on a kit of your own design? Finish this..fly it have fun, but certify with your own Falconry rocket.
Would get you some much needed free advertising if you do it right & cement that you know what you are doing. Design something capable & proven to handle L-3 successfully.

Just a thought & some free marketing advice.
[that is...if you are the guy with Falcon rockets, if not....disregard]

blackjack2564 said:

I read you added fillers to Rocketpoxy...this is a NO..NO!
As per the specs, all needed fillers are already added. Adding anything else only weakens the bond strength. You thicken it by mixing and waiting for it to go through 3 stages....
1st semi runny...bonding part
2nd thick....fillets
3rd claylike....filling divets... holes.... weight...shaping parts[missing tips, chipped NC's]

I am posting this in hopes anyone else reading this will not add to RP.


Seems to me if you are starting a rocket company, would it not serve your advertising tremendously, to L-3 on a kit of your own design? Finish this..fly it have fun, but certify with your own Falconry rocket.
Would get you some much needed free advertising if you do it right & cement that you know what you are doing. Design something capable & proven to handle L-3 successfully.

Just a thought & some free marketing advice.
[that is...if you are the guy with Falcon rockets, if not....disregard]

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Ya, I thought about that. I might actually not fly this for my L3 cert. The Excaliber design that I posted in my Falcon Rocketry thread would serve that purpose well. I just have to see what happens with money and all that. If I get enough funds I likely will make a 4" version of the Excaliber to L3 on. I just have to see what happens with money. The kits I am starting out with all don't have 3" motor mounts and the money is really all going to making kits to sell. I am going to a launch with a banner and hopefully I can take some pre-orders there. Money is my limiting factor.

On the topic of RP. I had seen that somewhere else, but unfortunately I had already done my structural fillets. I only added about a teaspoon of fumed silica and 1/2 teaspoon of milled glass fibers for every 60 grams of epoxy, so hopefully it hasn't weakened it much. I am just doing the 2nd layer of fillets with RP now. I am just adding some glass micro balloons to it so it is easier to sand and fumed silica to make sure it stays in place. I am doing 60 gram batches with 1 teaspoon fumed silica and 2 teaspoons of the micro balloons added to the mix. This is an extremely thin layer going on the fillets, so it is't structural at all. This is just to make it easier to sand and make the fillets have the correct shape.

Sorry I haven't been updating this thread, this project has stalled since the prototypes for my Falcon Rocketry kits have been arriving. I should be able to get back to it fairly shortly.
I just have some sanding I need to do and get a coat of primer on this rocket.

mperegrinefalcon said:

Sorry I haven't been updating this thread, this project has stalled since the prototypes for my Falcon Rocketry kits have been arriving. I should be able to get back to it fairly shortly.
I just have some sanding I need to do and get a coat of primer on this rocket.

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That is what happens when your hobby turns into a business. Falcon Rocketry comes 1st.

crossfire said:

That is what happens when your hobby turns into a business. Falcon Rocketry comes 1st.

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Yes it does. I just had to finish my first prototype and now I am working on a different prototype. I am just waiting for the epoxy and CF I ordered to get to me. In the mean time I can do a bit of work on this. I have a build thread on the other one as well. It is the 54mm extreme minimum diameter build. I am trying to get to 30K on an L935 with an on board camera on my minimum diameter kit design.

On another note, I will not be going for my L3 cert any time soon, and not with this build. I will have fun flying it on large K and L motors though. I am thinking I will fly it on a L2200 (As if it's not green enough)