Looking beyond Level 2

[kcobbva]

As my L2 Certification launch approaches, I find myself forward thinking about an eventual L3 Certification. I think my desire to achieve the L1/L2 as well as everyone’s awesome support on the board have greatly attributed to my success so far. Now I believe there are things I must learn to properly prepare and make informed decisions moving forward. To date I’ve learned to use Paper tubes; fiber glass tubes; how to prepare them. RocketPoxy over BS epoxy; glued on motor retainers; Ebays with pull pins and rotary switches and things of this nature. While at the time these appeared difficult; all appear rather normal now. To that end - I’ve never done actual glassing of paper tubes or composite fins. I have no idea how screw switches work; unsure of how to mount/use shear plates; no radio/gps devices; no experience in making hatch covers, nor why foam in fin cans, etc. Also no experience in the use of chute bags. I’ve seen numerous conversations around many of these subjects on the board, and I know all these things would greatly benefit (are necessary) growth and knowledge toward the L3. So after I complete my L2 event; lord willing this weekend; what kind of suggestions would you all recommend as a next project moving me closer to that knowledge level that would help in pursuit of a successful L3 design (Be it kit or scratch)?

I’m not sure I can incorporate all of these in a single project; but is there a kit that might require a lot of these type skills that I might focus on next? Or is it time to scratch build and work through the design now? I have rocksim; so the later isn’t an issue other that actually getting parts and understanding why certain parts should be used to withstand the forces required. I tried to download aerofinsim and sent an email requesting access; but to no avail. I thought that would be a good tool to use. I don’t have a shop or garage, which always makes a build a challenge, but it won’t stop me necessarily. I welcome all comments and opinions, and thanks in advance.

 

[webtech]

Well there is no rush in to level three, that is for sure.
Whatever you want to do next is up to you. I spent four years working up to my level three project.

When you first start on your level three project you will have to work with a L3CC member on your build construction package.
And they can answer all of those build questions for you.

I worked on perfecting my dual deployment skills and my tracking skills before jumping into my big rocket.
My plan was to be able to dual deploy in my sleep.. one less thing to stress out on while getting ready to fly the big one.

I think my next project is going to be a minimum diameter, just haven't figure out if its going to be 54mm or 75mm.
best of luck to ya.
~Russ

 

[Bat-mite]

Fiberglassing tubes requires tools and space. You need a mandrel and something to spin it on. Lots of videos out there.

GPS can be as easy as a 900 MHz unit (Eggtimer or BRB900) shoved in a nose cone. I drill a hatch in my NC, stick the transmitter in a long piece of foam rubber pipe insulation, tape over the hole and let 'er rip. If you want to go the radio route, you need a ham license and call letters.

A screw switch is just a rotary switch that goes inside the AV bay, accessed thru a hole, and turned with a long, flat-blade screwdriver. I like the exterior-mounted 110/220 switched, myself. Never used a screw switch.

A shear plate is just a small, thin piece of brass or aluminum that you epoxy to the tube and drill a hole through. Cuts the shear pin w/out ripping the tube. Only necessary for thin cardboard/paper tubes.

Foamed fin cans provide extra support for the fins, to prevent them from breaking free from the MMT if the epoxy joint weakens. Again, not necessary; but I have done it with both of my MAC Performance kits. You just mix it up and pour it in. Cut the excess off the top when it bubbles over.

There is a how-to article in this month's Sport Rocketry that shows how to make hatch covers. Check it out.

My advice on L3 is: don't do what I did. I bought a high-flying kit that took me to 13k'. I didn't see either deployment event. I didn't see the landing. (You can read my Level 3 thread.) I wish now that I had gone low and slow like everyone suggests. A big, heavy rocket on a baby M to 6k'.

If you do that, you may not need GPS. If you use a traditional AV bay, you won't need a hatch cover. If it's fiberglass, you won't need shear plates.

If you want to invest in tube rolling, watch some videos, then get yourself a mandrel, some FG cloth, and some laminating epoxy. Roll your own tubes to be as thick and heavy as you want. Simulate it first, of course.

As for D-bags, I might get there some day. But to date my biggest chute has been a 60-incher which I burrito wrapped in an 18x18 Nomex protector. From what I gather, a D-bag is similar to the backpack that a skydiver wears. Others can chime in on that.

You should meet Tom Cohen. He scratch builds all his rockets out of glassed Sonotube and plywood. They weigh about 150#, and he launches them on CTI M3700 motors to about 1100'. Separate chutes for the NC and airframe. He uses a hatch-accessible AV bay, down near the fin can so that the switches can be activated without a ladder. He is usually at all MDRA launches, and I have learned a lot from him.

 

[BDB]

Hi Kevin,

I'm a few months behind you, but I plan to be L2 by this summer (Hope I didn't just jinx that.), so I've been thinking about my plans too. I think there's a lot to do between L2 and L3. Here is what I've come up with so far:

Use GPS tracking (I already have an Eggfinder and an Eggtimer TRS)
Mach + mile flight (I already purchased a 54 mm MD Mongoose kit that is next on the build pile)
2 mile flight (I need a higher waiver!)
HP cluster (I'm probably going to mod and glass a Minnie Mag kit)
Upscale some of my favorite kits from childhood
Complete scratch build using only parts from Home Depot/Lowes
HPR Multistage

I think that list should keep me busy for a while.

Brenton

 

[Bat-mite]

Honestly, the reason that I didn't do a lot of that stuff was that I wanted to get my Level 3 credential, and then have the door open to whatever I want to do.

 

[Exactimator]

I like your idea of learning all the different techniques and going for your L3 on something new and different than your L2. Your list is interesting, but (as I’m sure you know) made up of different techniques that aren’t needed for an L3. It sounds like you’re close to having the skills you need, with the exception of tracking.

If you want a short gateway project to L3 with the skills you already have, you can build a 4” fiberglass rocket with a 75mm hole. A RW Broken Arrow 4XP or Madcow 4” DX3-XL for examples. Install redundant altimeters and a GPS, and launch it on K’s and L’s with a 75-54mm adapter. A few practices and you’re essentially doing an L3 launch. Put in a baby M and you’re good for your L3. Just make sure you communicate with your TAP while building it.

In the meantime, there’s so much to do within the L2 cert. Lots of rocket/motor combinations to achieve different things. You can go over mach and two miles on a lot less than an M. You can implement all your list items and field test them (either with kits or scratchbuilt). You could play around with those for years before you L3, trying something new every launch.

I’ve been contemplating getting my L3 a lot. I figured out all I really need is to build a booster section with a 75mm MMT, put the top half of my X-Celerator on it and I’ve got my L-3 rocket. After a lot of thought I finally decided to wait indefinitely. I already have a heavy rocket I don’t launch often because of the motor cost. For one launch on a K or even large J, I can launch my H and I rockets multiple times. If I can find a low cost booster section I’d do it. Otherwise, I’ll wait until I hit the lottery.

 

[markkoelsch]

Do not be in a rush. There is a lot to learn, and it is a BIG jump in power from say a small J to an M. Take your time, make sure you not can make things work, but understand why they work. It is not a race.

 

[kcobbva]

All

Thanks for the responses so far. I appreciate your responses as I think about this. While I am very "eager" to accomplish this; my L1 advisor gave me the same advice that Mark just did. After some reflection, very sound advice. I know I wanting to do this; but getting to a few launches around the area sporting larger rockets, and talking to the builders about how and why was good advice I received. I have a bunch of zooch kits to keep me active; and dont get me wrong, ill be thinking about this quite a lot; but I think "Take it slow" is very wise advice. I give that same advice to young techs coming into my career field. Its time to look in the mirror and just learn for a while. Again, thanks for the feedback.

 

[CzTeacherMan]

Quick note about screw switches... I use them exclusively and love them. Missileworks screw switches are sturdy and easy to use. I mount them on the sled. So I've got a sled that is readily movable asking all my DD rockets. All I have to do is add new charges and setup is a snap. No JST connectors to worry about, etc.
There's a million ways to skin a cat, and this is just the method that works best for me...
I'm on track to get my L3 this spring. Much faster than I thought I would get it. Basically, I've just done what I always do: ask questions relentlessly. Measure twice, ask thrice, epoxy once.

 

[mccordmw]

My desire for L3 is to make my own EX motors. As a phd in biochemistry/molecular biology/cell biology who works in an organic chemistry industry, I'm hip deep in that type of stuff and love it. I don't need to make them big, but making my own is attractive. I'm mostly lacking in building skill, so I love to tinker with tubes and gizmos.

I've still got other goals like mach+, min diam., altitude, alternative deployment. There's so much to experiment with that doesn't necessarily need L3.

Good luck with your journey!

 

[dixontj93060]

My desire for L3 is to make my own EX motors. As a phd in biochemistry/molecular biology/cell biology who works in an organic chemistry industry, I'm hip deep in that type of stuff and love it. I don't need to make them big, but making my own is attractive. I'm mostly lacking in building skill, so I love to tinker with tubes and gizmos.

I've still got other goals like mach+, min diam., altitude, alternative deployment. There's so much to experiment with that doesn't necessarily need L3.

Good luck with your journey!

You only need a L2 cert to participate in research, not an L3.

 

[mccordmw]

You only need a L2 cert to participate in research, not an L3.

Really? I must have misread the TRA info. Good to know. Thanks!

 

[Bat-mite]

L3 just means M, N and O impulse. That's it!

Like Exactimator wrote, if you are flying L motors in a 75 mm MMT, just add another grain and you're flying L3.

 

[kcobbva]

Quick note about screw switches... I use them exclusively and love them. Missileworks screw switches are sturdy and easy to use. I mount them on the sled. So I've got a sled that is readily movable asking all my DD rockets. All I have to do is add new charges and setup is a snap. No JST connectors to worry about, etc.
There's a million ways to skin a cat, and this is just the method that works best for me...
I'm on track to get my L3 this spring. Much faster than I thought I would get it. Basically, I've just done what I always do: ask questions relentlessly. Measure twice, ask thrice, epoxy once.

Ok, so then what is the difference between a 110/220 rotary switch mounted and a screw switch? Are they mounted in such a way that you can turn them on through the static port? Guess I'm going to have to see them and how they work to get this one.

 

[Bat-mite]

Screw switch mounts to the sled and is turned on via a screwdriver thru the static port.

 

[kcobbva]

Screw switch mounts to the sled and is turned on via a screwdriver thru the static port.

Any reason other than low profile from the rotary style switch? Get the same positive connect/disconnect?

 

[CzTeacherMan]

Ok, so then what is the difference between a 110/220 rotary switch mounted and a screw switch? Are they mounted in such a way that you can turn them on through the static port? Guess I'm going to have to see them and how they work to get this one.

I've attached the picture of the board for my L3...
The 110/220 switches are larger and often mounted into the wall of the av bay and connected with jst connectors. To me, it's an extra possible failure point (though many many many people use them with zero issue).
To turn on the screw switches, I just use a longish screwdriver through the vent holes of the av bay. Two switches about 1/4" apart can easily be turned on from a 3/16" vent hole.