Minie Magg: L1 cert build

So I finally decided on what to get for my cert rocket, and what motor hardware to use (Pro29 3 grain and 6 grain so I can fly the full line) and the kit arrived yesterday.

(Leviathan for scale)
I'm basically going to build it stock, no nose weight but with epoxy on the fin locks, and a 18 inch nomex. Can a mostly stock build handle an H410? I'm considering flying that motor after cert.

Yes, a stock MM build can handle any H motor you want to put in it. The "1 caliber stability margin" rules are a bit too conservative for short, stubby rockets. Keep the CG ahead of the fins, and you should be good.

I also did my L! with the Minie Magg - popular choice. The one suggestion for modification would be replace the elastic shock cord with nylon and anchor it to an eye bolt in the top centering ring. Use a nomex sleeve to protect the first few feet of the nylon.

Afterwards, a fun modification is to use that giant nose cone volume for an altimeter bay, chute cannon, etc.

Yeah... H410...


If you want a really run ride... Snag an H399. Almost a full I, and it has a whole lot more impulse than the H410.

Sounds great, I added a base drag cone and stability is ok. The shock cord I got was 18 feet of tubular nylon, and I got a 18 inch nomex for the chute. The one thing that confuses me is that the fins do not provide any reinforcement to the motor mount like conventional TTW fins- is sliding the motor mount in with no glue and then adding epoxy fillets enough to handle 500-1000 newtons?

Blackbrandt, who makes the H399 and what casing does it use? I also though a H999 could be fun :dark:

The reason I am using 29mm is mostly so I can fly the same casings/ reloads in my G-Force, MDRM, and other 29mm rockets.

The fin lock mounting system is very strong. It can easily handle what motors you can put in the thing. The fin will break outside the tube on a rough landing before it lets go inside due to motor. Another plus is they are self aligning. The H410 won't even cause the fins know it's there. The surface mounted fins on my Onyx held up to the 410 just fine. While the H399-H999 sound like fun, they require electronics.

As far as the motor mount strength goes, the bottom centering ring buts up against the tabs on the fins. The aft centering ring acts like a thrust plate. The retainer pushes on the centering ring, the ring pushes the fin tabs and the body tube. It is all very robust. People mod these things with 54mm mounts all the time and they hold up just fine.

I really enjoyed building mine and the fin mounting let me do something I never planned on. I built mine with a Slimline retainer because I had one lying around. I wanted to fly more Loki's in it and Slimlines aren't exactly snap ring case friendly. Since the fins weren't glued to the motor tube, it was to remove the motor tube and retainer and glue a new one in with an Aeropack.

I just looked at your picture closer, it appears the fins are thicker than the older Maggs. Mine I believe are 3/16. Yours appear to be 1/4. Nice!

It's definitely 1/4, same as the CRs and madcow parts. I forgot that the fins reinforce the rear CR. Good to know I don't need to worry about strength on the fins and CRs. I think the instructions say to basically slide the MMT with the front CR glued and then just add a fillet of epoxy, is this safe?

grouch said:

The fin lock mounting system is very strong. It can easily handle what motors you can put in the thing. The fin will break outside the tube on a rough landing before it lets go inside due to motor. Another plus is they are self aligning. The H410 won't even cause the fins know it's there. The surface mounted fins on my Onyx held up to the 410 just fine. While the H399-H999 sound like fun, they require electronics.

Click to expand...

Check your facts. The H399 comes with a 12 second delay:

SCrocketfan said:

It's definitely 1/4, same as the CRs and madcow parts. I forgot that the fins reinforce the rear CR. Good to know I don't need to worry about strength on the fins and CRs. I think the instructions say to basically slide the MMT with the front CR glued and then just add a fillet of epoxy, is this safe?

Click to expand...

I glued my aft centering ring to the motor tube first because I wanted to be sure I got the retainer flush against the CR. I put a ring of tape around the front part of the motor tube so that the CR would not slide down, I made sure there was about a 1/4" of the motor tube above the CR. Then I put a band of epoxy inside the body tube where the forward and rear CR would go making sure there was a thin bit on the fin tabs too. Once I had the rear bit installed, I slide the forward CR onto the assembly until it met the tape stop I made. I let that set up then put a small fillet on the forward CR. It is hell for stout, in fact it's one of the stronger mounts I have built.

Thanks for the clarification BB. I fly Loki and CTI, haven't messed around with Aerotech yet. I plan to change that next summer though. I was thinking the 399 was one of the plugged Warp loads.

I'm using a madcow retainer so spacing shouldn't be a problem, so I think I'll glue the front CR. Thanks for the help though, I'll try adding a fillet on the BT where the centering rings will go. I'm going to use 30 minute epoxy so there is time to adjust the motor mount and get the aft CR aligned.

That will be a cool rocket fo you --- suitable for high-power, but also flyable at Moffett on G motors. That thing looks robust. And that fin shape is perfect for landing on concrete. Thanks for posting a comparison pic with the Leviathan --- that gives a great sense of the size, and I had been under the impression that model was smaller.

Wow! Love the size comparison next to leviathan. I have a leviathan and have been eying a mini magg, that pic just sold me!

Our club just went with Mini-Mags as club projects, and a few of us flew them in a Mass launch at Airfest. Mine is the red-white-&-blue.
https://piedmontrocketry.shutterfly.com/pictures/41
I used 1 1/2" PVC Conduit, a male and female threaded pieces to make a motor retainer, and for my Loki motors, replace the female PVC retainer, with a metal compression ring, from a sink trap.
I also updated my LOC 29/38 motor adapter, with a metal thrust washer. I got the washer from Ace hardware, with the proper inside diameter to fit around a 29mm Motor mount, and then ground down the outside, to fit inside my retainer ring. I then mounted an Estes motor retainer on it. The adapter can use either retaining ring, to hold it in the 38mm mount.

I have less then $10 in the retainers, and adapter

Very Patriotic !

Stars and Stripes forever !

H250G is good in this size too if you wanted to start an AT set of hardware - almost all there 29mm HPR loads are non HAZ .

Kenny

mikeyd said:

Our club just went with Mini-Mags as club projects, and a few of us flew them in a Mass launch at Airfest. Mine is the red-white-&-blue.
https://piedmontrocketry.shutterfly.com/pictures/41
I used 1 1/2" PVC Conduit, a male and female threaded pieces to make a motor retainer, and for my Loki motors, replace the female PVC retainer, with a metal compression ring, from a sink trap.
I also updated my LOC 29/38 motor adapter, with a metal thrust washer. I got the washer from Ace hardware, with the proper inside diameter to fit around a 29mm Motor mount, and then ground down the outside, to fit inside my retainer ring. I then mounted an Estes motor retainer on it. The adapter can use either retaining ring, to hold it in the 38mm mount.

I have less then $10 in the retainers, and adapter

Click to expand...

Hey, nice paint job! I also flew my Minie Magg for my Level 1, on an H123. Only made it to 900 ft (I tend to overbuild), but it was a successful flight!

As I recall we all used I motors for this, mine was an RMS-EZ I357t, good straight flight, no added nose weight, no stability issues. On the paint I just painted the rocket blue and white, then used 1 1/2" red vinyl tape, and went to Hobby Lobby, and got 2 sheets of 8 1/2" by 11" vinyl stick on sheet, and a Scrap-booking "star" punch, and punched the stars from the vinyl sheets, then just placed them where I wanted them.

SCrocketfan said:

So I finally decided on what to get for my cert rocket, and what motor hardware to use (Pro29 3 grain and 6 grain so I can fly the full line) and the kit arrived yesterday.
View attachment 184317
(Leviathan for scale)
I'm basically going to build it stock, no nose weight but with epoxy on the fin locks, and a 18 inch nomex. Can a mostly stock build handle an H410? I'm considering flying that motor after cert.

Click to expand...

This should make a fine level 1 rocket, basically that is how I built mine, flown on an I with a short ejection, so deployed 'chute still on way up, stripped half the parachute cords, but still came in, using it as a streamer, and landed in the grass, with no problems, ready to fly again.

Got the leading edges of the fins rounded a bit and sanded the surface of all the fins with a mouse sander today. Also got some gorilla glue epoxy for the build. Hope to fly it for cert (and maybe a big H or I using a CTI 29mm 6 grain case) at October Skies.

Also, just realized the H399 will fit the 6 grain casing I'm getting. Might be fun to fly, I'm not planning on getting the 6GXL case since 1800+ feet is enough for me, especially with motor deploy at apogee.

Finished sanding, and will be epoxying the fins in a few minutes.

The Magg is an excellent choice for L1. It also lends itself easily to many different modifications after you have achieved your L1.

This is my modified scratch built Magg and the modified business end.

Very Cool! 7 38mm mounts?

Are those fins 1/4 inch thick?



TA

No, they're .187 G-10.
This is a scratch Magg, the only Loc parts on it are the coupler & stiffy for the E-Bay and the nose cone shell
Those are 29 MMT's not 38's

SCrocketfan said:

So I finally decided on what to get for my cert rocket, and what motor hardware to use (Pro29 3 grain and 6 grain so I can fly the full line) and the kit arrived yesterday.
View attachment 184317
(Leviathan for scale)
I'm basically going to build it stock, no nose weight but with epoxy on the fin locks, and a 18 inch nomex. Can a mostly stock build handle an H410? I'm considering flying that motor after cert.

Click to expand...

I mean these fins?


TA

1/4 inch plywood. This is one of the newer kits that has the "fin lock" bar and the fin connections are really strong. The fins are all glued, pics soon...

I got a bit more building done today. Glued the fins in place yesterday, and got the motor mount glued in a few minutes ago. It will still need CR fillets, and the fins need Titebond fillets, but the majority of the build is done. I sealed and sanded the fins yesterday and sanded the NC so after the rest of the fillets it's finally ready for paint!

It's pretty amazing how well the kit goes together isn't it? I am liking the 1/4" fins. Kinda wished mine had them too.

Very cool project!

grouch said:

It's pretty amazing how well the kit goes together isn't it? I am liking the 1/4" fins. Kinda wished mine had them too.

Click to expand...

It looks like it goes together really easy and is super strong. The field our club flies on for its low power launches has a limit of G motors or smaller, 1,000 foot ceiling, and you land on concrete. This looks like a perfect rocket for those conditions. I'm starting to want one...

Do it Thirsty! ;^)


Sent from my iPhone using Rocketry Forum

SCrocketfan said:

I got a bit more building done today. Glued the fins in place yesterday, and got the motor mount glued in a few minutes ago. It will still need CR fillets, and the fins need Titebond fillets, but the majority of the build is done. I sealed and sanded the fins yesterday and sanded the NC so after the rest of the fillets it's finally ready for paint!

Click to expand...

Nice, when did they start coming with 1/4 inch fins? I might have to buy another and go 54mm with it.


TA