Minie Magg build

Started on building a Minie Magg today. Was surprised to see the fin attachment method - I'm not overly keen on this method and I'm concerned about its resistance to lateral force on landing. It's done with wedges through plywood (see pic) and they are not attached to motor tube. What have others done here?

Some options:

Fins - lots of epoxy and chopped strand Mat for strength on the inside of the tube. Maybe some microfibres in the epoxy too if I have some left.

Thinking about fibreglassing the tube by taking the glassine off and putting a couple of wraps on so that the external fillets get a better bond. Only trouble with that is that it will add thickness to the tube and so the nosecone will no longer be completely flush on the top edge.

Other mod I will make to the kit is to have two lifting eye bolts in the upper bulkhead to help resist zippering forces.

I'm keen to not add too much weight as motors are expensive here in the UK but I'd like the option to be able to fly it on J motors on the odd occasion.

I built mine stock. Once glued up the fin attachment is really strong and I have grown to actually prefer it in some cases. I have somewhere in the neighborhood of 15-18 flights on mine mostly with large I's and have never had an issue with the fins at all. I only put a thin bead of epoxy on the edges of the wedges (fun to say) and a thin line on the fin/wedge joint. No need for anything more. If I were to do it again, and I plan on doing just that, I will build it with wood glue and no epoxy at all. I know it looks weird and you only get one shot at building it but trust the design, it works really well.

Yours has a benefit mine doesn't in the form of the 1/4" fins. Mine are the old school 3/16". Glad to see the thicker fins actually because the next one I plan on building will have a 54mm motor mount for K's. The only non-stock mod I will do is add a short section of coupler aft of the centering ring to reinforce the but edge of the body tube. My current Magg has bit of road rash back there. One thing to note, the Magg is a "ride it hard and put it up wet" kinda rocket. It's easy to prep and fun to fly. Good luck with yours!

I have built two Minie-Maggs. I added about 6 oz of weight to the nose on both of them because the Minie-Magg is just barely stable otherwise. I flew them on H, I, and J motors. I never had any problems with the fin attachment method. Just be sure to use enough epoxy on the inside parts.

Fiberglass is a good idea. My first Minie-Magg was lost and then my second Minie-Magg only lasted a few flights before getting zippered. Then my Mega Der Red Max was also destroyed by a zipper on it's first flight. After that I decided not to build ANY MORE CARDBOARD ROCKETS.

amell said:

Started on building a Minie Magg today. Was surprised to see the fin attachment method - I'm not overly keen on this method and I'm concerned about its resistance to lateral force on landing. It's done with wedges through plywood (see pic) and they are not attached to motor tube. What have others done here?

Some options:

Fins - lots of epoxy and chopped strand Mat for strength on the inside of the tube. Maybe some microfibres in the epoxy too if I have some left.

Thinking about fibreglassing the tube by taking the glassine off and putting a couple of wraps on so that the external fillets get a better bond. Only trouble with that is that it will add thickness to the tube and so the nosecone will no longer be completely flush on the top edge.

Other mod I will make to the kit is to have two lifting eye bolts in the upper bulkhead to help resist zippering forces.

I'm keen to not add too much weight as motors are expensive here in the UK but I'd like the option to be able to fly it on J motors on the odd occasion.

View attachment 281563

Click to expand...

Just use wood glue. You're not building a tank or are you?

liberal amount of wood glue.

The fin attachment method works better than you would think. LOC uses the same trick on even bigger rockets like the Warlock, Doorknob, and Bruiser.

Thanks for feedback all. Chewing it over. Quick build or fibreglassing - that's the choice. Undecided just yet. My choice will become apparent later in the build thread

On the topic of paint jobs. I am thinking that I quite like the look of the stock paint job. Printed the decals out and they look ok. It's not horrible is it?

Nathan said:

I have built two Minie-Maggs. .. my second Minie-Magg only lasted a few flights before getting zippered. Then my Mega Der Red Max was also destroyed by a zipper on it's first flight. After that I decided not to build ANY MORE CARDBOARD ROCKETS.

Click to expand...

The root cause of zippers is an incorrect delay. Fix that, and then over-building is not needed.

My circa 2001 stock Minie Magg did not even have the fin tabs. I had to repair the fins a few times. The cardboard got a little beat up, but worked just fine for 15 years of hard flying. I finally retired her this year after a friend gave me a new model.

Buckeye said:

The root cause of zippers is an incorrect delay. Fix that, and then over-building is not needed.

Click to expand...

+1. Or drag separation--which is also easily fixed.

+1 on the wood glue. It is a very strong bond for it.

amell said:

Thanks for feedback all. Chewing it over. Quick build or fibreglassing - that's the choice. Undecided just yet. My choice will become apparent later in the build thread

On the topic of paint jobs. I am thinking that I quite like the look of the stock paint job. Printed the decals out and they look ok. It's not horrible is it?

View attachment 281641

Click to expand...

It is a cool paint job. I've actually never seen one painted stock in person, but the picture looks good.

Buckeye said:

The root cause of zippers is an incorrect delay. Fix that, and then over-building is not needed...

Click to expand...

That wasn't the problem with my Minie-Magg. I was using an Archetype cable cutter. The descent speed when the main deployed was high enough to cause the recovery harness to tear about 2" into the cardboard airframe. Maybe a drogue would have prevented it.

I plan to reuse the nosecone from that Minie-Magg to build a fiberglass Minie-Magg clone with 75 mm motor mount.

I am building a Minie-Magg now and am going to use the Jolly Logic Chute Release with it.

I have an older Minie Magg that didn't have those fin tabs. I put a single layer of glass just on the fin area. This helps with keeping the fins from getting damaged on landing as I launched it a few times in a gravel pit. I put way too much nose weight in mine. However, I have flown it successfully on H, I and J motors. If I were building one now, I would put a 54mm motor mount in it at the minimum. I do plan to make another one with a 98mm mount so I can use coffee can K's in it. That one will get some special treatment. It will probably need that heavy nose cone.

Anyway, the Minie Magg is a fun kit stock or modified. I should paint mine some day.
Enjoy the kit!

amell said:

Thanks for feedback all. Chewing it over. Quick build or fibreglassing - that's the choice. Undecided just yet. My choice will become apparent later in the build thread

On the topic of paint jobs. I am thinking that I quite like the look of the stock paint job. Printed the decals out and they look ok. It's not horrible is it?

View attachment 281641

Click to expand...

Subscribed - and looking forward to seeing it fly! IMHO any colour scheme with either blue or red is a good colour scheme for greenfield launch/landing sites for visibility purposes, so that stock black roll pattern / blue NC both looks good and has practical benefits.. if I was being really picky I'd suggest adding another stripe on the fins/aft section, like the one around the AF just in front of the fin roots.. but that's just me.

I centitled back in 1997 with a mini-magg. The final attachment method is even weaker than what you are showing. It is stock and now 19 years old and still flying without repairs. New paint, but no other repairs. Flown mostly on I161s.

Made a bit more progress on this today. I decided not to fibreglass this in the end as I wanted to keep it light.

On reflection I think I would in future do one wrap of fibreglass to get rid of spirals in the tube as it took somewhat longer than I expected.

Test fit of the fins after priming and smoothing the tube.



Spirals in the tube. Some wood filler took care of these. Took a fair while to get it smooth.



Gluing the fins in with west system 105/205 mixed with 406 colloidal silica to thicken it up (Araldite consistency)



Put two lifting eye bolts in as I didn't think much of the supplied eyebolt which was cheap and only on one side. This will give me the ability to have two connection points for a short loop of thick Kevlar tape to help prevent zippering as the zipper load is distributed around the tube edge. The shock cord will attach to the Kevlar tape just outside the tube.



Filleting and painting comes next!

A progress update. Had my hands full with work so things have been a bit slow.

The motor mount tube was replaced with 38mm PML tube as I prefer this to the LOC cardboard. It fit nicely with a little sanding of the holes, made it slightly longer too. Departed from the instructions here. Installed aft centering ring flush with the bottom of the fin tabs and epoxied it in place from inside. I also epoxied in a small wood block to serve as an anchor for the rail button bolt.

When the epoxy was set I installed the motor mount tube and the bulkhead centering ring in one go.

I then gave the inside of the body tube a thin coat of epoxy to make ejecta clean up easy.



Next step was to get the surface of the body tube smooth. I hate spirals. Decided to give the whole outside of the body a coat of epoxy laminating resin to get it nice and smooth and to stiffen the tube up too.

Prime and sand, prime and sand (3 times now) good enough finish. Now for a coat of white primer before putting the white gloss on...

Thinking I won't do any fillets for this one. Somehow it looks better without the fillets...

Good progress. Are you aiming to fly it next Sunday at EARS (weather permitting!)..?

Quite possibly.... If paint dries in time

Good stuff - here's hoping! My current build won't be ready but I'm aiming to bring the Loc Fantom over.

amell said:

Thinking I won't do any fillets for this one. Somehow it looks better without the fillets...

Click to expand...

I'm doing fillets on mine as we speak. I wish I would have made them smaller as I agree with you, it looks good without them. And the construction should be sufficiently strong without fillets for the forces this bird will encounter.

Some more progress this week. White gloss coat is on. Been printing the decals onto decal paper with my inkjet. I've been coating the decals with lacquer tonight and as a result feeling somewhat out of it. More ventilation needed I think
Hope to get the decals on tomorrow evening. This is my second attempt as I didn't have enough lacquer on the test page I did. Fingers crossed.

It was close to the wire. Decals applied yesterday afternoon and a coat of lacquer at 1am. This morning it has dried sufficiently. She should fly on her maiden voyage today. I hereby christen this rocket "Magginator".

Take vid of the flight!

No vid unfortunately but here is a photo of the launch. Took it nice and easy on a 2G Pro38 White thunder for this maiden. Flew nicely. The delay was slightly long compared to prediction so will take it down a second or two for next flights.

Very nice looking rocket. The chute is not bad either.

Launched it again today in the Midlands. Upped from 2G to a 3G white thunder I408. Cocked hard right off the top of the rail and it wasn't windy. Wonder if that means it needs more nose weight. Thanks to Pete Barratt for the pics.

Nice boost. Was the rail clean? And how long of a rail was it?