Maxi Alpha III "E" mod planned - tips?

[Steve]

Mailman hasn't dropped it off yet, so I don't have it in front of me. I don't imagine it will be too difficult to lengthen the mmt enough for E's, but since this one uses plastic fins, I thought maybe there'd be something specific to this model to keep in mind. I did take note of the reviews at EMRR about dry-fitting the mmt before assembly, and adding epoxy fillets.
This rockets sure looks like it ought to be a good performer. I'm kinda surprised it isn't mentioned here more than it is. (Maybe I'll find out why after I get mine ) Thanks.

S..

 

[Darian Rachal]

I imagine it would really perform well on a composite E or one of the AT 24mm F engines. Do you plan to replace the chute with a nylon? I find the Estes chutes a little too large for my liking. I prefer a chute size just large enough to keep the rocket from being damaged.

 

[loopy]

I would suggest getting a stronger 24mm motor tube (LOC/Precision comes to mind - these motor tubes will handle the heat of SU and RMS 24mm loads. If you can't get one online, let me know) and build with CA and Epoxy, and coat the centering rings with epoxy to strengthen them. I would also suggest adding a length of kevlar to the shock cord, attaching it to the upper centering ring and long enough to clear the top of the body tube by a few inches. Tie a loop in the top of the leader so you can attach the regular shock cord to it, but make it detachable. This way, you can get a parachute protector and use it in several rockets - attatch it to the kevlar leader when you fly it, then take it off when you're done. You can use it in several rockets that way. Also on the leader, put several wraps of masking tape around the kevlar where it hits the body tube. Make it fairly thick, but somewhat loose with some give. This will help to prevent the kevlar from zippering the tube on a higher speed deployment. Finally, get a nylon parachute for it.

I've done these modifications on my Big Daddy, Phoenix, Executioner, and Prowler (bashed to 24mm) all with E length hooks. Seem to be doing pretty well!

Let us know how it works out!

Loopy

 

[Steve]

Originally posted by Darian Rachal
Do you plan to replace the chute with a nylon?

I do have an 18" nylon chute that I made a while back for my Silver comet (mainly just to see if I could operate the sewing machine) - and I've been using it for my Big Daddy and Super BB. No reason not to use it on a third rocket. (Unless I decide to fly more than one of them at the same time).

Originally posted by Loopy
I would suggest getting a stronger 24mm motor tube (LOC/Precision comes to mind - these motor tubes will handle the heat of SU and RMS 24mm loads.

I don't know what SU is, and I haven't gotten my feet wet yet as far as RMS (although, I'd really like to - just don't know enough particulars) - so I'll be using whatever Estes E's I can find, for now. Could I beef up a regular 24mm motor tube? CA?

and coat the centering rings with epoxy to strengthen them.

Great tip - hadn't thought of that!

I would also suggest adding a length of kevlar to the shock cord, attaching it to the upper centering ring and long enough to clear the top of the body tube by a few inches.

I've done this as a matter of course on all my rockets since I found these forums.

Thanks for the advice, I'll get some pics up as soon as I can.

S..

 

[Missileman]

SU means single use motor, although technically Estes motors are SU it usually refers to aerotech motors.
I would imagine a coat of epoxy on the outside of the current tube would strengthen it up a bit.
Either way I would expect that you will have some fantastic flights.

 

[Steve]

Thanks. Not to get too far off topic... but would you know of a good [online] source for AT motors? SU or RMS? I would really like to try out something non-Estes for a change.

S..

 

[Initiator001]

As has already been mentioned, use a heavier walled motor tube if you are going to be using composite motors.

My 1985-vintage Maxi-Alpha III flew for nearly 15 years before the motor tube wore out from the 'energetic' ejection charges from AeroTech E15s.

As for a good motor vendor, I recommend Discount Rocketry.

www.discountrocketry.com

I'm just a satisfied customer.

 

[Rob Fisher]

Definitely add some beefy fin fillets, cause those flimsy plastic fins like to break off easily! I set my maxi-alpha 3 up for an E mount about a month ago and it flies great! I always felt like it was under-powered on the D's.

 

[Steve]

Originally posted by Initiator001
As has already been mentioned, use a heavier walled motor tube if you are going to be using composite motors.

I thought about wrapping the stock tube with some of that 1/2" wide cloth tape - similar to what you might find in a first-aid kit. Maybe give it a coat of thin CA or even sanding sealer/wood hardener first. Anybody done anything similar? I kinda want to get started soon rather than to wait on getting a new tube through the mail. I'll check my local hobby shop first...

S..

 

[loopy]

the beefier ejection charges of the composite motors will destroy the motor tube from the inside out. If you don't want to wait, the only thing I can think is to coat the inside of the tube with epoxy or something above the level of the motor itself.

 

[powderburner]

I think that kit already comes with a 'retainer tube' that slips over the bottom of the MMT and holds the metal motor clip in place. This already effectively adds some reinforcement to the MMT. Do you need more?

If you want to add more thickness to the basic BT-50-sized motor mount assembly, why not use some scrap BT-50 split lengthwise to wrap around the outside? (apply glue thoroughly first, wrap with rubber bands, etc). This will be light, cheap, simple, and uses materials you probably already have. Or, if you do not want to leave a small gap between the edges of the outer tube layer, use some scrap BT-55 and cut out a slot so the wrapped layer closes completely. Be careful how much of this 'outer wrap' that you add, as it may interfere with sliding through the plastic centering rings included in the kit.

Another mod to think about if you are using the basic BT-50 MMT: you may want to add a layer of extra BT on the INSIDE of the MMT tube, forward of the motor face. Apply some glue to the inside of the basic BT-50, slip in the liner (work FAST), and don't forget to also coat the inside of the liner with CA or something. This is to protect against ejection charge damage in a location that will be difficult to reach after you finish assembly of the rocket. Now is your chance to slip in some extra insurance?