Maximus Icarus Clusterus

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Feb 21, 2009
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I am looking for some Ideas or suggestions on how best to complete my next project.
This is an upscale Maxi Icarus powered by a 3x 29mm Cluster.
The goal is to use some form of dual Deployment, Fly high as possible and not take the fins off in the process. :D

Parts aquired so far, from PML:

3" Intellicone - (I was trying to think of a way to incorporate this as part of dual deployment).
3" x 36" Phenolic body tube.
1.1"(29mm) x 36" Phenolic motor tube.
3 - 3 x 29mm Cluster centering rings.
3" Coupler/Bulkhead Assembly.
3 - .125" G10 Fins Custom cut by PML :) to 2x Maxi Icarus dimensions.
3" x 12" Clear acrylic tubing from Mcmaster Carr.

1st Question, Motor tube length. I hope to use at some point 29mm/360 motors. Is it acceptable to make the tubes 12" long and allow the motor to extend beyond it and if not, how long should they be?

2nd, Is the high speed of these motors such that I should not use them with fins of such a large span. I realize the drag will be huge so they and the tube will be reinforced with carbon fiber.
I will build the fin can with carbon fiber. This mock up just shows the fin orientation, I thought that this would be the strongest way.
Wow - 3x29mm! Very nice Merican! Looks like some high quality parts laid out for this build.

I am nearly complete with my upscale. It's in primer white right now. It is tentatively scheduled to fly this weekend. I'll let you know how that paint brush clear tubing holds up. First flight might be on something easy like a G40.

Keep us posted.
How much was the clear Tubing?

That SCREAMS Night Launch!

What do you plan for motor retention?
Hey Eugene, I've been keeping tabs on your thread trying to steal ideas ;) Cant wait to see launch pics. looks like I may not get to fly mine until spring.

Since I have your ear, do you think 29mm / 360 Aerotech motors are "too much" for these fins?

Hey Karl, I was thinking the same thing about a night launch, I'm toying with the idea of installing RC style strobe lights in the paload bay.

I found the Acrylic Tubing at McMaster Carr Search for Part #8486K367 Clear Cast Acrylic Hollow Rod 3-1/4" OD X 3" ID, 1' Length $14.64

The I.D. was close I need to hone it out .015"
The O.D. is .100" over so I will be tapering the nosecone end back about 2" then try and buff it out.

For motor retention I was thinking of embedding a modified 1/4 -20 threaded coupling in the center of the tubes then make a clip (read washer) to catch all 3 engines.

The wall thickness of the clear tube sounds like it is more than enough to withstand 3 29mm motors.

Your motor retension idea sounds solid.

This thread is giving me ideas on a 2X upscale of a Custom "Landviper"

Originally posted by Merican
Hey Eugene, I've been keeping tabs on your thread trying to steal ideas ;) Cant wait to see launch pics. looks like I may not get to fly mine until spring.

Since I have your ear, do you think 29mm / 360 Aerotech motors are "too much" for these fins?

For motor retention I was thinking of embedding a modified 1/4 -20 threaded coupling in the center of the tubes then make a clip (read washer) to catch all 3 engines.

Unfortunately the MAXI-Icarus will fly in primer colors this weekend. I was hoping to have it "dressed" by Saturday, but the imperfections in the tubing are too great to just overlook. I'm sure the launch pics will be cool either way! Regardless, it'll be a good test to see if the tubing holds up. (I think I mentioned it before.)

My experience in HPR is very limited - and limited to plywood usage only - but I would venture to guess that you will be ok with with the 29/360 motors. If in doubt, check out the Gates Bros. rockets - - those dudes use some G-10 for some CRAZY rockets. I think you'll be OK.

The retention idea sounds good. I think a lot of people use brass inserts or something similar to what you're describing in LOC rockets with clustered 29mm tubes.

Hopefully I'll have some new pictures up by Friday. (I just got a replacement motherboard for my PC. The old one was damaged by power outages/surges during this last hurricane.)
I have cleared the first hurdle. The clear tubing measured 2.980" I.D. / 3.235" O.D.
After some rather futile attempts at "honing" using various types of flapper wheels, I decided to take the tube for a ride out to my friend's small engine shop. Looking things over I quickly came up with a way to mount it in his vertical boring machine. I expected the worst but the acrylic machined very well. We opened it up to 2.995" on the nose cone end and 3.000" on the coupling end. The fit is perfect
The O.D. was a little more involved. I setup a guide on the disk sander similar to beveling fins, it wasn't pretty but it worked. Next I used a scotch brite flapper wheel to clean it up then tried to buff out the rest. An hour later it was looking ok but it was wavy. I ran down to Ace and picked up some sand paper and started over. I had some 320 grit disks for my orbital sander so I used one of these to start. The felt backing on the disk makes it stiff enough to arc around the tube taking of the high spots eliminating the waves, I was ecstatic. I followed up with 400, 600, 800 and 1500 wet sanding then another hour of buffing :( .

It's not perfect but for buffing acrylic for the 1st time I'm not complaining.
It looks like you buffed the O.D. down of the entire tube.

At least that is what it looks like to me...

That must of been quite a chore!
The taper is 2 1/2" long same lenght as the bore.
looking at the top of the 1st pic you can see it against the paper inside the tube.
After a construction period that dragged on most of last winter I finally decided to paint her up last month. I was going to wait to post launch pics at the same time but seems that the weather or other events have kept me grounded the entire summer. If all goes well I'll get my L1 cert this weekend with my "Navy Strike" and then give the Maximus Icarus Clusterus a go.

I had intended to post as construction went along but as this was my first scratch build I thought I would save myself the embarrassment. Lets suffice it to say that this is built like "a brick outhouse".;)

Sorry no close-ups, my painting skills are severely lacking
Icarus w/ Navy Strike
Here's a look at the "business" end for you perv's out there.
The motor mounts will accommodate 29/360's, I've been kicking around Ideas for dual deploy.

First flight will be 3 G64's (80 lbs thrust 56% of a I), one will be an 8 second delay, the others longer to minimize stress on the advanced motor retention mechanism :p .

Rocksim predicts a max Velocity of 360fps, Altitude of1800 feet and a long walk.
I've been considering a similar project, only mine will be smaller - I'll upscale to a BT70 (2.217") and use a 3x24 mm cluster mount.

Looks great! Can't wait to see launch pics!
Awesome job! I love me a cluster...those G64's are going to give it quite a ride. I flew a (2) G64W cluster a couple of months ago in my 4-29SS, and it really got up there. The G64W is, hands down, my favorite load for the 29/40-120 case.


Where'd you get the two 29/40-120 cases with black aft closures? Are they Monster Motors? Or are they just HPR cases you used to fill the holes? I doubt that considering the aft closures have the motor hook notches, but, you can see the backside of the forward closure for those motors, too, and those appear to be larger than those of the 29/40-120. Just wondering...

Again...great job!
Thanks for the comments Marv. The two black ones are 29/40-120 Monster Motors that I purchased from Whats up Hobbies (great price). I wish Monster Motors had come out before I bought the AT case. I figured by buying all three it would speed up the prep time on launch weekends. I like the G64 alot also, I flew the Navy Strike on it a was impressed, nice sound to them.
Updated Rocksim

I didn't load every mass object individualy. I cheated and measured the center of gravity and weighed it.
A note about the weight in the rocksim I used this project as a learning experiance and as such did some things that are unnecessary. The body is glassed using the sock and heat shrink tape method. I used 4 center rings and the internal fillets are reinforced with chopped carbon. needless to say this rocket should take a very nice core sample.

Also I used an entire can of white Krylon though a lot was sanded off and the graphics, such as they are, were masked and painted the Estes logo was a... umm... pain, The Maxi Icarus graphic is beyond my skill level so it will have to wait.