THE COMANCHE 3

  The Arizona Rocketry Team has selected its project for "Plaster Wars" which will be held October 4-7, 2007 at the Plaster City Launch Site.  This project will be managed in the same manner as all of our projects, with a twist.

"Krater" Ken is still the Team Leader and will be over seeing "No-Chute" Roy who will be acting as the "Project Leader" for this build.  We will be documenting the build as always on this site.

The Comanche 3 will be a 7.65 X Up Scale that will be flown as a true three stage rocket.  The current plan calls for the following motors being used:

1st Stage - 3 x K1100T / 2nd Stage - 3 x K695R / 3rd Stage - 3 x K550W

LDRS proved to be a great trip for those that could make it, but now it is time to start building the Comanche 3.  Construction Begins:

We have received the air frame tubing and couplers from Polecat Aerospace and have the foam on hand from Western Insulfoam.  The fiberglass sleeve is here and plenty of West System is on hand.

Today our goal is to get all of the air frame tubing glassed.  We need a total of three 8' sections and two 4' sections.  Once that is done we will be making three 21" long tubes that will fit into the couplers (these will need to be a snug fit).  That will give us the "Inner Concentric Tubes" that we will need to ensure a good coupling between stages.

Some of the 7.5" tubing and couplers that will make up the Comanche 3.  On the right you see one of the 8' sections that will be glassed.

Each tube is covered with a layer of 9" heavy and 9" medimum weight fiberglass sleeve.

After they were wet out they were placed into the 100 degree oven for 18 hours to cure.  The oven is also known as the garage. After all of the tubes were glassed we started to work on the Inner Concentric Tubes.

Once the air frame sections were cut longer then they are needed Jay cut out about 3 inches of the tube.  I then mixed up some thickened resin while the others slide the cut air frame sections in to a cut to lenght coupler that was lined with wax paper.  Jacob then filled the cut line and laid in some 5.4 ounce glass and wet it out with the thickened resin.

The fruits of our labor (minus a 4' section)

Well we had a good build session.  While we were working on the fins we were discussing the flight profile.  Using the K1100's on the the first stage would seperate at about 150 feet.  For this reason we decided to change the motor combination. 

Apparently "Freshman" have a different defination of Working.

Sorry Ladies - He is spoken for

The first fin of each size was cut out and laid out so we could get an idea of the spacing we would need.  This allowed us to lay out the fin can slots.

Once we had the spacing calculated Jay and Jacob went to take care of some family business and Ken and I went to work slotting Fin Cans.  Since the fins on each stage are different in size, we could not set the slotting jig and zip out all nine slots.

That is ok, this gave both Ken and I a chance to get ichy!

The first stage fin can was cut to length and then the tube that we glassed for the second and third stage had to be cut.  We figured that the best way to do that was to turn Ken loose with the dermel.  He wanted to use the Sawz All but we talked him out of it!

The slotting jig that Jay made worked great - Self centering with built in opening for the spring clamps to hold the tube in place - built out of solid oak - what more could one ask for!

After Ken Had his fun I took a turn

After the Fin Cans were slotted we took a minute to see how things were shaping up.  This is what we found.

*hint - the top of this third stage is 77 7/8 inches tall*

We are going to have another build session on Monday to keep ourselves on schedule so I will post another update when I can.

Monday was another good day in the shop!.. Jay showed up with all of the fins cut and ready to go.  Jay had to trim the third stage fins a little and he did it in style.

We were able to get the Inner Concentric Tubes slotted.  These are slotted shorter than the slots in the Outer Fin Can.  This will act as a way to center the Inner Concentric Tube.

By time the session was over we have something that resembeled a rocket

On Saturday (August 18) we had another build session.  At the end of the day it did not look like much was done but we were all busy!

Well most of us - Again ladies he is taken !

Honestly we did get a lot of stuff done.  All of the Centering Rings are cut.  This includes the 3/4" centering rings that are being used as thrust rings in the first and second stages.  the forward centering ring in the the first and second stage along with both centering rings in the third stage are 1/2".  Additionally remember that teh second and third stages have the inner concentric rings.  For anyone that has made their own couplers, you know that it is very hard to get two of them identical..  For that reason each ring has to be cut specially for the location that is will be installed.

You can see the dry fit in the picture on the left.  On the right Jay works on routing one of the rings.

Jay and I got one of the bulkheads in place.  On the right Jacob is fitting another one.

At one point in time all of us were working - Three at one end of the shop and Ken taking pictures.  I was cutting the 75mm Motor Mount Tubes,  Jacob routing Centering Rings and Jay drilling the holes for the MMT's.

Ken did work - He did the lay up on the motor stand off's.  Due to space and wanting a parachute bay with out having to wrap the chute around the motors we designed them to hang about 3 inches.  After the lay up Ken cut them to length.

We will be working on Monday - time to take care of some of the electronics lay out finished so I can get the e-bays built.  Life and other plans are going to prevent a team build session next Saturday but we will again meet on next Monday, August 27th.

We have been busy, and life has slowed us down a little, but we are back at it and moving along nicely.  We have had a few build sessions on this beast and continue to make progress.  All of the fin cans are build and the fins installed.  This is not as easy as it sounds due to the coupling technique we are using.

The Inner Concentric Tubes (ICT's) have been slotted and the Motor Mount Tubes have been installed in the ICT's and the entire sub assembly has been mounted into the fin can.  The fin tabs were notched so they provide centering to the MMT's and ICT's.

The fins were "primed" with slow cure epoxy and then a generous amount of thickened epoxy was spread onto each fin.  Once lathered up with epoxy the fin was inserted into the fin can, providing a nice fillet. After all the fins were in they were held in place for 36 hours using straps. 

Also during this time we made a bunch of bulkheads -boring pictures so I am not including them!

This past Saturday we ran in to a few problems.  We had more Bulkheads to cut for the altimeter bays and electronics sleds and I was not able to keep the router set properly.  I would set it for the size I needed and the bulkhead would come out 1/4" too small!!!!  We found that the bushings were gone and it had to be replaced.  Time for a new Porter Cable!

Since there were several things going on, I made the decision that we would not glass the fins tip to tip.  They seem plenty strong and we are not going supersonic with this flight.  The Rocket Rage Chutes should bring it down nice and slow.  We did get some rocket building done.

I was able to get the couplers notched for the fins.  This is how we are going to get a good coupling with the limited space we have in the fin cans.  This technique will provide good coupling and also provide a tight fit to keep things in line under thrust.  "Elvis" likes to keep things clean - and NO he does not sing while he is cleaning !

Jacob was measuring the distance between the fons so we could slot the coupler

NOT SURE WHERE THE REST OF THIS PAGE WENT BUT I WILL REBUILD IT SOON