Sheri's Mercury Redstone

troj said:

Why not purchase a longer piece of motor mount? Assuming it's standard rocketry tubing....

-Kevin

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When you're right, you're right.

I feel like an idiot.

Situation normal.

The kit comes with a fin marking guide in the form or a wrap around that is cut out of the plan sheet. I cut it out and taped it in place and found that it fit perfectly. The marks for the four fins were transferred to the body tube and the guide was removed. An angle was then used to extend the lines from all the way to the rear to about 8 inches forward. A steel ruler was used to connect opposing lines across the after centering ring.

The instructions then had me offset the fin line by 1/16" to either side to accomodate the width of the fins. I know its a very minor point but I would have preferred to have the correct offset marked on the wrap around guide. This is purely my preference and is the first real thing I would change and its so minor that I feel silly even mentioning it. As I said, that would be MY prefference.

In any event, the offsets were marked and those lines were extended for the length of the fins. A fresh hobby knife and a steel rule were then used to score along the offset lines so that the vinyl coating could be removed in order to promote better adhesion of the fins.

The instruction made no mention of this next step but it is something I now do fairly routinely. I used a drill and made a series of perforations along the fin lines to aid in the formation of epoxy rivets. I did the same thing with a smaller bit along the root edge of the fins.

...

All four of the fins were mounted using 5 minute epoxy. A small batch was made for one fin and then a toothpick was used to trowel it into place along the BT. It was also used to force epoxy into the rivet holes. After that, it was a simple matter to press the fin into place, check for alignment and hold it in place until the epoxy set up stiff enough to hold on its own. The process was repeated for the other three fins.

I accidently got the forward centering ring a little too far forward so that the provided motor tube would not extend far enough; when it was inserted, in just bared touched both centering rings without enough overage to provide any support. Fortunately, I had a piece of LOC motor tubing sitting around for a project that has yet to begin and decided to canibalize it. I inserted it so that the front protruded just a bit from the forward ring and then marked the tube where it had a 1/2" clearance on the aft ring. I then made up a mandrell and cut it to length with a razor knife.

The resulting tube was slid into place and secured with more 5 minute epoxy.

JAL3 said:

The resulting tube was slid into place and secured with more 5 minute epoxy.

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Looking good there, you have provided me with some good insight. I am getting anxious so I might start my MR build in a couple of weeks. I need to get onto something else for awhile, I am still smarting over my Delta IV loss last Saturday....

Delta-IV said:

Looking good there, you have provided me with some good insight. I am getting anxious so I might start my MR build in a couple of weeks. I need to get onto something else for awhile, I am still smarting over my Delta IV loss last Saturday....

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Thanks.

I saw the posts on the loss and I feel for you. I can only imagine the amount of work that goes into making any of your deltas. I get bent out of shape even when I lose an RTF but to lose one that involved a lot of work is heartbreaking.

If there is one thing that surprized me most about this kit it was the instructions on filleting. I expected to fillet the fins with epoxy but the instructions said to used plain old white glue. I decided to follow the instructions to see how it would work out. I began laying in the fillets, letting them dry, rotating the rocket and doing it again.

The tower for the launch escape system is built up out of styrene tubing. Construction of the LES begins with taking the plan for one of the verticals and cutting it out to serve as a backdrop and template. The template was taped down securely and then three pieces of 3/16 styrene tubing were cut to length using the template as a guide.

The vertical struts were fabricate one at a time. A piece of the styrene cut to length was taped down on top of the template. Two further pieces of the 3/16 tubing were cut to the length of the "Y" at the bottom of the structure. These were then shaved on one end to achieve the desired angle. When they fit well enough, they too were taped into place on the template and the three pieces were joint with Plastruct solvent cement.

While the solvent was drying, a gusset plate to cover the joint was cut from .020 styrene. It too was then solvent welded into place over the joint. After letting it sit for a few minutes, the structure was taken up, more solvent applied to the opposite side and the entire procedure repeated twice more. I should have mentioned that while the piece was taped down, various depth marks were transfered to the tower struts with a felt tip.

The instructions indicated that the base of the tower was to be fabricated on a plywood ring. I looked in vain for such a piece of plywood. I did find a resin ring but the inner diameter of the ring was different than that shown on the plans. I contacted Sheri and she assured me that it was the correct part and was a result of a design change. Still unsure because of the amount of play left in the 1/8" space between the ring and the capsule, I contacted Sheri again and was reassured that this was correct.

When I built the tower for my kit, I went ahead and drilled all of the pieces at the attachment points. This will make the tower stronger and less likely to snap on contact.

The tower is a straight-forward easy build.....both times. The ring at the base is required to get over the detail on the capsule. The problem is how do you keep the tower attached when you fly. I didn't try the tape (as in the instructions), but it should work. I used little sheer pins that kept the tower secure and it broke on landing right where I thought it would.

One day my goal is to figure out how to make a flyable tower at any scale....... To me, that would be the same as a Nobel Prize in Physics....'cause thats what it's gonna take :y:

Bravo52 said:

When I built the tower for my kit, I went ahead and drilled all of the pieces at the attachment points. This will make the tower stronger and less likely to snap on contact.

The tower is a straight-forward easy build.....both times. The ring at the base is required to get over the detail on the capsule. The problem is how do you keep the tower attached when you fly. I didn't try the tape (as in the instructions), but it should work. I used little sheer pins that kept the tower secure and it broke on landing right where I thought it would.

One day my goal is to figure out how to make a flyable tower at any scale....... To me, that would be the same as a Nobel Prize in Physics....'cause thats what it's gonna take :y:

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The photo speaks a thousand words.

Isn't it a shame they don't teach geometric constructions in school any more? Around here, they don't even bother with the proofs.

As to the tower, I have not thought this far ahead but I would like the LES to be in place when it flies. Maybe a drop of epoxy on the bottom of the ring would keep it seated.

The resin disk has a bevel to it so it must be oriented correctly. I made sure the beveled side was up and then cut out the the template. I taped the template onto the upper surface of the disk and scrounged around until I found a 3/32" drill bit. Six holes were then drilled in the places indicated on the template.

With the six holes drilled, I test fitted the vertical struts of the LES tower but did not glue them at this time, even though such was given as the step in the instruction. I wanted to make sure about the fit at the other end first.

The upper disk of the LES tower is made of plywood. I cut out its template, taped it into place and drilled the three holes it calls for.

The disk was then slid into place at the upper end of the assembly. Since things seemed to fit, both ends were secured with CA.

The horizontal members of the LES trusses are made from 1/16" styrene tubing. Using the plan as a guide for length, I cut the three upper horizontals. I placed them singly at the marks made earlier doing one side at a time and using Plasturct solvent weld. I let on side dry and then brushed the other side with a generous amount and squeezed it into place between the uprights. Since there was a bit of bowing, I used cellophane tape to hold the structure tight as it dried.

The next day, I peeled off the tape and inspected the results. It was a start.

Since the first one worked out, I got started on the second seriies of horizontal members. I cut three pieces of tubing from the plan and the solvent welded them into place, using a little tape to hold the joints closed. They too came out fine.

While the solvent welds on the LES tower were hardening up, I got to work on the Triple Mini Motor. It too was fabricated for styrene tubing. 3 lengths of 3/4" long by 1/16" tubing were cut to length specified on the plans. A 3/16" piece and a 1/4" piece were also cut.

The 3 pieves of 1/16" tubing were then bundled together and slid inside of the 3/16" piece with 3/16" left protruding. They were fixed into place with solvent weld.

Once the three pieces were tacked into palce, a razor was used to separate them and bend the three small pieces out at a 30 degree angle. The softening from the Plastruct helped with this.

THis entire assembly was then slid into the short piece of 1/4" tubing that had been cut and solvent welded. THe butt end as gently sanded to keep everything straight.

The LES tower being dry by this point, was inverted and set on its cap. The Triple Mini assembly was then glued to the center of the base with CA making sure that the mini nozzles were rotated in such a way as to be centered on the LES truss panels.

I tried cutting the first set of diagonal struts from the plans but that did not work out too well. Each was just a bit too long. Fortunately, Sheri is extremely generous in the materials she packs. I recut the diagonals purposefully too long and then started trimming them to fit by a short snip at a time. When they seemed to be the right length, I shaved a bit on one side of the end to give a bit of a miter and then put it in place with tweezers and Plastruct.