Scratchbuiliding a Mercury Redstone

Perhaps I should be a little more precise and say this project will be flight MR-3 ("FREEDOM 7"). There is some capsule variation between the capsule used on Shepherd's flight as compared to Grissom's flight.

Anyway, I have been thinking about a scratch build for years. In my mind, the Mercury Redstone flights are iconic both in their design and place in history.



Greg

The airframe I am planning on is 2.60". It's not too big and not too small.

The time frame is ... long. I'm hoping for less than two years. There will be parts that are easy and parts that will be relatively hard to fabricate. I hope to have fun along the way, and perhaps learn a thing or two. I plan on making it as true to scale as my OCD self will allow, and still maintain my sanity.

The first thing I plan to do is the hard thing: the Mercury Capsule followed by the escape tower. This is the "crown jewel" of the rocket.

As a test, I plan to mill a section of the capsule and see how it looks. It looks fine on the computer screen, but getting it into the real world will be a bit of a challenge.



Greg

Subscribed, long term subscribed.

Subscribed as well. Been wanting to do one of these myself.

As far as propulsion, I am going for 29mm. Since I am going with scale fins, the nose will be heavy and I will need the corresponding punch off the pad. My mindsim thinks that an AT E28T or F40W will do nicely, even though I have no idea what the launch mass will be yet (400 to 799 grams?). So this is going to be in MPR realm.

As far as the reference material I plan on using, I will be relying heavily on David Week's scale data from RealSpace Models.



The plans are extremely helpful and just plain cool to look at and used it almost exclusively on my 3D capsule build on this link.



Greg

this is going to be awesome!!!!

First thing I had to do was make some milling stock. I'm going with MDF. If I make a mistake with that material, it's ok since it's relatively inexpensive.

Greg

op: I'm in.

Before milling the plate, I decked the surface to insure both planes were perpendicular to each other. The milling stock has an OD of 1.75" and a thickness of 0.75". That is a bit oversized for the need.

Here it is right off the mill:



The center hole is sized to self-tap (by hand) 1/4" steel all-thread. The off center hole is 1/8" to accept a stainless steel pin to help with plate alignment.

The "before" milling mass:



The next thing will be to chuck it up and hopefully after a few hours it will look like a section of the Mercury capsule. I've never done "A" axis milling before. So I could easily trash this part by making a "rookie mistake".

Greg

I had a delay in progress that I couldn't find the adapter from the rotary table to the 4-jaw chuck. Last night I was able to locate it and installed the rest of the hardware. I may have to tram the rod by hand, as I of yet have no indicator and related hardware. That though is a minor problem compared with the next one.

The code to run the mill on the software said the milling operation would take 45 minutes, but the software on the mill said it would take 16.5 hours to run! So I need to resolve this issue before I place it on the mill. Hopefully I'll get an answer soon so I can progress.

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More Project Mercury stuff, with some footage I hadn't seen before.

[YOUTUBE]a6gU0WYTIN4[/YOUTUBE]

Greg

Wow very cool and amazing the complexity. Makes u want to build one!

I was able to sort out the speed issue, and I got the runout to a barely acceptable level (makes me wish for a mentor on these things). The results were mixed. Generally, things worked like they were supposed to, but there appear to be errors in the cuts. This could be either software or because the method I chose to secure the workpiece to the all-thread did not work as well as I hoped. This is all part of the learning curve on A-axis milling. A tad harder to secure a rotating workpiece.

Greg

Any further work on this project Greg?

rharshberger said:

Any further work on this project Greg?

Click to expand...

No. The current project that I am focused on is the av bay for my Ascender (link). One of the goals from many years ago that I set for myself was to have a successful DD flight. I am very close to realizing that goal, so I want to bring that to the finish line.

Regarding this project, I have rethought this and I think the best thing to do is have it 3D printed. But it's going to have to wait until funds become available.

I need to work on the escape tower as well. There is a lot of detail on that.

If I am happy with the results of the 3D printing (and if there is sufficient interest), I might do a limited production run to sell to others. The rest of the Merc Redstone is easy by comparison. I'm kicking around making the variant with the long window so it can be used for "Liberty Bell 7" and the Mercury Atlas flights.

At the end of the day I want something that will not just look good on the pad, but look good on display.

So while it is dormant for now, it is not forgotten.

Greg

I am getting my parts together to do a scale version of Freedom 7 Mercury Redstone, and a as yet undetermined flight version of the Mercury Atlas. The capsules were 3D printed by Boyce Aerospace Hobbies on in 1/17.5 and one in 1/21.8 scale. As I was perusing threads on scale building the Project Mercury rockets I came across this thread again. Thanks for the reply.

No problem.

I hope you have a build thread, as I would want to check it out.

Greg

There will definitely be a build thread (or two).

I did open the file up to look at it again. While open I did another rendering.



Greg