Scale Redstone missile

[astronboy]

I have been working on a BT-70 based scale Redstone missile fo some time, and have finally completed the boilerplate model to fly this weekend at our club launch.

This model is a challenge to build as the fins are rather small, and there is a large paper transition to deal with.

I have attached several pictures to show construction details:

BTW: Would there be any interest in this as a plan/pattern set along with decals for both the olive drab and various black/white test rounds? Please remember that the attached is a boilerplate, and is missing most scale details and decals.

Phred
I have att

 

[astronboy]

The first picture (above) is the BT-50 engine mount/stiffer tube with the BT-70 centering rings, along with the BT-60 recovery bay.

Below is a pic of the finished boilerplate. It sims to about 500' on a D12-5, and 1200' on an E30-7.

Ph

 

[powderburner]

That doesn't look very goony

 

[mx774]

"BTW: Would there be any interest in this as a plan/pattern set along with decals for both the olive drab and various black/white test rounds? Please remember that the attached is a boilerplate, and is missing most scale details and decals."

I'm interested...

 

[astronboy]

SNIP
<hmmmm
That doesn't look very goony>

Nope... Although I love the Goonys, I also love scale models, so I am trying to spread Excelsior's horizons a bit.

As long as the weather holds, I will fly this puppy tomorrow on a D12, and report back.

Phred

 

[sandman]

Phred,

That looks pretty darn good for a "boiler plate" version.

 

[astronboy]

Well... the guts are all pretty good, but I am not happy with the finish. (I did a ruch job in order to fly it this weekend)

I also have not added any scale details any smaller than the second stage finlets. These will be a combo of some balsa details and some decals.

Finally, I intend to create some decals for the test rounds, but getting the proper arc for the bands around the transition has not been easy.....

This model required 8 grams of noseweight. I hate adding noseweight, but I knew that it would not fly without at least a D. Such are the difficulties of scale modeling....

Ph

 

[powderburner]

Originally posted by astronboy
I hate adding noseweight, but I knew that it would not fly without at least a D.

I hate adding ballast too but in this case (especially with scale fins) the design would make you suspect the need for ballast before you even get started.

Yes, I would be interested in a plan/pattern set, even if it doesn't look goony.

 

[fehskens]

I'm working up a BT-60 Redstone (1:42.7), using the nose cone from the BMS/Alway Astrobee 1500 kit. It turns out the Redstone and Astrobee nose cone profiles are remarkably similar, certainly good enough for "eyeball" sport scale. If this works out, I'll ask Bill to turn me some more accurate Redstone nosecones (including that long transition). The main issue is stability, as the fins are quite small, requiring a healthy wad of lead shot ballast in the nose. A Rocksim model with scale dimensioned fins and 2 oz. of ballast claims to be stable. IIRC, a D12 lobs this almost 1000 feet.

I am considering laminating the fins, using .4mm or 1/64" (.67" scale) plywood (on a 1/8" core) for the outer layers and to form the leading edge wedge. This would allow the tip vanes (4" thick on the real thing) to be slightly thinner than the main fin (6" thick on the real thing), for a more scale effect. I'll still have to sand the leading edge wedge on the tip vanes.

len.

 

[Bill]

Originally posted by fehskens
I'm working up a BT-60 Redstone (1:42.7), using the nose cone from the BMS/Alway Astrobee 1500 kit. It turns out the Redstone and Astrobee nose cone profiles are remarkably similar, certainly good enough for "eyeball" sport scale. If this works out, I'll ask Bill to turn me some more accurate Redstone nosecones (including that long transition). The main issue is stability, as the fins are quite small, requiring a healthy wad of lead shot ballast in the nose. A Rocksim model with scale dimensioned fins and 2 oz. of ballast claims to be stable. IIRC, a D12 lobs this almost 1000 feet.

I am considering laminating the fins, using .4mm or 1/64" (.67" scale) plywood (on a 1/8" core) for the outer layers and to form the leading edge wedge. This would allow the tip vanes (4" thick on the real thing) to be slightly thinner than the main fin (6" thick on the real thing), for a more scale effect. I'll still have to sand the leading edge wedge on the tip vanes.

I would suggest looking at the plans for the old Estes Mercury Redstone K-41 at the JimZ site. This kit featured intricately built-up fins each containing five parts. I did not do such a good job on them in my previous life, but appreciated how nice it could look at the hands of a craftsman.

If you can find a display vehicle to examine in person, I strongly recommend seeing it. There is nothing like inspecting those unique fins up close to gain an insight on how to accurately model them.

I am considering building one based on an ST-20 tube to go along with the 1/35 Mercury Redstone and Jupiter-C (Juno 1). I plan to use a 1/32" ply center with balsa laminated on both faces, thicker stock for the main fins, thinner for the vanes. The top cone will be a BMS custom sized for a Quest 40mm tube, with a cardstock shroud for the transition.


Bill

 

[astronboy]

I flew the Redstone today on a D12-5. Liftoff was sweet, and thelaunch was nice and straight. I lost one fin tab upon landing. I had a 12" hemispherical parachite instead of an 18" parasheet, and the 12" chute was just not enough...

Here is a pic on the pad just before liftoff:

Phred

 

[astronboy]

And here is a lift-off shot:

 

[Stymye]

Phred , will you be attempting the Wresat decals? I have a Bt-70 model complete, but needs decals.

 

[astronboy]

That is part of my evil plan, YES!!

PM me via TRF PM.

PH

 

[gerbs4me]

what is a boiler plate?

 

[Silverleaf]

Boilerplating is the practice of flight-testing a non-detailed model to prove its flightworthiness.

The term is based upon similar practice in the aerospace industry.

Certainly with Rocksim, testing your rocket designs is made easier, BUT the greatest difficulty that people have with scratchbuilt/new designs and even scale designs is building and flying an unfamiliar model. So:

While it takes some extra effort and dollars to build two models, boilerplating and practice flying are necessary to guarantee success.

It is the only sure way to know that your model will fly as you expect it to.

Try to make the boilerplate as close as practical (in a functional sense) to the model you intend to build: use the same motor(s), recovery system, mass, and CG location.

Repeated boilerplate flights also help to practice unusual recovery or launch techniques and may provide ideas for improvements to the design of your rocket.

Cheers,

 

[Stymye]

a model built for testing, stability, motor selection, and general tweaking usually without out the finished details , paint,.ect.... basically something built prior to commiting to the final design

edit*sorry silverleaf ,I didn't see your post before I posted.

 

[gerbs4me]

oh ok, thanks for sharing that info

 

[astronboy]

Even with Rocism (which I used to design this bird), I am just not comfortable with some models, esp those that require a hunk of noseweight for rocsim to say that they are stable.

I just wanted to be sure that this puppy would fly. I learned this the hard way by building a few detailed, and highly finished scale models, only to end up with a up with something with very poor flying characteristics. (IE: they have so much noseweight, that they fly at very low altidudes.)

Another reason that I decided to boilerplate this model, is that I have not seen any other scale models of the Redstome missile, which suprises me. I find it to be an interesting and significant design. Why is this not a popular scale model? Is it the long transition, or the small-ish fins...? I have determined that it is the transition.

Phred

 

[dtomko]

Fred,
Beautiful work! I don't know either why it isn't more popular, but the transition is a good reason. You would think that with the Centuri/Estes Merc Redstones being available for so long this would have been a natural conversion project.
Drew Tomko

 

[astronboy]

<You would think that with the Centuri/Estes Merc Redstones being available for so long this would have been a natural conversion project.>

My thoughts exactly.

Based on this model however, my guess is that the conversion of that plastic engine/fin mount to 24mm may have something to do with it.

IMHO the Merc Redstone really needs D power.... so would any conversion.

Ph

 

[fehskens]

Bill suggests:

>I would suggest looking at the plans for the old Estes Mercury Redstone K-41 at the JimZ site. This kit featured intricately built-up fins each containing five parts. I did not do such a good job on them in my previous life, but appreciated how nice it could look at the hands of a craftsman.

I have the David Weeks Mercury Redstone drawings, and Peter Alway's Rockets of the Cold War booklet, so I have pretty good scale data for the fins. There's also Redstone data on the NARTS CD which is on the way.

>If you can find a display vehicle to examine in person, I strongly recommend seeing it. There is nothing like inspecting those unique fins up close to gain an insight on how to accurately model them.

I have seen the Mercury Redstone at the JSC in Houston, and have a fairly substantial collection of closeup photos of Redstone and Mercury Redstone tail sections. Actually, I think it's more challenging to get the variable radius fillet right than the overall fin planform and 3D shape. And all those darned rivets!

For this scale, I'm more interested in a sport scale version that mostly looks right rather than perfect detailing. I also have a 4" TMRC Juno 1 (Jupiter C) and a 4" Neubauer Mercury Redstone that I will lavish more attention to detail on. I will also probably convert one of the recent Estes Mercury Redstones (whose plastic fins are too large).

len.

 

[Fishhead]

Originally posted by gerbs4me
what is a boiler plate?

It keeps your food hot.

 

[Fishhead]

Originally posted by astronboy
BTW: Would there be any interest in this as a plan/pattern set along with decals for both the olive drab and various black/white test rounds?

Yeah, baby!

 

[Micromeister]

Great looking bird Fred!
Drew I think folks are a little timid toward long tapered cardstock transitions, or the big price tags for Large long turned nosecones.. or it may just be because it's an olive drab missile
Great history, but not the most pleasing to the eye model. I think that's why we don't see more of the military Army missiles, Honest John being the exception. I do think you have a great point, that big ol'e Estes Mercury-Redstone does make a great starting point for a conversion.

 

[jetra2]

VERY cool rocket, Fred. I always think it is interesting to see the old space launching vehicles in their old 'clothes' before they became a SLV. It's like a flashback times 2!

Jason

 

[CTimm]

Try this paint scheme....