Estes Jupiter C

[A Fish Named Wallyum]

I picked this up a few years ago, but I've only recently decided to start it. Anyone build one of these in the past? How durable is the satellite section during flight? Would I be better off allowing it to be removed before flight? Anything I should be on the lookout for during the build? I built the K-41 Mercury Redstone back in 1978, so the fins on this project are going to be a major league blast from the past. (I've got a nose cone from an original K-41 kit, so that will also get built this winter. These fins will be practice.) :cool:

[tbzep]

I picked this up a few years ago, but I've only recently decided to start it. Anyone build one of these in the past? How durable is the satellite section during flight? Would I be better off allowing it to be removed before flight? Anything I should be on the lookout for during the build? I built the K-41 Mercury Redstone back in 1978, so the fins on this project are going to be a major league blast from the past. (I've got a nose cone from an original K-41 kit, so that will also get built this winter. These fins will be practice.) :cool:

I've had one for probably 10 years, give or take a decade. :D

I flew it a bunch of times without breaking the satellite. The satellite finally broke when my wife ran into the freezer where it was sitting waiting to be loaded into my truck. It fell off and snapped when it hit the concrete garage floor.

[CPMcGraw]

I picked this up a few years ago, but I've only recently decided to start it. Anyone build one of these in the past? How durable is the satellite section during flight? Would I be better off allowing it to be removed before flight? Anything I should be on the lookout for during the build? I built the K-41 Mercury Redstone back in 1978, so the fins on this project are going to be a major league blast from the past. (I've got a nose cone from an original K-41 kit, so that will also get built this winter. These fins will be practice.) :cool:

I bought one back in '90, but never built it. Still got the transition out in a shop... somewhere...

The instructions say to remove the Explorer 1 probe for flight; the kit has an injection-molded plastic rendition with some nozzle detail, so it was intended to be displayable separately. My thoughts would be to build a second Explorer using a dowel, and permanently attaching it into the top boost canister. Keep the plastic version safe...

Those fins were the main reason I never finished building mine. They're laminated balsa, and the balsa in the kit was of less-than-optimum quality to begin with. Reminded me of what used to come in Carl Goldberg model aircraft kits of the late '60s and '70s -- raunchy crumbly over-dried stuff with an orange-ish tint to it. Warped badly when you touch it with glue, even ACC...

These really needed to be vacu-formed plastic skins over a balsa core, to achieve the wedge-shaped leading edges of the prototype...

[A Fish Named Wallyum]

I bought one back in '90, but never built it. Still got the transition out in a shop... somewhere.

What transition? Mine is just a solid BT-70.

The instructions say to remove the Explorer 1 probe for flight; the kit has an injection-molded plastic rendition with some nozzle detail, so it was intended to be displayable separately. My thoughts would be to build a second Explorer using a dowel, and permanently attaching it into the top boost canister. Keep the plastic version safe...

Well, I haven't actually GOTTEN to the step where I READ the instructions yet. That comes after I screw something up. :rolleyes:
I like the idea of the permanent satellite. I need to go dowel shopping for that Mercury Redstone tower piece anyway.

[A Fish Named Wallyum]

I've had one for probably 10 years, give or take a decade. :D

I flew it a bunch of times without breaking the satellite. The satellite finally broke when my wife ran into the freezer where it was sitting waiting to be loaded into my truck. It fell off and snapped when it hit the concrete garage floor.

Wives. Sheesh. ;)

[tbzep]

What transition? Mine is just a solid BT-70.




The nosecone looks like a transition section between the main body and the rotating can at the top.

[CPMcGraw]

What transition? Mine is just a solid BT-70.

I call it a transition, but TBZEP is correct in calling it a nosecone; it's the whole upper section of the rocket, including the spin-up canister. The Explorer 1 piece slip-fits into a tunnel down the center of the canister, with just the upper portion poking out. Mine was a single piece of blow-molded (IIRC) plastic for the lower portion, with two or three pieces of injection-molded plastic being glued together to form the canister. They were harder than the transition, at any rate. This subassembly gets glued to the top of the transition...

[A Fish Named Wallyum]

Ahh. Gotcha. I just figured this was the nose cone since the recovery system hooked into it. I can see where it would be a transition.

[tbzep]

Are you going to modify the fins to be a little more scale? The stabilizers are way too big and look funny sitting beside my Mercury Redstone. It's a shorter rocket than the MR, but a little extra nose weight might compensate.

[A Fish Named Wallyum]

Are you going to modify the fins to be a little more scale? The stabilizers are way too big and look funny sitting beside my Mercury Redstone. It's a shorter rocket than the MR, but a little extra nose weight might compensate.

I wasn't planning to. Are the fins the same on both models?

[Royatl]

I built mine in 1988. The Explorer lasted through many flights, but was sheared off in a ground accident. The suggestion of replacing it with a dowel sounds like a good one. If it ever breaks off you can use a hand drill to ream out the old one and replace it.

The fins require some carving/sanding, but if you do it right, they look just as good as or better than the plastic fins on the latest version of the Mercury Redstone. The Estes Jupiter C was just the Centuri Mercury Redstone with a shorter, one-piece body and different nose, just as the real Jupiter C was just the Redstone with a different nose. The fins are larger than scale though. I've never seen anyone try making scale ones except with the old Estes BT60 kit, and numerous Hawk/Glencoe Jupiter C conversions. The Hawks tended to be iffy in any sort of wind, and flew better on B6 than on B4 or MPC B3.

[tbzep]

I wasn't planning to. Are the fins the same on both models?

The MR has fins that are closer to scale. It is a longer rocket so it doesn't need as much fin area.

[kurtschachner]

The MR has fins that are closer to scale. It is a longer rocket so it doesn't need as much fin area.

Well, the fins supplied with the Estes kit aren't scale in size, but neither are they really scale in shape either. There's more detail to them than Estes cut with their die. I did redraw some better fins for my model based on ROTW, but they turned out hard to cut so I gave up.

On another point, doing the double lamination thing is good for a couple of reasons. One is that it gives you a semi-rigid center point to sand against when making the knife edge, plus it is easier to cut a thinner piece of bass or balsa than the thicker stock.

[tbzep]

Well, the fins supplied with the Estes kit aren't scale in size, but neither are they really scale in shape either. There's more detail to them than Estes cut with their die. I did redraw some better fins for my model based on ROTW, but they turned out hard to cut so I gave up.

I know that neither the Jupiter-C nor the Mercury Redstone are scale, but the Mercury Redstone's fin looks closer if you are just eyeballing it. You're right, they aren't truly scale, but the rest of the kit ain't exactly a 100% accurate reproduction either.

I have both models sitting beside each other right now, but normally I keep them separated. I did a good job building them, but they don't look good together because Estes made two different sets of fins for the kits even though they are the same "1:35 scale". It wouldn't take that much effort to make the Jupiter-C look more like the Mercury Redstone, IMHO.

[Patriot Pilot]

According to Rockets of The World both rockets had the same fins. The Redstone was 92' longer. Both had the same diameter. I can scale the fins if you would like. What is the OD of the body tube you are using?

[CPMcGraw]

I know that neither the Jupiter-C nor the Mercury Redstone are scale, but the Mercury Redstone's fin looks closer if you are just eyeballing it. You're right, they aren't truly scale, but the rest of the kit ain't exactly a 100% accurate reproduction either.

I have both models sitting beside each other right now, but normally I keep them separated. I did a good job building them, but they don't look good together because Estes made two different sets of fins for the kits even though they are the same "1:35 scale". It wouldn't take that much effort to make the Jupiter-C look more like the Mercury Redstone, IMHO.

Here's a link to an image on the web for (one of) the Explorer missions:

http://www.redstone.army.mil/history/archives/jupiter/jupiter_c_rs26_4mar58_05.jpg

The fin detail is grainy, but you can get some of the scale from it...

[tbzep]

I know exactly what the fins should be like. I've been to Huntsville and to the Cape and have plenty of photos of the Redstone boosters. The physical shape of the fins are identical for both the Mercury Redstone and the Jupiter-C. I have Alway's Rockets of the World, which also shows the fin dimensions. I have already built both kits, but didn't notice the ugly enlarged fins of the Jupiter-C until after it was completed and sitting beside my Mercury Redstone. I know the MR fins aren't scale either, but they look much better than the Jupiter-C fins.

I'm just saying that having both Estes models side by side looks goofy because not only are the fins not scale, they aren't even the same between the two models. I didn't want you guys to make the same mistake I did and build both kits in stock configuration.

I see three options for a good pair of Redstone based models for your display shelf. Any of these three remedies will make both kits much nicer to look at than if you build both of them stock. If you only have one of the kits and don't plan to build the other, don't worry with it.

1. Make both rockets with fins as close to scale as possible based on Alway's book or other scale data. Most importantly, the fins will be identical to each other so they will look good sitting side by side..

2. Keep the Mercury Redstone kit in stock configuration and make the Jupiter-C fins identical to the MR.

3. Keep the Jupiter-C in stock configuration and make the MR idental to the J-C.

[Patriot Pilot]

For those scale buffs the Estes version is scale in length and the smaller outboard square fins are scale, however the diagonal portion of the fins are 3/8" wider on the Estes than they should be. You could probably make them scale and play with it.

[A Fish Named Wallyum]

According to Rockets of The World both rockets had the same fins. The Redstone was 92' longer. Both had the same diameter. I can scale the fins if you would like. What is the OD of the body tube you are using?

It's a BT-70 kit.

[Patriot Pilot]

It's a BT-70 kit.

Yeah I know. I dug out my Redstone and crunched a few numbers.
I'll draw up a picture and send you the dimensions so if you want you can make them scale.
If not I can just waste my time anyway and add them to my grow cashe of useless information. :rolleyes:

[Patriot Pilot]

Heres what I got based on a BT-70.
Rechecked it to make sure so if I am wrong its only human. :D
The missing measurement is .666". You figure it out. ;)

[CPMcGraw]

Heres what I got based on a BT-70.
Rechecked it to make sure so if I am wrong its only human. :D
The missing measurement is .666". You figure it out. ;)

So, it's a real beast? :D

Curious measurement...


Here's what I measure for the most-recent release of the Mercury-Redstone (plastic fins)...

Root Edge -- 3.6"; the lower part of the under-skirt fin drops down 0.1" below the trailing edge of the outer fin. Matches well otherwise with PatriotPilot's drawing.

Outer Fin Tip Edge -- 1". Matches the drawing.

Outer Fin Span -- 0.75", or 50% wider than the drawing.

Inner Fin Span -- 0.90", or 80% wider than the drawing.

Under-skirt Span -- 0.40", which is 0.025" wider than the drawing.

Under-skirt Chord -- 0.90", or about 40% longer than the drawing.

With the exception of the increases in overall span, these fins look good enough for an SOS model, and they already have the leading edge bevel molded in. They have that prototype thickness, too. Maybe these fins would be a better starting point, if one could build the motor mount with more traditional non-plastic parts.

[A Fish Named Wallyum]

I've got the original fins here at work tonight, so I'll decide what I'm going to do after I see how they look glued together. (Monday is a notoriously slow night.)

[Tau Zero]

0.666" -- So, it's a real beast? :DOr a fraction (I mean, "decimal") thereof. :eek: :D ;) :cool:

--Jay


"Run for the hills/Run for your lives..."
--Iron Maiden

[tbzep]

Heres what I got based on a BT-70.
Rechecked it to make sure so if I am wrong its only human. :D
The missing measurement is .666". You figure it out. ;)

There's a problem with the drawing. The control surface wedge is shown going all the way up to the angled main fin component. The wedge is much shorter for the Redstone booster. Your drawing of the wedge looks more like what they've done with the Jupiter-C.

My numbers are slightly different also. Click on image for numbers and a note on how the wedge is shorter than the main fin tip.

[Patriot Pilot]

Okay so I rounded the outside fin up to 1 inch instead of leaving it at .95 something and I didn't carry my mutiplier out past 3 digits . Fire me. :D :D :D

[tbzep]

Okay so I rounded the outside fin up to 1 inch instead of leaving it at .95 something and I didn't carry my mutiplier out past 3 digits . Fire me. :D :D :D

That wasn't my point, and I wasn't being nitpicky about the numbers. I just decided to include them when I ran the numbers for the control wedge and the fin tip. My point is that the wedge went all the way up to the leading edge of the fin in your drawing, but it doesn't come near it on the real thing.

My sole reason for posting to this thread the first time was to give Bill a head's up on the different look between the two Estes Redstone based kits so that he could modify one of them to look like the other for a nicer looking pair. I didn't intend it to be a scale expose. Some of you guys started throwing in scale numbers. :D

[A Fish Named Wallyum]

I have some pics of my own from the Smithsonian last year, but the Jupiter on display there isn't in a good position for detail photography, especially on a Saturday afternoon. :rolleyes: I appreciate all the data, but as long as it flies, I'll be happy. :cool:

[Patriot Pilot]

I just wanted to overwhelm Bill with numbers. I don't think he even knows what a scale is.
He's the english major here its like a second language to him. :D :D

[tbzep]

I just wanted to overwhelm Bill with numbers. I don't think he even knows what a scale is.
He's the english major here its like a second language to him. :D :D

LOL!

Bill, here is your multiple choice question.

Scale is

a. an inanimate object that ridicules me about my love handles..
b. what I do to get to the top of the "to build" pile.
c. a proportion used in dimensional relationship.
d. little nasty thingies all over those icky fish.

[A Fish Named Wallyum]

I just wanted to overwhelm Bill with numbers. I don't think he even knows what a scale is.
He's the english major here its like a second language to him. :D :D

HISTORY major, you anal carbuncle. :mad: I just took English for fun. :cool:

[A Fish Named Wallyum]

LOL!

Bill, here is your multiple choice question.

Scale is

a. an inanimate object that ridicules me about my love handles..
b. what I do to get to the top of the "to build" pile.
c. a proportion used in dimensional relationship.
d. little nasty thingies all over those icky fish.

You forgot one.
e. that leafy green vegetable that mom used to serve with potatoes and sausage. ("Geez, mom, what's that smell?" "'S'cale.")
Talk about clearing a room! That recipe produced enough gas to run my 1973 Plymouth station wagon fo a week.

[Patriot Pilot]

HISTORY major, you anal carbuncle. :mad: I just took English for fun. :cool:
In the words of brother Bluto " Seven years of college down the drain"

[John Brohm]

It's a BT-70 kit.

Bill;

I believe it's actually an ST-20 (2.04") kit. So's the later Mercury Redstone (#1921), although Estes has the diameter listed incorrectly (1.6") on the package of the re-release #2167.

John

[Royatl]

Bill;

I believe it's actually an ST-20 (2.04") kit. So's the later Mercury Redstone (#1921), although Estes has the diameter listed incorrectly (1.6") on the package of the re-release #2167.

John

Yes, the original Estes Merc Redstone was BT-60, but all the later ones (and the Jupiter C)were based on the old Centuri Merc Redstone, which was ST-20. I always wondered about that misprint on the re-release package.