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marvSRG

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Hey guys out there who have ROTW and/or are scale modelers. I am a fan of the X-17 sounding rocket, and I'm considering building a 3" or 4" version complete with spin rockets, and possibly operational stages. The only thing that confuses me about this rocket is the stage 2 to stage 3 transition. The 2nd stage of the X-17 is a cluster of three motors...but they aren't in a cylindrical airframe. They're in a "rounded triangle" type form...similar to a Nike Herc booster but with 3 motors. With this, it makes the transition from stage 1 to stage 2 and then the transition from stage 2 to stage 3 a bit complicated as the 1st and 3rd stages are cylindrical. They come out to have rather unique geometries.

My main concern/wonder is the fact that the drawings in ROTW make it look like the 3rd stage is off center in comparison to the other stages. This #1 confuses me, and #2, if it is what it appears to be, then it totally screws up the physical appearance of the rocket, and I'll abandon the idea of building it. I'm hoping and guessing that the unique geometries of the rocket just make it appear this way in the drawings. Can someone explain if it really is off center, or if it isn't, and then how does the stage 2 to stage 3 transition really flow?

If ya got this far, thanks for reading my blabbin'. Can anyone help on this one?

Thanx
 

Bill

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Originally posted by marvSRG
Hey guys out there who have ROTW and/or are scale modelers. I am a fan of the X-17 sounding rocket, and I'm considering building a 3" or 4" version complete with spin rockets, and possibly operational stages. The only thing that confuses me about this rocket is the stage 2 to stage 3 transition. The 2nd stage of the X-17 is a cluster of three motors...but they aren't in a cylindrical airframe. They're in a "rounded triangle" type form...similar to a Nike Herc booster but with 3 motors. With this, it makes the transition from stage 1 to stage 2 and then the transition from stage 2 to stage 3 a bit complicated as the 1st and 3rd stages are cylindrical. They come out to have rather unique geometries.

My main concern/wonder is the fact that the drawings in ROTW make it look like the 3rd stage is off center in comparison to the other stages. This #1 confuses me, and #2, if it is what it appears to be, then it totally screws up the physical appearance of the rocket, and I'll abandon the idea of building it. I'm hoping and guessing that the unique geometries of the rocket just make it appear this way in the drawings. Can someone explain if it really is off center, or if it isn't, and then how does the stage 2 to stage 3 transition really flow?

If ya got this far, thanks for reading my blabbin'. Can anyone help on this one?

Thanx
As far as I can tell, the 3rd stage is centered; it just does not make any sense any other way. The transition is oddly shaped and looks funny except from several specific angles.

Developing the surface for the transition should be fun...it is a combination of three triangles interleaved with three partial cones.

It will be way cool to use MicroMaxx motors in the spin rockets...


Bill
 

powderburner

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marv,

I am not very familiar with the X-17, but looking at the photos that I could google quickly, I think the answer to your question might be simple.

Think in terms of a end-view of the vehicle stack, keeping in mind that the second stage (the ‘off-center’ one) is made up of three motors bundled together.

When you center that second stage in the stack (see my cheesy drawing, attached) and view it from the side, then one side of the second stage will stick out farther from the overall vehicle centerline. Note the difference between ‘a’ and ‘b’ on my drawing.

If this is true, then any photos of the X-17 taken from the sides will make the second stage look off-center, and any photos taken from the front or rear will make the second stage look properly centered again.

What do you think?

BTW, I sure hope you are not going to try for ‘scale points’ for the actual flight of your model. The real X-17 flew to maximum altitude on first-stage power, then nosed over and accelerated downward using the second and third stages to get to Mach 14 speeds. Please let us know when and where you will be launching?
 

Peter Alway

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Powderburner is exactly right. The cluster of three motors in the second stage is exactly centered, but looks off-center unless you view it from the right direction (well, one of six right directions).
 

marvSRG

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Thanks to all...and no, I'm not planning on a scale flight pattern, although some of the later launches ( I believe some ship launches) used all of the stages for altitude. If I did three stages, though, I'd do them "going up".

I appreciate it guys.
 

Silverleaf

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...Getting answers from the author of Rocket's of the World directly.....

Priceless !
 

Peter Alway

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Originally posted by Silverleaf
...Getting answers from the author of Rocket's of the World directly.....

Priceless !
Naw. $35 plus shipping.
 

Silverleaf

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Lol..well even at 35 bucks, thats a steal.

I'm going to have to get the supplements from you Peter, bout time I complete my collection. Are you planning to add another supplement to this growing fleet of books ?.

If so, I better get ordering the older ones first. Don't want to fall too far behind. 8)

Cheers my friend,
 

Peter Alway

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Originally posted by Silverleaf

I'm going to have to get the supplements from you Peter, bout time I complete my collection. Are you planning to add another supplement to this growing fleet of books ?.
I am plugging away on the 2004 supplement. I've drawn the Athena H, Skua, Swiss-German Zenit, Aerobee 100, and, uh, well I should get offline and back to work.
 

powderburner

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Peter,

Are there any plans to ever collect together all the supplement data and publish a volume II of ROTW?
 

marvSRG

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Are there any plans to ever collect together all the supplement data and publish a volume II of ROTW?
Yeah, that would be nice or at least a book with all the supplements in it...not quite a Volume II of ROTW, but all the supplements in one book. I'd get that.
 

Peter Alway

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Originally posted by powderburner
Peter,

Are there any plans to ever collect together all the supplement data and publish a volume II of ROTW?
I don't see anything like this in the foreseable future. I'll be plodding along pretty much the same way unless something dramatic happens.

I will tell you that in a perfect world, if I actually found a day job that I could stand and that I could live on, I would dump (allow to sell out and not restock, *not* throw out!) every product but <i>Rockets of the World</i> (Bill at BMS could continue the kits, because that requires no work on my part). When <i>Rockets of the World</i> would sell out out, I'd throw all my other scale data into that pot, expand it to 600+ pages, raise the price to $60, and sell that book alone.

But as I said, I don't see this happening soon.
 

powderburner

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Allrighty then, would you consider a small discount on price for a combination of one copy of all the supplements, sold together as a package?
 

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