Pershing II

[foose4string]

Here's a scratch Pershing II. Fudged dimensions here and there to go with available tubes and cone. I did a BT55 based version a while back but it was begging to be upscaled, so I did a BT60 this time. Rocsim says it likes a C6. A BT80 version still to come using a balsa transition and cone by Sandman....been putting that off.





View attachment BT60 PII.rkt

 

[troj]

Nice job, and I see you ran into the same problems we did -- finding actual dimensions on that beast is very difficult!

We did one, a little bit larger. Build info is here, if you're interested.

-Kevin

 

[Pem Tech]

Amazing as usual Foose, Have you ever considered giving classes on detail work? Man, I would torch a bus full of Bulgarian meter-maids to have some of your skill.

 

[foose4string]

Nice job, and I see you ran into the same problems we did -- finding actual dimensions on that beast is very difficult!

We did one, a little bit larger. Build info is here, if you're interested.

-Kevin

Thanks Kevin. I have a bunch of photos that I took and The Smithsonian and some good ones taken by another forum member at the Air Museum in Hampton, VA. There are ok drawings in the tech manual, but the written dimensions are scant. Basic length and width is what you get and the rest need to be proportioned accordingly. I think the dimensions could be extrapolated from some of those manual drawings, which is what I tried to do. Note, I said tried.... clearly beyond my pay scale at this point. A slide rule and a better recollection of my high school drafting course(or Trig) is needed.

Nice job on yours as well. That thing is really moving considering how heavy it looks. Cool video. Too bad about the ending part.


Thanks Layne. This one is far from perfect. I ignored the recoat instruction when I applied the matte clear and paid the price. Couple little alligator spots, but nothing to cry over. The PII I saw in person was a little rough looking. Not smooth at all. I'll chalk it up to scale detail..... yeah that's it.
Looks ok from a few feet away. I made the explosion hatch on this one too big. I can thank Sandman for drawing up the hatch detail, although sizing them wrongly was entirely my fault. I may leave them off for the BT80 as I don't think they were on the test round(s?) with the orange and yellow stripes.

 

[troj]

I think the dimensions could be extrapolated from some of those manual drawings, which is what I tried to do. Note, I said tried.... clearly beyond my pay scale at this point. A slide rule and a better recollection of my high school drafting course(or Trig) is needed.

That's exactly what I end up doing. Had to do the same thing on the Delta III we built, too. The nice thing on the D3 is that I later found some of the measurements I'd derived, and they were accurate, so it confirmed the approach.

It's time-consuming, but not impossible. I end up with spreadsheets with all the significant data points, and then I scale from there.

Nice job on yours as well. That thing is really moving considering how heavy it looks. Cool video. Too bad about the ending part.

Thanks, and yeah, it didn't hesitate at all about moving out. It weighed 425lbs on the pad, and we were all totally floored by how quickly it got moving.

We'd hoped and worked for a much better result, but unfortunately, we cannot control everything.

-Kevin

 

[BB-ROCK]

excellent work you have there. pershing II is one my favorite rocket next to bomarc.

 

[timorley]

Terrific Pershing II! I remember your excellent BT-55 version on the old TRF.

I had these posted in a thread on the old TRF, maybe yours, so thought I should re-post them again for everyone. These measurements are from the bottom up and end with the measurements for the complete missile.

First Stage
Length = 144.74 Inches
Max Diameter = 40 Inches

Second Stage
Length = 97.3 Inches
Max Diameter = 40 Inches

Guidance and Control/Adapter Section
Length = 61.51 Inches
Max Diameter = 40 Inches
Min Diameter = 27.75 Inches

Warhead Section
Length = 64.25 Inches
Max Diameter = 27.7 Inches
Min Diameter = 20 Inches

Radar Section
Length = 49.75 Inches
Max Diameter = 20 Inches
Min Diameter = 0 Inches

Complete Missile
Length = 417.55 Inches
Max Diameter = 40 Inches
Min Diameter = 0 Inches

Unfortunately the measurement I have combine the Guidance and Control (small upper fins mount to this) measurements with the Adapter (first reduction in body diameter. But still a big help.

I did take a best guess at splitting the Guidance and Control/Adapter measurements from photos of the real hardware by counting pixels for known measurements. Here's my best guess I used for my BT-80 build.

Adapter Section
Length = 17.51 Inches
Max Diameter = 40 Inches
Min Diameter = 33.1 Inches

Guidance and Control
Length = 44 Inches
Max Diameter = 33.1 Inches
Min Diameter = 27.75 Inches

BT-80 and 24mm is a good size.

 

[snaquin]

Looks great and nice attention to detail for a scratch built! BT-80 version sounds interesting too .....



.

 

[foose4string]

Thanks Tim. Those measurement will come in handy. I need to go back and compare those measurements to what I used on the rocksim. Didn't you draw the fins w/ dimensions also? I know somone did, but wasn't sure who. I saved that from TRF 1.0, but didn't save numbers you just listed. This will help a bunch.

 

[timorley]

Thanks Tim. Those measurement will come in handy. I need to go back and compare those measurements to what I used on the rocksim. Didn't you draw the fins w/ dimensions also? I know somone did, but wasn't sure who. I saved that from TRF 1.0, but didn't save numbers you just listed. This will help a bunch.

Yep, that was me, here they are in an attached image. Some of the pictures you posted of the real hardware were a big help to me. Again these were a guess from photos and a reference number for the total fin span being 81 inches, but close enough for me. I think the small fins might be a little on the small side. Here's also an unpainted and a launch pics of mine.

 

[foose4string]

Thanks BB-rock. Thanks Steve.

I superimposed that fin drawing over a fin profile picture I took at the Smithsonian. It's a good match. If you account for the height at which I took the pic, I'd say that drawing is right one the money.

I included another pic of the nose which I took the same day. Might be pretty helpful for someone wanting a custom. My BT80 cone is a little off, but I think it was the first one Sandman made, and we didn't have as much to go on. With this pic and the one from the tech manual, it should be much easier to get a true to scale cone. I'm wondering if he's used some of this info on some of the newer cones.

For the BT55 and BT60, I figured stock cones would suffice. Not a great match, but cheap. I used a PNC-20Y for the BT55, and BNC-50Y from Semroc for this one.