SA-2 SAM Transition

[sandman]

This was my latest custom commisions.

A =scale= SAM transition.

I'm quite pleased with the way this turned out.

The unit was made in multiple turnings later attach while still on the lathe.

There is a 3/4" ply section at the top of the bottom shoulder that has the central 1" wood dowel (for strength) going about half way through the ply and extending about 4" into the upper section.

The four corner uprights are tulip poplar and are moticed into the 3/4 ply shoulder section for even more strength.

The sections come apart for easier finishing and the customer must glue them together later.

In the combo pic mine is the one on the bottom.

It's not perfect but it's close.

View attachment Balsa transition.JPG

View attachment transition parts.JPG

 

[DaveCombs]

Hey Gordon - Where did you take/get that picture? The Air Force Museum has an SA-2 in their collection, if you need a reference.

That's really great work!

 

[sandman]

Hey Gordon - Where did you take/get that picture? The Air Force Museum has an SA-2 in their collection, if you need a reference.

That's really great work!

Thanks.

I just did a web search using Yahoo search and typed in SA-2 SAM Missile.

I think those pics were taken there. I'm didn't build this for me. It's for somebody else.

 

[Stymye]

Gordon, thats a work of art.
you could almost stain it and put it on the coffee table !
should make for an impressive rocket

 

[sandman]

Gordon, thats a work of art.
you could almost stain it and put it on the coffee table !
should make for an impressive rocket

Thanks, it was a lot of motice and tenon joinery and a lot of fiddling and fitting, turn a part on the lathe, glue another section on, turn it to match the first...take it to the drill press...back to the lathe, to get it right.

But the top and bottom just sorta "SNAP" together.

I love it when a plan works.

 

[DaveCombs]

Some time, I'm going to get with you about that SA-3 I've been dreaming about building for, I don't know, 25 years or so...

 

[Pem Tech]

Gordon,
Man that is a work of art....
You da' man!

On geez, now there is another rocket to put in the build que.

 

[Divna]

https://www.rocketryforum.com/showpost.php?p=493747&postcount=1
Anyone have the link to this museum? (and from what I can determine, the transition stays with the booster.)

https://www.cybermodeler.com/space/sa-2/sa-2.shtml

https://www.cmtonline.it/Sam2_E.htm

https://forum.valka.cz/viewtopic.php/t/631

https://pvo.guns.ru/other/croatia/index133.htm

https://tanksinmoscow.ru/Lenino/Foto/S-75_02a.htm

https://svsm.org/gallery/S-75-Dvina-Family

https://walkarounds.airforce.ru/artillery/rus/sm-90/index.htm

https://walkarounds.airforce.ru/artillery/rus/s-75/index.htm

 

[adrian]

https://www.rocketryforum.com/showpost.php?p=493747&postcount=1
Anyone have the link to this museum? (and from what I can determine, the transition stays with the booster.)

The museum itself has no website that I can find. Here's a link from the tourist website of the general area:
https://www.unteres-odertal.de/modules.php?name=Content&pa=showpage&pid=46&page=25

As for the transition, too late! In the absence of any physical evidence to the contrary, and in view of the Russian instruction poster, I put the transition cone onto the sustainer. At least that way it depicts accurately what I saw in the museum; the missile in question did have the cone but did not have a booster.

The model has now been in action. The sustainer by itself went up on a C6-3 and weathercocked badly, but there's lots of soft grass and soft ground where we launch so it survived, and that flight at least proved what I wanted proved, namely that the sustainer is stable. So then I loaded it up with a C6-5 and added the booster with a D12-0. Straight up to an apogee deployment, then a hike to recover the sustainer.

 

[Divna]

The museum itself has no website that I can find. Here's a link from the tourist website of the general area:
As for the transition, too late! In the absence of any physical evidence to the contrary, and in view of the Russian instruction poster, I put the transition cone onto the sustainer. At least that way it depicts accurately what I saw in the museum; the missile in question did have the cone but did not have a booster.

Thank you for the additional information. I have seen other photos of that SA-2.

Let me address why I believe it remains with the booster.

This photo shows the transition. On the sustainer is an electronics coupler. I have seen other photos where that is disconnected. If you look at the booster side, there are wires and piping which do not appear to have a disconnect.

This photo Shows 'the other side' which appears to show a more complicated connector at the sustainer side, while this photo looks to have a M/F connection onto the tank. Notice in this photo the 90d connector with a slip type fitting?

Until I found photos of released guidance fin locks, I wasn't sure about the pivot joints on the transition (seen top & bottom here). This photo shows a large hole (near red dot, not the huge hole by the red text) in line with the fin. This photo shows a guidance fin lock on the top (missing on the bottom) and the pivot. If you look at the lock, it appears to be fixed to the bracket on the transition.

Look closely at this photo. The large hole is quite a bit forward of the transition. I believe it shows the transition/booster have slid back from the sustainer. If you consider the line of small holes in this photo which appear at a reduced diameter from the sustainer, and this photo which shows the transition, an inter something and the nozzle. I believe the first photo shows an inter-shield which has been removed from the museum piece so the nozzle is visible.

So, the rocket goes to stage. The pin locks disengage allowing the transition to slide back. This releases the guidance fins while pulling the electrical connector out and those plumbing fittings. Preventing the transition from banging into and damaging the nozzle, there is an inter-shield around the nozzle.

I'm not sure why else there would be the inner shield.

But to add to the uncertainty, this photo would seem to support the 'with sustainer' position as the transition is on the sustainer at assembly. However, I believe it would have been shipped on the sustainer to protect the nozzle or that's simply the point in time of assembly prior to adding the booster motor.

 

[adrian]

Thank you for the additional information. I have seen other photos of that SA-2.

The older SA-2B with East German markings? (Easier to model as, unlike later versions, it has no external fuel and oxidant lines on the sustainer.)

This photo shows the transition. On the sustainer is an electronics coupler. I have seen other photos where that is disconnected. If you look at the booster side, there are wires and piping which do not appear to have a disconnect.

The lower pipe does not appear to have a disconnect at either end!

This photo Shows 'the other side' which appears to show a more complicated connector at the sustainer side, while this photo looks to have a M/F connection onto the tank. Notice in this photo the 90d connector with a slip type fitting?

Also, that photo seems to show a solid plate at the base of the transition.

It does also appear that the latches act to lock both the steering fins and the transition itself, then release them at separation.

If you consider the line of small holes in this photo which appear at a reduced diameter from the sustainer, and this photo which shows the transition, an inter something and the nozzle. I believe the first photo shows an inter-shield which has been removed from the museum piece so the nozzle is visible.

No, I don't think that's a separate shield. Partly because in this photo the "shield" and main transition seem to come together at the forward end, and partly because there would then need to be some additional clamp mechanism to release the "shield", which itself would then have the danger of banging into the exposed nozzle.

But to add to the uncertainty, this photo would seem to support the 'with sustainer' position as the transition is on the sustainer at assembly. However, I believe it would have been shipped on the sustainer to protect the nozzle or that's simply the point in time of assembly prior to adding the booster motor.

I agree that the transition is shipped attached to the sustainer; the poster appears to prove that.

So my model with the transition attached to the sustainer may not be completely accurate during flight. However, it does depict what I saw in the museum (sustainer plus transition, without booster), which was the main object of the exercise - a sort of late "souvenir". It also allows the booster to be attached for a two-stage flight, and once the rocket is a few hundred feet up, good luck trying to spot the transition cone. :lol:

Here are a couple more reference sites; it helps to be able to read German when looking at the second.
https://svsm.org/gallery/sa-2
https://www.peters-ada.de/sa2.htm

 

[Divna]

I meant I've seen shots of that SA-2 from a different angle. Unless there are 2 museums with those yellow carts and the same 2 missiles together. I just noticed the booster is against the back wall.

This photo and this photo show the booster separating from the sustainer. Closes-ups in this photo and this photo.

In the closeups you can see the shield and it's screw heads corresponding to the holes in this photo where the shield has been removed to view the nozzle. I do not believe they seperate that inner shield (hence the screws).

The closeups did have me confused over the apparent O-ring until I realized it was just roundbar looped over the missile and welded to the transporter.