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For discussions on tanks, artillery, jeeps, etc.
1:1 scale Flak 103/38 3cm Jaboschreck
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
Armorama: 553 posts
Posted: Friday, January 24, 2014 - 05:25 PM UTC
Here it is, the sole existing Flak 103/38. We're about halfway done with the restoration right now. We've made huge progress on it over the past two weeks and mechanically it is fully functional. There's still a considerable amount of surface rust to remove and we'll be repairing the sight mount over the next couple weeks.

There are MANY differences between this and the Dragon kit, which I believe was based on the prototype. I've been working on making my kit more accurate while working on the real thing and there really are a lot of differences.



















Petro
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Connecticut, United States
Joined: November 02, 2003
KitMaker: 943 posts
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Posted: Friday, January 24, 2014 - 06:24 PM UTC
You get to play with the coolest toys.
AFVFan
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North Carolina, United States
Joined: May 17, 2012
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Posted: Saturday, January 25, 2014 - 03:37 AM UTC
Neat! I love the precision cut opening in the end of the muzzle brake!
marcb
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Overijssel, Netherlands
Joined: March 25, 2006
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Posted: Saturday, January 25, 2014 - 05:39 AM UTC
Must be a challenge to restore if you have the only one. Would you be willing to post the differences between the real one and the Dragon kit?
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
Armorama: 553 posts
Posted: Saturday, January 25, 2014 - 12:29 PM UTC

Quoted Text

Must be a challenge to restore if you have the only one. Would you be willing to post the differences between the real one and the Dragon kit?



Fortunately the gun has been stored inside for years and is in superb condition. The mount and trailer are in surprisingly good shape for having been outside at Aberdeen for years. We disassembled everything, cleaned it, lubed where necessary and put it back together.

I have shot over 300 photos so far and have already asked Dragon if they are interested in accurizing the kit. The biggest two omissions on the kit are the two equilibrators and the charging handle. The actual gun cradle is incorrect and the mount needs to be open on the bottom so the expended brass can fall to the ground out of the bottom of the gun (like a .50 cal).
More later!
Tiger_213
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California, United States
Joined: August 10, 2012
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Posted: Saturday, January 25, 2014 - 12:57 PM UTC
Glad you guys have made some progress Jon. It's an interestingly, un-German style muzzle brake; I didn't notice that on your intial post concerning the 103.
HermannB
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Bayern, Germany
Joined: October 14, 2008
KitMaker: 3,881 posts
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Posted: Saturday, January 25, 2014 - 08:07 PM UTC
What that red-painted model plane in the background? Did you get the fitting target drone for the Jaboschreck?
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
Armorama: 553 posts
Posted: Sunday, January 26, 2014 - 02:58 AM UTC
The airplane in the background is a WWII OQ-2A target drone used for training by US AAA gunners. The fuselage is in pretty good shape, but the fabric on the wings is shot. I'm going to attempt to restore it using a few proven conservation methods, but we'll see...
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
Armorama: 553 posts
Posted: Sunday, January 26, 2014 - 04:56 AM UTC

Quoted Text

Glad you guys have made some progress Jon. It's an interestingly, un-German style muzzle brake; I didn't notice that on your intial post concerning the 103.



I've noticed a number of things on this piece that are very rough and indicative of late-war construction. My hunch is, at least some of the components were made by slave labor.

The quality of the welds in a few different places were so poor that there was almost zero penetration. The locking handle on the traverse mechanism was a prime example of this. The welds were literally held on by 1-2mm of metal and snapped cleanly when we tried to loosen it. Fortunately it cleaned up easily and re-welded perfectly.

If you look at the seat mount (photo above), it is very different from the regular, stamped and welded Flak 38 seat mount. This is just a piece of 2" steel pipe with the proper fittings welded to it. The welds on the seat were pretty poor too.





panamadan
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Minnesota, United States
Joined: July 20, 2004
KitMaker: 1,342 posts
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Posted: Sunday, January 26, 2014 - 05:20 AM UTC
I hope that Dragon takes you up on your offer. Are there pics comparing the problem with the kit and actual gun?
Thanks, Dan
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
Armorama: 553 posts
Posted: Sunday, January 26, 2014 - 05:46 AM UTC
Here's my model.
Left side, the most noticeable change is the charging handle at the back of the vertical portions of the gun mount. It is simply a hand crank with a pulley on the end. The charging chain from the gun slides in and secures with a T-handle. Charging the gun is done by rotating the handle clockwise.




Rear of the gun and mount. You can see the charging handle better from this angle. The traverse mechanism is more streamlined than the standard Flak 38 to allow clearance for the two equilibrator tubes that extend out underneath. Those tubes extend all the way to the front of the mount. Each has two one-meter long springs in it and are attached to the gun mount via cables. The spring tension counteracts the weight of the gun and balances it for smooth elevation.

Above the traverse mechanism is a piece of sheet steel welded to both sides of the mount.




Right side: The elevation mechanism is completely different from the Flak 38 as well. It's much simpler and I pretty much just cut a piece of thick sheet styrene, laminated it with a thinner piece to get the correct seam on it and cut and sanded to shape. Both traverse and elevation handwheels were grabbed from my Commander Models 90mm M1 AA gun (there were two extras!) and look correct for the late-war spider wheels found on this particular gun.

The sights are correct, however the mounting arm is not. Our sight arm was damaged, so we're in the midst of straightening it, but it is basically a stamped sheet metal arm that is different from any of the options included in the kit. Once we get it straightened, I will post pics. I took the kit sight arm and used the 90-degree angle arm from it, which is correct. It's the support arm that needs to be significantly modified.





Top view: Not much else to say about this



Front view: biggest thing here is the pulleys for the equilibrator tubes. The cable comes out of each tube, comes around the pulley on the front of the mount here and then connects to the angle iron that is the actual gun mount. I have to remove the gun from mine, as the gun mounting system included here (standard Flak 38) is not correct. The gun literally mounts on two 2" wide pieces of angle iron and pins in place.

Also, the front of the gun mount platform has 4 grab handles on it. Cut the two outer (smaller) handles off. That's a Flak 38 feature.



Trailer: The only modification needed for the trailer is the removal of the fenders and the mounting of the toolbox. Two brackets mount it directly to the chassis on the right side. The kit toolbox needs to be filled on the back side (and you can see I haven't quite finished that yet!) and you're good to go.

When we start the restoration of our 1942 Flak 38, I will do a number of side-by-side comparison photos. That'll be later this year!
Tiger_213
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California, United States
Joined: August 10, 2012
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Posted: Sunday, January 26, 2014 - 06:13 AM UTC
Lower quality welding materials, a lack of welding training, accelerated production schedules and I think we all nowhere were plenty of instances where slave workers literally risked their lives to sabotage equipment during production. At least the weak welds make it easier for you to remove parts. That's probably a pretty welcome circumstance in restoration.
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
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Posted: Monday, January 27, 2014 - 06:32 AM UTC
It's been fascinating so far. Of course, bringing this piece back to operational condition has been awesome, but at the same time it has been sobering, especially since I'm Jewish. Then again, who better to restore it?

We're going to straighten and repair the sight mount next week and should have the sighting mechanism up and running shortly thereafter.


Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
Armorama: 553 posts
Posted: Monday, February 03, 2014 - 03:48 PM UTC
Well, we've been focused on the sighting system this past week and we're making headway. The connector arms are all in place, the pivot points are lubricated and moving freely.

Today we pulled the mounting arm off of the mount base so we could repair it. This was pretty fascinating, since there is an electrical conduit that runs up through it to power the illuminated sight. I'm still not 100% clear on how it works, but we'll figure it out.

We were able to straighten the mounting arm about 80% before the metal started to split. Time to pass it off to the professionals at the welding shop and let them have a go at it! They were going to weld the split metal back together anyhow, so straightening it a bit won't add too much.

While disassembling a few different pieces today, we uncovered some very nice examples of original paint. The trailer was originally painted Schwarzgrau and it looks like it was just overpainted Dunkelgelb when it was converted to a Jaboschreck trailer.

Dunkelgelb


red primer


Inside the sight mount was a beautiful red primer, and I'm talking REALLY red. And of course dismantling the tail light, unveiled a pristine example of Dunkelgelb.

Sight mount and ring sights


As you can see, it got pretty mangled at some point.


We straightened it out pretty well today, but it still needs repairs. Should get it back by Thursday or so



The sight mount box. the ring sights mount to the right on the lower mount and the optic sight mounts on top of the box.

Tiger_213
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California, United States
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Posted: Monday, February 03, 2014 - 03:56 PM UTC
Some really nice color indeed. Where was the 103 even at before you guys got a hold of it?
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
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Posted: Monday, February 03, 2014 - 03:59 PM UTC

Quoted Text

Some really nice color indeed. Where was the 103 even at before you guys got a hold of it?



The gun was taken off of its mount in 1990 and transferred from Aberdeen to the National Air & Space Museum. The mount remained at Aberdeen until late 2012 and the gun arrived here at Ft. Sill at the end of December.
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
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Posted: Tuesday, February 04, 2014 - 10:36 AM UTC
Been focusing on the sight mounts today. We've got the ring sight/direct fire sight and the optic sight mounted parallel once more! Banging out the dent in the mount box was a royal pain, but it has paid off. Now we're trying to pull the range adjustment knob so we can straighten it and get that working again.

We also got a number of additional parts blasted today and prepped for paint.

Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
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Posted: Tuesday, February 11, 2014 - 11:22 AM UTC
The sight arm is repaired! We reinstalled the sighting mechanism today and mechanically the Jaboschreck is complete and fully functional. Now we need to clean it and repaint it. We've already ordered accurate colors from TM9 and it will be painted exactly as it was at Aberdeen in November 1946. It still wore its original WWII camouflage scheme then and we have the photos to support the paint scheme.









DerGeist
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Ohio, United States
Joined: January 21, 2008
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Posted: Tuesday, February 11, 2014 - 11:50 AM UTC
Absolutely fascinating thread. Is it known where the gun was captured?


Erik
Tiger_213
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California, United States
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Posted: Tuesday, February 11, 2014 - 11:52 AM UTC
It looks fantastic Jon, very 'late war German' I think. I'm assuming the two holes in the seat are for bolt that would hold a cushion?

I find it odd that it has a shaped foot rest, I don't remember seeing anything like that on other German AA.

Looking forward to seeing it after its date with the paint booth.
Petro
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Connecticut, United States
Joined: November 02, 2003
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Posted: Tuesday, February 11, 2014 - 01:33 PM UTC
This is a great thread, Jon. Thanks for posting this.
I can't wait to see it painted.
I hope you can also post the APG photo.
Cobrahistorian
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Oklahoma, United States
Joined: November 11, 2006
KitMaker: 710 posts
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Posted: Wednesday, February 12, 2014 - 01:29 AM UTC
I'll see about posting one of the Aberdeen 1946 pics once I get to work today.

Not sure exactly when it was captured. The details in the property jacket are minimal. My hunch is, it isn't one of the 17th Panzer Division guns, but considering there were roughly 150 of them actually produced (3000 contracted between Rheinmetall-Borsig and Suhl, ours is a Suhl gun)and twenty went to the 17th Pz Div's Panzergrenadier Regiment 40 and Flak Abteilung 297, I suppose it is possible.

Paint scheme was overall Dunkelgelb with very light green and brown overspray. The 1946-dated photo I have has large splotches of what I am interpreting as Rotbrun, but those may have been added once it got back to the US. Trying to figure that out now.

Jon


MLD
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Vermont, United States
Joined: July 21, 2002
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Posted: Wednesday, April 09, 2014 - 12:02 AM UTC
Jon,
Thanks for posting these images. They are a huge help with the DML gun.
My first one was already 80% built before this thread came across the screen. So some of your modifications are possible, and some are not.. oh well, next time.

DML has a part protruding upwards (a23?? I dont have the instructions here at work) from the gunners left that is not long enough to reach the sight platform that crosses between the vertical sides. This part looks to be a mechanical linkage left over from the other flak guns this kit shares parts with.
I can scan the instructions later if this makes no sense.

Your photos show the wheel to the gunners left, but not the linkage. Probably one of many little glitches in the DML instructions, they are kind of famous for that.


Thank you very much for documenting this little known, but wicked looking little gun.

Mike
Cobrahistorian
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Oklahoma, United States
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Posted: Friday, July 25, 2014 - 06:06 AM UTC
Hey all!

I'm sorry I haven't added to this one for a while, but things have been extremely busy around here. Fortunately, we have been able to work on the Jaboschreck a bit and today we re-mounted the gun. She's about 90% finished now, but there are a lot of little details yet to do, plus we have to build the magazine for it from sheet metal.

We stripped it down to its individual components, cleaned them, greased them (where needed) and reassembled them. The only fabricated parts on it are the mounting bolts for the gun, since the originals are long gone. Everything else, including the tires and tubes (valve stems replaced)are original to Flak 103/38 Nr.175. 175 came out of the Suhl plant, which was contracted to build 1000 of the guns, while Rheinmetall-Borsig was to build 2000. It is uncertain how many were produced, but we do know that 40 guns did get to the 17th Panzer Division in February 1945 and were evenly split between Panzergrenadier Regiment 40 and the Heer Flakabteilung 297.







Tiger_213
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California, United States
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Posted: Friday, July 25, 2014 - 07:13 AM UTC
Looks awesome, Jon.