Found! Obi-Wan Kenobi ANH Lightsaber Emitter

[Prop Runner]

Originally posted by Barry@Oct 10 2005, 02:51 PM
This thread just keeps getting better and better.

Thanks to all you guys who are playing Ace Detective, especially Chris.

gabe, your drawings look great, I can't wait for a final accurate blueprint of this piece.

I know many of you want an exact copy of the piece, as do I, but someone needs to be thinking about making a version that will fit onto available Obi sabers. A bunch of glue and filler, while probably accurate in the extreme, will look pretty messy on a collector's piece. N'est pas?

B

[snapback]1093488[/snapback]​

Thanks for the kind words, Barry - means a lot coming from you.

As for attaching a replica or an original to an existing grenade stem, I propose 2 attachment methods:

1. adapter ring

2. cheat on the replica

Here's how my Darth Hez saber looks at the attachment area - he basically made it a solid interior with a counterbored hole:

That would be option 2.

Option 1 would involve replicating all the original parts and epoxying an aluminum or delrin adapter ring between the brass retainer on the end of the grenade stem and the inside wall of the inner pipe:

(above 2 photos: Chris Trevas, POSW)

Here's the retainer on the far left laying next to a similar grenade stem:

Laying the parts in the order they assemble, we get:

And now we put them together:

and depending on how tall one makes the adapter ring, the front should look like this:

Of course, since we never have any clear view of the front-interior of the screen-used emitter, this area could be left open to fantasy interpretation, i.e., a closed-off adapter ring that conceals the brass retainer and has a smaller concentric set of lips and radial holes like many fan-made sabers I've seen, including my DH saber.

If anybody's curious, I modeled the grenade, vane & stem based on my DH saber. The brass retainer is an eyeball job based on the proportions in the above photos. To get the ID of the adapter ring right, I'd need the true diameters and height of the retainer (anyone got one?) For those who simply want to swap out their inaccurate emitter for the new accurate replica, the adapter ring ID and height would depend entirely on what you've got going on at the attachment point with the emitter.

Guess having come this far, should I go ahead and model the clamp, capacitors, bubble strip, gear, and handwheel? Show of hands?

- Gabe

 

[Serafino]

Gabe, what you are calling the 'retainer' is not in the emitter. For detailed discussion of what's in there see this thread:

http://www.therpf.com/index.php?...opic=74377&st=0

Of particular interest are these pics:

http://img9.exs.cx/img9/7523/FL-Reflector.jpg

http://img39.exs.cx/img39/5748/Reflv4.jpg (not IMO fully accurate, but interesting)

and these posts:

http://www.therpf.com/index.php?...ndpost&p=871909

http://www.therpf.com/index.php?...ndpost&p=873787

http://www.therpf.com/index.php?...ndpost&p=896143

 

[franz bolo]

I don't think you saw it, but I raised my hand just a second ago.

FB

 

[Serafino]

Yeah it would be great to have a set of drawings reflecting ACCURATE state-of-the-art Obi dimensions. Then maybe the next round of parts will be truly accurate.

Arguing about all of that is a whole separate thread though.

 

[Prop Runner]

Oops - forgot to mention that I tweaked the dimensions on my model so it's now correct to Chris' dimensions of the first balance pipe. Here's a new comparison with the correct balance pipe:

You'll notice that the outer pipe flange diameter is smaller than my previous rev, and that itook out those 8 side holes in the inner pipe. I also increased the angle of the bevel chamfer from 23 degrees to 30 degrees, which one would expect, since 60-30 chamfer bits are standard tooling. I invite the most nitpicky amongst us to point out any issues they have with the design or proportions - again, because I want to get this right.

- Gabe

 

[Prop Runner]

Originally posted by Serafino@Oct 10 2005, 10:22 PM
Gabe, what you are calling the 'retainer' is not in the emitter.  For detailed

Thanks for reminding me, Andres. I'm then at a loss as to why Chris includes the retainer in the "bill of materials" for the saber in POSW. Is it possible there's a black bolt coming out of the vane stem where the retainer would be, and that's what accounts for what you and others see as aa dark "depression" in your photo anaylsis in your emitter thread?

I ask, because the vane stem ends just past the rear of the emitter - there must be something else holding the stem to the inside wall of the balance pipe. If it's not the retainer, what is it?

Let's try and figure this area out once and for all.

- Gabe

 

[Sporak]

Here's how I put mine together using the Romans Emitter...I wanted to use the grenade connector piece (spare brass part) since I had one...but still wanted the depth that we see...so I cut a replica part down and used it...

I shined mine up, but it could easily have been weathered down dark...

So this brings to mind that there might yet be a missing part that is unseen, but existed on the original, The True Connector... Arrrrgh.

 

[Serafino]

Gabe I'm just gonna wait until the specs are posted. It strikes me as completely crazy to try scaling this thing off a new set of photos of a found part when we're about to know the dimensions taken directly FROM said found part.

But as I hinted earlier, I've been told the flange is 2.2" in diameter.

As for how the stem is attached to the emitter, it looks to me like there is an intermediate piece which fills the gap. There is something inside there down around the top of the stem. I've demonstrated that even when the emitter appears 'dark' there is a transition at the place where the 'reflector' begins in other shots.

 

[Prop Runner]

Originally posted by Serafino@Oct 10 2005, 11:14 PM
Gabe I'm just gonna wait until the specs are posted.  It strikes me as completely crazy to try scaling this thing off a new set of photos of a found part when we're about to know the dimensions taken directly FROM said found part. 

But as I hinted earlier, I've been told the flange is 2.2" in diameter. 

It's all good, Andres. I'm just working off the crumbs Chris is feeding us... From what he previously posted, we now know that the flange diameter is 53.5 mm, so I don't see that changing radically at this point, do you? 2.2" is 55.8 mm, which is also the diameter of my DH emitter, and what I used to model the previous rev (and you can tell that the flange is just too wide). Sure, there are several dimension gaps to fill, but if my model is correct, then it'll just be a matter of plugging the right numbers in. Call me crazy, but I love making the changes with each new discovery.

As for how the stem is attached to the emitter, it looks to me like there is an intermediate piece which fills the gap.  There is something inside there down around the top of the stem.  I've demonstrated that even when the emitter appears 'dark' there is a transition at the place where the 'reflector' begins in other shots.

Do you mean this comparison you posted?

Looks like you and Sporak are on a similar path, with just a minor difference of interpretation on the transition. It could simply mean that the adapter ring ILM used to attach to the vane stem had a conical cross section, and that indeed the brass retainer was not utilized, or was modified beyond recognition.

Sporak - thanks for posting your pics of the retainer - I didn't know how the top end looks. Could you perhaps shoot me the part's dimensions? I'd like to "play with it" a little...

Thanks,

Gabe

 

[Serafino]

Gabe--these two posts are more representative of what I'm talking about:

http://www.therpf.com/index.php?...ndpost&p=873787
http://www.therpf.com/index.php?...ndpost&p=896143

As to the dimensions of the flange, I may not be remembering correctly but I thought Chris has only posted the diameter of the incorrect flange.

Anyway, I am sending money in about an hour to have one of these sent to me, with any luck I will be able to answer all these question in detail within a week.

(edit: fixed links)

 

[lonepigeon]

I guess I forgot to mention earlier that the flange on the balance pipe with beveled holes is wider thatn the other as Serafino said. I thought he mentioned it because I posted it.

The flange area/top section is the only area that is different from the piece on the opposite side (all other dimensions are identical):

Quote from my source:
""""
-The ring of holes is recessed, but also dished (or reverse-bevelled?), in two stages, the first gradient sloping down from the top surface for 3mm (so halfway into each hole) and then a second gradient 3.5mm wide takes us to the edge of the inner pipe.
-There is still a join line visible at either the same or approximately the same distance from the inner aperture (the same two-part construction that foxed me on the other part)
-The main flange is 2 to 2.5mm greater in overall outer diameter, which is actually visible on the prop photo if you compare the two versions of the part and the photo.
-There is a bevel on the lower edge of the flange not present in the other part. This is 2mm wide and drops at an angle of approx 45degrees.
""""

 

[Prop Runner]

Andres - cool beans on the purchase..

Oh, and those links take me to the general RPF list of forums, not any particular posts - please fix

Chris - thanks for the correction - guess I have oto tweak the flange diameter back to what it was... But this time I'll wait until I have all the other critical dims available.

Could you please ask your museum source to take a photo of the two pipes facing one another, with the flanges mated and aligned along their centerlines? Probably best to stack them on a table and take an eye-level shot against a neutral background, what do you think?

And what's the story with the brass retainer now? :confused

Thanks.

- Gabe

 

[lonepigeon]

Originally posted by Darth Lars@Oct 10 2005, 10:15 AM
So, there are only seven emitters per engine, and not 14 as we thought earlier. That makes it harder to justify the acquisition of one.
I thought the outer diameters for step 1 and 2 would have been fractions of a millimeter below 30 and 40 mm respectively. Nice, even metric dimensions.

[snapback]1093382[/snapback]​

There are 9 "emitters" per engine plus 9 almost correct balance pipes (flat ring of holes w/ lip, slightly smaller flange) and 9 IG-88 heads.

The trick now is watching for variations.
Different balance pipes are listed in the parts catalog.

To quote my source:
"""""
I've been right through the parts catalogue, and there is only one reference to an altered interconnector assembly; Mod 585 dated 16.10.1952 which introduces combustion chamber interconnectors of increased area for the Mk.8 and 9 Derwent. Note that this does not necessarily refer directly to the balance pipes, but may have some bearing on them and some relationship to the different pipes listed in the parts cat.
"""""

The big question still is how to tell if an engine has the correct IG-88 heads without opening it up.
My source has found it's a modification documented for Derwent Mk 5, 8 and 9 engines depending on their use. Specifically it's Mod.622 8.7.1952, which is the introduction of a reduced number of holes in flame tube.
My source:
""""The problem here is that if the mod is not rendered essential by any change in engine Mark or by an official mod, then this modification need not have been implemented on a given engine. You will therefore need to eyeball the flame tubes or improve your guess odds by checking the data plate, visible external part numbers, anything that can be used to date the latter changes made to the engine in question that might make it more likely that the thing has the flame tubes you want."""""
Of all the engines I've seen on the web there's only been one that I've seen with the correct IG-88 heads and that's at the museum my source works for (the very one shown in pieces in my last couple pics).

 

[Serafino]

Random Emitter Talk

 

[kurtyboy]

So an engine with the correct IG88 head flame tubes might not necessarily have the correct emitter balance pipes?

When these mods were made, were they made to all current operational engines as a standard upgrade or only a few select ones?

Were the Derwent engines still being manufactured after 1952? In which case would any engines manufactured after this date automatically have the upgrades as standard (and therefore more probably have the correct emitters)?

 

[Serafino]

So the enlarged interconnect is a mod even on the Mk 9? Interesting.

 

[lonepigeon]

At this point we don't even know if the balance pipes are effected by this mod.
It could only change the interconnector clamping. There are multiple balance pipes listed in the Derwent parts catalogue though.

The only difference on the Mk.9 is supposed to be the ignition system.

 

[Serafino]

Well this is from a Mk 9. Measurements were approximate. Sadly it can't be measured again as unfortunately it's been put in the mail. :unsure

[image]http://www.therpf.com/archive/obi_emitter/obiemreal5dv.jpg[/image]

uh... to me, that is.

eek2 :lol :love :love :love :lol :eek

Please forgive the overacting, I am just stunned with joy.

 

[Reel Fakes]

WOOOOHOOOOO...

Good on you

I can't express how happy I am for you.

Congrats,
Chris

 

[JOHNLP (OBI-JOHN)]

:cry It's so purdee. :cry

I tell ya, my wife is so sick of me "wasting away" on this threat she's insisting I look at porn on the computer again. LOL.

j/k

That's awesome man. Glad you are getting it. :thumbsup