The Millennium Falcon's boarding ramp: solving a mystery

I’ve been working for a while now on a motorized boarding ramp for my 1:144 and 1:72 Bandai Millennium Falcons - a surprisingly tricky exercise. Partly because the ramp design wasn’t engineered for operation from the start - the original Star Wars set had static decorative hydraulics.

Put simply, as the ramp pivots down, basic geometry means that the “hydraulic pistons” will have to move laterally. That, or they tilt or move, or the ramp changes length. I’ve managed to get working designs, but they never looked quite like they do in Empire, which is the first time we see the ramp moving.

Anyway. The other day I came up with a simple idea which I think replicates the Empire look, combining a pivoting ramp with lateral post motion. I’ve discussed the idea with the amazing Stinson Lenz, and he built a 3D model which shows the theory is workable.

Maybe this is already a known solution, but it seemed new enough to me. So I’ve added a page to my Falcon info site, describing details of the ramp. Hope this is useful to someone!


- nkg

Thanks for sharing this , interesting information . Plus one can’t have too many pictures for reference of this beautiful ship .

One quick question though , and I’m not trying to be smart - but how did Deagostini get their ramp mechanism to work ( vertically only ) on their Model ?
I mean , apart from where/ how it’s attached to the ramp ( wish it were different ) , it seems to travel well , ala the films .

:cheersGed

Wow! Deja vu! Over a decade ago, I designed a couple of methods for the ramp moving mechanism that allowed the ramp to have a fixed hinge and the vertical “posts” to remain vertical and non-sliding laterally. The trick is in the joints where theses “posts” attach to the ramp itself. In my designs, these joints are not simple pivots.

One design uses an eccentric fixed to the ramp, especially the bottom most docking arm “chunks”. Those eccentrics are inside those “chunks”, and the “posts” feature a ring on their bottom ends encircling the eccentrics. When the “posts” are lifted, the eccentrics, being fixed to the ramp, rotate with the ramp. As luck would have it, the “chunks” are slotted inboard to outboard where the “posts” disappear into them. So, in effect, the ramps natural lateral component of motion is “bounded” by the slots, which I determined was sufficient for the motion involved. Fortunately, where the upper posts join the ramp, there is even less of a lateral component to the ramp motion so as to be reasonably unnoticeable. The eccentrics inside the “chunks” were rather elaborate, but the ones for the upper “posts” were simple. I didn’t think the set designers would necessarily have used such a design.

However, I determined an even simpler design where instead of an eccentric, there is a slot, and the bottom ends of the “posts” have rolling bearings attached to them that roll laterally in the slots. Again, where the upper “posts” join the ramp, this motion is smaller.

I do not know what was actually done for the TESB set, but I think my designs are certainly reasonable solutions.

Mark

gedmac66 said:

One quick question though , and I’m not trying to be smart - but how did Deagostini get their ramp mechanism to work ( vertically only ) on their Model ?
I mean , apart from where/ how it’s attached to the ramp ( wish it were different ) , it seems to travel well , ala the films .

Click to expand...

Yes, I've thought about the DeAgo design. I have one here, but it's dismantled and in a box, and I wasn't the one who assembled it (I bought a partly assembled DeAgo Falcon). But from what I recall when I looked at it, the DeAgo model basically works because it has a lot of slop in the design. The top of the metal wires, through which the decorative plastic parts of the "piston" move, feed through sort of oval shaped slots. This lets the post parts move around a lot.

The other thing is that the ramp isn't motorized via the posts. Instead it uses a rather ugly and visible motor assembly which fastens to the upper end of the ramp. That part does the actual lifting, and the posts are mostly decorative, and restrict the side motion a little bit.

That's my understanding of the approach they used - anyone else care to go into more detail at all?

- nkg

I'm not sure how they got the live action set ramp to move in TESB, but my bet is it's pretty low tech -- cable, pulleys, and an off-sreen forklift to provide power. From my days in prop and set work, these things were always the cheapest solution using whatever stage or construction gear was on hand.

Darth Humorous said:

Wow! Deja vu! Over a decade ago, I designed a couple of methods for the ramp moving mechanism that allowed the ramp to have a fixed hinge and the vertical “posts” to remain vertical and non-sliding laterally. The trick is in the joints where theses “posts” attach to the ramp itself. In my designs, these joints are not simple pivots.

I do not know what was actually done for the TESB set, but I think my designs are certainly reasonable solutions.

Click to expand...

Those sound like great engineering solutions! What scale did you make these to?

I tried making a sliding post design at 1/144, and it really didn't work. The movements tend to bind up at that scale.

Additionally, it's clear that the actual ESB sets didn't use sliding connection points - they had simple pivot mechanisms.



- nkg

Didn't one of the member here had a MF, on the Bespin platform? He rigged it with a raising ramp, it then hovered and rotated 90 degrees. Was a great build/effect.

joberg said:

Didn't one of the member here had a MF, on the Bespin platform? He rigged it with a raising ramp, it then hovered and rotated 90 degrees. Was a great build/effect.

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Are you thinking of this one?

https://www.youtube.com/watch?v=3zXUajjJCuo

In terms of the ramp, it seems the approach he took is to have the piston rods be fixed relative to the ramp, so they tilt.

nkg said:

Those sound like great engineering solutions! What scale did you make these to?

I tried making a sliding post design at 1/144, and it really didn't work. The movements tend to bind up at that scale.

Additionally, it's clear that the actual ESB sets didn't use sliding connection points - they had simple pivot mechanisms.

- nkg

Click to expand...

Unfortunately, the scale was for a “full size” falcon, and they never saw manufacture into hardware. It turns out that making the posts’ joints at the ramp “non-simple”, a variety of methods can be used. In addition to the slot (sort of a scotch yoke) and eccentric (a circular, off centered cam), linkages, gearing, pulleys/cable, and lead screws can be used. Of course the complexity is more.

Regarding the simple pivot mechanisms of the ESB set, I’m sure you’re right, though I am not entirely convinced about the ones at the very bottom, the ones in the “chunks”, as there is a significant open area in the “chunks” around the joints there. But then I don’t have good pix or the blu ray editions to see that area clearly. If there is a lateral motion of the bottommost posts as you suggest, I would think the post portion inside the hull would need hidden parallelogram linkages behind the walls. The interior post portion would make up the vertical, laterally moving, non-tilting section. For each post, there would need to be two long hidden pivoting arms attached to the top and bottom of this interior post portion, the other ends of said arms being on or near a vertical line that passes through the main ramp hinge line, attached to the wall somehow. These arms are parallel to each other and are roughly horizontal. I say “roughly” because they obviously have to tilt up and down. If you are right about the lateral motion of the posts, this may actually be what they did, in conjunction with something like an off camera crane to do the actual lifting, as you suggest. The only problem with this is that you might see two short lateral slots in the wall recess for the interior portion of the posts for the arm-to-post pivots to slide in. In a “real” Falcon, Im not sure how practical this parallelogram linkage method would be, but for a movie effect, it may be the most expedient.

Because of the long arms involved, this method might actually translate well scaled down to model size. However, the smaller the scale, the more of a watch maker you have to be.

Mark

Darth Humorous said:

Regarding the simple pivot mechanisms of the ESB set, I’m sure you’re right, though I am not entirely convinced about the ones at the very bottom, the ones in the “chunks”, as there is a significant open area in the “chunks” around the joints there. But then I don’t have good pix or the blu ray editions to see that area clearly.

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Yes, it's true there is an open area around the base of the frontmost pair of piston rods in the ESB and ROTJ versions of the ship (but not ANH) - something that hardly any model correctly replicates. You'd need a bit of open space if you had a pivot, but not as much as what they actually built. It's very difficult to see in the actual film footage owing to shadows, blowing smoke, etc. The best view I've seen of it is in a set photo from the unused Tatooine sandstorm scene from ROTJ, assuming the ramp base design is the same as ESB's.



However, I don't think that this opening was designed for a mechanism for lateral movement of the rods. The space slug scene in ESB clearly shows lateral movement of the piston rods inwards as the ramp descends, which wouldn't happen if you displaced the rod motion at the ramp connection point.



- nkg

nkg said:

However, I don't think that this opening was designed for a mechanism for lateral movement of the rods. The space slug scene in ESB clearly shows lateral movement of the piston rods inwards as the ramp descends, which wouldn't happen if you displaced the rod motion at the ramp connection point.
- nkg

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I’ve never discerned lateral movement of the rods, but then I wasn’t really looking for it. If you say you see it, I’ll take your word, as you seem to be a fellow rivet counter. They most certainly could have done it that way, and probably did. Next time I watch TESB, I’ll look for the lateral motion.

BTW, I made a boo boo in my previous post and only realized it when I went to bed. I had said: “The only problem with this is that you might see two short lateral slots in the wall recess for the interior portion of the posts for the arm-to-post pivots to slide in.” Actually, there would be two long, parallel arced slots running at a steep angle. I never saw such slots, so they probably used some other trick besides a direct parallelogram linkage to keep the posts vertical while they moved laterally. Maybe they set up a lateral motion of some kind using “the crane”. But for a scale model, such a parallelogram linkage is a sure fire way of achieving the kind of motion you are looking for.

I think the real problem is the “automatic” unfolding/folding of the step plate at the ramp’s bottom. We never see this action actually happening, but we do hear metal clanking when the ramp is down, and we never see any of the actors bend down to unfold it, much less fold it up after getting on the ramp to leave. I am certain that this was done by a person off camera. Even for a “full sized” Falcon, there is hardly any room for a robust mechanism to perform this function. And for a “full sized” Falcon, I had designed an axle with spur gears on either end that were to be within the “chunks”, to be driven with two motors, splitting the load in half. The max diameter of these gears were the same diameter as the axle, so the axle had to be turned down to receive the gears, and the gears and axle had to be tough. The bearings were outboard of the gears, and I used oil impregnated bushings to keep the diameter down. I think I used one or two idler gears to get some distance from the axle line where there was more room for the drive motors. Anyway, I’m not quite sure how to proceed for a scaled down model. This foot plate would need to swing something like 162 degrees from closed to open, and vice versa. There isn’t nearly that kind of angle to traverse within the chunks for linkages to be used (note that the axle is right in a corner). You may indeed be looking at using watch pinions for the axle and gear train, but the step plate itself had better be very light in weight.

Mark

Darth Humorous said:

I think the real problem is the “automatic” unfolding/folding of the step plate at the ramp’s bottom. We never see this action actually happening, but we do hear metal clanking when the ramp is down, and we never see any of the actors bend down to unfold it, much less fold it up after getting on the ramp to leave. I am certain that this was done by a person off camera.

Click to expand...

Actually I doubt they bothered.

In ANH the ramp obviously never moves, and so the bottom step is always permanently extended. In fact, it's a bit too wide, so it doesn't make much sense in terms of its design - how could it flip back on its simulated hinges given its excessive width?

In ESB the ramp moves but is never shown closed, and in fact always shown at least 2/3 of the way down already. And so the bottom step, though a more logical width, is always sticking out - on Hoth or the space slug. Or flipped up, as in the Bespin arrival scene.

- nkg

Well, at SOME point, SOMEONE had to fold it and unfold it because we see it unfolded when down on Bespin. Had it not been done, the actors would have stumbled over it on their way down the ramp onto the landing platform. But I know you are right in spirit. For example, they never bothered to close the belly blaster door after it was used when our heroes were trying to leave Hoth. And there it was, wide open inside the space slug.

Mark

Midway through this blog there is an animation of the boarding ramp. Definitely more of a hypothetical, but since there is no official ramp mechanism, I guess you'd be interested in hypotheticals.

http://millenniumfalcona.blogspot.com/2016/08/boarding-ramp.html?m=1

Jay's 3D animation is pretty awesome. It's based on a different assumption from my notes. He implements the idea of an extending ramp, versus laterally-shifting piston mechanisms.