PilotPete

Well-known member
First Name
Pete
Joined
May 8, 2023
Threads
5
Messages
640
Reaction score
1,557
Vehicles
Porsche, BMW
Occupation
Pilot
Country flag
Crabs don't use the word exoskeleton, either, I don't see how this argument is supposed to be compelling. That someone doesn't use a word doesn't mean it is or is not appropriate. Are there endoskeleton airplanes? Not really. So why would they make note of the difference?

-Crissa
You make the statement like there are only two options, if a plane is not Exo, then it must be Endo. There are many different ways to design a plane, and a car, annd a boat, and a helicopter, and…

And Crissa, really, crabs are talking to you now??? I gotta know, what are they telling you? C’mon man, you’re better than that.

I made the reply to this part of the post…
there are cars, planes, boats, that are built as an exoskeleton and recognized/discussed by designers and engineers as being exoskeleton construction as a category
And that isn’t true.
Sponsored

 

Crissa

Well-known member
First Name
Crissa
Joined
Jul 8, 2020
Threads
114
Messages
14,195
Reaction score
23,615
Location
Santa Cruz
Vehicles
2014 Zero S, 2013 Mazda 3
Country flag
Well, there's there 'we stretched a material over spars' (endo) and the 'we riveted panels together' exo.

Otherwise, it's not an air plane, it's something else. Rotocraft, lighter than air, etc.

And that's the point. Crabs don't talk. That a word applies is irrelevant to whether it's used by the in group or not.

-Crissa
 

CyberGus

Well-known member
First Name
Gus
Joined
May 22, 2021
Threads
53
Messages
4,107
Reaction score
13,252
Location
Austin, TX
Website
www.timeanddate.com
Vehicles
1981 DeLorean, 2023 Cybertruck
Occupation
IT Specialist
Country flag
Sure, but how will Tesla stop the scalpers from overcharging for the $100,000 exoskeleton that definitely was not not built in Austin?

(Sorry, just trying to combine all the irrelevant speculative topics.)
 

cvalue13

Well-known member
Joined
Aug 17, 2022
Threads
48
Messages
3,798
Reaction score
6,735
Location
Austin, TX
Vehicles
F150L
Occupation
Fun-employed
Country flag
You make the statement like there are only two options, if a plane is not Exo, then it must be Endo. There are many different ways to design a plane, and a car, annd a boat, and a helicopter, and…

I made the reply to this part of the post…


And that isn’t true.
I'm not sure I understand the response, sorry. But I have a strong feeling that we're merely in violent agreement.

While an imperfect category - there is a category of "exoskeleton vehicles" which design engineers well understand to be "exoskeleton" in their design - it's nearly extensive with *true* "monocoque* design (though the term 'monocoque' in automobiles is too frequently misapplied to what are actually unibody cars).

The Ariel Atom, the RC-3 Seabee, and any number of boats, other vehicles, are understood by these design engineers to be 'exoskeleton'/true monocoque vehicles - in as much as any such classification holds up under scrutiny.

Which gets us back to the point: vehicle engineers heard Musk say the CT would be "exoskeleton," and ran with those comments to mean he was talking about essentially a true monocoque/exoskeleton automobile, which while more widespread in race cars, planes, and boats, would be unusual and revolutionary for any production automobile.


Just go watch 2019/2020 videos of Sandy Munro comparing the purported CT design to the Seabee, etc., and I'm not sure how someone could disagree that professionals in vehicle/aerospace engineering didn't understand 'exoskeleton' as a category

they just misunderstood, perhaps, what Musk meant when he used the word
 

PilotPete

Well-known member
First Name
Pete
Joined
May 8, 2023
Threads
5
Messages
640
Reaction score
1,557
Vehicles
Porsche, BMW
Occupation
Pilot
Country flag
Well, there's there 'we stretched a material over spars' (endo) and the 'we riveted panels together' exo.

Otherwise, it's not an air plane, it's something else. Rotocraft, lighter than air, etc.

And that's the point. Crabs don't talk. That a word applies is irrelevant to whether it's used by the in group or not.

-Crissa
So, what do you call it when it is bonded with adhesive? What about Friction Stir Welding? What if the panels are not structural in one part of the aircraft, but are in another? What if there is skin that is riveted, in one part, but fabric over ribs in another part?

And to my original point, the designers and engineers never refer to them as exo or endo. That was the original claim to which I responded. I can tell you this because in my job, I meet with them on a regular basis. I’ve been involved in that end of the industry in different capacities for decades. Before that, I spent years buried in books studying aerospace engineering.

How do you figure that construction method has any bearing on whether it‘s an airplane or not? The method by which they achieve lift determines their category.

What I don’t understand is why do you appear to be so dead set on trying to prove exo v endo in my field? There are parallels and similarities in design, but nobody ever uses those terms, nobody.
 


cvalue13

Well-known member
Joined
Aug 17, 2022
Threads
48
Messages
3,798
Reaction score
6,735
Location
Austin, TX
Vehicles
F150L
Occupation
Fun-employed
Country flag
There isn’t a single plane out there I’ve ever seen that advertises they are built as an “Exoskeleton”. I’ve been in this business for a loooong time. I’ve been around boats a loooong time as well. Can’t think of one of them that uses that term.
I completely defer to your experience and expertise - just as I also completely defer to eg Sandy Munro's and other's experience and expertise. So with this collective experience, , i'll leave you experts to go duke it out - go see his 2019/2020 discussions of the CT and the Seebea

but as i mentioned in another post, i think that what's really going on here is merely violent agreement

to double-click: the underlying point was: when Elon said the word "exoskeleton" and then went on to describe what *he* meant by that term, professional vehicle engineers (across auto and aerospace) understood him to be talking about certain design/engineering principles that Musk was phrasing as 'exoskeleton'

from that collective information, folks like Munro interpreted "exoskeleton" in this context to mean a suite of features and parameters that were understood based on Musk's description

I appreciate that the above isn't exactly how i phrased it earlier, but I'm fatally caught between a desire to be as brief as possible and a countervailing desire to write for hours on end

baby is often split
 

cvalue13

Well-known member
Joined
Aug 17, 2022
Threads
48
Messages
3,798
Reaction score
6,735
Location
Austin, TX
Vehicles
F150L
Occupation
Fun-employed
Country flag
What I don’t understand is why do you appear to be so dead set on trying to prove exo v endo in my field? There are parallels and similarities in design, but nobody ever uses those terms, nobody.
with apologies, I am literally unable to tell if your comments are directed towards me unless you've actively quoted me

the reason is, there are a few members in the forum who have me blocked (it's mutual), and so that means you *could* be responding to one of them but I can't see the discussion (or if you have quoted them)

very clunky and frustrating
 

PilotPete

Well-known member
First Name
Pete
Joined
May 8, 2023
Threads
5
Messages
640
Reaction score
1,557
Vehicles
Porsche, BMW
Occupation
Pilot
Country flag
I'm not sure I understand the response, sorry. But I have a strong feeling that we're merely in violent agreement.

While an imperfect category - there is a category of "exoskeleton vehicles" which design engineers well understand to be "exoskeleton" in their design - it's nearly extensive with *true* "monocoque* design (though the term 'monocoque' in automobiles is too frequently misapplied to what are actually unibody cars).

The Ariel Atom, the RC-3 Seabee, and any number of boats, other vehicles, are understood by these design engineers to be 'exoskeleton'/true monocoque vehicles - in as much as any such classification holds up under scrutiny.

Which gets us back to the point: vehicle engineers heard Musk say the CT would be "exoskeleton," and ran with those comments to mean he was talking about essentially a true monocoque/exoskeleton automobile, which while more widespread in race cars, planes, and boats, would be unusual and revolutionary for any production automobile.


Just go watch 2019/2020 videos of Sandy Munro comparing the purported CT design to the Seabee, etc., and I'm not sure how someone could disagree that professionals in vehicle/aerospace engineering didn't understand 'exoskeleton' as a category

they just misunderstood, perhaps, what Musk meant when he used the word
I’m with ya now. But I will stand behind the statement that no one in aviation engineering uses the term Exoskeleton, even if, like the SeaBee, they use a thick skin in place of ribs. Look at the XB70A, Rockwell created an aluminum honeycomb with a bonded outer aluminum skin as a structural outer member. But nobody at Rockwell ever used the Exo term. And the entire plane wasn’t built that way.

One of the assumptions made here about the BIWs is that we see all that is “structural”. It is possible that the methods by which the 30X is added to the rear make them stronger, and thereby make them structural components. Even a modern car uses the doors as structural. Anyone that has ever driven a convertible knows the roof of a coupe or sedan is structural and the convertible tries to compensate in other ways.

I’m with you 100% that how EM used the term may not be how everyone is assuming the design “must” be. I also have to assume that if the sails and bed are made of 30X that thick, they are not attached with plastic clips and rubber grommets. Those bad mamajamas are adding to the structural stiffness of the whole vehicle. Why do I assume that? The crabs told me! (Props to my brother nerd Crissa!)

I think we are on the same page C. Next adult beverage is on me.
 

PilotPete

Well-known member
First Name
Pete
Joined
May 8, 2023
Threads
5
Messages
640
Reaction score
1,557
Vehicles
Porsche, BMW
Occupation
Pilot
Country flag
with apologies, I am literally unable to tell if your comments are directed towards me unless you've actively quoted me

the reason is, there are a few members in the forum who have me blocked (it's mutual), and so that means you *could* be responding to one of them but I can't see the discussion (or if you have quoted them)

very clunky and frustrating
I never considered that. Sorry. I was responding to Crissa more than you. That‘s where the crab discussion and snarky comments came from.

We’re good my brother. Drinks on me.
 

Ogre

Well-known member
First Name
Dennis
Joined
Jul 3, 2021
Threads
163
Messages
10,710
Reaction score
26,921
Location
Ogregon
Vehicles
Model Y
Country flag
There isn’t a single plane out there I’ve ever seen that advertises they are built as an “Exoskeleton”. I’ve been in this business for a loooong time. I’ve been around boats a loooong time as well. Can’t think of one of them that uses that term.
Musk used aircraft as an example of how the Cybertruck integrated structure and the skin of the vehicle.

Nobody in the AUTO industry has used the term exoskeleton either so people arguing over whether the Cybertruck does or doesn’t match the definition of the term when it’s never been used in this context is a giant joke.

Cybertruck is the first and only vehicle which is an exoskeleton body. What is an exoskeleton vehicle? Look at the Cybertruck.
 


cvalue13

Well-known member
Joined
Aug 17, 2022
Threads
48
Messages
3,798
Reaction score
6,735
Location
Austin, TX
Vehicles
F150L
Occupation
Fun-employed
Country flag
But I will stand behind the statement that no one in aviation engineering uses the term Exoskeleton, even if, like the SeaBee, they use a thick skin in place of ribs.
oh man, you either gonna *love* or *hate* this post of mine from a while back

in that post, I’m basically playing Musk apologist by laying out a view that:

• Musk’s comments on stage about what he meant by the term “exoskeleton” were quite fairly interpreted by auto/aero engineers to mean one thing (basically a true monocoque construction, but applied to a a production vehicle)

• those auto/aero engineers then ran around in 2019/2020 telling people their interpretation

• later, we saw the CT’s castings+cab chassis and regular folks started squawking “but that’s not an exoskeleton, Musk lied!”, all based on what the auto/aero engineers had interpreted and propagated as Musk’s meaning of the term “exoskeleton”

• but that fundamentally, so the post argues, those auto/aero engineer’s interpretation was wrong, and there are still sensible ways that Musk’s description of an “exoskeleton” is defensible and simply was misinterpreted

• and so as a result, the CT is possibly every bit as much of an “exoskeleton” as he described in 2019, and it’s not on Musk if it’s not the type of “exoskeleton” people had come to expect based on auto/aero engineers misinterpreting the term “exoskeleton”

second beer’s on me
 

firsttruck

Well-known member
Joined
Sep 25, 2020
Threads
146
Messages
2,321
Reaction score
3,652
Location
mx
Vehicles
none
Country flag
Sorry C, you overstepped there.

There isn’t a single plane out there I’ve ever seen that advertises they are built as an “Exoskeleton”.

I’ve been in this business for a loooong time. I’ve been around boats a loooong time as well. Can’t think of one of them that uses that term.

As far as designers and engineers, I can tell you in the aviation field, NO ONE uses that term. Mostly because they really aren’t built that way. A ribbed structure is built first and the outer skin is attached (method varies with size and cost) to the frame. The inner skin is different, as it forms the “pressure vessel” of the aircraft. It’s still bonded to the frame, but sometime by a different method than the outer skins. On most jets, the outer wing skins (there being no inner skin on the wing) also forms the fuel tanks, and the structure inside is continuously bathed in Jet-A fuel.

Non-pressurized aircraft reduce weight by making the inner fuselage skins out of plastic or something else. Of course, Carbon Fiber and other composite materials are becoming more and more common in design and manufacturing.

In the late 80’s and 90’s, crotch rockets (performance motorcycles) started using the phrase (and design concept) of the engine and transmission as a “stressed member”, meaning, the frame bolted to the engine and gained strength and rigidity from the engine itself. Yamaha built a frame that was two aluminum spars that directly connected the steering head to the swing arm pivot in a straight line (when viewed from the side.) and the engine bolted directly to the frame to provide strength.

Boats are often a frame (wood, aluminum, steel, or composite) which is placed in a mold and additional composite material is then laid in and baked under pressure to form the outer hull. The top section is molded separately and attached, allowing the company to offer different versions of the same hull (center console, max sleeper, performance cruiser, all out performance) for the public.

But even if you consider them to be exo designed, they don’t use the term.
Just because products don't tout or advertise they are exoskeleton doesn't mean that there have not been any.

I don't think exoskeleton or endoskeleton were terms used by aircraft industry in 1940s when Republic Aircraft RC-3 Seabee was built but Sandy Munro believes the RC-3 is an example of exoskeleton design in an aircraft.

Munro & Associates claims to have help design and produce actual flying prototype (not just a non-working prototype) of a autonomous plane in 2007/8 that was of exoskeleton design. Plane was called Paradigm.

--------------------------


Sandy Munro Thinks Cybertruck Will Be A Cash Cow For Tesla
The tooling costs for it are probably just a fraction of what they would be for a regular truck.


Tesla Cybertruck Cybertruck BIW body-in-white frames with front/rear castings 🤩 [7/11/23] 1689371037449



------------


video cued to Cybertruck, exoskeleton, weight savings, Seabee, Munro prototype exoskeleton plane (Paradigm).

picture above is at time 14:40


Deconstructing The Tooling Cost on Tesla’s Cybertruck - Autoline After Hours 492
Autoline After Hours GUEST: Sandy Munro, Munro & Associates
PANEL: Frank Markus, Motor Trend; Gary Vasilash, Automotive Design & Production; John McElroy, Autoline.tv
Streamed live on Jan 16, 2020
Autoline Network



--------------------------

video cued to Elon speaking about Cybertruck, exoskeleton and Sandy adds comments.

Munro prototype exoskeleton plane (Paradigm) weighed less, easier to assembly.
Tried to get legacy auto to make car based on exoskeleton structure.

** Also Elon said Cybertruck 3mm stainless steel would be bulletproof to handgun and low voltage wiring of 48V with both power & data (like PoE, power over Ethernet).

Third Row Tesla Podcast Episode 14 - Tesla Manufacturing with Sandy Munro and Elon Musk!
Video recorded 9th April, 2020
Apr 14, 2020
Third Row Tesla



--------------------------

** Munro Paradigm plane steering was by joystick. Sandy says use joystick to steer car.

Tips for Tesla E1 - Steering and Weight Reduction
Episode 1: This is the first of several videos where Sandy offers some tips on different things Tesla should focus on implementing in the future. Some of the ideas will be straightforward and some may be a little off-the-wall but the content is delivered in classic Sandy fashion.
Jul 8, 2020
Munro Live



--------------------------
 
Last edited:

PilotPete

Well-known member
First Name
Pete
Joined
May 8, 2023
Threads
5
Messages
640
Reaction score
1,557
Vehicles
Porsche, BMW
Occupation
Pilot
Country flag
Just because products don't tout or advertise they are exoskeleton doesn't mean that there have not been any.

I don't think exoskeleton or endoskeleton were terms used by aircraft industry in 1940s when Republic Aircraft RC-3 Seabee was built but Sandy Munro believes the RC-3 is an example of exoskeleton design in an aircraft.
FT, Please look at the entire discussion. I said the part I objected to was that in aviation, designers and engineers don’t use that term. The original post I referred to stated that they did. Plain and simple, that’s what I said. Sure, I went in a whole bunch of other directions in the description (kinda like I’m doing now) and somehow we even got into talking crabs. I tried to show there are varying levels of Exo, it’s not an all or nothing design concept. But the original objection was over the use of the term in aviation design. The teams at Lockheed, Boeing, Northrop, General Dynamics, Textron, Bombardier, Cirrus, Scaled Composites, etc. don’t use that term. And look, there are planes out there right now that strictly fit the definition, but the term isn’t used. I’m about to apply for 3 more patents. I won’t use the term either. (Mostly because I don’t want anything based on my design to be nicknamed a crab or a lobster!) I mean, are the Taliban going to be afraid of the new US Fighter/Bomber, the F/A-99 Softshell Crab??? Or the B-55 Langostino?

I think Lockheed might have a design patent suit for the profile of the CT. I mean, look at this! (Tongue in cheek) Take the tail off and it’s the top of the CT! Come to think of it, maybe I could mount a V tail on my CT and…

Tesla Cybertruck Cybertruck BIW body-in-white frames with front/rear castings 🤩 [7/11/23] IMG_2502
 

cvalue13

Well-known member
Joined
Aug 17, 2022
Threads
48
Messages
3,798
Reaction score
6,735
Location
Austin, TX
Vehicles
F150L
Occupation
Fun-employed
Country flag
I said the part I objected to was that in aviation, designers and engineers don’t use that term. The original post I referred to stated that they did.
Yes, I sure had, and to that point you are absolutely right:

there are cars, planes, boats, that are built as an exoskeleton and recognized/discussed by designers and engineers as being exoskeleton construction as a category…

this “exoskeleton” concept in building vehicles is understood, predating Musk’s comments on stage, and professionals who understood this concept thought Musk was talking about something different
If at reveal Musk had said only the word “exoskeleton” and moved on, designers/engineers wouldn’t have known quite what he might be referring to. As @PilotPete points out.

But Musk went on to describe the substance of what he meant by that term, which substance described that which seemed to engineers/designers to be a familiar and recognizable category of construction:

“We’re able to achieve much greater capability in the same dimensions, same weight. Yeah. Part of this is the fundamental design change, we moved the mass to the outside. We created an exoskeleton.
So normally the way that a truck is designed, you have a body on frame, you have a bed on frame and the body and the bed don’t do anything useful. They’re carried like cargo, like a sack of potatoes. It was the way that aircraft used to be designed, when they had biplanes, basically. The key to creating an effective monoplane was a stressed skin design. You move the stress to the outside skin. Allows you to do things that you can’t do with a body on frame. So we’re able to make the skin out of thick, ultra hard stainless steel. It’s really hard.”

Folks like Sandy Munro based on the above characterizations, many fairly understood Musk to be describing a (true) monocoque design like that used in airplanes - using stressed skin as the main or entire structural component.

It is *that* concept - this definitional description - that I intended to mean was “recognized/discussed by designers and engineers as being [exoskeleton] construction as a category.”

Why wouldn’t Musk instead have just called it “monocoque,” though?

One reason might be that while true monocoque isn’t seen in a production automobile, the *term* “monocoque” is often colloquially but inaccurately applied to what are strictly speaking unibody constructions.

Had Musk on stage described the CT as a “monocoque” design, it would have been as good as saying the CT was “unibody” in design.

He needed a word that would communicate the uniqueness of “(true) monocoque in a production vehicle” but that wouldn’t just be confused with unibody construction.

And designers/engineers well versed in both automobiles and aeroplanes were happy to run with Musk’s term. And to also tell everyone that what Musk meant by that term was [insert their interpretation of Musk’s comments].

In any event, what is fair to say: given the substance of what Musk described on reveal night, it sure seems that many seasoned auto/aero engineers took Musk to be describing something other than what we now see in these photos.

And I empathize!

But to be fair also to Musk, he can still fairly call the CT an “exoskeleton” given the lack of definitional meaning of the *term* alone - like @PilotPete points out.

Separate from that, what my prior comment was intending to point out: beyond the term used, what Musk appeared to designers/engineers to be describing on stage (eg the type of true monocoque construction used in planes, etc.) does have a known/recognizable construction, which isn’t up to Musk.
 

cvalue13

Well-known member
Joined
Aug 17, 2022
Threads
48
Messages
3,798
Reaction score
6,735
Location
Austin, TX
Vehicles
F150L
Occupation
Fun-employed
Country flag
Just because products don't tout or advertise they are exoskeleton doesn't mean that there have not been any.

Munro & Associates claims to have help design and produce actual flying prototype (not just a non-working prototype) of a autonomous plane in 2007/8 that was of exoskeleton design.
Munro (and his colleagues) in particular do run with the term “exoskeleton” a lot. I don’t know if this flu rushed only after the introduction by Musk to the Munro vocabulary.

Munro worked Aptera, and calls it an “exoskeleton.”

Munro for a long while took to calling the CT an “exoskeleton unibody.”

But quoting Munro and associates for this position of yours is rather odd, given that since seeing the CT BIW it’s their top dogs who looked at it and said…

“that is not an exoskeleton construction”

(before the dogs are unleashed, I’m not siding with Munro on this, I’m just reporting)
Sponsored

 


 


Top