Front engine safer than rear?

[XJ Flyer]

Mave said:

XJ Flyer said:

All of which is based on the flawed idea that the Westminster is just a solid lump with no crumple ability of it's own.Everything after that is about defeating the other car and using that as a reserve crumple zone

Why are you obsessed with "defeating" the other car? The reason the "shopping car" protected the occupants better than the Volvo was simply because it's crumple zone was more effective. If the Westminster had better packaging with regards to crumple zones, it too would protect its occupants better.

No the reason why the transverse engined car performed better was because the combination of engine and bulkhead went through the Volvo's combination of front wing structure and exposed bulkhead like a knife through butter.

[SkinnyP]

Gen 2 911 vs E90 3 series, it's a mess although the engine in the 911 looks nicely preserved.

https://www.youtube.com/watch?v=bDyvOGW_80o

[XJ Flyer]

shoestring7 said:

blueg33 said:

Someone has compared having ab engine in front of you as being like having a wall in front of you = safer

I don't get that, because what we should have here as an analogy, is a wall that can be pushed over onto you. Would you rather be behind a wall that can be pushed on top of you, or have specially designed features to ensure that arrows are defected anyway and no wall to squish you?

Personally, the impact on the body, especially legs of an engine being pushed backwards into the passenger compartment doesn't bear thinking about.

Or.. "If I was to drop you onto a pile of cardboard boxes, would you prefer them to be empty or full of nice strong bricks?"

SS7

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

[Mave]

XJ Flyer said:

I 'actually' said in the case of any longitudinal v transverse offset collision it won't be so easy to reach any conclusions regarding the performance of the longitudinal layout.

You 'actually' also said that you'd prefer to be in the tank

[XJ Flyer]

SkinnyP said:

Gen 2 911 vs E90 3 series, it's a mess although the engine in the 911 looks nicely preserved.

https://www.youtube.com/watch?v=bDyvOGW_80o

No doubt saved by the crumple zone that was designed to absorb the impact.

[Mave]

XJ Flyer said:

Ironically because the transverse design trades crumple zone for the battering ram and barrier capabilities of the lump of engine block ahead of the bulkhead.In order to defeat the crumple zone and exposed bulkhead area of the longitudinal layout.

The Volvo effectively has no crumple zone. The layout means if the engine takes the hit then there's no room for it to absorb the impact before encroaching the cabin, and if the engine doesn't take the hit then there isn't sufficient structure to spread the load.

[XJ Flyer]

Mave said:

XJ Flyer said:

I 'actually' said in the case of any longitudinal v transverse offset collision it won't be so easy to reach any conclusions regarding the performance of the longitudinal layout.

You 'actually' also said that you'd prefer to be in the tank

In a square on head on collision.

Not an offset one in which case the odds won't be so good.Ironically because that would be a case of longitudinal layout front wing crumple zone and exposed bulkhead v tranverse engine and bulkhead combination.Which still then leaves the question of the ultimate strength of the transverse layout v the tank's wing and bulkhead structure.In which case the tank doesn't get much better than an old Westminster or an XJ in that regard.

[Mave]

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

[XJ Flyer]

Mave said:

XJ Flyer said:

Ironically because the transverse design trades crumple zone for the battering ram and barrier capabilities of the lump of engine block ahead of the bulkhead.In order to defeat the crumple zone and exposed bulkhead area of the longitudinal layout.

The Volvo effectively has no crumple zone. The layout means if the engine takes the hit then there's no room for it to absorb the impact before encroaching the cabin, and if the engine doesn't take the hit then there isn't sufficient structure to spread the load.

In which case why not try the same test in the square on scenario and see what happens.By your logic the Volvo's engine would kill the Volvo's bulkhead.While by mine the loads would then be spread across the front and amongst both wing structures and the engine and bulkhead structure.In which case I'd guess that the front of the Volvo would penetrate the shopping car's bulkhead before vice versa.Although assuming the 7 series Volvo still failed in that regard trust me a 140 series wouldn't.

www.youtube.com/watch?v=029nFGSzZZY

Edited by XJ Flyer on Friday 29th August 20:08

[XJ Flyer]

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

[Mave]

XJ Flyer said:

Mave said:

XJ Flyer said:

I 'actually' said in the case of any longitudinal v transverse offset collision it won't be so easy to reach any conclusions regarding the performance of the longitudinal layout.

You 'actually' also said that you'd prefer to be in the tank

In a square on head on collision.

So you'd rather have your rigid engine hit the other car then punch back into your cabin, leaving you to palm it off with one arm, whilst fending off the other car's transverse engine with your feet because your lack of a seriously rigid full width load spreading member (engine) means there's no effectice way of distributing the loads into the structure?

[Mave]

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

[Mave]

XJ Flyer said:

Mave said:

XJ Flyer said:

Ironically because the transverse design trades crumple zone for the battering ram and barrier capabilities of the lump of engine block ahead of the bulkhead.In order to defeat the crumple zone and exposed bulkhead area of the longitudinal layout.

The Volvo effectively has no crumple zone. The layout means if the engine takes the hit then there's no room for it to absorb the impact before encroaching the cabin, and if the engine doesn't take the hit then there isn't sufficient structure to spread the load.

In which case why not try the same test in the square on scenario and see what happens.By your logic the Volvo's engine would kill the Volvo's bulkhead.

yep, if you mean the engine is essentially back in the cabin and performing no further crash protection function

XJ Flyer said:

While by mine the loads would then be spread across the front and amongst both wing structures and the engine and bulkhead structure.

Are you talking about the load from the transverse engine onto the front of the Volvo?
In which case, you've now trying to transfer point loads from the transverse engine into the Volvo front and wings in an uncontrolled manner, rather than designing an effective and stable load path.

[XJ Flyer]

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

That logic seems to be from the Volkswagen Beetle school of car design theory to me.

[Mave]

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

That logic seems to be from the Volkswagen Beetle school of car design theory to me.

Is there anything wrong with it?

[XJ Flyer]

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Ironically because the transverse design trades crumple zone for the battering ram and barrier capabilities of the lump of engine block ahead of the bulkhead.In order to defeat the crumple zone and exposed bulkhead area of the longitudinal layout.

The Volvo effectively has no crumple zone. The layout means if the engine takes the hit then there's no room for it to absorb the impact before encroaching the cabin, and if the engine doesn't take the hit then there isn't sufficient structure to spread the load.

In which case why not try the same test in the square on scenario and see what happens.By your logic the Volvo's engine would kill the Volvo's bulkhead.

yep, if you mean the engine is essentially back in the cabin and performing no further crash protection function

XJ Flyer said:

While by mine the loads would then be spread across the front and amongst both wing structures and the engine and bulkhead structure.

Are you talking about the load from the transverse engine onto the front of the Volvo?
In which case, you've now trying to transfer point loads from the transverse engine into the Volvo front and wings in an uncontrolled manner, rather than designing an effective and stable load path.

Which leaves the question 'if' you are right why keep pushing the offset longitudinal v transverse scenario when the square on one would,supposedly,have the same result.

I'm talking about a square on head on test rather than an offset one.In which case there's 'more chance',by no means guaranteed,that the longer and more effective crumple zone in the form of both front and inner wings and the combination of engine and bulkhead.Will probably penetrate the shorter crumple zone and engine and bulkhead combination of the transverse layout before the bulkhead fails on the longitudinal design.

IE in most cases,certainly in the case of a small hatch,the longitudinal design simply has more metal in front of the bulkhead.

The key as usual being the ability for the engine in whatever form to add to the penetrative value of the crumple zones v the opposing car's not just being a barrier against it.Hence the idea of the rear engined car being just about the worst possible choice from that point of view.

[XJ Flyer]

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

That logic seems to be from the Volkswagen Beetle school of car design theory to me.

Is there anything wrong with it?

That is the question.So far we've at least got one bit of photographic evidence which doesn't look good for the rear engined idea.

[Mave]

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

That logic seems to be from the Volkswagen Beetle school of car design theory to me.

Is there anything wrong with it?

That is the question.So far we've at least got one bit of photographic evidence which doesn't look good for the rear engined idea.

So you've answered the question with an example which doesn't fit the criteria? BMW 3 series hardly being transverse engined.

[XJ Flyer]

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

That logic seems to be from the Volkswagen Beetle school of car design theory to me.

Is there anything wrong with it?

That is the question.So far we've at least got one bit of photographic evidence which doesn't look good for the rear engined idea.

So you've answered the question with an example which doesn't fit the criteria? BMW 3 series hardly being transverse engined.

I've actually said that it's all about the engine playing a part in acting as a barrier and/or penetrating the opposing car's bulkhead.The BMW's front engined layout seems to have done exactly that in penetrating the 911's bulkhead,at least further,in the example in question.Just as the transverse engined layout did in both acting as a barrier and penetrating the Volvo's bulkhead in the case of the offset test with the longitudinal front engined Volvo.

Edited by XJ Flyer on Friday 29th August 22:13

[Mave]

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Mave said:

XJ Flyer said:

Or would would you prefer to be sitting in a cardboard box on wheels and then drive it head on at a combined speed of around 80 mph + into a front engined car.Although to make it fairer you can have 50 feet of carboard box ahead of you and I'll settle for around the 2 feet of combined crumple zone and engine and bulkhead of the Zafira.

Why can't both drivers have 2' of steel crumple zone?

Fair enough you can have 2 feet of steel crumple zone without an engine and I'll have the same with a transverse engine sitting in front of the bulkhead.

Great! Lets try a thought experiment.
We've both got cardboard boxes. You've also got a steel plate.
I hold my cardboard box in front of me. You do the same. You can hold your steel plate either in front of, or behind, the cardboard box.
We run hard at each other and collide. Are you any better off than me because you were holding the steel plate not me?

That logic seems to be from the Volkswagen Beetle school of car design theory to me.

Is there anything wrong with it?

That is the question.So far we've at least got one bit of photographic evidence which doesn't look good for the rear engined idea.

So you've answered the question with an example which doesn't fit the criteria? BMW 3 series hardly being transverse engined.

I've actually said that it's all about the engine playing a part in acting as a barrier and/or penetrating the opposing car's bulkhead.The BMW's front engined layout seems to have done exactly that in penetrating the 911's bulkhead,at least further,in the example in question.Just as the transverse engined layout did in both acting as a barrier and penetrating the Volvo's bulkhead in the case of the offset test with the longitudinal front engined Volvo.

Edited by XJ Flyer on Friday 29th August 22:13

But, as I said, its actually about distributing load through the crumple zone. Actually, while the engine playing the part of load distribution in the transverse layout, further longitudinally concentrates it's force. The engine is stiff, so to the point in question, the BMW penetrates the crumple zone, but the Volvo to the point in question defeats the opponent's crumple zone. Further, in the offset test in question, the 911 defeat's the BMW's bulkhead.