24 replies to this topic

[Catch 22]

Pretty simple request here: I've read the term "tank slapper" a bunch of times now, and I'm still not sure exactly what it means.

Would somebody please tell me what defines a "tank slapper"?

Many thanks in advance!

[Uncle Davy]

The phrase is generally used to describe an accident where the car impacts a wall or barrier broadside, often after spinning 180 degrees. The term is now pretty much an anachronism since few, if any, modern racing cars carry fuel in sidepod tanks.

[David McKinney]

On this side of the pond the term is very rare outside motorcycle-racing circles

[Uncle Davy]

Still used quite frequently during the month of May in my neck of the woods...;)

[Racer.Demon]

For cars I've heard an explanation that is very much different from that of Uncle Davy's, and quite similar to what's happening to motorcycles when their riders suffer a tank slapper.

I understand that it has to do with the fuel rushing to one side of the tank when coming out of a corner, causing the weight balance of the car to suddenly shift, resulting in massive oversteer since the tank is usually located at the back of the car. It forces the driver to respond instantaneously to the car snapping away underneath him. The resulting view from the outside is that of a big wobble before the car straightens itself out.

To prevent this from happening and create a better balance, today's racing cars have their fuel contained in small but connected fuel cells rather than one big tank, thus stopping the fuel from rushing in every direction along with the centrifugal forces on the car.

[Ray Bell]

These responses amaze me, for I had always thought (because I got the phrase from a motorcycle racing friend, and have heard it virtually nowhere else for years) that it referred to 'slapping' the tank with your hands as you correct and re-correct an errant motorcycle.
While I'm sure the other explanations make some sense, I think this one will stand up much better.

[Rainer Nyberg]

I also recall the term as a big moment with a car or motorcycle from where you actually did recover...
Like a massive half-spin...

Rainer

[Ray Bell]

The term might be used as such, but only erroneously.
It clearly indicates a backwards and forwards motion, overcorrecting and correcting again...

[Mike Argetsinger]

Irrespective of its original derivation - the way the term is generally used today is to describe what Ray says - "backwards and forwards, motion, overcorrecting and correcting again" --- but Rainer is partly right too in that it means "a big moment ... from which you actually did recover."

Perhaps the term does mean different things to different people both regionally and depending on the form of motorsport. But in car racing circles I have been hearing it for some time now to describe what Ray and Rainer said.

[Uncle Davy]

The term may have different meanings when applied to various forms of motor racing in different parts of the world; but as I stated above, come to Indianapolis in May and you will be guaranteed to hear it in the context I described.

But as everyone knows, we Hoosiers are such provincial bumpkins...

Oh well, back to the Paddock Club...

[Ray Bell]

Watch it, my son is there!

Can't agree with any view that it might be the fuel tanks slapping against any wall. Purely misapplied.

[Uncle Davy]

Fine, Ray, you win...either I made it up or I've just been suffering from aural hallucinations all these years...sjeez...

[Ray Bell]

I'm not saying it isn't said, but as I do say, I think it's being misapplied.

[MoMurray]

Some years ago, I learned first hand the meaning of tank slapper. It is a term derived from motorcyling and it refers to the unfortunate circumstance of having the fuel tank of a motorcycle slap your knees one after the other in quick succession. Not so terrible I hear you say...let me assure you that in most cases, it will not occur at slow to moderate speed and it is usually followed by a rapid skyward departure from the motorcycle. My "research" on the subject took place about fourteen years ago on a German autobahn...at midnight...at 125mph. I have stretch marks from the pucker I can tell you. I still vividly remember flying through the air thinking "oh ****...this is going to hurt!". I was not wrong. Much to my mothers chagrin, immediately following my several months of rehab (Tib/Fib compound break, hand broken, lots of skin and one of my knuckles missing) I remounted that proverbial horse. My first ride following the tank slapper and it's aftermath was on a Honda Hurricane 1000 around all fourteen miles of the old nurburgring. Ooh I felt alive that day...

[MoMurray]

BTW the part between the tank slapper and the skygroundskygroundskyground is affectionately know as a "Flying W". It only applies to male riders...if you get my drift...

[Ross Stonefeld]

I thought maybe a tank slapper had something to do with the bike touching the ground whilst cornering, as opposed to simply losing one of the wheels

[Racer.Demon]

Originally posted by MoMurray
It is a term derived from motorcyling and it refers to the unfortunate circumstance of having the fuel tank of a motorcycle slap your knees one after the other in quick succession. Not so terrible I hear you say...let me assure you that in most cases, it will not occur at slow to moderate speed and it is usually followed by a rapid skyward departure from the motorcycle.

Originally posted by Rainer Nyberg
I also recall the term as a big moment with a car or motorcycle from where you actually did recover... Like a massive half-spin...

I'd say Mo and Rainer are talking about the same thing - Mo is discussing it from the view of the rider, while Rainer describes the way it looks from a distance.

The racing car equivalent described by me falls into this line.

Originally posted by Racer.Demon
I understand that it has to do with the fuel rushing to one side of the tank when coming out of a corner, causing the weight balance of the car to suddenly shift, resulting in massive oversteer since the tank is usually located at the back of the car. It forces the driver to respond instantaneously to the car snapping away underneath him. The resulting view from the outside is that of a big wobble before the car straightens itself out.

To prevent this from happening and create a better balance, today's racing cars have their fuel contained in small but connected fuel cells rather than one big tank, thus stopping the fuel from rushing in every direction along with the centrifugal forces on the car.

It has a different physical cause but the result is the same - a sudden shift of weight leading to a huge loss of balance - and it looks fairly similar from the outside: a huge oversteer, overcorrecting and correcting again, conforming with Ray's idea. The difference between a two-wheel and four-wheel tank slapper is that a biker is usually thrown off his bike quite violently, as described by Mo, and only on occasion manages to recover from what looks like a big wobble of the bike, followed by a violent snap of the frame in the opposite direction. Since a bike is a vehicle that is totally depending on balance it's near impossible to recover from such a moment. Racing drivers don't tend to get thrown out of their cars... although they sometimes end up pointing their noses in another direction.

Originally posted by Ray Bell
It clearly indicates a backwards and forwards motion, overcorrecting and correcting again...

So we all mean the same thing - except for Davy of course…;)

[Ray Bell]

My concern here is to go to the source of the expression, which is clearly motorcycles.
I think fuel slopping round in a tail tank has little real prospect of being seriously considered so...

[desmo]

Ray is right. It refers to an uncontrolled oscillation of the front wheel of a motorcycle. With "clip-on" handlebars as used in road racing it would result in literally "tank slapping". With the advent of increased stanchion tube diameters, well reinforced steering heads and effective steering dampers this phenomenon is thankfully much rarer now. Instead, modern bikes are more likely to go straight into a "high side" which is another- unpleasant- story.

[jmcgavin]

Hence the confusion on my part as several commentators seem to be referring to a high side and saying 'that was a real tank slapper'

[karlcars]

I'm not sure of the derivation but in car racing the term refers to a situation in which the car has suffered a slide at the rear which the driver has caught but in a way that provoked a slide in the other direction, and on and on until he got the car under control. It can also end with the car out of control as once happened to me at Shelsley Walsh!

Here's the way Dan Gurney described one such incident to me: "Before Becketts [at Silverstone] on the left hander, I was going around and it had been raining, and there were puddles and I hit a puddle, just the next thing I was doing a tank slapper and I was trying to keep up, you know, still fighting for control. It didn't go off the road or anything but I was unable to wrest the fastest lap back from Stirling again."

Then at the 'Ring Dan described this encounter with Denny Hulme:

"Denny had a monumental tank-slapper in one particular place. After that bridge you went up a little right and then down to a right-hand turn which is where, I think, Godin de Beaufort was killed. Then it started to climb up through there. You were going fast and it was up in one of those sections [that] he hit a puddle of water and he lifted big time and that was it. At that time I had a 43 second lead with about three laps to go."

In both cases the driver recovered the car but not until he got to grips with an oscillating rear-end slide. We would also call it 'fishtailing', of which the derivation is obvious.

[Eric McLoughlin]

As far as cars are concerned, I've also heard of the expression "fishtailing" which seems to apply to the same circumstances ie. when the rear end of the car swings from one side to the other in rapid succession. It's caused when the driver overcompensates for an initial slide, usually caused by applying power too early when exiting a bend or corner. A similar phenomemon exists in aviation circles where it is referred to PIO (pilot induced oscilation).

[Catch 22]

Many thanks, all! I understand both the origin and current use of the term much better now.

Karl, as it happens, it was Gurney's use of the term (as quoted in your "Ultimate Racer") which actually precipitated my question. I thought I probably knew what it meant based on his description of the incident with the Bear at the Ring, but I couldn't figure out what exactly it had to do with slapping a tank! I've always used the term fishtailing (or my very own version, "taking a ride with Mr. Toad") to describe the same thing.

And Uncle Davy, if it makes you feel any better at all, I too have heard the Indy version, but it made no sense in the context of the quote from Our Man Dan.

[Uncle Davy]

Thanks for the edification, one and all...amazing what an education one can get from posting a wrong answer (and I am being sincere here, as opposed to my Paddock Club personum).

The Dan Gurney quote was definitive for me, with all due respect to the resident sages...who am I to contradict my childhood hero?

Come May, I may have to go out to IMS and slap Tom Carnegie upside the head (oops, I think he retired).

Hope I didn't embarass myself too much due to my ignorance...I'll just use the phrase that has kept my marriage together for eleven years..."I was wrong".

[fines]

Indy without Tom "Heee's onit" Carnegie? Unthinkable, isn't it?