The thing I hate about an
argument is that it always interrupts a discussion.
G. K. Chesterton (1874 - 1936)
Maxim
J&J
We
picked up this Maxim chassis in the fall of 2004. It was a 3 year old car, like
new, straight and had no damage. It came from the owner of the Petty Driving
Experience and had been sitting idle for 2 years after only a dozen races with USCS in
GA.
It was mid July when I took a high flying ride, 25 ft in the air at
the start of a heat. The maxim came down hard on the LF corner and continued bouncing off
the tires and landing right side up. Although all the bolt on stuff was torn loose, most
all of the major parts were in tack. The front axle was straight, the rear was ok, the
wing was flattened but the wing supports were not bent. The car looked like junk but most
of the damage was to the radius rods, torsion arms, heims, nerfs, a couple of wheels and
the frame.
It was not unexpected that the frame was damaged, what was
unexpected was the type of damage that I found. This frame shattered where it was
impacted. There are fourteen breaks in or near the weld between the front of the motor and
the torsion tubes. The connecting tubing is bowed to the right but not kinked. In all of
my experience, the weld should be stronger than the tubing and when frames are crashed,
the tubing bends until it kinks. In all the cases of crashed sprint car frames that I've
seen, the frame stays in tact and the impact causes bending and folding or it was
considered abnormal.
I'm not so concerned that the front came apart but what does that
say about what would happen if the hit had been on the the cage?
This is the J&J car we
got after the maxim disaster. A hard crash at Black Rock in 2006 impacted the RF corner
and bent up the front end. The J&J car did what was expected. Tubing
kinked and bent but stayed together retaining the strength of the structure. One
piece tore near the weld where the tubing was twisted and in tension. All other
damage was bends or kinks, no cracks or broken welds... The way it should be.
Tubing kinked, instead of breaking next to the weld.
From my experience, this type of failure is not
acceptable. Six of the 14 breaks were in the weld and the other eight were less than an
inch of the weld. The tubing all around the joints is not bent. In fact two pieces were
completely broken out at both ends and the pieces of tubing that were ripped out were not
even bent, even though they were being pulled or pushed in the middle of their length!
The x in front of the radiator was completely straight but both right side ends were
pulled out
of the right side upright. The lower left of the X is partly torn from the upright
but the upright
weld broke loose before the X was ripped all the way out.
The piece on the floor on the left is the lower frame rail from the right side motor mount
upright to the sway bar upright.
Here you see the LF front torsion tubes and the break in the weld at the end of the down
tube.
The left lower frame rail broke just below the weld to the torsion tube and the gusset
tube
broke at the down tube. The only thing that connected the front torsion tubes to the
rest of
the car was the right side downtube. All other connections were broken.
This is the end of the x-brace in front of the radiator where it pulled out of the right
upright.
This is the left side upright where the LF front motor plate connects and the LF radius
rod.
The piece of tubing is straight as new but the top is torn out and the bottom is broken at
the weld.
There is a little wrinkling in the upper diagonal where the diagonal was twisted.
Below...This is the broken weld on the left side motor mount tube from above.
This is where the X-brace in front of the radiator connects to the right side upright and
lower
frame rail.
This shows the only intact connection to the front torsion tubes, the lower frame rail
(triangular piece)
and the single piece is the sway bar upright. There is no dent in the tube (not hit
by the axle). It
broke out of the frame at the welds and was connected to the front axle by the aluminum
sway bar
and its aluminum heims. The sway bar was straight, threads were ok too, so it
looks like this tube
was yanked out when the axle hit on it's RF end and was pushed through the chassis.
The sway bar bolt is in the middle of this tube. The tube should have bent in the
middle if
the welds were at least as strong as the tube.
Sway bar upright to lower frame tube broken next to weld.
To me it looks like the tubing is brittle and weakened, at or near
the point of welding.
The Maxim chassis was 11 lbs lighter (6%) than an identical J&J that replaced it. I
think that lighter tubing can be acceptable when the tubing is being pulled straight in
tension during normal loading, but in a crash there are side loads. In any case, the
weld at least must be as strong as the tubing no matter what the wall thickness.
It seems logical to me that a tube that was being forced sideways to
its welded joint should either kink the joint INTO the other tube or bend and kink itself.
With kinked or bent tubing, there is still connected strength within the structure.
My concern is that the rest of the frame is no different from
the front end so...
--> A hit on the cage would likely have broken the cage in the same way <--
It would probably take a bigger hit to break the cage because there is more large diameter
support tubing, but if one piece breaks, it will free that area to move and pull on the
rest of the cage in leveraged and unexpected ways as impact forces are applied.
(Recently an ESS Maxim chassis car took a hit in the cage and the cage did break in
a number of places I am told. )
Additionally, once tubing breaks, the danger of injury is
increased as the disconnected tubing becomes a club or spear.
I don't know why my car broke up like it did, but there is something
different in this frame from any crashed frame I have seen before (maybe I haven't seen
enough crashed Maxims). Was this an aberration (defective frame) or do all Maxims fail
this way? The welding is always the first thing blamed and Maxim's welding on this car is
not pretty. The filler is piled on instead of having a smooth blended radius between
joined tubes.
I sent a couple of broken pieces to Mike at Maxim. Although
Maxim had the welds from the broken pieces inspected by an outside firm and the firm
determined that the unbroken welds were OK for penetration, undercut, etc.
They apparently didn't send them the broken pieces.
There is obviously something wrong with these welds. It
may be too much heat, too slow travel, too much filler, stingy argon gas flow..., you tell
me.
This is the glob style of welding on the Maxim Chassis. In the center of the photo
is the vertical
tube (right side) that holds the seat back mounting and goes to the top of the cage.
All of the welds on the car are build ups like this.
It almost looks like MIG instead of TIG welding.
Below is the same tube (left side) on the J&J car. The welds here have a blended
radius and
even beading. They are smooth and look like examples of proper welding that you find
in manuals on welding
and aircraft construction.
With Maxim's reported high turn over of welders, at best some will
be better than others, but in any case they will all be different. In Maxim's
defense, they say that all welders are certified and drug tested, but that doesn't address
all issues. It appears that any real investigation of their quality won't be done until
after some major catastrophe or high profile fatality occurs (hopefully that will
not happen).
Are there any structural engineers out there that that want to take
a crack at this, or have an idea about why this frame came apart like it did?. I contacted
Maxim about what I saw as a serious problem hoping they could learn something from it and
improve their product.
At first they seemed concerned, had a couple of tests tone by an
outside company and eventually got reports back that the welds and the tubing were
acceptable. Mike at Maxim had been very professional about working with me to find an
answer and I was hoping that the company would benefit from my destructive testing
But Maxim clearly did not want to admit to any fault.
And when I pressed Maxim for a reason why the frame broke at or near the welds and tubing
didn't bend or kink, I got this "up yours" response from the owner of Maxim.
From: RaceMaxim at aol.com
To: dave1w at a-znet.com
Sent: Monday, December 05, 2005 11:37 PM
Subject: Re: Frame breaks. FROM CHUCK MERRILL
Hello Dave: I think Mike has gone out Maxim's way to answer any legitimate questions you
have had about an older race car that probably was abused and welded on by God only knows
who and how many times. It may have even been clipped on the front end or somewhere else
by some back yard welder who thinks he is an expert. I appreciate your concern in this
matter but we have done all we can do to answer your questions. We have no reason to
pursue this matter any further. The roll cage did its job and you are here to tell about
it. Best Regards, Chuck Merrill
Unfortunately for Chuck, the frame was clearly a factory pure Maxim
from end to end as had been established with Mike at the outset. And
fortunately the rollcage was not impacted in the crash (wing posts were not even bent).
If they really cared about their product quality and improvement, they would have
had this frame shipped back to them for investigation. Maybe they've seen lots of
broken frames like this and they don't care or know any better.
So as I see it, this shattering looks to be a problem with something
in the Maxim fabrication process but they have no interest in finding out what happened
and how to prevent it. My crashed frame has been permanently retired. Maxim is
no longer on my Christmas list.
I'll keep the frame remains, and make a racing simulator someday,
but that's they only thing I'd use a Maxim for.
