For Your Viewing Pleasure
- Thread starter gsbaker
- Start date
Racer Chris
New member
Gregg,
On the Production Racing Forum David Finch has made what amounts to a veiled accusation that the Hans video is intentionally skewed by your company. I don't believe David's theory but to dispel the air of partiality he is working to create could you answer a couple of questions for me?
Did Isaac pay for the HANS test? Were the arm restraints set up differently with any intent to change the test results? Did Delphi knowingly conduct the tests with different parameters? Any other info you have to close this issue would be helpful.
TIA,
Chris Foley
On the Production Racing Forum David Finch has made what amounts to a veiled accusation that the Hans video is intentionally skewed by your company. I don't believe David's theory but to dispel the air of partiality he is working to create could you answer a couple of questions for me?
Did Isaac pay for the HANS test? Were the arm restraints set up differently with any intent to change the test results? Did Delphi knowingly conduct the tests with different parameters? Any other info you have to close this issue would be helpful.
TIA,
Chris Foley
Chris,
We figured this would happen. The solution is very simple: Have SFI make public the video of the same test. Or HANS for that matter. If they have one video of the belts not coming off, I'm certain the world, including their customers and sales reps, would love to see it.
We contracted with Delphi to perform the 38.1 test. We pay for all of our testing. We'd be more than happy to use someone else's money, however, so feel free to send some. Neither HANS nor SFI would disclose the data, so that was the only way to get it.
Talk is cheap. If some turkey thinks the results are rigged, let them prove it by getting different results with the same test. Of course, if that happens one must call into question the test protocol, but that's another issue.
erlrich
Super Moderator
No so veiled, actually. Here is a link to that discussion for anyone interested. Prod Forum
David's comments do raise a few questons, though, which the answers to could put some of his accusations to bed: were the two tests run on the same day; who requested/paid for the tests; and were there any special testing requirements other than "run the SFI test"?
Also Gregg, I have to ask, from purely a marketing standpoint (keeping in mind I am an accountant and know almost nothing about marketing
), why would you not go ahead and hit the Isaac in a frontal impact, just to be able to say you did it, and it passed with flying colors, and we have now passed all of the 38.1 performance requirements, blah, blah, blah, and more importantly to silence the critics who like to use this as a point of criticism? I realized the test is expensive, and probably unnecessary, but wouldn't the marketing value almost offset the cost?****EDIT: sorry Gregg, you and I were typing at the same time, you obviously type faster (I want a rematch!). Please disregard those questions you've already answered above
****Earl,
If we were to conduct the straight fontal impact--which would result in an upper neck tension value of between 1,700 and 2,100 Newtons of force--skeptics would claim we rigged it. The only value to conducting that test is if SFI drops section 2.5, so why should we bother?
It is a very simple matter to prove us wrong. Between HANS, SFI and others there must be a dozen plus videos of the HANS device on that same sled running SFI 38.1 offset. So post one.
Now, if someone wants to make a little wager...
If we were to conduct the straight fontal impact--which would result in an upper neck tension value of between 1,700 and 2,100 Newtons of force--skeptics would claim we rigged it. The only value to conducting that test is if SFI drops section 2.5, so why should we bother?
It is a very simple matter to prove us wrong. Between HANS, SFI and others there must be a dozen plus videos of the HANS device on that same sled running SFI 38.1 offset. So post one.
Now, if someone wants to make a little wager...
Matt Rowe
New member
I'll also put forth the same question I asked on the production forums. If the motion of the driver's arm can cause such an obvious issue with the Hans device where should a driver put his hands in the event of a crash. (and don't say take them off the wheel, we all already know that one) Seriously though if the simple act of having the drivers wrist held near his thigh causes the hans to slide from under the belts that doesn't seem like a robust design. Later models may have improved on that, but when did the change occur and how much testing has been done to verify the fixes works in a wide variety of situations?
And Gregg, it's great that you "know" the frontal impact numbers will be low, but we would all still like to see the proof.
And Gregg, it's great that you "know" the frontal impact numbers will be low, but we would all still like to see the proof.
dave parker
New member
Words to live by.
cheers
"dangerous" dave parker
I'm not sure there ever was a fix. That lateral load is severe, so I'm not sure the changes are enough to make a difference at 70Gs. That change came out last fall, IIRC.
Sure, that would be nice for the record, but we can't get very excited about it. Doing something you know you can do is like kissing your sister.
Now, if you want to hit an Isaac system head on, the place to do it is on a 100G sled in Michigan. Let's run some round numbers:
Say the Isaac intermediate does 2,000N head on at 70Gs. Extrapolating that to 100Gs (not always accurate, but there is no other way to go) gets us ~2,850N, which works. The fun part though is hitting the $295 Link model on that sled. It may not make the 3200N limit, but it looks good for the 4,000N limit Mike mentioned. If it doesn't work as presently configured we can switch the webbing to Kevlar. A <$500 product good for 100Gs is worth going after.
If Mike can produce evidence that a crash dummy anywhere, on any sled, experienced more upper neck tension in a direct frontal impact than it did in an offset impact, we'll test it direct frontal. But that doesn't happen. That's why the normal SFI limits are lower for frontals. Sure, they will let you get away with the higher offset number, but only after failing the frontal test twice.
Bill Miller
New member
To me, David Finch's comments are tantamount to slander (or is it libel?, one is written, the other is spoken). I've asked him to substantiate his claim, or retract it.
Slander is spoken; libel is written.
We occasionally see this. It has never come to it, but we have had counsel prepped to move. Amazing how many self-annointed experts there are out there.
Hey, if I'm an electrician, I'm not going to tell the plumber he's wrong.
A wager usually works.
Please stop making these false statements, :angry: or are you claiming to meet a performance specification that you don't comprehend and have not run all of the tests for?
The frontal limit is 4,000N, same as the offset.
At least two frontal pulls are required, but only one offset.
If neither of the first two frontal pulls exceeds 3,200N, then a third frontal pull is not required. Since multiple frontal pulls are required but only one offset pull, the SFI must consider the frontal pull to be significant.
Mike, don't pretend to know what I comprehend, please. It's very simple: Can you provide any evidence that frontal loads are higher than offset loads--for any dummy on any test sled, anywhere?
Edit: On reflection, taking an absolutist approach like this does nothing to further the discussion. One may be able to find an example of frontal loads being higher than offset loads, but that's not the point. The point is that there is no scientific evidence to suggest that direct frontal loads are ~45% greater than offset, the value at which the Isaac system would fail to pass the SFI frontal test, i.e. 3,200N.
That's your theory (off set loads always higher), fine.
My theory says you still need to do a frontal test.
Everyone's entitled to their theories and opinions,but we shouldn't misrepresent the facts.
You have misquoted SFI 38.1 as proof of your theory, twice in this thread. After being corrected, and yourself admitting the error, you mis-state it again.
My theory says you still need to do a frontal test.
Everyone's entitled to their theories and opinions,but we shouldn't misrepresent the facts.
You have misquoted SFI 38.1 as proof of your theory, twice in this thread. After being corrected, and yourself admitting the error, you mis-state it again.
erlrich
Super Moderator
Ok, in the interest of fairness, here are the pertinent sections of the spec, verbatim - you guys decide:
5.1.3 PROCEDURE
B. The test sled shall be propelled to produce the racing acceleration pulse (Figures 2A and 2
at a nominal 68G peak, 70 KPH (43.5 mph) velocity change. A minimum of two (2) frontal tests and one (1) 30 degree right frontal test will be required. To be considered valid tests, the results of each of the frontal tests must be 3,200 N or less. If the frontal results fail to meet the above requirement, then a third frontal test will be required and none of the three values shall be above the maximum requirements per paragraph 6.1.1 The 30 degree right frontal test must meet the requirements of paragraph 6.1.1.
6.1.1 IMPACT PERFORMANCE FOR EACH TEST (procured from Hybrid III test device).
Maximum Upper Neck Tension 4,000 N (899 lbs.)
Maximum Upper Neck Compression 4,000 N (899 lbs.)
Maximum Value of NIJ 1.0
To my feeble brain this means SFI would prefer to see two frontal tests at less than 3,200 N, but if you can't meet those requiremenets we'll let you get by with 4,000 N if you run a third test and all three are under 4,000 N. That also implies to me that loads between 3,200 - 4,000 N are considered to be in the marginal range, which tells me that I would want nothing to do with a system that couldn't get below 3,200. JMHO of course.
5.1.3 PROCEDURE
B. The test sled shall be propelled to produce the racing acceleration pulse (Figures 2A and 2
at a nominal 68G peak, 70 KPH (43.5 mph) velocity change. A minimum of two (2) frontal tests and one (1) 30 degree right frontal test will be required. To be considered valid tests, the results of each of the frontal tests must be 3,200 N or less. If the frontal results fail to meet the above requirement, then a third frontal test will be required and none of the three values shall be above the maximum requirements per paragraph 6.1.1 The 30 degree right frontal test must meet the requirements of paragraph 6.1.1.6.1.1 IMPACT PERFORMANCE FOR EACH TEST (procured from Hybrid III test device).
Maximum Upper Neck Tension 4,000 N (899 lbs.)
Maximum Upper Neck Compression 4,000 N (899 lbs.)
Maximum Value of NIJ 1.0
To my feeble brain this means SFI would prefer to see two frontal tests at less than 3,200 N, but if you can't meet those requiremenets we'll let you get by with 4,000 N if you run a third test and all three are under 4,000 N. That also implies to me that loads between 3,200 - 4,000 N are considered to be in the marginal range, which tells me that I would want nothing to do with a system that couldn't get below 3,200. JMHO of course.
lateapex911
Super Moderator
Who actually wrote the SFI requirements? Who do they (or him/her) work for? What was the arrangement that produced the results we just read?
Bill Miller
New member
Originally posted by gsbaker@Dec 21 2005, 07:55 PM
Slander is spoken; libel is written.
We occasionally see this. It has never come to it, but we have had counsel prepped to move. Amazing how many self-annointed experts there are out there.
Hey, if I'm an electrician, I'm not going to tell the plumber he's wrong.
A wager usually works.
[snapback]68901[/snapback]
Thanks Gregg, couldn't remember which was which. I noticed that Mr. Finch has stated that he will not retract his comments. Merry Christmas!
