Repeatability and the San Diego Wind Tunnel

A few years back, I wrote this sucker:

http://www.biketechreview.com/aerodynamics/uncertainty.htm

whoa, that's probably the third time I've used partial differentiation in a setting outside of academia!!! :-)

To be honest, my experience as a consumer product development engineer in the bike biz (2+ years) and the golf biz (coming up on 10 years now... holy cow!) is much more caveman based than what doing partial differentiation might suggest.

Granted, the tools/toys I get to play with in the golf biz these days are a couple steps above the beer cans and bits of string I got to use in the labs I had at my disposal while in the bike biz... ;-) ...but, still, I think that even with the fancy tools I get to use these days, I find myself relying on my caveman instincts when it comes to judging "goodness" of data that so many of the high tech gadgets can spit out.

Y'know, folks will have to assess for me how well their methodology and instrumentation they have used can repeat a given measurement/setup condition within a day and across days before it gets my attention. For example, with a pedaling rider in the tunnel, I have seen things (axial force) repeat to within less than 10 grams...but I've also seen things not repeat so well. Over the years, and more than a thousand runs with pedaling riders, I've grown to know how much I can trust what the tunnel is telling me...and that knowledge drives the way I choose to test.

The same kind of familiarity with repeatability is helpful when placing "equipment only" wind tunnel test #'s into context.

Not sure where I'm going with all of this, other than, I don't think folks think about experimental uncertainty enough - especially when it comes to doing field tests with a power meter. "Subjective validation" of these data might kick in if you wind up getting the answer you were more or less looking for:



Anyway, speaking of repeatability, I was checking out some additional repeat data I have on a specialized trispoke (the same one linked to in the partial derivative link above) today. I've tested this exact wheel/tire combination in a couple tunnels (texas a&m and lswt.com). I've tested the trispoke in the san diego wind tunnel eight times since 2005 (yeah, that would be over a four year time period) at a beta=0 flow condition.

What was the standard deviation of the multiple runs over that 4 year period for the exact same wheel/tire setup? 3.8 grams of axial force at 30mph. That seems pretty good to me. What do you think? What can the other tunnels do over that same four year time period in terms of "equipment only" repeatability?

So, yeah, that std deviation tells me about how well I can trust the data coming out of the facility here in San Diego over time. My caveman instincts are comfortable with these data out of San Diego! :-)

da Vinci Got it Right! (and so did the guys behind Mercury, Gemini & Apollo)

Back in probably 1998 or so, I was fortunate enough to walk the halls of the Louvre in Paris, France. I’m not a huge art historian, though; I would characterize myself as one who enjoys looking at art – more for the possibility of finding something I “like” more than anything else. I mean, I can’t talk intelligently about art (I did get an “A” in art history at Washington State University – but getting an “A” in “art” in inland Washington State ain’t sayin’ much, is it!), nor do I really care to, to be honest…but, when I see something I like, well, it strikes an emotional chord within me. It resonates a bit, and I can appreciate that. I reckon I become attached to that kind of feeling and really pay attention when those sort of feelings come a bubblin’n up.

I can’t really explain what I like in art – maybe it’s like “porn” – y’know, I can tell you when I see it! D’oh! Hey, this is a family show! ;-)

I like this (yeah, film is art, eh?) :



And this:

the persistence of time

and not so much this

…but hey…that’s one of Leonardo daVinci’s most famous pieces!?! Well, yeah, maybe I’m tainted by the context within which I experienced the painting of the Mona Lisa. Y’see, in the Louvre, everyone goes to see the Mona Lisa (or so it seems)…and thus, the context in which I experienced that painting was not appealing to me…and, that’s probably what I hang onto when thinking about the “mona lisa”. For me, that painting is attached to “lots of people acting like crazed tourists”. I’m not so into that, and so, yeah - that kind of deal sticks with me…

I much preferred the setting of the Borghese Museum in Rome:

Fewer people by design/coincidence (hey, y’know context matters when it comes to art!)…crazy detailed sculpture and some fine art at the Borghese in a much more intimate setting…

But really, when it comes to sitting on a bike…I gotta agree with da Vinci:



…seems he got things about right when sketching out his bike design concepts, what, 500 years ago or so? :-)

I see a little bit of a blend of old-school European seat tube angles and “new-school” (is there anything new school in bikes?) softride in that sucker, pictured above, eh?

The way I experienced the da Vinci exhibit here at the San Diego Air and Space Museum was pretty neat. We basically had the whole exhibit to ourselves for the better part of an hour. Most of the other folks had probably already seen these da Vinci replicas, but for Selene and me, it was a first. So, we enjoyed the intimacy of the moment offered to us and dove into the true “da Vinci Experience”.

The guy was pretty amazing – he was so far ahead of his time mechanically, it’s not even funny. Who’d a thunk it? I mean, he had ball bearings figured out in the late 1400’s:



And his breadth of ideas and innovation, when experiencing it in the museum exhibit, was a bit bewildering to be honest.

The real reason, though, we were there at the museum, was to pay tribute to Kennedy’s vision, in a way:



…to pay tribute to some of the greatest heroes America has known – y’know, they were before the steroids in baseball/football or EPO in cycling era! ;-)

The guys of this era put forth a bold goal of landing a man on the moon before the end of the 60’s. They took the courage, inspiration, and hope proffered up by Kennedy…and got the job done. The men we saw…the men we met...the men we shook hands with:




…last weekend were the men that stepped up and met those great expectations to be pioneers, leaders, heroes. They were the men that tackled the challenges that they had no concept of, but met those challenges with hope, vigor and unwavering perseverance and faith.

Undoubtedly, there were sacrifices and setbacks along the way to the moon
(Apollo 1) that weighed heavily on them and the United States:



…but, just as Kennedy prophesized in 1962 in the speech linked above:

“We choose to go to the moon. We choose to go to the moon in this decade and do the other things… Not because they are easy…but, because they are hard…Because that goal will serve to organize and measure the best of our energies and skills…Because that challenge is one that we are willing to accept…One we are unwilling to postpone…And one we intend to win.”

It is important to note that the Apollo 1 disaster, and all those learning opportunities it presented…ultimately begat the Apollo 7 triumph.
It’s even possible to imagine that without the Apollo 1 fire, we might not have taken Gene Kranz’s words in response to that incident to heart:

“Spaceflight will never tolerate carelessness, incapacity, and neglect. Somewhere, somehow, we screwed up. It could have been in design, build, or test. Whatever it was, we should have caught it.
…
“From this day forward, Flight Control will be known by two words: 'Tough' and 'Competent.' Tough means we are forever accountable for what we do or what we fail to do. We will never again compromise our responsibilities. Every time we walk into Mission Control we will know what we stand for. Competent means we will never take anything for granted. We will never be found short in our knowledge and in our skills.”

So, with Apollo 1, and Apollo 7, and Gene Kranz’s sage words, we finally were able to raise the level of our game and realize the Apollo 11 achievement:



…and I think it is really important to note that none of the Apollo missions could have been accomplished without the progression of the Mercury and Gemini projects.

All of these missions were intertwined and linked. Each one building upon the other in lockstep.

Hey, y’know the guy with the texas twang barkin’ out

“60 seconds” and “30 seconds” and “Roger, twang…tranquility. We copy you on the ground. We got a bunch of guys about to turn blue. We’re breathing again. Thanks a lot.”

…in the closing seconds of that video about Apollo 11 linked above? Well that gentleman was seated at our table last weekend on the deck of the USS Midway (the aircraft carrier that featured heavily in the Vietnam war).



Brigadier General Charles Duke is his name, and he’s a real American hero, I reckon. We were honored to shake his hand, and to hear his stories and perspective that evening. Did you know that he was in his mid 30’s during that Apollo 11 mission where he was CapComm (capsule communicator) in Houston? And, at that age, he was one of the senior members of the whole deal?



Can you imagine being given the responsibility to make the call on whether or not to abort a landing attempt during Apollo 11 in your mid 30’s with less than 60 seconds to go until touchdown?

Y’know…that 60 second call that Mr. Duke was barkin’ out in the video above was really a “60 seconds of fuel remaining” call…and not a 60 seconds to touch down call…y’see, Neal Armstrong was lightin’ up the thrusters, floatin’ across the surface of the moon trying to find a safe place to touch down after the initial spot didn’t look so hot. When Charles Duke said “30 seconds”, that meant there was less than 30 seconds of fuel left…And they still had to get off the moon! Talk about pressure, responsibility, faith…no wonder there wasn’t much breathing going on amongst mission control in Houston.

Luckily, the eagle landed safely, and the rest was history so to speak…

Yeah, Neal Armstrong was the first man on the moon...And the guy who was guiding him down in the audio above, Charles Duke – wound up being the lunar lander pilot during Apollo 16 and, ultimately, the tenth man to set foot on the surface of the moon. Pretty cool, eh?

Lots of cool stories were told during the festivities at the museum on Friday night (the evening before our Midway experience)…but probably the one story that sticks out the most to me was told by Glynn Lunney. He was second shift flight controller while Gene Kranz was the first shift director of flight control in Houston during the Apollo 13 mission, and he featured heavily during events of the Apollo 13 mission:



Lunney’s thoughts on “trust”, that he shared with us that evening, between the government, NASA, and his bosses (you have to remember, that Lunney and his crew were all in their mid to early 30’s/late 20’s at the time doing something that had never been done before…) were pretty inspirational.



Here’s how I remember the Apollo 13 anecdote that he shared with the attendees…
…as he took over from Gene Kranz a little less than an hour after the oxygen tanks “blew”, he and his team were delegated to find a solution to one of the tasks essential to getting the crew back home – I want to remember that it was the powering up sequence of the lunar module after it had been powered down. He and his team had explored every possible avenue for a significant period…they left no stone unturned…finally, he and his team had created a “book” (an operational manual detailing a checklist to proceed through) on the sequence and were prepared to present it to the big wigs of NASA.

Lunney recalled for us, that he, as a 32-ish year old was sitting in front of a panel of his elders going through what they proposed to do…when he was completed with the briefing, he recalled…the room sat in silence until one of his bosses began to speak…Lunney told us that, inside, he was fully prepared to hear this senior administrator start picking apart his team’s plan with a bunch of questions and whatnot…instead, there was only one statement from one of his “superiors”:

“What can we do to support you and your team?”

As an engineer, let me tell you that I think that’s pretty crazy to see that type of behavior in such a high-risk, high-pressure situation very often. It’s a remarkable story. The point, as I saw it, was that you just don’t see that kind of thing these days in industry, or the government…But really, the Lunney story is just a great story about trust.

That senior administrator knew his limitations in the situation, delegated responsibility to the subject matter experts, and then let go…the administration had forced their team to choose a path. It seems to me, as if when we are forced to make a choice on our own, that decision making process is pretty powerful – it is the best way to learn, I feel, since one is forced to consider and weigh the consequences and potential outcomes. And ultimately accept responsibility for the path taken…I can see how this type of decision-making process is ultimately the job of any triathlon/bike racing “coach” in the industry today. The job of these coaches should be to coach us into making better decisions for ourselves…If your bike racing coach doesn’t have that as one of his priorities in the relationship with you, well then, I reckon I’d suggest finding a new “coach”. There are plenty of good coaches out there.

I feel that being encouraged to make our own decisions and choices when faced with new challenges is also the demarking line between being “on board” and being “fully engaged”. Anyone can be “on board”, but being “fully engaged” is where it’s at, I reckon.

There’s a lesson for the wannabe “managers” of the business world, and “coaches” of the bike racing world in that Lunney anecdote, eh?

All in all, a great weekend – one definitely for the memory banks. It was inspirational. It made me think a bit more deeply about how I choose to go about things. The experience re-assured my sense that, given the opportunity, people will ultimately step up to a challenge and prove that they have the right stuff to get the job done…

Peace,
-k