From: NASA Blogs
Posted: Friday, February 20, 2009
Next week I am on the agenda of the NASA Project Management Challenge training event to give a talk on "The Power of Accepting Criticism". This was a talk that I planned to give last year, but a conflict caused me to back out at the last minute. So up until last evening, I was feeling pretty good about having the speech ready, it was written a year ago, with only minor updates to polish it up.
Now I think I'm going to tear that speech up and write a new one. Same topic, new info. All because of an email exchange I had last evening.
Here is what I got - not as a comment to my blog, but as a direct email -- as I was waiting for my plane to take me home:
Your most recent blog post, "Just put chicken wire in it!"
has prompted me to take the time to give you some feedback in regard to an older post, Tripping the Boundary Layer - Part 1, http://blogs.nasa.gov/cm/blog/waynehalesblog.blog/posts/post_1232662169255.html.
In this older post you appear to have made a very large simplification/generalization of the issue of boundary layer transition as it applies to scramjets.
"When the boundary layer over the wings or in the engine is laminar, there is low drag and low heating; and when the boundary layer is turbulent, drag and heating increase dramatically. All boundary layers can be "tripped" or transition from laminar to turbulent flow.
In some of these experimental aircraft the engines [called SCRAM jets for Supersonic Combustion Ram jet engines] have only operated for a fraction of a second or a very few seconds. Why? Because the designers do not know how to cool them; they don't understand when or whether the boundary layer inside the engine is turbulent or laminar."
First, both Hyper-X flights (Mach7 and 10,
had the fuel flowing to the engine for approximately 10 seconds. See http://hapb-www.larc.nasa.gov/Public/Ops/X-43A-2/Flight2/mission_profile.gif.
Can we agree this is more than "a very few?" and that in real terms steady-state operation was obtained? Technical people should be precise in the terms they use to communicate among themselves and with others. Second, are you aware that both the Mach 7 and 10 flights specifically incorporated boundary layers trips near the leading edge of the forebody to ensure that the boundary layer entering the engine was turbulent, for a very specific technical reason?
for a reference.
So, sir if you are going to take to task those individuals who out of the blue just post wacko ideas to a NASA web site blindly soliciting input, I think a high level technical person such as yourself should look in the mirror with respect to the apparently uninformed opinion you have posted about the Hyper-X scramjet ground and flight tests in disservice to myself and everyone else who contributed to this program and in fact the boundary layer transition data it has provided for both the tripped under surface and the untripped upper surface over a very wide range of conditions over total boost, test and descent trajectory for both flights.
This is not to take anything away from the need/desire to get more transition data from the shuttle. I just think it is a poor choice to denigrate the Hyper-X program as you did, in order to provide additional out of context justification.
On my blackberry I thumbed out a quick reply explaining my blog and felt pretty good that the note would assuage the email author.
I was wrong. Here was his response to my flimsy explanation:
I'm sorry, but you have just confirmed to me what is wrong with this agency and that it's time to look elsewhere. If you can't be technically correct and still make your case, you have gone over to the dark side of management or even worse PAO.
So you just make stuff up to make your point. Heck of a way to promote technical excellence in the agency!
I had three and a half hours of electronic isolation on the plane last night to ponder this exchange. Here is my conclusion:
I did a tremendous disservice to those folks who have worked diligently in the area of hypersonic flight. A number of teams have launched test vehicles: Australian, Russian, others. The most impressive was the NASA Hyper-X test program which had two very successful tests about five years ago. Summarizing these efforts in two or three superficial sentences clearly demeans their achievements. I would offer a humble apology to those who labor in this field, particularly all of those who on the Hyper-X project.
In review, it is clear that I have become lax in my technical explanations. It is the height of laziness to brush off a subject because it is hard to explain to the lay public and therefore not to make the effort. So I pledge to renew my efforts to be more technically precise in these posts while still attempting to make some of these subjects clear to the non-expert reader.
Second, I promise, no more whiny blogs about postings on the internet. The nature of some of the discourse on the internet is simply a fact of twenty first century life which I am not going to be able to change and therefore it is unworthy of my complaint.
Finally, no more putting down the public because they are not experts in the space field. My job here should be education, not criticism.
Well, enough for one day. I have a speech to revise.
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