Well, Happy Birthday to me! I shall be/am/was one year old on 23 October! Don’t let me stop you if you want to send an expensive present!
OK, it may not exactly be my genuine first birthday (I wish!), but it is the uniBoffin’s. It’s just a year since that particular Creature arose from the Big Boss’s Black Lagoon of dubious nom-de-plumes so that yours truly could avoid the personal reprisals that might otherwise have resulted from burdening the darting public with unasked-for dissertations on static margins and moments of inertia.
As it so happens, this particular dissertation is the 20th, which seems like a suitable score on which to settle down comfortably and look back nostalgically at what else we’ve talked about. We’ve met exemplary dart players like Nigel the Novice, Little Len and his mate Lofty, Neil Armstrong and Phil Taylor and sought wisdom from characters as diverse as Pythagoras, Blackadder, Shakespeare and Groucho Marx. We’ve unsuccessfully played darts on the moon and successfully solved a Sherlock Holmes mystery. All this plus the joy of some fairly painful title puns along the way (sorry about those!).
With such a wealth of variety in a simple series of blogs on flight dynamics, it has occurred to me that newer or less frequent visitors to these pages - or just those with a less-than-perfect memory - might get a bit lost when I refer to something I talked about several months ago. So, with apologies to those who have come here expecting some new and exciting aerodynamic revelation (promise I’ll try and think of one for next time!) herewith a handy reference guide to those from the year just past. What could be more useful? (Don’t answer that!)
Pushing on regardless of any chocolate fireguard comments just provoked, after my first “Not Rocket Science?” blog established the credentials of my nascent persona and of my Frankensteinian offspring uniLab (now, incidentally, updated with the 2009 range), the second “Difference between Chalk and CGs” explained the concepts of aerodynamic lift and stability and introduced Centre of Gravity as an important factor. “A Margin for Error” discussed how the CG combined with the Centre of Pressure to determine that infamous static margin and “Yaw Choice” then described the incidence, pitch and yaw terms for flight angle and settled on the last as the most convenient. It also described the crucial theoretical basis for a dart having a characteristic yaw wavelength and casually dropped that dreaded moments of inertia phrase for “A Matter of Some Moment” to pick up and “MI2” to juggle with.
“Sigmata” explained how all the theory had found application in Sigma Pro and Sigma One darts and “Are You a Pro or a One?” covered the difference between the two. “Sigma to the Power of One” dealt with how Phil Taylor had surprised us all by throwing his old darts away and running off with a set of Sigma Pros and “Cycle to Work” implicitly explained why this might have been something to do with their carefully-designed yaw wavelength.
Just to make sure everyone didn’t get too carried away with all the aerodynamic jargon, “The Good, the Bad and the Ungainly” then looked at how the aerodynamic niceties of a dart must still come second to the bio-mechanical interface with, and the attitude of, the player who’s throwing it. Notwithstanding that, “The Adventure of the Three-Quarter” and “Delta Force” showed how tailoring the aerodynamics to the skill level of the player can still help good scoring and hence just why Sigma Pros are called Pros and use delta flights and side-load shafts. In a somewhat similar vein, “Lab Oratory” further examined the theory behind that tailoring and explained the basis of the recommendations uniLab makes on which type of darts might suit which type of player.
Moving on to topics new, “The Spin Doctor” discussed the issue of spinning a dart, a subject on which I received so many comments that most of “Factor Fiction?” was devoted to answering them, although I still found some space to drop a few hints about the then forthcoming release of Sigma 950s – hints on which “Sigma Squared” put some flesh.
Nearly up-to-date, in “Dragged Out of Bed” I almost dismissed aerodynamic drag as a puny force not worthy of licking lift’s boots, only to see them literally join forces in “Yawn Drag” – so titled because it may be my most tedious essay to date (although I was disagreed with on this point in the subsequent comments. Thanks for that, Paul – it’s just a shame I seem to have tested your enthusiasm even more this time!)
And so, with this, that makes 20. But, now we’ve settled that particular score, one question may occur to the more cynical amongst you. Does number 20’s shameless use of the old how-do-we–still-make-an-episode-of-a-sitcom-when-the-star’s-in-rehab trick of re-running past highlights mean that I’ve finally run out of ideas? Is the has-been rock god so devoid of new material that he’s had to release that death-knell of a Greatest Hits album? Can the uniBoffin even make his second birthday?
Well, rest assured the good (or should it be bad?) news is that I can easily go on well into even greater senility explaining ever-more abstruse aspects of flight dynamics to interested dart players. But that assumes I’ll think there still are any out there! So, with that proviso in mind, thanks to all those who took the trouble to submit comments over the past year and herewith the Q&As for this landmark anniversary edition!
Q&As
Jon and Warren (from two uniBlogs ago) and Caleb and Larry on Nose Flats, etc
Yes, guys, as I said in “Sigma Squared”, higher percentage tungsten is more brittle, which can cause problems with nose cracking and is one reason why some Unicorn darts have larger nose flats than may be ideal from a flight damage perspective. On this latter topic, as Larry guesses, “rat-chewed” trailing edges shouldn’t affect things too much, Caleb, but may be a sign that the whole flight has been bent, which would be more significant. If players themselves want to take the risk of chamfering the nose a little more after purchase to help avoid this, fair enough, but for a reputable manufacturer like Unicorn to do so would, as I said, risk an unacceptably high rate of returns and quality control issues. (By the way, Larry, thanks for the Sigma plaudits!)
Paul and Spin and Number of Fins
Explanations on some of the issues you raise, Paul, are in my “The Spin Doctor” blog, which asks “is spinning a dart a good thing?” and answers “Well, yes-ish”, but maybe I’ll look at the question again sometime. As for flights with more than 4 panels, you’ve caught on to the comments I made in the Q&As to “Sigma Squared” as to why it isn’t just the practicality of fitting them into a shaft that’s a drawback - the aerodynamic interference between panels and reduced aspect ratio means that more panels have more total length of trailing edge to block follow-on darts. But, if we ignore that issue for a moment and your possible solution of perforated rip-off flights (as you say, potentially good for sales, but possibly not destined to be popular with the majority of players – especially during a world-wide recession!) the topic you raise about the optimal number of panels is an interesting one (well, fairly!).
I remember many years ago deciding the theoretical answer was probably 5, but you are right that 4 is the most common for missiles (often for reasons of launcher compatibility), although 6 or more are sometimes used. The patent you mention concerning the advantages of odd numbers of fins over even in fact relates to reducing stability variation with roll rather than increasing stability in itself. It was filed by guys who are respected US professionals in the field and I would hesitate to cast doubts on the validity of their supporting data, but I must admit I remain to be convinced!
Bob and Gold Sigma 950s.
No plans for these from my side, Bob. Somehow it would seem a bit frivolously unscientific of me just to bring them out in a different colour - although what Unicorn’s marketing department might decide to do is another matter entirely!