I promised a chrono report on my recently finished laminated flatbow. Here it is...
Note: This is a non-objective report, based on the experience of one person, me, and should be taken accordingly...
Chronicle of the Chronograph
I got a shock this morning… I finally decided not to do any constructive work, but rather to buckle down and set up the chronograph, which has been sitting in its box all week. I don’t know why I thought this was going to be complicated. Once I opened the box and took a look, it’s incredibly simple. Ten minutes later I had it mounted on a camera tripod and was busy learning stuff… both good and bad.
I had one previous experience with chrono’ing bows. Someone brought a nice chrono setup to Moses Lake and I had two Hills checked. Both were 48@25… one with carbon and one without. They averaged 160 and 159 respectively. No real advantage shown for the carbon. Now, this setup used a very fine system of mechanical drawing and a mechanical release. Based on this, I tended to think that at least at that weight, I was shooting about 160… mentally rounding off. The problem with this was/is that I have a bad under-drawing problem and I don’t use a mechanical release. Ah, the ways in which we delude ourselves!
After I had to drop down in weight, so that at present I’m shooting basically from 30 to 35 pounds, I figured I was probably shooting about 150 at optimum. Bear in mind that I’m shooting this low poundage, and with a 25” draw. I believe most of the chrono info you see in “official” bow tests is at 28” and with mechanical release. That makes sense from a consistency of comparison standpoint.
So, based on all that, I kind of thought that maybe my new flatbow, as really shot by me, might have me at 140, since I didn’t expect it to perform up to the level of custom bows, like my Hills.
What did the chrono teach me? Well, first, it’s a very daunting instrument. It is totally objective. It doesn’t allow you to pump any sunshine into the equation… it just tells it like it is. It quickly tells you the difference between a proper full draw and a draw that isn’t. It’s a wonderful training tool in that respect… regularly practicing by shooting through it should keep you on your toes and thinking about that draw. Fairly quickly, I found myself drawing to full anchor much more consistently than is my norm. That’s part of the good news. As simple as it is to use, I really recommend having one of these around.
More good news… my new flatbow shoots every bit as fast as any of my Hills, and, in fact, as fast as any of my simple, straight longbows. This really surprised and, of course, pleased me.
However, every coin has two sides. The actual speed at which I’m shooting these bows was, to me, shockingly low… a consistent 130 fps. Short drawing drops me down to 120 or even less. Really concentrating on getting a long, full draw got me a few shots just over 140… my new magic number and something I’m going to work on.
Of course, having done this much work, more was needed… after all, I have more bows than just straight longbows. In all, I chrono’ed over 20 bows. I didn’t work very scientifically, didn’t keep notes or anything like that. I just wanted to see what differences I could note and if my purely subjective previous shooting experiences had any validity.
Most of the bows tested were in the range of 33 to 38 pounds. A couple were lighter and a couple heavier. The same arrows were used… 1616 aluminums weighing 307 gr., or just under 8.8 gr. per pound at 35#.
From straight traditional longbows I moved on to R/D longbows, including Pronghorn, Sentman, Belcher, and Berry. What I found, with a couple of exceptions that will be noted, is that by and large, R/D longbows averaged about 10 to 12 fps better than the straight Hill style longbows, letting me shoot consistently in the range of high 130’s to mid-140’s.
Next was to try the recurves, which included a variety of Bears, Toelke, Martin Hi-Speed and Trad Tech Titan. I really expected great things here, because my “shooting impressions” were that I shot these considerably better. Not so… the recurves consistently shot in the same range as the R/D bows… low to mid 140’s. I did seem to be more consistent with the recurves, especially those with a little lower draw. I really expected a noticeable difference with the Titan, but again, not so.
A major discovery, in terms of my shooting, was that within the fairly limited range of bow weights tested, draw weight seemed to make little difference. I shot a couple of recurves that were notably lower weight, down around 28 to 30 pounds, and got basically the same readings. I think this was probably due to their being very easy on the draw, and thus easier to achieve consistent full draw. More on this later…
Now… exceptions. Two bows showed up out of the class average… real barnburners by my standards. These two bows showed consistent readings over 150. The bows were a Belcher Lady Longhorn, 33@26 and the J. D. Berry Viper, 33@25. I’ve actually had the Belcher for awhile and somehow it just got sidetracked and I hadn’t shot it much. Guess I’d better hang onto it!
Based on this experience, what can I comment on about the differences in bows? First, as I have always found, the big difference for me is not as much in differences caused by draw weight, as it is in the feel of the draw. Recurves almost universally seem much smoother and easier to draw, weight for weight. Shooting a bow that is easier to draw makes me a better shot. The recurves, especially at the lighter end of my range, are simply more pleasant. The R/Ds would be next. The straight, traditional longbows are a stiffer draw.
Conclusions… Well, I’m disappointed that I’m not shooting as fast an arrow as I had tried to convince myself I was, but I’m terribly pleased that I came up with a bow that, weight for weight, shoots as fast as my Hills, which are kind of my standard for a traditional bow. I guess I have to accept the limitations of my short arms and short draw. As for the draw on my flatbow, while it’s stiff, it isn’t really much stiffer than my Hill Longbowman’s Choice.
Overall, my future work in bow making will be aimed at learning to build a bow with a smoother, easier draw for whatever weight. I’ll also surely try for a bit lighter weight. I’d like to achieve a flatbow within my weight range that as smooth a draw as my Bears. I also learned that speed is not the main thing to worry about. Shoot a weight you’re comfortable with and match an arrow to that shooting weight and you’ll get as much speed as you’re going to, within your shooting form and the reality of finger release. I know from experience while I was so week this past spring that I can shoot as low as 23# with proper arrows and still be satisfied with my results on a 3D course. If you have a short draw, you’re not going to get as high speed as advertised for a given bow. Live with it and adjust.
Dick in Seattle
Topic: Chronicle of the Chronograph (Read 221 times)
