Bungeelista Update Report, April 5, 2006

Just an update on where we are with the up coming bungee bow experiment (which I will now call the bungeelista experiment since bungee bows don?t actually have ?bows? as such). Robert Gascard and I have built six more of the bungeelistas so we will have a total of seven at Festival. Three will be used by lights and four by heavy archers (who will also be participating in the heavy archer half gauntlet experiment). The bolts are made of 20 cm lengths of 25 mm UPVC electrical conduit (the same material used here for ballista bolts). The heads are comprised of a 18 mm (ID - internal diameter) rubber chair tip that sits inside the tube and a 25 mm (ID) tip that sits over that and outside the tube. The internal chair tip is forced some distance into the tube but cannot go all the way in, this prevents the tube from coming into contact with, and possibly punching through, the outer chair tip. Both internal and external chair tips are taped on with electrical tape. The bolts have ?nocks? made of two 30mm by 15mm strips of leather taped to the end of the tube so half the leather projects over the end. We recently fired about 10 rounds of 90 bolts at a foam covered wooden target on two different occasions for a total of 1,800 repetitions (2 x 10 x 90). Bolts were inspected after each firing and four were found to be defective due to the tips becoming loose. I?ll point out that the heads hadn?t fallen off but inspection revealed that the tape had broken enough to allow them to be easily pulled off. I figure that this is acceptable as the number of failures was low and all were noted when inspected prior to firing (i.e. no heads actually fell off because of being fired). The draw weight of the seven bungeelistas was measured with a spring balance and found to all be within 32 lbs and 36 lbs at a draw of around 22 inches. Using the inch/pound formula described in the US missile rules, this corresponds to an inch/pound rating of 704 lbs to 792 lbs. The US rules allow for crossbows firing bolts with 1 1/4 inch heads to have a rating of 1000 inch/pounds. This puts our bungeelistas at 70% to 80% of the maximum (the external rubber tips have an outside diameter that is almost exactly 1 1/4 inches). We fired four shots into the back of Amadeus of Amesbury who was wearing only a light gambeson. He described the hits as having more ?thump? but less ?sting? than regular arrows. William de Shatterton used one of the bungeelistas as a light in Rowany?s most recent war practice. He noted the comments of two of his targets. Ulric considered a hit to his hand to be ?OK?. Blaeney commented that the hit he recieved was ?solid?. My own impression is that the bungeelistas at about 800 inch/pounds are a little underpowered and that 1000 inch/pounds would be a reasonable limit. Unfortunately, the combination of the bungee cord we are using and the size of the bows means that the cords elastic limit is reached at or around 35 lbs i.e. we cannot get a greater draw weight with the cord we are using. Although I believe the bungeelistas to be a little underpowered I do think people will be able to register hits well enough that proceeding with the experiment in the current configuration will be a useful exercise. If all goes well I propose that we run the experiment again at Spring War with the bungeelistas set at 1000 inch/pounds (which will involve getting heavier cord and potentially shortening the draw). To put the draw weight in perspective, the bungeelista I used at Spring War two years ago had a draw rating of 1100 inch pounds and there were no complaints. On the subject of accuracy, the bungeelistas seem quite accurate at ranges of 15 meters or less but accuracy drops of significantly at 20 to 25 meters. The maximum range is around 50 meters but hitting anything at that range is down to luck. One thing of note is that people who have never shot a bow before do surprisingly well, 3 out of 4 hits on a man sized target at 15 meters with little or no practice. The bolts generally fly quite straight even though we are not using any fletching. About 1 in 15 or 20 shots will wobble a little but fly straight enough that there is no danger of being struck by the shaft or end. We also tried clout shooting and all the bolts turned over and landed rubber end down. That?s about it. I just figured the Marshalling community would appreciate the heads up. Corin