User:Bogdanbojanic/sandbox

Turbine Fletched Arrows (Archery)
Turbine Fletched Arrows also known as Turbine Style Fletched Arrows is a style of fletching arrows for archery shooting with five or more Spin Vanes mounted in a continuous even pattern around the arrow shaft. Turbine Fletched Arrows are faster to spin-up to the ultimate rotation speed witch adds stability to the arrow flight and improves groupings.

Arrows are normally fletched with plastic vanes, rubber vanes or bird feather vanes. Fletching with more than four vanes has most benefits when used with thin plastic spin vanes. When fletching with rubber or bird feather the drag and weight increase will have negative effect on the arrow flight unless shoot by high poundage bow. The increase in drag and weight plus the sensitivity to rain and wind brings the usage to shorter distances and preferably indoor archery. The skin friction drag don't have any noticeable impact on the total drag in this particular case with Turbine Fletching. Performance increases when bow poundage is above 38lb and shooting distances at or below 20 yards (18 meters).

History
In time there has been debate about the ultimate numbers and size of vanes, this have been going on from the time the first arrow was made. In modern archery the most common is to fletch competition arrows with three or four vanes from 1.5 inch (40mm) length to 6 inches (12mm). Randy Walk, the former president of Hoyt Archery, was the first archer to publish pictures of his hunting setup where he was using 6 vanes on his arrows in the early 21st century. It havs been a believe for long time that when using lighter poundage bows and shooting on longer distances its beneficial to have less drag, therefore shorter and fewer vanes was to recommend. Lately this idea have been proven that in some cases fletching with more than 4 vanes even have the opposite effect. More than four fletched arrows can increase the grouping at longer distance and even decrease the hight on the parabolic trajectory. Studies by Miyazaki shows that the arrow point have similar effect on the arrows path. First time Turbine Fletched Vanes vas used in competition was during Swedish indoor nationals 2018, first time used at international level was 2020 during the Indoor World Series 2020-2021 by a Swedish Recurve Archer, Niki Bojanic Dennius and first time archer shooting with Turbine Fletching won an international competition was in February 2022 at the European indoor championship in Lasko, Slovenia.

This fletching style idea comes from the of the similarity of aircraft turbine engine intake, hence the name.

Fletching
Importance of precision tuning. When using three vanes at an arrow, one of them is called ”index vane” or ”cock feather”, this vane is supposed to face out from the bow while the other two will make a ”V” shape towards the rise of the bow to minimise the risks of hitting the bow, arrow rest, or the plunger. Shooting arrows like that will give bow clearance even if not 100% tuned bow/arows. When shooting turbine fletched arrows there is no margin for miss-tuned bow/arrows. The arrow is forced to pass clear of the bow for it to be effective and bring maximum precision. The spine have to be stiff enough to project the arrow away from the riser but still so soft that one flex orbit is finished just as the arrow clearers the riser of the bow. (Not applicable for Compound Bows)

As for fletching Turbine Stile Arrows the best performance is gained when a smal gap is left between the vanes. The airflow at the root of the vane is not compressed or disturbed while passing in the gap between the vanes, which will keep the airflow even and steady. If there is no gap between the vanes, the drag at the root of the arrow will increase and air will be forced to compress and move outwards from the arrow shaft. This smoothie airflow and enhances turbulence witch results in both drag increase and instability of the arrow, therefor Turbine Fletching without a gap between the vanes will counteract the benefits of Turbine Fletching. For the space between the vanes to be adekvat its therefore recommended to use thicker shafts. The thicker shafts have larger circumference than the competition style outdoor arrows and because of that the thicker shaft will have more space in between the vanes. Spin Vanes can be straight or helical in shape depending on the manufacturer, they can be fletched parallel or offset its up to each and every archers preferences. What is important is that all vanes have the exact same angle and that they are absolutely parallel to each other.