Performance Designs, Inc. 1300 E. International Speedway Blvd DeLand, FL 32724 USA Tel: +1 (386) 738 2224 Fax: +1 (386) 734 8297 www.performancedesigns.com
VE/VC BK-TOG Extension Synopsis This document focuses on:
Why you would extend the brake to toggle (BK-TOG) Who should/should not extend the BK-TOG How to choose the right setting for you How to get your BK-TOG extended
Background Changes in gear preference and flying styles have resulted in many jumpers requesting longer BK-TOGs. Standard riser length is considered to be around 21” or 22” and adequate for most jumpers. However, some jumpers and especially those within the swooping community prefer longer risers for a number of reasons. Some are increasing the length by only a couple of inches, but some go with risers as long as 25” or 26”. Certain flying styles and techniques in swooping require a greater range of movement in the harness, and this may require longer BK-TOG to prevent tail deflection during certain maneuvers. For example, a canopy pilot who pulls the front risers down to their chest will need to extend the length of their control lines, because the toggles remain in their hands and they are pulling them down as well. If your tail is being ‘engaged’ while doing a front riser turn, the wing is not performing to the maximum efficiency…in other words, it is like giving gas and brakes at the same time. Who should extend the BK-TOG We solicited the advice of the best canopy pilots out there. Jay Moledzki sums it up well: “Jumpers with longer arms and/or longer risers and pilots looking for increased freedom of movement in the harness, in relation to the controls.” Another PDFT member and Flight-1 founder points out how it is a personal preference: “I lengthen my brakes because I have longer risers and I like a deep control range – both brakes and front risers. For any canopy, I like the bottom of my control range to be at about ¾ arm extension. This means that the start of my control input happens very deep in the toggle stroke, sometimes as low as the shoulders. It’s a personal preference.” - Shannon Pilcher
Who should NOT extend the BK-TOG If you do not have a clear understanding of what factors will change by extending the BK-TOG, you should not be doing so. If you extend them because you have super long risers, or prefer a deep control range, the tradeoff is that you have to pull down farther on the toggles to get a response from the canopy. This can be dangerous if you have a low turn, need to stab out, and are not familiar with the point at which input gives response. Another scenario where you should not extend the BK-TOG is if you are not consistently using the same gear. For example, if you frequently borrow someone else’s Velocity (VE) and your BK-TOG are set to +3” or +6”, when you get on a VE that is set shorter you will find the stall point quicker. If you have built up a muscle memory for where the stall point is, you may find yourself stalling the canopy with shorter control lines on a landing. How to choose the appropriate setting If you have established that you do prefer a longer BK-TOG, the best way to go about extending them is incrementally. You should not be adding more than 3” at a time, and should be doing many jumps with the new setting before adding more length. If/when you decide to increase the length of your risers, consider where you want your control range to be in relation to that change. If you are happy with your current set up, change your BKTOG length in relation to how much you lengthen your risers. For example: If you are lengthening your risers by 2”, lengthen your BK-TOG to the next longest setting (3” longer). How to get them extended There are a couple of ways you can get your BK-TOG extended. If you are having your canopy relined, this would be a good opportunity to request extending the BK-TOG. For field replacements, whether it is the full line set or just the lower control system (LSTs), have your rigger consult the line trim charts. It is important to make sure you know precisely what length your current BK-TOG is before ordering LSTs or a new line set. http://www.performancedesigns.com/docs/linetrims/VE_075-120LT.pdf http://www.performancedesigns.com/docs/linetrims/VC-071-111-Line-Trim-Chart.pdf http://www.performancedesigns.com/docs/linetrims/Measure-Line-Trim.pdf ***CAUTION: Do not remove the bartack to let out the finger trapped line. There must be 2” of finger trapped line (1.5” past the bartack) to maintain structural integrity.***
MAN-029 Rev. A
VE/VC BK-TOG Extension Synopsis
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Actual Brake to Toggle (BK-TOG) lengths with optional extended BK-TOG Stock VE Canopies / sizes VC 71 VC / VE 75 VC / VE 79 VC / VE 84 VC / VE 90 VC / VE 96 VC / VE 103 VC / VE 111 VE 120
Regular n/a 13 1/8 13 1/2 14 14 3/8 14 7/8 15 1/2 16 16 3/4
Stock VC (VE + 3") Long 15 1/8 16 1/8 16 1/2 17 17 3/8 17 7/8 18 1/2 19 19 3/4
VC + 3" (VE + 6") X-Long 18 1/8 19 1/8 19 1/2 20 20 3/8 20 7/8 21 1/2 22 22 3/4
VC + 6" (VE + 9") XX-Long 21 1/8 22 1/8 22 1/2 23 23 3/8 23 7/8 24 1/2 25 25 3/4
Alternate guide rings PD is aware that some pilots use a guide ring attached to the SLink, as opposed to the guide ring on the riser that is standard on virtually all risers. We recognize some people may prefer this setup, but want to call attention to a couple of things. First, if you are using a system like this, do not attach this ring to the same SLink that attaches the lines to the riser. Use a separate tab or SLink to hold this ring. Using the same SLink that attaches lines to the riser will cause premature wear to your suspension lines, brake lines and SLink. Second, we have continually seen excessive slider grommet and RDS ring damage due to the metal to metal contact of this guide ring and the grommets/RDS rings. This is something to be aware of, and should be taken into consideration if you are thinking of utilizing this set up.
MAN-029 Rev. A
VE/VC BK-TOG Extension Synopsis
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