"Just got back from the USUSA meet. Boy, that was a blast. Met a guy from your area who demonstrated your tow release - I'm impressed! Please send me a couple."

Ron Kenney
Region 6 Instructor

The light weight, low cost, sure fire, place anywhere,
Tow Release for Hang Gliders and Paragliders

———————
STATIC TOW SETUP
———————

Youtube video of yours truly launching at Bong Park, WI

Aug 2012: Video of Miller Stroud foot-launching his ATOS
using 2 Linknife Releases with an over/under bridle.

Hewett bridle and Linknife

Launch style discussed uses the 2:1 Hewett Center-of-Mass Bridle
See other static line photos here.

The idea behind any release is to be easy to set up, and not activate until it's needed (not a moment sooner). When it is needed - at the top of tow or in an emergency - it has to work the first time, every time. The Linknife does that quite efficiently and works by cutting the weaklink, simple as that.

See this page for setting up a 2:1 bridle.

MAIN RELEASE PLACEMENT
As a MAIN release, place the Linknife between the bridle and towline. Pass the weaklink loop through the loop on the towline end. Pass the two loop ends of the weaklink through the slots in the Linknife and into the 1/4" rapid link on the bridle. Tie the release pull string to your harness shoulder loops or straps, in easy reach by either hand.

Note in the illustration below how the lower part of the bridle is routed UNDER the control bar. Route it above just once and you'll quickly see why the word UNDER is in all caps. If such a thing should happen, release at your first opportunity, if not sooner, before you get pulled down.

AFTER (normal) RELEASING
1. First and foremost, FLY THE GLIDER!
2. Release the main bridle from the waist shackle.
3. FLY THE GLIDER!
4. Gradually roll up the bridle and stow in the harness.

If you land with the bridle dragging behind you, it's possible that it could snag on something. As much of a possibility as that is, in more than 20 years of static line towing, I have yet to see it happen during a landing approach. Still, it's good style to fly clean.

BACKUP PLACEMENT
Place alternate backup - for emergency use only - directly on the bridle at the keel or on the upper bridle line in front of the pilot. Backups like this are not really recommended for Hewett 2:1 bridles as pilot injury is possible when the bridle whips through the waist shackle. Your hook knife is the best option for a release failure (not that the Linknife is going to fail or anything, but no release in 100% foolproof. You might set it up wrong... who knows?).

Static Line Towing with Hewett Bridle (illustration)

Optionally, add 6 inches of small shrink tubing (diagram below) to the pull string, snug against the Linknife, to prevent the Linknife from twisting around the weaklink. You can also customize the setup by mounting a small dog leash reel to your harness for the pull string. (Make sure you lock it with some slack line out before launching!)

WEAKLINKS
A 4-strand weaklink will set up easily between the towline and the bridle. My personal favorite for a weaklink is 130-pound braided dacron kite string, tied with a grapevine knot. I weight 170, those heavier will probably want to use something like 150# line.

Starting with 18-20 inches of string, this gives me a large enough loop to work while wearing gloves. Insert the first loop through the towline, then pass the 2 end loops through the Linknife above the O-ring as shown below. Place both loop ends in the rapid link. Don't forget to close the rapid link. See the Linknife Operation (takes 1 minute to load)

Placing shrink tubing on release pull string (Hewett Bridle)

An alternate PITCH LIMITER line can be attached to the glider's nose. See Opinion Page for more information on this concept.

Linknife Tow Release photo

COSTS:

Linknife — $20 each + shipping.
Club/dealer discounts available.

Bridles (aero or static), include Linknife,
rapid links and setup instructions

Convenient Ordering:

Note: Using PayPal is very simple. You do NOT need to be a member of PayPal to make a purchase. You may use a credit card like any other system. If your order is to be shipped outside the US, if you'd like a customized autograph, or prefer to pay by check, please contact me.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
LINKNIFE - USA
=================================
US orders (1-9) @ $20.00 each + $1.50 shipping.

-----------------------------------------------------
Quantity orders (10+) @ $15.00 each + $5.00 shipping per lot of 10.
Use PayPal's "Send Money" option or drop me a note and we'll work it out.
THANKS.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
LINKNIFE - CANADA
=================================
US orders (1-9) @ $20.00 each + $7.00 shipping.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Other orders – please write with your specifics for quantity
and shipping method. Use PayPal's "Send Money" feature for
the total amount. (Recently sent 10 to Turkey.)

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
BRIDLES – Static Line Towing and Aerotowing
=================================
All bridles are made from red 900-pound heat set and stretched braided dacron with woven and hand-sewn loops in the ends. Measurements are what I've found to work; if you have a different need, gimme a call.

Static Line Tow Bridle - aka: 2:1 Hewett Center of Mass Bridle
SEE BRIDLE PAGE or STATIC LINE PAGE

For foot launch towing with a static or payout winch. Kit contents include:
(A) Main line is 22' loop-to-loop.
(B) Waist line is 3' which allows tying an overhand loop knot to keep the shackle, self-locking carabiner or whatever you choose, from sliding side-to-side.
(C) Keel line is a 6' length of plain bridle material without finished ends, for you to tie however works best for your glider.
(D) Four (4) 1/4" rapid links
(E) Linknife Release with extra O-ring.

COST: $70.00 + $5.00 mailing to US addresses.

Kit does not include the static tow waist bridle release mechanism (such as sailboat shackle) or release pull string as there are too many optional ways of setting this up. Custom bridles are available; please call or write with your specifications.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Aerotow Bridle - 1:1 V-line
SEE AEROTOW PAGE

For aerotowing via foot or dolly launch. Kit contents include:
(A) Main V-line is about 8' loop-to-loop.
(B) Chest bridle is 3' long and attaches to one end loop of the main bridle with a larkshead knot or, if the release is placed at the keel, a secondary/backup release can be placed here.
(C) Keel line is a 6' length of plain bridle material without finished ends, for you to tie however works best for your glider.
(D) Two (2) 1/4" rapid links for at the bridle apex and attaching the main bridle at the keel,
(E) Two (2) 1/8" rapid links for attaching the chest bridle to the harness shoulder loops
(F) Linknife Release with extra O-ring.

COST: $55.00 + $5.00 mailing to US addresses.

Kit does not include the release pull string as there are too many optional ways of setting this up. Custom bridles are available; please call or write and let's see what can be done.

Use PayPal's "Send Money" option for easiest payment.

-----------------------------------------------------
or send check to:
Birren Design Company
502 Shadywood Lane
Elk Grove, Illinois 60007
P: 847/640-0171
E: Email

DISCLAIMER: As with all aviation endeavors, your choice and use of equipment is totally up to you. It is assumed you are an experienced HG or PG tow pilot who is intimately familiar with the style of towing you will be doing. As such, YOU ASSUME ALL RISK AND LIABILITY in the use of the Linknife, as well as all other parts, functions and personnel involved in the towing and flight operations. If you do not have experience in towing, please contact an instructor for expert training. Trying to learn on your own can, and probably will, result in your injury and even death. Many pilots have paid the ultimate price so we may now tow as safely as never before possible. Please learn from their lessons.

Back to the top

Birren Design Company | Site Map

——————— STATIC TOW SETUP ———————

Convenient Ordering:

———————
STATIC TOW SETUP
———————