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Linknife Home Page See how it works Static Tow Setup Aerotow Setup Payout Towing Setup Testimonials Pitch Limiter NASA X-38 RHGPA Home Site Map Birren Design Home

free-lance designer, in business since 1975 with 16 national design awards


"In my opinion, the LINKNIFE is exceptionally brilliant! It is the best release I know about."

Donnell Hewett,
Towing pioneer, author of Skyting Criteria, inventor of the concept of towline tension sensing and designer of the Hewett Center-of-Mass bridle.













"NOTHING works better than the Linknife."

Jeff Sinason
Former Region 6 Director


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

Ne postoji
za otkaz otkacivaca

Vuca je odlican nacin da se zapocne let paragliderom ili zmajem. Za neke pilote to je i jedini nacin. Nitko si ne zeli pokvariti leti ili se uznemiravati zbog problema s otkvacivanjem.

——————————NAA logo

March 18, 2006 - At the Fall USHPA BOD Meeting, the Linknife received the National Aeronautic Association Safety Award. I can't tell you how honored I am for this official recognition. What an incredible thing!!!

Click here to see an animation of how it works


Linknife je otkacivac koji odbacuje vucno uze od
pilota presjecanjem clanka slabe sile.

Moze sluziti kao glavni ili kao rezervni sistem otkvacivanja. Postavlja se vrlo jednostavno na svako mjesto u sistemu na kojemu moze biti potreban (vucno uze, osigurac, uzde).

Glavne prednosti Linknife-a su:

  • Vucne sile prolaze kroz Linknife. To znaci da je uvijek potrebna ista sila (oko 2 kg) za otkacivanje, bez obzira kolika je sila na vucno uze. Kod drugih otkvacivaca obicno je potrebna veca sila otkacivanja sto je vucna sila veca.

  • Vrlo mala masa. Kod jedva 7 grama nema puno mase koja pilotu moze prouzrokovati problem usljed naglog vracanja otkvacivaca zbog pucanja vucnog uzeta ili clanka slabe sile.

  • Male dimenzije. Linknife je dugacak svega 60mm. Zbog malih dimenzija lako ga je smjestiti na moguce polozaje i manje smeta kada (vise) nije potreban.

  • Bez metala na vucnom uzetu. Vjerojatnost ozljede ljudi i ostecivanja stvari na zemlji je manja, ukljucujuci i operatera prilikom namatanja uzeta na zemlji. Znatno je smanjena mogucnost zapinjanja prilikom vracanja uzeta.

  • Oblikovan za sigurnost. Od velicine otvora koja onemogucuje ozljedjivanje prstiju do vrlo jednostavne izmjene gumenog prstena, sve na Linknife-u izradjeno je za sigurnost. Naravno, na pilotu ostaje da ga sigurno upotrebljava.

  • Fleksibilan pri ugradnji. Jednostavan za upotrebu u svakoj vrsti vuce... kod letjelice, pilota, vucnog vozila... siguran je i pouzdan. Koristi se za sve vrste vucne uzadi.

  • Niska cijena. Pored svojih prednosti Linknife je jedan od najjeftinijih otkvacivaca.

A 1/4" (6mm) thick steel ring, or rapid link as shown above, is needed to back up the Linknife in Static Line Towing or other methods where the Linknife requires an angular pull. This prevents the Linknife from cutting the bridle. Smaller links can get caught in the slots. For Aerotowing, where the main release is (optionally placed) on the bridle at the keel, the rapid link is not always necessary as the direction of pull is perpendicular to the line.

Bez obzira na vrstu vuce - aerozaprega, staticna, payout, stacionarna - Linknife je odgovarajuci otkvacivac. Ne postoji mogucnost da slucajno otpadne, pa je tu uvijek kada je potreban.

X-38 photo

NASA (Nacionalna Aeronauticka i Svemirska Administracija, SAD) nabavila je 14 Linknife otkvacivaca za upotrebu na X-38, svemirskom brodu za spasavanje iz svemirskih stanica. Na svakom brodu koriste 4 za odbacivanje inicijalnog kocionog padobrana. Video Link

Linknife Tow Release photo


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 or prefer to pay by check, please contact me.

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US orders (1-9) @ $20.00 each + $1.50 shipping.

paypal button

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.
PayPal button

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US orders (1-9) @ $20.00 each + $7.00 shipping.

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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.)

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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

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.

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Aerotow Bridle - 1:1 V-line

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:
Peter Birren
1657 W Farwell Ave, #3C
Chicago IL 60626
P: 773-654-3950
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.

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Linknife Home | Static Line | Aerotowing | Payout/Platform
Pitch Limiter | Testimonials | Demonstration

Reel Pilots Home | Members | Criteria | Driver SOP
Flying Sites | Links | Airshow | Site Opening Primer | Photos
Static Line Basics | Static Towing Parts | Hewett Bridle Basics
Lockouts | Launch Post | Payout Primer

Birren Design Company | Site Map


Award Plaque


Page last update: June 14, 2017
This entire site and the Linknife™ Towing Release © 2000-2008 Birren Design Company