Cronk works


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Cronk works

Dave Cronk in the 2008 documentary Big Blue Sky by Bill Liscomb
Dave Cronk in the 2008 documentary Big Blue Sky by Bill Liscomb

In 1971, a new kind of aviation was beginning, or rather re-emerging after it was forgotten when the Wright brothers successfully added engines and propellers to their biplane glider nearly 70 years before. The new technology of hang gliding found a number of its early leaders on and around the beaches of Los Angeles county, southern California. One of those leaders is David Cronk, who in 1975 additionally became the first ever world hang gliding champion.

Cronkite

I NEVER intended to get this high above the ground.

— Dave Cronk (e-mail correspondence, 2020)

Dave Cronk in his Cronkite 2 at Redondo Beach Esplanade in about 1970. Photo by Tony Abbott.
The new activity of hang gliding gets a green light. Photo by Dave Cronk’s old friend Tony Abbott.

The Cronkite 2 of about 1970, here flying at Redondo Beach, featured a ‘parallel bars’ style hang cage.

Dave Cronk flying the Cronkite in 1971
Dave flying the Cronkite in 1971 or 1972

Spoilers at the wing tips, operated by an ingenious system of shoulder-pressed levers, provide good turning control.

— According to Paul Wahl writing in Popular Science, June 1972


Dave Cronk testing a Cronkite hang glider destined for Switzerland at Torrance Beach
Dave Cronk testing a Cronkite destined for Jean Francois Didisheim in Switzerland at Torrance Beach, California

By this stage, a triangular control frame replaced the hang cage.

Cronkite at Torrey Pines, San Diego, California, in 1973 or 1974
Cronkite at Torrey Pines, San Diego, California, in 1973 or 1974
Cronkite V specifications published in Ground Skimmer, December 1975
Cronkite V specifications published in Ground Skimmer, December 1975

See also the short low-resolution digitized film by Carl Boenish on YouTube for Dave Cronk flying this wing at Torrey Pines, set to a 16th century English folk ballad instrumental (under External links).

Chuck Slusarczyk’s Falcon was a bird-like wing similar in concept to the Cronkite. See the page Chuck’s Glider Supplies of Ohio.


Dave Cronk flying his Cronkite at Torrance Beach in about 1971. Photo by W.A. Allen.
Art based on a photo by W.A. Allen of Dave Cronk flying his Cronkite at Torrance Beach in about 1971
Reverse of postcard Dave Cronk flying his Cronkite at Torrance Beach in about 1971
Reverse of postcard Dave Cronk flying his Cronkite at Torrance Beach, California, in about 1971

Dave Cronk 500 ft over Torrance Beach in about 1973. Photo by Carl Boenish.
Dave Cronk 500 ft over Torrance Beach in about 1973. Photo by Carl Boenish.

Torrance Beach, about 1973 or so. Carl Boenish set up a keel mounted camera, and we got this great shot. Jack Schroeder and Danny Bostwick flank both sides on a beautiful, post-storm day.

— Dave Cronk (e-mail correspondence, 2020)

Dave Cronk, Bob Lovejoy, and the Quicksilver

Dave Cronk launches from the bluffs at Torrance Beach in the prototype Quicksilver as its designer, Bob Lovejoy, moves clear in about 1972. Photo by George Uveges.
Dave Cronk launches from the bluffs at Torrance Beach in the prototype Quicksilver as its designer, Bob Lovejoy, moves clear in about 1972. Photo by George Uveges.

This was Quicksilver prototype #1. Bob and I had only flown this glider off of Playa Del Rey CA (Dockweiller). I went first, and found myself dumbfound (and terrified) by quickly rising above the ridge and gaining perhaps 100 feet. This glider had a very marginal structure, and used clothesline pulleys and string for controls. After this flight, I took it back to the shop and immediately began improvements.

— Dave Cronk


Dave de-rigs an early Quicksilver in 1973 at Playa Del Rey.  Photo by W.A. Allen.
Dave de-rigs an early Quicksilver in 1973 at Playa Del Rey. Photo by W.A. Allen.
Quicksilver in the Bill Liscomb documentary 'Big Blue Sky'
Quicksilver in the Bill Liscomb documentary Big Blue Sky at 35 minutes 22 seconds

Quicksilver #2, Playa Del Rey, CA, about 1972-73. Based on our prototype (Bob Lovejoy and myself) I added two feet of span, bringing it to 32 feet. This still incorporated the laminated wood battens (or ribs) that flattened when damp. I also upgraded the rudder with a rigid trailing edge, stiffened up the empennage system with double wires, and generally upgraded everything that was sketchy in the original.

Bob Lovejoy did not stay involved in hang-gliding after his first design effort. Although he was a partner in Eipper-Formance, he never got back into the sport, or the hang glider design world.

Bob was a brilliant toy designer at Mattel Toys, and had a great reputation there.

— Dave Cronk

For more about Bob Lovejoy, see Project Quicksilver in Hang gliding before 1973.


Dave Cronk flying the Quicksilver third prototype at Torrance in 1972 or 1973
Dave Cronk flying the Quicksilver third prototype at Torrance in 1972 or 1973

I had increased wing spar size, added a second lift-cable bay, increased cable diameter, upgraded the rudder control system components, and generally brought things up to a point where I felt confident flying well-above the ground.

— Dave Cronk


Art based on a photo by Bettina Gray of Dave Cronk and Bill Liscomb
Art based on a photo by Bettina Gray of hang glider designer Dave Cronk and pioneering pilot Bill Liscomb

In later life Bill Liscomb created the film documentary Big Blue Sky, in which David Cronk is interviewed about the early days of hang glider development and the flying at Torrance Beach.

Quicksilver B specifications published in Ground Skimmer, December 1975
Quicksilver B specifications published in Ground Skimmer, December 1975
Quicksilver C specifications published in Ground Skimmer, December 1975
Quicksilver C specifications published in Ground Skimmer, December 1975
Dave Cronk lands his Quicksilver C. Photo by W.A. Allen.
Dave Cronk lands his Quicksilver C. Photo by W.A. Allen.
Quicksilver D to H specifications published in Ground Skimmer, December 1975
Quicksilver D to H specifications published in Ground Skimmer, December 1975

I had the luxury of designing and flying a wide range of Quicksilver variations. Sometimes I would design for a particular site, person, or event.

— Dave Cronk


Dave Cronk's last Quicksilver design, 1977
Dave Cronk’s last Quicksilver design, 1977

This was my final Quicksilver glider design. By this time (about 1977) flexible wing glider performance had surpassed the best Quicksilvers. I flew them mostly for soaring in smooth lift sites, like Torrey Pines.

— Dave Cronk


Powered ultralight by Air-Tech of Louisiana
Powered ultralight by Air-Tech of Louisiana

It’s hard to believe that this monster, a modern Quicksilver derivative, is fully based on the original 1971 prototype. 1200 lbs, 100 hp.

— Dave Cronk

Variometer

Dave Cronk's variometer of 1973
Dave Cronk’s variometer of 1973

A vario system I set up in the early 70s. This is the earliest use of a vario in a modern hang glider that I am aware of. I used it at the Annie Green Springs prelim test meet practice session.

— Dave Cronk

Annie Green Springs (a wine label of the commercial sponsor) was the U.S. national hang gliding championships of 1973. See the Variometers page for more.

Cronksail

Cronksail in about 1973
Cronksail in about 1973

Dubbed the “Cronksail” by Joe Faust. Inspired by seeing Richard Millers’ seminal Conduit Condor. This image shows very early preliminary tip-rudders that were subsequently refined. Prototype #1 was literally run over by a Greyhound bus on the 405 freeway when the glider came off the racks on the way to its first test-flight. Good knot tying skills are important.

— Dave Cronk

Cronksail specifications published in Ground Skimmer, December 1975
Cronksail specifications published in Ground Skimmer, December 1975

Cronksail at 'the Domes' on Palos Verdes with the Mitchell brothers at left
Cronksail at ‘the Domes’ on Palos Verdes with the Mitchell brothers at left

The Mitchell brothers were well known Seagull (of Santa Monica) fliers.

Cronksail at 'the Domes' on Palos Verdes
Cronksail at ‘the Domes’ on Palos Verdes

That must be Santa Catalina island on the horizon. See also the Domes, Palos Verdes related topics menu.

Eipper Cumulus

The first ever official world hang gliding championship was held at Kössen, Austria, in 1975. Dave Cronk won it in an Eipper Cumulus 4.

Dave Cronk becomes world hang gliding champion in Austria flying an Eipper Cumulus 4 in 1975
Dave Cronk becomes world hang gliding champion in Austria flying an Eipper Cumulus 4 in 1975

Cumulus 4. This design was the first in the industry (I think) to use high strength 2024 T3, thin-wall tubing.

— Dave Cronk

There are two video clips of Dave landing this wing at this event under External links.


Eipper Cumulus 5s balloon drop in about 1976. Photo by Mike Deegan.
Eipper Cumulus 5s balloon drop in about 1976. Photo by Mike Deegan.

World largest hot air balloon at the time c1976 or so. All Cumulus 5s and 5-Bs. The “B” added tip battens and increased tip chord. A very popular line of gliders.

That’s Dave Cronk in his Mendij-painted Cumulus VB at left (partly obscuring another wing). See also the Hang glider sail art related topics menu.

Art based on a photo by Bettina Gray of Dave Cronk landing an Eipper Cumulus with sail painted by Medij in 1975
Art based on a photo by Bettina Gray of Dave Cronk landing an Eipper Cumulus with sail painted by Medij in 1975
Dave Cronk's Eipper Cumulus 5 with sail painted by Mendij
Dave Cronk’s Eipper Cumulus 5 with sail painted by Mendij
Joe Greblo with Dave Cronk's Mendij Cumulus 5 at Crestline in 2010
Veteran instructor Joe Greblo with Dave Cronk’s Mendij Cumulus 5 at Crestline in 2010

Joe flew this glider off the low hill in Crestline this day: The glider’s first flight since 1978 or so. Mendij painted this for me. It took roughly 2 months of painstaking tapping and rubbing in oil paint, both sides.

— Dave Cronk (via e-mail, March 2020)

See Our Vintage Fly-In under External links later on this page for video of Joe Greblo flying it in 2010.

Cumulus V specifications published in Ground Skimmer, December 1975
Cumulus V specifications published in Ground Skimmer, December 1975

Dave Cronk and an Eipper Cumulus 10 at the Air and Space museum, Dulles, Washington DC
Dave Cronk and an Eipper Cumulus 10 at the Smithsonian Air and Space museum, Washington DC

This was the last of the Cumis, in a long line of successful gliders.

Related

Early powered ultralights

Eipper-Formance of Torrance, California

Torrance Beach

External links

Air-Tech Inc. Ultralight Aircraft

Austria World Hang Gliding Championship 1975 AP Archive video on YouTube starting at 12 minutes 3 seconds: Dave lands the Cumulus 4 and is then interviewed

Austria World Hang Gliding Championship 1975 AP Archive video on YouTube starting at 14 minutes 29 seconds: Again Dave lands the Cumulus 4…

Austria World Hang Gliding Championship 1975 AP Archive video on YouTube starting at 15 minutes 31 seconds: Dave interviewed about the result

Hanggliding Worldcup 1975 (Drachenflug WM 75 Kössen in Tirol) digitized film ‘Free as a Bird’ by Julian Grant on YouTube starting at 42 minutes 23 seconds (narration in German)

Hang Gliding – Hackler’s Fly-in, 1976 digitized film on YouTube starting at 1 minute 13 seconds; Eipper Cumulus 5Bs and Quicksilvers mostly

Our Vintage Fly-In by Ken Westfall starting at 4 minutes 9 seconds for Joe Greblo and Mike Quinn flying the Mendij Cumulus VB at Andy Jackson Air Park in 2010

Playground in the Sky, 1977, by Carl Boenish on YouTube (low resolution) starting at 25 minutes 19 seconds for Dave Cronk flying his Cronkite (followed by Volmer Jensen in the VJ-23, then Taras in the Icarus 2 and Icarus 5…)

Big Blue Sky video external links

These are links to Big Blue Sky — The history of modern hang gliding – the first extreme sport!, 2008, documentary by Bill Liscomb on YouTube:

Response to Cronk works

rochellecronk1 says:
March 26, 2020 at 22:26
Most talented man ever!! Wish I could have seen this all in person!

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