F1A development history

It occurred to me recently that there is no timeline showing the major developments in the fine art of flying F1A gliders, so this page represents an attempt to fill this gap. I started to fly Free Flight in the mid 1960s, so I've shamelessly picked brains to find out what happened earlier. Corrections and suggestions for additions are most welcome and should be sent to Martin Gregorie.

Before Nordic A/2

In a private communication John O'Donnell has confirmed that auto-rudders and, indeed, offset tow hooks have a long history:

The auto-rudder goes back a long way. It is described in Warring's book Model Gliders (published 1942) with the basic idea originating in 1939. This book features RHW's Aeolus design, complete with auto-rudder. Offset hooks came later. They are described in Mick Farthing's article on lightweight gliders in the January 1948 Aeromodeller, and shown on the accompanying plan of his 1947 model.

I also asked John how advanced the arts of towing and finding lift on the line were in the early to mid 1950s. Here's his answer:

I, for one, knew about towing for lift and could detect it on tow at least as far back as 1953. At the A/2 Trials that year I was in contention for a Team place after two flights. A final max (five minutes) was all I needed. My approach in these circumstances was to fly without D/T: risky but worth it. The technique worked twice, since I broke a line and called for an attempt before seeing the model go away in lift. The retake with my second model went to plan, but was not seen for the full five minutes. This was before binocular timing. I did get both models back eventually via the public.

If you think my approach was extreme, let me quote that of Geoff Byrd, who topped the Trials. He didn't even attempt to retrieve his first model, saying that it tires you out at the beginning of the day! He went downwind after his second flight, and searched until he found one or other of the models. Then he came back for the final flight. I was/am not the only person with a ruthless approach to contests. The models are tools, not an end in themselves. Few people accept this! I learnt a lot that day.

I saw Lindner win in 1955, not by lengthy towing, but by watching a non contest flight made by someone else at one side of the launch area. Lindner then flew elsewhere! This caused much controversy at the time.

An e-mail from Dave Dent adds the following:

Zoom launching - I remember the Loughboro' College A/2 team using this technique during 1953 and they had probably used it during the previous year. It was during one of the eliminators in 1953 at Hemswell - when the wind was westerly and blowing up the scarp face adjacent to the field. I remember them towing right up to the edge of the field and zooming off the towline and also gaining some assistance from the slope updraught. This greatly impressed me at the time although I didn't take advantage of the technique until many years later. This could be the same contest that John O'D refers to in his notes.

The timeline

1951 Event definition The initial F1A class was defined with 100m tow line and a fuselage minimum cross section rule. Areas and weights were the same then as now. Auto-rudders and offset hooks were already in use. Flight times were limited by fuses.
The First World Championships F1A competition was on August 24 at Lesce-Bled in Yugoslavia. It was won by Oskar Czepa's Toothpick.
1953 Towing for lift In common use by this time. Presumably triggered the following year's towline length reduction.
1953 Zoom launch: straight tow This was a technique developed by the Loughboro' Club in the UK that required specially set up models. The CG's were set at 75-80%, aping the power model set up at that time, to prevent stalling and loops on release but, as a consequence, they were unstable and often stalled out of lift. Only minor differences were apparent between models: complete gliders and parts were swapped about amongst the club members. This was possible because all of the models were built on a common set of jigs. The instability of the models using this trim caused the technique to be ignored until a method of applying zoom rudder before launch was perfected.
1954 Rule change The fuselage minimum cross section rule was dropped and the towline length reduced to 50m. Lindner won with his long-nose Spinne.
1955 Thermal hunting First clear use was demonstrated by Lindner's second World Championship win with his short-nose Spinne. He was also reported to accelerate the model off the line into lift, though the model had no facilities for applying zoom rudder under high line tension.
1956 Clockwork timers. The introduction of clockwork timers that started when the model was released from the line is very significant. Liberation from fuse d/t made prolonged towing a generally accepted technique by drastically reducing the risk of losing models while promoting lift picking on tow into an essential tactic. This in turn put a huge premium on good tow stability and controllability.
Timer start systems were originated independently by Hank Cole and the late Brian Faulkner.
Brian Faulkner, then in the Cheadle Club, put a war surplus "bomb timer" into an A/2, probably in the second half of 1956. He described his timer, swinging tow hook and associated systems in an article that appeared in the 1957-58 Zaic Yearbook. The hook swung back to start the timer when the model was released from the towline. This also operated the auto-rudder and a "Negatiser" (see below). John O'Donnell was also using the system by the end of January, 1957.
Hank Cole, who was in the Cloud Dusters with John Tatone at the time, started flying with a prototype rattler-type Tatone Tick-off timer during 1956. This model appeared in the 1957-58 Zaic Yearbook as a result of setting the American A/2 duration record in 1957. The plan omits the timer but the accompanying article makes it clear that a timer was fitted and was arranged to start on release from the towline.
Commercially available clockwork d/t timers made their appearence this year, with John Tatone's original air vane type timer. This was first advertised in Flying Models in 1956.
1957 VIT on tow. Brian Faulkner's "Negatiser" was described in the 1957-58 Zaic Yearbook. This allowed a model to be towed in an overelevated condition and automatically retrimmed it for glide on release. He used it to make towing a straight tow model easier in still air and to let the flier move downwind towards the model in stronger breezes.
1958 Tatone Tick-off d/t timer The Tatone Tick-off was the first widely available clockwork d/t timer. The first advertisement appeared in Flying Models in February, 1958 and in Aeromodeller in 1959.
The first published description of using a pin attached to the towline, rather than a swinging towhook, to start a d/t timer as well as releasing the auto-rudder appears in the 1959-61 Zaic Yearbook, which contains a note from John Tatone and a design by New Zealander Bill Cook. It appears that this model was the result of a collaboration between clubmates Bill Cook and John Malkin.
1961 Zoom launch: with zoom rudder A. Awerjanov's '61 winner used a dynamic start hook for the fly-off. That flight was reported to have zoomed off "a stretched and singing towline into a banked transition without a stall". A spring-loaded extensible hook was mounted in a swinging housing. The rudder line connected to a pin extending from the hook shaft so zoom rudder was applied as the line tension increased. It did not have a towline retention latch. The hook would lean the model into its turn as the hook extended but without a latch it could not have been used for circle towing. A version of this towhook, made by A. Semekyj, was first printed in the Soviet Wings of the Fatherland magazine and reprinted in the September 1962 Aeromodeller.
1965 Offset hook circle tow. Offset hooks had been used as an alternative to an autorudder and in asymmetric glider designs for some time. The 1969 World Champs saw the first use, by a French team member, of an offset hook as a way of circling on tow. The 1969 system used a conventional open hook so the line had to be kept tight, both to keep the model circling and to prevent it releasing prematurely. Later variants used a leaf spring to stop the line falling off when slack or changed to the twanger release system.
1965 Sliding plate circle tow hook. B. Oksjema seems to have made the original sliding plate circle tow hook. It provides all the functions of its modern equivalents but the rudder settings were apparently at the control surface, not the hook.
1969 Modern circle tow. First seen in its modern form at the Wiener Neustadt World Championships. Andres Lepp added the ring retention latch as well as moving all the rudder stops to the tow hook. These were straight and circle tow, zoom and glide settings. The hook's integral timer start feature was added by him or Viktor Isaenko. This type of hook first became widely available when Bob Hatschek started mass production in 1977.
1973 VIT for circle tow. Tammy Thompson was the first to use increased incidence on tow as a way of getting a model to circle tightly on tow without tending to spiral in. Paul Crowley called it his kicker and used it on his Happy Hooker design, which had a major influence on American West Coast circle tow development.
1977 Electronic timers for F1A. An almost simultaneous development by Ken Bauer and Thomas Koster. Ken introduced the concept of line break protection by resetting the timer every time the line was pulled. His timers became available to others in 1980. Thomas developed the first commercial timer, which was released in 1983. See my F1A timers page for more details.
1985 Carbon spar with a Kevlar D-box This wing structure first appeared on Victor Isaenko's #30 model at the Livno World Champs in 1985. He introduced a full depth spar with carbon composite flanges, full width end-grain balsa web and Kevlar thread wrapping to prevent spar delamination. He replaced the usual glass/balsa D-box with a Kevlar/epoxy shell for increased torsional rigidity, though he retained straight balsa ribs and a balsa TE.
1986 Wing wiggler for F1A. The two position wing wiggler was developed by Sergey Makarov. This sets higher incidence on the inner wing while the model is on tow, thus allowing tighter circles without any danger of spiralling in. On launch the wing moves to its glide incidence setting. Mikhail Kochkarev and Sergey Makarov made a three position wiggler in 1994. This allows seperate inner wing incidence settings for straight tow and launch, circle tow and glide.
1988 Carbon structures. The first carbon composite wings (a full depth spar with carbon/epoxy flanges and the D-box shell, rib cap strips and TE all of carbon/epoxy) were made by Mikhail Kochkarev and Sergey Makarov in the winter of 1988/89. Similar wings were used in 1990 by Stefan Rumpp in Belgium, then by Viktor Stamov during the Antonov Cup at Kyiv.
1989 Bunt launch. Victor Tchop's #40 was the first major appearance of a bunt model at the Argentine World Championships. The system worked well, but it was installed in a wooden glider and could not be launched really hard without destroying the model. M&K retrofitted a bunt hook to their first carbon model after seeing Victor Tchop flying his bunter during team training earlier that year.
1998 Servo tow hook. Ken Bauer brought the first model equipped with a tow hook equipped with a servo-driven latch to the Maxmen contest in February 1998.
2004 Flapped wings. Allard van Wallene flew the first successful flapped F1A in 2004. This was followed by the Aringer/Nyhegyn in 2005. These models were developed to improve launch height by reducing drag during on-line acceleration and cruise phases. The two approaches are aerodynamically different: Allard uses conventional flaps, so moving them changes the wing's incidence relative to the fuselage while the Aringer/Nyhegyn design changes the wing camber, leaving the incidence largely unchanged.

Sources

The timeline was initially constructed from Jim Baguley's design series in the 1961/62 Aeromodellers, discussions with Lee Hines and my own recollections. At this point I sent an e-mail to SCAT Electronic News asking for aid in determining the missing dates. As a direct result Sean O'Connor helped enormously by researching the Zaic Yearbooks: I don't have copies of any of them. Thanks are also due to Ron Bennett, Ron Chernich, Bill Cook, Tim Dannels, Dave Dent, Trevor Faulkner, Juha Heikkinen, Mikhail Kochkarev, Rene Limberger, Sergey Makarov, John Malkin, John O'Donnell, Stefan Rumpp, Gerd Aringer and Allard van Wallene for helping to clarify various points.