Issue 71 – Published and distributed in April of 2019. Click on image below to read the table of contents
In the editorial space of this new edition we present an obituary of John Barker, the well known English modeller, who died at the beginning of 2019. He was 91.The obituary follows John from his first job in his native city of Grantham in Lincolnshire, UK, where he started as a draughtsman for a company that specialized in earth-moving equipment, Aveling-Barford. He moved afterwards to the aircraft industry in his profession of draughtsman, joining Vickers at Brooklands in Surrey, where he met the famous aircraft designers Roy Pierson and Barnes Wallis. His next stop was de Havilland in Hatfield, Herts, where he worked in a number of projects, including the multi-national Concorde supersonic transport. This was an extremely complex project, all in the new territory of supersonic aerodynamics, and ultimately quite successful. A managerial job in Manchester tempted him and moved there with his family in 1965, remaining in that job until retirement. There was a final move to Baildon in Yorkshire to be in closer contact with his family. During the Manchester years John developed a great mastery of programming for the computer and of the spreadsheet program Excel. This was put to very good use in developing some superb spreadsheets for Propeller design, Neutral Point Determination, Allowable number of turns in a rubber motor, and Conic camber line Airfoils among others. His most famous model designs came early in his life, while in Grantham, and they were the Hepcat Lightweight Rubber model, published by Aeromodeller in 1946 at the young age of 19 and the Lulu II glider which saw the light in November 1949, also in Aeromodeller. Although many other designs flowed from his pen, these two remained the favourites of the modellers. During the peak years of Free-Flight modelling in the UK, the 1960’s, John presented in Aeromodeller a long series of articles (in 10 installments) on aeromodelling instruction, “Let’s go flying”, this was an extremely interesting series destined for the novice builder and which included two more designs by John, the Downbeat A/1 glider and the Gigi power model.
Two P-30 models of different provenance are included in the second article of this new issue, the “Torpedo” by Tomás Benes of the Czech Republic and the “Racing P-30”, an older model, conceived by Georges Matherat , the famous French designer. Both models are linked by their rapid climbing ability, although they are quite different in many important details.
Alexandre Cruz of Sao Paulo, Brazil has adapted the Starduster design of Sal Taibi, scaling it down to 20″ span, for an E20 model, whose electric motor is powered by a super-capacitor. The resulting model, that weighed less than 30 gr. has an impressive performance, and is capable of doing nearly 2 min. in neutral conditions. A plan and sufficient electronic gear details are included, so that it would be easy to replicate this interesting model.
The second part of the Marquardt Story by Sergio Montes looks at the beginning of the professional career of John Marquardt, after he left Caltech in 1943, now an Aeronautical Engineer. He joined Northrop during wartime to work in the XB-35 Flying Wing bomber and then after a year or so set out his own course by creating the ultimately very large and successful Marquardt Industries that had a workforce of more than one thousand engineers and workers during the 1950’s and 1960’s. In these postwar years Marquardt Industries was the leader in the design and construction of Ramjets, principally utilized for highly supersonic missiles, and also as auxiliary power units for turbojet aircraft. Marquardt moved to increasingly large premises in several locations in California as his contracts with the USAF increased in importance and value. Starting in 1949, a former aircraft plant in Van Nuys, California, was considerably enlarged for this purpose. The last part of this story will be published in the July 2019 issue of Free Flight Quarterly.
George Schroedter created Champion Model Products in 1979 in the Los Angeles area of California, with the purpose of marketing a very high quality kit, at first a Coupe model simply known as the Champion Coupe. This model was originally intended as suitable for beginners, with easy construction of perfectly finished parts, but it was quickly found that it offered excellent contest performance and won the US Nationals F1G competition in 1979. A Mulvihill model based on the Champion Coupe quickly followed, using the wing, stab and propeller of the Coupe, but with a longer built-up fuselage holding about 30 gr of rubber. The climb was spectacular, getting so high that propeller fold could not be seen, according to the designer. George Schroedter’s masterpiece was next, a kit for a Wakefield (F1B). This was appropriately called “Wake-Up” and followed the proportions set by Bob White in his F1B designs of the era, but with many detail differences. The design was also intended for the novice flyer, with particularly easy trimming qualities. Just like the Coupe, it proved very suitable for competition and George Schroedter made in 1983 the USA Team that flew in the Wakefield competition in Australia, in spite of his limited contest flying experience. A last model in this series was the Champion P-30, that came in 1983, of very orthodox lines and rather similar in appearance to the “Wake-Up”. This article , by Sergio Montes and Marty Schroedter will continue in the July issue with a further look at the details of the Wake-Up kit produced by Champion Model Products.
We continue with part 2 of the story of Polish Model Engines designed by Stanislaw Gorski, an article written by Adrian Duncan. The designer, Gorski, went to work in 1955 for the PZL aircraft factory, which was producing a number of Russian-designed aircraft, such as the MiG-17 fighter and the Antonov AN-2 biplane transport. PZL found that the production of model engines fitted well with the development of an aeronautical conscience in the Polish youth. The engines produced in this facility were the Jaskolka 2.5 and 1.5 cc Diesels, some were sports models of shaft valve, plain-bearing type, but also, by 1958, variants with ball-bearing shafts and reed-valve induction appeared, of pleasing appearance and excellent finish and fits. The article is concluded with part 3 in the July 2019 issue of FFQ.
The product of another small scale kit manufacturer is reviewed by Sergio Montes. Lars Larsson created in Sweden a kit of a high-performance F1A model, with a balsa, spruce and ply construction and a carbon boom, suitable for a novice builder. The model, named Skylady II by its designer, was conceived for straight and circle tow. Calculations included in the article show that its sinking speed is only marginally greater than in top-notch F1A models.
It is not frequent to find canard models of any description, so the articles of an expert in that topic, Clarence Mather from USA, are always interesting. Mather experimented with the design of rubber powered canards which use a single blade pusher folder. Mather found that in general canard models are more unstable than tractor models and that fin placement and size were quite critical. After some protracted development wing and stab proportions were determined, as well as fin size and position, CG placement and decalage. Mather offers a first design, which he called “King of Diamonds”, and that embodies the lessons of the experimentation with pusher canards. It flew quite well and had almost competitive performance, at least in calm air. This first part of the article follows Mather’s presentation in the April 1948 issue of Flying Models. Essentially this article was continued in the 1957-58 Zaic Yearbook with an extended discussion on the development of a stable and competitive canard of larger size.
Jim Baguley continues his series of Contest Glider Analysis, looking now at the glide stability of the A2 models (F1A now). In this article he develops a graphical method to determine the ideal tail area and moment arm from the CG to insure stable flight. The graphical method is based on the study of the 45 models that have been the basis of this series, models of different origins and proportions. Baguley appears not to favour the Tail Volume coefficient as a guide to stability, for reasons that he discusses in the article.