Whirlwind Fighter Project: July 2015


Chris Hayward

July Newsletter

With our second AGM now behind us the minutes of which are on our Project Web Site, the build is going from strengh to strengh and the workshop are now cutting the sheeting panels for the rear fuselage. I would like to thank all those who attended the AGM and especially the speakers who gave their time for free.

Short update on the project by Matt Bearman

Jim Munro on "Ghosts of the Whirlwind".

Dave Birch from the RR Heritage Museum on the Peregrine.

Mike Coghlan on his father Humphrey who flew with 137 Sq.

Roger Bailey from the Shuttleworth Trust.

Thanks also to Mike Daley MBE who presented the Project with a Whirlwind Painting so that we can raise money for the build.


Copyright Mike Daley MBE

The Painting shows our P7056 " Pride of Yeovil" flown by John McClure on convoy Patrol. This will shorty be for sale via the forum shop and is a one off so grab a chance to buy something unique and help us build this plane.

We had several kind offers of Painting and prints all have been recieved with thanks as it all helps in the end.

The raffle and donations totaled to £225.

We have also recieved some more donations from the following people.

£10 from Andy Sephton, Sandy, Beds

£60 from Dave Eadsforth, Alresford, Hants – his comments were ‘For another bag of rivets’

£40 from Colin Smithson

A big thanks to all who contribute, we accept all donations of money via Paypal on our forum site, every little helps.

Donate here.

For those who are interested or for those who cant sleep the minutes of the AGM can be found here..........Minutes

W100

With the anniversary of Westland being held next month and to which we as a project have been invited to attend along with our rear fuselage, AgustaWestland have released this short video on Youtube which is well worth watching.

AgustaWestland W100

Book Club

A new book has now been released by our very own Dave Gibbings MBE and he has also recieved an award from the American Helicopter Society so a very busy and rewarding year for him.

A Quiet Country Town:

A Celebration of 100 Years of Westland at Yeovil

By David Gibbings

It has been 100 years since the first airfield was established in the country town of Yeovil. Since 1915, aircraft have been designed, manufactured and tested at Westland, including the Lysander, used to transport British agents to Europe during the Second World War.

In 1948 the company focused solely on helicopters and its aircraft have been sent all over the world since then, used in lifesaving with Air Ambulance and Search and Rescue and deployed in warfare such as Balkans, Iraq and Afghanistan. To celebrate the centenary of the UK’s only major helicopter manufacturer, David Gibbings has collated an anthology of writings that retell Westland’s history and its special relationship with Yeovil, which has rarely been quiet since the first aircraft took off from the airfield that now lies at its heart.

Published by History Press: ISBN 978-0750962421

RRP £16.99

For a list of all of Daves books please follow this link

Books by David Gibbings

David Gibbings MBE

The American Helicopter Society (AHS) has presented Dave with the prestigious ‘John J. Schneider’ trophy for historical achievement. The award was presented on the 6^th of May at their annual forum in Virginia Beach, the award recognises distinguished achievement in encouraging appreciation of, and enhancing access to the history and legacy of vertical flight.

Dave joined the Royal Air Force in 1949 as an RAF apprentice at Halton. He qualified as Navigator but joined Fairey Aviation in 1955 to work on guided weapons. In 1959 he was transferred to the aircraft division to work on Tip-jet units for the Fairey Rotodyne, he moved to the test facility at White Waltham where his duties included flying in the aircraft as Flight Engineer.

After the Rotodyne was discontinued he was transferred to the Flight Test Department to work on Scout and Wasp helicopters, and Gannet. He was moved to Yeovil in 1964.

Dave remained in the Flight Test Department at Yeovil until he retired in 1993, during that time he flew with the whole range of Westland products, and played a leading part in the Lynx development programme and was one of the crew on the first flight. He was also responsible for helicopter icing trials in the 1980s, the work carried out by Dave and his team has led to safe flight in icing for helicopters. He was Chief Flight Test Engineer when he retired.

David has continued to work as a consultant, aviation artist and author in spite of Parkinson’s disease. Previous recipients of the ‘John J. Schneider award’ include Serge Sikorsky, and Jean Boulet. He was also awarded the MBE in 2014, and takes pride in the fact that both these awards have been received since his 80^th birthday.

Thanks to Joel Diggle who has sent me a photo of this rememberance plaque that he found.

"At the weekend I was camping in the Forest Of Dean at The Speechley Hotel for a Best of British Proms in the Park.
At the entrance to the field was this memorial stone, thought it might be of interest to members on this page.
You never quite know past happenings on the ground when you pitch your tent".

Derrick Ellis Prior was an RAFVR Sergeant Pilot with A flight of 263 Squadron. He flew his first Whirlwind Operation on the 15th of October 1941. He was a well known and popular member of the Squadron due to his sense of humour. Unfortunatly he was killed while on a Co-Operation searchlight exercise when P7044 crashed near Coleford, Gloucestershire

Whirly Stories

P7048

She joined 39MU at Colerne on the 27th of May 1941, then was sent to 137 Squadron in November 1942 after being damaged in June of the previous year.She suffered a tail wheel collapse while at Matlaske after hitting a drain. She was again damaged in January 43 and again April 43 by flack while being flown by Eddie Musgrave. She was later taken on by Westland and registered G-AGOI and used as the firm hack. She was later scrapped on site.

Operational hours 123:25

Matt Bearman askes a question...WHAT’S GOING ON WITH THE AREA BELOW THE COCKPIT?

Time for another arm-waving session. There has been much debate around this area:

· Is it flat, or just appearing so where several subtle curves meet?

· Is it vertical, or does it break convention by being at an acute angle to the wing, as indicated by the wind tunnel model data tables?

· Why the odd, slightly awkward slab-sided effect anyway?

I confess I was on the wrong side of this debate – I now stand corrected, and somewhat astounded by what Petter was actually doing here.

To understand his surprising innovation it is necessary for a minute to go back to the 1930’s and aerodynamic thinking at the time.. it was recognised that if one went beyond the vertical and the angle between the fuselage side and the wing became acute, one would get a serious drag penalty, called ‘interference’ drag. This was demonstrated by tests both side of the Atlantic, eg http://naca.central.cranfield.ac.uk/reports/1936/naca-report-540.pdf

These tests were on circular or ovoid section fuselages, and as one moved the wings up and down, the interference drag was recorded. Low wing arrangements created the most drag, and it was all put down to there being an acute angle formed between the local fuselage side (at the bottom of the ‘circle’) and the wing. And there stood the orthodoxy.

Designers at the time strove to create fairings between wing trailing (lifting) portion and fuselage to overcome this. All mainstream fighter designs of the period acquired a fairing, being low-wing and round-fuselage – from the big one on the Spitfire to little ones such as on the 109.

However, the Whirlwind did not. Furthermore, it had an acute angle between fuselage and wing. What on earth did Petter think he was doing?

The answer lies deep in a NACA Technical Note from 1938. TN.642 also tested what they called ‘Straight Sided’ wing intersections. In these, round fuselages had been locally altered around the wing junction to produce a straight ‘seam’ – the fuselage section was flat and vertical where it met the wing. The drag was reduced enormously compared to circular sections, and the report concluded “A modification of a round fuselage to provide straight side junctures appeared very effective aerodynamically”

Crucially, the wing/fuselage intersection was straight and parallel to long axis when viewed in plan form. This was not enlarged upon by the Tech Note, though it did describe the junctions as ‘straight’ rather than just the sides being ‘flat’. This must have been noticed by Petter!

Here’s the thing. The slab sides on the WW are not a flat surface. In fact they are ever so slightly twisted, as shown by the positioning of point ‘A’ in the diagram and table above such as to ensure a constant distance from centreline as the lifting, trailing part of the aerofoil intersects the inclined plane. The wing/ fuselage ‘seam’ as viewed from above is STRAIGHT AND PARALLEL.

What Petter had picked up on was this. It was not simply the angle of wing to fuselage that caused interference. In fact it was irrelevant, despite what aerodynamic texts at the time were saying (and what a lot of on-line resources still say now).

What is important is the straightness of the wing/fuselage intersection. When you intersect the curve of an aerofoil with the curve of a fuselage, you get an even more curved ‘join’. That was what caused the interference. This is backed up by the curious effect whereby if you increased incidence, you increased interference drag. What you are doing is decreasing the radius of this curve.

So, the answer is to correct the fuselage profile locally to make this join straight and parallel when viewed in plan, as in the Airbus design study below. Upper bad, Lower better:

This is exactly what designers of airliners, conventionally low-wing and tubular, started doing in the 1960’s thus dispensing of fairings. And it is what Petter did in 1938.