Date:	Sunday 26 August 1951
Time:	day
Type:	Handley Page HP88 prototype
Owner/operator:	Handley Page Aircraft Company
Registration:	VX330
MSN:
Fatalities:	Fatalities: 1 / Occupants: 1
Aircraft damage:	Destroyed
Location:	Stansted Airfield, Stansted, Essex -   United Kingdom
Phase:	Manoeuvring (airshow, firefighting, ag.ops.)
Nature:	Test
Departure airport:	Stansted Airport, Stansted, Essex (STN/EGSS)
Destination airport:	Stansted Airport, Stansted, Essex (STN/EGSS)
Confidence Rating:	Information is only available from news, social media or unofficial sources

Narrative:
The single HP.88 aircraft was designed to Air Ministry Specification E.6/48 as an aerodynamic testbed for the proposed Handley Page Victor V-bomber.

To save time and cost it was decided to base the fuselage on the Supermarine Attacker. This was then changed to the Supermarine Type 510 which had already been redesigned with a swept wing. In the event, the many changes led Supermarine to give the design its own designation as the Supermarine 521. Detail design was contracted to General Aircraft (GAL) at Hanworth Aerodrome, but after GAL merged with Blackburn the work was moved to Brough Aerodrome and the design was given the Blackburn/SBAC designation YB-2. The aircraft was allocated military serial VX330. To complicate matters still further, the contract had been originally awarded to General Aircraft Ltd., of Feltham, Middlesex as the GAL 63. Thus, VX330 was one aircraft with four names!

The HP.88 had a 0.36 scaled-down equivalent of the Victor's crescent wing and T-tail with slab tailplane. However where the Victor had a mid wing, the Type 521 set the wing low on the fuselage. Also, the Victor design continued to be refined, so the HP.88 was no longer representative of the Victor. The HP.88 wing featured inboard trailing-edge flaps, which badly affected trim when deployed. The tailplane was too small to counter the trim change, so a system was developed where the ailerons deflected upwards together to balance the trim forces. The system was wholly automatic with no pilot intervention, and in the event of any failure all surfaces would return to their normal positions. Uprigging the ailerons was a technique used during flutter testing on the second prototype Victor. The fin flutter speed was critically dependent on the steady airload on the tailplane. With both ailerons rigged in the up position the pressure distribution around the wing was altered and hence the trim load required from the tailplane.

The Supermarine fuselage was delivered to the Blackburn factory at Brough, where it was modified and the wing fitted. The completed HP.88 was taken by road to Carnaby near Bridlington, where it was flown for the first time on 21 June 1951. Testing by Blackburn revealed pitching oscillations at speeds above 230 knots. Modifications to the tailplane gave acceptable behaviour, with only minor oscillation, up to 450 knots (Mach 0.82). The HP.88 was delivered to Handley Page and on 6 August 1951 was flown to Stansted for further testing.

On 26 August 1951, in preparation for the 1951 SBAC Air Display at Farnborough, the HP.88 carried out a high-speed pass at 300 ft over Stansted, and was seen to start a pitching oscillation before breaking up in mid-air. The "black box" flight recorder subsequently showed pitching accelerations of +/-12g. The cause was traced to a tailplane control system servo instability involving a bob-weight that had been added as a safety measure.

The HP.88 had only flown 14 hours in 26 sorties over a lifetime of just 36 days, and had little time to gather useful information, but the loss of the aircraft was of little significance to the V bomber project; two prototype Victors were already nearing completion by the time of the HP.88's first flight.

Pilot of VX330:
Flt Lt D.J.P. Broomfield DFM, Handley Page Test Pilot - killed

1. Halley, James J (1999). Broken Wings – Post-War Royal Air Force Accidents. Tunbridge Wells: Air-Britain (Historians) Ltd. p.118. ISBN 0-85130-290-4.
2. Last Take-off: A Record of RAF Aircraft Losses 1950 to 1953 p 172
3. National Archives (PRO Kew) File BT233/63: https://discovery.nationalarchives.gov.uk/details/r/C424184
4. National Archives (PRO Kew) File AVIA 5/31/S2539: https://discovery.nationalarchives.gov.uk/details/r/C6578385
5. https://1000aircraftphotos.com/Contributions/Visschedijk/6713.htm
6. https://www.thunder-and-lightnings.co.uk/memorial/entry.php?id=213
7. https://www.secretprojects.co.uk/threads/general-aircraft-from-st-1-to-gal-65-%E2%80%94-the-definitive-index.21250/page-2#post-209859

26 August 1951. The sole Handley Page HP.88, British research aircraft, built to test the aerodynamics of the Victor design, broke-up in mid-air due to a tailplane servo control system failure while carrying out a high-speed pass over Stansted. pic.twitter.com/tcdL5FqlzJ

— Ron Eisele (@ron_eisele) 26 August 2018

Date/time	Contributor	Updates
26-Dec-2010 00:38	angels one five	Added
26-Dec-2010 00:41	angels one five	Updated [Date]
15-May-2012 13:16	ryan	Updated [Source, Narrative]
30-Nov-2012 03:36	geoffddv	Updated [Embed code, Narrative]
16-Jun-2014 21:36	angels one five	Updated [Time, Aircraft type, Registration, Operator, Location, Departure airport, Destination airport, Embed code, Narrative]
23-Dec-2019 22:18	Dr. John Smith	Updated [Time, Location, Departure airport, Destination airport, Source, Embed code, Narrative]