![]() These gearboxes have a lower ratio than the standard item. At the other end of the engine, a slow-turning transport nose case has been fitted in place of the original. The reason for the fitment of the -23 impeller wheels is that more advanced turbine technology was incorporated into the design of the turning vanes which, due to their higher efficiency, will usually provide an increase of around 10” of manifold pressure. Replacing the original is the component from a V-1650-23 Packard Merlin, originally fitted to the P-82 Twin Mustang – only a handful of these were made due to the limited production run of the P-82. One of the numerous changes made in order to gain more manifold pressure is the fitment of a different supercharger impeller. With both engines sharing the same 6” stroke, the parts are almost a straight swap, the Allison conrods fitting to the Merlin crankshaft with the use of adaptor shells. If you were to directly compare both the Allison and Merlin components, you’d see the Allison conrods have considerably more material and structure to them, and so bear the higher stresses of a racing engine far better. This is a common modification for race Merlins, as at the high boost settings – also referred to as manifold pressure and noted in inches (“) of Mercury – used on racing engines, original Merlin conrods are susceptible to bending, often leading to detonation of the engine and the conrod ending up outside the case. Steve explains that a number of major modifications were made to the engine to improve performance, starting with the fitment of Allison conrods. As per a standard Mustang, Voodoo is powered by a Rolls-Royce Merlin – but this is no ordinary Merlin. Everything on the aircraft is geared for speed – even the paint, with the famed purple scheme lost and plain white paint applied as a weight-saving measure in preparation for the record attempt. Voodoo, the aircraft Steve used for the record attempt, is a heavily modified Mustang – those familiar with the Reno Air Races will know the aircraft as the (previously) colourful purple racer owned by Bob Button. Under these new conditions, Will Whiteside captured the current C-1e record at 318mph in Steadfast in 2012. The weight class Steve would be contesting was the C-1e class, for aircraft with a take-off weight of between 30kg – the same class that Rare Bear would have fallen into had it been weighed at the time of its 1989 attempt. The old record had stagnated somewhat, with the record unchanged since it was set by Rare Bear, and so allowing lighter classes of aircraft to contest their own records made the sport accessible for more pilots. A further change to the record was to break it down into weight classes. In order to closely replicate the conditions of the retired record, Steve decided to fly the older, narrower course – his flying so accurate in the event, he passed through an air corridor just 30m wide on each of his four high-speed runs. Previously the width of the course between the speed traps was a challenging 100m (330ft), now increased to 500m (1640ft) under the terms of the current record. One of the main reasons for the retirement of the old record, and the one which would have the most impact for Steve’s attempt, was an increase in the corridor width. To better understand the scenario, it’s worth considering the conditions of both retired and current speed records. This has been subject to considerable controversy over the past few weeks, predominantly stemming from confusion over exactly which record has been set. Though Steve would need to best this in order to claim the current record, the team ambitiously set their sights on breaking the retired iteration of the same record, set at 528mph by Lyle Shelton flying Rare Bear in 1989 regardless of the fact that this would not be formally recognised, Steve and the Voodoo crew pressed on with their attempt to top both formal and retired speed records in the spirit of competition. The record to beat was a conservative 318mph, set in 2012 by Will Whiteside flying Yak-3 Steadfast. Interviewed shortly after the record was set, and in the days leading up to his participation in the 2017 Reno Air Races, Steve offers The Vintage Aviation Echo a fascinating account of his record-breaking run. On 2 September 2017, Steve Hinton, Jr set a new 3km Absolute Propeller Driven Piston Powered Aircraft (C-1e class) record, achieving an average speed of 531.53mph over four consecutive passes in highly modified P-51 Mustang Voodoo. ![]()
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