The 120 HP Argyll: Pioneer Sleeve Valve Aero-Engine

Over the course of piston aero-engine history, the sleeve valve type has been quite well represented. In Britain, thousands of Bristol and Napier engines with this unique kind of mechanism were manufactured. In America and Germany, interest in the apparatus was such that a lot of prototype construction and testing was carried out.

Thus, by the end of the piston engine era, sufficient experience of the sleeve and poppet valved kind had been obtained to allow meaningful comparative conclusions to be drawn between the two types. Of course there were pluses and minuses but, in an overall sense, it was clear that the sleeve valve never provided a quantum leap in engine performance over the poppet valve type. If it had, it would have replaced the poppet valve quickly and completely.

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Gearing for Gearheads, Part 3

Part 1 presented the basic geometry and dimensions for several Rolls-Royce Merlin Propeller Speed Reduction Unit (PSRU) gearsets. Part 2 continued with derivations of defining formulae of tooth beam equivalent dimensions, tooth stresses, rub velocity, pitch line velocity and contact ratio. Part 3 will examine how gears are made, describe the materials and processes involved, complete the analytical tools needed to evaluate gearsets, evaluate the relative merits of the gearsets already discussed, and present observations and conclusions.

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Aero Engine Drawings by Frank Munger

Austro-Daimler 120 HP, Circa 1912

One Second on the Course in Dreadnought

At a race weight of 6.25 tons, the trick Pratt & Whitney R-4360-63 powered T.20 Sea Fury Dreadnought is truly the big kid on the air racing block. Built, owned, and flown by the late Frank and sons Brian and Dennis Sanders, this two-seat masterpiece has turned the pylons as fast as 458.9 mph by virtue of the clean, highly detailed airframe and the 3,800 horses that tread within her custom cowling. Dreadnought has won the National Championship Reno Air Races twice, and finished second 13 times. To simply call this airplane large and fast, while certainly accurate, diminishes the fantastic complexity required to attain such impressive performance. If you could examine a single second of time while Dreadnought is hard at work, engine at 3,000 rpm and 72 inches of manifold pressure, just 70 feet off the deck at 450 mph on the Reno course, what would you find?

Re-Inventing the Liberty Cap, Part 2

We did make that fly-in at the Air Force Museum (see Part 1) and had a grand time. Meeting the people and once again seeing the aircraft provided more than sufficient motivation to carry us through our next phase, from components to complete assembly. A few hours time viewing complete Liberty engines and the minor cap variations up close helped to reaffirm our previous deductions and analysis. Once back at our shop, we felt as though the toughest part of the project was now behind us. In that we were only partially right.

Report from the 3rd Annual AEHS Convention

I flew from California to Connecticut in early July to attend the 3rd AEHS convention. The AEHS has almost 1,000 members, with a fair number based overseas. Three attendees flew over from the UK and another arrived from Italy. The convention venue in Connecticut, just southeast of Bradley International Airport, was near Pratt & Whitney (P&W) HQ in East Hartford and the New England Air Museum (north side of airport in Windsor Locks), which we did explore at length. Around 55 hard-core aero engine enthusiasts ("motor heads") attended.

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Reno 2006 — Radial Gold

Again, Reno earns its reputation for being the home and heart of the world’s fastest motor sport — Air Racing! What a week, so much happened, so much to see and hear! Fortunately, no one got hurt, and the airframes finished in pretty good shape. Unfortunately, more than a few engines didn’t.

The Reno Air Races start a year before race day when teams from all around the country begin the arduous process of turning their dreams into air racers. For some reason this process, more often than not, results in a crash program in the final months to get airframe and engine modifications completed, or simply the effort to ready a stock airplane for a week of continuous high power operation. That the field of 27 Unlimited airplanes (three divisions of nine racers each) was backed up by four "Conditional" airplanes meant that there was a lot of competition.

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