Archived posting to the Leica Users Group, 2015/08/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Douglas, It's not all about speed. Extra horsepower also means better take-off and climb performance, and, with modern molded cowlings, necessary to finish up the engine installation, the airplane drag coefficient is reduced. The basic aircraft structure is not usually modified, so the top speed for which the airplane was certified remains the same. But, with the larger engines, cruising at 65-75 percent power will reduce the fuel consumption while still propelling the airplane near its maximum cruise speed. The certificated airplane limits still apply with larger aircraft, as well. A local automobile dealer whom I know has a Beech King Air 90 turboprop twin which, before he purchased it, was retrofitted with larger Pratt and Whitney power plants. He told me that, because he must adhere to the original certification limits for the airframe, he cannot use the additional horsepower until he reaches 15,000 feet. As he climbs on up to altitudes above 20,000 feet, where he usually cruises, the additional power pays off in increased climb rate and speed. Jim Nichols Tullahoma, TN USA On 8/12/2015 9:37 AM, Douglas Barry wrote: > Interesting, Jim, but a question, wouldn't shoving a bigger engine > with more horse power into that airframe be really invoking the law of > diminishing returns as fuel consumption would surely jump for very > little speed boost? > > Douglas > > > ----- Original Message ----- From: "Jim Nichols" > <jhnichols at lighttube.net> > To: "LUG at Leica-Users.org" <lug at leica-users.org>; "Olympus Camera > Discussion" <olympus at thomasclausen.net> > Sent: Tuesday, August 11, 2015 7:31 PM > Subject: [Leica] IMG: Globe/Temco Swifts > > >> A flight of three beautiful Swift aircraft visited our airport this >> morning. >> http://www.gallery.leica-users.org/v/OldNick/Swifts.jpg.html >> >> These all had different modifications. Each had larger engines. All >> had the original control wheels replaced by fighter-like control >> sticks. This one was closest to the original appearance, polished >> aluminum. >> http://www.gallery.leica-users.org/v/OldNick/Polished+Swift.jpg.html >> >> It was the only one that had the window left open for a panel shot. >> http://www.gallery.leica-users.org/v/OldNick/Swift+Panel.jpg.html >> >> It also had the original leading edge slot to maintain better flow >> over the ailerons at low speeds. >> http://www.gallery.leica-users.org/v/OldNick/Slots+Open.jpg.html >> >> The red Swift had the slots closed. The Swift has long led to a lot >> of hangar talk about these slots. Most agree that there is not much >> speed to be gained by closing them unless a lot of horsepower has >> been added, resulting in speeds above 170 mph. Everyone seems to hold >> to his own opinion about how closing the slots affects stall >> characteristics. >> http://www.gallery.leica-users.org/v/OldNick/Slots+Closed.jpg.html >> >> All photos by my iPhone. >> >> Comments and critiques welcomed. >> >> -- >> Jim Nichols >> Tullahoma, TN USA >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information >> > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >