TAKO. INTERNET SEIT 1996.
Olympus-OM

Re: [OM] IMB: TBM 850 at the Airport

Subject: Re: [OM] IMB: TBM 850 at the Airport
From: ChrisB <ftog@xxxxxxxxxxxxxx>
Date: Sat, 31 Aug 2019 10:03:11 +0100
Perhaps the tip exceeds a local Mach value rather than the actual speed of 
sound, Bill. 

Chris

C M I Barker | Gamlingay


> On 30 Aug 2019, at 06:52, Bill Pearce <billpearce@xxxxxxxxxx> wrote:
> 
> I know a guy here that is a test pilot on the Beech AT-6, and has a PhD in 
> aero engineering, who says no prop tip ever goes supersonic. But hes kind of 
> a blustery loudmouth who thinks he know everything, so I'm thinking his PhD 
> is from ITT Tech.. 
> 
> ----- Original Message -----
> 
> From: "Jim Nichols" <jhnichols@xxxxxxxxxxxxx> 
> To: olympus@xxxxxxxxxxxxxxxxx 
> Sent: Friday, August 30, 2019 12:24:56 AM 
> Subject: Re: [OM] IMB: TBM 850 at the Airport 
> 
> Mike, 
> 
> A lot of research has gone into optimizing propeller design. One 
> problem has been dealing with tip speed. If the tip speed goes 
> supersonic, much of your energy goes into noise and tip losses. Hence, 
> as horsepower goes up, the prop can't just get larger in diameter. They 
> try to hold the diameter small enough to avoid the tip losses while 
> increasing the ability to absorb horsepower by optimizing the number and 
> shape of the blades. 
> 
> If you have ever heard a WWII North American AT-6 or Navy SN-J at an 
> airshow, you probably have an idea of the sound of a propeller going 
> supersonic. 
> 
> Jim Nichols 
> Tullahoma, TN USA 
> 
>> On 8/29/2019 6:48 PM, Mike Gordon via olympus wrote: 
>> Fuel burn related to all those blades on the prop? I am no engineer but 
>> would seem efficiency would be down with each blade turning in the wake of 
>> the previous. 
>> Probably a myriad of other variables that would not even know to think about 
>> but the number of blades strikes the lay person as unusual. 
>> 
>> Mike 
> -- 
> _________________________________________________________________ 
> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus 
> Archives: http://lists.thomasclausen.net/mailman/private/olympus/ 
> Themed Olympus Photo Exhibition: http://www.tope.nl/ 
> 
> 
> -- 
> _________________________________________________________________
> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
> Themed Olympus Photo Exhibition: http://www.tope.nl/
> 
-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/

<Prev in Thread] Current Thread [Next in Thread>