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Author: Nick O'TymeNick O'Tyme Date: Nov 5, 2007 00:33
I was watching Red Bull on the w/e and noticed all aircraft had three bladed
props.
It got me wondering - what are the pros and cons of multi-bladed props.
Yeah, I know two bladed are multi but I mean greater than two. The Spitfire
at the aircraft museum has a five bladed prop.
Are they more efficient? Is the drag created, offset by the increased
efficiency (pretty obvious otherwise the wouldn't have more than two
blades).
cheers
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Date: Nov 5, 2007 00:44
Nick O'Tyme wrote:
>> I was watching Red Bull on the w/e and noticed all aircraft had
>> three bladed props.
>>
>> It got me wondering - what are the pros and cons of multi-bladed
>> props. Yeah, I know two bladed are multi but I mean greater than
>> two. The Spitfire at the aircraft museum has a five bladed prop.
>>
>> Are they more efficient? Is the drag created, offset by the increased
>> efficiency (pretty obvious otherwise the wouldn't have more than two
>> blades).
>>
>> cheers
Ya know, Nick O' that in the US in the '50s, there was also an after-market
single bladed prop for GA aircraft.
--
Cheers
Dave Kearton
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Author: Alpha_77DXAlpha_77DX Date: Nov 5, 2007 00:49
>I was watching Red Bull on the w/e and noticed all aircraft had three
>bladed props.
>
> It got me wondering - what are the pros and cons of multi-bladed props.
> Yeah, I know two bladed are multi but I mean greater than two. The
> Spitfire at the aircraft museum has a five bladed prop.
>
> Are they more efficient? Is the drag created, offset by the increased
> efficiency (pretty obvious otherwise the wouldn't have more than two
> blades).
>
> cheers
>
The lower the number of blades the more efficient the prop.
The problem arises when big horse power is involved, the blades have to be
longer, and the undercarriage has to be longer. By adding more blades the
power is absorbed without the tips digging holes in the runway.
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Author: JDJD Date: Nov 5, 2007 01:14
Nick O'Tyme wrote:
> I was watching Red Bull on the w/e and noticed all aircraft had three
> bladed props.
>
> It got me wondering - what are the pros and cons of multi-bladed props.
> Yeah, I know two bladed are multi but I mean greater than two. The
> Spitfire at the aircraft museum has a five bladed prop.
>
> Are they more efficient? Is the drag created, offset by the increased
> efficiency (pretty obvious otherwise the wouldn't have more than two
> blades).
>
> cheers
The horsepower that can be absorbed by a propeller is dictated by the blade
area and rpm (higher rpm, less area needed). No problem for low powers, but
problems arise with higher powers - increase in blade length is limited by
the undercarriage height, and ultimately, even if this is not a problem,
compressibility effects due to the airspeed past the tip approaching Mach
1. Reducing the rpm to limit this effect means you need more area.
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Author: Stealth PilotStealth Pilot Date: Nov 5, 2007 01:49
On Mon, 05 Nov 2007 20:14:25 +1100, JD spamlesstpgi.com.au>
wrote:
>Nick O'Tyme wrote:
>
>> I was watching Red Bull on the w/e and noticed all aircraft had three
>> bladed props.
>>
>> It got me wondering - what are the pros and cons of multi-bladed props.
>> Yeah, I...
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Author: jw²jw² Date: Nov 5, 2007 03:16
Nick O'Tyme wrote:
> I was watching Red Bull on the w/e and noticed all aircraft had three bladed
> props.
(snipped)
===
Three blades mean a smaller diameter, allowing them to fly lower?
JW² (sorry)
===
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Author: Nick O'TymeNick O'Tyme Date: Nov 5, 2007 04:37
> Nick O'Tyme wrote:
>>> I was watching Red Bull on the w/e and noticed all aircraft had
>>> three bladed props.
>>>
>>> It got me wondering - what are the pros and cons of multi-bladed
>>> props. Yeah, I know two bladed are multi but I mean greater than
>>> two. The Spitfire at the aircraft museum has a five bladed prop.
>>>
>>> Are they more efficient? Is the drag created, offset by the increased
>>> efficiency (pretty obvious otherwise the wouldn't have more than two
>>> blades).
>>>
>>> cheers
>
>
>
> Ya know, Nick O' that in the US in the '50s, there was also an
> after-market ...
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Author: Nick O'TymeNick O'Tyme Date: Nov 5, 2007 04:39
> Nick O'Tyme wrote:
>
>> I was watching Red Bull on the w/e and noticed all aircraft had three
>> bladed props.
>>
>> It got me wondering - what are the pros and cons of multi-bladed props.
>> Yeah, I know two bladed are multi but I mean greater than two. The
>> Spitfire at the aircraft museum has a five bladed prop.
>>
>> Are they more efficient? Is the drag created, offset by the increased
>> efficiency (pretty obvious otherwise the wouldn't have more than two
>> blades).
>>
>> cheers
>
> The horsepower that can be absorbed by a propeller is dictated by the
> blade
> area and rpm (higher rpm, less area needed). No problem for low powers, ...
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Author: Nick O'TymeNick O'Tyme Date: Nov 5, 2007 04:42
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Author: Nick O'TymeNick O'Tyme Date: Nov 5, 2007 04:44
"Stealth Pilot" aeroplanes.com.au> wrote in message
news:h2pti39fpkrubq3lt2qo2ur6ltp4v85ug2@4ax.com...> On Mon, 05 Nov 2007 20:14:25 +1100, JD spamlesstpgi.com.au>
> wrote:
>>>Nick O'Tyme wrote:
>>
>>> I was watching Red Bull on the w/e and noticed all aircraft had three
>>> bladed props.
>>>
>>> It got me wondering - what are the pros and cons of multi-bladed props.
>>> Yeah, I know two bladed are multi but I mean greater than two. The
>>> Spitfire at the aircraft museum has a five bladed prop.
>>>
>>> Are they more efficient? Is the drag created, offset by the increased
>>> efficiency (pretty obvious otherwise the wouldn't have more than two
>>> blades).
>>>
>>> cheers
>> ...
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