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View Full Version : Winter Flying, pt 3 - Lighting Ski.jpg (1/1)


Mitchell Holman[_2_]
February 1st 07, 01:35 PM

Art Woodbury[_1_]
February 2nd 07, 12:12 AM
In article >,
says...
>
> begin 644 Lighting Ski.jpg

I posted recently on this subject. Does anyone know why
Lightnings had the contra-rotating props on the "wrong"
sides? P-factor and torque from the outward-turning props
make both sides critical in an engine-out situation. Kelly
Johnson didn't make mistakes like this. Is there an
explanation?

Art W.

Art Woodbury[_1_]
February 2nd 07, 12:12 AM
In article >,
says...
>
> begin 644 Lighting Ski.jpg

I posted recently on this subject. Does anyone know why
Lightnings had the contra-rotating props on the "wrong"
sides? P-factor and torque from the outward-turning props
make both sides critical in an engine-out situation. Kelly
Johnson didn't make mistakes like this. Is there an
explanation?

Art W.

Frank from Deeeetroit
February 3rd 07, 04:17 PM
"Art Woodbury" > wrote in message
.. .
> In article >,
> says...
>>
>> begin 644 Lighting Ski.jpg
>
> I posted recently on this subject. Does anyone know why
> Lightnings had the contra-rotating props on the "wrong"
> sides? P-factor and torque from the outward-turning props
> make both sides critical in an engine-out situation. Kelly
> Johnson didn't make mistakes like this. Is there an
> explanation?
>
> Art W.

To balence out the torque generated by the two engines.

Frank from Deeeetroit
February 3rd 07, 04:17 PM
"Art Woodbury" > wrote in message
.. .
> In article >,
> says...
>>
>> begin 644 Lighting Ski.jpg
>
> I posted recently on this subject. Does anyone know why
> Lightnings had the contra-rotating props on the "wrong"
> sides? P-factor and torque from the outward-turning props
> make both sides critical in an engine-out situation. Kelly
> Johnson didn't make mistakes like this. Is there an
> explanation?
>
> Art W.

To balence out the torque generated by the two engines.

Lynn in StLou
February 3rd 07, 06:40 PM
Frank from Deeeetroit wrote:
> "Art Woodbury" > wrote in message
> .. .
>> In article >,
>> says...
>>> begin 644 Lighting Ski.jpg
>> I posted recently on this subject. Does anyone know why
>> Lightnings had the contra-rotating props on the "wrong"
>> sides? P-factor and torque from the outward-turning props
>> make both sides critical in an engine-out situation. Kelly
>> Johnson didn't make mistakes like this. Is there an
>> explanation?
>>
>> Art W.
>
> To balence out the torque generated by the two engines.
>
>
Balancing the torque is correct. But, IIRC, they
originally rotated the opposite direction (facing
craft, top rotating in), and were changed to help
resolve a buffeting problem.

--
Lynn in StLou
REMOVETHIS anti-spam measure to reply

Lynn in StLou
February 3rd 07, 06:40 PM
Frank from Deeeetroit wrote:
> "Art Woodbury" > wrote in message
> .. .
>> In article >,
>> says...
>>> begin 644 Lighting Ski.jpg
>> I posted recently on this subject. Does anyone know why
>> Lightnings had the contra-rotating props on the "wrong"
>> sides? P-factor and torque from the outward-turning props
>> make both sides critical in an engine-out situation. Kelly
>> Johnson didn't make mistakes like this. Is there an
>> explanation?
>>
>> Art W.
>
> To balence out the torque generated by the two engines.
>
>
Balancing the torque is correct. But, IIRC, they
originally rotated the opposite direction (facing
craft, top rotating in), and were changed to help
resolve a buffeting problem.

--
Lynn in StLou
REMOVETHIS anti-spam measure to reply

Art Woodbury[_1_]
February 3rd 07, 09:39 PM
In article >,
says...
> Frank from Deeeetroit wrote:
> > "Art Woodbury" > wrote in message
> > .. .
> >> In article >,
> >> says...
> >>> begin 644 Lighting Ski.jpg
> >> I posted recently on this subject. Does anyone know why
> >> Lightnings had the contra-rotating props on the "wrong"
> >> sides? P-factor and torque from the outward-turning props
> >> make both sides critical in an engine-out situation. Kelly
> >> Johnson didn't make mistakes like this. Is there an
> >> explanation?
> >>
> >> Art W.
> >
> > To balence out the torque generated by the two engines.
> >
> >
> Balancing the torque is correct. But, IIRC, they
> originally rotated the opposite direction (facing
> craft, top rotating in), and were changed to help
> resolve a buffeting problem.
>
>
Balancing torque is helpful of course, but more important
is minimizing P-factor, where you can run out of rudder
authority sooner when the critical engine is out. Inward-
turning props would help that situation a lot.

Resolving a buffeting problem is certainly a reasonable
answer. I was sure there must have been an important reason
to sacrifice engine-out handling.

Art Woodbury[_1_]
February 3rd 07, 09:39 PM
In article >,
says...
> Frank from Deeeetroit wrote:
> > "Art Woodbury" > wrote in message
> > .. .
> >> In article >,
> >> says...
> >>> begin 644 Lighting Ski.jpg
> >> I posted recently on this subject. Does anyone know why
> >> Lightnings had the contra-rotating props on the "wrong"
> >> sides? P-factor and torque from the outward-turning props
> >> make both sides critical in an engine-out situation. Kelly
> >> Johnson didn't make mistakes like this. Is there an
> >> explanation?
> >>
> >> Art W.
> >
> > To balence out the torque generated by the two engines.
> >
> >
> Balancing the torque is correct. But, IIRC, they
> originally rotated the opposite direction (facing
> craft, top rotating in), and were changed to help
> resolve a buffeting problem.
>
>
Balancing torque is helpful of course, but more important
is minimizing P-factor, where you can run out of rudder
authority sooner when the critical engine is out. Inward-
turning props would help that situation a lot.

Resolving a buffeting problem is certainly a reasonable
answer. I was sure there must have been an important reason
to sacrifice engine-out handling.

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