Author Topic: Improve the P-47 (Read 11307 times)

Debonair · « **Reply #225 on:** November 06, 2006, 12:30:58 AM »

you forgot to add on the pro side for high weight: higher Va

Knegel · « **Reply #226 on:** November 07, 2006, 03:08:56 AM »

Hi,

Afaik there are different definations of the Va(manouvering speed).

1. maximum speed [at a particular weight] at which full deflection of the controls can be made without exceeding the design limit load factor and damaging the airplane’s primary structure” and Va is the maximum recommended speed for turbulent air penetration.

2. Va is the speed below which our aircraft will stall rather than bend or break.

Regarding 1. the weight is not direct related, rather the construction. Weight can be a indicator for a rough construction, but weight also stress the construction.

Regarding 2. a faster Va of course is a advantage, same like a higher stallspeed in general, but also this dont have to do with weight, rather with liftload and spanload etc.

What i forgot is the Vmax(dive), if the construction allow high mach numbers(in case of the P38 this dont seems to be always the case, so the high weight dont help here).

Greetings,

Knegel

Stoney74 · « **Reply #227 on:** November 07, 2006, 10:09:56 AM »

A 500 mph IAS Vne has to be reassuring.

Knegel · « **Reply #228 on:** November 07, 2006, 11:29:55 AM »

Quote

Originally posted by Knegel
Hi,

Afaik there are different definations of the Va(manouvering speed).

1. maximum speed [at a particular weight] at which full deflection of the controls can be made without exceeding the design limit load factor and damaging the airplane’s primary structure” and Va is the maximum recommended speed for turbulent air penetration.

2. Va is the speed below which our aircraft will stall rather than bend or break.

Regarding 1. the weight is not direct related, rather the construction. Weight can be a indicator for a rough construction, but weight also stress the construction.

Regarding 2. a faster Va of course is a advantage, same like a higher stallspeed in general, but also this dont have to do with weight, rather with liftload and spanload etc.

What i forgot is the Vmax(dive), if the construction allow high mach numbers(in case of the P38 this dont seems to be always the case, so the high weight dont help here).

Greetings,

Knegel

Just saw that i wrote advantage, where i was up to write disadvantage!

"Regarding 2. a faster Va of course is a disadvantage.............."

Stoney,

Vne of 500mph at what altitude??

Greetings,

Debonair · « **Reply #229 on:** November 07, 2006, 05:45:52 PM »

I've never seen a plane where the V speeds were given for specified altitudes, just always in IAS.
there is a pretty good reason for this...

Knegel · « **Reply #230 on:** November 08, 2006, 12:20:29 AM »

Hi,

planes that operate above 12000ft and above 250knots normaly get a list of IAS speeds, related to the altitude, simply cause the mach related problems, not the normal airflow turn to be the main problem regarding the Vne limit.

Though this problem get minimized a bit, cause the IAS measurement start to overrate, also cause mach related problems with the pitot tube. Therefor the planes might not fly as fast as the IAS indicate, but still the Vne IAS depents to the altitude.

I already saw some of this charts for WWII planes posted here on the board.

Normal modern Spotplanes and gliders only show 1 Vne IAS.

Greetings,

Knegel

Debonair · « **Reply #231 on:** November 08, 2006, 01:11:10 AM »

the good reason i mentioned, i've never flown anything faster than a bonanza or been over 11,500';)