Performance growth of the Spitfire with contra-rotating propellers

[spicmart]

Can anyone give performance stats of the Spitfire Mk.22, which featured a contra-rotating prop, compared to its Seafire equivalent Mk.46 which had a normal 5-bladed prop.
Or alternatively to the Mk.21 for that matter, which differed only by its normal raised back and which might be close enough performance-wise.

 

[MikeMeech]

Can anyone give performance stats of the Spitfire Mk.22, which featured a contra-rotating prop, compared to its Seafire equivalent Mk.46 which had a normal 5-bladed prop.
Or alternatively to the Mk.21 for that matter, which differed only by its normal raised back and which might be close enough performance-wise.

Hi
probably not what you require, but Alfred Price's 'The Spitfire Story', p.248, has the following test report on the Spitfire F.21 fitted with a contra-rotating propeller:

Mike

 

[spicmart]

Hi
probably not what you require, but Alfred Price's 'The Spitfire Story', p.248, has the following test report on the Spitfire F.21 fitted with a contra-rotating propeller:
View attachment 823125
Mike

Very Interesting nonetheless!

 

[Greyman]

I see the data card at WWII Aircraft Performance

 

[Delft]

Can anyone give performance stats of the Spitfire Mk.22, which featured a contra-rotating prop, compared to its Seafire equivalent Mk.46 which had a normal 5-bladed prop.
Or alternatively to the Mk.21 for that matter, which differed only by its normal raised back and which might be close enough performance-wise.

Spitfire Mk 22 in production format didnt have contra-props. Best comparison would be Seafire 46 with Seafire 47 ... the Seafire Mk 47 was the only production version of the Spitfire/Seafire lineage to have contra props.
Try Tony Butlers book "Propellor Twightlight" for further details.

 

[Jabberwocky]

Some quotes from Peter Caygill in Ultimate Spitfire (pp 60-61) on the five-bladed F.21 vs a pair of contra-prop fitted aircraft. 71 hours of trials were flown by the ADFS [formerly the ADFU] at Tangmere in 1945.


Both aircraft [LA215 and LA217] were identical to the normal Spitfire F.21 except for the contra-prop mechanism which reduced the maximum power available by some 135 hp.

...

As the aircraft did not have the enlarged tail a speed limitation of 470 mph was imposed in view of the destabilising effect of the contra-prop at high speed. Longitudinal stability showed a definite improvement over the standards five-bladed F.21 and the aircraft was stable fore-and-aft at all speeds from 125-450 IAS at low to medium altitudes and at 30,000 ft down to 140 mph IAS. There was no tendency to tighten up in turns, although the aircraft could be easily held in the turn with light stick forces.

...

In terms of lateral stability the contra-prop had no effect, the aircraft being just stable in the rolling plane at low altitude and just unstable above 30,000 ft. The ailerons were light and effective over the whole speed range.

...

All forms of aerobatics were greatly enhanced by the contra-prop due to the complete absence of change of directional trim with speed or throttle setting and a uniform rate of roll in either directions. It was noted, however, that the height at which the climb rate fell below 1,000 ft/min was 4,000 ft below that for a standard F.21 which was due mainly to the reduced diameter of the propeller. Pilots were unanimous in their praise for the contra-prop F.21 as a sighting platform for air-to-air and air-to-ground firing due to the lack of skid and it was easy to hold the sight on another aircraft, even if it took violent evasive action.

...

For all practicable purposes the aircraft [standard and contra-prop fitted] were identical in terms of speed up to their operational ceilings, although the standard aircraft had slightly better acceleration, particularly at low speed. Climb performance on the contra-prop F.21 was also not as good, the climb rate being around 100 ft/min less at sea level and 300 ft/min less at 21,500 ft.

...

Zoom climbs showed no appreciable difference, although the standard aircraft appeared to have a slight advantage below 300 mph IAS, the contra-prop F.21 being superior above this. The most significant advantage for the latter was a better rate of turn, particularly at high altitude and in turns to the left, the improved 'feel' of the aircraft being most marked when carrying out tight turns.