Fairey Firefly Performance - Sea Level vs at altitude.

[Freebird]

Reading through the Armoured A/C website, it lists the Firefly as especially optimized for low level performance.
But it has a higher Sea Level speed than at 3,500 feet?
Is that possible?

Speed

In a clean configuration, the Firefly was rated as achieving 284mph at sea level, 273mph at 3500ft, and 319mph at 17,000ft

Armoured Aircraft Carriers

Apologies to Greyman, I borrowed your graph and added the Firefly.

Quick sketch on speeds.

Fulmar I - Fulmar II - Sea Hurricane I - A6M2

View attachment 531197

Fulmars are from the A&AEE, Sea Hurricane is from official data points from somewhere ... MAP I believe. A6M2 is from http://www.wwiiaircraftperformance.org/japan/intelsum85-dec42.pdf

 

[Greyman]

Two-speed engine. More like this:

 

[Freebird]

Two-speed engine. More like this:

View attachment 580238

Thanks for the clarification!

If we were to compare it to the F4F-4 Wildcat and the Seafire (mid '42 to early 1943) how would they compare on your graph?

Are Parsifal's numbers in this post correct?
Fulmar II versus F4F-4 under 10,000 ft.


Also, does your graph in these threads represent Seafire or only the land Spitfire?

Fulmar II versus F4F-4 under 10,000 ft.
P-39 vs P-40

 

[RCAFson]

Thanks for the clarification!

If we were to compare it to the F4F-4 Wildcat and the Seafire (mid '42 to early 1943) how would they compare on your graph?

Are Parsifal's numbers in this post correct?
Fulmar II versus F4F-4 under 10,000 ft.


Also, does your graph in these threads represent Seafire or only the land Spitfire?

Fulmar II versus F4F-4 under 10,000 ft.
P-39 vs P-40

Martlet II was 293 at 5400 and 293mph at 13800 ft
Martlet IV was 278 at 3400ft and 298 mph (F4F-4B) at 14600ft.

Comparative testing of the F4F-4, showed the F4F-4B to be slightly faster at low altitudes and slightly slower above 15000ft:
http://www.wwiiaircraftperformance.org/f4f/f4f-4-02135.pdf

This is the speed power curve for a Seafire LIIC:

and a Seafire IIC with a Merlin 45 Merlin 46 would be about ~10mph slower at low altitude, using 16lb boost but somewhat faster at higher altitude:

http://www.spitfireperformance.com/seafireIIc.pdf

in the above test boost was limited to 9lb.

 

[Greyman]

Previous graphs are for Spitfires not Seafires. Though nowadays I think the Spit V Merlin 46 figures I was using were off -- and it should be about 10mph slower.

Orange lines are different figures for Firefly I
Thick red line is my rough +16 boost estimate on the Seafire IIc (Merlin 46) test RCAFson linked
Thin red line is a rough trace of the Seafire IIc (Merlin 32) graph posted
Thick black line is the Seafire III (Merlin 55)
Thin black line is my estimate on a BPF Seafire III (ejector exhausts, no snow guard)

 

[Freebird]

Previous graphs are for Spitfires not Seafires. Though nowadays I think the Spit V Merlin 46 figures I was using were off -- and it should be about 10mph slower.


Orange lines are different figures for Firefly I
Thick red line is my rough +16 boost estimate on the Seafire IIc (Merlin 46) test RCAFson linked
Thin red line is a rough trace of the Seafire IIc (Merlin 32) graph posted
Thick black line is the Seafire III (Merlin 55)
Thin black line is my estimate on a BPF Seafire III (ejector exhausts, no snow guard)

Where did you get the data for the Firefly?

 

[tomo pauk]

Reading through the Armoured A/C website, it lists the Firefly as especially optimized for low level performance.
But it has a higher Sea Level speed than at 3,500 feet?
Is that possible?

It is very much possible, since the Firefly was not optimized (whether 'especially' or not) for performance at any altitude.

 

[Greyman]

Where did you get the data for the Firefly?

A&AEE test (thick line) and MAP data sheet (curve of former placed on the two max speed points given)

 

[Freebird]

It is very much possible, since the Firefly was not optimized (whether 'especially' or not) for performance at any altitude.

???
Well let's see, it is faster at low altitude and turns quicker than an A6M or an F4F-4, so I'd be pretty pleased with that performance.
Of course if the Japanese torpedo bombers could drop their fish from 12,000+ feet then the Firefly would be at a disadvantage...

 

[tomo pauk]

???
Well let's see, it is faster at low altitude and turns quicker than an A6M or an F4F-4, so I'd be pretty pleased with that performance.

It might be as well that it was just a bit faster than F4F-4. Being a 2 year later aircraft, that is not something that we should applaud immediately. Compared with FM-2, that entered service a few moths later than Firelfy, the later was slower. It was also slower than A6M5, the model of same vintage, and barely faster than Zeros of 1942.
Once we take a look at other Allied carrier-borne fighters in service by winter of 1943-44, Firefly has a performance disadvantage vs. Sea Hurricane, Seafire, F6F, F4U. At any altitude.
Why would anyone go into a turning fight if it does not have to do it?

Of course if the Japanese torpedo bombers could drop their fish from 12,000+ feet then the Firefly would be at a disadvantage...

Japanese dive bombers by winter of 1943/44 were faster than Firefly. So were the land-based 2-engined bombers.

 

[Freebird]

A&AEE test (thick line) and MAP data sheet (curve of former placed on the two max speed points given)

Is the A&AEE test linked online somewhere?
There's most of the aircraft data linked here, but not the Firefly.
WWII Aircraft Performance

 

[CORSNING]

The following performance graphs were provided by Mr. Neil Stirling.





Thank you Neil, Jeff

 

[Laurelix]

If I'm not mistaken

Fairey Firefly Mk V
483km/h at SL
554km/h at 5200m

 

[RW Mk. III]

It might be as well that it was just a bit faster than F4F-4. Being a 2 year later aircraft, that is not something that we should applaud immediately. Compared with FM-2, that entered service a few moths later than Firelfy, the later was slower. It was also slower than A6M5, the model of same vintage, and barely faster than Zeros of 1942.
Once we take a look at other Allied carrier-borne fighters in service by winter of 1943-44, Firefly has a performance disadvantage vs. Sea Hurricane, Seafire, F6F, F4U. At any altitude.
Why would anyone go into a turning fight if it does not have to do it?



Japanese dive bombers by winter of 1943/44 were faster than Firefly. So were the land-based 2-engined bombers.

I would opine that the performance for the firefly was quite good for a two-seat dayfighter. The problem isn't the performance. The problem is that two-seat dayfighters are a bit mad in the time and role the firefly occupied. I think the conversation will always end up there. The problem is intrinsically the concept and not the execution. Execution could have been quicker off the line certainly, but the aircraft itself was quite good in a lot of ways.

 

[tomo pauk]

I would opine that the performance for the firefly was quite good for a two-seat dayfighter. The problem isn't the performance. The problem is that two-seat dayfighters are a bit mad in the time and role the firefly occupied.

Performance (or the lack of it) is/was the problem. Job of a fighter is to catch the enemy bomber and recon aircraft and shoot them down, while at least holding it's own against the enemy opposition of the same generation. Firefly could not do any of that in a reliable fashion.

I think the conversation will always end up there. The problem is intrinsically the concept and not the execution. Execution could have been quicker off the line certainly, but the aircraft itself was quite good in a lot of ways.

Firefly was probably a good aircraft, when not doing the fighter job. Concept might've been wrong, execution didn't brought any new technology nor a jump in performance.

 

[RCAFson]

I would opine that the performance for the firefly was quite good for a two-seat dayfighter. The problem isn't the performance. The problem is that two-seat dayfighters are a bit mad in the time and role the firefly occupied. I think the conversation will always end up there. The problem is intrinsically the concept and not the execution. Execution could have been quicker off the line certainly, but the aircraft itself was quite good in a lot of ways.

I don't agree. The Firefly and Fulmar were designed pre-radar when pilot workload was very high and these aircraft were also intended for recon and divebomber/strike roles. The Fulmar had strike capability removed to speed development and it wasn't put back until just before they were withdrawn from front line service. The basic problem with Firefly performance was not the 2nd seat, but the lack of engine power at only 1730hp - it didn't reach ~2000hp (When Griffon boost was increased from 12lb to 15lb and the 1990hp Griffon XII introduced) until late 1944/early 45. Performance figures for the Firefly 1 seem to be based upon the initial rating of the Griffon IIB.

The Firefly is actually about the same weight as the F6F or F4U.

 

[RCAFson]

https://ww2aircraft.net/forum/attachments/img_0525-jpg.496106/

??????

This is what I see:

You do not have permission to view this page or perform this action.

 

[CORSNING]

Mr. Neil Stirling sent this information to me in a PM. I have sent him a
PM asking him to post this information himself. I cannot speak for Mr.
Stirling. Either way, he will let me know when he is able.

 

[RCAFson]

https://ww2aircraft.net/forum/attachments/img_0526-jpg.496108/

When I try and view the attachment I get the same result:

"Oops! We ran into some problems.
You do not have permission to view this page or perform this action."

 

[DerAdlerIstGelandet]

We will look into it.