Seafire FR 47 and Griffon engine Incorrect Performance Discussion

Machinery of War Discussion Aircraft
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This is an issue I am relatively new to, but I have done a bit of research. Seafire FR 47’s Griffon 88 engine is clearly underperforming, as it’s running at 21 lb boost(~2.42 ata) with 150 octane fuel, same as the Spitfire Mk 24, when it never ran this setting, and with 150 octane fuel should be running 25 lb boost(~2.7 ata), and producing 2350-2400 horsepower.

I’ve looked through the prior bug reports on this issue, and found that a number have been rejected for only having 1 acceptable source, such as this one.

However through this I have managed to accumulate 3 “secondary sources” which were all also at some point or other deemed acceptable by Gaijin, that show the Seafire FR 47 and/or Griffon 88 engine running 25 lb of boost with 2300-2400 hp.

Unfortunately the Spitfire’s technical/user manuals only show data for 18 lb of boost with 130 octane fuel, so as far as I am aware there is no “primary source” in existence for the 25 lb boost with 150 octane fuel. In one of the previously rejected bug reports I found, it was stated by Gaijin “This aircraft (model) is flying within the correct limits outlined in the Pilot’s Notes for Supermarine Seafire FR 47 (Air Publication 2280H-P.N.)”. But the Pilot’s Notes for the Seafire FR 47 doesn’t state ANYTHING about the boost with 150 octane fuel, it ONLY provides information for hp with 18 lb of boost with 130 octane fuel. This is the same with manuals I have seen for other Griffon spitfires as well, data is for 100/130 octane fuel only.

So it seems Gaijin does not actually have any primary source for their implementation of 150 octane fuel on the Seafire FR 47, and so I can only assume they have chosen to just copy-paste how they’ve implemented it on the Mk 24 in an ahistorical manner and ignore all the secondary sources. However, the Spitfire Mk 24 should also be capable of running 25 lb of boost with its 150 octane fuel, and the Spitfire Mk 14 and Mk 22 should be able to run 21 lb of boost with 150 octane fuel, if they had it, which is not the case ingame but was used IRL.

Incredibly, so far the only reason I have managed to find that all of these Griffon spits are running sub-optimal boost settings is because way back in the day, it was Gaijin’s opinion that they would be too unbalanced at the time.

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EDIT:
https://www.baesystems.com/en-uk/heritage/vickers-supermarine-seafire
https://drive.google.com/file/d/1cC6Krhu27kl7FJgY-ji7TBfvuhBJgLsX/view
http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Griffon.pdf

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https://community.gaijin.net/issues/p/warthunder/i/c18QFryvjTGn
There is this report.

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Hello,

I made the bug report @Fireball_2020 mentioned.

I have been looking into the Griffons for a good while now after reading that post-war tests found the MK.XIV to be the best dogfighter of the war despite in war thunder the LF MK.IX handily beats it.

For the FR 47:

Firstly you may find this griffon engine PDF useful: http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Griffon.pdf

Here is one particular extract for you, You will notice at the bottom is specifically mentions 25.0lbs boost.

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From what I can tell almost all Griffon engines are capable of 150 Octane and Uprating to 25 PSI/Lbs Boost. Additionally it seems every engine running less that 150 octane fuel also ran around 18 PSI and that with the upgrade to 150 Octane came an uprating to 21 or later on 25 PSI Boost.

The engines are originally rated for 130 Octane as that was deemed the best compromise between availability and performance.

For the MK.14, 22 and 24:

These ones I am more sure on, my bug report here shows that the Mk.14e can be uprated to at least 21 PSI boost and indeed this was service standard during mid-1944-1945, when it was then further increased to 25 PSI. The MK.22 engine for WT purposes can be considered to have the exact same limitations and boost presents but with generally higher output. The MK.24 should almost certainly be running 25lbs as I believe it always ran 25lbs as a carry over modification from the MK.22’s they were partly converted from.

Also worth noting: The Boost curves for these spitfires do not seem to be correct, ingame they spike at their boost rating and then seem to lower and settle below, when they should spike higher than their boost rating before settling on their actual rating depending on the altitude, simply put you don’t get as much hp as you should.

Another thing, the radiators produce too much drag (I think) and do not seem to have the Meredith effect modelled such as is present on P-51’s and I believe certain Yak models. I am still looking for sources to see if any spitfire was tested with radiators open so I can make a wider report regarding meredith effect and its implementation on spits.

Finally, the aircraft should all be able to WEP for 6 minutes from 100% power before the engine starts to risk permanent damage and only then should the radiators begin to deploy if I am interpreting correctly.

My Solution

Spitfire MK.14e received 150 Octane and increase to 21 lbs boost.

Spitfire MK.22 receives 150 Octane, 21 lbs boost and a br decrease to 6.3

Spitfire MK.24 receives uprating to 25 lbs boost rather than the ~20 it seems to sit at.

FR.47 Increased in boost rating and maintains its br.

Apologies this is so long. Let me know if I can do anything to help you.

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Hey if you do the report hit me up.
I can forward it as a suggestion with those 3 secondary sources like the one @Rileyy3437 included, no problem.

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Thanks for your response and for making that bug report, I really hope they listen to it. When I made this post I was hoping that people more familiar with the topic and with more info would reply since I only recently started looking into this. Your report seems to make use of a lot of sources I didn’t know of. Aircraft Engines of the World was one of the 3 sources I mentioned that I found.

There are some other quirks with the FR 47 in particular that I noticed but I don’t have any historical information or sources on them. It’s running at the same boost as the Mk 24, but it has so much more drag that it’s speed is more comparable to the Mk 22. I don’t know where all this drag comes from since they are aerodynamically quite similar. The landing gear bulges are slightly bigger, the intake is longer, and it has a tailhook, but I can’t see this reducing speed so massively.

Additionally, It’s my understanding that contra-rotating propellers tend to have noticeably superior prop efficiency, yet ingame the FR 47’s prop and the Mk 24’s are identically efficient. This and the drag make me think that the FR 47 should be comparable or maybe even faster than the Mk24, not massively slower as it is. I don’t have sources for these things so I could be wrong, and I wouldn’t be able to substantiate it for a bug report.

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For a simpleton, what would that do for flight performance? Give a bit more engine power across the board, so better accel, climb rate etc?

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In a nutshell: yes.

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Thats a slight, understatement, but other than that yes.

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For most of them its a pretty significant upgrade for anything engine related. Power to weight will increase so you climb better and prophang longer, you will also be significantly faster, accelerate faster and retain more energy as you are generating more.

Things like the MK.XIV will be less of an obvious downgrade to others like the LF MK.IX which produces more power than it because though it won’t turn as well, it will be significantly faster

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Lmao - seriously???

A 1948 production aircraft like the FR 47 with 2.400 hp at 5.7???

Put the the BR to the production year - we talk then about 7.3-7.7…Same with the post-war Mk 24 - the lower BR of 6.7 was just a panic attack of gaijin due to the MiG 15 / F-86 downtiering…

The only thing what makes sense in this thread is asking for implementing the correct engine performance, but without a realistic BR setting process (and increasing the BRs thx to way better performance) this makes zero sense and simply sound just like a wet dream of some UK fan boys.

I mean UK pilots are on average & for years way better than US or USSR players - there is simply no need to get more performance out of already good planes (without paying for it via a higher BR) - no need for undertiered / overperforming post-war trash like P-51 H-5, F2G or Yak 3U…

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that’ll presumably be why we haven’t got it then lmao

jeez, Snail when?

I mean yes, yes it is in my case, but my justification is to make up for the utter disappointment that is everything (or isn’t, CVRT when) in the damn tree lmao

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Interestingly my only book on the topic doesn’t mention an 25lb boost but the standard +18lb boost with a horsepower of 2.350hp for the Griffon 87/88
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I don’'t think basing BR off of production year makes any sense, nor does Gaijin’s current method of basing it off of player statistics. Actual flight performance of the aircraft is what really matters. It’s true that as a general trend later aircraft have better performance, but again this is just a trend and not a linear progression. The Ki-100 began production and service in 1945, this doesn’t mean it would be fair to place it at the same BR as the P-51H.

The Seafire FR 47 with it’s current performance at 5.7 is not particularly impressive compared with other post-WW2 superprops in any regard, and even with 2400 hp, that’s not likely to be reversed as it’s still ~700 kg heavier than the f24, which is itself heavier than the P-51H. Perhaps a small BR increase may or may not be in order. The plane is currently totally outclassed by other Spitfires and other nations aircraft at 5.7, it’s not unplayable it’s just worse than every alternative. The plane in it’s current state doesn’t belong at 5.7. I don’t think there is any way the FR 47 could be made worthy of say, 6.3 BR without massively unhistorical improvements. It’s climb, turn, and acceleration are always going to be worse than other griffon spits.

The P-51H is superior to the Spitfire Mk 24, or any other Spitfire or Seafire currently ingame, and depending how you look at it, it’s by a pretty wide margin. It’s just as you say, massively undertiered due to horrific performance of US players. The P-51H has more horsepower(2300), less weight, and drastically less drag due to superior aerodynamics compared to the Mk 24, which means it climbs better and is substantially faster at all altitudes, especially lower ones. The current Mk 24 isn’t even what would be considered fast for a superprop at low alt, it’s top speed at and around sea level is comparable to many fast WW2 serving 5.0-5.7 planes such as the P-51D-30, Tempest Mk V, and Fw 190 D-9. The P-51H by comparison is the fastest prop in the game at all altitudes anyone ever plays at, and is 30-40 MPH faster than the Mk 24 in level flight at low and medium alt. And this is the Mk 24, no other Spitfire or Seafire comes close to even that. The FR 47 and Mk 22 are more like 60 MPH slower than the P-51H, and will never get within 20-30 MPH of it even at high alt. F2G, F8F, and F4U-4B all dust any current spitfire or seafire variant at low alt.

The main thing Spitfires have over a P-51H or other US aircraft is that they turn well(except for the FR 47), which is the bane of US players mental capacity. Honestly I’d say the Spitfire Mk 22 and Mk 24 have a bit of A6M5 syndrome, since they are slower than other superprops and especially than jets, but turn really well and everyone is too stupid to not turn with them. The Mk 24 and especially the Mk 22 do not really deserve to be at 6.7 with their current performance, while the P-51H is the one that should be at 6.7 or 7.0.

I think Riley’s proposal sounds pretty reasonable, with 2400 hp then I think the Mk 24 would deserve it’s BR(or an increase back to 7.0), and with 21 lb of boost, the Mk 22 would perform similarly to how the Mk 24 currently does and go down to 6.3, where it would still be slower than most planes around its own BR but turn and climb well. If the FR 47 keeps its current level of drag and prop efficiency but receives 25 lb of boost, it would have speed comparable to the current Mk 24/changed Mk 22, but with much worse turn, climb and acceleration, making it actually comparable all-around to other fast props at 5.7. If it does too well down there it could go up to 6.0, but any higher would be unreasonable.

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Could you post the sources you used for the bug report? Im writing a bug report specifically for the Mk.24 and was wondering if you had the source showing the Griffon-66 could do 25 pounds of boost. Thanks.

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My apologies for not replying sooner, if im being honest I bookmarked this and then forgot to check my bookmarks.

Sources were this one about the specific engine marks

http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Griffon.pdf

This one about the engine in general

http://www.spitfireperformance.com/RR-Griffon.pdf

And then another about the MK.xiv specifically

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Ok thanks. I was looking for a source on the spitfire mk 24 getting hispano mk v’s. Thank you for the sources.

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Spitfire MK.24’s did use Hispano V’s which it has in-game. IIRC they started with the short barrelled ones and then got long-barrels later on.

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On the Griffon topic (I’m assuming you mean Griffon 61 as the MK.24 uses the 61 and not the 66), virtually every Griffon engine can do 18, 21 or 25 PSI boost. You shouldn’t need too much to get that report acknowledged as that’s just commonly accepted as a fact.

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it has mk 2 in game, which often leads to targets passing through your shots.

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Your report covers the engine. I was looking mainly for information to get the guns changes to Hispano mk v’s

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