Acceleration comparisons

[majorfailure]

Originally Posted by horseback

Notes on USN/USMC Fighters tested @ 5K ft.

1. The early Wildcats seem to compare with what I know of their performance, not spectacular but stable; however, the FM-2, which was 500 lbs lighter & somewhat aerodynamically cleaner than the F4F-4, as well as enjoying a 160 hp power advantage at altitudes up to nearly 20,000 ft, is portrayed in-game as even more sluggish than its predecessors. I was so surprised by this, I ended up re-running the FM-2 to ensure that I hadn't left the landing gear hanging down or something, but it was just as sluggish and 'meh' as the first time. Historically, this was simply not the case. The FM-2 was widely acknowledged as the 'wilder' Wildcat; being lighter, cleaner and more powerful at low and medium altitudes, it had superior climb and acceleration, and a somewhat better top speed at low and medium altitudes. It was a much better match for the Zero, even the later models. Someone's got some 'splaining to do.

Again: Just because an an engine model does more hp at some alt, it does not mean it does more hp at any alt. 5kft is near FTH of first stage of F4F -good alt for it. Try at 5km alt - FM-2 will be better than F4F.

Originally Posted by horseback

3. Both models of Hellcat continue to be a huge letdown. With or without water injection, it is portrayed as a slug, and much slower than the official numbers I have found. A standard F6F-3 should be capable of 290 kts/330 mph true airspeed, or about 530 kph at this altitude. If the Wonder Woman 'speedometer' is correct, that would mean an IAS of about 470/480 kph in-game. The best level TAS I got from the F6F-3 was just over 510 kph, and the best level TAS on the F6F-5 was around 515 kph, or about 460 kph indicated for both. Again, there was very little difference in acceleration between the two, in spite of the extra 200 hp or so that the water injection of the Dash 5 is supposed to have. Again, I re-ran the Dash 5 to make sure that I hadn't done something wrong. The main difference is in top speed, but from 270 to 380 IAS indicated, there is no difference.

cheers

horseback

At http://www.wwiiaircraftperformance.org/f6f/f6f.html I can find only 315mph at 5kft for an F6F-3 without water injection. Other tests are either with water injection, do not cover that alt or are not fully loaded fighters.

http://www.wwiiaircraftperformance.o...6f-3-02982.pdf
is interesting because it states that early F6Fs were problematic to rudder trim in a power climb.

[MaxGunz]

Water injection in game is with WEP?

[jameson]

"There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power."
JtD, lol. Try it ingame and let us know how fast you can get it, 480? if that? At 110% I get sometimes 520ish...
A minute of climb at 110% in a fight can be an awfully long time and would be even better if ingame matched RL "historical" peformance. If it did there'd also be more grunt throughout the power curve ingame. Takeoffs would start to get very interesting with correctly modelled torque. Forget to lock the tail wheel in RL and the rudder couldn't stop it making a left turn, with usually fatal results... Ingame?
Gunz I believe that WEP is water injection, it may be in the manual, been a while though since I read it.

[JtD]

Originally Posted by jameson

"There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power."
JtD, lol.

I was confirming what you said right there, but if you think you need to laugh about it, so be it.

[horseback]

Originally Posted by jameson

"There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power."
JtD, lol. Try it ingame and let us know how fast you can get it, 480? if that? At 110% I get sometimes 520ish...
A minute of climb at 110% in a fight can be an awfully long time and would be even better if ingame matched RL "historical" peformance. If it did there'd also be more grunt throughout the power curve ingame. Takeoffs would start to get very interesting with correctly modelled torque. Forget to lock the tail wheel in RL and the rudder couldn't stop it making a left turn, with usually fatal results... Ingame?
Gunz I believe that WEP is water injection, it may be in the manual, been a while though since I read it.

Try closing your radiators at about the time you hit 450 kph indicated; it will bump up your top speed and final stages of acceleration a bit, as long as you count to about 30 seconds or so after the overheat message pops up and then open them up and slow down.

I can't imagine adding RL levels of torque in the game at this point in its life; the 109 and P-40 would become almost impossible, never mind 'interesting', to land or take off for the vast majority of players.

Personally, I already have a full 'whine' cellar.

cheers

horseback

[MaxGunz]

Originally Posted by horseback

I can't imagine adding RL levels of torque in the game at this point in its life; the 109 and P-40 would become almost impossible, never mind 'interesting', to land or take off for the vast majority of players.

That's low speed nose high propwash. Use rudder, not side stick. Keep the prop revs high and power low in case you have to go around.

Funny thing how I read from guys allowed to try out a 109 because they qualify and still going off the strip just trying to take off the first time.

[horseback]

Originally Posted by majorfailure

Again: Just because an an engine model does more hp at some alt, it does not mean it does more hp at any alt. 5kft is near FTH of first stage of F4F -good alt for it. Try at 5km alt - FM-2 will be better than F4F.

Every source I have shows the FM-2 superior to the F4F-3/4 up to around 18-20,000 ft. The same site you link has tests for both which indicates that the FM-2 at 5K will do a bit over 310mph, or within an eyelash of 500kph; the F4F-4 at 4500 ft is listed at 283 mph or 455 kph, a difference I consider significant.

At http://www.wwiiaircraftperformance.org/f6f/f6f.html I can find only 315mph at 5kft for an F6F-3 without water injection. Other tests are either with water injection, do not cover that alt or are not fully loaded fighters.

I can't find much mention whether the engine was a plain vanilla -8 or -10, or a -8W or -10W, which indicates water injection, but it was not always noted back then. That still leaves the questionable performance of the F6F-5, which should do at least 330 mph at that altitude, or about 15-20 kph more than I could get in seven test runs.

http://www.wwiiaircraftperformance.o...6f-3-02982.pdf
is interesting because it states that early F6Fs were problematic to rudder trim in a power climb.

I don't know if you're a native English speaker, major, but we refer to this sort of thing as "cherry picking." I'm sure you'll find it a useful term.

Like many high performance fighters, the rudder corrections for extreme changes in speed (as experienced in a sudden climb or dive) could not be rolled in quickly enough on the Hellcat, sometimes requiring the pilot to exert pressure on the rudder pedals; the same phenomenon was noted for the P-40, P-47, P-51 and the Corsair to some degree, much greater in the case of the P-40 (meaning that the Warhawk was a couple of orders of magnitude worse than the Hellcat), about the same as in the P-47 and less in the other types. If the rudder issues you refer to consist of the notation on page 8, it was a minor issue and quite acceptable (and clearly superior to the rudder input demands placed on a pilot flying a Bf 109 or FW 190). AFAIK, it was common to all models of the Hellcat, and considered a fairly mild vice.

Edit: The reason it was mentioned is that the original contract probably specified that rudder forces would be trimmable throughout the aircraft's performance (I'd have to re-read Tillman's book to be sure); this turned out to be impossible with the engine and propeller changes from the original R-2600 and Curtiss Electric combination envisioned for the Hellcat, so it was just noted and signed off on every acceptance test rather than go to the massively complicated task of revising all the contract documents in the possession of Grumman and the Navy Department (this was the age of hand-typed documents and carbon copies, remember; they hired thousands of young women to type and file and keep track of all the hard copies, and had warehouses full of the original documents) and getting them re-signed. I can tell you from personal experience that some government contracts still get this sort of standard waiver treatment for minor issues and that if the government rep who had to inspect the paperwork was transferred, you'd better be able to produce the original paper trail for his or her replacement.

cheers

horseback

[majorfailure]

Originally Posted by horseback

I can't find much mention whether the engine was a plain vanilla -8 or -10, or a -8W or -10W, which indicates water injection, but it was not always noted back then. That still leaves the questionable performance of the F6F-5, which should do at least 330 mph at that altitude, or about 15-20 kph more than I could get in seven test runs.

Most test documents state the engine the plane was equipped, if not usually it can be deduced from loadout given, there is some amount (16gallons?) of anti-detonant mentioned when water injection was used.

The document above states: "Rudder trim effectiveness was not sufficient to trim in the high power climb." If I get this correctly it means though FULL rudder trim was applied in a high power climb the plane still deviated from flying straight. So at least early F6F-3s were trim hogs in rudder when climbing with full power - and I doubt that later model F6F behaved much different - even if a larger trim tab or different rudder were added, changing from clevel flight to climb would still require lots of trim change in rudder.

Water injection does "move" the power curve towards more power AND towards lower alt. So while the F6F-3 will be faster with first stage of the charger at 5kft (FTH~1000m), the F6F-5 will be faster when water injection is engaged in the second stage at that alt.
Same for the Corsairs: F4U-1 in first stage and F4U-1A in second stage when using WI above~1000m.
Water injection will work and will use water/methanol mix in first stage though, BUT will not have much of an effect.

Just compare the two power curves of the F6F-3(without WI) and and the F6F-5 in IL2compare. (Or F4U-1//F4U-1a)

[jameson]

Horseback, thanks for the effort you've put into this thread and my apologies for hijacking it somewhat. Your suggestion regarding 109 radiators is noted and I'll give it a go. In RL according to Finnish 109 pilots. the effect on speed was pretty minimal to the point of not being noticed, whether rads were open or closed. If 109G6's ever get an fm makeover perhaps this'll get fixed as well.
There was a very early mod from the AAA days which did up the torque effects for the 109, how accurate it was I couldn't say, but slamming the throttle to the wall at take off wasn't wise as it did have a gap where the rudder was non resposive and if the tail was lifted too early it got a bit tense!