View Full Version : My F4U wont go over 220mph in level flight

11-03-2004, 11:14 AM
What gives. help please

11-03-2004, 11:23 AM
check your landing gear and throttle axis. And make sure the window is closed http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

11-03-2004, 11:31 AM
Gear up flaps up window close .


11-03-2004, 12:02 PM
iv had same problem. i cant get it any were neer its yop rated speed abot 220mph sounds about like it to me. high or low alt.

11-03-2004, 12:28 PM
if at low alt, make sure your supercharger is set to '1'. It should be by default, but check it anyway http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

11-03-2004, 12:30 PM
Close the canopy and keep your ears in! http://forums.ubi.com/images/smilies/88.gif

11-03-2004, 12:33 PM
I have the engine stuff on auto?
Do i have to have it on manual.


11-03-2004, 12:37 PM
Are you seeing this 220 mph on the speedbar?

That's Indicated Air Speed, not True Air Speed.

Go to no-cockpit view, note the kph (in no-cockpit it's TAS), and convert to mph

11-03-2004, 12:40 PM
Make sure your prop pitch is all the way up too...

11-03-2004, 01:19 PM
Ther is a huge difference between indicated air speed and true air speed. IIRC, there was a pdf table in FB listing the true value for a given IAS.



11-03-2004, 01:20 PM
I have to echo the original poster. Although the figures are at home, my test showed both the Hellcat and Corsair did not hit their best speeds. I invite others to test as well.

IIRC, the Corsair should hit about 671 kph at about 20,000 feet. I got about 620 kph.

The Hellcat should do about 611 kph at about 25,000 ft. I got about 555 kph.

The test was done on the Okinawa map at the altitudes noted above. Rads were closed, flaps and airbrake (Corsair) up, canopies closed, and true airspeed checked. Both superchargers were at stage 2 and the throttles were firewalled. The planes were run for about 5 minutes. They quickly reached the approximate speeds above and then stayed there indefinately.

I'd be interested to see what others find.

11-03-2004, 02:43 PM
As you climb, Indicated Airspeed (IAS) drops due to less atmospheric pressure at altitude. Two things are needed for an airspeed indicator to work. Ram-air pressure via pitot tube, and static air pressure via static ports. I believe the speed bar illustrates True Airspeed (TAS).

11-03-2004, 05:04 PM
Mix to 120% and supercharger settingsright for the altitude.

11-03-2004, 05:10 PM
i used the true air speed. best i got in auto engine mangment and manule. down low 222 was as fast as she would go. with 25% fuel i gained 10 mph.

11-03-2004, 05:26 PM
Geetarman, I think it is either the Smolensk or Crimean map that is the standard for speed tests as that is standard conditions (more or less) as the rated speeds would have been obtained, whereas Okinawa is going to be a subtropical climate and may affect the speeds obtained.

11-03-2004, 05:34 PM
Just tested it. It goes way fast guys. Turn the cockpit off and look at the wonder woman gauges.

Not much wrong here.

11-03-2004, 05:40 PM
I get 350mph ASI at SL with water injection and 100% fuel on the Crimea map in the D. It should be 359mph at SL with water injection and 237 gal fuel. It could be that it flies a little faster in PF with 25% fuel, but ideally I'd need to check the gallons of fuel carried at 100% or 25% with the USN tests. (The USN test is with rocket rails, bomb shackles and guns and ammunition. Totally clean with no rails, etc. it should make about 380 at sea level)

11-03-2004, 05:40 PM
Few, if any, aircraft in the Pacific could reach their manufacturer's specified maximum speeds because of the high temperatures and humidity encountered in the South Pacific.

Remember that the higher the moisture content of the air (humidity) the lower the oxygen content, hence, less horsepower.


11-03-2004, 06:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ElAurens:
Few, if any, aircraft in the Pacific could reach their manufacturer's specified maximum speeds because of the high temperatures and _humidity_ encountered in the South Pacific.

Remember that the higher the moisture content of the air (humidity) the lower the oxygen content, hence, less horsepower.

http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif <HR></BLOCKQUOTE>I agree with what you and others are saying about various limitations. But even under adverse high humidity and high temperatures, the speeds should not be reduced by 50 to 60 KPH, like the one poster pointed out. That's 31 to 37 mph or 26 to 32 knots difference. As a RL pilot, I'm not good with there being that much loss of speed. Maybe 5 to 15 knots speed loss, but not 26 to 32 knots. Humidity usually doesn't make that much difference and at high altitude, even in the tropics it would get cool, if not down right cold. Especially above 20,000 feet. If it were 90 degrees F at sea level, it should be around 48 F at 20,000ft. And usually high humidity does not make a huge amount of difference, some but not that much.

11-03-2004, 06:33 PM
Thanks for the tip on the
Crimea map. I'll try tonight. Please keep in mind, I attempted to reach both planes' top speed at the best altitude (about 20 - 20K). I did not test at SL.

Curious if anyone gets different results at the altitudes I used

11-03-2004, 06:35 PM
Sorry, one more thing - I believe I used the correct supercharger settings (position 2) on both planes.

11-03-2004, 06:44 PM
Is it just me or does the ASI gauge in the F4U display the incorrect value? It does not match the speedbar reading in neither mph nor knots.

11-03-2004, 07:30 PM
i just checked mine again and its not 230 mph in my game but 330mph true. far cry from 400 mph as far as the whole air temp it runs the same speed on the moscow map as the others.

11-03-2004, 07:40 PM
i reached 350 in the p51 under same condctions

11-03-2004, 09:38 PM
F4u-1A[? the first one on the list]

Object viewer says 670kph@6000m

I get 666kphTAS@6000m on Crimea map, over the water at noon with wind turned off. Seems plenty close enough to me.

ASI matches the speedbar for MPH, but the speedbar drops anything over the increments it shows, so it will look like the cockpit guage is reading higher than what speedbar shows (so if speedbar shows increments of 20 then guage will show 299 looking like 300 and speedbar will show 280). I think the angle you look at the ASI guage from makes it look to read a little high too, so it amplifies the effect.

11-04-2004, 02:51 AM
On the Crimea map in the -1D I get 270-280 mph ASI, which is 380-390 mph TAS at 20,000 feet. The USN rated speed at this altitude for a loaded plane (unknown fuel amount in %) with armament, racks, but no bombs, etc, is 417 mph.
666kph is pretty much dead on correct, though, for the object viewer and the USN figures. I don't know if the -A and -D are behaving differently or if I am testing in a different way somehow.

The 380mph at sea level I quoted earlier might have been for the -4 version (clean) not the -1 version (clean_. (359 is definitely for the -1 version, with racks, though).

11-04-2004, 03:04 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
I believe the speed bar illustrates True Airspeed (TAS). <HR></BLOCKQUOTE>

11-04-2004, 04:43 AM
Try recalibrating your joystick. My throttle slider was out of wack after installing PF.


11-04-2004, 04:59 AM
The USN's (and USAAF's) test proceedure for top speed was done with full tanks, 100% fuel load.
Hence much of hte whining about the speeds attained (or not) by US aircraft in this product.

Be sure.

11-04-2004, 05:06 AM

In that case my SL test is pretty much spot on, but it is odd that my test on the 1D at 20,000 feet makes it seem a little slow, whereas the test someone else did on the 1A seems spot on. I'll test the 1A too. It might be the way I am doing the test.