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Yippee.
09-08-2008, 10:50 AM
My current scheme is hold the nose at a medium angle and run the throttle to 101%, thus engaging the boost. I climb out to 5k this way, then ease off on both the angle and power. The thing seems to come to life and climb all its own from that point on.

See any flaws in this method? Ways to climb faster?

http://forums.ubi.com/images/smilies/typing.gif

PanzerAce
09-08-2008, 11:08 AM
well, you could go to 110% power....and medium angle is REALLY unclear. What kind of climb rate are you achieving?

Generally, I firewall the throttle, and maintain an airspeed of ~350kmph IAS until I get to my desired altitude. Lowering throttle and rpm occasionally if I overheat for some reason.

ytareh
09-08-2008, 11:19 AM
P47 doesnt overheat at high alt (8-10km?)

Boosher
09-08-2008, 12:03 PM
I've had my best results with Step climbs, rad full open, 110% power, between 230 to 250 kph. It generally doesn't overheat and when I get up to about 7k meters I let it cool off in cruise for a while.

Yippee.
09-08-2008, 12:14 PM
Yes, "medium" is pretty darn vague!

http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

I was hoping to keep the topic pretty open to start off. Panzer, I can't give you a climb angle number at the moment, but I guesstimate it's around 12 degrees.

Seems like at 101% I never overheat the engine is ready for a long DF as soon as I reach 5k. So, my facts for the moment are limited to the power setting.

This is rads closed, btw.

thefruitbat
09-08-2008, 12:37 PM
Best climb is linked to a specific IAS speed, plane by plane, which for the p47 is given at 266km/h IAS by il2compare. This will give you a climb value of between 13.5 m/s for a D10, to 14.25 m/s for a D27 late.

The angle to hold 266km/h will be alot steeper at sealevel, than say at 7000m, so its important to realise that its the speed, not the angle that is important.

obviously 110% power rads closed will give best power climb, i generally reduce pitch a little to drop the revs, rather than reduce power, say to 90%.

fruitbat

Buzzsaw-
09-08-2008, 01:02 PM
Salute

When I was testing versions of the P-47 for best climbrate, (way back in Pacific Fighters) I found that 280-290 kph gave the best climb times. That beginning on an airfield, taking off and climbing at full throttle, WEP, opening the RAD as nessesary to prevent overheating. At a certain point, the throttle is reduced to 99%.

However, when flying in enemy areas, it is generally better to keep speed to 350 kph when climbing. This will give a lower climbrate, but keeps the speed high, something which is important if you encounter enemy aircraft. The P-47 has VERY slow acceleration from low speed.

You don't climb in dogfight situations, unless you have a lot of speed, and can outzoom your opponent, and in that case, a smooth low G pullup into a zoom gives the best results.

TinyTim
09-08-2008, 01:12 PM
Originally posted by Boosher:
I've had my best results with Step climbs, rad full open, 110% power, between 230 to 250 kph. It generally doesn't overheat and when I get up to about 7k meters I let it cool off in cruise for a while.

Rads in P-47 don't work. They only cause drag but do not cool the engine down, so you better leave them closed all the time.

In stock version that is at least. Maybe some mod fixed this bug?

TX-EcoDragon
09-08-2008, 04:09 PM
Originally posted by thefruitbat:
Best climb is linked to a specific IAS speed, plane by plane, which for the p47 is given at 266km/h IAS by il2compare. This will give you a climb value of between 13.5 m/s for a D10, to 14.25 m/s for a D27 late.

The angle to hold 266km/h will be alot steeper at sealevel, than say at 7000m, so its important to realise that its the speed, not the angle that is important.
. . .

fruitbat

True, with the exception that the airspeed that results in the best rate of climb (Vy) actually decreases with altitude (until merging with Vx near the service ceiling of the aircraft). Vy also assumes climb power. . .around 100% with radiator open works well enough, you can use more, but keep an eye on the temps.

Also, the ideal climb speed when near a combat area might be a little different than when you are sure you aren't going to get bounced. I for one usually use a Vy climb as much as I can, but when I expect to encounter the bad guys, it's much safer to have more energy in the aircraft, so perhaps instead of using 275 kmh in the climb I'll go to 340. This gives you enough energy to maneuver if engaged. 270 kmh in the 47 gives you little choice but to push over and dive if forced to evade.

DKoor
09-08-2008, 04:14 PM
Dunno about engine settings, I pay more attention in order to make sure that I do most of that climbing out of combat zone, preferably above friendly airspace.

P.FunkAdelic
09-08-2008, 10:05 PM
Someone explain to me the subtlties of Vx and Vy climb. Is x and y meant to denote something about vertical versus horizontal?

WTE_Galway
09-08-2008, 10:17 PM
Originally posted by P.FunkAdelic:
Someone explain to me the subtlties of Vx and Vy climb. Is x and y meant to denote something about vertical versus horizontal?

No subtlety really.

Vx is the best ANGLE of climb speed. Maintaining Vx gives you the most height in the shortest horizontal distance. Useful for not flying into mountains someone inconveniently placed at the end of the runway for example.


Vy is the best RATE of climb. This gives you the most height over time ... you may travel a lot further horizontally to get there but end up at a higher altitude over a given time.


By the way Vy usually happens to be pretty close to the optimal glide speed as well.

P.FunkAdelic
09-08-2008, 10:57 PM
Alright so how do I determine the Vx and Vy for any particular aircraft in IL-2? Do I use IL-2 Compare? Also is there any accurate way of determining your angle of ascent?

Also how do you balance the power settings when attempting to attain Vy? Is it just a matter of managing the the engine to prevent overheating while maintaining the optimal climb speed?

And someone said that optimal speed for Vy changes with height? Is there a way to determine the curve for that aside from trial and error?

WTE_Galway
09-08-2008, 11:38 PM
Originally posted by P.FunkAdelic:
Alright so how do I determine the Vx and Vy for any particular aircraft in IL-2? Do I use IL-2 Compare?

You might be able to look it up for some aircraft. Or maybe you will have to spend some time testing the aircraft in game.


Originally posted by P.FunkAdelic:
Also is there any accurate way of determining your angle of ascent?

Angle of ascent is not angle of attack. Its something that has to be worked out over a period of time so pre-computers there was no instrument that did it. From memory it will be something like TAN^(-1) of height/distance


Originally posted by P.FunkAdelic:
Also how do you balance the power settings when attempting to attain Vy? Is it just a matter of managing the the engine to prevent overheating while maintaining the optimal climb speed?

Choose and set your desired climb power and adjust angle of attack to maintain the desired Vy.


Originally posted by P.FunkAdelic:
And someone said that optimal speed for Vy changes with height? Is there a way to determine the curve for that aside from trial and error?

If you cannot find charts it is just trial and error until you plot your own chart.

P.FunkAdelic
09-09-2008, 12:18 AM
Right, my bad on the ascent vs. attack thing. Is there accurate measuring instruments for angle of attack as well? I see notches on the arti-horizon for banking but I can't offhand recall any for vertical angles of attack on that same instrument.

Generally how accurate are the FMs if I do find real life charts? I've read numerous comments about "too bad this aspect of Plane X isn't like real life".

Great answers. I love how there are no shortcuts in this game. A real challenge for an intellectual like me.

Cheers

Ontopanova
09-09-2008, 01:54 AM
Originally posted by P.FunkAdelic:
Right, my bad on the ascent vs. attack thing. Is there accurate measuring instruments for angle of attack as well? I see notches on the arti-horizon for banking but I can't offhand recall any for vertical angles of attack on that same instrument.

Generally how accurate are the FMs if I do find real life charts? I've read numerous comments about "too bad this aspect of Plane X isn't like real life".

Great answers. I love how there are no shortcuts in this game. A real challenge for an intellectual like me.

Cheers

For combat the most informative spec is the "initial rate of climb" spec for the aircraft. For sustained operational manouvres add "best rate of climb speed" for the aircraft for such things as egress (climbout) and etc..

Some aircraft have a low nose "attitude" at best rate of climb speed (Spit in RL for example); others a higher nose attitude; for example, the Zero had its wingtips twisted allowing it to fly at a higher angle of attack.

There are many other parameters for climb including "sustained climb rate" while
"maximum rate of climb" is more easily sustained in a turning climb rather than straight and level.

But why not just leave the measuring to the Test Pilot?
After all, Newton's Laws of Physics (which on September 10 AEST may be further blown apart with the rest of us from CERN in Switzerland) apply to bodies in momentum.

thefruitbat
09-09-2008, 04:25 AM
Originally posted by TX-EcoDragon:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thefruitbat:
Best climb is linked to a specific IAS speed, plane by plane, which for the p47 is given at 266km/h IAS by il2compare. This will give you a climb value of between 13.5 m/s for a D10, to 14.25 m/s for a D27 late.

The angle to hold 266km/h will be alot steeper at sealevel, than say at 7000m, so its important to realise that its the speed, not the angle that is important.
. . .

fruitbat

True, with the exception that the airspeed that results in the best rate of climb (Vy) actually decreases with altitude (until merging with Vx near the service ceiling of the aircraft). Vy also assumes climb power. . .around 100% with radiator open works well enough, you can use more, but keep an eye on the temps.
</div></BLOCKQUOTE>

Thanks for the clarification http://forums.ubi.com/images/smilies/25.gif

fruitbat

M_Gunz
09-09-2008, 07:29 AM
Originally posted by P.FunkAdelic:
Right, my bad on the ascent vs. attack thing. Is there accurate measuring instruments for angle of attack as well? I see notches on the arti-horizon for banking but I can't offhand recall any for vertical angles of attack on that same instrument.

Bank angle and vertical velocity determine G's of turn.


Generally how accurate are the FMs if I do find real life charts? I've read numerous comments about "too bad this aspect of Plane X isn't like real life".

About as accurate as the sources, cherry picking and added speculation allows.


Great answers. I love how there are no shortcuts in this game. A real challenge for an intellectual like me.

You are either misinformed or are a troll or both, the common variety it seems.



Cheers[/QUOTE]

P.FunkAdelic
09-09-2008, 09:29 AM
You are either misinformed or are a troll or both, the common variety it seems.

What does that mean? I don't get it. Did I say something wrong? http://forums.ubi.com/images/smilies/blink.gif

Bearcat99
09-09-2008, 10:23 AM
Most AC have an ROC (rate of climb) indicator.. Go to M4T and get the Cockpit Reference Guide (http://mission4today.com/index.php?name=Downloads&file=details&id=3265) there and find it. I use elevator trim to climb within the prescribed rates om the dial.. which vary for some AC.. with max power & @95% pp.

Viper2005_
09-09-2008, 12:39 PM
Originally posted by thefruitbat:
Best climb is linked to a specific IAS speed, plane by plane, which for the p47 is given at 266km/h IAS by il2compare. This will give you a climb value of between 13.5 m/s for a D10, to 14.25 m/s for a D27 late.

The angle to hold 266km/h will be alot steeper at sealevel, than say at 7000m, so its important to realise that its the speed, not the angle that is important.


Vy is not necessarily constant over the altitude range, though this is a good first approximation.

There are several reasons for this.

1) As you climb, your TAS increases. This therefore changes the advance ratio of the prop at constant rpm.

2) As you climb, your Mach number increases even faster than your TAS. This usually helps L/D a bit for subsonic aircraft wings, but hurts the prop because its helical tip Mach number increases quite considerably as both the component Mach numbers (due to rotation and forward speed) go up.

Since climb rate is maximised when you maximise SEP, and since drag power requirement isn't that sensitive to speed reduction (since minimum power requirement is produced by maximising L^3/D^2), this tends to result in a slight reduction in Vy as you climb.

This trend is generally complicated by reduction in engine power because as power decreases, torque decreases at constant rpm and therefore the prop's angle of attack will decrease. This decreases its critical Mach number and therefore tends to give you back some of what (1) and (2) take away. In the case of the P-47, thanks to its turbo you get roughly constant power all the way up to the point where you hit the turbine rpm limit and therefore I would expect the reduction in Vy to be slightly more pronounced than in most other aircraft.

Of course this is really getting into fine detail; speed reductions are only a few knots per thousand feet at altitude.

Unfortunately, American test reports tend to provide limited information as to climb speeds used, so for an example of the sort of reduction in use see this Spitfire HF.IX test report:


.4.1. Climbing speeds. The climbing speed used with the 0.477:1 reduction gear and the 4-blade propeller were that deduced from tests on another aircraft as stated in para. 3 (i) above. This speed was 160 mph ASI up to 25,000 ft. (approximately full throttle height in F.S. supercharger gear) decreasing by 3 mph per 1,000 ft. thereafter.

......The partial climbs made with the 0.42:1 reduction gear and the 5 blade propeller showed the best climbing speed to be 160 mph ASI up to 22,000 ft. decreasing by 5 mph per 2,000 feet thereafter.
http://www.spitfireperformance.com/bs310.html

Anyway, depending upon the fidelity of the model, you may well find that you do better at high altitude by flying somewhat slower than IL2 Compare suggests, since it gives Vy for a low altitude (1 km?)...

Kettenhunde
09-09-2008, 02:25 PM
Vx & Vy:

http://www.rodmachado.com/Articles/Article%20of%20Month...0Vy/Vx%20&%20Vy.html (http://www.rodmachado.com/Articles/Article%20of%20Month/Articles-of-Month/Vx%20and%20Vy/Vx%20&%20Vy.html)

And for fun:

http://www.rodmachado.com/Product/Videos/Excerpts/Av-Humor-Mod_popup.html