For maximum speed in level flight, what is the optimum setting for throttle and prop pitch? What about for the P-47?

I never had this instability problem with any of the P-51 and I always fly with 50 fuel as well. I must be flying it differently than most people. Although my INPUIT settings are all 100% as well so any p-51 instability should be magnified for me and I dont feel any of it.

quote:

Originally posted by runyan99:
For maximum speed in level flight, what is the optimum setting for throttle and prop pitch? What about for the P-47?

I've tooled around with this for quite a bit, and i think most of what prop pitch does for top speed is placebo. Other's are welcome to disagree, but i haven't seen any level flight performance gain by using anything less than 100 on either plane.

I could explain why, but i'd rather not lose you in the explanation of the mechanics, just know that a constant speed prop adjusts the pitch for you, and all you need to do is set the rpms to the engines maximum torque settings, which happens to be 100% prop pitch for both planes.
Remember that for these planes "prop pitch" is really just the rpm setting that the CSP will maintain.

It gets convoluted when you are descending or diving, or attempting to hang on the prop, but just for speed and straight line level performance 100 is fine.

As for throttle, 100 or WEP is going to give you the best performance. Don't let anyone tell you less throttle and less pitch equals more speed. At least the way i figure, is that lowering pitch means you are lowering the rpms so the engine will be producing less torque, and by not having more throttle you aren't using as much horsepower. The combination means less overall output.

You better read the Manual for the P-51 (AAF MANUAL 51-127-5) and (TECHNICAL ORDER No. 01-60JD-1) and that tells you that flying at 100% with no proper Manifold pressure setting and rpm is just wasting fuel and overheating the engine.

The P-47 is a different beast to fly but with the Mustang YOU MUST set manifold aintake pressure and rpm settings. This is accurately modeled in the game with you constantly watching the "Hg" when you change the power settings and tweaking the rpm with Prop Pitch.

The Packard Merlin engine produces different HP depending on the Manifold pressure/rpm combination as well as at what alt it is applied. Here are some basic all on AUTO RICH settings.

NORMAL:

Take off: 1490HP at 3000rpm (~40"Hg)

(at 13k feet) 1590HP at 3000rpm at 61"Hg

(at 27K feet) 1370HP at 3000rpm-61"Hg

PLANE LIMITS:

Take off Max: 61" at 3000rpm
War Mergency: 67" at 3000rpm
Militray power: 61" at 3000rpm
Max continous: 46" at 2700rpm
Max Cruise: 42" at 2400rpm

OPERATING RANGE:

Manifold Pressure: 29-37"Hg

RPM: 1850-2320

MAX airspeed is 505MPH.

So, Wright's post was intriguing enough that I did some basic tests. Feel free to dispute, but this is what I found:

Plane was P-51D-20NA, 50% fuel, limited fuel on, full MG ammo. Starting altitude was 3km, but I fiddled around with thing all the way up to 8km, before I settled on how to test it. Radiator was closed through the entire flight.

I basically played with power/pitch settings:
90% Throttle w100% pitch
90% Throttle w 80% pitch
70% Throttle w100% pitch
70% Throttle w 80% pitch

100% pitch centered on about 3,000 rpm for both power settings
80% pitch centered on 2,800 rpm for 90%, and 2,700 for 70%

90% ended up being around 58" at 100% pitch, and 51" at 80% pitch
70% ended up being 46" at 3,000rmp, and 42" at 2,700 rmp (that may be speed dependent, I'll have to check the replay)

Basically, at 90% throttle 100% pitch, it hit 670-680kph. 80% seemed a bit slower, but not noticeably so. 70% throttle with 80% pitch, however, hit ~650kph, while increase the pitch to 100% would result in a noticeable speed loss. Starting from 680kph at 90%+100% pitch, and fire walling it, it made it up to 700kph before the engine overheat warning popped up.

Yet at the 2nd go around, with 75% pitch and 90% power, it seems to have the same speed, but with better acceleration, and now 75% pitch +70% power seems to want to do 670kph.

This plane is one odd duck.

quote:

Originally posted by HarryVoyager:
So, Wright's post was intriguing enough that I did some basic tests. Feel free to dispute, but this is what I found:

Plane was P-51D-20NA, 50% fuel, limited fuel on, full MG ammo. Starting altitude was 3km, but I fiddled around with thing all the way up to 8km, before I settled on how to test it. Radiator was closed through the entire flight.

I basically played with power/pitch settings:
90% Throttle w100% pitch
90% Throttle w 80% pitch
70% Throttle w100% pitch
70% Throttle w 80% pitch

100% pitch centered on about 3,000 rpm for both power settings
80% pitch centered on 2,800 rpm for 90%, and 2,700 for 70%

90% ended up being around 58" at 100% pitch, and 51" at 80% pitch
70% ended up being 46" at 3,000rmp, and 42" at 2,700 rmp (that may be speed dependent, I'll have to check the replay)

Basically, at 90% throttle 100% pitch, it hit 670-680kph. 80% seemed a bit slower, but not noticeably so. 70% throttle with 80% pitch, however, hit ~650kph, while increase the pitch to 100% would result in a noticeable speed loss. Starting from 680kph at 90%+100% pitch, and fire walling it, it made it up to 700kph before the engine overheat warning popped up.

Yet at the 2nd go around, with 75% pitch and 90% power, it seems to have the same speed, but with better acceleration, and now 75% pitch +70% power seems to want to do 670kph.

This plane is one odd duck.

Good stuff, but I gotta remind you. The wings come off at around 500 MPH.

The instruments for P51-20NA are in english feet/miles per hour not meters or kilometers. It is easy to get mixed up after flying 109s.

643 Kilometers per hour = 400 mph
724 Kilometers per hour = 450 mph

You might want to reword you posting.

I've been trying to get back in the virtual cockpit to get some of these tests a go as well.

Alas, too busy for now... maybe couple more days.

I think you can toggle the speed bar to go from KPH to MPH. Can't do anything about the instruments.

Now that I think of it, that is probably why there has been alot of confusion when your read other postings and they don't quite make sense. LOL

I was using the TAS gauges from the Ctrl-F1 cockpit, which are all in metric, so those are the actual numbers I was reading off, not conversions from the true cockpit gauges.

It makes it interesting, because the engine gauges and the ball are in the true cockpit, while the speeds and altitudes are in the Invisiplane view.

I thought the Speed bar was Indicated airspeed?

I actually don't know how to convert IAS into TAS. When I fly, I generally fly by the IAS, with the logic 200mph bad, 300mph good, 400 even better, 500mph too much of a good thing.

From what I've seen, it's 500mph IAS that rips the wings off, not 500mph TAS. When I was goofing around the Mustang MkIII tests, I ended with a 90 degree power dive, and it was around 1,150kph that the wings left me. I want to say that 655kph TAS at 8km is about 260mph at 26,250ft.

What I'm beginning to see about the P-51, is that this is a plane that can toodle about at 70% power, and still be hurtling along at a true 400mph at some god-awful high altitude. When it spots somebody it falls on them like some sort of drop-bear, pops them, then resumes its post in the rafters before anyone really knows what hit them.

So, I think the real question now is, anyone got settings for the Mk III and it's 75" boost?

quote:

Originally posted by X32Wright:
You better read the Manual for the P-51 (AAF MANUAL 51-127-5) and (TECHNICAL ORDER No. 01-60JD-1) and that tells you that flying at 100% with no proper Manifold pressure setting and rpm is just wasting fuel and overheating the engine.

Its interesting you brought this up because i think to some extent the game is very limited but with the P-51 there seems to be more consideration with the HG setting.

The thing is when i'm flying, i might kick the engine down to 80 percent throttle and 90 percent prop pitch and i can usually maintain 200-250IAS in level flight.

However, if i'm in a fight, its 100 prop and WEP and i even let it run hot. My reasoning is that you will have more speed and torque at those settings than trying to match what the manual says. I don't believe it to be a waste of fuel if the plane is going faster, and normally running the engine hot is fine so long as you only engage the enemy for a few minutes and then get clear to cool her down.

Prop pitch in the P-47 is used completely differently. It seems to fall faster when i nose over and use 50 percent prop pitch and it will hold a higher speed for longer if i gradually raise pitch as i level out. Speeds are in excess of 500mphIAS.

The other thing to do, is in a spiral climb, maybe escaping an enemy who is attempting to follow, as I approach stall speeds i kick pitch down to 70, and if i'm anxious sometimes more. I hear the RPM drop but as its doing that its actually shoveling more air over the control surfaces allowing you to hang above your enemy while he stalls out.

You can do this in any plane, but some are better at this maneuver than others. The P-47 is a bit more forgiving if you stall with your nose up, which is actually needed to make the maneuver beneficial. Its not recommended in planes that whip into a tail spin easily or even go flat.

I think i've been kicked for doing this, but with proper technique anyone can do it.

Flying P-51Cs today (4.08) I was getting much better speed with WEP+110% throttle, and reducing RPMs until they fell within the little green band on the Tachometer. I got bounced by a 109 low over the english channel and was running the engine HARD for a long time without any overheat. Every time he got close I simply pointed the nose slightly down and firewalled the throttle. Once I was far enough away I zoom climbed and maneuvered for a shot. After a prolonged engagement he eventually stalled it out and crashed. I hadn't overheated once.

I'm with you Swagger. I think most of the people that talk about P-51 throttle/PP settings are looking for a placebo, and many of them don't seem to understand that ICE engines don't really give a hoot if they're in an aircraft or a car. More manifold pressure = more air/fuel entering the cylinders = more power. Period. End of story. Engine RPM is going to be a little more subjective, but again, if it makes max power at 3k, that's the only place it's going to make that power. So if you want to go fast, max out your manifold pressure (ie: push the throttle to the stops), and let it hit 3k rpm (ie, 100%PP)

quote:

Originally posted by HarryVoyager:
I was using the TAS gauges from the Ctrl-F1 cockpit, which are all in metric, so those are the actual numbers I was reading off, not conversions from the true cockpit gauges.

It makes it interesting, because the engine gauges and the ball are in the true cockpit, while the speeds and altitudes are in the Invisiplane view.

I thought the Speed bar was Indicated airspeed?

I actually don't know how to convert IAS into TAS. When I fly, I generally fly by the IAS, with the logic 200mph bad, 300mph good, 400 even better, 500mph too much of a good thing.

From what I've seen, it's 500mph IAS that rips the wings off, not 500mph TAS. When I was goofing around the Mustang MkIII tests, I ended with a 90 degree power dive, and it was around 1,150kph that the wings left me. I want to say that 655kph TAS at 8km is about 260mph at 26,250ft.

What I'm beginning to see about the P-51, is that this is a plane that can toodle about at 70% power, and still be hurtling along at a true 400mph at some god-awful high altitude. When it spots somebody it falls on them like some sort of drop-bear, pops them, then resumes its post in the rafters before anyone really knows what hit them.

So, I think the real question now is, anyone got settings for the Mk III and it's 75" boost?

Yipes, and I thought it was complicated just going from KPH to MPH. I think in terms of instrument values as IAS now you mention Ctrl+F1 TAS.

Ctrl+F1 brings up the HUD/WonderWoman view, but as you cycle through CTL+F1 you get several views. If you set a key for the speed bar it circles through 3 choices on the bar, Knots,Kilo,Miles. Then if you look at the big instruments view in the HUD there are different values.. TAS I guess.

I dont't think of the HUD view at all in flying the P-51, because C.E.M. doesn't work with it.
Especially the P51, if you are monitoring manifold pressure and RPM.

I don't think I've flown the HUD in over 5 years. I had forgotten all about the instrument values compared to the speed bar values. Also, I turn off speed bar, it just confuses things for me.

I fly with conventional measurements in the aircraft. US feet/mile, German meters/kilo,etc. Didn't plan it that way, guess I'm always looking for a simpler way to do things. Multiplying meters x 3 has always given me a basis for coping with speed and altitude, since I am an American. It is easier for me to think in those terms (speed/distance) since I deal with them on a daily basis.

Anyway, it would appear when we start talking about speeds and altitudes it might be a best course to explain carefully the values we are discussing.

This message has been edited. Last edited by: nearmiss,

Since we already have a thread, thought I'd post here:

It seems that there is a strange bug with the P-51. Sometimes when I receive damage to the engine, and it stops, I am able to restart it, and it works just fine! Lol. Am I going crazy or what?

There are pilots who fly the P-51D online in 4.08m and 4.09m on full real servers who can dogfight with and shoot down anyone.

Their mod is BRAINS. Pilots like Ultima Latet, and Rambo51 will fly circles around you at high or low speed in the P-51.

And they are not the only two.......

Get into a server on HL with these guys and watch what they do if you want to get good at flying the Mustang....

I've been replaying trk files of P-51 online players.

It appears they do use the trim, prop % etc. They fly just like the old Jane's WW2 fighters AI. They zoom climb and drop on the enemy at very high rate of speed. Targeting is difficult and they miss quite alot..but they stay alive and loop the loop again and again.

The P51 speed is a pretty awesome asset. Keep up the speed making passing shots and keep going full tilt.

Heck, I don't know how for real that is, but it appears to be the most used tactic.

I would like to see some trk where online P51 pilot actually applied some alternative tactics, besides diving, running, and zoom climbing. I'm not knocking the tactics it just seems to me that after you become more experienced you'd want to do more "engaging" with the enemy. I say that because I think it is important to win, but I think the way you win adds alot to the experience.

==============

Bearcat made a posting on 1C that was pretty important. He indicated in the Il2 application the length of the P51 was set at 9.38 meters, when it fact it is actually 9.83 meters (appx 18"). I'm just wondering what that will do with the COG, and just how different that will make the shorty (9.38 meters) P51 actually fly.

I wonder what this means. We can fly with more fuel or will it mean we'll all be flying with drop tanks and doing combat at 25% fuel.

Trimming the aircraft shouldn't be a full time job like it is now. LOL

I'm amazed this kinda variance is still in the code, after 10 years and a zillion whines and complaints.

ive played on that 109 v p51 valor map, in both planes, and i think the Mustang is easier. It really just comes down to visibility and response. I can fly circles in a 109, but its one of the tougher pits to see out of the front, and its lower elevator authority at higher speeds is quite a contrast to the Mustang. If you want to get good in a Mustang, fly a 109 high and fast for a bit. Its really quite a different plane, i've just never found the Mustang that hard to fly as other people make it out to be, even at over 50 percent fuel load. It is hard to fly the Mustang like a Zero. If you fly it how it was intended it is one of the better planes in the game.


I'm trying to think of other fairly even match ups in the game.