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P-47D Level Speed

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High folks,

 

Did any of you check the achievable level speed on the P-47D already?

I've tried today at FL 200 and to me the plane feels a tad too slow.

I tried to dial in the precise limits according to the manual.

Normal Power: 2550 RPM, 42'' Hg

Combat: 2700 RPM, 52'' Hg

WEP (with Water Injection): 2700 RPM, 64'' Hg

 

I couldn't get the Turbocharger to it's limits (20000 RPM), it was stuck somewhere at 16k-17k RPM for me.

 

The speeds achieved in my test, with 100 Gal fuel left in the main tank, racks attached but bombs dropped and rocket launchers jettisoned, were...

 

Normal: 245mph IAS

Combat: 255mph IAS

WEP: 287mph IAS

 

That's roughly...

Normal: 335mph TAS

Combat: 350mph TAS

WEP: 390mph TAS

 

According to http://www.wwiiaircraftperformance.org/p-47/p-47.html and this graph...

comp-p47dmn.jpg

...I would have expected the plane to run somewhat faster.

 

Note: I've given the plane 5 minutes to settle on max speed (except for WEP where I had to stop the test 5min after engaging, but the speed didn't change at that time anymore anyway).

The plane was perfectly trimmed and running on auto level stabs.

Outlet cowl flaps fully closed, inlet cowl flaps didn't matter on the speed (checked!), radiator fully open (otherwise engine would overheat), fuel mixture auto rich (85%, tried 100% to no avail).

 

:drinks:

Mike

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2500rpm gives faster level speed than 2700rpm; you have to go +8000m to get speed benefit from the latter.

The radial cowls should be fully closed; if you are going fast and on water injection you should be able to close the oil radiator, too. Inter-cooler flaps offers the lowest drag at 50% and they can be set like that for the whole flight. Open your throttle 100% and then use the turbo boost lever for the manifold-pressure control alone. When on the water injection set the mixture to 100%.

 

That's how to get best performance from "in the sim" P-47D.

 

Could get 310mph (499km/h) indicated at about 20K ft, 50% fuel, empty racks on the Kuban autumn map at full WEP.

Edited by Ehret
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I tested the P-47 with the official configuration (not using lower RPM for example) and compared it with the real life test on a D-22 and the document Gavrick posted:

unknown.png

It's close to the document posted by Gavrick. Also for comparison the D-22 test was using wing racks and my D-28 in game was clean (no wing racks). I heard that the bubble top P-47 had a speed penalty compared to the razorback ones. So looks like a clean bubbletop is a bit behind a razorback with wingracks, unless the D-28 in Gavrick's document was using wing racks as well but I wouldn't know since I don't know what does the document mean with  "design useful load".

2.jpg

Edited by -=PHX=-SuperEtendard

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Posted (edited)

Fun fact: G-4 can catch p-47 at 11km

 

(kuban summer +2c)

Edited by CptSiddy

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13 minutes ago, JtD said:

Not if I fly the P-47.

 

I don't think it matters who flies it, the G-4 is from older IL-2 versions. It is documented fact that many older planes over preformed on high altitudes. Like how A-5 or La-5 were totally bonkers at 10km. 

 

The G-14 started to lose steam at 8km and totally fell flat on its face at 10km and above, the G-4 just got faster after 10km and was catching right to my tail pipe at 11km.  This was on TAW, kuban summer +2C. 

 

 

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Posted (edited)

If you look at this:

 

you will see that early 190s perform to good up high like la5s, 2nd fastest axis airplanes when using boosts, only 109k4 on boost is faster then them on axis side that high.

test only up to 10km

Edited by 77.CountZero

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On 1/6/2019 at 3:20 PM, CptSiddy said:

 

I don't think it matters who flies it, the G-4 is from older IL-2 versions. It is documented fact that many older planes over preformed on high altitudes. Like how A-5 or La-5 were totally bonkers at 10km. 

 

The G-14 started to lose steam at 8km and totally fell flat on its face at 10km and above, the G-4 just got faster after 10km and was catching right to my tail pipe at 11km.  This was on TAW, kuban summer +2C. 

 

 


image.thumb.png.73e51292eb1448e7f2ebeaefc3bae441.png

Yes the G4 is faster than a G14 at very high alt.
but no. Cant catch a 47 by a long stretch.

(yellow is the g14)

Edited by DerSheriff
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On 1/26/2019 at 5:12 PM, DerSheriff said:


image.thumb.png.73e51292eb1448e7f2ebeaefc3bae441.png

Yes the G4 is faster than a G14 at very high alt.
but no. Cant catch a 47 by a long stretch.

(yellow is the g14)

 

your graph shows what he say in quated post, also he says 11km and you show only to 9km.

 

"The G-14 started to lose steam at 8km and totally fell flat on its face at 10km and above, the G-4 just got faster after 10km and was catching right to my tail pipe at 11km.  This was on TAW, kuban summer +2C. "

 

if you show 10 and 11km i bet G4 is as fast or faster then P-47 , just look how hard his lines are droping to left and how G4s are just going strait up almost, 10km diff is probably min. 11km G4 prob faster, like hes say that happend to him. Older airplanes FM are just to weard on high alts, you can see that in your graph also 

 

 

Edited by 77.CountZero

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43 minutes ago, CSAF-D3adCZE said:

Sheriff, do you have climb rates as well?


Yes
Read the alititudes as in "up to X meters" so the 1000m refers to 0-1000m,

and the cyan colored graph is the G-4. for some reason swallowed again.
.image.thumb.png.8ce00d5028a977ba7769c76b1274801c.png
 

Edited by DerSheriff

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Thanks. So if I understand it correctly, P47 should kick german asses above 5ish 6ish km of altitude, unless it is K4, where the Jug gets advantage above 7is or more likely 8ish km of alt?

 

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1 hour ago, CSAF-D3adCZE said:

Thanks. So if I understand it correctly, P47 should kick german asses above 5ish 6ish km of altitude, unless it is K4, where the Jug gets advantage above 7is or more likely 8ish km of alt?

 

A rough (and difficult) parity about 7km with the K4 except you load less guns and have low fuel. At 8-9km things get worse for the Jug but you can switch to the manual pitch and over-rev engine up to the 3000rpm for about 5m. That's improves Thunderbolt performance dramatically when that high.

 

Imho, that pesky 5m emergency timer (with ADI supply for 15m, really?) and no 150 octane fuel makes things more difficult, that they should be. Yet, they will get even more difficult and soon.

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3 hours ago, Ehret said:

 

A rough (and difficult) parity about 7km with the K4 except you load less guns and have low fuel. At 8-9km things get worse for the Jug but you can switch to the manual pitch and over-rev engine up to the 3000rpm for about 5m. That's improves Thunderbolt performance dramatically when that high.

 

Imho, that pesky 5m emergency timer (with ADI supply for 15m, really?) and no 150 octane fuel makes things more difficult, that they should be. Yet, they will get even more difficult and soon.

Engine limits are at least disappointing. But when I went 1v1 Jug vs K4(I was in Jug) I had no problem keeping my energy advantage, I just had to watch not to go below 21k ft. If I was shotdown by K4 it was only because I went below 21k ft.

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I had no difficulties to keep distance from 109s either. You have to spot them in time. from there on you can drag n bag in the Jug very nicely because of the good diving characteristics and the excellent SA.
imho the Jug is fast enough. 150 octane would certainly help however.
 

Edited by DerSheriff

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The Jug is capable of course but it's handicapped by it's engine limits and the fact that it doesn't have 150 fuel/settings.

 

Engine limits should be revised at the very least. I can live without 150 fuel if we get historical/accurate engine limits.

 

There are a few bigger problems with the Jug other than it's engine limits. I'd rather see the other problems fixed first and then take a look at the engine.

Edited by Legioneod
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5 hours ago, Legioneod said:

The Jug is capable of course but it's handicapped by it's engine limits and the fact that it doesn't have 150 fuel/settings.

 

Engine limits should be revised at the very least. I can live without 150 fuel if we get historical/accurate engine limits.

 

There are a few bigger problems with the Jug other than it's engine limits. I'd rather see the other problems fixed first and then take a look at the engine.

 

Pretty much this.

Flying a plane that was originally developed to survive more than a week pretty much puts you at a disadvantage. 

Ridiculous.

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And i still dont understand how they decide that some airplane can recharge their max power settings in combat mode and some not able to do that and have to go in continues like P-47. It should be same for all airplanes recharg only in cntinues or only in combat, not that some have this advantage for no reason what so ever.

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14 hours ago, 77.CountZero said:

And i still dont understand how they decide that some airplane can recharge their max power settings in combat mode and some not able to do that and have to go in continues like P-47. It should be same for all airplanes recharg only in cntinues or only in combat, not that some have this advantage for no reason what so ever.

 

Simple. You model both sides' planes to manual limits, completely ignoring one had stopped caring that their engines' MTBF was 20 hours when the plane was likely to have been shot down before making it to 5.

(Yeah, the numbers are an asspull, but that doesn't invalidate the core sentiment.)

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17 hours ago, 4./JG26_Onebad said:

 

Pretty much this.

Flying a plane that was originally developed to survive more than a week pretty much puts you at a disadvantage. 

Ridiculous.

 

Has always been like that in this sim, only now people start to become more vocal, because it affects their favourite rides.

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9 hours ago, II./JG77_Manu* said:

 

Has always been like that in this sim, only now people start to become more vocal, because it affects their favourite rides.

People just put up with it until now. Before it didn't really cause much trouble, since Russian aircraft don't have much limits and Germans are powerful enough despite the limits, engine limits were still a huge annoyance though.

 

Now that we're getting Bodenplatte engine limits become more of a problem imo due to the fact that American aircraft manuals are very conservative.

American aircraft suffer more than any other due to the way engines are modeled in this game, the limits are not a realistic reflection of what actually occurred in combat and they cause the aircraft to suffer in performance as a result.

 

Timers need to go. The devs need to find a better way to model engines and engine degradation.

Edited by Legioneod
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6 hours ago, Legioneod said:

Now that we're getting Bodenplatte engine limits become more of a problem imo due to the fact that American aircraft manuals are very conservative.

American aircraft suffer more than any other due to the way engines are modeled in this game,

 

In a pure numbers game, the aircraft to suffer most is the P-40 which is not a Bodenplatte aircraft. The US aircraft we get in Bodenplatte don't suffer any more than the average early-mid war German aircraft.

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1 hour ago, JtD said:

 

In a pure numbers game, the aircraft to suffer most is the P-40 which is not a Bodenplatte aircraft. The US aircraft we get in Bodenplatte don't suffer any more than the average early-mid war German aircraft.

But now they are geting popular american airplanes and more ppl will see how their engine managmen is in this game, when i try P-40 i knew that that type of engine menagment will be bad if it stays the same for popular airplanes we will get with bobp, and it did stay the same and complains will just get wors when mitical P-51 comes and you have same limits and funny recharges.

 

in 109s or 190s you just have to think about emergancy use and its 1min or 3min, and then it recgharges while your in combat that lasts 30min, and your realy competative in combat mode vs vvs.

now compare that to amount of things you have to worry about in P-40, P-39 and P-47 regarding the engine menagment, and the level of your atention spend on diff timers is mutch greater, and your competative vs axiis ony if you use max powers, but most of time you have to fly slower then snail on continues setings.

 

in the end you just see more new players just going for what is easy, and that will again be axis airplanes even in bobp

 

and i spend most of my time playing 109E1 in CloD where you dont have this techchat messages like here, where you have to manualy control prop and rpm, and its so mutch easyer and more natural to just play there and lisen  to your engine and know when your over limits or under and looking at your engine temps then how its done in this game. Here you cant judge anything by sound and your engine will just blow away no mather what temp its oil or water is when that timer runs out.

Edited by 77.CountZero
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I said that before and I'll say it again:

 

Fuel consumption and temp management should be the only factor to prevent people from going full throttle, just as it was in real life. 

Yes, increasing the engine life was a factor for engineers and crew chiefs, but trust me it was cheaper to overhaul the engine more often than it was to replace an entire aircraft and train a new pilot because the old ones were too afraid to push the throttle forward and are now embedded into the ground somewhere. 

If you'll spend some time reading through actual after action reports you'll find many sources quoting "I pushed the throttle forwads and ran WEP for 40 minutes because I panicked". 

 

If the engines are modelled properly, people on public servers shouldn't fly on full throttle while cruising at all time simply because they'll run the engine too hot and will actually end up having to decrease power when getting into slow climbs or turnfights.

If that's not enough of a reason, mission builders can always decrease the fuel load on aircraft to an amount that will make people have to think twice about running WEP for 30 minutes, cause that might be enough to burn through the entire tank (looking at you FW-190D). 

 

I think the devs had a good and creative idea while modelling the engine ratings, but there's a reason why this series is like, LITERALLY THE ONLY SIM that does it. There's no worse feeling than having to think "how long did I run WEP for" rather than just being able to take a sweep around the cockpit, making sure that T's and P's are all in check and carry on with the fight.

Edited by 4./JG26_Onebad
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On 1/29/2019 at 3:09 PM, DerSheriff said:


Yes
Read the alititudes as in "up to X meters" so the 1000m refers to 0-1000m,

and the cyan colored graph is the G-4. for some reason swallowed again.
.image.thumb.png.8ce00d5028a977ba7769c76b1274801c.png
 

Nice chart.

 

Those climb rate figures are absurd through from a realism standpoint however. The both the P-47 and G-14 are massively over-performing to essentially comical levels. It get that is not finished etc but jesus christ. And the P-47 can do sustained 24deg per second turns with its flaps out.

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43 minutes ago, Fumes said:

Nice chart.

 

Those climb rate figures are absurd through from a realism standpoint however. The both the P-47 and G-14 are massively over-performing to essentially comical levels. It get that is not finished etc but jesus christ. And the P-47 can do sustained 24deg per second turns with its flaps out.

 

If you look at chart it says 400l p-47, thats 29% of fuel, on combat + 5min boost you run out of fuel in ~22min, while G14 is probably with also 400L what is 100% for it, and you can fly on combat+ emergy for ~40min. P-47 800l atleast and 8 guns would be normal setup, no one takes that low 29% of fuel on 47 and 4 guns only on normal servers.

So you have 109s with 100% fuel in chart compared to P-47s with 29% fuel and one with 58%. Fuel taken for tests should be same in duration of use of that fuel on max powers for both airplanes to show real relashonship betwen them, not to be same in quantity, 109 is already 2000kg lighter then P-47 whats the point of both having same kg of fuel if one eats that fuel mutch faster like its case in p-47 here, so chart dont shows them at same starting points.

Edited by 77.CountZero

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47 minutes ago, Fumes said:

Nice chart.

 

Those climb rate figures are absurd through from a realism standpoint however. The both the P-47 and G-14 are massively over-performing to essentially comical levels. It get that is not finished etc but jesus christ. And the P-47 can do sustained 24deg per second turns with its flaps out.


The one for reference would be the P-47 with half fuel (700 liters) and standard ammo load. Removing four guns and loading 400L fuel is around 500 Kg of weight reduction from that configuration. I think the G-14 was also tested at half fuel.

Edited by -=PHX=-SuperEtendard

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17 hours ago, 4./JG26_Onebad said:

I said that before and I'll say it again:

 

Fuel consumption and temp management should be the only factor to prevent people from going full throttle, just as it was in real life. 

Yes, increasing the engine life was a factor for engineers and crew chiefs, but trust me it was cheaper to overhaul the engine more often than it was to replace an entire aircraft and train a new pilot because the old ones were too afraid to push the throttle forward and are now embedded into the ground somewhere. 

If you'll spend some time reading through actual after action reports you'll find many sources quoting "I pushed the throttle forwads and ran WEP for 40 minutes because I panicked". 

 

If the engines are modelled properly, people on public servers shouldn't fly on full throttle while cruising at all time simply because they'll run the engine too hot and will actually end up having to decrease power when getting into slow climbs or turnfights.

If that's not enough of a reason, mission builders can always decrease the fuel load on aircraft to an amount that will make people have to think twice about running WEP for 30 minutes, cause that might be enough to burn through the entire tank (looking at you FW-190D). 

 

I think the devs had a good and creative idea while modelling the engine ratings, but there's a reason why this series is like, LITERALLY THE ONLY SIM that does it. There's no worse feeling than having to think "how long did I run WEP for" rather than just being able to take a sweep around the cockpit, making sure that T's and P's are all in check and carry on with the fight.

 

This. I can't tell you how many times I've withheld pushing the throttle forward because I was afraid of blowing the engine mid-combat.

This absolutely needs to change, no pilot was afraid that their engine would blow in combat.

 

German and Russian aircraft I don't even think about, I just go full throttle when needed because I know they'll last when needed.

 

American aircraft on the other hand are horrible with engine limits. I'm constantly on edge worrying whether or not I'm gonna blow my engine. It's impossible to keep time as well because I get into one fight and then another and I lose track on how much time has past.

 

Engine timers make it stressful to fly and really ruin some of the enjoyment of this game. This is one of the most pressing issues with the sim currently imo, and it will only get worse unless the devs admit that their engine limits suck and make an effort to change them.

 

There have been plenty of good ideas offered already in the P-47 WEP thread, Devs just need to take the leap and test them out with the community to see what works best.

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46 minutes ago, -=PHX=-SuperEtendard said:


The one for reference would be the P-47 with half fuel (700 liters) and standard ammo load. Removing four guns and loading 400L fuel is around 500 Kg of weight reduction from that configuration. I think the G-14 was also tested at half fuel.

I think its 100% for 109s as that 400l is 100% on 109s and thats why P-47 is also shown with that 400l number.

Edited by 77.CountZero

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Problem with P47 is that fuel consumption is so high so for a standar sortie of more or less 45 min / hour you take off with a lot of fuel and your performance is going [edited] on the beguining and much better with 25 min on the air and so..

Edited by SYN_Haashashin
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1 hour ago, Sgt_Joch said:

I have read many AARs, but never saw any where someone ran WEP for 40 minutes. 

 

Care to post the link to your "many sources".

 

Dunno the other poster but I don't have for "40 minutes", at least no explicitly. However, I have "fifteen minutes at 74" and the implicit one where one Mustang chased ("balls-out" for 10m) group of 11 FW 190, shot down one and escaped ("broke violently for home - full bore").

Edited by Ehret

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On 2/2/2019 at 2:57 PM, -=PHX=-SuperEtendard said:


The one for reference would be the P-47 with half fuel (700 liters) and standard ammo load. Removing four guns and loading 400L fuel is around 500 Kg of weight reduction from that configuration. I think the G-14 was also tested at half fuel.

That still would not buy you anywhere close to the performance we see. 500kg of weight doesnt get you from 17m/s to 23. You can look at alot of P-47 performance charts, or even other aircraft and examine the sort of improvements that come from weight or power changes. Its never this dramatic.

 

p47m-n-climb.jpg

You can see from this chart that a 1300kg difference at similar power yielded roughly 1000ft/min. In il2 were are losing 1/3rd the mass and getting 1.5 times as much climb improvement.

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22 minutes ago, Fumes said:

That still would not buy you anywhere close to the performance we see. 500kg of weight doesnt get you from 17m/s to 23. You can look at alot of P-47 performance charts, or even other aircraft and examine the sort of improvements that come from weight or power changes. Its never this dramatic.


You can see from this chart that a 1300kg difference at similar power yielded roughly 1000ft/min. In il2 were are losing 1/3rd the mass and getting 1.5 times as much climb improvement.


Well Sheriff slowest P-47 test was a bit heavier than the standard one, as it had 100 liters more of fuel and extra ammo. Making it weight around 6250 Kg (standard would be 6000 Kg), the lightest configuration weights 5503 Kg. So it's a ~750 Kg reduction, making it go from ~18.7 m/s to ~23 m/s, a 4.3 m/s difference. The relation is still higher than in the P-47 N/M comparison though.

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The P-47-N has a different wing. Essentialy bigger (42ft vs 40ft span and 322sq ft vs 300 sq ft surface) and with a different profile. Apples and oranges if you want to compare figures.

Not implying that in the game it is right or wrong but only that -M vs -N is not a valid comparison.

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1 hour ago, HR_Zunzun said:

The P-47-N has a different wing. Essentialy bigger (42ft vs 40ft span and 322sq ft vs 300 sq ft surface) and with a different profile. Apples and oranges if you want to compare figures.

Not implying that in the game it is right or wrong but only that -M vs -N is not a valid comparison.

Its not apples to oranges. The bigger wing should if anything help the N model. They are close enough given how insanely small the difference is. But you need not rely on just that example. There are tons of example of flight tests done at different weights on the same or nearly same airplanes. The differences are never as big as this game is showing. Not even close.

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3 hours ago, Fumes said:

That still would not buy you anywhere close to the performance we see. 500kg of weight doesnt get you from 17m/s to 23. You can look at alot of P-47 performance charts, or even other aircraft and examine the sort of improvements that come from weight or power changes. Its never this dramatic.

 

p47m-n-climb.jpg

You can see from this chart that a 1300kg difference at similar power yielded roughly 1000ft/min. In il2 were are losing 1/3rd the mass and getting 1.5 times as much climb improvement.

 

More like the M gains over 23% in mass and the resultant climb rate is reduced by almost 15%.

Meanwhile, the ingame P-47 - and I'm rephrasing your own numbers here in order to get the comparison to go in the same direction - gains 50% in weight (your 1/3) and loses 33% of its climb rate (your 1.5 times).

Oh look! The changes in climb rate for their corresponding reduction in mass correlate!

 

You, sir, fail at statistics.

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1 hour ago, Fumes said:

Its not apples to oranges. The bigger wing should if anything help the N model. They are close enough given how insanely small the difference is. But you need not rely on just that example. There are tons of example of flight tests done at different weights on the same or nearly same airplanes. The differences are never as big as this game is showing. Not even close.

So that ( helping the N model) would make the difference bigger for the M model if both had the same wing (The -N would climb worse with the normal wing and the roc difference would be bigger in favor of the M model). I do not know by how much but it would. And that, if I am not mistaken, goes against your point. So I still stand that is apples to oranges for a direct comparison.

Otoh, I do agree that other flight tests (same plane with different TO weight) would be better.

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53 minutes ago, PainGod85 said:

 

More like the M gains over 23% in mass and the resultant climb rate is reduced by almost 15%.

Meanwhile, the ingame P-47 - and I'm rephrasing your own numbers here in order to get the comparison to go in the same direction - gains 50% in weight (your 1/3) and loses 33% of its climb rate (your 1.5 times).

Oh look! The changes in climb rate for their corresponding reduction in mass correlate!

 

You, sir, fail at statistics.

Not really. I was not converting my numbers into percent, merely pointing out the differences in proportions since that was really all that was necessary to get the point across. But since that eluded you...

 

The in game plane goes from a P/W of 0.18 to a power to weight of 0.21. So for a power to weigh change of 16%, we got a climb rate change of 35%.

 

The N to M comparison as a power to weight change from .17 to .21. So for a power to weight change of 23% we get a climb rate change of 23%.

 

These clearly do not correlate.

 

 

 

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2 minutes ago, Fumes said:

Not really. I was not converting my numbers into percent, merely pointing out the differences in proportions since that was really all that was necessary to get the point across. But since that eluded you...

 

The in game plane goes from a P/W of 0.18 to a power to weight of 0.21. So for a power to weigh change of 16%, we got a climb rate change of 35%.

 

The N to M comparison as a power to weight change from .17 to .21. So for a power to weight change of 23% we get a climb rate change of 23%.

 

These clearly do not correlate.

 

 

 

And one of the reasons why they do not correlate it is because the -N in your comparison has a bigger and different wing that tend to favor it in the climb. That is making the direct comparison faulty unless you know by how much does it improves the climb rate and you factor it in your calculations.

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52 minutes ago, HR_Zunzun said:

And one of the reasons why they do not correlate it is because the -N in your comparison has a bigger and different wing that tend to favor it in the climb. That is making the direct comparison faulty unless you know by how much does it improves the climb rate and you factor it in your calculations.

Again, as you agreed earlier, you can find that this does hold water simply by looking at many other aircraft...identical aircraft...compared at difference weights. Many climb rate charts even have performance at different weights....

 

 

That being said, given the significantly more massive difference in performance change....this comparison is close enough. Especially since the overwhelmingly dominant factor in climb performance is thrust to weight.

 

 

 

 

 

 

 

 

 

 

 

As can be seen here a 24% percent difference in power to weight yields a 29% difference in climb approximate. A significantly smaller change per percent than what we see in il2.

 

p-51h-booklet-pg15.jpg

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