greenie
SOH-CM-2022
Thank you Mike .
Is it possible to make a longer loop ? I've never been involved with sound so I am not sure what's required . Hope Im not pushing my luck !!
...anyhow I am glad that you are looking at it.
Cheers
Flight Replicas P-40N Released [Payware}
- Thread starter mike_cyul
- Start date
Thank you Mike .
Is it possible to make a longer loop ? I've never been involved with sound so I am not sure what's required . Hope Im not pushing my luck !!
...anyhow I am glad that you are looking at it.
Cheers
Not to belabor the point, but I don't think 1480 is available for the -81. Reference data from both the "Operational Suitability Report" and the "P-40N Aircraft Manual". With 100 octane, 1200 hp is rated power, at 52", because that's all the motor will pull static at SL. 1,360 @ 57" is the max the motor will pull at SL, in flight at speed (ram). 55" looks like it is available to ~10k, then MP gradually decreases from full throttle height until at 15k it's down to 43.5 (from the "P-40N_Operational_Suitability" doc - that is consistent with Emergency Maximum (full throttle, 44.2 in) at 14,200 in the Aircraft Manual, and TAS peaks around there.
The single stage, single speed supercharger looks like it only produces 57" at SL with ram, then 55" limit is used to determine FTH, which I think was around 9200ft. Above that you get an MP decrease, to the point where you are technically only able to pull "Mil Power" rating with a 15 minute limitation, also described in the Aircraft Manual chart as "Emergency Maximum". That's an odd thing to call 44" for this motor, but description of power ratings varies over time, between different engine types, and aircraft manufacturers.
That engine data should be good for the STD, fighter bomber variants, etc in this package, and I think that's the data Bernt is looking at. The are a few lightweight variants; apparently the earliest model P-40N was intended for better climb rate and higher altitude performance. To that end, lighter weight would most benefit climb rate, and a change in configuration of supercharger etc would really be necessary for a significant airspeed increase at altitude. Later war lightly configured trainers etc had the STD motor.
My point being, most of these had a standard motor; the early lightweight may have had some special prototype work or a slightly differently configured motor.
fsxar177
Long-Time Enthusiast
I understand where you are coming from. Perhaps you are correct, that the 1480 isn't available. However, that's what their power curve says.. You mention 9,200ft, that sounds about right. I know it would only make about 44.5" at 15,000, wide-open, so that 9:6.1 gear ratio must be set-up for around the 9K mark, I should suppose.. Just guessing.
I would be happy if the fighter/bomber was not capable of the 378mph, but I should expect the upper 340's as listed in all of the performance charts I've seen. Not the upper 290's/lower 300's that I'm seeing....
From most of the technical data I've researched, be it North American, Goodyear, Republic, Curtiss, or the War Dept., whatever, when these test reports are written they will include notes for any ab-normal modifications that the engine/aircraft may have had. Otherwise the tests would not be valid. These reports don't indicate that.
Vought discovered, while testing the Corsair(s), that removing the matte wing walk gained about 7mph TAS. So that was noted. Stuff like that.... Gun blisters, vs. faired over leading edges, or camo-paint vs. flat olive... Things like this were tested. I hardly believe that any serious engine mods would not be listed. So when it says a V-1710-81 was used, and their notes show the power-curve for -81 (F series) and -83/-85 (E series) (same super-charger gear ratio(s), different front case cover) and that curve show's 1480 b.h.p... Well, sounds about right to me. Especially if it's official rating is 1,360. These documents were written during war-time, for the sake of a weapon that was being entrusted to our boys. So I trust, in general, that the reports are as accurate as possible.
I highly respect Mr. Stolle's work. Though very unconventional in this case, regarding some .air/.cfg entries.... I could care less what they look like on paper, if the aircraft performs correctly, given the restrictions of the simulator. I wouldn't even bring it up, but this product is of such outstanding quality, and worth every penny, I feel it's owed to the developers to have a little input.. Before Mike get's the installer out to the various stores.
Best,
Joseph
Some additional insight, perhaps:
http://www.warbirdsresourcegroup.org/URG/v1710_design.html
"The engine design benefited from the General Motors philosophy to build-in production and installation versatility. The engine was constructed around a basic power section from which different installation requirements could be met by fitting the appropriate Accessories Section at the rear and a tailored reduction gear for power output at the front. This approach allowed easy changes of the supercharger(s) and supercharger drive-gear ratio. That gave different critical altitude ratings ranging from 8,000 to 26,000 feet (2,400 to 7,900 m). It allowed a variety of propeller drives and also remote placement of the reduction gear."
https://en.wikipedia.org/wiki/Allison_V-1710
[SUP]
I think the early P-40-1-CU lightweight fighter probably had a different than standard for P40N gear supercharger gear ratio, as that was an easily changeable feature of the basic motor.[/SUP]
http://www.warbirdsresourcegroup.org/URG/v1710_design.html
"The engine design benefited from the General Motors philosophy to build-in production and installation versatility. The engine was constructed around a basic power section from which different installation requirements could be met by fitting the appropriate Accessories Section at the rear and a tailored reduction gear for power output at the front. This approach allowed easy changes of the supercharger(s) and supercharger drive-gear ratio. That gave different critical altitude ratings ranging from 8,000 to 26,000 feet (2,400 to 7,900 m). It allowed a variety of propeller drives and also remote placement of the reduction gear."
https://en.wikipedia.org/wiki/Allison_V-1710
"F" series engines were designed for late model pursuit aircraft, and are identified by the compact external spur gear-type reduction gear box. Military models were V-1710-27, -29, -39, -45, -49, -51, -53, -55, -57, -61, -75, -77, -81, -87, -89, -91, -95, -99, -101, -105, -107, -111, -113, -115, -119, producing 1150 to 1425 hp at 3000 rpm. The V-1710-101, -119 and -121 models has an auxiliary supercharger, some with a liquid cooled aftercooler. Supercharger gear ratios were: 6.44:1, 7.48:1, 8.10:1, 8.80:1 and 9.60:1 depending on altitude rating. These engines had either a six or twelve weight crankshaft, revised vibration dampeners that combined to allow higher engine speeds, SAE #50 propeller shaft, and higher horsepower ratings. The "E" series and "F" series engines were very similar, the primary difference being the front crankcase cover, which was interchangeable between the two series engines.[SUP][11]"[/SUP]
I think the early P-40-1-CU lightweight fighter probably had a different than standard for P40N gear supercharger gear ratio, as that was an easily changeable feature of the basic motor.[/SUP]
fsxar177
Long-Time Enthusiast
Excellent information. The gear ratio listed in the test bed I referenced was 9.6:1. This was the 'high' gear, and pretty standard in the 'N' I believe. (and the -81 in general) If I recall, it's what John Curtiss Paul has in 'Parrothead', which has raced at Reno (ahead of stocker Mustangs) in recent years, not to make any relevance of it.
The 1360hp rating referenced earlier, is essentially a sea level rating. It's also a WEP (emergency power rating, at 57" 3000RPM) So it's to be expected that at higher altitude (and it's many benefits), with the single stage supercharger at it's best peak, and prior to boost dropping off, that the engine would make more power. (the 1,480hp noted)
With the later developments of the Allison, it really makes one wonder, at what point would it be a superior engine to the Merlin? Certainly favored among the ground crew.
A little-known truth, is that many of the over-boosted race Merlin's seen at Reno for years, have actually used modified Allison connecting rods, for their strength and mass. Allowing extreme boost, and rpm as high as 3,600! (Even claims of 3,800 in one pony, at one time...unreal!)
- Joseph
1. With the new files you'll get maximum power and hence maximum speed (350mph) at slightly above 9200ft and at SL a tad more than 310mph.
2. That's why she e.g. feels and handles and spins more realistic than the 'other' P40.
fsxar177
Long-Time Enthusiast
Just tested a few items. The aerodynamics/engine/prop combination is not specifically tuned to achieve the correct performance only at a specific hp setting, it's realistically reacting to higher (and lower) engine performance.
If you use the correct power_scalar e.g. 1.13, you get the engine/plane performance for 1360hp. At 1.23 you get 1480hp and...you guessed it...375mph at approx 9500ft.
This is the section/line you are looking for in the cfg file
[piston_engine]
power_scalar = 1.00 //1.00_1200hp 1.13_1360hp 1.23_1480hp
Have fun
Bernt
If you use the correct power_scalar e.g. 1.13, you get the engine/plane performance for 1360hp. At 1.23 you get 1480hp and...you guessed it...375mph at approx 9500ft.
This is the section/line you are looking for in the cfg file
[piston_engine]
power_scalar = 1.00 //1.00_1200hp 1.13_1360hp 1.23_1480hp
Have fun
Bernt
Here are some new screenshots of my repaint of NL540TP. I 'think' its done, and when uploaded I'll be including a minor update for my "Little Jeanne" repaint as well.
Great work John - a must have for the hangar!
FentiFlier1
Charter Member
I am having as much fun with the P-40N as I had with the A2A P-40B. I am generally very impressed with the care that went into this production. :salute:
Just two points I would like to mention -
1_the high MP/rpm sounds: the loop is too short and gets annoying. (something I can mod myself in fact)
2_I would really appreciate a description of each plane in the "aircraft description" box, i.e. engine, production series (exP-40N-5-CU), history, etc... That would improve the "study sim" aspect and help people understand what is what.
By the way, all the P-40 Mike modelled had the 1200hp engine, right? I remember reading that the 1360hp engine reappeared on the very last factory runs (P-40N-40-CU)
A good description of variants: http://www.p40warhawk.com/Variants/P-40N.htm
Owen.
Just two points I would like to mention -
1_the high MP/rpm sounds: the loop is too short and gets annoying. (something I can mod myself in fact)
2_I would really appreciate a description of each plane in the "aircraft description" box, i.e. engine, production series (exP-40N-5-CU), history, etc... That would improve the "study sim" aspect and help people understand what is what.
By the way, all the P-40 Mike modelled had the 1200hp engine, right? I remember reading that the 1360hp engine reappeared on the very last factory runs (P-40N-40-CU)
A good description of variants: http://www.p40warhawk.com/Variants/P-40N.htm
Owen.
fsxar177
Long-Time Enthusiast
Just tested a few items. The aerodynamics/engine/prop combination is not specifically tuned to achieve the correct performance only at a specific hp setting, it's realistically reacting to higher (and lower) engine performance.
If you use the correct power_scalar e.g. 1.13, you get the engine/plane performance for 1360hp. At 1.23 you get 1480hp and...you guessed it...375mph at approx 9500ft.
This is the section/line you are looking for in the cfg file
[piston_engine]
power_scalar = 1.00 //1.00_1200hp 1.13_1360hp 1.23_1480hp
Have fun
Bernt
Appreciate it Bernt. Going to wait for the update link from Mike, and we'll go from there!
- Joseph
fsxar177
Long-Time Enthusiast
When they reference 1,200, it's the T.O. (take-off) rating at sea level, not the WEP (57") number that we've been discussing. 1,200hp T.O., 1360hp WEP At sea level. Hope that clears it up on the -81.
- Joseph
It's not that easy or clear. Some of the P-40N manuals I have mention a 'theoretical' max MP of 57" but an actual max throttle capability of only 52" (take off maximum 1min) and 45" for normal take off (5min) and maximum climb(5.5min).
That's with grade 100 fuel. The maximum with grade 91 fuel is 47"
That's with grade 100 fuel. The maximum with grade 91 fuel is 47"
fsxar177
Long-Time Enthusiast
I can understand that.
FentiFlier1
Charter Member
@Joseph & Bernt:
Interesting information, didn't know that!
Being an atmospheric engine, I suppose the specific air pressure on a certain day would influence power rating just as for cars?
Had to ask, sorry if this is making the threat go off on a tangeant...
Interesting information, didn't know that!
Being an atmospheric engine, I suppose the specific air pressure on a certain day would influence power rating just as for cars?
Had to ask, sorry if this is making the threat go off on a tangeant...
fsxar177
Long-Time Enthusiast
Yes and no...
As long as the aircraft can make xx amount of boost, based on atmospheric conditions and altitude, it will. Now depending on the aircraft, that number may be limited in many various ways. The big reason for 'holding back', is detonation. Hence the big caution, and 'time limits' such as max 5 minutes, etc, etc. In this case, the engine does not have ADI (water/alcohol injection), so it suffers greatly simply because the 100 octane, or whichever fuel available, has too fast a burn rate, which with more boost can mean severe detonation. The water injection (often used to achieve WEP specs on other aircraft) is what gives the higher octane rating, and hence allowing more boost.
More boost = more power. However, it does not mean more thrust....
Propeller type, design, and gearbox ratio will dictate the efficiency in which that power can be translated into energy.
Now, on top of that... the engine may or may not make xxxx amount of horsepower all the time at xx boost. The engine will run better in a moist, cool environment.
If you want to compound the whole thing...you'd have to throw in the study of propeller efficiency, based on atmospheric conditions and altitude, as well.
The reason why the P-40 examples that we've been referencing make more power up higher, is because with the single stage supercharger, set up for let's say 9,200ft, will allow the engine to produce the same level of boost as it does at sea level, at the 9,200ft. At altitude, the trade off of between density, mixture, and temperature...as well as humidity, and other factors, may allow the engine to run more economically, and more powerful, with yet the same boost settings. Of course, propeller willing, this translates into more speed, which snow-balls into more power... (for many other reasons!! Including, but not limited to ram-air)
All good things must come to an end, and above an altitude for which the supercharger cannot compensate, boost, and thus power begin to rapidly deteriorate, and falling close behind is once again, top speed.
The age-old question, what would a two-stage supercharger do for the P-40? Hard to say. However the War Dept. had many more gripes with the aircraft, than just speed, and high altitude performance. The design was quickly becoming obsolete. The Q model P-40 was the last-ditch effort by Curtiss to produce something to compare with Republic, and North American. But similarly to Lockheed, it was too little, too late. This is often blamed on the Allison, by the casual observer, while the Rolls Royce V-150 Merlin is awarded the victory. The reality was, the Rolls Royce was just that...a Rolls Royce. It became very powerful, yes. But required much more field maintenance, and was already being used up by the other designs. Had the war continued, and development of the G series V-1710 was able to reach a zenith, we would have seen either new and improved designs, or adoption of the Allison(s) into other platforms. Being behind in the jet age, it would have been the late model Allison's and the Pratt & Whitney 28 cyl. 4360 that would have lead the Air Force, and Navy fleets into the late 40's.
- Joseph
mike_cyul
SOH-CM-2025
The updated P-40N packages have now been sent. Paying customers should be receiving an email containing a download link to the new installer. If you purchased after July 30, you will not be receiving the email, as you already have the latest version. If you purchased before July 30 but don't receive an email with the update, please let me know via the support email address (for example, there are presently two email address which have bounced back as undeliverable).
If your .air files are named P40N_sp1, you have the latest version of your package.
Important! Don't forget to uninstal the old package before installing the new.
The updates contain some model fixes, plus the latest flight dynamics.
I'm still working to see about changing the higher-end rpm sounds to better reflect rpm changes, and if successful a new sound file will be sent to customers at that time.
Thanks!
Mike
If your .air files are named P40N_sp1, you have the latest version of your package.
Important! Don't forget to uninstal the old package before installing the new.
The updates contain some model fixes, plus the latest flight dynamics.
I'm still working to see about changing the higher-end rpm sounds to better reflect rpm changes, and if successful a new sound file will be sent to customers at that time.
Thanks!
Mike
