Is there any way to increase an aircraft's range? Help please.

Captain Kurt

Captain Kurt

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Is there any way to increase an aircraft's range? Help please.

The P-38's - stock and Copley's - just can't reach the targets that the real aircraft could. In fact, not even close. It's a major obstacle in a campaign I am developing and I haven't been able to find a fix. Halfway to the target my AI drop out of the sky and the player aircraft can't get much further. In the real world these targets were well within the reach of the P-38.

I admit I don't know what I am doing; I've tried everything I can think of with no joy. Fuel management in the game doesn't improve consumption enough, increasing fuel carried in the air file has no effect, using larger drop tanks has no effect. WTH?

Where is the fuel consumption / range set in the game, and can it be changed? C'mon gurus !! Someone must know this answer ?????????

Cheers
 
Reply...

Okay guys,

I've taken a cursory glance at the airfile in Air Wrench and have come to the following conclusions...

1) At least for the P-38F, she's about 10-15% overpowered. That would have a modest effect on fuel consumption, but I don't think that's enough here.

2) She's also about 700-800 pounds heavy.

3) The engine data for the Allison looks relatively correct, no major problems there. (Though the critical altitude seems really high to me...)

4) The P-38F has a 600 gallon total fuel load (300 internal, 300 external) which should give her a range of about 700 / 1,400 miles, give-or-take.

The P-38 seems to be short just under 475 miles in range with drop tanks, and about 215 miles short without externals. I can see why you're having problems!

I'm afraid I'm a bit tired to start on this tonight, but we'll see what tomorrow brings.

I'm using this site for research data: http://www.wwiivehicles.com/usa/aircraft/fighter/lockheed-p-38f-lightning.asp

Now...a question for Captain Kurt...what are you manifold pressure settings and altitude for this mission? Such information is critical when calculating range...
 
Rami said:
Okay guys,

I've taken a cursory glance at the airfile in Air Wrench and have come to the following conclusions...

1) At least for the P-38F, she's about 10-15% overpowered. That would have a modest effect on fuel consumption, but I don't think that's enough here.

3) The engine data for the Allison looks relatively correct, no major problems there. (Though the critical altitude seems really high to me)...
Click to expand...

Rami, take another glance at the number of prop blades per engine -- two !!! That can screw up the accuracy of all your engine data and range tweaks. For whatever reasons, all stock CFS2 aircraft -- multi and single engined -- were cursed with this two-blade malady, as are most addon models too. Its an obscure defo setting that's easily missed, yet it carries so much weight in its contribution to performance efficiency. The designers must have overlooked this in constructing the P38F FDE, which might explain the need to overpower the engine dynamics, compensating for the weak airscrew they either weren't aware of or just didn't connect the dots. Before you can tweak anything related to power and range on any prop model, you have to correct this first for best results.
 
Whoa, I gotta find that tool. It looks so much more capable than AirEd. Where is it available?

The two blade prop is a revelation. I have to try tweaking that.

I am using the Gryphon P-38L-5 for these LR missions. I have the fuel leaned out to where it almost stops running and am pulling 40 inches manifold at 2000 rpm. Most of the mission is at 18,000 to 19,000 feet ASL. This only gives me about another 50 to 75 miles versus auto management. With full internal tanks (500 gallons) I can make about 350 miles.

Cheers
 
Yes, Captain, Airwrench is an excellent tool. Is payware from www.mudpond.org , just 20$ gladly paid if you're into tweaking planes flight dynamics.

Rami, your range estimation in Airwrench has been made at sea level and full throttle. Try a cruising altitude and a somewhat lower manifold/RPM. I did it in my P-38F (with 1225HP Allisons) and got a range of 1520 miles with 600 gallons of fuel.

Then, if you think your Lightning is still reaching too far you could tweak the fuel consumption in the Fuel tag. I've never used it, though.
 
JapLance said:
Yes, Captain, Airwrench is an excellent tool. Is payware from www.mudpond.org , just 20$ gladly paid if you're into tweaking planes flight dynamics.

Rami, your range estimation in Airwrench has been made at sea level and full throttle. Try a cruising altitude and a somewhat lower manifold/RPM. I did it in my P-38F (with 1225HP Allisons) and got a range of 1520 miles with 600 gallons of fuel.

Then, if you think your Lightning is still reaching too far you could tweak the fuel consumption in the Fuel tag. I've never used it, though.
Click to expand...

The great problem is that no one remembers to put the engine at the RIGHT mix to long range flight...

Cheers

Pepe
 
Reply...

Bearcat,

Once again, I bow before the master. Where would prop blades be in AirEd?
 
Wow - I don't remember seeing that working on the Superfort - which had 4 bladed props! And I scoured the .air file with AirWrench - I will have to go back and check!
 
Reply...

Does anyone know what the "Lindbergh settings" were for the P-38? I know that it was 1,600 RPM, but all I can find is they were to be run at a "high manifold pressure."

Well....what exactly is "High Manifold Pressure"??

Numbers would be nice...
 
Rami said:
Does anyone know what the "Lindbergh settings" were for the P-38? I know that it was 1,600 RPM, but all I can find is they were to be run at a "high manifold pressure."

Well....what exactly is "High Manifold Pressure"??

Numbers would be nice...
Click to expand...

Well, according to your own researched air file data in post #3, the first pic shows a max in hg of 54. So 54 inches of mercury is the high MP figure you're working with in your posted example. What Lindberg prescribed exactly is anyone's guess, but you already have a baseline in your own air file to work with.

Here's some more revelation gained from my own research: "The manifold pressure gauge is really NOT about pressure but about suction! Think about it. Your whole engine (especially the cylinders) is a big vacuum pump. Every time the piston drops into the “intake” stroke it is literally pulling or sucking air into the cylinder. Your manifold pressure gauge is actually reading suction not ram air pressure. That’s why at idle power your manifold pressure gauge might read 10 or 12 inches when the outside ambient pressure is 30 inches. Your engine is literally starving for air! It is creating a vacuum or negative pressure inside the intake manifold.
The induction system of couse being the air / fuel mixture that is between the throttle and the cylinders.

This measurement, which is read in inches of mercury or “in hg”, is one of the best methods to determine just how much power is being developed by the engine. The more air and fuel we can pump or pull into the cylinders, the more power the engine can develop (which makes us fly faster). When you can measure how much air pressure is in the induction system, just before the air / fuel mixture enters into the cylinders, you will have a good idea of how much power you are developing.

In normally aspirated engines (non turbo-charged), the manifold pressure gauge has a range of anwhere between 10 – 40 in. hg (or inches of mercury). In a turbocharged engine, the manifold pressure is allowed to go as high as the engine manufacturer allows. When the engine is shut down, the manifold pressure gauge should read very close to the current atmospheric pressure setting."

WRT your number of props question, in pic #3 of your post #3, the number of props per engine can be set in the second column from the right topped by Prop Diameter -- you want the bottom box in that column.
 
Rami said:
Does anyone know what the "Lindbergh settings" were for the P-38? I know that it was 1,600 RPM, but all I can find is they were to be run at a "high manifold pressure."

Well....what exactly is "High Manifold Pressure"??

Numbers would be nice...
Click to expand...

As I remember from a book about Lindbergh, his settings used very poor mix, low revs and maximum prop pitch. According some theorics this could blow up the engine.

Cheers

Pepe
 
Reply...

Well,

Asking what manifold pressure is was a poor choice.

I know what it is, what I was specifically asking for what the actual manifold settings that Lindbergh used. The use of the word "high" doesn't cut it for me, I need specifics.

And Bearcat, adjusting airfiles in AirWrench can produce crazy results. What I usually do is look at the file in AirWrench and then use AirEd to fix it.

I'd rather find the information in AirEd and fix it that way, then tweak it with Air Wrench.
 
Rami said:
And Bearcat, adjusting airfiles in AirWrench can produce crazy results. What I usually do is look at the file in AirWrench and then use AirEd to fix it.I'd rather find the information in AirEd and fix it that way, then tweak it with Air Wrench.
Click to expand...

Yeah, i agree -- think we had that discussion before back in your "air file roundup" days. What i've found that works best for tweaking CFS2 models in AW is to complete all mods with AW, save the work in the proggy and exit, then hand edit the aircraft.cfg. I strip out all unnecessary FS-style data below the top [fltsim.X] header section except the following:


[General]--------------------------------------optional, i use this to keep a technical overview description
[weight_and_balance]--------------------useful but not critical
[flight_tuning]--------------------------------useful but not critical
[piston_engine]-----------------------------very important for maintaining the engine tweaks
[propeller]-------------------------------------same, but also retains the number of props data from the air file
[TailHook]-------------------------------------critical
[exits]------------------------------------------useful
[contact_points]----------------------------critical
[Views]-----------------------------------------critical
[LIGHTS]---------------------------------------critical
[Reference Speeds]-----------------------optional
[brakes]----------------------------------------good place to tweak brake scalar and differential braking which also aids AI in landing and ground handling
[stall_warning]-------------------------------optional
[electrical]-------------------------------------optional, but sometimes helps with some starting issues
[flaps.0] //Trailing Edge Flaps--------useful for maintaining effects of complex flap mods
[forcefeedback]------------------------------optional

In the air file, i hand edit only records 1,2 and 3 in AirED for CFS2 formatting. Everything else stays as AW left it.
 
Captain Kurt,

I got thinking about this so I tried an experiment, first I looked at the checklist for the 1% P-38F which contains this little nugget of info:

---------------------------
CRUISE (BEST RANGE)
Throttle 28.2 in. Hg.
Prop set to 1,800 rpm
---------------------------

So, I plugged that info into AirWrenches flight endurance estimate calculator @ 10, 20 & 30 thousand feet. Best range was @ 20 thousand. This may not be perfect or optimal, but should be a good start. See attached screen shot.

Boatz
 
Back again,

Well I just tried with the above (28.2inHg X 1800 rpm @ 20,000 ft) and here is what I got:

Bone stock P-38F = 31.04 GPH @ 127 MPH IAS
1% P-38F = 43.61 GPH @ 167.4 MPH IAS


= a very, very long flight


Boatz

PS: Your mileage may very!
 
No Soap

Shoot.

That all seems to calculate out on paper but doesn't work in the game. Using the parameters of 28hg, 1800 rpm, leaned out to max and 20000 feet I was able to do 398 miles on internal fuel and 611 miles with 150 gal tanks. That is 1.3 gallons consumed per mile!!

I tried this several times and got the same results.

I'm going to try AirWrench and see of changing the props to 3 blades makes a difference.

OK just did that, distance decreased by about 30 miles. I tried specifying bigger drop tanks 308 gallons versus original 150. Ne effect at all, same distance.

Now tried it with full throttle, max rpm and full rich. I made it 10 miles further than managing the throttles.

Finally I tried it with auto fuel management enabled. Same distance.

Everything stays within 10 - 15 miles plus or minus.

It looks like something is coded in somewhere that sets the distance. Everything else has no effect, which it would if there wasn''t a limit set somewhere.

Incidentally all test are done using warp. If you were willing to fly a 7 or 8 hour mission in real time, by hand maybe the outcome would be different. That hardly matters since no one is going to actually do that.

Cheers
 
Incidentally all test are done using warp
Click to expand...

I'm afraid here's the problem. I've read a few times in these forums that fuel management while warping doesn't work in CFS2 :isadizzy:.

An alternative could be using the Time rate. The standard CFS2 allows 4x, but with CFO_Weather higher rates can be used.
 
Yes, I think the only realistic option is to use CFO weather, which will let you do up to 64x time compression. Only problem is with autopilot, you're limited to 4x compression. I would really love to be able to increase that, but have no idea how or if that can be done. The B-29 project I'm working on involves 15 hour missions - even at 4x, that's a long haul.

Other options: don't use autopilot - you can have a reasonable level of control over a well-trimmed aircraft at up to about 16x compression, and fly her just making trim adjustments.
alternatively, use the CFO refuel/dump gauge, cheat a little, and do an "air to air refuel" a few times as needed during a mission. From a mission builder standpoint, one could have messages pop up when you reach an area such as "refuel 100%", telling the player that it's okay to do that 'cheat'. Then at the last refuel point, say "refuel 20%" or whatever, to leave a realistic amount of gas in the player's tank for the last leg of the flight, which is what really matters.

Anyway, I have been struggling with the same issue - B-24 Guy thinks it's simulated by fuel weight instead of volume. Even at that, there still seem to be some range limitations hard-coded or something. I just hate to use unlimited fuel on a long mission when fuel management is one of the biggest challenges of the thing.
 
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