Lightning Speed

[Mig_eater 0]

Does anyone else find the Lightning a little unrealistically slow?

 

I'm hard pressed to get to Mach 2, even at 50,000ft on full power i'm only getting to about 1.5.

 

Any idea why?

 

Tried it on Hard, and Normal flight model...

 

- Alex

[Spinners 15,981]

Out of interest what will a stock (J79) Phantom do at the same altitude?

[Fubar512 1,350]

Possibly overly conservative drag tables, or even a matter of simply not defining a sufficiant number of data points in said tables.

 

I once used NASA data while penning up a modified flight model for the F-104G (TKs CD0 values for that bird were a bit off, which was unusual), as well as expanded drag tables, and voila... The resulting model matched published time-to-speed acceleration tables and low-altitude Vmax figures for an F-104 with the same powerplant. Wrench can attest to that one...

[Spinners 15,981]

For reference, in the game the stock F-4M achieves Mach 1.9 at 15,000m (just had a go). Getting from 1.6 to 1.9 takes ages, even at x8!!!

[Wrench 9,632]

Fubars tweeks to the Zipper are NICE!!! Live up to it's billing as the 'missile with a man in it'

 

You should upload it, Ed. I think the other Zipper-heads would like it!

 

wrench

kevin stein

[Derk 265]

It would be interesting too have a look into the F4 FM at the other side of the scale: most of them are supercruising........

Couldn't get rid of it without slowing it down tot Mach 1.2 at 36.000 ft in max. AB... Same goes for some other planes.

The FM's are tricky bussiness for an amateur like me (fiddled with the engine data and some basic drag values only) and couldn't find that much in the KB or older doc's

 

Houdoe,

 

Derk

[+Spillone104 553]

Fubars tweeks to the Zipper are NICE!!! Live up to it's billing as the 'missile with a man in it'

 

You should upload it, Ed. I think the other Zipper-heads would like it!

 

wrench

kevin stein

 

:yes: indeed.

 

Anyway the stock Exp2 Lighting surprise for its rapid acceleration to mach 1 and without using AB but going above seems to have an extreme drag and basically you'll never reach Mach 2 in clean configuration because of fuel. A bit disappointing.

Even the F-105D is transformed to a dragmaster at least from Exp2. In clean configuration it hardly goes supersonic at low level and at high altitude it barely goes a bit faster.

But the list is long.

[Spinners 15,981]

It would be interesting too have a look into the F4 FM at the other side of the scale: most of them are supercruising........

 

[FlightControl]

StallSpeed=74.00

CruiseSpeed=203.47

ClimbSpeed=348.86

CornerSpeed=253.36

LandingSpeed=67.43

MaxG=8.50

MaxSpeedSL=404.79

MachLimit=2.095

MachLimitDry=0.980 <<<<< I thought this prevented supercruising

PitchDamper=0.7

RollDamper=0.3

YawDamper=0.0

GunBoresightAngle=-2.0

RocketBoresightAngle=-1.0

[Derk 265]

[FlightControl]

StallSpeed=74.00

CruiseSpeed=203.47

ClimbSpeed=348.86

CornerSpeed=253.36

LandingSpeed=67.43

MaxG=8.50

MaxSpeedSL=404.79

MachLimit=2.095

MachLimitDry=0.980 <<<<< I thought this prevented supercruising

PitchDamper=0.7

RollDamper=0.3

YawDamper=0.0

GunBoresightAngle=-2.0

RocketBoresightAngle=-1.0

 

Sure, it's supposed to, but doesn't always work........ Spend hours together with Ravenclaw trying to tame his RF 4's, but we didn't succeed......(or degraded the high level performance too much)

Probably, among other things, it's in the dry Mach tables in the engine..

If anyone can point the right direction I'll be delighted

 

Houdoe,

 

Derk

[FastCargo 412]

Well, remember there are several parameters you need to adjust.

 

First, remember that the [FlightControl] section is mainly for the AI to fly the aircraft in parameters. It does a secondary job of keeping the aircraft within limits through a crude decreasing thrust curve (or pitch down moment for altitude limits) that overrides the charts. I find this can be problematic for aircraft that have limits that are dictated by other than thrust or drag (thermal or other considerations). I tend to raise the limits in the AI section and manipulate the FM tables to get the performance I want (ie I should be able to exceed Mach 1 in dry thrust in a shallow dive, even though I don't in level flight for a particular aircraft).

 

Anyway, speed limits (discounting the [FlightControl] section) are determined by the following:

 

Base coefficients:

 

CD0 - Zero-lift drag coefficient

CDL - Drag coefficient due to lift (induced drag effect)

SLThrustDry - Non-AB Thrust at Sea Level

SLThrustWet - AB Thrust at Sea Level

 

Chart coefficients (used as multipliers):

 

CD0MachTable - Zero-lift drag coefficient multiplier (of CD0) vs Mach number

CDLAlphaTable - Total drag coefficient multiplier vs AOA

AltitudeTableData - Thrust data multiplier for altitude

DryMachTableData - Thrust data multiplier for Mach (Non-AB)

WetMachTableData - Thrust data multiplier for Mach (AB)

 

So, several things we can take away from this:

 

One, speed calculations can get VERY complex, dependent on Mach, altitude and AOA.

Two, and I see this mistake made a lot, reducing CD0 to almost nothing means that even with massive CD0MachTable chart manipulation, your actual drag values simply won't change that much.

Three, AOA can make a big difference, which can be directly manipulated in level flight by weight. An aircraft that can't supercruise at full internal fuel weight may be able to with 25% internal fuel weight, because you need less AOA, because your total lift requirement has decreased.

Four, the resolution of the charts a lot of times isn't good enough. I've been using a standard of 0.1 Mach resolution for the Mach tables, and 1000 meters for the altitude tables...using LOTS of interpolation.

Five, a final recommendation for 'at the limit' evaluation is to jack up the values in the [FlightControl] section real high, so you can get a better idea of how the numbers are really working without any artificial limits interfering...sometimes guys forget and wonder why their manipulations aren't changing anything...

 

For the Lightning, I was playing with it just a little and I think the 2.095 Mach limit is kicking the thrust reduction in a little soon...I've been hovering right at 1.99 Mach at 45k feet. I'd say try jacking the Mach Limit up to 2.2 in the [FlightControl] section to see if that helps.

 

FC

[Derk 265]

I'll put this in my own KB map....

 

Thanks,

 

Derk

[Mig_eater 0]

I just managed 1.9 at about 45,000ft with around half fuel, and no armament... I'm sure you'll tell me i'm playing the wrong game, but I hate tweaking this stuff! All I want is for Britain's mach 2 fighter to do what it says on the tin... is that so much to ask?

 

Perhaps in another patch...

[Fubar512 1,350]

The ceiling value can likewise be a limitation, as it imposes a set value based on an agreed upon rate-of-climb minimum, and it's implemented in-game by zeroing thrust above that value.

[fireengineer 1]

The ceiling value can likewise be a limitation, as it imposes a set value based on an agreed upon rate-of-climb minimum, and it's implemented in-game by zeroing thrust above that value.

I just got the EF2000 model to super cruise via the tips here, cheers

[Siddley 9]

I think the fastest speed recorded in the Lightning was when the Saudi's sent a ( possibly crazy ) test pilot to the UK, in order to check out that the aircraft really was all that BAC claimed it to be, before placing an order for the export model.

 

Despite being briefed on the notional Vmax he accelerated away from his British chase pilot ( also in a Lightning ) who was doing something like M2.2 at 60,000 feet.

 

His comments afterwards were " You British are really honest, your Lightning is even faster than you say it is "

[fireengineer 1]

I think the fastest speed recorded in the Lightning was when the Saudi's sent a ( possibly crazy ) test pilot to the UK, in order to check out that the aircraft really was all that BAC claimed it to be, before placing an order for the export model.

 

Despite being briefed on the notional Vmax he accelerated away from his British chase pilot ( also in a Lightning ) who was doing something like M2.2 at 60,000 feet.

 

His comments afterwards were " You British are really honest, your Lightning is even faster than you say it is "

Did you ever hear the story of an American U2 approaching UK airspace at operational altitude, he was advised to look out for his Lightning escort, he thought 'yeah right I'm at 85,000ft' when a single lightning passed him from behind.... and above! Shot past him supersonic and in a descent. It's not supposed to do that, but after speaking to a former pilot and reading about this, it appears to be a well known event, the Lightning had done a zoom climb from 60k at Mach2 to lob itself over the unsuspecting U2.

[Siddley 9]

I hadn't heard that, but nothing would surprise me much about the Lightning

 

When I was a little kid I used to constantly beg my dad to drive me the 50 miles to RAF Coningsby so I could watch them take off ( climbing out at about 60 degrees in full reheat ) and land.

 

Once I even got a tour of the base thanks to an RAF officer who noticed me standing there at the perimeter fence like the little military aircraft geek that I was.

I didn't give two hoots about the Phantoms which also operated from there at the time, I just loved the Lightning.

 

It's probably a good thing that I didn't realise that the Lightning's low fuel warning light came on as it was taxying out to the runway, that it only had two rear aspect heat seekers which were unproved in combat and it required more maintenance than the race tuned 1950's Triton motorcycle I would own 20 years later

If so then I would have doubted our ability to prevail in the Cold War

[crl848 9]

It's probably a good thing that I didn't realise that the Lightning's low fuel warning light came on as it was taxying out to the runway, that it only had two rear aspect heat seekers which were unproved in combat and it required more maintenance than the race tuned 1950's Triton motorcycle I would own 20 years later

If so then I would have doubted our ability to prevail in the Cold War

 

And limited to 6g or less depending on various parameters, so its turning circle was rather large...