True Altitude?

[Soldier_Fortune]

Hi all!

Jeremiah: I am an experienced engineer also, but that is not relevant here. However, since we have the same profession, we certainly must share the basic concepts about Mathematical Calculation.

Regarding your question about the 100,000 figure. It is NOT a measure of any distance or altitude. It's simply a mathematical value that let's you know you are converting the altitude to a decimal to be used in the equation.

1) The calculation rules are rigid and do not allow exceptions.

2) It is not allowed to transform arbitrarily an absolute amount into another relative: for such a transformation to be valid, the absolute amount must be refered to another which can be considered as a basis or reference in a consistent manner.

Thus, you are not free to transform "4850 meters" into "0.0485 p.u." (or "4.85%"), because always you will must answer the immediate question: "0.0485 p.u. (or 4.85%) of WHAT?"

Also, why are you using a Crimea map? Remember, in the scientific method you need to establish a control group and establish some baseline figures. To do that, you need an ISA neutral map (15 deg C) that allows bombing at sea level. There were only a couple of maps that allowed that; Gulf of Finland 1 and a generic Island map. The Crimea map is 25 deg C which is 10 deg C above ISA and you would need to factor in the difference in density altitude...which can be done with my equation. (But I haven't revealed how yet.)

And, why are you using a chart which returns TAS for (roughly) 25 ºC @MSL, with a map of 15 ºC @MSL?

If you are looking for a good method to find the in-game IAS/TAS relationships with any map, I could suggest you to fly a B-25J: it has IAS/TAS and OAT gauges, and altimeter. These three instruments are all you would need to see differences and matches of TAS for different altitudes and thermal conditions. This aircraft perfectly could serve as the control case for your research.

Also, with regards to me perhaps over-complicating things, I'm actually attempting to do just the opposite. Take a second and look up the wiki article on the E-6B (whiz wheel) calculator. See the equations? For me, those are quite manageable...they're basic trigonometry. Something I have to use every day. But I don't think most players would enjoy number crunching them on their way to a target.

Waht the wiki's article shows about E-6B are the equations to solve the 'triangle of speeds' in order to find Ground Speed and True Heading when there is any wind. Those equations may be solved mathematically (applying the Theorem of the Sins), or geometrically (drawing the vectors of a/c's and wind's speeds in a given scale, and then measuring the modulus of the resulting vector with a ruler, and the angles with a protractor).
The back side of the E6-B returns GS and TH in few seconds, solving the triangle of speeds in only two steps, and avoiding to use complicated equations.

The front side of the wizz wheel is designed to obtain TAS from IAS (among many other calculations), regarding of the OAT and altitude, in one step and no need to solve all and each of the ISA equations.

Perhaps it's needed to define what the E6-B really is: It is an Analog 'Flight Computer'.
An Analog Computer (it is not the matter if it is an electronic or mechanical analog computer) is programmed by hardware. Therefore, it can only do that for which it was designed and built, and it must be considered a "specialized" tool.
The E6-B basically is a circular slide ruller, but specially designed to perform flight calculations in the easiest and fastest manner as possible.

Of course, today we can find apps like 'Pilotwizz' (this is only for iPhone), or 'FlightTools E6-B' (it is for Android and iPhone). But the usage of a smartphone or a programmable calculator while I'm flying an IL-4 over Eastern Prussia in 1944, is not realistic (and therefore funny) for my taste.

Also, I don't think the numbers my equations are coming up with are the actual TAS of the aircraft, it's just the numbers the game is using to drop bombs. I'm thinking they have taken "special liberties" with Newtonian physics (classical mechanics) in the game and that bombs don't precisely follow established flight paths based on actual physics.

Mate: I've been testing all sort of bombers, maps (my lattest tests were performed just with both Finland maps), and winds. The result is expressed in the charts I've attached to the post #30.
I've achieved accurate hits using manual targeting & drops.

I don't think that TD have taken such "special liberties" with Physics. If they were done something like that, it should affect in-game all what is related with the flight, in the same way: take-off, landing, cruising... and level bombing.
But if you hit the Autopilot during one of your bombing missions, and then watch how the AI does the task, you will see it is not able to perform a decent level bombing, even an AI pilot with the best skills.

IMHO, many improvements were introduced since the 4.09 patch until today: FM, beacons, temperatures, winds... And it seems something was missed or forgotten about level bombing and bombsights, along the patches.
The fact is neither the Norden/Lofte type BS nor the OKPB-1 type work as it is supposed to do... as if they were uncalibrated.

Thus, IMO, if I must do calculations by myself to get certain accuracy, then I prefere to calculate directly the BS elevation angle for manual drop, instead of calculating how to compensate for a poorly calibrated automatic bombsight.

Anyway, if you can, please let me know what you find out using an E-6B on an ISA neutral map. I am curious about that.

As I said earlier, and as I've said in every post of this thread, I've tested many maps, with all the actual level bombers, at diffeerent altitudes. Taking in account the historical accuracy of pin-point high level bombing during the WW2 (less than 20% of bombs fell on their intended targets along the war), I've obtained a more than acceptable accuracy, always using manual targeting.
The most of data for my calculations were gathered in-game: altitude, IAS, heading, OAT. And, with the B-25J, the TAS was read, not calculated.

My tests included:
1) The lapse rate of OAT measured with different OAT gauges (The ISA model was confirmed in-game for all the tested maps).

2) The TAS regarding OAT and altitude (This was calculated with the E6-B and with the ISA equations, and measured with the TAS gauges of Me-262 and B-25J. Measurements match calculations, for different maps).

3) The accuracy of level bombing using manual targeting, in differents maps with all the bombers, but with no wind.

4) The accuracy of level bombing using manual targeting, in differents maps with all the bombers, but with winds: tail wind, nose wind, cross wind, any wind direction and any wind speed. (This confirms: the need of to calculate the Ground Speed and True Heading to mantain the True Course approaching to the target; the need of to use the + or - side slip angle of the bombsight to compensate the angle between True Course and True Heading; if not, the bomb will fall far from the target confirming the effect of the cross wind on the free fall bombs. True Heading, Ground Speed and Compensation Angle were calculated with the back side of the E6-B).

The atmosphere now is better mdeled, but humidity and true altitude are not included (by now). Anyway the atmospheric model involves the aircrafts' behavior: take-off, landing, flight, engines heating and endurance, max payload, speed, fuel consumption, trimming, altitude to engage/disengage superchargers, altitude to change the air/fuel mix... and a long etc.

Would you like to see one more test with the Gulf of Finland_summer map, anyway?
OK: when I return home next week, I'll do that test, and then I'll try to do a .ntrk to show how accurate may be the manual targeting.