Victory205

It is amazing to see the difference in mindset. There is a reason I say that “ego is the enemy”. The goal is not to be right, it’s to find the accurate answer. Pretty easy to see the effects of “you don’t know what you don’t know”, and how people who presuppose outcomes are a waste of time. When flight testing, every instrument is calibrated before being used for data acquisition. Does anyone here know the basic means of verifying something as simple as airspeed? Hint, it doesn’t involve asking a vendor if an instrument is “accurate”.

Don’t forget runway slope. What are your acceptable distance parameters? Ten, fifteen feet or so?

Lots of interesting information in the publication concerning turbojet performance considerations, high speed flight dynamics, including Mach effects, stability, etc. We used it as a base document for advanced strike aerodynamics. Everyone should have a copy sitting on their shelf.

You’ll need to provide OAT, Pressure Altitude, Gross weight, CG, flap position, mil or max (I recommend FF and Mil for granularity) and rotation speed for takeoff distance. Landing distance assumes speed brakes and spoilers extended, DLC in use, 15 unit approach AOA, anti-skid on, but do not include aerodynamic braking using the stabilators. Add 40% for no speed brakes no spoilers.

Doesn’t extend the takeoff distance. Wonder why? It’s almost like, I dunno, someone did something to make the peanut butter and jelly come out even? What is the landing distance for say, a 45,000 F14A using normal braking, zero wind, standard day? How about max braking?

If you pay attention to the Climate Change Doomers, not only is it possible, it’s inevitable…we’re always ten years from complete, utter disaster. It’s going to require longer runways and longer wings, that’s for sure.

Short answer on the “burble” is that I don’t know. It may end up being aircraft specific as well. There are two aspects, the flow over the deck and the wake of the island, both nuanced and dépendant on the strength of the natural wind, which dictates weather the apparent wind direction is axial or down the angle. Axial winds produce a disturbance from the island which is more of an annoyance. Stronger natural winds move the balloon/sink farther from the ship, and make it more pronounced. However, under those conditions, the pilot is up on the power a bit, which makes the engine response quicker. A PC desktop sim makes all of this difficult to notice. To get comfortable with the T45, I’d advise flying a higher pattern for awhile, to get a little more groove time to experience flying the ball. Maybe try 800 to 1000 feet MSL, and extending downwind. You don’t need to be wider, just farther aft of abeam before you start your turn. The T45 holds AOA fairly well, and I just haven’t had issues hook skipping. It is important to fly the ball to touchdown, meaning continuing to look at the mirror until touchdown and making corrections. A rising ball will tend to result in bolters.

Density altitude is pressure altitude corrected for non-standard temperature. The short answer, is that it affects lift, including within the engine, which reduces thrust. I am not typing up the formulae. Think of the effect of temperature on takeoff performance of a jet, even at a constant pressure at sea level. Grab yourself a copy of Aerodynamics for Naval Aviators. It’s all over the net in pdf form. Lots of information there, starting on page 2.

Who is that? Should I be impressed?

A higher temperature requires a higher speed to reach a given Mach number. Mach varies directly proportional to temperature. The warmer the air, the higher the speed of sound. On a standard day, the speed of sound at SL (15C) is 661 knots, at 36,000, the notional height of the tropopause (-56C), Mach one is 573 KTAS. In your example, you increased the temperature dramatically at altitude, making the speed of sound much faster, reducing the ratio of actual velocity relative to the speed of sound. Mach is a ratio.

Not quite sure what you’re getting at, unless you are attempting to “set the hook” by increasing the attitude, but setting up the ship at 15 knots and a natural wind of 5 knots to result in around 20 knots of closure, and simply flying on speed all the way down, with a centered ball on the mirror results in consistent arrestments. You don’t want too much wind and you don’t want to fly a low ball, both of which result in a flatter approach and are self defeating for your purposes. There is a tendency to settle in close, and get over powered and flat as you cross the ramp. You have to get the power back off to keep the ball centered and stable when you hit the deck. Keep flying the ball.

Simple test would be to map the trigger to a different button, or even a key press (turn the key repeat rate way down on your keyboard settings).

It’s the low speed directional stability that is poorly modeled in most modules. There is a lot missing that only HB has addressed, but some level of familiarity with aircraft handling is required to appreciate. It’s understandable that people focus on minutia like taxi or lighting, they don’t have the background to understand the magic. What isn’t acceptable is the attitude from too many people. Some folks just enjoy conflict and misery. How do you know if the F16 is accurately modeled? The factual answer is you don’t, and are engaging in a Mk One Mod Zero trolling expedition. Don’t waste my time further.

He’s got a point. We’re a bunch of dupes to partake of this sim because of taxi rolling performance. Maybe iRacing would sell DCS their tire model? Of course they’ve been mewling about that for a dozen years over there too! Does the directional stability issues on the F5, F18, P51, P47, FW190, Bf109 bother you at all? The F16 flies like an A320, but at least it rolls at idle thrust. At least I think it does. I just do whatever it takes to get to the runway, which isn’t something I do very often anyway. I don’t want any more taxi time.

Really? Actual movement of what? Do you understand the calculations required to simulate KIAS? Have you verified it is accurate or is this essentially a guess? I have been testing on a standard day over the past week, in a mission with zero weather and no winds. About 30% of the time, I had wind velocities up to 122 knots. Where did that come from? The point is to put the egos aside and get the model correct.

Makes me chuckle to recall that we had a Level D 757 simulator, certified by the FAA, that would track straight down the runway while you yawed it ±20º from centerline. Took about a decade and a half to address it in a multimillion dollar upgrade, which included a new visual, and it still wasn’t quite right. Good enough for flight training. Must say, I’ve never heard anyone so interested in taxi before.

Honest Broker- A) How would you know? B) Let us know when you find one.

I can't fly a ball and a half low! I'd have nightmares of angry LSO debriefs! One thing to keep in mind as well, the ball needs to be stable on the mirror as you touch down. If you are on speed and see a rising ball over the deck, good chance that you'll bolter in a lot of aircraft. If you try to stop it by dropping the nose, same result. I like the way the T45 lands. It's challenging, a good trainer.

Do you have anything more than a “hunch”? Is there a way, especially for those with a keen focus on performance, to ascertain the accuracy of the various available indications of velocity in the sim? Your testing and subsequent decrees were all based on a hunch? Growing up in a digital world creates biases and complacency. Think.

What makes you believe that the Control Y bar is correct?

Use your Google-fu to find a NATOPS manual online. The drag numbers are there, and in the performance manual. If it takes you more than three minutes, then you should join the Air Force and fly C5’As (not that there is anything wrong with that).

Some performance charts use TMN, some use IMN, and whenever the former is in play, indicator error is an issue. If you look at your manual, you will see significant instrument error in the transonic range. Alpha is another value that has an impact on velocity indications. In other words, determining performance more complex than it may seem at first blush. We don’t have a test aircraft instrumented with a pitot/alpha boom, we have a simulator with algorithms that may or may not model instrument error. I am not sure that the other modules model the sonic shock wave phenomenon on the pitot static system. I will investigate a few of the other modules at some point, time permitting.

Good point.

Don’t anyone do anything yet. Everything is about to change, and other than it’s always good to practice turns, you’d be wasting your time. The point of all of this is to get it right, using valid, objective analysis. Tacview isn’t a workable tool for this in my opinion.

Ha Ha! SHB to a wave off. Classic.