u/dedarkener

https://preview.redd.it/w0f5nl9sxfih1.png?width=1155&format=png&auto=webp&s=d1a708c90e7055f1192412ca8a469c30acedaa8e

As mentioned in the broadcast, IFT13 did not throttle back as much or as long as IFT12 for Max Q. Acceleration dropped from ~1 to ~0.8 g for ~5 s, then started ramping back up over the next 10 s. For previous flights, the reduction started around 0.6-0.7 g, and extended at least 15 s before ramping up again.

Max acceleration for the booster was about 2 g, same as IFT12 - makes me think it's a programmed limit, since IFT12 was missing one engine.

The IFT13 ship repeated IFT12's flat acceleration for the first ~90 sec after hot staging. Maybe they are limiting the max g until the fuel load drops below some level, to limit structural stress? It also looks like they throttled back at the end, as in some earlier flights (but notably not in IFT10).

The blip just before 30s is an artifact from the video - possibly the telemetry from the ship dropped out for a moment. There were a few of these in IFT12 as well.

This data is simply calculated from change of speed reported from the video telemetry. Gravity is not included in the calculation. The altitude profile was unusual, with the ship losing altitude just before SECO, and I couldn't fit it to fill in the data missing from the new telemetry graphics, so I left off the gravity vector.

IFT12 acceleration off the pad was initially faster than IFT10/11, similar to IFT6, but started to outpace all after 30 s. They throttled the thrust way back, almost half, for max Q, but then found another gear, rapidly increasing to 2 g (could have been more if not for the loss of 1 engine) until hot staging. Unfortunately, with the new status bar layout, there's no booster speed display for about 80 s after hot staging, so can't see if there was a negative jolt that could have contributed to the boost back failure.

The ship started fast, then dropped to around 0.5 g after losing one RVAC engine. Looks like maybe they monitored the situation for about a minute, then throttled up the remaining engines, eventually hitting a peak of about 4 g at the end of the burn. No evidence of limiting the thrust at 3 g, as appeared to be the case on some earlier flights.

There are a couple of glitches in the data, due to unusual behaviour in the video telemetry, most noticeable at 68 and 437 s. It's weird - the T clock stops, but the other telemetry values continue to change, spooling down slowly, then speeding up when the clock restarts. They may be running a rolling average smoothing filter on the displayed data, but not the clock?

This data is generated by grabbing screenshots of the video at a rate of about 5 per second, running an OCR script to extract the numbers, and then calculating the acceleration by a simple change of speed equation. I fully acknowledge that I am ignoring gravity, frames of reference, and other important considerations. These graphs are for casual interest only - don't use them as reference material for your orbital mechanics project.

IFT13 Acceleration Profile - Reduced Max Q, Repeated Ship G Limits

IFT12 V3 Hardware Definitely Faster