Thank you for the correction. I'm researching quickly what Google AI seems to be saying, but isn't telling me their sources.
Probably should have clicked on, and read, your source. It quite clearly stated it was for the solid rockets of the STS.
I assume you agree that the "350 msec increase in thrust pressure" from Braeunig was bogus (or if/when it does happen, is near negligible), and that no one else is saying this, or has ever said this.
Why would I agree? You haven't shown that this wasn't the case, or that it is not possible. Looking at your GDocs, your only comment is "No", that's it. No comparison, no numbers we can look at, nothing. I get enough unsupported claims from Rasa.
Here's another PDF that shows thrust taking some time to build up.
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With a graph for liquid hypergolic fuels that again shows a build up of thrust, but this article doesn't cover "Combustion chamber pressure" which I believe is what Braeunig was confusing with thrust pressure.
Except the graph you are looking at shows an initial build up to about 90% in about 0.02s, a drop to 60% in the next 0.02s, and then a rise to 100% before the 1s mark. So a sudden impulse, followed by a steady burn.
Here's another paper on Liquid Rocket engines, showing a build up of thrust:
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From this point on, it becomes dishonest for PNA's to present Braeunig's unsupported, vague, and retracted claim as their "explanation" for how Apollo's AM launches were all approx 2.5X too fast.
Oh, how lovely, a generic graph with no details is your evidence of impulse, oh joy, well, colour me convinced.
And Braeunig's initial point was on the time to orbit for the ascent stage, NOT the immediate acceleration after launch. His later addition posed the possibility of an additional impulse from over pressure. And as you have previously established, possibility is all that maters, so no, we wont be dismissing Braeunig at all.
The final argument for "lower thrust at ignition" is provided by NASA's simulation of the "fire plume" for the first 0.7 seconds, which suddenly (and unrealistically) just disappears in a single frame, leaving behind a fully dark Lander base platform, as though the A-50 combustion just 1 meter above it isn't producing any light onto it...
Where have you established the camera's were at a sufficient height to see the top of the descent stage, and thus determine if they were lit up at all? In addition, how many lumens was being provided by the ascent engine, and would we expect to see a difference (capable of being picked up by the rover's camera) in the bright, daylight conditions?
We have a 1997 example of Titan IV which uses A-50+N2O4 for it's 2nd stage, firing at night from 550 miles away at 120 miles altitude (a virtual vacuum) and it's shining very bright.
And we're also looking up the business end of the rocket, and so we can see the ignition chamber. Just as we see up Challenger's arse when she pitches over, and can see the light from the ignition chamber.
Now, for me, I have some quick questions;
- Just looking through your Apollo 16 extract to start with, why are there frames missing? I've counted at least 9, might have been 12, fames that you don't have but I do, split in various locations across two to three seconds of footage.
- Where is your margin of error analysis? The footage is very pixelated when you try and nominate a point to measure from, either as a reference point or for determining the actual distance covered. Looking at frames I have pulled, this can be as much as ±3 pixels, and given (for me) the LM rises 55 to 56 pixels in 29 and 30 frames, this can be an error of almost 10% in the distance travelled. How have you accounted for this?
(For reference, I downloaded the Apollo 16 video you linked to and pulled 145 frames from about the 12s mark (just before we see evidence of the ignition being initiated ie the shift in the mylar of the descent stage)
