Anyone familiar with this 'claim' at Aulis.com?

[ka9q]

Here we go, from page 15-1/2 of the Saturn Flight Evaluation Report for Apollo 11.

The Q-ball angle-of-attack sensor abort limit is set to a (differential, I assume) dynamic pressure limit of 2.2 N/cm² (22 kPa, 3.2 psi). The maximum recorded pressure was 0.28 N/cm² (2.8 kPa) between T+89 and 91 sec. The total (i.e., along the longitudinal axis) dynamic pressure at max-Q (T+83 s) was 3.5 N/cm² (35 kPa).

At launch the EDS roll rate abort limit is 20 deg/s and the pitch and yaw rate limits are both 4 deg/s. At 134.8 sec (right before inboard cutoff and well after max-Q at T+83 sec) the automatic roll rate abort was inhibited and the pitch and yaw limits increased to 9.2 deg/s.

Page 11-2 gives the angle of attack around max-Q as 1.6 deg in pitch and 1.4 deg in yaw. From the discussion of high altitude winds, I presume that much of this is due to those winds and is not intentional.

[ka9q]

That eflux is VERY bright, so it's difficult to conceive of it casting any shadow, especially not one that is not easily distinguishable from the shadow cast by the rocket

Why not? Even the temperatures inside the combustion chamber don't come anywhere near the temperature of the sun's photosphere, and the plume is much cooler than the combustion chamber. And the S-IC plume is clearly opaque, at least at lower altitudes.

[ka9q]

Flight path angle is the angle the velocity vector makes with the local horizon.  Since the earth-fixed velocity vector is straight up, the earth-fixed flight path angle is 90 degrees.  On the other hand, the space-fixed flight path angle is ATAN(20/409) = 2.80 degrees.

The space-fixed flight path angle is also affected by the time since launch (because the earth rotates, changing the local direction of "up") and the distance flown downrange (because the earth curves away, also changing the direction of "up".)

The space-fixed and earth-fixed Z axes coincide at the launch site at T-17 sec, the time of guidance release.

Added: Scratch that. The Apollo convention for the launch coordinate system has, at the launch pad at the instant of guidance release, the +X axis straight up, the +Z axis downrange, and the +Y axis completing a right-handed set (i.e., pointing roughly south).

The Saturn's body coordinates coincided with these axes at this time but the CSM's coordinate system is rotated 180 deg so that X is up, -Z is downrange and +Y points roughly north. Boy, this stuff can trip you up.

[smartcooky]

They appear to have a perception that rockets accelerate and travel directly along the thrust axis, but this is only true if the rocket remains vertical. Of course, as soon as the rocket "pitches over" it begins to side-slip, as the force of gravity no longer acts along the longitudinal axis, but at some angle to it.

I don't think that's true. During this phase of flight the aerodynamic forces are almost at their peak (max-Q) so the angle of attack must be kept virtually at zero. This is done by flying a "gravity turn" wherein the rocket is pitched down just a little shortly after liftoff (when air speed and pressure are still low) and then letting gravity do the work of curving over the trajectory. Then the engines only have to follow the rocket's path, so to speak, by keeping the angle of attack near zero.

Angle of attack is one of the things monitored by the Q-ball at the tip of the launch escape rocket (angular rates are another). If it exceeds a set maximum, the Emergency Detection System automatically aborts.

I don't remember the figures offhand but I can look them up in one of the Saturn flight manuals.

Here we go, from page 15-1/2 of the Saturn Flight Evaluation Report for Apollo 11.

The Q-ball angle-of-attack sensor abort limit is set to a (differential, I assume) dynamic pressure limit of 2.2 N/cm² (22 kPa, 3.2 psi). The maximum recorded pressure was 0.28 N/cm² (2.8 kPa) between T+89 and 91 sec. The total (i.e., along the longitudinal axis) dynamic pressure at max-Q (T+83 s) was 3.5 N/cm² (35 kPa).

At launch the EDS roll rate abort limit is 20 deg/s and the pitch and yaw rate limits are both 4 deg/s. At 134.8 sec (right before inboard cutoff and well after max-Q at T+83 sec) the automatic roll rate abort was inhibited and the pitch and yaw limits increased to 9.2 deg/s.

Page 11-2 gives the angle of attack around max-Q as 1.6 deg in pitch and 1.4 deg in yaw. From the discussion of high altitude winds, I presume that much of this is due to those winds and is not intentional.

According to the Apollo 11 journals, at 00:00:34 the roll program ended and the pitch program began. Not sure how high or fast at this point; I am guessing around 1½ miles high and maybe 900 fps

By 00:01:06 the stack was 3.4 miles high and 1 mile downrange which makes the ascent vector at that point around 16.4° so that would mean that the stack is tipped over by at least 14.8° if your 1.6° max AoA is correct.

I find it hard to imagine the whole stack not sideslipping at around 650 fps at that point. It surely could not be ascending directly along the thrust vector.

Even if it were half that angle, say 7.5°, I still struggle to visualise the stack not sideslipping by a significant amount 

[Echnaton]

That eflux is VERY bright, so it's difficult to conceive of it casting any shadow, especially not one that is not easily distinguishable from the shadow cast by the rocket

Why not? Even the temperatures inside the combustion chamber don't come anywhere near the temperature of the sun's photosphere, and the plume is much cooler than the combustion chamber. And the S-IC plume is clearly opaque, at least at lower altitudes.

I am curious about the plume casting a shadow too.  Using the American terminology, the first stage was burning RP1 which is was essentially kerosene, would the combustion products be all that different from those of a paraffin wax candle?  The typical paraffin candle flame does not cast a shadow.  At some altitude the exhaust stream turns white and appears opaque, but early in the launch it would not surprise me if a good portion of the plume did not cast a shadow.   

[gwiz]

At some altitude the exhaust stream turns white and appears opaque, but early in the launch it would not surprise me if a good portion of the plume did not cast a shadow.   

Well, in the current discussion we are talking about what happens at altitude, where the extended exhaust becomes much less bright:
http://cdn.ttgtmedia.com/rms/computerweekly/photogalleries/236862/1294_20_the-apollo-11-saturn-v-space-veh~t-apollo-11-pictures-that-amazed-us.jpg

[cjameshuff]

I am curious about the plume casting a shadow too.  Using the American terminology, the first stage was burning RP1 which is was essentially kerosene, would the combustion products be all that different from those of a paraffin wax candle?  The typical paraffin candle flame does not cast a shadow.  At some altitude the exhaust stream turns white and appears opaque, but early in the launch it would not surprise me if a good portion of the plume did not cast a shadow.

The exhaust is the product of multiple large rocket engines rapidly burning large amounts of RP-1 with LOX, not a little candle slowly vaporizing paraffin from a wick and burning it with air. And in fact, candles do cast shadows...they are bright in the first place due to incandescent particles of carbon that will block light, but even the hot air from an electric heating element can cast shadows due to its different refractive index.

The exhaust would cast a shadow on any surface where the light from the exhaust is dimmer than sunlight, though it might not be as clear.

[Eventcone]

Why not? Even the temperatures inside the combustion chamber don't come anywhere near the temperature of the sun's photosphere, and the plume is much cooler than the combustion chamber. And the S-IC plume is clearly opaque, at least at lower altitudes.

But the plume (as a light source) is much closer to the clouds than is the sun (not conclusive, I know).

Also, does the plume appear opaque precisely because it is so bright to our eyes and cameras? Our iris does not allow us to see dimmer light sources (blue sky) through it?

I guess the question is: At the distance of the surrounding cloud layer, which would have the greater apparent brightness - the plume or the sun? And even if the sun is brighter and the plume casts a shadow, would it not be significantly less defined than the shadow cast by the rocket?

[Eventcone]

The exhaust would cast a shadow on any surface where the light from the exhaust is dimmer than sunlight, though it might not be as clear.

Agreed. This is the point I have tried to make.

[Echnaton]

And in fact, candles do cast shadows...they are bright in the first place due to incandescent particles of carbon that will block light, but even the hot air from an electric heating element can cast shadows due to its different refractive index.

I am aware of shadows due to different refraction.  I was using casting of a shadow it the context of casting on that is similar to that of a candle or the Saturn V rocket. Would not the shadow of the plume at the altitude in question be significantly lighter and less distinct than the shadow of the rocket? In this context, a spot light shining on a candle will cast a distinct shadow of the entire wick and no hard boundary shadow of the flame. 

[Count Zero]

What it comes down to is not how bright is the exhaust, but how opaque is it?  After all, assuming it is opaque, if the flame is bright enough to wash-out the shadow of the plume, it would also wipe-out the shadow of the rocket itself, and we do not see this.  Looking at photos of Saturn V launches, I sure can't see any details through the flame.

[nomuse]

Bah.  Any light cast by the rocket is inverse-cube.  The Sun is at infinity (at this scale, close enough to makes no difference).  Assuming the plume is actually opaque, there WILL be a distance at which no light it casts can possibly wipe out the shadow it casts.

And since it casts light in all directions, all that is necessary is for sunlight to be just a hair brighter -- no matter how lightened the shadow is, the background is lightened by an equal amount, and the shadow remains distinguishable.

[ChrLz]

Bah.  Any light cast by the rocket is inverse-cube.  The Sun is at infinity (at this scale, close enough to makes no difference).  Assuming the plume is actually opaque, there WILL be a distance at which no light it casts can possibly wipe out the shadow it casts.

And since it casts light in all directions, all that is necessary is for sunlight to be just a hair brighter -- no matter how lightened the shadow is, the background is lightened by an equal amount, and the shadow remains distinguishable.

Thanks nomuse - beat me to it..

WHAT NOMUSE SAID!!!

[cjameshuff]

Bah.  Any light cast by the rocket is inverse-cube.  The Sun is at infinity (at this scale, close enough to makes no difference).  Assuming the plume is actually opaque, there WILL be a distance at which no light it casts can possibly wipe out the shadow it casts.

Inverse square. But yes, the much greater distance to the sun means that the rocket's illumination falls off faster...the rocket is only brighter in a small volume.

And since it casts light in all directions, all that is necessary is for sunlight to be just a hair brighter -- no matter how lightened the shadow is, the background is lightened by an equal amount, and the shadow remains distinguishable.

Right. In truth, the shadow exists no matter what their relative brightnesses are...a shadow lit by one will still be dimmer than the surroundings lit by both. You just need something that can detect the difference in brightness.

[ejstans]

The authors of the Aulis article claim that Pollacia's film shows the true sequence of events in proper time, but all they do to establish this is confirming with Pollacia that the film has not been manipulated, and perform some simple analysis to try to support the films correct timing (using what they mistakenly believe is the S-IC separation as a time stamp.)

Since their arguments hinge critically on the playback speed being correct, one might think it prudent to establish this by finding other sources that agree with the Pollacia film, but instead they argue that NASA has manipulated their films and that Pollacia's film is unique in both being independent of NASA as well as showing the whole sequence from lift-off to cloud passage.

But it is possible to find other independent sources, such as this, also shot with an 8mm film camera:

The passage occurs much earlier, around the minute-mark, clearly not consistent with the Pollacia film.

In fact, the following CBS video (from the TV broadcast) is both independent of NASA, shows the whole sequence, as well as being guaranteed to have the correct time on account of being from a video camera and, you know, live broadcast:

It's entirely consistent with the above 8mm film, and shows that the cloud passage really is taking place right after the 1-minute mark, which naturally gives entirely different heights and speeds, compared with the times from the Pollacia film.

The eagle-eyed can spot a Prandtl–Glauert condensation cloud forming right before the passage, something that happens during trans-sonic speeds. Conferring with NASA tables confirms that the rocket is moving trans-sonically at this time.

The height also is completely consistent with the presence of a cirrus cloud.

Finally, for those interested, here is a high-definition clip of the Apollo 11 cloud passage (near the end):