March 9

8:30 March 8. Don't know and don't care how they chose the date as international women's day what bothers me is the shape of the later 8 chosen as symbol.

Was thinking about writing about scramjet engines and hypersonic rockets when a big noise started outside. A city sewage cistern started a terrible noise outside. Though it can't be recorded due to low frequencies, it vibrates the building and in first stage or first 10 minutes noise outside should have been over 100 dB. Right now it's at 50 or something.

8:53 Noise is gone, all that's left is the dust that i breath but sill i want to continue. Here is the diagram of a scramjet engine around which is built the hype with the hypersonic rockets whatever (technically they are not rockets since they use jet, not rocket engines and lift to stay in the air).

Though in reality air does not hit the engine at full speed of the "rocket", because the inlet is not in the tip of the rocket but under, due to fact that the tip exposed to those speeds is glowing red hot. (Could at those speeds asymmetrical diversion inwards of air flowing create a rotating momentum that could throw the rocket off course)

Anyways here's the discussion.

Scramjet unlike turbojets or turbofans on commercial aircrafts to not have moving parts (fans, turbines). Thus they cannot start unless they (inlet air) reaches a speed of about Mach 4 to 4.5 which must be achieved by different means, that could be solid fuel rockets when air entering the inlet (here the sewage cistern started again 9:01). Top speed of a Mig 31 is about Mach 2.8.

As the diagram suggests, the speed and the pressure of the air is increased as entering the engine. We don't have the data so we don't how how much but we know those fly in the atmosphere at hypersonic speeds (where scram engines can work), or heights where air density is less than 1% of that at sea level. Pressurized air is then injected with a fuel, that can by hydrogen cause it has the highest energy per mass ratio of all fuels which is stored liquid at high pressure in a fuel tank (it is my understanding that it first goes in the tip of the rocket to cool it before being injected, otherwise the tip would melt quickly).

From now on it's a balance of pressures and speeds. Pressure in the burning chamber cannot go near pressure in the inlet cause otherwise it would cause air starving.

Questions. Would the starting speed be different at different altitudes because of differences in air density and pressure? If the starting speeds of Mach 4 or 4.5 are at the starting altitudes where a Mig 31 can fly, then what will happen with the pressure inside engine during final descent on the target were ambient air pressure increases hundreds of times? I would assume you would have to pump enough fuel to prevent extinguishing of the engine (mixture too lean) thus increase speed? Or have some sort of valve to adjust the amount of air it enters the combustion chamber.

Can't find right now with the noise (on and off) and everything the speed of exhaust in jet engines. But i would assume at least during acceleration they should obey the law of conserving momentum. m1v1=m2v2 where m1 is the plane (hyper rocket) and m2 is the mass of ejected fuel, v1 is the delta speed of the "rocket".

You have a speed difference of mach 0.5 or 1 or two or from 4.5 to 5 or 6 with an exhaust speed unknown that cannot be much higher than in turbo jet engines due to pressure limitations of the thickness of walls of the exhaust nozzle which cannot be much thicker thani in a turbojet but especially because of the inlet stagnation pressure.

In a way a scramjet is an afterburner without an engine, but in a turbojet afterburner the pressure coming from the turbojet is much greater than the pressure of air passively "rammed" in the scramjet by the speed of the air alone.

If there was no drag, the "rocket" should fly only by inertia but the engine is then needed only to beat the drag. In other words to supply the energy for the tip of the rocket to get red hot.

I would assume that if you can accelerate the rocket from Mach 4 or 4.5 (the initial starting speed of the scramjet) to 5 with your scramjet then you can call it hypersonic. (Can't see the engine in this generic diagram but the fuel tank seems awfully small). Based on assumption that efficiency of the scramjet being similar to a turbojet (fuel per distance) on afterburner and extrapolating the amount needed when flying at Mach 5 we imagine that the "rocket" would need more fuel for flying more than a hundred km or so.

10:08 Second challenge of the day. The thundering garbage truck.

1:10 Went for a walk, have stories to tell, don't have the time. Perceived air quality was 50, my mind wouldn't clear (there was a new hole next to the middle of the lawn). And i've been subjected to a bizarre allegory with several big vehicles in the middle of the road and working at the sewers. Could have something to do with back pressure, i read the word BAK on one of their devices inside a vehicle with open doors.

What we can note in the diagram above is the presence of a high pressure nitrogen tank. Nitrogen does not burn but simply increases the pressure in the tiny hydrogen tank so it can make it to the burning chamber. I would assume there is a separation membrane in the hydrogen tank so they won't mix.

From here we can get a clue on the pressure in the burning chamber. So the walls of the engine should be as thick as the nitrogen tank walls which means heavy.

And a question. Why not simply use a rocket engine and carry oxygen instead of the inert nitrogen in a similar tank. The rocket engine would not have any of the severe limitations of a scramjet. BTW i can't see any air intake in the picture of the rocket under Mig's belly.

I think they maintain the scramjet vs rocket engine myth because it theoretically uses air from atmosphere so they can carry more fuel, as a rocket of this size needing to carry both oxygen and hydrogen tanks wouldn't make it very far.

2:22 Ok i know who the guys in the street were. Sciento. Because i wrote of them last night. One of them, the first guy with the first vehicle was Tom Cruise. Even with the big moustache, his face doesn't look so fresh anymore. When i was nearest, he gave me a strange look, like staring at me for a few seconds as i passed. The other was a mime actor.

Their vehicles were in the middle of the road, up and down hill, with traffic diverted partly on bike lanes and were maneuvering some thin hoses (5/8 maybe), one going into each sewer hole.

The second guy, the mime, was at the vehicle downhill and was maneuvering energetically some hoses that were attached to some devices).

When i came home at a certain point i went with a spray extender and poured something in the mole holes in the middle area between buildings, similar to what they were doing. At the second hole, or uphill, there was a noise behind me making me very nervous, i made a move, the extension came out of the nozzle, sprang up and i got one or two drops of that in my right eye. Within a couple of minutes i was in the shower rinsing my eye. Now i got moderate pain and redness in that eye but so far i don't think it's serious.

This is an example of mind programming, what they call engrams, a combination of mind altering drugs, distraction and inducing into suggestibility all known to classical psychology. They probably use it to impress novices and make a link with Hubbard's writings. Needless to say, the whole area was subjected to the same smoke.