Humor Random Comments Thread

[Pipcard]

Can't wait for the Lunar Olympics! 1/6 gravity will make sports a lot more interesting.

 

[Athena]

our cars are always oxidizing; we just try to keep it from happening suddenly.

I love xkcd. :lol:

 

[rseferino]

Does anyone know how to make a good Orbiter video? Fraps just isn't working right on my computer...

Making a good video ... I record almost an hour to get a few minutes of finished material :compbash:

That problem to have FRAPS? Which version you have?

 

[Urwumpe]

Funnily, the current storm in Germany got the name "Elon" and is much stronger than expected. Is that an omen for the launch tomorrow?

 

[Quick_Nick]

 

[ex-orbinaut]

A6 ugly? From which side it's ugly?

There was one that took pride in the fact...

"Ugly, but well hung"

Though it is nowhere near as ugly as its more effective successor. Now that is one ugly aircraft, unless of course beauty really is in the eye of the beholder...

 

[fsci123]

I thought I would never see the day when gas prices rehit $1.99...

Also does anyone know any scientific papers about the cost of launching cargo into Leo/TLi/TMI and how such cost will be effected by the addition of reusable launch vehicles, SSTO, or propellant depots.

 

[Fabri91]

Hybrid rocket engines are marvellously "simple" mechanically but a to even (very) roughly size :beathead:

 

[fsci123]

Hybrid rocket engines are marvellously "simple" mechanically but a to even (very) roughly size :beathead:

Don't they have problems like spontaneous explosions?

 

[Fabri91]

Well, funny transients can have many causes, but yes, they appear to be a bit of a concern in hybrids during throttling operations.

What I'm more referring to is that hybrids, as opposed to liquid rocket engines or SRMs, don't really operate in a steady condition, as in a constant oxy/fuel ratio, which complicates many things to say the least, since chamber pressure and combustion products are constantly changing so that one doesn't really have a set of steady "design conditions".

 

[N_Molson]

I wonder how much petroleum prices can affect the LOX/RP-1 rocket launches prices, if it does ?

That engine only needs oxygen and hydrogen anyways. Pure beauty :

:camera:

So the outer skin of the nozzle stays cold enough for water vapor to condensate immediately into ice ? Impressive.

 

[Fabri91]

Well, it is regeneratively cooled, i.e. hydrogen is run through small tubes along the nozzle wall to cool it

 

[N_Molson]

Well, it is regeneratively cooled, i.e. hydrogen is run through small tubes along the nozzle wall to cool it

Sure, but still, the temperature inside is like 6,000°C :blink:

So in theory, if you can approach the nozzle enough and put a hand on it, it stays sticked to it and the cold probably freezes all your blood in a matter of seconds ; if you move it a few centimeters inwards, it is immediately incinerated. Space environnement is friendly compared to that. :lol:

 

[Fabri91]

I'm sure that while the outside wall of the nozzle is really cold, the inside one is quite a bit more...toasty.

 

[ISProgram]

You're not calling the A-10 ugly, right..? :huh:

 

[Urwumpe]

I'm sure that while the outside wall of the nozzle is really cold, the inside one is quite a bit more...toasty.

The inside wall is also not at the 6000°C that you have in the center of the combustion chamber. There is a bit of film cooling taking place by injecting hydrogen-rich gas at the sides of the combustion chamber without also injecting oxygen into the stream, also the exhaust cools a bit while expanding in the noozle.

I have some simulation data here, it is not 100% accurate, but gives you a good impression of the conditions at the nozzle heat exchanger:

Variable | Description | Units | 65% RPL | 100% RPL | 104% RPL | 109% RPL
t_4|Fuel temp. inside nozzle HE|R|449.5|465.8|456.4|448.1
t_5|Fuel temp. inside MCC HE|R|509.0|466.0|455.9|443.1
t_9|Preburners fuel supply line temp.|R|295.4|276.4|276.4|276.5
t_op|Oxidizer preburner temperature|R|1,057.0|1,440.3|1,475.8|1,517.6
t_fp|Fuel preburner temperature|R|1,633.5|1,753.9|1,796.1|1,854.8
t_fi|Fuel injector temperature|R|1,392.7|1,560.7|1,593.1|1,636.2
t_c|Main chamber (MCC) temperature|R|6,400.0|6,400.0|6,400.0|6,400.0
tw_15|Hot wall temp. at MCC HE|R|1,228.8|1,214.9|1,203.1|1,187.1
tw_25|Cold wall temp. at MCC HE|R|509.0|466.0|455.9|443.1
tw_14|Hot wall temp. at nozzle HE|R|1,162.5|1,260.3|1,250.4|1,244.5
tw_24|Cold wall temp. at nozzle HE|R|449.5|465.8|456.4|448.1

In case Rankin aren't that easily understood... I can also convert the data into K or °C, the original table was calculated in Rankin

 

[C3PO]

You're not calling the A-10 ugly, right..? :huh:

Not to its face anyway.

 

[Fabri91]

The inside wall is also not at the 6000°C that you have in the center of the combustion chamber. There is a bit of film cooling taking place by injecting hydrogen-rich gas at the sides of the combustion chamber without also injecting oxygen into the stream, also the exhaust cools a bit while expanding in the noozle.

I have some simulation data here, it is not 100% accurate, but gives you a good impression of the conditions at the nozzle heat exchanger:

table

In case Rankin aren't that easily understood... I can also convert the data into K or °C, the original table was calculated in Rankin

Nice, thank you!:tiphat: Rankine is fine, it's not as unfamiliar a unit as a hogshead or a buttload

 

[ISProgram]

Hey guys, how big can an add-on documentation be? Working on one, and I kinda wanted to, um, overdo it a bit...

Also, why do people think the A-10 is ugly?

 

[Andy44]

A-10s are not pretty, but they are not Navy-ugly like the A-6. I think the A-10 is very well-proportioned and looks great for a plane that is designed to be basically a flying tank.

I think the only reason the USAF agreed to fly it was to make sure the US Army didn't talk Congress into letting them have some fixed-wing jets again...the operation of fixed wing planes is jealously guarded by the Air Force, who to this day have still not gotten over the divorce with the Army in the 1940s. They lobbied Congress into allowing the Army to have only rotor wing aircraft, aside from a few spotter planes and VIP jets.

Fortunately the Navy and Marines play nicer together when it comes to aviation, and it works out even better since Marine aircraft are all part of the Navy's maintenance and supply system and many of the parts and technical skills are interchangable. All Marine pilots are actually Navy-trained and Marine Corps air units frequently "plug into" Navy units and act as part of the carrier air wing when needed.