Reaction Engines Passes the 3.3 Mach test

Hi Guys and Girls,

This is interesting:

aviationweek.com... rid=CPEN1000001733144&utm_campaign=19190&utm_medium=email&elq2=e1966abd25554ce8a0d0a976310a0ede

With the test item passing the test and the hopes to test at Mach 4+, add to the mix interest and investment from the MOD, RR and BAE systems this is about to get interesting.

I WISH that Reaction engines were a listed company (I'd be buying more than I did on Yellow Cake) and I hope this isn't a repeat of the RB545 that disappeared into a black hole or maybe the black world never to be seen again.

RAB

This is one company I have been keeping a close eye on. Interestingly, the uses for the Sabre engine could be the starter of many things, including spaceplanes and quick travel. See the concepts for Skylon.

I hope that the new UK spaceports will see a Bristish built spaceplane.

a reply to: paraphi

This is just the precooler tests. They have not tackled the rest of the engine. Mach 3.3 is a long way from mach 25 (orbital velocity). Their mass fractions for an orbital vehicle dont add up. In rocketry, mass fraction is everything and the tolerances are very, very tight.

Tbh, as cool as this is, we are looking at a minimum of ten, if not 30 years for a sabre based orbital vehicle.

a reply to: anzha

This escape velocity has me a bit confused.

Is it not correct that this is the speed at which an object will not require any additional force to escape the gravitational pull of a planet?

You don't need to travel fast to escape the earth as long as you have a continual thrust to counter gravity, drag and other forces?

They float balloons to the very edge of space and not very fast.

If you, or anyone else, can enlighten me I'd be very interested to learn.

a reply to: beetee

Belongs on another forum, but wth.

Orbit is not just a place. Orbit is a vector: both a speed and a location. It means the lateral speed of an object is balanced with the pull of gravity so it produces a circular path around the object.

A balloon up at 100 km is not in orbit: the force balancing gravity is the lift of the balloon, not speed.

If you go faster than the balancing act of speed and gravity, then that is what they term escape velocity. This means the speed and direction you are going is enough to allow you to get away from that object, both to not be brought back down to the object or to be in orbit around it. Hence, the name 'escape.' There is Earth escape velocity, but that is different than for Mars. Or Jupiter. Or the Sun.

a reply to: anzha

Ok, thanks.

But, since SSTO was the point of Skylon, my point is that to escape the earths gravitational pull all you have to do is to consistently provide a force greater than the gravitational pull of the earth.

Speed is, if I understand it correctly, irrelevant unless you want to cut off thrust.

I understand this is tangential to the subject matter in an aircraft forum, but since the USAF is talking about LEO tankers I guess it can be weakly defended.

a reply to: beetee

SSTO is a great idea on paper, but not really useful for much more than maybe transporting small loads quickly from Point A to Point B. You need so much fuel to get to orbit that you can't carry a large, useful payload, unless it's a big beast, which needs more fuel, and on and on.

a reply to: Zaphod58

Thanks. But if you could provide sustained thrust/force and come up with a power source that could produce a lot of power for a reasonble amount of weight, then you could do it. And you don't have to do it fast, necessarily.

The main problem, as I understand it, is that the current weight to thrust ratio of rocket fuels are a severely limiting factor.

My chemistry and physics classes are far in my past, and I am not an engineer, so forgive me if I speak heresy :-)

I hope this isn't too far off topic.

a reply to: beetee

Skylon isn't designed to escape earth velocity. It's intended to reach orbital velocity. Not the same thing.

Escape velocity is intended only if you want to go to elsewhere in the solar system or even leave the solar system. You don't need escape velocity to go to the Moon, for example. The changes in velocity to /land/ are greater. Or to go into orbit around the moon. Skylon is not intended for those either.

Due to the low level of air resistance beyond the Kaman line, you can turn off your engines once you have enough speed and you will stay in orbit a long, long time. There's still air up there, just very, very thin, so anything below medium earth orbit will eventually decay its orbit and fall back to earth.

It should also be noted, escape velocity means you are going away from the earth.

Look up the rocket equation. Rocket scientists live and die by it.

a reply to: Zaphod58

SSTO only makes sense if you are going to fly to and from orbit ALOT and it doesn't cost much to refurbish the spacecraft.

Otherwise, TSTO (like what SpaceX is doing and Blue Origin will do) makes more sense.

a reply to: anzha

Ok, thanks. I will have to read up.

I don't think rockets will be the future, though, that's why Skylon fascinated me when I first came across it :-)

EDIT:

Just a look at what some others are thinking about doing. The potential future competition, so to speak..

New Scientist Plasma Jet Engine Article from 2017

a reply to: beetee

Correct.
You could climb to space on a big enough ladder*

(* as well as several other obvious things!)

a reply to: ziplock9000

Space elevators are a theoretical thing.

For the Moon and Mars, we have materials that could work, but it would require launching the equivalent of a Falcon Heavy every day for something like 5 years to get enough material for the moon elevator.

For Earth, it appears we don't know of any materials that would work. Molecular bond issues. Even carbon nanotubes failed badly, turning out to be far, far weaker than what they could be in theory when tested. NASA ran a competition for developing the materials for an elevator called the 'strong tether' competition. They cancelled it because there was little to no progress after several years.

And all of this belongs on the space exploration board.

a reply to: beetee

to escape the earths gravitational pull all you have to do is to consistently provide a force greater than the gravitational pull of the earth. 

Speed is, if I understand it correctly, irrelevant unless you want to cut off thrust. 

You should un-understand that all because it doesn't at all reflect what is going on in space.