New Air Speed Record?

FB

Not my cup of cake
Valued Member
I've been meaning to post this up for a while, although I'm not sure if the Space forum is the best place. Anyway, Boeing have set a "new" airspeed record with their X51 Waverider aircraft which managed a speed of Mach 5 for 200 seconds but the X-43A managed Mach 9.8 for about 10 seconds so I'm a little confused as to whether this is a record or not.




I'm sure NASA will claim this is all about finding cheaper ways to get rockets into space but the US military are apparently "very interested" as this would give them a missile just a tad faster than the current Cruise missiles they are using.

The aircraft use SCRAMJET technology which burns atmospheric oxygen rather than having to carry the oxide source like conventional rockets do. London to Sydney in 2 3/4 hours if they ever make a commercial airliner that goes as fast and more fun than a ride at Chessington world of Adventures!

If any of you fancy a souvenir the aircraft ditched into the pacific and neither Boeing nor NASA can be bothered to go and collect it
 

MajorDanby

Motorsports' answer to Eric the Eel
Contributor
I think its the record for the longest sustained flight above Mach 5 for a scram jet.

Th first scramjet I believe to not explode at some point during flight :)
 

cider_and_toast

Exulted Lord High Moderator of the Apex
Staff Member
Premium Contributor
I think they need to work on the design somewhat before they let fair paying passengers onboard. LOL

I think it's a case of events coming back to haunt NASA here because a lot of work was done from the 1960's onward into space planes and high altitude vehicles, most of which was cancelled because of the costs of going to the moon or because the time taken to develop such vehicles was seen as too great.

Believe it or not we Brits had our own go at designing something similar in the mid 80s:

http://en.wikipedia.org/wiki/HOTOL
 

Speshal

World Champion
Valued Member
I love stuff like this :D

Back of the fag packet calculations make that about 1240ish mph (at sea level, rounded down for the pedants)
 

MajorDanby

Motorsports' answer to Eric the Eel
Contributor
I think the main goal of the scramjet system is to attempt to attain exit velocity from the atmosphere in order to reach space without the use of booster rockets.

There ingenious really, have 0 moving parts, and simply work from the high levels of compression followed by ignition inside the engine. Trouble is there is no efficient means of accelerating them up to the speeds necessary for the engine to work. Short of propelling them with a missile that is ;)
 

cider_and_toast

Exulted Lord High Moderator of the Apex
Staff Member
Premium Contributor
MajorDanby said:
I think the main goal of the scramjet system is to attempt to attain exit velocity from the atmosphere in order to reach space without the use of booster rockets.

True and also don't forget that by burning oxygen from the air you greatly reduce the amount of fuel that the craft has to carry during flight. Take the space shuttle for example, it takes one 756 tonne external tank and two 571 tonne solid rocket boosters to lift the 110 tonne shuttle into orbit. That means that after 8 minutes the Shuttle has lost roughly 94% of its lift off weight.
 

Speshal

World Champion
Valued Member
cider_and_toast said:
That means that after 8 minutes the Shuttle has lost roughly 94% of its lift off weight.

This usually happens 8 minutes after I wake up.
 

McZiderRed

Champion Elect
Supporter
Brogan said:
This is worthy of it's own thread but once this scramjet is coupled with this laser http://www.bbc.co.uk/news/technology-10682693 it's next stop Battlestar Galactica/Star Wars/Star Trek/Babylon 5/Stargate* :D



* Choose your favourite

The trouble with this laser, is that it has no colour! It's invisible! Now, for it to be a really cool idea, it has to be a red coloured beam and make a cool noise. This laser does neither. They really haven't thought this through, have they! :no: LOL
 

cosicave

Banned
Speshal said:
I love stuff like this :D

Back of the fag packet calculations make that about 1240ish mph (at sea level, rounded down for the pedants)
In that case, I suggest your fag packet may have been left in the pocket of your jeans and shrunk in the wash!
- You might love to know that your calculations are a long way out, since 1240 is less than Mach 2.

Mach 5 = 3 806.03525 mph
Yep, more than 3800 mph…

Whilst Mach 9 = 6 850.86346 mph
6850 mph!

Low Earth orbit requires a speed of Mach 25.4 (= 19 334.6591 mph)

The term 'Hypersonic' refers to speeds in excess of Mach 5
http://en.wikipedia.org/wiki/Mach_numbe ... ach_Number
 

FB

Not my cup of cake
Valued Member
Suitably intrigued by the discrepancy between Spehsal's calculation and Cosicave's reply I had a little trawl though the net and came across this Calculator

If you bung in the indicated air speed of 3302 knots at and altitude of 50,000 ft and an air temperature of -100F (this being the nominal air temperature at this altitude) you come out with a true air speed 2082 km/h or 1293.7 mph. What I don't know, of course, is if NASA/Boeing are claiming Mach 5 as the indicated air speed or true air speed i.e. at sea level. If Mach 5 is the true air speed then this thing really was moving!
 

FB

Not my cup of cake
Valued Member
Just thinking about relative air speed, this means that if the Bloodhound does break through the 1,000 mph barrier it won't, in relative terms at least, be that much slower than this Boeing aircraft. If you think of the sizes of the budgets of these two projects it makes you realise just how incredible the Bloodhound achievement would be should they reach their goal.

Also, for no reason other than it is a fantastic photograph, this is what breaking the sound barrier looks like.

 
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