Bloodhound SSC: How do you build a car capable of 1,000mph?

Rockets and jets power a land speed record attempt and STEM outreach project.

Read the whole story

 

[nivnac]

Before each run, volunteers have to walk the entire length of the course and remove any loose rocks or stones to prevent them being sucked into an engine or otherwise damaging Bloodhound SSC. Given the length involved, this is no small task,

This is slightly misleading, while I'm sure a final check of the course will be undertaken before each run, preperation has been going on for years! See this article from 2012 when the bulk of the work was done.

Ars readers may also be intersted that they have built four comm masts on the plain so that the car can have multiple 3.5Mb streams sending live HD video and data during runs. It is going to be amazing watching live.

 

[ExMancunium]

According to the article: ....the car's auxiliary power supply will need at least 750bhp to drive the HTP pump.

Can someone explain why the auxiliary power supply needs to be so powerful? I'm guessing it's to do with how much HTP you can shove through the rocket engine, thus impacting total thrust produced. And I play KSP, so I'm pretty qualified to comment on this!

"What a total waste of money and talent. Human stupidity knows no limits, even with the smartest people."

This, and the various other comments like it, gave me a good laugh. Nobody knew what the benefits to science of the Moon landings would be, but they still did it, to the net benefit of science and technology. That's a good enough reason to start with.

But then you have to picture this scenario between a couple of guys and a girl they both meet at a party:

Guy 1: "I drove a jet- and rocket-powered car at over 1000mph. Twice. I'm also a fighter pilot"

Girl: "That's pretty cool. Science is fun!"

Guy 2: "That's nothing, I'm Dave from the Internet, perhaps you've heard of me?"

Girl: *awkward silence*

I hate the fact that money and responsibilities make me Guy 2 in this scenario, and would love to be Guy 1

(Notes:
1 - Whoever's quote that is, yours was the best version of a sentiment a lot of people expressed, I'm not aiming this entirely at you
2 - Feel free to substitute girls for guys and vice versa, my main point is that being 'from the Internet' is not as impressive as a chat-up line as being a fighter and rocket car pilot
3 - My name is not Dave)

 

[raxx7]

ExMancunium[/url]":3f07qmvr]According to the article: ....the car's auxiliary power supply will need at least 750bhp to drive the HTP pump.

Can someone explain why the auxiliary power supply needs to be so powerful? I'm guessing it's to do with how much HTP you can shove through the rocket engine, thus impacting total thrust produced. And I play KSP, so I'm pretty qualified to comment on this!

It needs to be able to pump 1000L of HPT in 17 seconds, at a pressure than can overcome the pressure of the combustion chamber.

 

[legacyABQ]

I would definitely be interested in learning more about this vehicle's wheel-design

 

[phred14]

raxx7[/url]":21tuh533]

ExMancunium[/url]":21tuh533]According to the article: ....the car's auxiliary power supply will need at least 750bhp to drive the HTP pump.

Can someone explain why the auxiliary power supply needs to be so powerful? I'm guessing it's to do with how much HTP you can shove through the rocket engine, thus impacting total thrust produced. And I play KSP, so I'm pretty qualified to comment on this!

It needs to be able to pump 1000L of HPT in 17 seconds, at a pressure than can overcome the pressure of the combustion chamber.

IIRC, the F1 engines on the Saturn V required 2-stage turbopumps to drive the main engine. The first-stage turbopump pumped propellents for the second-stage turbopump, which pumped propellents for the main engine. There have been recent efforts to resurrect the F1, including grabbing museum pieces for reverse-engineering. FWIU, so far they've fired the second-stage turbopumps, though I doubt they were actually pumping anything. As a point of interest, they've been using extensive 3D printing in this resurrection effort. The original parts were marvels of hand-worked metal, and 3D printing is proving very effective in those situations as a cost-containment method.

 

[ArchimaX]

Hydrogen Peroxide for the win!

H2O2 powered cart (it pops at the end)

http://m.youtube.com/watch?v=b6PLGayRTBM

 

[kdavis]

People shouldn't try to go 1000 mph on land. That speed is suitable for the air, and if you can fly affordably at that speed you'll make a fortune on commercial flights. To do it on the land is simply dangerous.

 

[ShakuArai]

kdavis[/url]":2qz26b3w]People shouldn't try to go 1000 mph on land. That speed is suitable for the air, and if you can fly affordably at that speed you'll make a fortune on commercial flights. To do it on the land is simply dangerous.

They are aware of the danger involved yet they still want to try it, might as well collect all the data and make it count towards something more productive. You are right though, going anywhere near 1,000mph is not suitable for land. (It is probably the very reason they want to try it, to prove it can be done.)

 

[ChaoticUnreal]

ShakuArai[/url]":32y42vpn]

kdavis[/url]":32y42vpn]People shouldn't try to go 1000 mph on land. That speed is suitable for the air, and if you can fly affordably at that speed you'll make a fortune on commercial flights. To do it on the land is simply dangerous.

They are aware of the danger involved yet they still want to try it, might as well collect all the data and make it count towards something more productive. You are right though, going anywhere near 1,000mph is not suitable for land. (It is probably the very reason they want to try it, to prove it can be done.)

You are aware they are going to do this on a controlled track right. Not some random street. There is nothing more dangerous about going 1000 Mph on a controlled track on land than there is doing it in the air.

Also I thought one of the reasons the concord was retired was that people didn't like going supersonic and governments didn't like planes going supersonic near population centers due to the sonic boom.

 

[Dr Gitlin]

kdavis[/url]":1fsdp2dj]People shouldn't try to go 1000 mph on land. That speed is suitable for the air, and if you can fly affordably at that speed you'll make a fortune on commercial flights. To do it on the land is simply dangerous.

Before Yeager's first Mach 1 X-1 flight people thought it was too dangerous to break the sound barrier and that any plane that tried would destroy itself in the process.

 

[ShakuArai]

Deus Casus[/url]":2308lhxg]

ShakuArai[/url]":2308lhxg]

kdavis[/url]":2308lhxg]People shouldn't try to go 1000 mph on land. That speed is suitable for the air, and if you can fly affordably at that speed you'll make a fortune on commercial flights. To do it on the land is simply dangerous.

They are aware of the danger involved yet they still want to try it, might as well collect all the data and make it count towards something more productive. You are right though, going anywhere near 1,000mph is not suitable for land. (It is probably the very reason they want to try it, to prove it can be done.)

You are aware they are going to do this on a controlled track right. Not some random street. There is nothing more dangerous about going 1000 Mph on a controlled track on land than there is doing it in the air.

Also I thought one of the reasons the concord was retired was that people didn't like going supersonic and governments didn't like planes going supersonic near population centers due to the sonic boom.

Perhaps I overstate the dangers involved but not by much, what you call a controlled track does not eliminate the risk of something going wrong. Also one of the main reasons of the Concorde was retired from service was the escalating cost of operation and the accompanying price raises consumers had to deal with.

 

[Alhazred]

Dr Gitlin[/url]":2uyycbs5]

kdavis[/url]":2uyycbs5]People shouldn't try to go 1000 mph on land. That speed is suitable for the air, and if you can fly affordably at that speed you'll make a fortune on commercial flights. To do it on the land is simply dangerous.

Before Yeager's first Mach 1 X-1 flight people thought it was too dangerous to break the sound barrier and that any plane that tried would destroy itself in the process.

Aerospace engineers didn't believe it was impossible. 'Too dangerous' is a subjective thing. It was quite well known to be POSSIBLE, and it certainly WAS dangerous. The difference here is there's no clearly defined justification for doing it. The X-1 program was clearly necessary to advance flight and the very fact that supersonic flight is routine today proves it was a needed advance. Nobody needs to go 1000 MPH on the ground. So obviously the criteria are a bit different.

 

[pchase]

The power vs speed math at the beginning of the article is wrong - Power is closer to speed cubed than speed squared for the regime we're talking about here.

Power is simply force times velocity (speed). For an object moving through air at high speed drag can be modeled by the Rayleigh equation, which is proportional to speed squared. Substituting yields:

Power = force * velocity
Force = 0.5*Cp*A*velocity^2

Power = 0.5*Cp*A*velocity^3

The big catch is that at Bloodhound SSC's supersonic speeds there is also wave/compressibility drag to contend with, but it doesn't change the bottom line all that much.

 

[provocateur52]

Whatever engine. All I remember from my misspent childhood is Breedlove's rocket car. Fastest=best. Motorcycle land speeds? Another issue altogether and IMO will ultimately benefit "need for speed" technology.

 

[afidel]

Very cool, after watching the static test I wondered at the exhaust portion of the engine, thinking thrust vectoring didn't seem right for a vehicle that's going to move in 2 dimensions so I got to learn about variable area geometry in exhaust nozzles of turbofan engines (basically at lower thrust you need to supply less backpressure to keep components within design tolerance).

I'm surprised that they are going with Nammo for the hybrid rockets, SpaceX now knows more about operating hybrid rockets than anyone since the Merlin family has more time than probably all other companies combined. I guess it's due to the UK ministry financing, they probably are encouraged to use domestic sources.

 

[raxx7]

Nammo isn't british, it's norwegian.
It seems they (think) Nammo can deliver the rocket faster.
Aparently, Nammo (which manufactures rocket for a number of missiles) has been researching hybrids as well for a while.
If I had to guess, I'd say that in terms of rocket size, Nammo's interests are more closely aligned with Bloodhound than SpaceX.

 

[Nabu the Wise]

Thats very cool. Now make one with an oscillation overthruster!

 

[Geppeto35]

just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

 

[althaz]

Geppeto35[/url]":12f91t0e]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

Whilst I agree in principle, I actually disagree in this specific instance. Yes, the land-speed record is not actually measured officially in MPH, but it's a familiar enough term for a lot of people. The other common term is km/h which is also not the standard unit for speed/velocity (m/s is the SI unit). So whilst using SI terms should be almost always used, when talking about cars I think MPH is actually fine for a US website (most US people won't really understand km/h). That said, I think for the international audience (I have no clue, but I'd guess maybe half the readers?) including figures for the common method of measuring speed most other places (km/h) would benefit the article by being placed in brackets next to the MPH speeds.

It's also worth noting that the US is not the only country to use MPH.

 

[Dr Gitlin]

Geppeto35[/url]":1izg202s]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

OK, how's this? They plan to do 14107203728640 mm/year.

 

[Aurich]

I always wonder what people would think of Americans showing up on other country's web sites demanding that everything be measured in inches. I suspect you'd find us rather boorish. Somehow the opposite doesn't remain true in your minds. Just in case you were wondering, we don't find it charming.

Ars is based in the United States. Obviously we have a large international audience, but you are reading a "foreign" site. That's going to come with certain idiosyncrasies, like having to put up with our units of measure, or not having extraneous u's in words like "color".

 

[Dr Gitlin]

althaz[/url]":2e89hzkm]

Geppeto35[/url]":2e89hzkm]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

Whilst I agree in principle, I actually disagree in this specific instance. Yes, the land-speed record is not actually measured officially in MPH, but it's a familiar enough term for a lot of people. The other common term is km/h which is also not the standard unit for speed/velocity (m/s is the SI unit). So whilst using SI terms should be almost always used, when talking about cars I think MPH is actually fine for a US website (most US people won't really understand km/h). That said, I think for the international audience (I have no clue, but I'd guess maybe half the readers?) including figures for the common method of measuring speed most other places (km/h) would benefit the article by being placed in brackets next to the MPH speeds.

It's also worth noting that the US is not the only country to use MPH.

Right, this is a British project and speed in the UK is measured in mph.

 

[Pewmaymen]

Dr Gitlin[/url]"ssxmtnx]

Geppeto35[/url]"ssxmtnx]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

OK, how's this? They plan to do 14107203728640 mm/year.

hahaha!

 

[milliamp]

Honestly what is the difference between a 1,000 automobile and a plane that is just touching the runway? At those speeds being close to the ground is just an unnecessary liability and requires much more energy to penetrate the air due to the greater atmospheric pressure on the ground.

TL;DR After breaking the speed of sound its pretty much a plane with the landing gear down.

 

[tiggers]

I'm getting car sick just thinking about this...

 

[realwarder]

Great article. Thank you!

 

[YetAnotherAnonymousAppellation]

Dr Gitlin[/url]":3uz77z7k]

althaz[/url]":3uz77z7k]

Geppeto35[/url]":3uz77z7k]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

Whilst I agree in principle, I actually disagree in this specific instance. Yes, the land-speed record is not actually measured officially in MPH, but it's a familiar enough term for a lot of people. The other common term is km/h which is also not the standard unit for speed/velocity (m/s is the SI unit). So whilst using SI terms should be almost always used, when talking about cars I think MPH is actually fine for a US website (most US people won't really understand km/h). That said, I think for the international audience (I have no clue, but I'd guess maybe half the readers?) including figures for the common method of measuring speed most other places (km/h) would benefit the article by being placed in brackets next to the MPH speeds.

It's also worth noting that the US is not the only country to use MPH.

Right, this is a British project and speed in the UK is measured in mph.

Since when? Unless they've changed back to Imperial without my knowing it, the UK has been metric for decades now. Just like any formerly non-metric country, there is still a mix of units used by the general public (which is diminishing as the "old guard" dies off), but officially it is metric.

 

[Dr Gitlin]

YetAnotherAnonymousAppellation[/url]":1jdr73jt]

Dr Gitlin[/url]":1jdr73jt]

althaz[/url]":1jdr73jt]

Geppeto35[/url]":1jdr73jt]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

Whilst I agree in principle, I actually disagree in this specific instance. Yes, the land-speed record is not actually measured officially in MPH, but it's a familiar enough term for a lot of people. The other common term is km/h which is also not the standard unit for speed/velocity (m/s is the SI unit). So whilst using SI terms should be almost always used, when talking about cars I think MPH is actually fine for a US website (most US people won't really understand km/h). That said, I think for the international audience (I have no clue, but I'd guess maybe half the readers?) including figures for the common method of measuring speed most other places (km/h) would benefit the article by being placed in brackets next to the MPH speeds.

It's also worth noting that the US is not the only country to use MPH.

Right, this is a British project and speed in the UK is measured in mph.

Since when? Unless they've changed back to Imperial without my knowing it, the UK has been metric for decades now. Just like any formerly non-metric country, there is still a mix of units used by the general public (which is diminishing as the "old guard" dies off), but officially it is metric.

The UK has used mph for speeds and speed limits from at least 1978 when I emigrated there, continued to use mph for the 24 years that I lived there until 2002, and have continued to use mph for speed ever since.

https://en.wikipedia.org/wiki/Road_spee ... ed_Kingdom

https://www.gov.uk/speed-limits

 

[ExMancunium]

Dr Gitlin[/url]":2k80bog2]

YetAnotherAnonymousAppellation[/url]":2k80bog2]

Dr Gitlin[/url]":2k80bog2]

althaz[/url]":2k80bog2]

Geppeto35[/url]":2k80bog2]just a remark... the International System of Units uses meters and seconds... miles should make us smile: old measure, non-decimal (or based on any other numeral system).

What about deserting mph or providing us some meter metrics?

(-;

Whilst I agree in principle, I actually disagree in this specific instance. Yes, the land-speed record is not actually measured officially in MPH, but it's a familiar enough term for a lot of people. The other common term is km/h which is also not the standard unit for speed/velocity (m/s is the SI unit). So whilst using SI terms should be almost always used, when talking about cars I think MPH is actually fine for a US website (most US people won't really understand km/h). That said, I think for the international audience (I have no clue, but I'd guess maybe half the readers?) including figures for the common method of measuring speed most other places (km/h) would benefit the article by being placed in brackets next to the MPH speeds.

It's also worth noting that the US is not the only country to use MPH.

Right, this is a British project and speed in the UK is measured in mph.

Since when? Unless they've changed back to Imperial without my knowing it, the UK has been metric for decades now. Just like any formerly non-metric country, there is still a mix of units used by the general public (which is diminishing as the "old guard" dies off), but officially it is metric.

The UK has used mph for speeds and speed limits from at least 1978 when I emigrated there, continued to use mph for the 24 years that I lived there until 2002, and have continued to use mph for speed ever since.

https://en.wikipedia.org/wiki/Road_spee ... ed_Kingdom

https://www.gov.uk/speed-limits

He's spot on with this. When I was done for speeding last year it wasn't for doing 126.4 in a 112 zone :eyebrow:

 

[Tsa Szymborska]

How about a feature that makes you choose between SI unit or other units in technical articles like this one? Ars is read by many people in many countries. There are only three countries in the world that still use the imperial system. Please let us choose.

 

[Aurich]

Tsa Szymborska[/url]":1md1r1ou]How about a feature that makes you choose between SI unit or other units in technical articles like this one? Ars is read by many people in many countries. There are only three countries in the world that still use the imperial system. Please let us choose.

I wouldn't be opposed to such a thing, we could ponder how to make it work. It's not that we hate other countries and their units, it's just that Ars is a US site, and we're going to use the units that are native to us. I get it, inches are weird and confusing, base 16 wtf. But as long as it's what we use here it's what makes sense to us.

 

[Dr Gitlin]

Tsa Szymborska[/url]":31h414va]How about a feature that makes you choose between SI unit or other units in technical articles like this one? Ars is read by many people in many countries. There are only three countries in the world that still use the imperial system. Please let us choose.

Now imagine you grew up learning to write British English and now you have to spell everything without the extra Us and use Zs instead of Ss.

This browser plugin should help you: Here's a handy chrome plugin you might like, it;ll do that for you: https://chrome.google.com/webstore/deta ... apnd?hl=en

 

[lost]

Human beings achieved many 'firsts' in the 20th century.

It seems they already break all real 'firsts' in 20th century for cars - in '97 they broke speed of sound.

Any arbitrary number like 1000mph is just that ... arbitrary. Not to mention that for this team kmh should be more logical measurement unit ( and 1000kmh was already broken too).

I always admire desire to do things 'better', and any broken record is good thing. BUT we have only so many *real* 'firsts' that are defined by nature and not by our arbitrary units. Examples of non arbitrary 'firsts':
- breaking sound barrier (since speed of sound is independent of our units, mph, kmh...)
- climbing highest mountain on world ( again, regardless of how we measure height, meters, feets ... highest mountain is highest)
- going into space (since it is defined by natural boundaries, like where atmosphere stops, and not by human arbitrary height)
- ...

So I would say that they will break record, but not really break any real 'first' with this new car - like they did break 'first' for speed of sound in last car.

On a side note - what real 'firsts' remained that were not achieved in 20th century?

 

[tjoynt]

This makes me want to watch "The Adventures of Buckaroo Banzai Across the 8th Dimension" again. Also, can't wait for the next Burn! )'(

 

[tallandrew]

Great article. However, there is a misleading error regarding power.

In the "brief history of speed" section, it says:

"In plain English, a car that needs 100hp to reach 100mph would need 400hp to reach 200mph, or 900hp to reach 300mph."

Apparently, someone should learn the difference between force and power. This difference is taught
in basic physics/engineering classes (high school level).

The FORCE (!) -- otherwise known as aerodynamic drag -- increases as the square of the speed. Therefore, the FORCE increases by a factor of 9 as the speed increases by a factor of 3. But the POWER increases by a factor of 27 as the speed increases by a factor of 3. So a car that needs
100hp to reach 100mph would need 2700hp to reach 300mph.

Tall Andrew
Mechanical Engineer, physics enthusiast, and longtime fan of land speed racing

 

[Fatesrider]

danchr[/url]":8q8o8ayn]Although the article is very well-written, the persistent use of US customary units is very annoying to someone raised with SI units. Yes, it's an American site — which would explain why you'd use both. But not specifying proper, SI units for common measures essentially shows that you really don't care at all about your international readers. Thank you…

The goal. according to the headline, is 1000 MPH - That's not an SI unit measurement. Everything else follows from that premise.

Feeling "left out" is one way to look at this for the writers not doing the math for you. On the other hand, another way to look at it is that the writers assumed you were smart enough to do the math yourself.

The article itself was well written IMHO. It will be interesting to see what comes of these efforts.

 

[lost]

Fatesrider[/url]":1pfu4p08]
The goal. according to the headline, is 1000 MPH - That's not an SI unit measurement. Everything else follows from that premise.

True, and reason they chose 1000MPH is because it looks like another "first".

But, as I mentioned before, that is artificial 'first'. Next would be probably 500 meters/sec followed by 2000KMH followed by Mach 2 followed by 2000MPH or "whichever measurement units give you next round number".

BTW, I do understand why they use it : publicity is main part of these record breaking attempts, and doing anything "first" is much better publicity that just "new record". But I wonder if some real speed "firsts" remain after 20th century.

 

[raxx7]

Mach 1 under water?

 

[lost]

raxx7[/url]":1guvwygr]Mach 1 under water?

Correct, that one would be legitimate "first", and it was not broken in 20th century.

BUT it would require underwater vehicle to break it, and I doubt we will see any vehicle going over 5000kmh under water in this century either ;p

 

[Sobad]

Incredible the engineering that goes into something as "simple" as going 1k on land. The follow on videos of forging the wheels, and testing the brakes are incredible as well.