RE: Bloodhound SSC project enters administration

[Equus]

Zirconium said:

RB Will said:

Quick question just popped into my head. Why does Bloodhound use a car engine as a fuel pump? I'm guessing in the normal system of fuelling a jet engine its just a normal electric pump?

The engine was to power the pump for the rocket fuel (hydrogen peroxide) not the jet fuel, as I understand it.

A more elegant solution would have been to use a turbopump powered by the same HTP that fuelled the rocket motor.

A good friend of mine designed the rocket engine that powered this, using the HTP turbopump solution:



But hey, why rely on mundane old 1950's technology, when you can do something groundbreaking like using a couple of hundred kilos of entirely separate powerplant and fuel supply to do the same job?

[IN51GHT]

Equus said:

A more elegant solution would have been to use a turbopump powered by the same HTP that fuelled the rocket motor.

A good friend of mine designed the rocket engine that powered this, using the HTP turbopump solution:



But hey, why rely on mundane old 1950's technology, when you can do something groundbreaking like using a couple of hundred kilos of entirely separate powerplant and fuel supply to do the same job?

He should talk to the remaining team then, it is something we looked at & came out as a pretty much perfect solution. but the development costs were too high as we had no experience of turbopumps, nor did we have access to anybody who did. After all, apparently everyone who is on the team is an overpaid millionaire, so he could make a killing!!!!

Edited by IN51GHT on Friday 19th October 11:16

[Stoned]

Scottie - NW said:

I normally enjoy engineering programs and challenges, but I just don't get excited about this project. Essentially it's a jet engine with wheels that you have to keep straight and on the ground, it's not car based really.

Good luck to those who enjoy it, perhaps you are seeing something i am not.

I 100% agree. This just isn't a 'car' to my mind. If the wheels were being driven I'd be excited, but I'm not it's basically a frame being pushed by an aviation jet engine. What's a 'car' about that?

[Equus]

IN51GHT said:

He needs to talk to the remaining team then, it is something we looked at & came out as a pretty much perfect solution. but the development costs were too high as we had no experience of turbopumps, nor did we have access to anybody who did.

Interestingly, the DeHavilland Spectre (the engine in the aircraft pictured above) appears to be not dissimilar in basic specification to the Bloodhound's.... Google suggests that the Bloodhound's motor was 30kN thrust?; the Spectre was 35.7kN.

It was also fully tested and cleared for manned aviation use, back in the day, and as such was fully throttleable and capable of in-flight re-starts, which I suspect that the hybrid rockets in Bloodhound would struggle with.

My friend had no experience of turbopump design, and no access to anyone who did, either. He worked out the knowledge for himself (without pocket calculators, much less CAD, FEA and CFD to fall back on). He's very much retired, these days, of course - the Spectre was designed in the early 1950's - but was in his 20's when he was in charge of that project.

[LordGrover]

IN51GHT said:

I left of my own accord after Newquay test runs, I had issues with the project I wished to discuss with the management, nobody was willing to discuss so I left with a clear continence as I stand by my principles.

[IN51GHT]

LordGrover said:

IN51GHT said:

I left of my own accord after Newquay test runs, I had issues with the project I wished to discuss with the management, nobody was willing to discuss so I left with a clear continence as I stand by my principles.

Whoops.

[Mave]

RB Will said:

Quick question just popped into my head. Why does Bloodhound use a car engine as a fuel pump? I'm guessing in the normal system of fuelling a jet engine its just a normal electric pump?

Jet engines normally have mechanical pumps driven off the engine gearbox (rated in handfuls of HP rather than hundreds!)

[IN51GHT]

Equus said:

IN51GHT said:

He needs to talk to the remaining team then, it is something we looked at & came out as a pretty much perfect solution. but the development costs were too high as we had no experience of turbopumps, nor did we have access to anybody who did.

Interestingly, the DeHavilland Spectre (the engine in the aircraft pictured above) appears to be not dissimilar in basic specification to the Bloodhound's.... Google suggests that the Bloodhound's motor was 30kN thrust?; the Spectre was 35.7kN.

It was also fully tested and cleared for manned aviation use, back in the day, and as such was fully throttleable and capable of in-flight re-starts, which I suspect that the hybrid rockets in Bloodhound would struggle with.

My friend had no experience of turbopump design, and no access to anyone who did, either. He worked out the knowledge for himself (without pocket calculators, much less CAD, FEA and CFD to fall back on). He's very much retired, these days, of course - the Spectre was designed in the early 1950's - but was in his 20's when he was in charge of that project.

Like I said, we lacked the budget to develop our own.

[Equus]

IN51GHT said:

Like I said, we lacked the budget to develop our own.

Absolutely.

Which is the point I'm trying (apparently without much success) to get across to Mave.

[Mave]

Equus said:

IN51GHT said:

Like I said, we lacked the budget to develop our own.

Absolutely.

Which is the point I'm trying (apparently without much success) to get across to Mave.

No, I understand that you have to work to a budget. I also understand that its equally important that the thing you are designing needs to be able to meet its objective - the point I have been trying (apparently without much success) to get across to you. Guess what, if you don't demonstrate credibility, you don't get the money to try again! The skill is being able to work out which technologies are fundamental to meeting your objectives versus which ones help meet your objectives but at high levels of risk and cost.

[Mave]

Equus said:

Mave said:

.....having moved the game on so far that no other horse has taken the record since the 80s. Compared to previously when the record was changing hands regularly.

Not really. There had been a fit of activity in the 1960's, with the jet battle between Breedlove and Arfons, but that had been over for 20 years, and prior to that the record stood from 1947 to 1963.

The Breedlove-Arfons battle was very much the exception to the rule. After that, and Blue Flame, there had been no real interest.

You used those very examples as illustrations of the benefit of an evolutionary approach. Times when the records were regularly changing hands. so are those examples representative to illustrate your point, or are they an exception to the rule?

Equus said:

Mave said:

Equus said:

Thrust II was designed with transonic speeds in mind, and Thrust SSC, at least, was designed to go supersonic from the outset. With a little forethought they could have designed a basic concept that was fundamentally capable of development throughout the necessary speed range.

So which is it - should they have evolved from previous designs cheaply, or taken a more expensive fresh design capable of higher speeds from the outset? You can't have it both ways!

I don't want it both ways: if you know you're going to have to run at least at transonic speeds to take the record (bearing in mind that the last three contenders had been designed to go supersonic), it would have been sensible to design for supersonic, from the outset.

In fact, Noble knew that Thrust II was only just capable of scraping the record, even as he was having it designed and built.

Designing to supersonic speed from the outset is very different to designing to evolving a transonic concept (the very approach you were advocating!). History shows that his balance of ambition and risk appetite was about right.

Equus said:

Mave said:

So if it was all doable so long ago (when I would argue that we may have understood some of the aero, but not necessarily known what to do about it!) why hasn't anyone done it?

You remember what I told you the most important factor was?

Edited by Equus on Friday 19th October 12:39

You might have told me that but I don't agree with it. The amount of money spent on significant redesigns since the 1970s far exceeds how much it would have cost to run blue flame with metal wheels, or run the Budweiser rocket again.

[Equus]

Mave said:

Designing to supersonic speed from the outset is very different to designing to evolving a transonic concept (the very approach you were advocating!).

You do understand that to get to supersonic speed, you have to go through the transonic range?

If you work to a design concept that's capable of going supersonic (which we've known how to do since at least the late 1960's), then it's automatically going to be capable of dealing with the transonic regime.

I'm not sure whether you're being deliberately obtuse, or whether you're just not very bright, but what I was advocating was that a design concept should be adopted at the outset that is capable of evolution; ie. a shape and chassis arrangement that is stable and efficient at all speeds up to supersonic. It's not critical if it doesn't have sufficient power at day 1: that can be added by upgrading or reheating the engine, or adding rocket boosters (as Bloodhound intended).

....but it avoids you having to go through the pain (and huge cost) of developing entirely new chassis, aerodynamics, control systems, operating procedures, etc., etc., for completely new designs each time, as Thrust II/Thrust SSC/Bloodhound have had to do.

[Dr Jekyll]

Equus said:

You do understand that to get to supersonic speed, you have to go through the transonic range?

Obviously.

Equus said:

If you work to a design concept that's capable of going supersonic (which we've known how to do since at least the late 1960's), then it's automatically going to be capable of dealing with the transonic regime.

It isn't that simple.

To give one example. A wing whether for lift or downforce in supersonic airflow effectively functions as if it's been moved further back compared with subsonic airflow.


Being able to stay level in those two regimes doesn't mean you will stay level in between the two, with some airflow over the vehicle supersonic and some subsonic. Not a problem if an aircraft bounces up and down a bit, though a great of trouble went into minimising it for Concorde, but a big issue for a land vehicle.

Edited by Dr Jekyll on Friday 19th October 14:08

[mcdjl]

Equus said:

You do understand that to get to supersonic speed, you have to go through the transonic range?

If you work to a design concept that's capable of going supersonic (which we've known how to do since at least the late 1960's), then it's automatically going to be capable of dealing with the transonic regime.

I'm not sure whether you're being deliberately obtuse, or whether you're just not very bright, but what I was advocating was that a design concept should be adopted at the outset that is capable of evolution; ie. a shape and chassis arrangement that is stable and efficient at all speeds up to supersonic. It's not critical if it doesn't have sufficient power at day 1: that can be added by upgrading or reheating the engine, or adding rocket boosters (as Bloodhound intended).

....but it avoids you having to go through the pain (and huge cost) of developing entirely new chassis, aerodynamics, control systems, operating procedures, etc., etc., for completely new designs each time, as Thrust II/Thrust SSC/Bloodhound have had to do.

I seem to remember Richard Noble saying at a talk that they'd done some re-sims of Thrust SSC when they were looking at Bloodhound initially. Those suggested that SSC was within about 10-15mph of becoming airborne at its max speed with inevitable consequences, something they'd thought they were along way clear of when SSC was run. Managing the air under the car as i understand it was/is one of the major challenges. As it was SSC did a 'hop' to one side as it passed through the transonic range.

[Equus]

Dr Jekyll said:

Being able to stay level in those two regimes doesn't mean you will stay level in between the two, with some airflow over the vehicle supersonic and some subsonic. Not a problem if an aircraft bounces up and down a bit, though a great of trouble went into minimising it for Concorde, but a big issue for a land vehicle.

For sure.

And making certain that your design is stable in both regimes and during the transition is one of the challenges for supersonic vehicles. Certainly, it's one that you don't have to address if you have no plans to go supersonic, but to do so 'future proofs' the design and avoids the massive development costs of an entirely new vehicle which have now, predictably, killed the Bloodhound project.

[Mave]

Equus said:

Mave said:

Designing to supersonic speed from the outset is very different to designing to evolving a transonic concept (the very approach you were advocating!).

You do understand that to get to supersonic speed, you have to go through the transonic range?

Yes thanks. I don't understand why my comment would make you think otherwise.

Equus said:

If you work to a design concept that's capable of going supersonic (which we've known how to do since at least the late 1960's),

No, we haven't. As shown by the lack of demonstrable evidence until the mid 1990s

Equus said:

then it's automatically going to be capable of dealing with the transonic regime.

And much more expensive and a riskier proposition, the very things you are trying to avoid

Equus said:

I'm not sure whether you're being deliberately obtuse, or whether you're just not very bright,

Or just maybe I happen to have a different opinion and experience base to to you on this subject

Equus said:

but what I was advocating was that a design concept should be adopted at the outset that is capable of evolution; ie. a shape and chassis arrangement that is stable and efficient at all speeds up to supersonic. It's not critical if it doesn't have sufficient power at day 1: that can be added by upgrading or reheating the engine, or adding rocket boosters (as Bloodhound intended).

Which assumes you already know how to design a stable and efficient supersonic platform. Which you don't until you've built something and got close enough to test it.

[mcdjl]

Equus said:

A more elegant solution would have been to use a turbopump powered by the same HTP that fuelled the rocket motor.

A good friend of mine designed the rocket engine that powered this, using the HTP turbopump solution:



But hey, why rely on mundane old 1950's technology, when you can do something groundbreaking like using a couple of hundred kilos of entirely separate powerplant and fuel supply to do the same job?

Just looked that up. It was cancelled in 1960 having cost nearly £6million. Thats about £130million now.I think Bloodhound would be more broke had they tried, though wonder how much Mamco have spent?

[Mave]

Equus said:

For sure.

And making certain that your design is stable in both regimes and during the transition is one of the challenges for supersonic vehicles. Certainly, it's one that you don't have to address if you have no plans to go supersonic

Bearing in mind we're talking about LSR vehicles, that's something you have had to address for the last 30 years...

[Equus]

Mave said:

Equus said:

If you work to a design concept that's capable of going supersonic (which we've known how to do since at least the late 1960's),

No, we haven't. As shown by the lack of demonstrable evidence until the mid 1990s

Budweiser Rocket went supersonic (or as near as makes no difference, if you dispute their figures) in 1978. It was based on the Blue Flame design, which was evolved in the late '60's.

As I've said before, the whole 'boldy stepping into the unknown' bks is just blarney for the media. Look at the shape of Bloodhound, or any other car properly designed to go supersonic and you'll see that its actually very simple and straightforward. Compared to the aerodynamic complexity of, say, a current F1 car, it's not even in the same league.

You don't have to test, to have a pretty good idea that something will work: there has been enough research done by NASA and others on supersonic aerodynamics that it's now quite predictable.

Mave said:

Bearing in mind we're talking about LSR vehicles, that's something you have had to address for the last 30 years...

There, at last, we agree on something. Yet bizarrely, Thrust II chose not to (it was consciously designed to only be acceptable up to high transonic speeds), and Thrust SSC chose to use a design that was known to be sub-optimal and marginal in its stability when supersonic.

We've known for ages that the answer to managing the reflected shockwaves is to use a long, slender 'delta' planform. Blue Flame knew it, as did SMI Motivator, Budweiser Rocket, Bluebird CN8, Blue Star, Spirit of America Formula Shell, etc., etc.

Bloodhound SSC, correctly, adopted the same, simple approach.

Why they chose to tread a different path with Thrust II and Thrust SSC is anybody's guess: they could just as easily have adopted something similar to Bloodhound's design at the beginning... as the list of cars I've quoted proves, there was no shortage of precedent.

[Mave]

Equus said:

Mave said:

Equus said:

If you work to a design concept that's capable of going supersonic (which we've known how to do since at least the late 1960's),

No, we haven't. As shown by the lack of demonstrable evidence until the mid 1990s

Budweiser Rocket went supersonic (or as near as makes no difference, if you dispute their figures) in 1978. It was based on the Blue Flame design, which was evolved in the late '60's.

One example of a vehicle that nearly went supersonic in the late 70s and was just about out of control at that point is not evidence that we've known how go supersonic since the late 60s, no matter how you spin it.

Edited by Mave on Friday 19th October 15:29