16 replies to this topic

[BrightStar]

Just a quick 'heads up' if anyone missed the Top Gear rocket launch on Sunday, it's repeated tomorrow on BBC 2 and on Saturday on BBC 3. Well worth watching, although a bit light on technical detail.

The challenge was to convert a Robin Reliant car into a reusable rocket vehicle, Space Shuttle style. I had expected to be fobbed off with SFX, but realised that they might be genuine on seeing an array of Nitrous Oxide tanks filling what may well have been a huge hybrid rocket cluster with a reported 8 tons of thrust. I'm sure I spotted an engineer I met at KLOB, who would have taken it very seriously...

Do watch it in any case, and post responses here

Edited by BrightStar, 21 February 2007 - 08:33 PM.

[Richard H]

Some tech specs are below. I know a couple of the chaps who built it. They did a rather good job!

1/5th scale Space Shuttle.
As a direct replacement for the Orbiter a Reliant Robin was utilised.
From start to launch the project was 4.5 months.

Some technical specs.
_________
Propulsion:
_________

Total impulse well over 200,000 Ns (somewhere in R impulse).
The main propulsion was in 2 stages:
Stage 1: x4 O class hybrid motors + several CTI composites (to offset thrust
asymetry)
Stage 2: Post SRB jettison air start a cluster of x2 O class hybrid motors.
(Active separation utilised x2 pairs of composite motors in the nose of each
SRB)

_____________
Mass Distribution
_____________

Lift off mass: over 1400kg.
Robin mass: circa 250 kg. (of which 40 kg was ballast to provide correct
CG/CP relationship when( although it didn't) the orbiter separated for a
glide to earth.
SRBs: 102 kg each.
External tank: 951 kg (of which around 1/4 tonne was nose weight including
main Ex tank parachute which was 50 kg)
As you can imagine the flight dynamics CG, CP changed with the jettison of
the SRBs so positioning of the 2nd cluster of O motors was important (also
to generate a pitch down moment to assist in orbiter separation)

_________________
Flight profile
_________________


1. Launch.
2. SRB separation and recovery.
3. second stage boost.
4. Orbiter separation and powered glide to earth.
5. Ex tank recovery under a very large cargo parachute (that weighed 50 kg
on its own!).

Items 4 and 5 did not happen. (we had a technical issues with this that we
were all aware of prior to launch, but the show had to go on and decisions
were made, the criteria for a succesful telly programme are, remember,
different from what a conventional rocket launch might be.)

________
Altitude
________

The programme advertised a peak altitude if 3000ft.

___________________
Dynamics and simulation
___________________

A whole world of real pain.
As you can imagine, the variables involved were all coupled.
Thrust asymetry and aerodynamic asymetry were real and significant factors.
All were, however measured and quantified.

To place this into context, the simulation package we developed was
replicated exaclty in the actual flight.

___________
Flight Control
___________

Under boost the vehicle was passively stable.
The vehicle utilised elevons on the orbiter (reliant robin) for glide
recovery.

The SRBs recovered intact under x2 large x-form parachutes.
The O motors were recovered plus various bits of hardware.
The Robin (orbiter and Ex tank were mangled and below surface level)

[portfire]

definitely recommend watching this,i know i will be again

Edited by portfire, 20 February 2007 - 07:13 PM.

[Gary]

Ah, I watched that programme. I found it quite amusing, aswell as interesting- the concept of an old Robin being launched thousands of feet into the air on a liquid fuel rocket. Shame about the ending though- the Robin did not detach itself from the rocket as it was supposed to. Instead of detaching itself from the rocket and gliding back to earth under remote control, the car (plus fuel tanks) plummeted back to earth, leading to quite a big explosion as the fuel remnants ignited upon impact twith the ground.
One day, I hope the UK has the equivalent of NASA, but I doubt it though! Instead, we have the conglomerate known as the European Space Agency.
Has anyone heard of that bloke sponsored by Tate and Lyle- the one who builds his own solid fuel rockets, using sugar as the fuel with potassium nitrate oxidant?

[Mixologist]

It was truly amazing! Does anyone on here, as i see some people know those involved, have a rough idea of cost? I was debating this with a friend and reckoned around the 100k mark but he seemed to think 10 times this, surely Top Gears budget wouldnt stretch that far???

[wayne]

More here:

Reliant rocket...

[Andrew]

That was really funny. Well worth watching it. A bit short of technical stuff like mentioned before but still really interesting.

I wonder if they have heard of redundancy?

[Steve]

I love this forum.

I was pissed off that I missed that. Now I read it's reapeated today, and a quick check shows that it's on at 7pm. It's half six now, best get the valves warmed up

[phildunford]

Thought this was great - pity they did not get separation.

Also very curious to know where the money came from for a project of this magnitude.

Love Top Gear, as it proves there are still a lot of people out there that love doing mad things and are not put off by the 'nanny state'.

[adamw]

3 wheels + NO = lol

Yes, I'd guess the budget to be running into the 100K's (and remember all you license payers: we're funding it!!)

By the way, the explosion at the end is faked (real explosion but not from the impact). You can see on pause / slow-mo that they cut it together.

[Andrew]

By the way, the explosion at the end is faked (real explosion but not from the impact). You can see on pause / slow-mo that they cut it together.

I was going to say that, because it would not just explode. I'm going to have a look for the cut and paste job. I did think "f*ck off" when I saw it explode, and looked at the surrounding area when they went over; guess what, no burnt grass. I reckon it would have been far better to see it get smashed to pieces.

I suppose they thought it would be a far better use of tax payers money to stick in an explosion for entertainments sake.

[Steve]

Items 4 and 5 did not happen. (we had a technical issues with this that we
were all aware of prior to launch, but the show had to go on and decisions
were made, the criteria for a succesful telly programme are, remember,
different from what a conventional rocket launch might be.)

I think this is more important than credit is given to it. I wouldn't be supprised if they planned it this way, it was far more entertainng than landing the robin.
Is there a video available of the real impact? I'll look on utyoube etc

[Andrew]

I looked at the cut and paste job, and it's not very good. Haparently... It explodes about 30' in the air, well it looks like it is slicing into the ground as it disappears over the horizon, and the horizon point is used as the explosion site a good wedge of time later. Good enough to fool most at normal speed. But if you know it definitely will not explode, it was a mixture of disappointment and then the laughter hits you. You can even see the crash site and the explosion site shortly after the crash part of the film in the SAME shot... laughed-mfao at that.

Some high speed footage of it getting smashed up would be cool, but it won't exist. Shame, although just normal footage of its crash would be cool too, hope it gets leaked onto the web.

p.s. nice to see that the forum is that popular now that the bandwidth quota gets exceeded!

[EnigmaticBiker]

"One small stepladder for mankind" Heh
For anyone who missed it some naughty people have put it on youtube:

Edited by EnigmaticBiker, 26 February 2007 - 01:11 PM.

[Creepin_pyro]

There's a torrent of the whole episode here:

http://www.mininova.org/tor/589186

Not that I want to condone downloading copywrited material... but, it's there for the taking.