With a lot of help from our friends, we've made solid progress in the last couple of months.

Testing at 'Airborne Engineering' had already produced a definitive set-up for the rocket motors. But that testing had also shown up some deficiencies with the piston vessels used to push the liquid N2O into the motors. The piston sealing was simply not good enough. The problem was not so much in the running of the systems, but it showed up in the fuelling process.

Fuelling has to be safe and predictable, so something had to be done and that something was a new full set of vessels. The new replacement vessels, made from honed cold-drawn aluminium tube, and with a new piston and seal design, have now been exhaustively tested for both performance and safety. We were able to conduct hydrostatic pressure testing at 'Airborne Engineering' this week and the vessels showed no stress whatsoever at more than twice the operating pressure. Cutting the threads for the high-grade aluminium end-caps requires a level of precision that is beyond the capabilities of our own machine-shop, so our good friends at 'Caswell Engineering' stepped in and did the job on one of their CNC lathes.

Perhaps I should explain what a 'hydrostatic test' is:
Rather than fill the vessels with compressed gas, which represents a huge amount of stored energy that would get very violent in the event of a failure, the vessels are filled with water and then pressurised externally using a special pump. Any failure does not result in a massive bang - rather a soggy (and very depressing) whimper!

The vessels will now go into the car. The nitrogen vessels are being moved to lie in tandem in the chassis in front of the cockpit in order to move the centre of gravity further forward. The space created in the rear-chassis has allowed us to move the piston vessels forward as well. With the driver installed, the Centre of Gravity is now in the ideal spot for straight line stability.

It all sounds a bit boring and technical, but stability at very high speeds is an important thing!

This has all been possible because of the contributions made by 'Bil International'.

Now, with further help from 'Bil International', we are working on a new shroud to streamline the area behind the cockpit (much like a Formula One engine cover), both to reduce drag and to ensure full down-force from the rear wing.

This, we hope, will get the relationship between the Centre of Gravity and the Centre of Down-force just the way we want it.

In the end, much of this has to be thoughtful guesswork, as we don't have access to wind-tunnel testing or high-end computerised fluid dynamics.

We have to make our best guess and test at increasing increments of speed, making adjustments from what we learn from the testing. It's not ideal, but many successful cars were built long before wind-tunnels and C.F.D. were around. If 'suck-it-and-see' was good enough for Art Arfons, it's probably good enough for us.

As the speed goes up, so does the aerodynamic drag. We may have too much wing, we may need new, slicker front bodywork. Downforce is very much needed to enable the car to steer and to keep her on the ground when thrust goes off and the car unloads on its suspension, but we may have overdone the down-force vs. drag equation. We simply don't have a definitive answer as yet.

The offer of the use of wind-tunnel and/or some work on CFD would be very welcome. We've been amazed at how helpful and knowledgable people have appeared on the scene it the last year. so you never know, help with aerodynamics may just pop out of the woodwork when we least expect it.

In the meantime, we're pressing on with the old expermintal method: 'suck-it-and-see'!

Making New Friends

Long time no post on this blog. Life has a habit of taking over, with family matters to deal with and plenty to do, One distraction has been my dear old Dad, who crashed his mobility scooter (going too fast) and broke his femur. Bloody Campbells!! I've simply not spent the time to keep things up to date here.

What have we been up to? Quite a lot!

Money has continued to be tight, so we've stuck to the plan to focus on things that were of the highest import for moving things on.

Rather than spend money on running the car, we've been concentrating on improving the chassis and getting a proper handle on the performance and manipulation of the rocket motors. There has been quite some interest in the rocket motor technology for applications other than going fast on four wheels.

Trouble with these space-rocket folk – they want hard numbers – performance data. We simply have never had the facility to do proper measurement of thrust, flow-rates, chamber pressure and stuff that the scientists need to know. After putting our toe into the strange world of space technology, meeting a few very talented and interesting people and attending a couple of events, we've made some very useful new friends.

James Macfarlane, M.D. of 'Airborne Engineering', and his team at Westcott, have turned out to be a really worthwhile discovery. James has a fantastic facility with fully instrumented testing bays, a well equipped workshop on site and a huge background knowledge and data-base relating to all kinds of rocket motors. He also happens to be a lovely guy, who is patient teacher, with a passion and enthusiasm that is quite infectious. James has a very rigorous and objective approach, which is a good balance to our energy and enthusiasm.

In between conducting testing for companies such as 'Reaction Engines', James has donated time and facilities for testing our systems and collecting the data we need. We have already had one initial day of testing, where we were able to match our systems and testing rig to his rig and instrumentation and to fire a rocket successfully. The rocket we fired was a pretty mild set-up with a small injector, it ran well and gave us some excellent base-line data for further testing. Last week we returned and conducted two further tests. Each rocket was identical to the first test, but each had a progressively larger N2O injector. These were relatively short firings, we'll investigate potential duration at a later date. These firings went very well, with performance conforming to James' predictions and will the usual flat curves for thrust and chamber pressure. Thrust levels and were very good. We think we've arrived at the set-up required for the car.

There was no damage to any part of the rockets.

We are not going to release this data to the general public, I'm afraid, as we have reached a point where we do have to start looking after our intellectual property. Suffice to say, it does appear that we can indeed get these motors to do exactly what is need for the car to fulfil it's potential.

We have also been struggling with castors! The car has a turning radius of an oil-tanker, and is twenty five feet long. So we developed dollies to under her to allow manoeuvring in tight spots (such as getting her out of the workshop!) We've never made them run smoothly and steer easily. It turns out that castors are very subtle bits of simple engineering.

We needed expertise. It arrived in the form of Tim Murrow at 'Bil Material Handling'. I made an enquiry about wheels for our dollies, after doing a bit of 'googling'. We were just looking to buy some of their obviously excellent and strong wheels. When I told Tim what we wanted them for, 'Bil' immediately offered to supply the wheels at no charge. The wheels are great - they glide along like silk. Unfortunately our home-built castors, in which we installed them,, still are very hard to steer. Tim came back with an offer to have their experts review the situation and sort it out for us – again at no charge. Brilliant! What a great company!

We sent them a couple of pics for their company newsletter, they sent us some 'Bil' graphics to go on the car, and now they've offered some very welcome financial support. You just never know when or where your going to run into the right kind of people.

The car will now be on display at their headquarters in Calne in Wiltshire in the 13th of September.

Better Late Than Never!

It's been some time since I last added to the 'Laffin-Gas' blog. David and I took a couple of months off to visit family and friends that are sprinkled around the planet. We visited son, Ken, and his new family in Maui (Hawaii), then our great buddies, Mark and Pav Stacey in New Zealand, followed by David's amazing sister, Judy and my other son. Will, in Sydney and Brisbane.

Last year, we made great strides in the performance and power of the rocket systems with the development of the bi-fuel motor using kerosene as the fuel. Tests indicated that we would be able to achieve around 6,000lbs of thrust from the four rocket motors in the car. With a weight of just under 1,000lbs (minus the all-too skinny driver!) that indicated a power-to weight ratio of 6:1.

A car that can pull 5-6 g under constant acceleration made us re-think where we should be going and what we could possibly achieve. It became clear that, with the right modifications, it would be possible to hit 400mph and get safely stopped on a two-mile runway right here in the UK.

This is a very ambitious and risky venture, of course, but it's a terminal speed that could only be hit using rocket-power. You need to get up to speed in a very short distance (about 1./3rd of a mile) in order to have enough room to get safely stopped. The rocket systems in the car are up to that job.

The car, at present, needs quite a few changes, including new, higher speed, wheels and tyres, more braking power and some new, much slicker, bodywork. We've made a start by enclosing the cockpit and, bit by bit, we're accumulating the new parts to up-rate the chassis from a drag-car to something a bit more capable.

On Thursday 10th June we conducted a final in-car static test of a single kerosene/N2O rocket to confirm that the systems were all working as they should and to be sure that the power we've observed, in test-rig firings, was being re-produced in the car with (all it's extra systems). The test went very well with the car leaping forward against it's tether and the rocket producing a level of power that is quite astonishing for an N2O rocket. You can watch the firing at: youtube.com/laffingastv or click on the icon on our homepage dashboard.

We had decided, last year, that we would only return to running the car when we were satisfied that we would be able to achieve a decent level of reliability. That time has now arrived, so testing can now move from the farm to the runway.

This project has never had outside financial support, so David and I have always had to proceed at a pace that our meagre finances could support.. With the recent recession, and now the massive increases in prices for fuel, power, materials, we've had to go even slower than before. We've tried to concentrate on things that require time, effort and use of all the tooling we already have, rather than on things that require big lumps of cash. We're a bit like the old sit-com; 'The Good Life', only with spanners instead of spades. We're self-sufficient and resourceful, so we can get things done for a fraction of the cost one might expect.

We've done a lot of work on the transporter, which, (with it's generator, compressor, refrigeration units and other kit) is as much a part of going fast as the car itself. One of the biggest jobs was to paint the whole thing white to help the refrigeration units in their struggle to cool gasses and the car on warm summer days. It's made a massive difference and the cooling systems are doing a much better job.

We've also constructed a WW2-style canopy for the cockpit. Having added more ballistic protection behind the driver's head, in the form of a titanium dome, we simply had to enclose the cockpit as we’d turned the entire roll-cage into an air-brake!

On the rocketry side, we've been doing a lot of design work on scaling up to produce a 20,000lbs thrust system for possible use in the ever-growing private space-flight industry. Nitrous oxide hybrid rockets have long held out a promise of cheap and relatively safe rockets for flight, but have never achieved the performance and safety levels needed for the job. Our systems represent a real breakthrough in both performance and safety, renewing the possibility that Nitrous Oxide rockets will be a viable way of getting payloads into space. The car is a wonderful way for little guys like us to demonstrate to the world just what us Brits can do from our back-yards.

There is a way of thinking, these days, that great projects and engineering breakthroughs only come from big companies with big budgets and massive teams of people. When we look at our engineering history we find that much of the really good stuff came out of little workshops and very small, passionate and ingenious groups of people. Ken Tyrrell took three F1 World championships (against the might of firms like Ferrari), working out of a woodshed. Frank Whittle did much the same with his Gas Turbine 'Jet' engines. Colin Chapman started Lotus in a garage behind a pub. So there's no reason why a record smashing rocket-car, and revolutionary rocket technology can't emerge from the machine-shop at the bottom of our garden.

We've now reached a stage where some external financial input is needed. Not a lot, but some. Force India's budget for ONE DAY, would be enough to get us to 400mph! This could be a great opportunity for a company that wants to raise its profile by getting involved with a bit of old-fashioned romance, passion, adventure and engineering achievement. So any one, who would like to come along, 'kick the tyres' and see for themselves if this is for real,get in touch and come and have a butchers!

If you've got an event coming up and would like something to add a bit of spice and interest, why not book us to bring the car along and give an entertaining, sometimes amusing, not-to-difficult talk on our adventures in rocket-science?

New Directions

Our very good buddy, Mike Mathews, commented the other day that we haven’t put anything new on the old ‘Rocket Works’ blog. We’ve been very busy, but that’s no real excuse, so here’s an update:

It’s all change and new directions for the car. A cockpit cover is being made, the front running gear is being changed for different wheels, fatter tyres and bigger brakes. The rear suspension is being strengthened and an additional, very small, parachute is being added. The controls have been moved and the seat position changed to accommodate our new driver. Yes; you heard that right – a new (lady) driver! We made the decision, a few months ago to split engineering and driving duties. It was easier to replace the driver (not that easy, but easier!), so that’s what we’ve done. Her name is Joanna Finch and she’s a very bright and capable woman with a good understanding of engineering and a passion for going fast. (Her regular wheels are attached to a 950cc supermoto – ‘nuff said!).

Two further new members have joined the team, David Lowe an experienced Mechanical Engineer with a back-ground in Aviation and Aerodynamics and Jon London with a lot of experience in rocketry and in education.

David Lowe will be working on improving aerodynamics (including some wind-tunnel work) and making sure that our running-gear is up to the task ahead. Jon will be working both with the rockets and in our educational outreach activities. This takes a huge load off me (Carolynne), now if only someone else could drive the bus…..

We’ve also been doing a lot of work on other applications for our rocket systems. We have met with Professor George Fraser at the Space Research Centre at Leicester University. George is a very interesting man who makes me think of a Scottish version of Dick Keller, (understated, very funny, very commercial and very single minded). George gave us a jaw-dropping tour of his enterprise (and it is an enterprise – not an ivory tower) with room after room of wonderfully engineered stuff, all for the purpose of building payloads to go into space. There was so much neat stainless-steel stuff all over the place. (I should have taken a bigger handbag!).

The upshot of that is we’ve agreed to start on the process of a feasibility study, and then (hopefully) a development programme to do the work to provide a low-cost orbital insertion vehicle. Jon London (who’s passion is rockets for flight) will be in the thick of this process. Many, many thanks must go to Philippa Davies of De Montfort University, whose thoroughness and persistence made this all come together. I’m doing my best to ‘rope her in’ on a more long-term basis. We like having bright women on our team, we do!

I’ve been corresponding and Skyping with a very bright and experienced ex-pat engineer, Geoff Daly, who’s been a great mentor and sounding-board for the last couple of year or so. Geoff has great experience at the highest level in rocket engineering and has his own Consultancy based in New Hampshire in the USA. He’s been very helpful in sourcing up-graded components. He’s also been able to make some real headway in getting to the bottom of what happened in the Mojave Desert, three years ago, when three people were killed and several more injured in an N2O explosion during a test at the ‘Scaled Composites’ facility. His research has given us a lot of comfort, in that it has largely confirmed the conjecture about exactly what kind of event it was and where the mistakes were made. Our safety systems, design and methods have been developed to avoid such an event, so confirmation that we’re on the right path is very well received.

In the course of his efforts, Geoff has talked with many of his contacts and colleagues in the USA, who, it appears, have shown much enthusiasm for our designs, systems and safety methods. Geoff is still pressing on with these matters, so it’s premature to go into very much detail. However, consider this: Mid Afternoon, June, the Mojave Desert, no shade, concrete test-pad, N2O!! Our dear readers can work this one out for themselves, methinks. Keep up the good work, Geoff!

Oh! I forgot – Why all the changes to the car?

400 mph in the UK!!

There you go – I’ve blurted it out.

SECOND OPINION

The following is a short paper by Mark Stacey of Waipu, New Zealand. Mark is a polymath, Engineer, Chemist and Researcher who has worked on many prestigious projects from rocketry to electric vehicles. His is an opinion worthy of respect.



Nitrous oxide hybrid rocket with saturated wick fuel grain and free piston oxidizer tank.
Mark Stacey
Director, CNC Prototyping


Abstract:

A discussion of the many advantages of a hydrocarbon saturated wick feed combustible fuel grain combined with a pressurised piston driven liquid nitrous oxide oxidizer feed.

Introduction:

The use of self pressurising nitrous oxide oxidizer with solid fuel in hobby and commercial rockets is a well known and well developed process however development has plateaued with most development focused on refining the known, i.e. shaping the fuel grain, nozzle development, casing and tank design. This leaves fundamental problems, which have caused accidents and lower than optimum performance, unaddressed. The following describes the significant improvements that have been made to the basic nitrous oxide solid fuel design of rocket.

Oxidizer feed:

Nitrous oxide is a well understood industrial chemical and compared to many oxidizers has many advantages. It is relatively cheap, is relatively unaffected by contaminants, does not require cryogenic handling and is, compared to many other oxidizers, relatively stable. However since the 1930's industrial users have been aware that gaseous nitrous oxide is prone to detonation as temperature rises above ambient.

Most current hobby and commercial rocket motors heat the nitrous oxide to provide self-pressurisation thus putting the oxidizer system into an area where detonation is increasingly likely to occur if shocks or hot spots are present.

Additional problems are:
The density is reduced, so for the same tank volume, less mass of oxidiser is carried.
The tank must have a percentage of free gas space for the initial pressurizing.
Once the oxidiser is flowing, consistent pressure, and hence feed, is uncertain.
As the oxidiser level drops, the flow to the motor becomes a mix of liquid and gas, thereby reducing performance.
The tank always has some residual liquid and gas that is wasted which, in aerospace applications, reduces payload.

The tested solution developed to overcome these problems is a cylindrical oxidizer tank with a free moving piston. The piston is driven down the oxidiser tank by a pressurising gas. The advantages are the nitrous oxide is always liquid both during loading and firing, greatly enhancing operational safety and performance. When discharging to the motor the flow rate is even and the tank is completely emptied.

Fuel grain:

Various fuel grains have been used in nitrous oxide motors, but all previous grains have problems. Hard thermoset plastic grains require careful internal shaping for an optimum thrust profile and are prone to cracking and loss of sections of the grain. In the worse cases this can lead to nozzle blockage and casing failure. Alternative soft fuel grains, such as modified waxes or thermoplastics, allow some compensation for oxidiser flow variations but are prone to erosion with out combustion, reducing motor performance.

The use of a liquid hydrocarbon infused, self-wicking, combustible liner as the fuel grain, overcomes these problems and has additional advantages:

As the motor runs the liquid fuel evaporates from the liner cooling the outside of the liner and thus the case due to the latent heat of evaporation of the hydrocarbon.

The rapid evaporation causes turbulent mixing ensuring the fuel is burnt inside the motor casing.

The motor runs a constant thrust profile as only enough liquid hydro-carbon evaporates to react with the oxidizer flow.

A simple orifice on the oxidiser flow is all that is required for even and complete combustion characteristics.

The liner chosen as the wick is heavy density cardboard tubing. This provides a liner that erodes in a linear fashion for the complete length of the motor. Multiple firings have confirmed this behaviour. As the self ablating and insulating action leaves no hot spots it allows the use of an aluminium motor casing.

Conclusion:

The combined developments of a hydrocarbon saturated wick feed fuel grain, and a free piston liquid feed oxidizer, provide demonstrated safety and performance benefits to the liquid oxidizer solid fuel motor hybrid motor combination.

OPEN LETTER TO DAVID WILLETTS

Dear Mr. Willetts,

Having developed what many in the international world of Rocket engineering see as the best, most cost effective and most innovative Nitrous Oxide Rocket system on the planet, and one that is already producing spin-off technology with wider export potential, I decided to have look at what development support there may be in the East of England.

So I searched and searched for support in such categories as Mechanical Engineering and aerospace technology. On all the sites representing the various Government-funded agencies, form NGOs to Universities I found nothing that fit those categories, except for things aimed at big businesses.

If you’re a small operation, there is absolutely nothing out there.

Here we are, needing to develop high-end engineering capacity and to grow the small-business sector, (the largest sector for employment in the U.K.), and what do we find?
Nothing!

We’ve done more to get youngsters involved in engineering, by taking our rocket-powered car to schools and events aimed at young people, than most others. We recently took the car to the new Ormiston Victory Academy in Norwich, where one of the teachers reckons we inspired up to thirty youngsters to take a real interest in engineering as a career, in one day!

We have had agreements with two universities to work together to develop our technology. Both found it too much work and gave up before we could get started.

If the government wants to promote innovation, the last thing it should do is give development money to institutions and let them pick and choose. Development money has to follow the technology, not the system.

Universities are populated by people on tenure with so much ‘academic freedom’ they can behave as they like with no fear of consequences. Agencies are populated by people from big business who tend to structure their offerings around their own industrial experience. There is no room, or recognition, in this system for the small innovator.

Frank Whittle was a small innovator. Look what we did for him and his little innovation (the GAS Turbine Engine!). Ken Tyrrell took three F1 world championships for the UK, working from a woodshed. Small is beautiful, efficient and creative.

If you want to see what we have, please look at:
www.laffin-gas.com and follow all the links.

One of our spin-offs has world-wide export potential. This is technology we have built and made to work – not simply a nice idea needing money to check it out.

I would like to meet with you, or a senior member of your staff, to go through these issues.

We are true champions of technology education and development who are out there ‘doing’ without help or ‘push’ from any agency or institution. Maybe we are worth a listen?

Cheers

NADINE'S THE STAR!

What a great couple of days we have just spent at the most inspirational school! We were treated to smartly dressed, well-mannered students, (“Can I hold the door open for you Miss?”), great food and one class after another viewing the car and rocket technology asking great questions and showing real interest.

Much thanks must go to their own ‘Rocket Man’, science teacher Rod Stevenson, at whose initial invitation we had decided to attend. Rod’s enthusiasm, energy and commitment to his vocation really inspired us all to step up a gear and do some real teaching! Jon London was in his element, teaching and communicating with the students, and playing with rockets at the same time. Class after class came to see the car, which was on display in a nice toasty-warm building all day on Thursday. The day went by in a blur of activity and energy. I really do think we inspired up to thirty young people (male and female) to think more than seriously about engineering as their future career path.

Several students stood out for their brightness, intelligence and inquiring minds. We do, however, have to single out one very special girl for the finest effort and commitment on the day. The title of ‘Team Laffin-Gas Star of the School’ goes to Nadine Gage.

Nadine was just fascinated with the idea of rockets.

“Can it go to the moon?” she asked. I’d been telling the students all day that there was no such thing as a silly question and, considering Nadine’s age; this was a very good question indeed. We explained that the car was only designed to go a couple of miles at the most and asked her how far away she thought the moon was.

“About five thousand miles” was her answer. I told her that it was much further away than that and asked if she could go and find out exactly how far away the moon really is.

An hour or so later, Nadine was back with the answer. Not only in miles but also in kilometers and pointing out that this distance was, in fact an average. We were impressed. I decided to give her another challenge, namely to find out how far away the Sun is, and how long it takes for the light to get to Earth. I told her she might find out something about the speed of light in the process.

While I was busy with another class, Nadine returned, collared David and told him the correct distances in miles and kilometers and followed that up with the exact speed of light in both units!!

Nadine: You are a STAR!!

In the evening we took part in a Community event with plenty of food and a superb fireworks display in celebration of the creation of this utterly outstanding Academy. After the fireworks it was our turn. With the Head Girl on the button to light the pyrotechnic, Sixth-former Sam and ‘Rocket’ Rod Stevenson on the lanyards, Jon gave the count-down over the PA.

Under my direction, the sequence was cued, with each person doing their bit bang on time and the bio-diesel rocket burst into life with a display of smooth power that we have come to expect. Done!! A live-test firing of a truly serious rocket-motor in a SCHOOL!!

We hadn’t fired our maximum rocket, by any means, but it was still big, loud and proud!! What an honour to be the finale for such a great event!

As our adventure continues, we shall be carrying Ormiston Victory Academy’s logo on our car, and we are sure that this has been the birth of an exciting long-term educational and technological co-operation between the Academy and ourselves.