UKPS Videos

I’ve put together more videos for the UK Pyrotechnics Society this year, from the AGM meeting in March. Editing was a little easier this year as I’m a tiny bit more familiar with Final Cut Express and only had 2 cameras this time with identical resolutions. We had no special lighting so they are a little grainy after the brightness tweaks in FCE, but not too bad.

I also decided to improve them this year by using a separate sound recorder, as the audio was a big issue last year. I bought a basic Sony ICDBX112 digital dictaphone and some great value lapel mics from Amazon. Unfortunately the recorder doesn’t have a digital out, so I had to transfer the recordings to my laptop using the headphone out on the dictaphone and mic in with a 3.5mm audio conector and Audacity, a bit old school!

As most of the speakers had powerpoint presentations I decided to overlay those onto the videos too. Trying to read the content on the video directly was tricky in some places due to quality and lighting. I managed to export the keyframes of each presentation as PNG files and then overlay and position them in bulk onto the videos. It took a little time to adjust all the timing so they show at the right points, and all the animation/transitions are lost, but I think this makes the videos much more useful to interested viewers.

Chris Clarke on Pyromusical Design

Chris Clarke on Firing Systems

Steve Miller on Pyromusicals


The World’s Largest Core Burner

This article was published in Issue 10 of SPARK (Summer 2012), the official newsletter of the UK Pyrotechnics Society. If you’re interested in pyrotechnics please check them out and maybe even join up.

Space Shuttle SRB diagramOne year ago saw the final launch of the NASA’s Space Transportation System, the Space Shuttle, which was retired after 30 years of service. The propulsion system of the Space Shuttles consisted of three main liquid fuel powered engines (liquid hydrogen and oxygen), and a pair of reusable solid rocket boosters (SRBs) which provide the additional thrust required at take-off to escape earth’s gravitational force. These SRBs, despite their immense size and added features, use the same basic principles utilised in the firework rockets we are more familiar with.

The SRBs are a well recognised feature of a Shuttle before launch; the two white tubes straddling the huge external orange liquid fuel tank on which the Shuttle piggybacks during launch. They are manufactured primarily by ATK Launch Systems in Utah, with parts supplied from many other contractors.

Each SRB stands 149ft (45.5m) tall, and weighs 1.3m lbs (590,000kg) before launch, which drops to around 200,000 lb (91,000kg) when fully burnt. The actual motor section is 126ft (38.5m) long and 12ft (3.7m) in diameter. The outer steel casing is built in separate segments, which are assembled at the launch site and, as well as the motor itself, also house the electronics, recovery parachutes, separation gear, and a self-destruct system. They are the largest solid rocket motors ever flown, and were the first designed for reuse. Their modular and reusable nature also means that different configurations have been planned for use in other NASA programs including the (now scrapped) Ares I and Ares V, and the Space Shuttle’s upcoming replacement, the Space Launch System (SLS), due for launch in 2017.

The SRB fuel is a solid mixture referred to as Ammonium Perchlorate Composite Propellant (APCP), with the composition: Ammonium Perchlorate (oxidiser – 69.6%), Aluminium (fuel – 16%), Iron Oxide (catalyst – 0.4%), Polymer binder (PBAN or HTPB – 12.04%), and an Epoxy curing agent (1.96%). Each SRB contains 1m lbs (450,000 kg) of the composition, which is mixed in 600 gallon bowls before being cast into the required segments, just slightly more than is allowed under our 100g rule! The cured propellant has the consistency of the eraser on a pencil, and is a form of synthetic rubber.

STS-134 solid rocket booster segment stacking

Segments of the motor being joined, with the hollow core visible

A hollow core is used in the rocket to increase the surface area of the burning fuel, exactly the same as in black powder core burner rockets. In this case however, the first segment of the motor has an 11-pointed star shaped core, giving a hugely increased surface area for the initial (launch) stage of the burn, with the remaining three segments being a traditional cone shape. As the rocket burns the star softens out to a more circular shape. This configuration gives maximum thrust during the initial launch stage, after which the thrust  drops off to about two thirds to prevent over stress as the Shuttle experiences it’s maximum aerodynamic stress (“Max Q”).

As expected with solid fuel rockets, once ignited they cannot be extinguished, so the SRBs are only ignited as the final step of the launch sequence, as the countdown clock reaches zero. The other three main engines on the Shuttle are started around 6 seconds earlier, and must reach 90% thrust within 3 seconds (as well as some additional checks), otherwise a safety shutdown procedure will automatically end the launch and the SRBs will not be ignited. Ignition of the rockets begins with a PIC capacitive discharge system, charged to 40 volts, which must receive three simultaneous fire signals from the various computers controlling the launch. When initiated the charge starts the chain reaction of ignitions building up to the final ignition of the main composition. A series of NASA Standard Detonators (NSDs) are first to detonate, which ignite a booster charge, which then ignites an ignition initiator, which finally ignite the main propellant! At the same time the pyrotechnic bolts fixing the boosters to the launch platform are also fired, leaving the shuttle completely detached and free to launch.

STS120 Launch

Shuttle launching, with the SRBs providing maximum thrust

Each SRB generate around 3.1m lb (14 MN) of thrust at their maximum (a few seconds after launch), and together provide around 83% of the total lift off thrust for the Space Shuttle. Two minutes into the launch, at around 146,000ft (44.5km) and Mach 4.5 (3,425mph), the rockets are jettisoned from the Shuttle, but continue to rise for around another 75 seconds to their apogee of approx 220,000ft (67.1km). As they start to fall back to earth, parachutes are deployed and they will land in the ocean and around 140 miles from the launch point, and will float upright with around 30 ft sticking out of the water. They are recovered by ship and the major parts will be refurbished and refilled for reuse in another booster rocket.

The simple core burning principle helped launch a total of 135 Space Shuttle missions, which carried numerous satellites, probes and experiments into orbit, launched the Hubble Telescope, and enabled the construction and servicing of the International Space Station. In 1986 a failure of one of the SRBs during launch led to the disintegration of Space Shuttle Challenger, killing all seven crew on board. It was later found that an O-ring used where the segments of the SRB are joined had failed due to cold weather, allowing the exhaust gases of the motor to escape through the side of the casing, and subsequently burn through the casing of the main liquid fuel tank.

British Firework Championships 2010 Review

This article was published in Issue 7 of SPARK (October 2010), the official newsletter of the UK Pyrotechnics Society. If you’re interested in pyrotechnics please check them out and maybe even join up. And apologies it’s so long, I already cut it down once!

The British Firework Championships have been taking place in Plymouth on the south coast for the last 14 years. As a joint effort between Plymouth City Council and The Events Services Association (TESA), it is now one of the biggest firework events in the UK, attracting tens of thousands of spectators from across the country. And best of all it’s free!

The event takes place over two days, with six firework companies competing to put on the best display. They each have a 500kg Net Explosive Quantity (NEQ) weight limit for their fireworks, a strict 10 minute display time, and various other rules and limits on things like the angle of mortars. Three teams fire on each night, while a panel of six judges (three local and three industry experts) watch and mark them. In addition to the display itself, 20% of the judges’ marks are awarded on behind-the-scenes things, such as submission deadlines for paperwork, site layout, sticking to their firing order, and behaviour on site. With every team doing their best to put on a great show, the competition can actually be won or lost on a few important points before the fireworks even start!

In contrast to the increasing number of displays that are being cancelled each year due to financial cutbacks, the Plymouth shows are now bigger than ever. And in the face of critics of council spending, Plymouth Councillor Peter Brookshaw was keen to point out on the local news that the event actually provides a massive financial boost for the city. It costs the council roughly £90,000 to stage the event, but brings in an estimated £4million to the local economy, so the event looks set to continue for some time to come.

Day 1

Display SiteI’ve never been to the event before but this year I decided to head down country and take a look. As it’s the biggest display I’ve been to I though it’d be good to write something about it  for Spark. I also contacted the organisers, who very kindly arranged for myself and a friend to visit the firing site during the daytime setup, to get some behind the scenes photos, and hopefully have a chat with some of the teams. Although I’ve been on a few firing sites before, this would definitely be the biggest, and so I was pretty excited at the prospect.

My good friend Kristy Flowers travelled up from Cornwall and brought along her digital SLR camera equipment (which is much better than my little compact thing), and so she became my official photographer for the two days!

As soon as we arrived I could see straight away why Plymouth makes such an ideal location for the championships. The promenade and large open grass banks, known as the Hoe, slope down and face out over River Plym. The display site is about 400m out in the water, set out along a breakwater which sticks out from Mount Batten on the opposite bank. Because the firing site is surrounded by water, there are no concerns about fallout causing fires in any surroundings, or anyone getting too close. The Hoe spans a wide distance, giving spectators a great view across the river from all along the front, without needing to be too crowded at any point. High up on the front is also Plymouth Citadel, which looks out directly over the water to the display site. This is where the judges for the competition are situated, giving them the best possible view.

Although you can see the display site just a few hundred metres across the water from the Hoe, it’s actually a good 5 mile round trip to get to it, which took us a while to find, navigating through all the small villages and back roads. When we arrived at the site we went to the security gate to meet Avril Di Palma, who was arranging out security passes. Avril works for Davas Ltd, an explosives consultancy agency, who were in charge of site security and safety, the official radio communications and countdowns for the teams, and were also helping with the adjudication of the event. She issued us our passes and we were then free to go and see the first day’s teams setting up. We introduced ourselves to the head of each team, and they all kindly agreed to let us take photos of them while they were busy getting the displays ready, and the occasional bit of posing for good measure!

The weather was pretty poor, with rain and wind attacking form all sides, as well as a very low fog threatening to hide a lot of the aerial effects that night, but the teams were in full swing setting up their display areas. As the breakwater is long and narrow, each team had about a 40m stretch to set up along, while keeping a 3m clearance behind them for all their vans to get through. There were generator powered floodlights ready for the clear up later that night, and each team had been provided with a large pallet full of sand bags, to use as ballast to weigh down and hold up all their mortar racks and other equipment.

First up was Essex Pyrotechnics, and their main man Tom told us they were keen to make a big impression having drawn the short straw to be the first team firing. They had an almost entirely shell based setup at that time, with a wide range of sizes from 3 inches all the way up to a pair of 12 inch mortars, although a selection of candles and single shots would be following later. They were using the Pyromate firing system, as were the other two teams that day we would soon find. He was particularly excited to be firing some very large and loud salutes, each containing 1kg of powder, and surprisingly manufactured here in the UK at their own Cambridge factory.

Roman Candle fusing1st Galaxy Fireworks, based in Nottingham, were going to be firing second, and were also well underway with their setup, most of it by this time covered in plastic sheeting to fend off the rain. I chatted to Lee from the team who told us they were firing wirelessly for this show, as it gives them improved safety distances and allows them to position themselves in the best spot. As with Essex, most of their material was their own manufacture, except some 10 inch Spanish shells which would be their largest size fired.

The final team firing on the first night were Reaction Fireworks, based in County Durham. They were busy finishing fusing of their shell leaders and foiling over the mortars. They had a large selection of Cat 4 cakes set out, which were the first we had seen of the three teams. These included a Lidu 2.5 inch x 36 shot ring shell cake, which is probably be the largest bore cake I’ve seen “in the flesh”.

Loading shellsOther than the sheer amount of mortar tubes and other custom racking being set up, the main thing that struck me was how very different the three teams’ sites looked. Obviously you expect the actual displays to look different, but I’d assumed there would be more similarity between the amounts of different types of fireworks they would be using. The first team were mainly mortar based, the second team had a large amount of roman candles and other single shots, and the third team had a lot of cakes.

I also saw a couple of fusing techniques I had not seen before at the smaller sites I have visited, such as Chinese time fuse being used in-line with quickmatched chains of shells to give time delays without using up extra electronic cues. There were also a few time delay tubes (which I’ve since found out are called Pyroclock), which consisted of a semi-opaque plastic tube with some sort of timing composition within it. It was fused with an e-match at one end and then had quick match leaders coming out of it at regular intervals along its length. It reminded me very much of how a roman candle works, and would again give some delays between shell launches.

Night 1

FairgroundWe headed for our chosen spectating spot about an hour before the displays were due to start, and squeezed ourselves in among the dozens of other photographers who had picked the same spot. As Kristy had not photographed fireworks before, she had been busily reading up on it, including Richard Harwood’s article on the subject from a previous issue of Spark, which proved incredibly useful to give us a starting point for experimenting with various settings.

The fog had finally lifted and the rain was holding off which was good for the fireworks, although it was still quite cold. I think the earlier rain had already put some people off coming as it didn’t get quite as busy as we were expecting. Up on the promenade there was a fairground in full swing, as well as a live music stage presented by the local radio station. Firework Fan and Water CakeObviously this attracted the younger people, and had a very lively atmosphere in the run up to the fireworks. There were also the usual burger and donut vans dotted all over for those in the need of some artery clogging, as well as a much appreciated coffee stall given the cold weather! People had positioned themselves all along the front, many bringing picnic blankets and fold out chairs to get comfy.

At 9.45pm exactly, the first maroons went up, which each team had to fire to signal the start and end of their displays. Essex Fireworks opened the proceedings and certainly stuck to their idea of big and loud; their finale ended with a huge barrage of their bright loud salutes that certainly got everyone’s attention! 1st Galaxy’s display took a less aggressive approach and moved slower, with nice visual patterns and sequences. Blue and white shell burst over waterReaction Fireworks then closed with, in my opinion, the best of the three that night; a great combination of visual appeal but still with plenty of noise. Kristy’s favourite of the night were 1st Galaxy, so it just goes to show how different people appreciate different aspects of the same firework display.

I won’t try and describe each display in any detail as it’s a little difficult in words, but you can see the best of our photos and videos at the web addresses given at the end.

Day 2

Shells waiting to be loaded into mortarsOn the second we visited the display site again mid-afternoon, and thankfully the weather this time was glorious.

Flashpoint Fireworks would be firing first, and Jason from the team told us they were hoping for a good result after winning the Firework Champions competition at Eastnor Castle last year. He said all the teams had been busy setting up since 7am, but still had plenty to do in the remaining few hours. He was particularly looking forward to firing a special 10″ Yung Feng shell which had set him back £140! They were the first team we saw using MLE’s FireByWire system, which they had started using relatively recently.

SM Art Pyrotechnics were second along, and we hadn’t failed to notice before we even arrived on site that they had something a little special lined up. In the centre of their display was a huge set piece wheel, which must have been 20 feet in diameter. It was adorned by numerous fireworks, and supported by a heavy duty scaffold tripod, which itself was lined with roman candles and huge gerbs. We spoke to their team lead Steve about the set piece, which obviously they were quite excited about, especially being the only set piece in the whole competition. Giant wheel set pieceApparently they had also only used it once before, and that had been with a smaller diameter. They had now extended it further, so tonight would be the first time they would see it in full action themselves. Other than that they obviously had the usual collection of mortars, up to a single 12 inch, and a massive amount of fanned single shot comets and other effects. I was also impressed by all the racking for their mortars and fanned single shots; most of it looked brand new and was all of painted metal construction giving a very professional look.

Last but not least were Star Fireworks, who seemed to be making good use of their surroundings. They had cakes set up on the stone benches, and plenty of fireworks strapped to the waterfront railings, some of which we would later find out were water cakes.

Chatting to one of the Star Fireworks guys, we foundout another important reason why Plymouth is such an ideal location for the competition. The local Naval base makes an ideal secure overnight storage place for the fireworks, allowing teams to travel down a day or two before their display.Single shot fanned racks

He told us that it had been quite a unique experience arriving at the base the previous night. Obviously taking explosives into a Naval base has to be taken very seriously, not least because the Navy will be storing a lot of their own ordnance there. When the teams arrived all of the vehicles were closely inspected, along with their paperwork and ADR hazardous good driving licences. But most interesting was that upon arrival they had to have a 10-minute cooling off period before they were allowed out of their vehicles!

Night 2

Crowds gather on Plymouth HoeThis time we arrived at our spectating spot 2 hours before the displays were due to start, to try and beat the other photographers. The good weather was certainly making a difference, we were some distance down the front from the main hustle and bustle of the fairground but even at that time there were noticeably more people gathering around than the previous night.

By the time the sun was finally setting the crowds had grown massively, and every patch of grass bank and path was awash with blankets, chairs and people, settling down for the shows. The fairground was swarming as local acts danced and sang on the music stage, keeping everyone entertained until the fireworks.

Pink shell burstsFlashpoint started with a great opening sequence; their display seemed to consist of a series of 45 second to a minute individual sequences, giving constant changes without looking disorganised. A definitely impressive start and the crowd reactions were certainly much louder than the previous night. However, at the end of their display there appeared to be a small fire on the site, which was quickly put out. There was then a longer than planned delay, and lots of activity down on the firing line, before the second team started.

We wondered at the time if they were having some technical issues, and at several points through SM Art’s display it was apparent that not everything was firing. Some of the sequences that should have been symmetrical only fired on one side leaving big voids in the sky. This was a real shame as they had some of my favourite individual effects of the whole night, and it was great to see their huge set piece in action, even though it didn’t rotate in the end, as it was something that really separated them from the other teams.

We found out later that they had indeed had some issues, and apparently fallout from the previous team’s display had ignited some of their material prematurely, despite the precautions all the teams take against this. This was incredibly unlucky for them and they must have been pretty disappointed, however it seemed that most spectators around us weren’t aware of the apparent problems, and still enjoyed their display.

Star Fireworks' finale sequenceLast up were Star Fireworks, and they certainly went all out. Their display was incredibly well organised with fantastic effects and sequences throughout. At one point they had a series of bright coloured flares along the front, all different coloured as opposed to the common single colours. Then suddenly the water itself lit with bright floating flares of all colours, from their water cakes we had seen earlier. This was incredibly effective as the rainbow of colours floated out across the water; the effect was not lost on the crowd! They finally ended with an all-white finale sequence that lit up the sky with bright glittering and slow falling effects, a fantastic sight. The cheering that followed summed up the quality of their display, and it seemed unanimous among the crowd that they should win the competition.

Star Fireworks were indeed crowned the championship winners (which we both completely agreed with), with Reaction Fireworks and 1st Galaxy Fireworks taking 2nd and 3rd places respectively. Star Fireworks went on to also win the Firework Champions event at Belvoir Castle less than two weeks later!

We had a great time over the two days, learning lots  about large display sites, and of course seeing some great fireworks. Thanks to Kristy for her brilliant photography and putting up with all the pyro talk! Thanks to Avril for letting us look around the site and filling us in on some of the competition details, and also to Kevin Minton from TESA, for arranging our site visit.