The Jet Powered
Blimey, it’s a strange story! The idea started during an ill-fated cycling comeback. I was shopping around for a cheap heart rate monitor and the word ‘pulse’ ended up on a Google search. A few pages about ‘pulsejets’ appeared and I think I spent the rest of the day researching them. I found a patent filed by the original inventor of the valveless pulsejet, a bloke called Ray Lockwood, which included a drawing of one. I zapped one together from a sheet of scrap 304 stainless in the shed (it used to be a kitchen worktop) and built the fuel and electronic starter system. Before it was even finished, I knew I needed something to propel with it. Sue suggested half-seriously, “how about a shopping trolley ha ha ha…”
There was one lying in the stream beside the path where the kids walked to school. Hmmm… It got dragged out on a clandestine raid later and wheeled into the shed…
There is a particular technique for starting a valveless pulsejet – it’s a matter of getting the air and fuel mix j-u-s-t right. My mate Tony was my chief starter and got fried on several occasions. But the first time it went, MY GOD! It was apocalyptically loud with a blast radius of several metres. The garden took ages to recover from the singeing. The next day it was time to run it at the airfield. I’d tried to keep it lowkey but a sizeable crowd appeared in no time. The first run identified some pretty harrowing handling defects although my first problem was baling out in a hurry when the wooden seat spontaneously ignited in the heat. The onlookers had tried to tell me I was on fire but I’d misinterpreted their gesticulations and simply replied with lots of EXCITED FLICKING OF THE V'S as I buzzed past.
The Trolley running flat out during a static test. I think this was the first time I'd got it to run properly on liquid fuel (red diesel)
After a few mods, the trolley was coaxed up to a terrifying 52mph running on kerosene instead of LPG but it then got into a scary oscillation and threatened to roll over, so I bottled it. That was as fast as it ever went.
I’d cut my teeth on this project and now set my sights a little higher, literally. I set about a pretty involved R & D programme in the shed with the ultimate aim of piloting a pulsejet powered aeroplane. No, seriously. Legendary German test pilot Hanna Reitsch had flown a modified V1 ‘Doodlebug’ in WW2 to iron out stability problems, but that was it.
The test bed for this work was a scrap go kart which did the job heroically. There's an 'on-board' clip here which shows a start and launch of the jet kart captured on a helmet cam. This particular set up had four high pressure fuel pumps as a throttle. 1 for idle, then the other three were progressively flipped on to increase the fuel flow and hence increase power. The kart launches as I flip the second pump on, then self destructs as I flip the third! So the acceleration you see was on about 35% of max power! Scary stuff.
I eventually came up with a lovely little contraption which took Lockwood’s idea just a step further. The size of engine required would have made it about 6 feet long so I coiled it up like a tuba. There was a slight loss in performance but it worked well.
Immensely proud of this little engine. Packed quite a punch for it's size and was supposed to get me airborne until.....
This would start easily and would run on liquid fuel instead of bulky LPG. Best of all, it was remarkably resilient to self-destructing and could endure long, long runs under power. I approached the technical guys at the British Microlight Aircraft Association with my results and my ideas to fly with it and, to my great surprise, they agreed to let me have a go under special permit conditions.
I was so excited! I was well into the hunt for a cheap single seat deregulated microlight when I suffered appalling burns during a static test run of the engine in the go kart.
The 'Monster' engine fitted to the kart. This was a BEAST and rarely ran for more than a few seconds before blowing up or shaking itself apart. If nothing else it proved there was a definite limit to how big these things can be!
I’d had minor blow ups, it was par for the course, and I had taken to wearing fireproof gloves and an ex navy surplus flash hood. The engine was running tits-out, glowing red hot, when I decided to reach around the firewall and tweak a fuel valve. Without warning, a pipe burst on the fuel heater and sprayed about a litre of kerosene onto the hot engine. I just about got past the ‘sh’ of ‘shit!’ (sorry Linford) when it ignited. The flash vapourised the sleeve of my overalls and left me with 2nd and 3rd degree burns the length of my left arm. My left bicep is permanently scarred. The following blast threw me several metres backwards and left me half deaf for days. It goes without saying that the decision to wear the flash hood that day was one of the best I’ve ever made, although my face was slightly crispy nevertheless.
I dashed off to the water butt that collected the rain off the hangar roof and stuck my arm and face in it for as long as I could. I knew then I was quite badly burnt but thought I’d be okay. If being totally fried wasn’t bad enough, I’d got a flying lesson booked in about 20 mins time and, mid dunk, I noticed the bloke had just arrived in the carpark. I thought about it for a while then heroically headed to the office to put my flying gear on….
That was the worst hour of my life! Absolute agony. I must have been really skint that week or something. It wasn’t until I got home and showed Sue the mess that I realised I was in trouble.
Anyway, it sort of put me off the idea of taking to the skies in an aircraft powered by one of those temperamental pulsejets. Shame really….
One of the best things to come out of the whole pulsejet adventure was this FABULOUS BIT OF FOOTAGE. We had a party at the airfield one night and, in my drunken stupor, got bullied into tearing up and down the runway a few times. Spectacular!!
Here's one of me and Tony not getting fried for a change. This was taken during the Beccles Straw Race 2004 - it's basically a drunken race around all the pubs in town carrying a straw bale for charity! Okay, we didn't win but we definitely had the grooviest way of transporting our straw bale...
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