I've fitted a PJ8C into a Chinese ARF Bobcat 52 and started the test-flights.
Because the engine is mounted part-way inside the fuselage, I had to add some
ducts so that it can breathe. Originally I tried to use some low-drag NACA
ducts but they didn't supply enough air so I added scoops, which improved things
but the engine is still starving for air.
The next step is some internal ducting to direct the incoming air towards the engine's
intake.
But enjoy the video of progress to date:
How fast?
Here's the latest video of my PJ8C-powered Long-EZ ARF flying.
I swapped out the original first-prototype for the second prototype on which
all production engines are based. This is now one seriously-fast RC model.
There are many turbine-powered models costing thousands of dollars which can't
keep up with this low-cost jet-powered ARF and instead of using expensive,
harder to get jet-fuel mixed expensive turbine oil, the PJ8C runs on regular
gasoline from the pump at your local garage.
See how the PJ8C is made
Quite a few folks have asked to see how the PJ8C is made so I've created
a page with a few pictures and a brief description of how I build these engines.
If you're curious, check out the How the PJ8C is made page.
How do pulsejets work?
Although I've written a lot about pulsejet engines, one of the questions I
still get asked most often is "how do they work". To answer this I've
created the following YouTube video. I hope it will explain all.
There's never been a cheaper way to get into jet-powered RC model flying.
Ceramic coating and pulsejets
One of the big problems with pulsejet engines is that they run very, very hot -- soemthing
that often limits their application and reduces their operation life.
To help reduce this problem, I'm now using a ceramic coating (which the manufacturer
claims is also used by NASA) on the inside of
my engines which protects the metal from exposure to hot combustion gases
and also provides a measure of insulation -- effectively improving efficiency
and reducing external operating temperatures.
More to follow on this...
The new PJ8 takes to the air (update)
An updated version of my PJ8 design has been test-flown in a cheap Chinese
Long-EZ ARF. (and a special version for the BobCat 50 ARF should be ready
in a week or two).
The fuel-bubble issues have been sorted now and I have been able to enjoy
some much longer flights with the PJ8/Long-EZ combination.
As you can see in the new video (below), the PJ8 is a good match for the Long-EZ
airframe. The reed valve that has now done quite a few flights and much static
ground-running (while fixing up the fuel system) finally expired on this flight -
you can year it starting to sound a bit odd near the end of the flight before
I cut the engine.
Because the Long-EZ doesn't have a tail, it was very easy to modify for pulsejet
power.
More video of the Long-EZ will be posted soon and the updated plans will be
added to my Pulsejet Book.
At last, ECU for pulsejets
An interesting project I've been working recently is an Engine Control Unit
for pulsejet engines.
Lots of folks have talked about using electronics to provide better control
of pulsejet engines but, to the best of my knowledge, nobody has actually done
so to date, or at least not until now.
The circuit you see in this picture is a rough and ready (but fully functional)
prototype of my pulsejet ECU system.
Although it looks a bit like a bird's-nest of wires and components, this ECU
does some very clever stuff. For example, it actually listens to each combustion
cycle using a transducer. That information (along with other data such
as temperature, mass-flow and thrust) is constantly monitored and used to
fine-tune the engine's operation and ensure maximum performance is achieved
at all points on the power-curve.
The ECU also supports fully automated start/restart and shutdown for engines using gas
and/or liquid fuel.
Right now I'm designing the final circuit board which will see all that mess
condensed down to a unit about the size of a credit-card.
Stay tuned for more information and some video of the ECU in action.
I'm back!
After a long time away from my pulsejet projects I'm back!
This site will be getting a major facelift pretty soon and I'll be showing you
some of the cool stuff I've been working on in the pulsejet area.
I'm currently preparing a new XJet prototype that will be shipped off to a university
for testing and validation of the performance, this being the final step before
commercial production.
And I've also been very busy writing my book which is chock-full of stuff
that any tech-head will find both entertaining and interesting.
If you missed it, I see that the epsiode of ScrapHeap Challenge in which I
appeared as an "expert" and directed a team of Navy engineers in their
task of building and racing a pulse-jet powered vehicle has been uploaded
to YouTube. Links to these videos are on my
Scrapheap Challenge page.
The biggest, meanest pulsejet dragster ever! UPDATE: we've had our first short runs in the dragster and it is, in a word,
"frightening"!
And here, as promised, are a few pictures of the tentative first few runs.
The power to weight ratio is extremely good, producing some really astounding
acceleration, and the noise is astonishing -- especially when the engines
lose synchronization and a beat-frequency can clearly be heard modulating
the level of sound and vibration.
One thing that immediately became apparent however, is that if the engines do
lose synchronization, there's a definite tendency for the exhaust of one to be
ingested by the other, resulting in a premature flame-out.
This problem will be significantly reduced when the augmentors are added but
in the meantime, a simple dividing plate between the two intake pipes seems
to have dramatically reduced the magnitude of the problem -- albeit while
making the engines less likely to sync-up in the first place.
It's been quite a while since I updated this website but I've been very busy
in the workshop. Here's a picture of what I've currently got under construction:
This monster is powered by two enhanced Lockwood valveless pulsejets which
have been tested to produce 150lbs of thrust each in an unaugmented configuration
when run on propane.
Early tests on Jet A1 indicate that this thrust can be lifted to around 180lbs
each and, with the addition of an augmentor, a figure of around 220lbs of static
thrust per engine should be possible -- for a total of 440lbs.
The entire vehicle currently weighs in at under 180lbs so I'm expecting some
pretty impressive acceleration and speed.
I'll be posting more pictures in the next week or so.
Note that this engine design has been licensed to a New Zealand company
(SimpleJets) who have
already started manufacturing.
TV Crews All Over The Place
Over the past six weeks or so I've had TV crews here on a fairly regular basis.
They've been filming a couple of items on me and my jet engine activities. Unfortunately,
this footage is unlikely to be seen outside of New Zealand but we did some really
cool night-runs with the JetKart that looked very impressive.
This shot in particular shows how a vortex forms in the exhaust of the pulsejet
during the exhaust phase.
I'll post some more pictures from these night-shoots in a week or so when I've
had a chance to dump it onto my computer.
Kids, do not try this at home -- I am just crazy
To see what's new on this site,
check out the Master Index page each time you visit.
If you're looking to build a jet-powered gokart or small vehicle and you want
the help of the guys who featured in the JetRacers edition of Scrapheap Challenge
then you really ought to get The Expert's CD.
This is a disk chock-full of plans, step-by-step instructions, videos
and a wealth of other information that contains all the information you'll ever
need to build your own pulsejet or turbo-jet powered vehicle. You'll also
find out exactly what goes on behind the secenes of this great TV series.
Pulsejet with Afterburner??
A lot of people have asked me whether you can fit an afterburner to a pulsejet
and I've always told them "no, it won't work." However, I've never been one
to be put off by being told something won't work -- so I tried it.
Read more about it.
Guess Who Helped On Junkyard Wars?
Yes, although you didn't see my ugly face this time, I was there, behind the scenes
working a a technical consultant during the filming of
the DragBoats episode
of Junkyard Wars. I was the one who designed the big pulsejet that featured
in that episode, you can find out a little more here.
Guess Who Was On Scrapheap Challenge?
Yes, I was recruited by the folks at RDF to act as an "expert" in the
recently screened jet-cars episode of the very popular
Scrapheap Challenge (aka Junkyard Wars)
series.
Fellow "expert" Nick Haddock and I have produced a CDROM that contains
a whole heap of information about our experiences on the show, along with
lots of pictures, videos and plans that you can use to build your own
jet-powered karts using either a pulsejet or turbojet.
How Fast Does The Jet Kart Go?
Up until now I've just been guessing at the top speed of my jet-kart
but seat-of-the-pants estimates can be rather unreliable so I fitted
a GPS and took it out to a nice, long, straight piece of tarmac.
New Pictures of my BIG Lockwood pulsejet
Check out new pictures of the biggest Lockwood pulsejet I've ever built
and see if you can work out what I'll be using it for. The details
are at the bottom of this page.
Coming Soon -- Jet-kart-Cam
As soon as the weather clears I'll be recording some onboard footage of
the jet-kart in action and the onboard GPS will tell me exactly how fast
it's going.
It'll be the next best thing to actually being in the driver's seat so
find out more here.
Rare V1 Videos Added
I've just added a couple of short clips of the V1 flying
bomb to the Argus V1 page.
The second one is very interesting as it shows a V1 with
what appears to be flares or rockets on its wingtips.
Some New Video Footage
In response to many requests, I've edited a couple of small video
clips of the Jet-kart in action and put them up on
this page.
A Wooden Pulsejet?
Not really -- but here's some background on
a simple 2D flow-modeling rig
I've built to test some of my ideas. I've used it to verify
the ideas behind my proposed Coanda-effect valveless intake system
Latest Addition: A New Valveless Intake System
Here's an idea I've been musing with which has application
to the intake system of valveless pulsejet designs. I've posted
a new page that explains
how the Coanda effect might be used in the
design of such engines.
Master Site Index Now Online
It's come to my attention that there are parts of this site that
are not easy to find. So that you can check out every little nook
and cranny, I've added a
Master Index that includes direct links
to every page. Check it out -- you never know what you might have
otherwise missed!
Oh, and there's also a list of
Frequently Asked Questions that is worth checking
out if you've got any queries about pulsejet engines and their construction.
New Valve-head Design for Traditional Pulsejets
While X-jet development remains stalled due to a lack of funding,
I've been applying my mind to the improvement of traditional pulsejet
engines and have just posted a new page (NOW WITH PICTURES)
that details another innovation.
This new valve-head and injection system
has proven to be a very successful way of increasing the power, efficiency
and valve-life of traditional petal-valve pulsejet designs as well as allowing
the direct-injection of liquid fuels without the need for an expensive
high-pressure pump.
As with the Blast Ring (which this new system effectively replaces), I'm
placing this new design into the public domain so that others can use it
freely. It is simple enough that it could be fitted to almost any existing
petal-valved pulsejet, including engines such as the Dynajet, Tiger Jet
and others.
Feel free to use this design in your own engines, all I ask is a little
attribution where relevant.
23 June: You just have to see the latest Jet Kart picture I found!
The X-Jet To Go GPL?
Should I place the X-Jet and all the R&D work done on it to date into the public domain?
Visitors since 6 April 2002
The Low Cost Cruise Missile
Want to build your own cruise missile? It's easier and cheaper than you'd think.
Pictures of the Jet-kart in action
I'm now back in the workshop full time and catching up on all the work that
accumulated. I've also added some pictures of the jetkart in action:
This logo and link have been seen almost 150,000 times since September 2001 --
and all it cost Amsoil was just one gallon of their oil. If you'd like to sponsor
some of the projects documented on this site and get a similar level of promotion
right here then click here for more info.
IT RUNS! -- check out the pictures and video
of my Gas Turbine Engine which I ran for the first
time on 9 April 2000.
Some Background
When I first started tinkering with pulsejet engine technology in 1999,
I realized that there was huge potential for improving these devices.
Although deceptively simple in construction, their design had changed
little in the 55 years since the end of WW2, when they were rapidly
replaced by the now common turbojet.
The opportunity to apply 21st century materials and knowledge to the
task of improving a design still mired in the 1950's was too great
to resist -- so I set about developing a range of engines, each
incremental better than the last.
In early 2001 I took the results of over a year's experimentation
and designed the radically new X-Jet engine which
now surpasses traditional pulsejet engines in terms of performance,
efficiency and reliability by a huge amount.
The improvements are, in fact, so significant that they have once again
made the pulsejet a definite contender for specific low-end applications
such as recreational vehicles (including microlight and homebuilt aircraft),
military drones, etc.
Thanks to the X-Jet design, it is now possible to sell a reliable
jet engine producing over 55Kgs (150lbs) of thrust and weighing under
6.5KG (15 lbs) for less than US$1,000, more than 20 times cheaper
than the equivalent turbojet.
As a result of the information published on this website, I have already
received a significant level of interest from people wanting to buy
one (or in some cases more) engines based on the X-Jet design, however
my resources are limited and at this stage I will continue to work
on further improving and refining the design rather than diverting my
attentions to manufacturing activities.
This development is continuing thanks in part to a technology grant
from the New Zealand government -- but additional investment capital will
be required to commercialize the engine for licensing and manufacture to
a global market.
Inquiries are welcomed from investors who may wish to participate in
commercializing this design and companies which may wish to manufacture
the engine in various sizes under license.
If you're looking to build a jet-powered gokart or small vehicle and you want
the help of the guys who featured in the JetRacers edition of Scrapheap Challenge
then you really ought to get The Expert's CD.
A lot of people have asked me whether you can fit an afterburner to a pulsejet
and I've always told them "no, it won't work." However, I've never been one
to be put off by being told something won't work -- so I tried it.
Read more about it.
How Fast Does The Jet Kart Go?
While X-jet development remains stalled due to a lack of funding,
I've been applying my mind to the improvement of traditional pulsejet
engines and have just posted a new page (NOW WITH PICTURES)
that details another innovation.
