Portable 70cm Yagi

I had a go at building a small (apx 1mt long) 6 element yagi with a folded dipole. It is designed with a handle for hand held operation in Radio Direction Finding activities and to be mounted to a small mast I have that extends to about 2.5mt high for QRP operation.

Here is a shot of the mast and aerial collapsed to fit in the trailer I am building to go behind my motorbike.
 A shot of it set up on the mast which is freestanding
A close up of the yagi atop the mast

Motorjet to startTurbojet

G’day All,
it’s been a while but I’m back!
(too many Projects, too little money)

Iv’e been working on a Starter Motor for the Turbo Jet project,
I don’t know weather you can make it out from the pix but it’s a Cox .049 ci
with a puta fan blade attached!
(yes Brad it IS the same motor I used on the model boats we made as teenagers!)

Appearntly people tried using puta fans as ducted fans in the early days but,
found them to be useless cos the crappy plastics they were made of used to
fly apart when exposed to 22,000 + rpm
(I wonder why?)

But thankfully puta fans now are made out of tough ABS plastic,
which should be up to the task!
Some of the better quality fans are actually balanced!
(you can see the dremel marks on some the back of the blades!)

Cox went out of buisness in Feb 2009 but Iv’e found a shop
in Canada that has a warehouse full of motors and parts!
(and he does bulk lots too! I bought 6 piston/conrod/cylnder assys for
less than 30 bucks au, including postage!)

You can still get the parts to make a replica “Black Widdow Venom”
(the originals were only a run of a 1000 and are very rare!)
BTW, FYI, the “Black Widdow Venom’s” were the motors that could pull
22,000 revs!

I have yet to fabricate a bracket to mount the
motor in the “Duct” but as you can see it basicaly
fell together, just drill a few holes in some Stainless Steel tube and Vioal!
A home brew Ducted Fan,
the stainless came from the inside of a “Thermal Cup”
and is quite lightweight and a perfect fit to the Turbo Inlet.
(just dumb luck!)

The motor in the pix is also rare for other reasons,
it is a single transfer port bore which were discontinued early on cos
they only pulled a measly 10,000 to 12,000 to revs!
The more common one comes
with 2 transfer ports and “Slit Exhausts” they pulled from 15,000 to
17,000 revs!
And the Venom’s piston was lightened, polished crankshaft, they had
extra ports and had higher compression
they were capable of 22,000 revs

The Idea is use a drill to start the Cox motor then plug the Cox into
the turbo’s inlet to start the Turbo Jet!
Cool huh?

Ducted Fans actually qualify as a Jet by themself and are also known as Cold Jet’s ,
Motor Jets or (my personal favorite) Piston Jets!

cheers, Mick. ‘-))

if you can’t make me a better Boy,
don’t worry about it,
I’m having a great time as it is!

Air Wasp

Earth shattering News dept.

I am now the proud Owner/Builder of a working Pulse Jet!

The Bush Pig was a bit of a Dud,
(Mark reckons it’s a win coz we got it to run, I say it’s a dud coz it wouldn’t sustain it self without the start air!)

But it was a learning experience nonetheless.

The trick is to make a Pulse Jet not a Ramjet!

Anyway, I was a bit bummed so, I went online and found a plan, (of an actual working one, [I checked on Utube first!]) of a Chinese Acoustic Folded Wave Engine!

I had to change it slightly, for ease of construction.
( you know me, I had to give it the Mick twist!)
If you look closely at the plan vs, Me you’ll see my combustion chamber is stepped and the plan calls for a proper concentric cone, as I said earlier it was an ease of construction thing!

I did find out however. that the most important thing is, the centre line of the inlet tube must be aimed at the seam between the domed front and the c/chamber at the bottom!
(don’t ask!, suffice to say it put me back a day on the build!)

I must say starting one of these Bastards is actually not quite rocket science but, it seemed like it, till you work out the art to it!

But the upshot is,

It runs!

Most Importantly,

By itself!

Warning! Wear hearing protection!

Wow the noise Indescribable!!!!!!
No matter how hard you poke your fingers into your ears, it’s still uncomfortable!
( the noise that is)
(pushing in your fingers too hard is no picnic either!)

And I wasn’t prepared for this, the Vibration!
It’s incredible, you can actually feel it in the ground coming up through your Feet!

We did take a Video but it has to be edited, so you’ll have to wait for my next post!

The pix will be better tomorrow (it’ll be daylight!)
I have a full tank of L.P.G. and I intend to use it!

That’s all for this post,
see Y’all soon,
cheers, Mick. ;-))