A Depron Harrier

The four nozzle duct is horribly complicated! :ohmy: :ohmy:
The inlet side for the front set of nozzles.

The circular duct is divided into quarters. Cascades in the L&R quadrants direct the flow outwards to further cascades directing it rearward.

The top and bottom quadrants will be ducted back to the rear set of cascades and nozzles.
The front nozzles in position on the fan.

So far it weighs 4g.

It will be miracle if it ever works well enough to fly.

To combine the top and bottom quadrants into a single duct to feed the rear nozzles requires some even more convoluted ducting. :woohoo:

It is symmetrical and leads to a fine edge where the two streams combine.

Of course absolutely none of this will be visible when it is completed so these pics are for my benefit as much as any ones!

Well it may not be a Depron Harrier yet but it could be a Depron Pegasus!

Not yet tested (the glue is not yet hard)

It weighs 2.71oz (76g) with the EDF

Hopefully it will generate as much thrust as the two nozzle duct. If it does then I will need to consider what sort of Harrier-esk airframe to mount it in.
To get the CofG anything like right I suspect it will have to use a pair of 800mAh 3s batteries mounted either side in between the front and rear nozzles.

Late update
It actually produces more thrust than the twin nozzle 11.9 oz instead of 9.1 - so some sort of airframe is definitely required!

As I put previously - too much back-pressure stalling the fan blades?

Eric
I don't think there is a stalling problem just the drag effects from dividing the flow into 4 small ducts and then diverting it through 180 degrees!

My V-1 uses exactly the same EDF mounted on the front of a long parallel duct. It gives 12oz static thrust suggesting the 4 nozzle is about as efficient.
One advantage of the 'Pegasus' layout is the thrust when in the plane will be the same as that generated on the test stand as all the ducting is already in place.

Where the 4 nozzle may not work so well is at speed. To find this out is one of the reasons I want to put the test duct in a plane.
We shall see.

When I looked at a 3 view of the Harrier scaled to the size of the test duct it comes out very small, just 17" span! :woohoo:
At this stage it only needs to be 'Harrier like' rather than true scale so I simply stretched the wing span a bit.

It will have a 27" span and be 30" long.
The fuselage will a 'simple to build' hexagonal cross section but with a more or less scale profile.

I need some more Deporn!

ps
I know I only stretched the wings in the plan view!

Hmmm maybe i would like some DEPORN as well :lol: :lol: :lol:

Wow Weeeeeee

We are turning into a porn site :woohoo: :woohoo: :evil: :evil: [badass]

Garry

Where's the pictures? [badass] [badass] [badass]

Pictures?
At the moment its still just the 3 view. I haven't built any of it yet!

17" - Don't blink, or it will be O.O.S. ! :woohoo:

My micro-mossie is 20" span!

Er...that's why I stretched the wings to 27"!

The start of the hollow 'profile' fuselage.

With 2mm Depron skins it will be 15mm thick. The cut out matches the four nozzle EDF unit which will be simply glued in.

Crude and simple the target it to keep the all up weight as close as possible to the 11.9oz thrust.

The basic profile fuselage weighs 0.76oz
The 4 nozzle EDF unit glued in place.

The fuselage has been brought down to fine edge just ahead to the fan inlet.

As I feared the only place for the battery to maintain the CofG will be between the front and rear ducts either side in a 'saddle' arrangement using 2x850mAh 3s 30C.
The elevator servo and radio will part submerged within the profile fuselage.
With the non scale big span 27" wing it should have a reasonably low wing loading.

A start on the wings. A very typical 'Hawker' outline (almost identical to the Hunter) which betrays the Harriers rather 'old' basic design.
No spar again, just Depron with shear webs!

Very thin so even with the micro servo lying on its side it protrudes slightly from the under surface.

I have to admit a slight non scale feature - apart from the greater wing span! The full size GR3 has 'inset' ailerons to allow the wing tip wheels to retract backwards. For simplicity my ailerons go right out to the tip.
The hollow wing means the aileron servos can be installed after both skins go on as there is plenty of room to feed the servo wire down the wing between the shear webs..

The all moving tailplane is next.

This amused me.
The HK parcel that contained the two LiPos for the Harrier.
Despite what it says on the 'crushed' label it was delivered anyway!