A Depron Harrier

Ah - but - if your postie is like mine, he is Lithuanian, or Latvian, or something, and no spikka Angleesh! :evil:

The pair of 850mAh 3s in place between the nozzles.

It makes a very compact installation. I have still got to figure out the best place for the ESC.
The all moving anhedral tail plane.

It uses a glass fibre tube pivot running in plastic bearings. I suspect it will need to be mass balanced to prevent flutter.
As the elevator servo can be positioned almost anywhere along the fuselage it final position will be determined to achieve the desired CofG.
So far it looks like the Harrier should be no more than 13oz all up.

If you keep the AMT pivot point well forward, somewhere around 1/3 root chord, and the control horn well aft, or on a long arm below the pivot, there won't be any flutter to worry about until you get close to Mach 1. Just make sure you use a stiff linkage with no slop.The hardest part of setting up an AMT is getting the neutral pitch angle right. You don't need much movement, either, compared with an elevator, so a small error is a huge pitch mis-trim! (Been there!)

It is the very sensitivity of the movement of the AMT that gives me cause for concern about flutter particularly if for CofG reasons the elevator servo ends up near the nose! :woohoo:
I don't think mass balancing will be too much of an issue as it will only require 1.6g to put its CofG on the pivot line.

As Eric suggests it is probably completely unnecessary but each tailplane now has 0.8g leading edge mass balance.

First trial assembly.

Still a bit to go though.

The nozzles themselves need to be faired in, particularly to the rear as the front exhaust air stream runs close to the rear one.

The bluff front is also faired in to reduce drag.

I need the 30A ESC next to work out exactly where to put it and how to run the motor and battery wires. Not quite a easy as it sounds as they obviously must not get in the way of the exhaust air streams!

At long last the ESC arrived from China so the electrics can start in earnest.
This is a very (and it is very!) compact installation so I wanted everything to hand so I could work out exactly how it could all fit.
The saddle batteries each with their own connector.

They feed down to the ESC mounted underneath such that Its heat sink is on the outside.

Which in turn feeds forward to the EDF.
All the wires are cut and soldered exactly to length.
The radio will be positioned on the side of the fuselage just behind the rear duct to keep it as far away from the motor/ESC as possible.
Nearly there.

My profile 'big wing' Depron Harrier is at last complete.



It weighs 11.6oz (329g) all up.
With 11.9oz measured thrust it should be able to fly but I fear it may be quite a handful!

A video of the maiden Simon please, i think a 45deg launch will be in order to give yourself room to get it stable
Good luck

With a better than 1 - 1 power to weight ratio, it should go vertically up, indefinitely! :woohoo:

Should maiden tomorrow. Warm sunny and just 2mph wind (it says!).

Weather as promised so here is the maiden video.
Not a lot to see as it is relatively small, white and I kept it reasonably high (actually no more than 100'!) for obvious reasons.

As expected plenty of thrust and the anhedral has definitely worked - it has absolutely no roll stability! :woohoo:
The fan windmills freely when gliding.
Aerobatics next.

Well done Simon it flew well ,

Very nice indeed,

Now let's see it hover. [badass]

Hover? A bit to go before that!

The next step is to build the same sort of nozzle arrangement but using a 70mm fan as it will be more efficient in producing thrust /watt.
In addition the intention would be to create round outer nozzles as this would be a prerequisite if any sort of thrust vectoring was ever to be attempted.

If it can be built, it would logical to encase this "Pegasus" in a true scale Harrier fuselage.
The thrust to weight achieved at this stage would determine if there was any point in going further.