An EDF Fieseler Fi103 - the V1 - in Depron!

[quorneng]

The rear two sections of the fuselage joined.

At least they seem to match reasonably well!
The wings plug into a balsa/Depron/balsa box spar that spans the fuselage.

The wing has wide but thin (1mm) balsa spars tapering towards the tip with 3mm Depron webs between the ribs.

At 40" span the V-1 is small enough to be transported complete so the wings will ultimately be glued in for maximum stiffness and strength.
With the 2mm Depron bottom skin added the 3.7g aileron servo is glued in.

The completed wing. It has a completely symmetrical section.

The aileron is top tape hinged with a short servo link underneath.

[JetPlaneFlyer]

Great project! i always meant to have a go at a V1 some day, even started to draw up a plan but it never got far.

It always amazed me how they managed to keep the real one stable and steer it with rudder only when it had no dihedral at all. I figured it out in the end; it's to do with the pylon mounted motor, but it will only work when the motor is running and making thrust, not an issue as the V1 didn't have to have control to land

[quorneng]

With the fin added the pulse jet can be fixed on.
It starting to actually look like a V-1!

The nose section is built in the same way as the others.

The former at the join line is a dummy used only during the build.

It is completely removed once the planking is complete.

The corresponding former on the centre section has a 3mm sq Depron flange to locate the nose skin accurately and to provide a bit more glue area.

The fuselage has to be complete before I can judge where to put the battery. ESC and radio to arrive at an appropriate CofG.

[quorneng]

Before the nose is glued on all the wiring in the fuselage have to be secure.

They are all long enough to go right to the nose if necessary.
The nose on thus completing the basic airframe.

At this point I realised that there was no way I could achieve even a 30% chord CofG without a battery of at least twice the weight!
The heavy item in the rear are the EDF and the tail mounted elevator servo.
Obviously I could do nothing about the EDF but the 5g servo is a long way back. A quick check of the moments suggested nearly 60% of the weight of the intended battery in the nose was required to counter balance it.
The solution would be to extract the servo and mount it in the nose with a cable pull/pull system.

The elevator itself had to be removed to fit a double sided horn.
The nose was always going to be cut open to mount the battery box, ESC and radio but now had to include a servo as well.

So far so good but although the fuselage is basically empty, running and tensioning the elevator cables is not going to be easy.

[quorneng]

The Depron battery box.

The elevator servo goes underneath with the radio in its own box on the left and the ESC on the right.

The ESC has an external finned heat sink.

The nose cut out can now be glued back in pace leaving just a small aperture just big enough to slide the 1800mAh 3s in.

Finished off with a hatch that also locates and secures the battery.

It now weighs 20 oz and has a CofG at 27% wing chord.
Not the 17oz that was my target but quite a bit of the extra is due to bigger, heavier 'high C' battery.

Now for the maiden.

[quorneng]

It flies, and surprisingly well.
This is the video of its second flight. It had to be edited as it simply did not show on the video some of the time but does include a most unV-1like loop and a roll.
https://vimeo.com/62004112
No speed merchant although it does seem to retain roll authority at remarkably low speed.
The only real problem is the ESC overheats and reduces power after a minute or so at full power. Not that is too much of a problem as it flies well on a much reduced throttle.
It is now painted as a 1948 USAF JB2 LOON which was conveniently white overall except for the pulse jet.

'Star and Bars' insignia will be added to the wings and tail.

[DEG]

Very nice build and flying. Gonna scare a lot of the older folks into thinking they're being attacked again.

Don

[pmullen503]

Well done! It really does just float in for landing. What is the wing loading?

[quorneng]

If you discount the fuselage it has a wing loading of 11oz/sqft but I suspect the substantial fuselage area adds quite a bit of lift at high angles of attack.

The reason I picked a JB2 colour scheme was simply to make it easier to see and to save weight. The original V-1 mottled green top surface and pale blue under was of course designed as camouflage.

A still from a video on a sunny day does rather show how 'translucent' the wings are.

[quorneng]

After the last nose damage I decided to improve the ESC cooling by removing the shrink wrap and mounting the heat sink flush with the skin surface.

A duct feeds air across the inner ESC surface as well.

The inner duct exits into the fuselage and exhausts through a 'finger hole' on the underside.

This reinforced hole allows my index finger to give a positive shove at the launch without relying on excessive hand grip pressure.
An edited video of today's flight in rather windy conditions but there was no drama at the launch.
https://vimeo.com/62990598
I am still amazed at how well it glides.
The significant wind shear close to the ground resulted in a rather untidy but otherwise slow safe touch down.

[pattern14]

Just got back to this thread after some time away. Well done; she looks great. Flies better than mine did too....