Republic JB2 or V-1 copy

Quite some time ago (2013!) I built a Depron JB2 with a 55mm EDF.

It has been flown spasmodically ever since and with the current fine weather I decided to fly it again but was foiled by a catalogue of faults.
1. Somewhere along the line I had deleted the model on my DX6i! No problem it would just a new model creating and rebinding.
2. This was one of my first 2.4 planes so I had not accounted for the possibility of rebinding so the rx was completely built in!
3. Fortunately I did a build blog on another site so I have full set of build pictures which allowed me to work out exactly where the rx was and the best way to approach it with the minimum of damage to its stressed skin structure.
4. Managed to insert a bind plug with considerable difficulty and rebind only to discover the elevator servo only buzzed and did not function.
5. For CofG reasons the 5 g elevator servo is positioned right in the nose with 1 m long pull/pull cables so more pictures needed to work out how to get at it and another substantial cut out made to extract and replace it.
6. Then I found the rx would not keep its bind! To actually get the rx out and replaced needed a rather bigger access hole.

Hopefully I will be able to get it all finished before the weather breaks!

Well that did not go well!

No problem it climbed away from the hand launch as normal then put it into a gentle turn (aileron as it is bank and yank) but it then just kept on turning - no ailerons. A snap of full up elevator caused a stall which almost levelled the wings but then the previous turn resumed (the ailerons still set with bank?) with ever increasing bank (no dihedral). I nearly got the wings level reasonably close to the ground but the 'landing' was still at flying speed with left wing low which snapped the wing spar where it passes through the fuselage. It made quite a crack!
Puzzled at the loss of elevator I left the plane exactly were it was on the ground and walked back to where I had been standing waggling the sticks as I went - everything worked fine.
I can only assume there had been a loose connection which the impact cured!

Some more repairs!

What change in the weather so I could happily spend a few hours putting the JB2 (V-1) back together without worrying about missing flying weather.

In fact looking at the weather forecast by the time it can be flown again the glue and paint will have has plenty of time to dry!

This story was never quite finished.
It was repaired but crashed again on 26 Aug 2019!

This time the damage was rather more severe as not only was the RH wing ripped clean off but both the nose and tail end were also severely disrupted. Not surprising following a proper cartwheel!
I had 'retired' the wreck to the loft but with the lock down still in place I will restore it as it should not require too much of my limited supply of 3 mm Depron to do.

This was one of my early Depron builds (Feb 2013) and my first true EDF so I have a few construction improvements in mind, like build a straight through 'one piece' wing, proper cooling for the ESC and a hatch to get at the rx to allow a rebind!
I suspect it is using a DSM2 rx so I will invest in a diversity antenna DSMX one or maybe even a gyro version.

love to see it fly again Simon, I've still got in mind a free flight version, I did take a look at the motors Doctor Rocket mentioned ( remember him?....Another very talented chap frightened off imho) but they worked out at around £10 a pop..

Just a small up date.
It did indeed have an Orange DSM2 single antenna rx.

Although they work ok in a 'quiet' radio environment they are considered park fly only by most. To make matters worse these early R610 models are noted for taking a second or two to reboot on loss of signal which usually means a crash. This 'feature' probably more than anything else gave Orange a poor reputation in the beginning.

Salvaging it from the V-1 means I now have four of them in my spares draw.

I did not actually buy them all in fact when I bought my second hand DX6i the seller gave me 3 of them for free!

First job is to repair the wing or rather completely detach them from the fuselage.

The wing has a substantial balsa/Depron/balsa box spar. I was remarkably conscientious and tapered it to a point at the wing tip.

The fuselage was built with a big hollow box spar across the fuselage and each wing was simply plugged into it and glued in.
Although structurally stiff and plenty strong enough for any flight load it did mean the wing was significantly weaker to any for and aft load, like touching and wing tip on landing! To make matters worse the resulting break would be right at the wing root and almost impossible to repair.

On this rebuild the wing will be in one continuous piece tip to tip and simply fed through the fuselage then glued in place.
The intention is that under a severe wing tip load the wing will, as a single piece, simply 'break open' an area of the fuselage. It will look bad but is actually simpler to repair.

A new continuous box spar with ribs joins the left and right wing panels.

The skin added top and bottom to form an 'plank'.

The aileron servos have been checked too.
The fuselage will need rather more extensive repairs.

Made a slow start on the fuselage today.
The initial stage was to secure the 'strained' joints on the pulse jet mountings. In fact it proved to require no more than inserting a hard setting glue all along each joint and leaving it to set.
Later the nose was cut open to identify the scope of the internal damage which as expected was fairly extensive.

The ESC was fully 'released' to enable a ribbed heat sink to be attached. It used to get uncomfortably hot.
Many of the joints in the battery compartment had failed and the bulkhead prior to the nose cone was severely disrupted so was removed.

The opportunity was taken to test both the fan and the elevator servo.
Hopefully no more skin will need to be cut away so reinstatement of the nose can start.

By far the trickiest operation will be preparing the fuselage to install the wing which is why I have left it to last.

Very gradually putting bits back on the nose. The ESC with its new heat sink was a significant step.

Some planking and the replacement nose cone underway.

The pale blue blob just below the ESC heat sink is the elevator servo.
The elevator it moves is no less than 1020 mm (47") down the other end of the fuselage.

Still quite a way to go.

Ooops! I obviously had a spelling error. Thanks Klippy.

Not much progress as I set about installing the rx yesterday then had second thoughts so today did it all again.
This time the 'diversity' Rx is just under the skin such that it will be possible to lift it out along with sufficient spare servo wires that it does not have to be disconnected.

This however leads to a 'chicken & egg' situation that requires the wing to be installed and the aileron servo wires run inside the fuselage to the Rx before its installation can be finished.
So the next job is to print out a 'rib' that exactly matches the outer surface of the wing.

This will indicate exactly where the fuselage formers have to be cut to allow the wing to be slid through.

It could all go horribly wrong.

Struggled all day but at last the wing is in position.

Much to my relief it looks to be all square to the fuselage and parallel with the tail plane.
It is glued to the fuselage formers so will have to sit like that until the glue sets then the remedial planking can start.
There is quite a bit to do in some places.

In theory the wing has gone back where it was and at the same incidence, +1 degree, and the battery will be the same so.......
We shall see.

looking good Simon, can't wait to see it fly! Been looking for a plan for one with no luck however the vintage model company do a kit