Douglas F4D Skyray

This may be a blind alley, but try changing the length of the wires from the lipo to the speedo, and the speedo to the motor, by a couple of cm.
You may have just dropped onto a resonant frequency length which is 'confusing' the esc.

A change in wire length might do it but to be sure I have changed the speedo which has required all the joints to be re soldered and the wire length are slightly different too.
I have also started repairing the fuselage. It is now down to four big bits which all fit together, more or less!


Changing the prop is still beyond me though!

Slowly putting it back together.

I finally solved how to change the prop.
First it needed a long 8mm socket extension. Long enough, actually a carbon tube, to reach the prop nut from an inlet!

Once undone the 4 blade prop just fitted through the RH inlet but not the LH one. :huh:
The next problem was how to place the prop on the motor shaft. Solved by undoing the motor bolts and manipulating it through 90 degrees so the 3 blade prop could be fed through the exhaust & coaxed onto the shaft. The motor was carefully turned back to face forward.
The prop nut was glued into the socket and the extension fed down through the inlet. With the motor held directly facing the inlet the prop nut was screwed down. The motor was then bolted back in place on its mount.
Unfortunately this was not quite the end as the whole process had to be repeated to extract the 3 blade as the tips had to sanded down a touch. It was about 1 mm bigger diameter than the 4 blade one and that was already a very close fit in the duct! :woohoo:
The three blade is a 3045. Just showing off the zoom on my new camera. Those are 2 mm raised numbers.

As hoped it absorbs a full 10A on the 1000mAh 4s, which is twice that of the 3035 4 blade, showing 154W and a lot more thrust.
Now to fill and finish off the paintwork - again ready for the next crash!

Dead calm this afternoon so another Skyray attempt.
It now has plenty of power never actually used full power. Flew around for 2 minutes, very twitchy. I can live with the sensitive roll but the pitch was virtually unmanageable, particularly with any 'down'.
HK TX6i has adjustable servo end limits so I limited the down travel but left full up.
Now quite flyable just needed to find the trim sweet spot but then no power, no control. It was gliding quite nicely so I had time to really determine there was nothing. :woohoo:
It flew out of sight into a substantial clump of bushes making a substantial bang.
Easy to find but of course the undergrowth was all brambles. Actually it was the brambles that stopped it rather than anything stouter so the damage was not too serious, new windscreen and canopy, but with many surface 'dings' of the foam.

There are two phone masts on the edge of the field and it was flying directly towards one, about 50' distant, and away from me at about 150'. The rx has diversity antenna but they are right in the nose, so the motor, its wires, the battery and ESC were all in line with the tx.
Well that's my theory.
Should be fixed by tomorrow but there is significant rain forecast for the NW.

C of G a shade too far back? (Wings/Deltas are very critical)
Your closing comment of the previous post was sadly prophetic!

After flying into the dreaded willow plantation at the DVMFC on the 27th.

It is now structurally back together.

But the major impact on the left wing ripped off the LH elevon and in so doing stripped a tooth in the servo so it will have to be cut out and replaced.
The biggest worry is there might not be enough 'free' servo wire to make a solder joint and to heat shrink.

As the Skyray is now getting a bit dog eared I am seriously thinking about building another blown up by 1.358 to give a 36" span. This would then be at the same scale as the XPS Hawker Hunter and others. It would also allow true a true scale inlet and exhaust to be used.

All put back together - again!

Given that it is not the nicest thing to fly I doubt I will rebuild it again.

Ouch. I was about to type in a complement on the paint job and great crafting. It hurts to see great crafting whacked.

The B&Q Diall 3mm SPX sheets I am using seem to be somewhat less fragile and are heat-formable in a way that seems more difficult with a 5mm XPS. And I always have a layer of packing tape over the wing surface top and bottom and a double layer at the leading edge. You guys have seen my many rough landings and I figure that tape helps limit the damage. Dings yes, cracks do not propagate. Down side is that very few adhesives will stick strongly to packing tape.

An observation....and, please don't take it the wrong way... Your crashes are essentially never from poor finger control but from the electrical side of things. I am often let down by my fingers but never by my Futabas. The older T6L Sport was utterly basic but rock solid as is the T6K which adds differentials and expo and 27 other things I don't yet need. Ok, 50 quid more than it should have cost but everything is getting to be 50 quid more than it used to cost. -Jon

jon
Yes my more recent crashes do seem to be electrical/radio related.
The problem is for every crash I record there are many flights that work fine although most crashes do seem to be related to the Hobby King TX6i 'Spectrum compatible' transmitter. The same receivers when bound to a proper Spectrum DX6i do seem more reliable.

By far the most reliable kit I still use is the 35 MHz Futaba Skysport with Corona receivers. They have long aerial wires that go down the fuselage and dangle out the back. Never loose a signal but then there is no one within many miles using the same kit let alone on the same frequency but of course it is now all long out of production.

As reported in "Been flying" the Skyray is under repair after flying through the top of a tree.

There is another similar repair on the other wing but such inserts do not compromise the strength of the plane.
The Skray is now officially "a bit tatty".

I managed to get a video of it flying but pale grey against a light overcast is far from ideal!

During the 4 minute flight it cut out, no power no control, a couple of times but recovered quickly. I can only assume it is radio related as it uses an OPTO ESC so has a stand alone BEC.
Of course sod's law ensured the final cut out occurred just as it was turning onto finals. As you can see it did not turn enough and flew into a tree! :woohoo:
With the aid of my 9 section roach pole, which I had to go back for, it was recovered but with yet another notch in the leading edge!

Just as well I had not repainted from its previous tree encounter.
The nose damage resulted from the 30' drop from the branch!

Note during the flight I was approached by a FPV flyer who had lost plane!

Well I have managed to get it all back together again, again!

Still haven't positively identified what was making it cut out. It works ok at full power at the moment but just in case I have changed the position of the rx and its diversity aerials.
Should be some pretty calm weather once the high pressure area is central over the NW!

After the 20Sep22 crash I intended to not bother to repair it again and to build something else.

But I changed my mind due to the complete lack of damage beyond the destroyed nose.
First job was to 'make good' the broken end of the fuselage.

The battery goes into the hole.
At the same time I have replaced the OPTO ESC and UBEC with a 20A ESC with BEC and "external" heat sink to simplify the wiring inside the cramped cockpit space. Its been tested.
The receiver will be replaced as well.
Now I have just got to summon up the enthusiasm to build a complete new nose section.

The new nose built & added to the fuselage.

The 20A ESC with cooling fins is in place.
Still quite a few bits to be added for the existing canopy to fit properly.
To completely avoid the radio issues it has had up to now I am toying with using a so far unused 35 meg Corona rx. It is 'synthesised' so it needs no crystal.

The Skyray is all back together and painted.

And it does have a 35 MHz rx with the aerial running down the top of the fuselage spine, up the leading edge of the fin and the remaining 10" dangling off the top.
Still needs the decals adding on the cockpit sides but the colour printer has stopped working.