A4b crash 03August26

As I reported in "Been flying" I had a major incident with the A4b with wings that ended up in a tree. After recovery it looks like this
 
With not insignificant damage to both wings.
    
With wings repaired a start had to be made on the much bigger complete rebuild of the nose.
First a new printed former replaced the damaged topmost one that still had a complete circle of fuselage skin around it, F9
 
To get access all the "electrics" and servos had to be removed.
When the glue was set it meant I had a firm(ish?) base from which to build the nose up to the removable nose cone using formers F8 to F4.
 
The nose cone itself will be a repeat of a LW-PLA structure that has three LW-PLA formers inserted into it.
Just as well I still have all the stl files!
Looking back over the record the nose of the A4b has been rebuilt 6 times over the last 8 years! Jul 18, Aug 23, Sep 23, May 24, Aug 25.
The Aug 23 repair was also a major rework to replace the 70mm EDF on a 3s with a UAV motor driving a 5 inch 4 blade prop on a 5s, a process that shaved nearly 20% of the all up weight.
VTO does have risks, anyway, on with the 7th nose rebuild.       

 

Hopefully the tricky part of the nose rebuild is over with four full length planks supporting the top former (F4). Former F8 is also glued in. To save Depron as much as possible of the existing nose skin is retained allowing some of the planks to be significantly short.
 
The positions of the three intermediate formers (F7,F6 & F5) are marked on all 4 planks so it's just a job of glueing them in
 
As additional planks are added the structure get more and more rigid.
Whilst waiting for glue to dry I printed a new nose cone in LW-PLA with a 0.4mm wall "vase" printed.
 
Slow but it does give a smooth finish with zero blemishes.
As it is just a "skin" it has 3 LW-PLA formers glued inside for stiffness.
 
The bottom one is virtually identical to the top fuselage former and with magnets set to opposite polarity. The complete nose cone weighs 10.2g
 
Next task is to complete the planking. 

Slightly off-topic, but this might interest Q, amongst others - 

For what is meant to be a fairly technical video why the rather idiotic introduction?
Much of the later rocket development falls in the "what if" category.
Although the V-2 went at high speed (mach2+ ) it was just a ballistic trajectory with no control once the gyroscopes set it on its way.
It was judged that applying a degree of aerodynamics would significantly increase the potential range but very little was known about supersonic airflow.They did build a small supersonic wind tunnel that gave up to mach4 for short bursts. Post war it was moved and used at Farnborough!
All development work on extended range rockets was stopped in 1943.
Almost out of desperation in 1944 Von Brain put what were considered the best known design of a "high speed" wing on as standard V-2 (A4) but he had to call it the A4b so it could be considered just a modification and would not impinge on the top priority V-2 production.
This diagram shows how the winged V-2 might have been used.
 
 It was actually test flown twice in 1945. In the first launch the rocket itself technically failed (not uncommon) but on the second it reached full height and speed but not surprisingly the wing failed as soon as any sort of glide at supersonic speed was attempted.
There is a video of that launch but it is not available on YouTube. A picture from that video.
   

Interesting fact in the video "The V-2 rocket programme consumed a bigger proportion of the German GDP than the nuclear programme did of America's".
Of course the B29 Super Fortress programme exceeded it as well as thus indicating just how strong the US economy was at the time.  

If you had been 'following' "Lord Hardthrasher" for a while, the looney intro would make sense! 

Still slow going but at last I have arrived at "the final plank".
 
What I had forgotten is that in the original construction all the formers were Depron so each plank could be secured in place with a pin into each former allowing the next plank to be installed.
With the formers being printed in PLA it is not possible to drive in a pin so each plank has to be secured with small bits of masking tape so precluding any work on the next plank until the glue is dry enough so any masking tape can be safely removed.
Before the planking was complete I resoldered the motor wires to the ESC to check it still worked. To my relief I had thoughtfully marked ends of the motor wires to ensure they were soldered back in the correct order. I does indeed work but of course not yet tested at full power!
Quite a few small localised repairs to do on the fuselage but at least I know it will be finished.
 
 

Now it is all structurally complete and painted.
 
The only bit left to do is to replace the Lemon "stab" receiver and then plug the servos, ESC and UBEC into it.
 
The Depron battery box is sized to take either of the rather differently shaped 650mAh 5s LiPo. They weigh different too, 88.6g and 67.3g. I fear one is not a true 650mAh.
As the whole object is a VTO the initial flight will use the lighter one.