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E-Flite P-38 Rebuild

Is there life after death?

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Pete B - Moderator27/07/2009 01:15:11
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Well folks, you may have seen the unfortunate demise of my Lightning on this thread. Now, I like this aircraft, the kit has been discontinued and, frankly, I can't afford to pursue this hobby at the rate of £3+ per second!

Having read on other forums of the rebuilds of this and other foamies, I'm determined to try and raise a phoenix from the ashes.
 
Before:

 
After:

Once I'd recovered all the bits, I was presented with this:

The first thing to do was to dismantle the hardware and electrics, effectively returning it to kit form, albeit with a few more pieces than when I first opened the box!:


There are about twenty or so pieces now so, from a morale point of view, I've convinced myself that it's no more difficult than building a kit - well, it helps
 
Early inspection of the hardware showed that the starboard motor has had its shaft punched backwards about 5mm. The circlip is still intact and the shaft should not need more than pressing back into place. I'll bench run both motors before I refit them to check true running:
 

Apart from damage to the foam mouldings, the only other items which seem damaged are both spinners (the props are OK); one cowling has split but should be repairable; the wing spar central joiner  needs reinforcing and the outboard ends of the central wing spars (carbon tube) have splintered. Remarkably little serious damage overall!
 
I'll continue in the next post...........
 
Pete
Pete B - Moderator27/07/2009 02:08:30
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 One thing which may contribute to a successful reassembly is the minimal amount of adhesive which seems to have been used in the factory - not something I'd necessarily appreciate but it has its advantages at times like this. I've noticed in other threads that balsa/ply ARTF's have also re-assembled more easily for this reason:
 

Before  I get to the sticking together bit, a technical query. As I'm running 6 servos with a Spekky AR500 Rx, I've used a 3A UBEC like this:


There is not a huge amount of space in the cockpit nacelle and there is an awful lot of wiring, as you may see from this pic. This puts some strain on the magnetically-held cockpit cover:
 

 I'm thinking of perhaps moving the UBEC out to one of the engine nacelles to cut the crowding. The power scheme on the Lightning has one 3S1P Li-Po, centrally mounted with a Y-lead splitting the supply out to the ESC's in both nacelles. I have the UBEC presently connected at the Y-split, adjacent to the battery. (I know this is not the ideal setup but it's the way this model is wired)
 
Questions:
 
If I was to splice the UBEC into the power supply leads in a nacelle, half-way along one of the pairs of power leads, would this be a poor arrangement electrically? I'm concerned that this could reduce the power to the motor on that side or would it just increase the current in the lead (14SWG)?
 
Would it make more sense to just extend the battery to UBEC power supply leads from the existing take-off point?
 
Given that I'm on 2.4ghz, how necessary is it to retain the ferrite ring in the UBEC cable? Leaving it in is not a big issue but, if I can sensibly reduce unnecessary additional weight, I should do so.
 
Answers gratefully received!
 
Now on to the sticking bit. I'm using CA and kicker on the non-structural, easy-to-mate breaks and epoxy on the more crucial or complex joints. I shall also add some reinforcement where it would seem sensible, without going over the top. I do not want to be adding too much weight if I can avoid it.
 
Starting with the simple breaks, I've repaired the wings, cockpit cover and tailplane assembly this evening. It's very satisfying to start to see some order coming out of the chaos!:
 

I recovered just about every scrap of foam from the scene so filling should be no more than necessary. Any dings,cracks and crevises will be filled with an ultra-lite water-based filler I found in a pound shop some time ago.
 
I have some Tamiya Intermediate Blue acrylic paint for re-touching (it's pretty close) and, being far from a model shop, I'll settle for some gouache or watercolour for any black or white areas.
 
Well, that's enough for this evening. I'll get the epoxy out tomorrow...........
 
Pete
 
 

Edited By Pete B on 27/07/2009 02:12:16

Terry Whiting27/07/2009 09:13:18
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Pete,  Although I personally dislike these "jelly mould models",  I admire your tenacity
I think when finished you can honestly say  " I BUILT THIS MODEL"  , and there's
not many foamy flyers that can claim that honour.
 

Edited By Terry Whiting on 27/07/2009 09:15:48

Simon Chaddock27/07/2009 09:28:50
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Pete
That was one heck of an impact!
Nice to see someone who looks at the bits and thinks "how do I repair this?" rather than "where is the bin?"
Your rebuild looks amazing and hopefully should give some encouragement to others who might think things are beyond repair.
An impact that pushes a motor shaft back may also have bent it, check very carefully.
 
Hopefully when complete it will be case of "you can't even see the joins"!     
Simon Chaddock27/07/2009 09:36:15
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Pete
I would suggest that the UBEC current draw is so small, compared to the motors, that it will not make a great deal of difference where you mount it.
 
I purchased a similar for my Hamilcar and that has nine (small) servos and even then I did not use it as the ESC BEC (2A) seems to handle everything ok.
Tim Mackey27/07/2009 11:18:15
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I agree. Splice away Nice job so far Pete, and I hope plenty of people are watching this, to prove that almost anything can be re-built given the patience and tenacity.
As for the ferrite rings....not required with 2.4Ghz stuff, and any that come prefitted to any UBECs etc that I ever have, get broken and removed before use.

Edited By Timbo - Moderator on 27/07/2009 11:19:35

Myron Beaumont27/07/2009 11:28:45
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Pete
Well done so far . Doesn't look half as bad already  does it ? Wouldn't surprise me if it ends up better than it was originally ie glued together properly being as you mentioned it .Keep it up (excuse the pun)
Klippy27/07/2009 12:24:46
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Great stuff, keep up the good work.
Pete B - Moderator27/07/2009 19:56:24
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Hi All,
Thanks to everyone for their messages of support - it's nice to see so much interest!
 
I've made some progress today and I've been very surprised just how quickly it has come together. It's a case of test-fitting each part, making sure that any 3rd piece will fit in the sequence of glueing, and then relying on the magical qualities of modern adhesives! CA and Devcon epoxy are the only adhesives I've needed so far.
 
The battery bay has been fixed and the central joint of the wing spar epoxied and taped. The socket ends of the spars, which had splintered, have been bound and CA'd:
 
 
The first point of impact was the port engine nacelle, closely followed by the nose!! The foam has compressed and distorted slightly on the outside edge of the nacelle.


 The port nacelle, because of the distortion, needed the foam firmly held in place whilst the epoxy set
 

The break lines clearly show the direction of the snapping forces crossing diagonally from the port nacelle through the fuselage.
 

I've kept the amount of additional reinforcement to a minimum - it adds weight and the designer arguably felt it wasn't necessary. I've used a small panel of 1/64th ply on the boom breaks just behind the wing, mainly to provide a larget glueing area.


I wasn't happy about relying on the boom joint setting and maintaining the correct incidence for the tailplane asembly, so I've used a couple of toothpicks to provide a bit of support for the tail. I had thought of using a bit of carbon but that seemed to be over-engineering, considering that the original has no reinforcement whatsoever:


Tail assembly setting, taking care to eyeball  the incidence carefully:

 Better continue in another post...................
 
Myron Beaumont27/07/2009 20:04:09
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Pete B
Fantastic ! I like it -- Carry on .Thanks for the photos whilst you're doing it . A real modeller you are
Pete B - Moderator27/07/2009 21:08:21
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It's looking a lot more like what I found in the box now!:
 
 
 

A bit battle-scarred, admittedly, but I found this filler in a pound shop some time ago. It's water-based and incredibly light:
 

I've been filling a few cracks and dings with it and, once dry, I'll embark on touching-up the paintwork. The recognised colour for this model is Testor's Medium Blue, which I haven't been able to find. It has been suggested that the Tamiya Acrylic Intermediate Blue is a good match. Unfortunately, it's a bit on the green side to be a good match, so I shall have a play with some gouache paints to see if I can get a bit closer. If I can't then we'll have to imagine that the repair shop used whatever was available (there was a war on, you know!)
 
This is how she looks this evening, 48 hours after the mishap. The 1st session of filling has been done:
 

  
I've still got the motors to sort out and one of the cowlings to repair. It seems they are available in the UK but I'm reluctant to pay £7 postage right now. The cowl can be taped and CA'd - and stand-way-off-scale rules will apply! I might have to bite the bullet and get the spinners though. The rest of the hardware seems ok.
 
Whilst the cockpit canopy is off, I should take the opportunity to get shot off the silly micro-midget pilot E-Flite found for the model: 
 

Now, I know Matt Halton has hand-carved a brilliant pilot in foam for his P-38 (and Sea Fury). It's much closer to scale for this model and really looks authentic. Does anyone know if Matt has ever done a how-to thread on carving them from foam? My modelling skills will never get within a million miles of his but a few pointers as to shape and painting would be really useful for many of us. Pretty please, Matt?
 
Unfortunately, life has a habit of getting in the way of important things like modelling, so I'm off to see my mate in the Dordogne tomorrow for a couple of days. He's a railway modeller and cannot begin to understand how we can launch our precious models into the air and risk damaging them! I admire his skills in making individual roof tiles out of cut-up cigarette papers, for instance, and the realism he puts into his building is amazing.  It takes all sorts to make a world, doesn't it?
 
I'll update this with my progress later in the week.
 
Pete
 
 
 
Pete B - Moderator27/07/2009 23:23:56
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Thank you, Myron - I take that as a real, if undeserved, compliment! The reality is, of course, is that my parsimony extends beyond the depth of my pocket
 
Pete
Klippy28/07/2009 06:40:35
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Hi Pete, I've seen others suggest making spinners out of blue building foam. It seems you make a back plate out of thin ply, secure it to the motor shaft, glue the rough cut foam to the ply and spin the motor while sanding. You could of course use an electric drill, loosely held in a vice.
BB28/07/2009 07:12:11
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Brilliant re-build Pete.  Really !  Very encouraging.
 
BB
Pete B - Moderator01/08/2009 01:25:22
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I've made a bit more progress today. The motors have been checked and are fine, as are all the servos.  I've moved the UBEC (minus the ferrrite ring!) to the starboard nacelle, the side which has only one rudder servo in the intake pod, so to an extent it will help balance the port nacelle, containing those for the elevator and 2nd rudder.
 
Finding that the Tamiya paint wasn't that close a match, I've come up with some Reeves gouache, with white, lake blue and a dash of black close enough to keep me happy:
 

 The wing stubs are attached to the nacelles by a pair of long 2mm bolts, inserted near the supercharger detail. On the port wing, I found that the plastic collars had been compressed into the foam, which meant that the bolts, tightened down, did not secure the wing. The plastic collars were removed, the depression filled with Magic Filler, and the collars CA'd into the filler. They're nice and secure now!:
 

The filler has been used where necessary but it helps to get it about right first time. Where there is an excess, it requires some delicate sanding to smoooth it down without damaging the surrounding foam. I'll certainly not reach a machined finish with the filler but it will, like the paint match, be good enough for a foam model such as this.
 

The motors have been remounted and, having learnt from the Sea Fury, I've stabilised the end of the mounting stick to prevent looseness. Re-gluing the port motor stick (the side which bore the brunt of the impact) seems to have introduced a degree or so of right thrust to the port motor. I've corrected this with an additional washer between the motor and the mount and everything seems to be pointing roughly in the right direction now!
 
The port nacelle cover wasn't too badly damaged so tape, CA and a touch of filler, together with a lick of enamel, should be fine. The spinners issue will be addressed after I've got her flying, I think, but foam seems to be the way to go. As you can see, she's well on her way back this evening:
 

 


The rewiring has all been done and tests ok. The original auw was 1140g, so it will be interesting to see what the rebuild has added.
 
A bit more touching-up to do and I'll soon have a chance to see her where she belongs!
 
Pete
 
ken anderson.01/08/2009 07:45:42
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hello pete--it's me ken(get the match's)anderson......you have made an excellent job--i'll put the match's on hold-well done.....
 
             ken anderson..........
Klippy01/08/2009 07:54:29
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Great rebuild
BB01/08/2009 08:46:51
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Pete, its looking cracking.   How long till you give it some airtime ?
BB
Eck01/08/2009 09:19:17
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Great job, Pete. Shows what can be done with what might appear at the time to be a "write-off".
Pete B - Moderator03/08/2009 00:26:53
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Well, I've finished her!  Looking just a little battle-weary, perhaps, and sporting a new yellow nose, but a lot more promising than a week ago. I had to replace one of the prop adapters, which was running out of true, but apart from that, it's all fine. Net weight gain is just 18g, making an AUW of 1158g.
 
Having spent an hour filing away at a piece of foam this afternoon, I've decided I'm no Michelangelo, so da little guy stays - capiche?
 

 
If I can pluck up the courage, I'll fly her tomorrow!
 
Pete

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