Thursday, 15 March 2018

Antonov An-225 Mriya - a PSS legend

In 1995 Simon Cocker made a rather large PSS glider - the Antonov An-225 Mriya ("Dream").  At 6m span, she made it into the Guinness Book of World Records.

Alas, in about 2006 the model suffered a crash on finals when the forward hatch blew open which resulted in a large un-commanded yaw manoeuvre.  The aircraft would not respond quick enough to corrective action, and she went in at just below cruise speed. 

The aircraft punched clean through a bush that slowed her a little, then parts starting hitting the ground.  The nose hit hard, and pulled the mounting hardware clean out of the main fuselage section, pivoting backwards and leaving a large gash in the port LE. 
Next, the main fus section hit more or less straight in - this was the big hit.  The main bulkhead ploughed  through the soil then fractured halfway up, blowing out a large section of the bottom of the fuselage.  This shock load flexed the wing tip panels so hard, the scarf joints cracked in the spars and the veneer creased on top.  The entire fus flexed, creased the veneer in 4 distinct lines, then righted itself. The tailplane also suffered here with a flexing stress crack of the veneer.
Most of the weight of the plane is the centre wing section - this carried on going forward, pulling the bolt plate clean out, fracturing a large 1/4" birch ply tongue, and shed all the engines.  5 out of the 6 engines were damaged, one badly.  The fins - nearly 2 foot high each - were completely unscathed from the crash.

When I picked the aircraft up she was in a sorry state, having sat dormant in a garage for the best part of 12 years since the impact.  Simon and some of the PSSA guys had managed to clear the crash site rather well, and just about every part was recovered though - making the rebuild a fair bit easier.

I have taken pics of most of the repair process, and probably wont blog them all, but here are a few.

The nose rejoins the aircraft on its latches for the first time in a long time

Port LE repair

Front of main fus repairs

Repairs continued

Centre wing flap reattachment

This has put a big dent in all the other aircraft builds and repairs, but they'll all get done, eventually.

Monday, 12 February 2018

Douglas SBD "Dauntless" for PSS - Weathering and finishing up

The SBD is coming along well, with only the wing servos left to install.

I mounted the engine in the cowl with a medium balsa brace (painted black) across the back of it:

So I thought it's about time for some weathering on this beastie:

Oh, and I've painted those control horns now too, to match the rest o the airframe.  Not a lot left to do - underside weathering, servos in the wing, balance and set up on the Horus.

Thursday, 8 February 2018

Douglas SBD "Dauntless" for PSS - new (quick!) build

The SBD was a pretty sturdy and effective aircraft from WW2.  Not only a dive bomber, they were used as scouts for the carrier fleet and due to their overall ruggedness, the pilots took no crap from enemy fighters and engaged them aggressively when threatened. 

Hobbyking do a lovely all-built-up ARTF SBD for not a lot of money, and I splashed the cash a week or so ago for one.  Of course, they are set up for IC / EP with an undercarriage etc, but they also come with impressive dive brakes and centre flap; some lovely scale detailing on the covering; a decent cockpit set; a glassfibre cowl; and of course retracts.

Hefty all-electric retracts:

Lovely split dive brakes: 

An FG cowl:

A fattish semi-symetrical section:

Nice detail all over, really: 

So, to work!  Retracts out, centre flap servo hole boarded up (I will do this differently), e-flight bomb release slot added:

The retract wells get covered up by some lovely heavy-plastic gear doors (not shown yet).

Wings joined with wood glue on the heft quarter inch ply joiners:

Cockpit detailed up, re-painted, and weathered where necessary.  I converted the single-piece cockpit to the four-piece type as shown in the full size photo above, and as used in combat:

9 cylinder radial drawn-up and printed, pushrods added, ready for primer:

So she's about like this at the moment - servos and control rods just going in, then some more weathering, and then the serial decals etc.

More to follow!

Tuesday, 30 January 2018

Typhoon flaps and ailerons

Build continues apace, and with the garage still being used by the builders to store tools and stuff, I've not been able to get anywhere near all the glassing I need to crack on with.  I'm going to try glassing some smaller bits indoors in the workshop this weekend, hopefully that goes well and I can crack on a bit.

Anyway, very heavy and bent flaps from the original model have been replaced with hard balsa items that will be glassed on one side :

Original at top, new at bottom
This seemed to work well in the wing, so I made the other three :

The ailerons were fairly wobbly and of poor build quality, so I've replaced them as well:

Flaps attached, and port wing with new aileron too
50m of servo wire purchased, ready to kit all these wings out :

So that's everything but the rudder replaced in new balsa.  I wouldn't have been happy unless I'd done this, as they were all in poor shape.  Just means lots to glass!

Anyway, I've just purchased another PSS aircraft, this time an ARTF from Hobbyking.  It's a prop warbird from WW2, and will need very little work to get ready for the slopes - I've been taking photos as I go, so will update shortly with a build blog.

Looks like April will be a busy month for maidens :

HET Dasault Rafale
New project PSS 60"
C17 133"
Hawker Typhoon 106"

Let's hope the weather plays ball.

Sunday, 7 January 2018

Typhoon wing centre section

Back from holidays, and back into the workshop for some Tiffie action.  I've gone around the wing and used P38 filler to get rid of the worst of the offending dents and hollows, now I need to sort the undercarriage wells.

Started off by gluing in little noggins to support a top plate :

Here is the top plate, being cut to size.  I used 3mm liteply :

Now glued in and pinned down :

Then filled and sanded when dry :

Time to fill in those truly horrible servo boxes with 3mm medium balsa linings :

I was on a roll, so made up 5 more for the other wing servo bays :

More soon!

Friday, 5 January 2018

NYE flying, and happy new year!

Well, 2018 is here, and many lovely flying days await us, I'm sure.

Over the holiday period, I managed to meet up with some PSSA pals, and get a bit of flying done on the Great Orme, in a stunning 45mph SW wind on the best slope.  The F15 and Fouga both flew well, but both were damaged on the ground in separate incidents unfortunately, both easy repairs though.

Friday, 8 December 2017

Typhoon work continues - cockpit and spars

I picked up a Hurricane 1/5th scale super dash kit from Mick Reeves models, along with a gun-sight and compass kit.  About 3 hours to get this far:

And here it is - all done, and a bit of dry-brushing later:

I mounted the fuselage on the centre section to check things over around the cowl mounting.  I have some filler work to do around the wing blend too:

The centre section spar tube gluing up to the old centre spar:

Once all done, the anti-rotation pin assembly was also let-in to the back (10mm carbon rod and tube).  A lot of the tip panel has been sanded back here too.  The fit is lovely, all slides together and no slop:

The final tube now laid up and setting:

Not very exciting yet, as it's a lot of repetitive work making tube mounts and clamping stuff up, but she'll be a solid wing again soon that can be sanded back and readied for primer in the near future.

Thursday, 30 November 2017

Typhoon Wing Work

So I got the Typhoon wings in from the shed, as I need to start looking at how the cowl fits, and as that makes in and around the centre section of the wing, I need to have that near for testing.

Get it in the workshop and...

Hmmm, yes it is a bit of pain.  OK plan B then - cut it up with a circular saw...

This was always something I was going to do at some stage, to make the aircraft more transportable and storeable (is that a word? it is now!), plus the wings are in a bit of a sorry state.  There's a couple of creases where it looks like she's had a wing in the dirt at some point, some veneer had lifted, the TE was a bit bent here and this'll make it easy all round.

The flap servo boxes were odd...not even tied in to the bottom skins! 

Same on the ailerons..not great : 

I then started removing hardware from the retract wells.  Here's I have pulled about 2 pounds worth of half inch ply that is heading for the bin: 

The tip panels then needed slots cutting in for a new joiner / spar system - note that the full depth ply spar only runs into the tips by about 5 inches - again not what I wanted to see, but glad I've found it :

Similarly, the centre section gets gutted a bit for joiner assembly access.  Here, the spar runs full depth and width - lovely : 

So the joiner then - 38mm OD aluminium. Oh yes. Quite cheap and quickly delivered by SLEC : 

I chopped the joiner in half (1.5 feet per side) and chopped the phenolic outer into quarters (9 inches each).  The first of the outers was then joined to a 3mm liteply back plate that'll act as a shear web in the tip panel, and the glue area was increased by using half inch triangular section balsa.  The whole lot bonded with gorilla glue : 

Dried and solid now, and the other three outers in the background with their balsa end-caps added :

A quick test-fit in the tip panel, nice and tight : 

Laid into the tip section with the spar inside to check angles: 

OK, enough for now, time to get the first side glued up!