Wednesday, 30 March 2016

Some B52 repairs & modifications - part 1

The big silver BUFF will shortly be entering bombing duties with the PSSA, in a sub-event that I created for some extra fun at our meets.

A few people have thankfully shown interest, so I decided on using the BUFF for my entry to the competition and got her onto the bench for modification.  I think she will be an ideal candidate, as with lots of wing area she can carry a good load, as well as having crow brakes for parking over the aim circle to drop the load off!

The last time I flew her off my local slope, she required buckets of trim and wasn't her usually comfortable, groovy self - so I had a quick check over the control systems.  Oh dear, I'm glad I did.

The aileron horn-holes had gone oval, giving each aileron a lot of free play.  Like half the required movement, which was bad.  I'd also lost (yet another) hinge on both flaps, so it's time to rip it all out and start again.

Firstly, I dug a good half-inch hole out around the screw hole, and removed the foam :

Next up, I chopped some 1/2" hard balsa oversize, and Gorilla-glued it in :

The next day, this was sanded back to profile, a new hole drilled through, and some thin cyano wicked into the exposed cross-grain.  Once dry, the steel bolt is dropped back through : 

Then tightened up with the addition of the aluminium base, and plastic top :

Job done! 3 more to go.

Tuesday, 22 March 2016

Thursday, 17 March 2016

Surprise! Albratross update

Shona and I cut 8 wing panels last night for the Albatrosses.  The fuselages just need the jet intake detail adding, then they will be ready for cockpit moulding, which I am dreading!

Anyway, here are the wing cores.

Tuesday, 15 March 2016

M55 Mystic - no longer a design study

After speaking to some fellow modellers recently about the M55 design study, I was told of this monster that didn't as far as being finished.  She now has my name on her!  I just have to pick her up and drop off some pound notes..

Just a bit big then?  That should put the wingspan at the 6 metre mark I believe.  I can't wait to pick this one up.

Go big, or go home :)

Monday, 14 March 2016

C17 fuselage assembly

I tried to post this a few times from the mobile app, but it didn't want to play ball.  Oh well, here it is.  First test assembly of tailplane / fin / rear fus / front fus out in the garden.  Can't be arsed to mow the lawn yet (I usually don't bother till after Easter) so it's a bit untidy I'm afraid.

I'm quite happy with the weight at this point, so blocking-out will start on the nose section shortly.  Carbon joiner tube is on it's way, then I will lay up some sheaths for the fuselage sections.  The first wing panel is in the press with its veneer on this morning, so I hope that looks good by the time I get home tonight.  Spar boxes next!

Friday, 11 March 2016

C17 tailplane assembly

The veneers were sanded down to be flush on the foam cores, and 1/4" balsa LE and TE's added.
Some time later...

The tailplanes are now sanded to "first pass sand" level, and one elevator is done - the other needs a quick kiss from the hand plane then a sand from the Perma Grit. Spar grooves have been let-in too; wing tips added (1/2" soft balsa-1/8" liteply core - 1/2" soft balsa); and the hardware for mounting is cut and ready. By the end of the day, this will all be glued up - currently this is a dry fit.

Here is an elevator sanded up (square) and laid in position ready for hinges to be marked, and the front to be rounded.  This assembly should be close to being covered by Monday morning - there isn't a great deal of work left in it.

Wednesday, 9 March 2016

C17 tail work

I have veneered the fin and tailplane now.  I am starting the marking up of elevators and servo positions, ready to start cutting through the skins.  You can see a standard size servo holder on the one half for scale...

And here is the fin-top - an all lite-ply structure that the tailplane halves will be mounted in.  This then bolts through onto the fin, and allows me to change the incidence angle if need be.

A few scribbles for the working out of positions of items always helps.

A10 fame!

Quite chuffed with the amount of column inches I got from Simon in this month's RCM&E.  Many thanks Si, I owe you a point or two!

Monday, 7 March 2016

C17 wiring diagram

I forgot to post this one earlier, as the image is held locally and not on my mobile, apologies.

Here is the proposed wiring layout for my C17, so I can write down extension lengths and required numbers of pins & connectors.

C17 formers and tail parts

Well, all foam parts are now cut for the first C17 (and some bits for the second one too), so some more woodwork-work is being carried out now.

First, the fin was cut into 3 pieces to hold the tail spars.  As the tailplane is quite wide, I didn't want the fin to flex (or potentially snap under severe oscillations) with side load from the tailplane - thus two 40mm wide liteply spars run uninterrupted from bottom to top.  The foam was Gorilla-Glued around these spars.

Same picture basically, at two angles.  Oh well.  You can see (just) in the second one, some holes bored through formers - they have all been treated thus now.  Lots of weight saves I hope!

The 4 big spruce bearers bracket the undercarriage pods can be seen too.  These will give a decent, firm structure under the skin of the aircraft for launching and landing on.

The main fus former that holds the wing spar has been hollowed slightly and reinforced around where the spar box fits.

Net weight gain / loss is zero, so at least its stronger where it needs to be.

Veneering parts tonight!

Friday, 4 March 2016

C17 "assembly" pictures

I wasn't sure whether to post this or not, as one photo is all wobbly, and the other is full of mess where the bathroom is getting refitted (not by me, thankfully!).

Anyway, here they are.

Yes, the rear fus isn't straight, and it wont actually be straight until it starts to see glue - it doesn't self jig very nicely.  In fact nothing as been glued yet, other than F1 an F2.

By the time the weather improves enough for me to actually mow the back garden, the wings should be veneered and the fus should be moved along well.  That means I can "bench fly" it in the garden, which is always one of those points where you think - "Yeah, let's get this finished!".

Thursday, 3 March 2016

C17 former change

I have been building up the C17 carcass, both front and rear fuselage sections, in readiness to build the spar box in - one of the first major structural jobs to do.  Some of the formers (if not all, come to think of it) have now been hollowed out in the middle, and some from the rear section will also get a bit of chain drilling as previously mentioned.

Longerons have been made up and joined, and dry fitted into the structures for checking purposes.

Messy!  It's hard to move stuff around much at the moment, due to the wings being in a fragile skin-less state.

F9a & b, which are at the fus join, require some reinforcement.  The 4mm ply isn't strong enough, and even before it is fitted the former is a bit curled up.  Not what you want at the joint, as it will be the devil's own job to square everything up later.  I decided to remake them out of 8mm, and do a bit of access hole creation.

It's messy in the outside workshop too! I need a tidy up in here, as I have some spraying to do again soon.