EE Canberra - correcting the Airfix tailplane

[71chally]

The main issue with the newer Airfix 1:72 and 1:48th Canberra kits tailplane really needs to be understood for it to be corrected properly.

 

The real Canberra tailplane has a 10 degree dihedral which it maintains across each half span from the fuselage joint.

Airfix have made the fixed stub part molded on the fuselage level (ie no dihedral), this in effect raises the upper tailplane surface join position too high on the fuselage, even though the main mounting slots and the tailplane are pretty much in the right position. 

The stub also looks completely wrong when compared to an actual Canberra as it lacks the leading edge sweep back, by removing the stubs you eradicate these issues.

Why Airfix did this is a mystery as no other Canberra kit, including their old classic B(I).6 kit features this.

 

To the eye the actual tailplanes appear to simply butt up to the fuselage tail assembly, in reality, it's a bit more involved than that though. 

The tailplane assembly is hinged at it's forward spar and has an electrically actuated drive at the rear to allow it to travel up and down to adjust trim of the aircraft in pitch.  The rear fuselage has a cutout to allow for this movement which is why you can see a clear gap under the tailplane when it is in neutral - to trim up position, usually when the aircraft is parked.

The small section of fuselage above the tailplane is mounted to it, and moves with it, but has a slot in the top to avoid the fin rudder assembly.

There is a tailplane leading edge root fairing fixed to the fuselage.

 

Hopefully these pictures illustrate what I mean, you can see how a small section of the aft upper fuselage section moves with the tailplane, from the hinge point just ahead of the national markings on the fin - to the break point with a white painted aft face.  The fuselage tailcone assembly adjacent to the elevators is fixed.

 

Canberra T.4 WJ874 by James Thomas, on Flickr

 

Canberra T.4 WJ874 by James Thomas, on Flickr

 

Canberra PR.9 XH135 by James Thomas, on Flickr

 

Canberra PR.9 XH135 by James Thomas, on Flickr

 

As said, the Airfix tailplane/fuselage junction stub is molded into the fuselage, this can be completely removed as it is solid plastic, and the remaining area shaped to conform with the correct fuselage contours.

At this stage, an easier fix would be to butt join the tailplane halves into the existing slots.  The tailplanes themselves will then need plasticard adding at the join area to compensate for the loss of span with the removed fuselage plastic.

 

The slightly more involved, but ultimately more satisfying and correct, route is to make the whole tailplane assembly as English Electric did. 

The tailplane can be made into a single assembly by making up a new box structure between the two halves (the included kit tailplane tabs will help you here), and between the tailplane front spar (the tailplane hinge point) and the elevator hinge line. 

Cutting out the corresponding section in the fuselage is the next step.

This will allow for both a more life like appearance and to be able to mount the tailplane at a desired incidence.

 

Back of envelope sketch,

 

030 (2) by James Thomas, on Flickr

Edited July 14, 2020 by 71chally

[71chally]

I was inspired to get on with this modification after seeing Bills excellent PR.9 build thread here,

 

I'm not actually building a Canberra at the moment, but dragged an Airfix 1:72nd B(I).8 out of the stash, just to do the tail mod, it took me an afternoon and the following morning to do, between looking after bleating kids etc.

 

This picture post describes the sequence to correct the tailplane the more involved way, ie making it one piece and making a fuselage cutout.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

As it comes, showing the stubs on the fuselage

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Removing the stubs.  I tried keeping the fixed leading edge root section in place, however I found it impossible to restore the fuselage section properly with it left in place, so I removed the whole thing, as seen on the upper fuselage half.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

If you're going the easier route of just fixing the tailplane to the modified fuselage, this is what it will look like and the gap between it and the fuselage will need making up with plasticard and shaping - pretty straightforward.  Maintain the tailplane surfaces over the plasticard inserts, there is still a good join with the tailplane tabs in the remaining slots to keep the correct dihedral.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Mark out the tailplane profile shape by slotting it in and drawing around with a sharp pencil or scribing, then mark the box that needs to be cut out.  This extends from the panel line running vertically down from the fin, aft to the elevator hinge line of the tailplanes.  Cuting the out box was done with a scalpel at as near to 90  degrees to the fuselage/fin join as I could, it helps here to remove a lot of the plastic on the inside of this area after you make your cuts, mine simply fell away doing it like this.  Razor saw the vertical lines.

It only occurred to me afterwards that the tail cone will have to be removed anyway - to get the one piece tailplane back in! I simply sawed it off at the elevator hinge line.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

This is what you should have, the bottom half of the removed panel (ie below line A) is completely cutaway, so that when fitted to the tailplane it only butts up against the upper half of it.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

You should end up with these bits.

 

 

 

 

Edited July 14, 2020 by 71chally

[71chally]

Making up the new one piece tailplane assembly.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Making up the panel that will join the two tailplane halves, a couple of useful guides is that the elevator hinge line is absolutely straight from tip to tip, and the kit tailplane span should be 102mm (across the elevator hinge line) as measured before making any modifications to it.  The joining panel was made with a 1.5mm piece of plasticard, inserted in the fuselage slot and tracing around the fuselage planform in the area.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Plasticard filler panels were then fitted to the upper tailplane roots, left to set and then shaped by file. They run from the elevator hinge to the front of the box section area, ie the same length as the joining panel.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Joining the two halves of the tailplane to the joining panel, this was far easier, and sturdier than I could have hoped for. 

Ensure that the elevator hinge line is dead straight, and the dihedral of 10 degs is maintained while setting, the join panel is on the underside of the tailplanes.  The tags on the tailplanes do the work for you.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

You should end up with this.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

remember those little bits of fuselage you chopped out, they are ready to join to the upper tailplane halves.  This is best done by mating the whole assembly to the fuselage then setting them in tight position to the bottom of the fin.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

The fixed portion of the tailplane leading edge stubs are made up of 1.5mm plasticard and shaped, using the pencil lines as a guide.  At first they look quite wrong, but when you file them down to the right angle to meet the tailplane dihedral they look fine.  this was actually the most time consuming and fiddly part of the job.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

The underside of the assembly, the arrows are where you glue the unit into the fuselage gap, I'm going to just fix it to the plastic of the fuselage, but you could make up a piece of sprue to run spanwise inside the fuselage to make a larger joining area.

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Insert the tailplane assembly in from the rear.  the beauty of doing it this way is that you can now set the tailplane pitch to how you want it, fully up, down and anywhere between!

I always remember Canberras taxying with tailplane motored up and the elevators pitch up.

Only glue the structure at the leading edge of the join panel, then use a cut off of plasticard to fix to the rear of the tailplane assembly (inside the tailcone area) to set desired the pitch angle.

Finally glue the tailcone back in place, use a thin piece of plasticard to shim it to make up for the plastic lost by sawing it off.

The elevators fit on as normal, but will need a plasticard inserts at their fuselage end to make up the span short fall.

 

 

Airfix Canberra tailplane fix by James Thomas, on Flickr

 

Airfix Canberra tail mod by James Thomas, on Flickr

 

Hopefully this diagram helps a bit, it's a section through the tail area at the elevator hinge line.

 

 

Hope this helps, and please ask any questions if you're as confused as I think you going to be!

 

 

 

 

Edited July 14, 2020 by 71chally

[Troy Smith]

very interesting work James,  and, yes, I'm slightly confused, but that's usually the case so no surprise! 

 

But, does this apply to the 1/48th Airfix kits as well?  and/or other 72nd kits?

 

thanks for  putting this information  together.

 

cheers

T

 

 

 

 

[Van]

Excellent job. I wonder how Airfix got it so wrong...

[71chally]

1 hour ago, Troy Smith said:

But, does this apply to the 1/48th Airfix kits as well?  and/or other 72nd kits?

This should work with the 48th Airfix kits aswel Troy, should be a bit less fiddly in that scale, and more noticeably correct when completed.

 

You could do it with the other 72nd kits, but they don't feature this glaring error like the Airfix one.

If you did want to do it for the purposes of setting the tailplane incidence for example, they would all have their differences with tailplane mounts etc, might work well for the Xtrakit & Highplanes kits as they have minimal mounting areas for the tailplanes.

 

I'm hoping @canberra kid can post some his marvelous Canberra AP extracts which would simplify my description somewhat!

Edited February 9, 2017 by 71chally

[Michael51]

I am in awe of your quest for accuracy.

 

Michael

[Navy Bird]

Excellent work, thanks for posting this.  

 

Cheers,

Bill

[71chally]

No probs Bill, I dare say if you go down this route you would execute it far better than I can.

[Uncle Uncool]

That's an impressive work, James! Clever. Actually, the only way to do it, me guesses.

Whut 'bout 'em Classic Airframes 1/48 Canberra? Are 'em tail planes molded the same way?

Cheers,

 

Unc²

 

P.S: Make this one pinned, Mike. 

[canberra kid]

1 hour ago, 71chally said:

This should work with the 48th Airfix kits aswel Troy, should be a bit less fiddly in that scale, and more noticeably correct when completed.

 

You could do it with the other 72nd kits, but they don't feature this glaring error like the Airfix one.

If you did want to do it for the purposes of setting the tailplane incidence for example, they would all have their differences with tailplane mounts etc, might work well for the Xtrakit & Highplanes kits as they have minimal mounting areas for the tailplanes.

 

I'm hoping @canberra kid can post some his marvelous Canberra AP extracts which would simplify my description somewhat!

Good work so far James, I'd already come to the same conclusion and I'm going to try it on my next 1/48 build. If you don't go so far as correcting the tail completely the least you should do is sort out the kink in the leading edge of the tail plane, Airfix have put a straight bit in the stub part the joins the tail plain to the fuselage, you could build this up so it follows the line of the leading edge of the tail plain, or the way I do it is cut part of the rear end of the tab on the tail plain, this allows you to sit the tail plain further back, wis way you can re profile the stub so it follows the leading edge of the tail plain

  

 

The area marked in yellow at the rear is another think that most if not all Canberra kits is the filet on the rear fuselage this should be removed too.

I hope that helps a bit too?

What drawings do you want James?

 

John

 

Edited February 9, 2017 by canberra kid

[71chally]

Thanks John, that's the beauty of the suggested fix though is that it completely removes all of that molding on the fuselage and it's rubbed down to the bare fuselage section.

The AP pages you posted in Bills' thread are ideal, the ones that show this area.

 

@Uncle Uncool, the CA Canberra tailplanes are mounted in a different way, again though you could do the above work to make the tailplane poseable or stronger, it is actually quite rewarding!

Edited February 9, 2017 by 71chally

[Uncle Uncool]

20 minutes ago, 71chally said:

@Uncle Uncool, the CA Canberra tailplanes are mounted in a different way, again though you could do the above work to make the tailplane poseable or stronger, it is actually quite rewarding!

 

Certainly, James. Will do. Would have to study some piccies of the interior of this tailplane movable unit first, like whether or nay there's sumthin' visible that must be scratchbuilt inside of it, 'n' whut the maximum angle of pitch is.

Thanks, James.

Cheers,

 

Unc²

[canberra kid]

Ok James you got it! 

John

[canberra kid]

More tail plane detail 

John

 

 

[71chally]

Superb pics, thanks John.  

They illustrate really well what the kit modification is trying to achieve.

[71chally]

13 hours ago, Uncle Uncool said:

 

Certainly, James. Will do. Would have to study some piccies of the interior of this tailplane movable unit first, like whether or nay there's sumthin' visible that must be scratchbuilt inside of it, 'n' whut the maximum angle of pitch is.

Well now you can see what it looks like inside,

 

the trim incidences are,

Range between electrical stops;
2 deg12min +/- 5.4min to 3deg 59min +/- 4.5min

Take off position 3deg 15min +/- 2min
after parking, trim set fully nose down and one blip up.

[Uncle Uncool]

Awesome piccies 'n' diagrams, John! Thank ye very much, my mate.

Does 'em colour of the centre section main spar (or the whole interior) vary from aircraft to aircraft?

 

3 hours ago, 71chally said:

Well now you can see what it looks like inside,

 

the trim incidences are,

Range between electrical stops;
2 deg12min +/- 5.4min to 3deg 59min +/- 4.5min

Take off position 3deg 15min +/- 2min
after parking, trim set fully nose down and one blip up.

Indeed! Thanks to ya too, James. So, I take it that, even when the aircraft is parked, the gap between 'em lower edge of the movable tailplane section 'n' the upper edge of 'em tail cone is always visible, like on this piccy ya posted?

 

   

This is such an invaluable piece of info, chaps; thanks to both of ye, John 'n' James.

Cheers,

 

Unc²

[canberra kid]

3 hours ago, Uncle Uncool said:

Awesome piccies 'n' diagrams, John! Thank ye very much, my mate.

Does 'em colour of the centre section main spar (or the whole interior) vary from aircraft to aircraft?

 

Yes they do to some extent, but they a generally white or silver or as in the TT.18 a mix.  

 

Indeed! Thanks to ya too, James. So, I take it that, even when the aircraft is parked, the gap between 'em lower edge of the movable tailplane section 'n' the upper edge of 'em tail cone is always visible, like on this piccy ya posted? 

The gap does close a bit, but never completely, the Americans tried to eradicate it completely but never did

   

This is such an invaluable piece of info, chaps; thanks to both of ye, John 'n' James.

Cheers,

Have you had a look around my web site Unc² ? IPMS UK Canberra SIG 

 

Unc²

 

[canberra kid]

On 09/02/2017 at 4:48 PM, Troy Smith said:

very interesting work James,  and, yes, I'm slightly confused, but that's usually the case so no surprise! 

 

But, does this apply to the 1/48th Airfix kits as well?  and/or other 72nd kits?

 

thanks for  putting this information  together.

 

cheers

T

 

 

 

 

The same problem applies to the 1/48 kit too Tony

John 

[canberra kid]

If you want to get into the nut's and bolt's 

John

[71chally]

Great illustration John, is there one for the tailplane trimming as well?

[SleeperService]

 

16 hours ago, canberra kid said:

Indeed! Thanks to ya too, James. So, I take it that, even when the aircraft is parked, the gap between 'em lower edge of the movable tailplane section 'n' the upper edge of 'em tail cone is always visible, like on this piccy ya posted? 

The gap does close a bit, but never completely, the Americans tried to eradicate it completely but never did

 

Thank You so much for the help you've given in the past and again here.

 

I assume the modifications also apply to the B-57 until I read the highlighted sentence. Is the B-57 in fact different again?

 

[71chally]

The pictures I've seen of B-57s show the same feature with the tailplane, even through to the RB-57F,

 

 

 

Nice detail shots in here, https://acd-ext.gsfc.nasa.gov/People/Newman/wb57_pics.html

 

However, John might know something here that I don't.

 

 

 

Edited February 11, 2017 by 71chally

[canberra kid]

20 minutes ago, SleeperService said:

 

 

Thank You so much for the help you've given in the past and again here.

 

I assume the modifications also apply to the B-57 until I read the highlighted sentence. Is the B-57 in fact different again?

 

No problem, I'm always happy to spread the Canberra love!  

The Americans spent a lot of time and effort aerodynamically "cleaning up" the Canberra, one of the things they were particularly concerned about was the gap under the tail, in the end they fitted a plate to try to fill the gap but as far as I know it made little difference. Roland Beamont flew the prototype B.57A in Baltimore after the Americans had cleaned it up aerodynamically and greatly improved the aeroplanes performance, Bee found very little difference between the B.57A and the standard B.2 it later turned out that the big improvements were down to errors in the test equipment! One thing the gap under the tail did do was cause the movement of the fuel vapor vent from the fuselage side just above the wing trailing edge to the vent mast under the tail plane, early on they found fuel vapor would accumulate in the area under the tail plane and with the electrically actuated tail trim it was thought the two wouldn't be a good mix, so the mod for the vent mast was introduced.

 

John       .