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English Electric Canberra

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Andrew Price 202/01/2015 21:52:21
816 forum posts

Erfolg. I seem to remember many, many moons ago seeing comparitive pics of the UK & US Canberra cockpits. The UK was all exposed pipes and wiring and very tatty looking. The US version was as neat and tidy as my car without a single pipe or cable to be seen.

Simon Chaddock03/01/2015 01:29:17
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Erfolg

Each motor draws 7A so I reckon I can just about get away with a JR. In fact on a full power test it was the factory fitted battery wires that got just warm to the touch not the JR connector. wink 2

From what I can find out it would appear that the state of RAF Canberra cockpit depended on the number of equipment upgrades (of which there were many) coupled with the fact that there was access to the nose on the bomber versions which made the inside of the fuselage visible.

The B57 cockpit was of course totally enclosed so none of the 'stuff' in the fuselage could be seen.

Simon Chaddock04/01/2015 23:53:29
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The battery box built into the lower part of the fuselage former.

Battery box

It extends over 2 formers.

The battery slides in.

1000mah 2s

This is not the actual flight battery but the 30c 950mAh Nanotach is the same size (according to HK!)

With the battery in place it balances at exactly 30% root chord which 'feels' about right to me. Famous last words! wink 2

The radio has been tested and the gyros work, although the degree of surface deflection even at maximum gain is surprisingly small. The gyros also switch off using the 'flap' switch.

Next is the hatch.

Simon Chaddock05/01/2015 19:22:18
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The battery hatch.

Battery hatch

It also holds in the radio and is held closed by a tiny magnet.

I am now at a dead stop until the replacement servo arrives.

Edited By Simon Chaddock on 05/01/2015 19:23:02

Simon Chaddock17/01/2015 01:01:44
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With the delivery (at last) of the servo and flight battery work can resume on the Canberra.

Now structurally complete.

Complete and covered

given the absolutely dreadful weather at the moment I might as well paint it in the appropriate 'night intruder' camouflage. I have found an all black underside actually stands out very well in day light!wink 2

32" Span (810 mm) and weighs 7oz (198g) ready to go. I would expect the paint to add no more than 1/2oz.

Edited By Simon Chaddock on 17/01/2015 01:04:24

Dave Hopkin17/01/2015 01:13:43
3672 forum posts
294 photos

:Looking great Simon..... so delicate.....

Colin Leighfield17/01/2015 01:58:07
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Looking at the Canberra and knowing that Bill Petter's previous design was the Westland Welkin does make the mind "boggle" slightly! Talk about a quantum leap in thinking. While still at Westland he had considered converting the Welkin to jet engines, probably not a good idea. Also when you think that while he had deliberately set the tailplane high on the Whirlwind and Welkin to keep them out of disturbed airflow and blanketing effects from the wing, he didn't consider it necessary on the Canberra to do the same thing and clearly it wasn't. At the same time the smaller but similar in many ways Meteor did have the Westland type high tail, but Gloster didn't consider it necessary on the single engined "Ace". All very intriguing.

It looks as if you've got another good flyer on your hands here Simon.

Colin Leighfield17/01/2015 02:02:40
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I forgot, although the Ace didn't have the high tail originally, it was altered later and it was that same tail that was then fitted to the Meteor 8 after the Ace was abandoned. Sorry. That's one I haven't seen modelled yet, but I bet somebody's done it.

Simon Chaddock22/01/2015 19:58:58
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5679 forum posts
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A bit of a gap as painting always seems to take ages but it is now virtually finished.

Complete painted

As I feared the paint and glossy finish (well sort of!) is quite heavy adding 0.4oz (12g) or about 6% of its 'all up' weight of 7.5 oz.(213g).

Not entirely happy with although I expect that will change if it flies nicely!

Just need some passable weather.

Edited By Simon Chaddock on 22/01/2015 20:19:12

Phil Cooke22/01/2015 20:50:39
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2535 forum posts
1790 photos

Looks lovely that Simon well done!! All the best for the maiden - Weather on Saturday is meant to be lovely if you can combat the cold!

Mark Kettle 122/01/2015 20:51:06
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2519 forum posts
1541 photos

Nice Simon, nice model good luck when you fly it. yes

Electriflier22/01/2015 21:21:10
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474 forum posts
1210 photos

Another work of art from Mr Chaddock - good luck on the maiden yes

Simon Chaddock24/01/2015 22:23:28
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5679 forum posts
3018 photos

I was concerned that the paint weight would have shifted the CofG aft so I taped on 0.3g of nose weight to bring the CofG to 30%.

It was calm enough this morning for its maiden. smilesmile

Just two short circuits as it was still seriously tail heavy.

Rather than add more weight which would effect the performance it was obvious that the battery just had to be moved and quite a bit at that - about 3".

At the moment the battery slides forward from the hatch and is almost completely 'buried' in a box. Technically it would be possible to extend the box so the battery could be pushed forward still further but obviously it would have to be puled out by its leads! smile o.

A bit of surgery.

A big hole in the lower skin where the battery has to end up.

Battery box extension 1

The battery box extended 3" carefully matching the existing.

Battery box extension 2

The cut out fuselage skin glued back in.

Battery box extension 3

A bit of filler and a paint touch up and its done!

The CofG is now at 27% with no nose weight. That's 2% further forward than it was for its maiden with the nose weight.

Hopefully a video next flight.

The only real disappointment so far is the 3 axis stabiliser. Even with the sensitivity turned right up it only moves the control surfaces a very small amount (less than the 10% trim movement) even with the most violent movements.

It can be switched off from the Tx so once I have the Canberra flying properly I can see how effective it really is.

Toni Reynaud25/01/2015 09:53:22
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423 forum posts
58 photos

This video might be of interest.

Simon Chaddock27/01/2015 23:09:17
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3018 photos

I also wondered about its decalage - the angle between wing and tailplane.

Following scale I set the tailplane parallel to the fuselage datum however the wing has significant incidence. I fear the CofG would have to go a lot further forward to compensate. Perhaps it would be simpler to fly with less wing incidence.

To physically alter the wing incidence would require virtually rebuilding the whole plane but the tailplane incidence could be changed by cutting it free from the fuselage, increasing the size of its the slot and making good with tapered inserts.

Tailplane insert

The tailplane leading edge has been raised by about 3 mm.

Now just need some suitable weather.

Erfolg28/01/2015 02:19:04
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11706 forum posts
1309 photos

I am not sure there is a problem, other than if the incidence/angle between the two surfaces is to large, you either need to trim the tailplane with up or down trim to achieve level flight. Not good news I agree, in that the drag from the tail surfaces are now higher than ideal.

Perhaps the one incidence that matters a little more, is the wing to body, as this determines the sit of the model in the direction of flight, either being nose high or low. Again with a drag penalty. But as we know, the ideal sit occurs only at one speed. As long as we are not extreme with our incidence, more an academic point on a model aircraft, than a major issue.


Simon Chaddock28/01/2015 13:44:22
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5679 forum posts
3018 photos

Erfolg

My concern was not so much the drag from the down elevator required but the fact that the tailplane becomes an under cambered lifting surface. The wing on the other hand is a truly symmetrical section.

In this sort of condition there is a real possibility it can become longitudinally unstable with speed hence my desire to get it to fly with the elevator 'neutral' with the tail plane but without adding weight. wink 2

Erfolg28/01/2015 14:56:46
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1309 photos

From real experience of flying models, many of which you will have seen with the elevator either pretty much permanent up or down trim permanently set, have any caused pitch problems from observation.

I have experienced problems from poor linkages with gliders at speed, where the push rod has deflected, allowing more down trim due to the deflection, hence even more speed. I do not think I have been aware of pitching moments due to camber and speed on the tailplane being an issue with RC models. Although we did see many what appears to be now strange tailplanes with FF and in the early days of RC, from cambered tailplanes, as per the wing or inverted.

Of course i have to ask how fast do your DF models get?

Now having changed clubs, I see a lot of fast DFs, non of which seem to have any control issues at speed, or when slower.

One of the nicest I have seen, is a U2, which flies like a glider.

I think you are possibly overly concerned, due to your experiences with the rearward CG, which we all know causes heart stopping moments, particularly if not dead calm.

Simon Chaddock03/02/2015 00:04:43
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5679 forum posts
3018 photos

Weather was calm enough this morning to give the Canberra another go with the tailplane incidence altered.

Still a bit tail heavy as I had not pushed the battery as far forward as it should have gone but it seemed to fly reasonably well.

The rather erratic approach was to do a pancake landing to minimise damage to the battery hatch which had opened and was hanging down.
It seems to have sufficient thrust and should be a bit less twitchy with the battery in its most forward position.
Toni Reynaud03/02/2015 06:10:35
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423 forum posts
58 photos

Congratulations, Simon. That looks remarkably good once it's flying stably. Very scale appearance for something so small. Another masterpiece! Time travelling too - all done six years ago accoring to the date in the corner!

Toni

Edited By Toni Reynaud on 03/02/2015 06:11:32

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