Oh well, one can’t have everything work out in life! Maybe God wants to keep us on our toes?!

I am already faced with changing the foam nosewheels for soft rubber (if I can find them) to stand any chance of keeping the nose on the ground and not being swung into wind by every gust of wind and I am expecting to have to add a fair lump of extra nose weight to balance the model for flight anyway.

Interesting that TonyT asserts that the BAa146 has servo tab operated elevators and scrooge that those Convairs also used the system (for unspecified surface) and Baz that the Brittania had servo tab on the ailerons and that he has seen a plane with servo tab equipped rudder taxying downwind. I assume this was on film/video. All of this is food for further study so thank you gents.
I have also just noticed that wieesso’s post says that trim changes from operating the flaps of the Caribou were ‘largely taken out by automatic movement of the tailplane’… not the elevator as I might have expected. This would, I assume, be the raising of the leading edge to give the tailplane assembly the inverted camber more appropriate for low-speed flight as well as the intended change in angle of attack.

All interesting stuff!
Robin

Thank you Martin for your response and the link from which you quoted.
I was beginning to suspect that the Caribou’s systems were interlinked as I had noticed that the flap deflection was affected by the ailerons’ movement, but did not suspect how much.
The direct link between rudder and aileron to produce co-ordinated turns from either is what I had long intended to do via one of only two mixes available on my transmitter, but this is affected by whatever I discovered in the relationship between flap and elevator in pitch change. I have a bit of thinking to do to achieve the automatic trimming out of pitch change due to lowering the flaps. This for other models has normally taken the other mix, but it would be better to do it aerodynamically than by a percentage mix.
I assume that the term ‘spring tab operated’ means that the elevators are not directly controllled by the pilot’s stick input but that this goes to the tab which is sprung to take care of momentary variations in load due to airflow. This is a surprise to me as it was what I had hoped to find in relation to the rudder – which it seems, contrary to my expectation is directly powered but with a balance tab to take some (most?) of the load off the pilot.

As the elevator is a far more vital control than the rudder for a model flyer, once off the ground at least, this is quite a challenge. This proposition is likely to make RC pilots very nervous as we are not used on the whole to using any tabs at all on our control surfaces. I have been using balance tabs on all my main controls for a few years in order to allow for the use of the cheaper servos even on larger models, but the next step is to actually fly a model equipped with a servo tab in order to gain experience – and the confidence to use such a system for such as elevator.

My primary reason for enquiry was the high probability of side gusts while taxying overcoming the nosewheel’s adhesion to the ground and weather-cocking the model because of the size of the fin and rudder.
I think that what I may have to do is accept that my elevators will be conventionally powered and the rudder indirectly (by the linking of both tabs into one servo tab) in order to find out how effective this is. Perhaps later, if successful, I might then be comfortable with indirectly powered elevators.
Any further input on this will be gratefully recieved!

Robin

Haha! … Does that reflect on the Aussie pilot’s sensitivity in the posterior, his macho attitude, or his honesty in reporting Macca?
Or maybe the CO’s opinion on the reliability of any or all of the above?

I now have this vision in mind of the mess full of hobbling pilots with impacted spines shrugging off their injuries with the landing strip littered with bits of angle iron!

Thanks Mike.

I don’t see ‘Caribou’ on their exhibit list but I may give them a try.
I am aware that the Queensland Air Museum have taken one of the ex-RAAF aircraft – there are photos on their website. The undercarriage has apparently been replaced with a jury rig.
Before contacting them direct I thought I would try here first as being the sort of place members of different museums might visit regularly.

Using Google search I have been a bit surprised not to see a book coming up so maybe there is not one around to refer to anyway.

Robin