Indoor electric control line.
 

A long time ago (like over 50 years!) I needed a system that would allow me to fly planes when I wanted and insulated from the vagaries of the English weather.
I had built some 'round the pole' planes but with mixed success due to rather short lines coupled with heavy low power brushed motors.
I felt sure a bit of 'elevator' control would improve the chances of realistic flight.
You have to have two wires to carry the current so why not use them as conventional control lines wires as well so i set about designing a central 'pylon' that not only conducted the current but gave differential movement controlled by a 'stick' from out side the circle.

As I didn't live in a baronial hall this feature was vital as the biggest clearance circle I could achieve in my parents house was just over 14 ft diameter. This meant flying on 6ft lines. Good for keeping voltage drop at bay but resulting in a rotational speed far beyond what a human could handle from the centre.
So small very light planes it had to be which suited me fine.

The combination of good throttle control, elevators and a smooth floor meant even delicate planes had a reasonably long life, in fact it was quite hard to build light enough to make full use these characteristics.
Being so long ago I don't have many pictures of them but typical is this converted Keil Kraft rubber scale series Fairey Gannet.
http://www.rcuniverse.com/forum/atta...mentid=1995054
The very benign flying conditions allows scale diameter wheels and a hand carved 'inserted blade' prop in balsa wood.
Or this free lance 4 motor not unlike a B24 Liberator.
http://www.rcuniverse.com/forum/atta...mentid=1995055
Still stick and tissue it even has telescopic sprung undercarriage (springs from retractable ball pens!). Impressive in flight but it has to be stored carefully as each motor weighs more than the entire airframe!
This twin actually has a third line used to power a motor to work the flaps and the loading ramp.
http://www.rcuniverse.com/forum/atta...mentid=1995056
The interior could hold a dummy stick and tissue house brick.
http://www.rcuniverse.com/forum/atta...mentid=1995057
Which it could drop it in flight!

As my building skills improved I moved onto true scale not only in profile but in construction as well like this Sopwith Pup.
http://www.rcuniverse.com/forum/atta...mentid=1995058
This had the benefit of a geared 'slot car' motor so it could drive a scale diameter (and pitch) carved balsa prop.
The undercarriage used elastic cotton to give scale springing and very fine steel wire for the load carrying rigging.
One advantage in having a very skilled model engineer for a dad meant he spun a scale aluminium cowl for me!
http://www.rcuniverse.com/forum/atta...mentid=1995059
At 18" Span the Pup weighed just 2oz complete.
I seemed to remember it flew rather like the original - very well but stall it at your peril!

The next plane would have to have thicker wings........

The story continues.
A contemporary of the Pup was the structurally interesting Fokker Triplane.
With the experience of building the Pup I could really go to town on the scale features even down to using 1mm round balsa to emulate the fuselage steel tubing.
This is the only picture I have taken during construction.
http://www.rcuniverse.com/forum/atta...mentid=1995167
The fuselage is correctly internally braced with cotton thread.
Built to the same scale as the Pup it has a 16" span.
http://www.rcuniverse.com/forum/atta...mentid=1995169
My dad again provided the spun aluminium cowl. It uses the same geared slot car type motor driving a scale prop but this time is has a scale Oberursel that goes round with it inside the cowl.
http://www.rcuniverse.com/forum/atta...mentid=1995170
The final touch is the controls. They are all correctly run back to stick in the cockpit but of course all but the elevator are locked off.
http://www.rcuniverse.com/forum/atta...mentid=1995173
The control line bell crank just has a short link to the stick. The scale control runs actually move the elevator.
It flies very well indeed and is able to 'hang on its prop' at a high angle of attack just like the original.
Surprisingly robust I still have it despite now being over 45 years old.
Now in well earned retirement but it still runs.
http://vimeo.com/44119024 What next bearing in mind I was still on very short lines. I needed to model a plane that had a big propeller and a short wing span.......

Clawing at the ground ready to go fly. Nice.

The final chapter
A plane with a big prop and small wings, then I remembered this, the Martin Baker MB5.
http://www.rcuniverse.com/forum/atta...mentid=1995456
it had been described in the Aero Modeller with a nice 3 view. Fairly well known now but in the early sixties not many people had even head of it.
I guessed a 22" span was about the maximum I could handle but this still gave in effect two 3 blade 8" diameter props!
To look right this could not be stick and tissue (except the rudder and elevator which were fabric covered on the prototype) but had to be all sheet covered.
To keep weight to an absolute minimum it was built as a stressed skin monocoque using 1/32 balsa sheet planks.
http://www.rcuniverse.com/forum/atta...mentid=1995457
Even the formers were 'built up' using the same material.
http://www.rcuniverse.com/forum/atta...mentid=1995458
It would not look right without its contra rotating props so it ended up with two 'slot car' motors geared onto coaxial shafts.
http://www.rcuniverse.com/forum/atta...mentid=1995459
The prop and spinner is all balsa.
The canopy was home moulded and the cockpit fully finished with all the instruments.
http://www.rcuniverse.com/forum/atta...mentid=1995460
I don't 'do' pilots in any of my planes so the harness straps are neatly folded on the seat. ;)
Completed.
http://www.rcuniverse.com/forum/atta...mentid=1995461
In view of its very light weight construction the undercarriage has working telescoping suspension to reduce landing shocks.
It weighs 4.25oz and produces just about that much thrust.
It flies well and compared to my other models is quite fast - actually only about 10mph but on 8' lines it feels much quicker! Landing is the most stressful part trying to keep all those balsa blades from touching the ground.
The hollow stressed skin structure acts as a wonderful sounding board so the gear wine is greatly amplified making it sound like a turbo prop, as this ground run shows. It was securely tied to a lump of lead!
http://vimeo.com/44119026 It is now 45 years old!
At this point I started my career and like others before and since aero-modelling had to take a back seat for many, many years.

That MB5 is a beauty, first saw it on RCG(a post by Peter Mack) which led me to RCM&E:
http://www.rcgroups.com/forums/showp...9&postcount=11
http://www.modelflying.co.uk/forums/...p?th=34517&p=1
I did experiment with RTP but not with such scale wonder,instead of using power down the line I use on-board small Lipo,micro Rx and one micro servo for elevator.

I'm not familiar with how links and photos work in this forum - apologies in advance.

Below are two pics and a video, or at least some links, to an Electric Baby Pathfinder flown by Larry Renger at local events. It is a VERY nice result.

= = = = =

https://flic.kr/p/cucziW


<a href="https://www.flickr.com/photos/star-paul-star/7539044620" title="IMG_2496 by Paul Wescott, on Flickr"><img src="https://farm8.staticflickr.com/7138/7539044620_3afc4129ef_s.jpg" width="75" height="75" alt="IMG_2496"></a>

= = = = =


https://flic.kr/p/cucYps


<a href="https://www.flickr.com/photos/star-paul-star/7539122312" title="IMG_2590 by Paul Wescott, on Flickr"><img src="https://farm9.staticflickr.com/8014/7539122312_99a6613e21_s.jpg" width="75" height="75" alt="IMG_2590"></a>

= = = = =


Larry Renger (has a little bit of experience) flying the Electric Baby Pathfinder in the Tustin Blimp Hangar


http://www.youtube.com/watch?v=SYn5g5OcPgE&sns=em

= = = = =

My entire photo collection:
https://www.flickr.com/photos/star-p...7626915164120/

= = = = =

Let me know if you like them!

Paul

I like them. Didn't know there were that many control line planes left in the world. You have thousands of pics there.

Thank you for the post aspeed. The Knights of the Round Circle (Anaheim, CA centered) and the Valley Circle Burners (Van Nuys, CA centered) are both small clubs, but very active. There is usually a LOT of eye-candy at the sponsored contests and I try to get good pics for those who can't attend in person.

Paul