Round the pole

[Graham Slater 1]

Hamish thanks for the tip on the Ballards transformer on ebay i now only need to pick it up.

 

I now have one converted trainset transformer good for one plane on a 2 meter line.

 

i have one variable transformer good for one plane on up to 4 meter line.

 

i have one ballards transformer good for two planes on 4 meter lines or one on a 5 meter line.

 

2 poles 1 single and 1 twin, enough flying wire for all, 8 motors 5 sets of plans and enough balsa to build 5 planes.

 

Just add kids and wait for the havoc to begin.

[Peter Mack]

Simon,

What a wonderful model - and wonderfully complex with the contra-rotating props!  What are the specs of your model (span, weight, etc)?  Could it be converted to micro RC with different motor(s)? The MB5 was truly beautiful, just about the ultimate in piston-powered fighters.  Congratulations.

Peter

[Peter Mack]

Sorry Simon.  I have just reread your post and the specs are there.  I imagine that a lot of that 4.5 oz weight would be taken up with the motors.  Now, a 10 gram outrunner instead.....hmmm.  Or if you could still find this one at Hobby King (I can't) it would be nice:

http://www.rcgroups.com/forums/showthread.php?t=1118210&highlight=contra+rotating

 

Peter

[Simon Chaddock]

Hi Peter

In its current form it would be much to delicate & fragile (the motors themselves weigh 2oz) to fly outdoors.

 

It was the very gentle nature of control line RTP (the motor wires also act as elevator control lines) that allowed me to build and reasonably expect to fly this and similarly delicate models.

 

I am sure an RC version at say 24" span could be done for about 8oz but if my simple 20" 3.25oz 3ch is any thing to go by it would not be the easiest thing to fly.

 

Yes an interesting and rather expensive motor!

[gary davies-jones]

Looking at the setup in the nose of Simons lovely MB5 put me in mind of the motor and shaft setup you find in small contrarotating heli's. I wonder if it would be a cheap source of bits to build a contra-roting bird like the MB5 or Wyvern.

 

Just a thought

Gary

[Graham Slater 1]

Ooh I have found out today that the slot car controler works a treat but using the voltmeter i have found that the volts dont change so it must increase the amps.

 

I have set up the transformer and checked its output via the controler and pole with a 4551 motor. it almost took off out of my hand i think it will be very fast running.

[Peter Mack]

Simon,

You are probably familiar with the following, but anyway...  

http://www.rcgroups.com/forums/showthread.php?t=862222

Check Posts 4; 34; 63 and 65

Most of these terrific scale models are powered by a single 10 gram outrunner and weigh in at 100 grams or a bit over.  I do not have the skills or patience to build models like these but I have made several simpler models with these motors (or the smaller 5 grammer) around this weight and they all performed very well.  I have just checked the weight of a 10 gram motor plus suitable Esc, Rx, 3x servos and battery (2s 250 mah) and it comes to about 45 grams.

By anyway, enough dugression from RTP!  The following pics are from a very old booklet on RTP that I have a photocopy of.  Hope they are legible.

Peter

[Graham Slater 1]

Wahay I picked up my Ballards transformer and spare pole and motors. I cant wait to get on with it but the sqn dosnt parade until after new year.

 

Thanks Hamish for that tip I won a boot full of kit.

[Graham Slater 1]

If anyone wants an RTP transformer i have found another on Ebay 140499161088 I have enough already

[Jono]

Bit of a thread resurrection here I'm afraid!

Round the Pole Flying is no longer on the list of insured activities for the ATC, so we would need to get BMFA insurance in order to continue.

Has anyone done this? It seems a lot (~54 quid) a year to do this. I'm considering asking if they might do a special rate for RTP or indoor only membership.

Seems a backward step by the ATC of course, but we seem to be getting all our ducks in a line generally.

I guess my real question, is who is still doing this in the ATC?

[gary davies-jones]

Hi Jono,

we 215 City of Swansea are flying RTP. Got a feeling Llanelli are also still RTPing not sure about anyone else in the wing. Where are you based? Are you RTPing?

Fortunately we are a large squadron (over 120 on the books) and have reasonable resources for this sort of things. I do however agree that the price seems a little high. With two C.I.s as members we can supervise 8 cadets but that cost us over a ton.

During the Lees inspection last year we pulled our RTP demo for insurance reasons. One of the inspecting officers was not sure if we were insured as technically the aircraft is not flying as it is tethered and indirectly in contact with the ground. Interesting thought I know, however in this increasingly litigeous society we are taking no chances.

Gary

[Jono]

Hi Gary,

I'm over at 2499 in Berkshire.

We haven't done much RTP recently as I just haven't got round to it really. I now find that it's no longer on the list of insured stuff (along with ten pin bowling).

I'm a BMFA Country Member myself, but I don't really see the need for the BMFA insurance for RTP. Especailly as a Sqn of 40 odd cadets it is an occasional activity for us, mainly in the summer. (We use our Spooner Hut which means the main hall is out of commission to anything else).

I think I'm going to contact BMFA and see what their stance is. Will let you know.

Not sure why promoting an interest in aviation is so hard these days!

Cheers,

Jon

[gary davies-jones]

Hi Jon,

let us know how you get on, and perhaps we could have an interwing flyin/combat daysome time. PM me if you fancy a go at that.

Gary

(C.I. Davies-Jones)

[Simon Chaddock]

Jono

When I did school fete indoor displays I did eventually erect a 6' high fence around the circle, well actually just around the bit people stood around. A very light weight open mesh, the sort of thing fruit growers use to keep birds off.

I did it as much to keep people away (there was always somebody who wanted to see how close they could get!) than for their protection. It was covered by the school insurance (so the head told me!) but under the circumstances I felt a demonstration of "reasonable care" would not go amiss.

If the BFMA insurance covers conventional control line I would have thought electric RTP was very tame in comparison.

[Alan Cantwell]

i have a fair bit of RTP stuff, its on the list to be thrown out, never used it, it was part of a job lot i came by once upon a time, their are several scalextric type controllers, a yellow kiel kraft transformer thing, and whats left of a pole--the pole may take some finding though, but it only bearings and attachments, so not too bothered about it, if anyone wants it, just yell, collect only form oldham, lancs

[Cyclicscooby]

Well.. Never heard of RTP before this post, and i'm 40.. !!

My initial thoughts, were that it's like flying scalextrics.. A lesser cousin to control line.. Like a DIY cheapy plastic Mattel game from the 70's.. Whats the point in that today, when RC is so cheap... !?!?!

Then I started reading the replies, and realised it's alot more than that.. Building and experimenting at that early age obviously ignited the spark in many of you..

So, I take back my initial thoughts,and wish you the best with the cadets..

Luv

Chrisie.. xx

[gary walker 1]

wow i came across this forum looking for an "easy" way of introducing my nephews to rc planes as they love the cheap helicopters and it brought back memories of when i was a cub scout in the 80s in chichester

we had a leader called ken murch who being ex raf was nuts about planes even to the point of building a fullsize glider for the CCF at chichester high school for boys and yes it carried the pupils! i never saw the glider just photos of it unfortunaty

anyways he built his own version of RTP and can remember the hours of fun i had building the planes in the scout hut and flying them in the field my best memory was the model of a hercules ken built which included the ability to drop a bomb while flying? dunno the ins n outs of how he did it but would love to hear from anyone who remembers ken kenneth murch?

sorry for the long thread lol

[Robin Colbourne]

With all this lockdown of flying sites and being grounded at home due to Coronavirus, my thoughts have wandered back to electric Round the Pole.

Until earlier this month, the last time I flew RTP would have been in the 1980s at RAE Farnborough. Before that we flew in the Scout hut and on the lawn at home. I even remember my cousin from Canada buying a Harry Butler set from Ray Brown Models in Portsmouth, and flying in my gran's dining room, which couldn't have been more than about ten foot square.

At our club meeting, earlier this month, one of our members bought his set up along and flew several models including a KeilKraft Ercoupe with a geared motor, a Britten Norman Islander from an old Harry Butler kit, and a single rotor autogyro.

Eyeing up the current lawn at home, I reckon with a few plant pots being moved, I could fit a small circle in, although it may need hand launches unless I give the lawn a 'US marine recruit' haircut.

Does anyone else fancy having a go?  Please share your experiences old or new.

Here is the RTP Hut page. I'm awaiting a reply to establish if they are still trading and have stock, but its a good source of ideas and info nonetheless.

Electric Round The Pole - The RTP Hut

Edited By Robin Colbourne on 28/03/2020 14:19:19

[Robin Colbourne]

I've just had an email from Phil at the RTP Hut. He is very much still trading, and dispatching orders all the time the Royal Mail is still taking them.

He also added that he will be re-releasing the Harry Butler Pitts Special Kit and also has Gloster Gamecock prototype which has just flown.

[Cliff 1959]

I think it was at the Ally Pally Model Engineering Exhibition in the early 70's when I saw RTP, they had huge circle above the stands, I remember a Lancaster 'doing the rounds', it blew me away. I came away with a Harry Butler profile Spitfire which flew about 30 years later when I had a garden.

See my just-uploaded video for a sort of RTP Lol.

'Corona Lock-Down Microaces Combat'.

[i12fly]

If you use the Keil Kraft yellow transformer box as power source, make sure you put a fuse in the line to each output.

If you don't, when (not if) you get a short on the electric lines it will blow the transformer windings. Can't remember what size fuse I used but it was appropriate for the motor draw.

[Andy Stephenson]

A while ago I designed a simple electronic RTP controller that used a resettable over current trip...

[Robin Colbourne]

Andy, Thank you for posting your power supply circuit diagram. Three questions:

1. At risk of appearing totally thick! Do the hand controllers go in line on the motor outputs shown?

2. Can you use standard Scalextric hand controllers with this speed controller?

3. How do you vary the input voltage to suit differences in line length?

[Phil Green]

As teens we used to do a lot of club slot-car racing and one of the competitions I came up with was racing two cars per slot, and I was thinking the principle might be useful for RTP scale functions like swing-wings, retracts, bombs etc instead of a third wire.

We fed the controllers with AC, and for each slot, one of the two cars would have a diode in series one way, and the other car with the diode reversed, then a 100uF cap across the motor. The two controllers for that slot also had opposing diodes, so one car ran on positive half of the AC and the other on the negative half, giving completely independent control of the two cars through the same slot.

We ran two or four slots, ie 4 or 8 cars, which would start exactly half a lap apart and the aim was to catch and nudge the other car. It was brilliant fun with 4 cars, hilarious with 8.

Its not directly relevant to the topic but maybe a similar system could be used for auxiliary RTP functions?

Cheers
Phil

Edited By Phil Green on 29/03/2020 17:14:33

[Dale Bradly]

Posted by Phil Green on 29/03/2020 02:30:05:

We fed the controllers with AC, and for each slot, one of the two cars would have a diode in series one way, and the other car with the diode reversed, then a 100uF cap across the motor. The two controllers for that slot also had opposing diodes, so one car ran on positive half of the AC and the other on the negative half, giving completely independent control of the two cars through the same slot.

That is a brilliant idea! So simple, but effective.