Classic Aerobatic Model Photo Thread

[extra slim]

This is my good buddy Johns Tornado...really top notch job. It is fitted with a webra 61 with a dynamix and a pump. Sadly we struggled to get the engine running past the prime, so if anyone has any experience with pump or dynamix quirks (pump really), do's and donts, that may short cut the solution. Bypassing the pump is the favoured option, although if it can be solved with it, all the better.

[Terence Moore]

That is a great looking model, and eye-catching scheme. must have a lot of patience. Is it film or paint??

[terry westrop]

Hi there, finished very similar to the original I believe. Dynamix is a great 'sensible' carb & very easy to set.

Pumps, very rarely reliable in my experience however. I suspect it's a perry or maybe robart?

Dynamix will work fine on manifold pressure.

Ensure compression is good bearings are quiet.

[john featherstone 1]

the model is mine built from a plan, the pump is built into the backplate just in and out it might be dry as the motor has not been run for a long time or it could be goosed, the fuzz is light ply and balsa with foam wings and tail, its covered in film from hobbyking and most cut with a scalpel the words TORNADO and UKCAA were cut from film on a club members wifes machine? the electric retracts are from hobbyking also, weight about 7-8 pounds quess

[Martyn K]

It looks superb John - absolutely lovely

 

As an edited afterthought - is there anything you need to do to pumps to keep them healthy?

M

 

Edited By Martyn K on 09/05/2016 13:04:06

[Martin McIntosh]

Many years ago when I restarted the hobby I bought a job lot which included rear exhaust Webras, Dynamixes and Perry pumps. These pumps were notorious for not even working from new so old ones stand no chance as I found out. A TK regulator was used instead because the carbs. were designed, I think, to use with more than silencer pressure.

Good looking model. Do you reckon that the HK covering is polyester? I have only tried the `silver` which turned out to be aluminium and was reluctant to take paint (scale model).

[Martyn K]

Cheers Martin

What is a TK regulator?

Martyn

[john featherstone 1]

I have masses of solarfilm from the 70s and 80s a good friend of mine used to have a model shop and was a friend of I think mr solarfilm hence the large amount of film I have its manly seconds were the colour was a bit off or there was a fault in it and it was skipped and it came out of the skip , I have just covered a glider with some of it from the early eighties film that is I was give some of hobbykings film and found it very good so have stuck to that I find using film quicker than paint ect ect and easy to apply

[Martin McIntosh]

This is a fuel pressure regulator developed by Terry Cooper and distributed by Kieth Jones, hence the `TK`.

I witnessed a test of the prototype in Terry`s front garden and said that there would not be sufficient crankcase pressure developed for it to work but I was proved to be very wrong. The tank could be anywhere you wished and squeezing it as hard as you liked had no effect on the motor. The design was very simple with no adjustment possible or necessary. These were used for many years with the Kavan `pressure` carb. which had an enormous intake and would not work with a normally aspirated motor with just silencer pressure.

These enabled Terry and myself to use OPS Ursus, `Rizonanza` motors which were developed by us by re porting a standard 60 to give an extra 500 rpm+ and get two flights (without a landing in between) from one 12oz tank of fuel because the motor could be leaned out to the extreme. Many others at the time were running out of fuel with much larger tanks in a comp.

Continued in a bit.

[Martin McIntosh]

Having left the hobby for a while I met up with Clive Weller who had come into the possession of one of these previously owned by Mike Birch. I could not resist buying this and later got two more from the Nats swap meet for next to nothing. Yeehah! They are great with a Dynamix carb.

The main needle needs to be shut off way more than normal and some carbs., such the ST mag. may not allow this.

I do not wish to go into detail of the actual design save to say that the prototypes were made from two engine back plates bolted together with a diaphragm between them and a very simple and ingenious shut off valve.

[Martin McIntosh]

Here is a Pic.of one

[brian ball 1]

Hi Martin

l use one TK on a Rossi 60 with Kavan silencer it was brill with one of terrys Bulldog models

Rossi engine was very thirsty so it did help,

brian

[Giuseppe Ghisleri]

Jim Martin's Banshee

Almost ready to finish

3D printed NACA air inlet

[Jack Banner]

Congratulations Martyn,

re-assuring to get the maiden done and the plane down in one piece when it has been such a labour of love. I agree with Minty, 3 great looking planes there.

[eflightray]

From many moons ago, (no, not the sort you see when someone bent down to start a motor  }.

An original Orion fuselage and tail feathers given to me, and my own scratch built wing. The engine was probably an O.S. 60, the radio gear, an RCS Digi-3 converted to a 4 channel.

In the flight box was my MacGregor single channel Tx, modified for pulse proportional, must have been late 50's or early 60's.

 

 

Edited By eflightray on 11/05/2016 15:09:00

Edited By eflightray on 11/05/2016 15:09:41

[john featherstone 1]

took the motor out of the tornado today webra 61 pumped, the pump is an integral part of the back plate it is made by perry?? bit of tube on the inlet and blow through it all clear both ways so I took the back plate off no moving parts there is a black disc in the back plate dosnt seem to move if I try to push it how it works I don't know re assembled it all and come to put the motor back in the model put it in and tried blowing the tank up zilch coming out of the feed undid the motor and noticed the feed pipe kinked took the motor back out and turned the back plate round put the motor back in still kinked give up took the feed straight to the carb ill try that

[Martin McIntosh]

Some Webra bits I have left if anyone is interested. The piston and liner look to be in good condition with no scores. I could have sworn that I had more including a couple of Perry pumps but these are not to be found now. Being a bit of a hoarder this puzzles me. I have lots of Dynamix parts and have assembled two which are in use. The rest does not quite go together and looks like it may have been made in various cycle sheds since parts like the sliders do not mate up with the carb bodies. If you have one of these then I strongly advise against stripping it since aligning the spraybar is a nightmare. Cost you a fiver for postage if you want the basic motor.

[Stevem3akm]

Hello Martin, message sent. Regards Steve

[Colin Leighfield]

I've got a Webra 61 Speed rear induction which I bought many years ago and has had little use and a well-used but still good Speed 91, both with the Dynamix carb. Once you understood how to deal with the fact that the slow speed needle controlled fuel and not air, they were both easy to set up and ran perfectly. Used manifold pressure on the tank as per usual, but never needed a pump. Never heard of the TK pressure regulator, interesting stuff.

The Tornado looks brilliant.

[john featherstone 1]

flew the tornado yesterday (sunday15/5/2016 could not believe how well it flew retracts worked fine, asked by a club member after what the trim was like er not touched them I replied?? everything worked as it should well impressed

[Giuseppe Ghisleri]

Banshee

Aluminum to look for surface imperfections, later white and red to look at in the air.

[Giuseppe Ghisleri]

Here we are.

[Giuseppe Ghisleri]

Maidened today at 3600 gr overall weight .

She needed 250 gr of ballast in the nose.

Fast, handles very well side wind.

[Martyn K]

That looks fantastic. Congratulations on a successful maiden

[Masher]

Very nice looking model!