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DH86 Refurbishment


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  • 4 weeks later...

Painting has been to a 2 steps forward, 1 step back rhythm. The silver and black cheat line went on ok except where it met the fuselage lettering. Too many junctions of paint masking caused bleed under the tapes and bits of the background to pull away. Much spotting with a tiny brush has more or less rescued it but I will think twice about a two colour cheat line through lettering next time.

 

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I quite liked the fin flash from the earlier scheme so thought that could be retained, but this time put the blue to the front as British aircraft used to have it. The swap to red at the front was prior to the start of the war but I couldn't find out quite when; seeing as the model can date from 1934 it could have had blue at the front!

 

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The Civil Air Ensign is a waterslide decal produced on clear craftycomputerpaper inkjet paper. The ensign is wholly appropriate being a British aircraft and I thought the colours matched the aircraft finish well. The ensign was designed quite simply using an Excel spreadsheet with a sourced Union Jack from the web.

 

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The design was then imported into Word to enable it to be scaled to an appropriate size

 

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Setting the printer to 'photo quality' produced nice intense colours......a small success.

 

The rudder and elevator closed loop cables have now been installed - a day and a half job feeding 6 cables through the fuselage and not getting them crossed in the process!

 

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The next job, when the weather allows, is to complete the painting of those parts of the cowls where they extend onto the fuselage and wings

 

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Thanks for the comments.

Mostly it seems it was military aircraft which displayed fin flashes. If you look at restored WW1 fighters and later examples such as an Avro Tutor, the blue is in front. The change could, I suppose, have occurred in the 20s as aircraft just as the Hawker Hind and Hart can be seen with red at the front. Its blue, white and red now for this example so I will happily listen for the gnashing teeth of the aficionados.     

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With painting complete its time to get on with the engines, tanks and undercarriage installation.

 

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The trousers completely enclose the inner engines so to allow for glow connection, a mini jack-socket is located just behind the cowl.

 

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With the cowl in place the male connector can access the female jack-socket.

 

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The one below is for the an outer engine, these are a bit more accessible so only needs a bracket to hold similar jack-sockets. The bracket then fits almost flush with the bottom of the cowl.

 

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In each case the glow plug connector part is a few turns of spiral wire with the lead soldered on and covering with heat shrink to take the load away from the solder joint.

I used to use the old nylon wire curtain rods as they were a good fit on the plug posts of a few years ago. With a standardisation for all my Lasers to using OS 4 stroke plugs, which have a wider than normal post, the wire that is used for a certain type of stationery file folder, is a pretty good fit.

 

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Buy a couple of these if you find them in a stationery shop and you'll be set up for years! With just one turn snapped over the plug, they are not going to let go very quickly. 

 

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Edited by John Rickett 102
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If I've done this correctly, the link should show the little engines singing in harmony! The engines had only been run for a few minutes prior to this so there is still some setting up to do, but run they do and much the better for being overhauled by Jon Harper.  The No:1 engine is really tight in the bore but even after this run it was loosening nicely.

 

https://youtu.be/NPNurI4riOw

 

 

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Thanks Graham, throttled back Lasers have a muted note, much less harsh than their contemporaries.

 

About 18 months ago I bought a new transmitter, (Futaba 16SX). The features blurb said it had a multi engine function but whatever that feature is, is not in the manual. I was hoping it would carry the throttle cut to any other channel which was designated a throttle…but it doesn’t.

In the end I got round the problem by assigning dual rates to each throttle channel, and only extending the range on one side. So now, pulling up the throttle cut switch, puts a high rate to each throttle servo and brings the throttle arms back just that bit further. I think I need to play with them a bit more to close the throttles completely - its all part of the pre-flight preparations.      

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Thanks for the support and the information Steve, yes that is what I wanted originally but being a novice at Youtube......

I won't be bringing it at the Easter weekend, the engines need to be set up which will take a while and then I'd rather do 2 or 3 test flights when there are few around.   

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Thankyou for all the supporting comments along the way.

Having stared at it for so long I'd almost forgotten the drab clothes it previously wore - hopefully its new bright finish will be an aid to my failing eyesight.

 

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I discovered yesterday during the engine runs that the magnets holding the tank covers for the outer engines were not up to the job; I think the old magnets will have to be cut out and replaced with stronger ones.

 

Another fault to be overcome is the lack of thread remaining on the crankshafts when using aluminium spinners. I believe Laser Engines recognised this oversight some years ago and made the crankshafts a bit longer on subsequent engines so its no longer a concern. Shaft extenders used to be available from Laser but aren't listed anymore so perhaps a call on Monday to Just Engines is required.        

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John,

 

I am sorry, but this sort of video should clearly be pay per view material! And there is me thinking Laser twins sound great.

 

Of course once you are happy with the set up, it would be great to let others know when you will allow the public to see it in the flesh.

 

Absolutely great work there and some really informative posts from yourself.

 

PS if you get stuck with prop adaptors PM me and I'll dig a path to the lathe for you.

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  • 4 weeks later...

Larger magnets have now been fitted to the (outer) tank hatches and spinner adapters, courtesy of Just Engines, have also been fitted.

 

A bit of time was spent at the field getting the engines to run in sync, a job made much easier nowadays with the aid of point adjustable curves for the servo outputs. Each engine has its own servo and servo channel from the receiver so its possible to use one engine as a reference and adjust the servo curves of the other 3 using the (9) point adjustments in the AFR settings -  I'm using a Futaba transmitter, though imagine that most comparable radios will have a similar facility though it might not be called Adjustable Function Rate (AFR).

     

Mixed fortunes on the first flight. Son Steve was pressed into service as the test pilot and did a splendid job, the good news is it flew with only minor trim adjustments required, the bad news (not really), a silicon exhaust coupler failed on the first circuit and the flight had to be terminated.

 

The inner engines each have a bendy pipe leading from the exhaust port to the homemade silencer. Short lengths of 1/2" silicon tube were used to make the couplings but the silicon cannot stand the exhaust heat for very long and one failed. This has happened a few times in the past and I haven't come up with an alternate solution, but one is needed as the fuel tanks are only millimetres above the exhaust pipes. When a silicon tube fails, the hot exhaust can be directed onto the bottom of a fuel tank and deform it.

I'll have to think of another method to connect the two parts together which will allow a degree of vibration protection and also not allow any of the silicon tube to come in direct contact with exhaust gases.

 

Fellow club member Mike Mennell takes excellent pictures of member's aircraft and lived up to his standard on Friday when these were taken.

         

MM WMFC1.jpg

MM WMFC2.jpg

Edited by John Rickett 102
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