EON Olympia 419

B Sharp · Post by **B Sharp** » 27 Jun 2021, 12:40

Hi Paul. I’m glad that John is not horrified by the amount of chopping that I am doing. I am desperate to respect the character of the model and Johns original work but I also want it safe to fly.

As to the dihedral, there is not a lot I can do about it without serious rebuilding of the centre section of both wings as well as the fuselage. I am not covering the wings until I have started on the fuselage in order to check the alignment and strength at that point.

Well, once again the wifey was right. The carefully shaped replacement skin and the internal structure of spars and ribs was coated with PVA glue and allowed to dry overnight. This morning I tacked the skin carefully into place before going over the whole thing with my covering iron set to 170 degrees C. The PVA melted together readily and I was left with a strong bond at all points of contact. I am very happy with the finished work and it looks much better than five or six large patches.

Brian.

B Sharp · Post by **B Sharp** » 29 Jun 2021, 12:37

The left wing is now almost complete and both wings are at the same stage. I am now waiting for the servos to arrive in order that I can complete the servo bays, which in turn will allow me to start on the aileron refurbishment.

Following Paul and John’s comments the other day I assembled the model this morning to assess how well it went together and whether it was all straight. Everything went as planned and it looks as though the tailplane is only a smidgen out of line. I balanced the airframe on its wingtips and bounced it around a little. There were no creaky or cracking noises so I figure it will be Ok in the air.
So Far, So Good!
Brian.

B Sharp · Post by **B Sharp** » 30 Jun 2021, 22:32

I have been doing a little work on the ailerons today, setting them up for new hinges. The plans show rounded leading edges set into the rear of the wing with “pin” hinges. However John has built the model with top surface hinges with mylar let in under the top skins and tape laid on top to seal the gap. I have cut all of this away and will replace with Kavan style nylon “pinned” hinges set in under the top skins.

I have also finished my work in the operating theatre and the pilot figure is looking a little happier after his plastic surgery. I now need a name for the little chappie.
I don’t know if John modelled the pilots face after himself, if so I would certainly call him John. However in the absence of that information I have decided to call him Oliver. So the whole project now becomes Olie’s Oly. ‘Simples’!!!
Brian.

B Sharp · Post by **B Sharp** » 05 Jul 2021, 13:09

Both wings are now at the same stage of completion. The servo mounts are now glued into each of the servo bays ready for the aileron servos to be set in place after the wing is painted.
I started on the covering of the right wing with Diacov and I have to say I am really enjoying using this material. I find I have to use a hotter iron than usual (150 degrees) but the material really works well. I have completed the right wing this morning and will tackle the left wing later this week.
Brian.

B Sharp · Post by **B Sharp** » 07 Jul 2021, 15:06

Both wings are now fully covered and tucked away on my wing racks until its paint time. The ailerons have been sanded back and have had their new control horns added.

Now the part that I have been looking forward to/dreading – the fuselage!
An extensive examination of the fuselage has exposed a number of structural problem areas and other features I just can’t live with.

There are a number of areas round about the centre of the fuselage at the wing seat which show extensive repairs in the past. There are numerous cracks and breaks which have been repaired with generous applications of epoxy. Inside the fuselage several of the formers have been damaged and have bits of wood glued over the breaks and there are bits where there is still movement in the structure. I will have to find ways to stabilise the structure and then repair the outer skin.

The rudder is actuated by a plastic snake. Now I hate plastic snakes with a vengeance and I have seen so many crashes caused by the slop that usual comes with this system. However I am stuck with it in this case as there is no other way I can get control from the cockpit to the fin. I will just have to live with it – thank goodness it is just the rudder affected.

The all moving tailplane (AMT) is actuated by a loooooong pushrod from the cockpit to the tailplane crank. The pushrod is made from ¼ dowel with long 2mm wire extensions to the metal clevises. This is slop free when the pushrod is pulled to give down elevator. However when it is pushed it bends enough to make be very nervous about its suitability. THIS WILL HAVE TO BE REPLACED!

I would like to install a length of larger diameter carbon tube, keeping the connections to the clevises very short for maximum stiffness. This is further complicated by a cross structure half way back to the tail designed to keep the existing pushrod from bending. We will just have to see how that all pans out.

I have made a start on stripping off all the existing paint so that I can better assess what is going on beneath the covering. MESSY JOB!!!

Brian.

Tom Pack · Post by **Tom Pack** » 07 Jul 2021, 15:45

Can you fit a carbon rod in place of the rudder plastic push rod? .070 carbon rod works great…..

Barry_Cole · Post by **Barry_Cole** » 07 Jul 2021, 15:57

Stay calm, you can do it..

BC

B Sharp · Post by **B Sharp** » 07 Jul 2021, 17:32

Tom, I will have a look at the possability of using carbon but the snake takes a couple of turns before it reaches the rudder horn.

Barry, you know me, I am always calmmmmm. (its the little blue pills that do it.)

Well, that was a bit of a surprise then!
I found that with the third coat of paint stripper the nylon covering was separating from the timber surface as the cellulose dope melted. I found that I could take an exposed corner and peal the nylon away taking the paint residue with it.
During this process the soggy nylon lifted an edge of the untreated nylon and I gave it a tug to see if it would come away. Low and behold the untreated nylon started to peal away from the fuselage leaving the original wood exposed. I was able to remove the nylon from the entire side of the model rather like skinning a rabbit.
If I can repeat this process on the other side of the fuselage it will save me a whole lot of messy effort with paint stripper.
Brian.

B Sharp · Post by **B Sharp** » 08 Jul 2021, 19:38

I got stuck right in about the fuselage today. It looks like this model has already had two lives as I came upon lots of red paint under the blue. A quick look at Johns notes showed me that he had all the details for BGA 1960 (DAL) a red and white 419.

Once I got the fuselage down to bare wood it became evident that this model had had a long and eventful life. There was considerable evidence of multiple repairs, even some of the repairs had repairs. However there was nothing that really frightened me and everything looked doable with a bit of care.

First of all I intended to remove the elevator pushrod which was causing me a bit of anxiety. I opened up an access hole at the back to get to the tailplane crank and the pushrod clevis. Surprise, surprise – there was no clevis! The pushrod was attached to the crank arm by a simple 90 deg bend in the 2mm wire rod. I don’t know if there was ever a fastening on the end of the wire but all that held it in place was a little side pressure against a former. I have two images attached below which show the wire ends of the 1.3 metre long dowel pushrod which caused me so much concern. The whole pushrod is to be replaced with a length of 8mm carbon fibre tube

I also think I have solved the problem with the plastic snake to the rudder. A carbon rod would not fit happily through the snake outer so that idea was abandoned. However I discovered that Bowden cable PTFE outer tube fitted perfectly inside the red snake outer. So I intend to install Bowden cable outer tube through the existing red snake outer and secured firmly at each end. The steel cable inner will pass through the double tube and be attached to clevises at each end. This should make a more secure control arrangement for the rudder.

However, before any of that takes place I will be looking to reinforce a number of formers to the rear of the cockpit where they have been cracked and split.

Brian.

B Sharp · Post by **B Sharp** » 11 Jul 2021, 15:46

The three main formers in the centre of the fuselage have all sustained breaks and cracks at the top, around the wing joiner assembly. I chiselled off as many of the epoxy runs as possible to get a smooth-ish surface (how often do you get the opportunity to use the word chisel when building a model). Referring to John’s fuselage plans I produced three reinforcing partial formers which were then glued and clamped in place to bridge all of the splits.

With the inside of the fuselage now pretty stable I turned to the outside of the fuselage. There were numerous holes, gashes and splits on each side. The holes were cut out and new balsa patched into place. The gashes and splits had thin cyano glue dribbled into them and held tightly till they had set hard. I then took a sanding block with 80 grit paper over the whole fuselage.

Peter B has been using Big Boy easy sand lightweight filler on his Oly 2B build and has recommended its use. As there was a fair bit of filling to be done on the fuselage I thought I would give it a go. A fair bit of filler had been used at the fuselage/fin and fuselage/tailskid junctures. John appears to have used a micro balloons mix but most of this came away with the nylon covering when it was removed. I tested the Big Boy filler on these areas first and was very pleased with the result. I have now started to give the whole front of the fuselage on the starboard side a thin coat of filler before I attack it with my sanding blocks.

I had been debating the best finish to apply to the fuselage once shaping was complete. John had used nylon and cellulose dope and I do have that in stock. However I have decided that I will cover the whole fuselage with 48gm/m2 glasscloth attached with laminating epoxy.

Brian.