Member postings for Chris Barlow

Thanks Phil. I have used 2D cad programs for Architectural plans for work but that was Autocad R14 from the 1990's! Once I stopped trying to use Fusion 360 like Autocad I started to make some decent headway! Always up for learning new skills whilst I'm still young!

Andy, Sorry! Busted!

Edited By Chris Barlow on 16/03/2020 15:24:26

Excellent idea Dirk. I'm sure there'll be plenty of SAR volunteers to pick up the pilot!

I did try to release a secret agent parachutist from my Vulcan bomb bay but even though he jumped from quite a distance from the slope face, due to the slope lift he cleared us at quite a good height and made his way off to invade the pier on the other side of the Orme!

I remember the days when a pilot bust, shoulders up, was good enough for scale! What has happened to us!

Your pilot as drawn on the plan reminds me of the old Dolly peg dolls!

Time for some bench flying soon Chris?

I wonder sometimes whether the additional weight of glue negates the weight saving of not using solid, soft balsa? Decisions, decisions!

How are you finding the peel ply Rob? The Sabre was the first model I've used it on and have found it leaves a very nice finish, plus it's oddly satisfying to peel off!

Hmmm, I was going to start with "not much progress over the last few weeks" but looking at the last photos I realise there's quite a bit of work been done, just doesn't seem like it!

All the parts have been sanded, glassed and sanded again. I spent quite a few hours attempting to design my own pilot seat in Fusion 360, which required not only studying photographs of the seat but also learning how to draw! I think I'm happy with the end result though and have also discovered that drawing is one thing but drawing so that the model can be 3D printed takes a little more thought!

Pilot was a free model from Thingiverse.

A slightly gentler learning curve has been a move from my usual paints to a 2 pack paint, something I've never used before. Although not much more expensive than cellulose paints this lot cost nearly £140, but th primer will do all the models I'll build this year and the 3 colours are enough for 2 of my current builds.

What did surprise me though was the cost and availability of filters for my respirator. I usually treat myself to the filters through work but my usual sources were out of stock and worryingly the message on the Screwfix pages limited supply of respirators and filters to 5 per order! Further online searches finally revealed a supplier near London with 1 pair left in stock so that was ordered. There were others available on ebay but the usual price of around £30 had increased to £45 with one seller advertising the filters at a whopping £99!

So with new filters fitted and between gaps in the rain the glassed parts were primed, sanded and primed again.

A few extra parts there for a JP too!

I also printed off a few painters pyramids to help in drying the parts.

The wing has also been primed but I ran out of space to photograph it!

Photo says it all!

Lets go!

Hi Rob.

Yes the rudder actuation is a tough one if you want to keep the hinge lines and don't want external snakes or pulls. You could always "adjust" the hinge line 1/4" forward and/or offset the elevator bell crank to one side as I've seen on a couple of blogs.

Depends who notices!

Andy is already scouring the blogs looking for sinners and heathens!

Thanks Chris. I managed to stop myself from unwrapping it earlier by chopping down the neighbors conifer trees which have started to rub against the shed roof. He's in for such a surprise when he comes home!

I also had a bit of an epiphany regarding mixing ratios. I usually use Zpoxy which is a 1:1 mix ratio but have now changed to Easy Composites laminating resin which is 100:30 resin to hardener. The voices in my head were arguing how to calculate the required amounts to mix 20g of resin when a quiet, rational voice from somewhere behind my forehead explained for 20g resin divide by the sum of the ratio, multiplied by the resin amount. The balance up to 20g is hardner!

so, 20g mix / (100 resin + 30 hardener) = 0.1538

0.1538 *100 resin = 15.38g resin

balance to 20g = 4.62g hardener

To be certain I tracked down an epoxy resin calculator online and checked the amounts for a 100:30 ratio.

I don't know why this has confused me before as it seems so simple now!

Edited By Chris Barlow on 01/02/2020 19:36:22

The Sabre fuselage is quite sleek Chris so I wouldn't worry about it getting a little "fat"

Maybe it's called a Dog because it has a wet nose?

Keep going, we're nearly half way there!

Getting close to paint and details now. This is where the time goes though!

Impatience got the better of me and I couldn't wait a full 24 hours for the resin to cure so after approximately 20 hours cure time I have removed the peel ply.

It came off relatively easily, pulling the ply at 180 degrees to the surface with a consistent, moderate force. Fortunately it didn't peel the wing skins off at the same time!

The finish is very flat and has filled in the cloth weave nicely. There is a slight texture left by the peel ply which does give it a slightly rough feel but I expect this will sand off very easily.

Overall I'm very impressed with the finish and will definately be using peel ply again on the JP, U-2 and Meteor wings.

The way I understand it, which may not be completely correct, is the peel ply is polyester to which the epoxy resin does not stick to very well, at least not as well as the glass cloth. when the glass cloth is wetted out with resin the peel ply is laid over it and squeegeed down. Any excess resin is wicked into the peel ply weave leaving the bare minimum which is trapped like the inside of a mold to fill the weave of the glass cloth.

When cured the peel ply is "peeled" off the glass cloth, which is possible due to the epoxy not sticking to polyester very well, leaving the glass cloth adequately "filled" requiring only primer and sanding before paint.

There are a few good videos on youtube showing the process including some by Danny Fenton. The goal is to achieve a better and lighter finish than a 2 coat resin technique with less effort. Win/Win (if it works)

That's a very clever and neat solution to the problem of flaps and ailerons with central servos! I might have to try that on something.

Well, what a disappointment!

I've been very busy at work this week and as it usually happens when you're busy time flies. In fact somehow I have lost a day thinking today was Thursday. I had planned to get in the shed by 6pm and get the top half of the Sabre wing glassed having spent most of the week glassing everything else, including a Jet Provost.

Unfortunately today isn't Thursday. It's Friday, and at 9pm I realised this. Friday night is indoor flying night from 8pm till 10pm, something I look forward to even more now my club field is muddy and inaccessable and the weather is pants! Flying with a different breed of loonies and comedians from the PSSA guys on Fridays is always a good laugh.

And now I've missed it!

Still, I have made a little more progress on the Sabre over the last week with parts being glass clothed. The last part of the airframe was the top of the wing and since it is quite a clear area I had decided to try using peel ply over the glass cloth for the first time. I usually blot and scrape all the resin off the cloth, let it cure then spread another resin coat over it with a card and finish with sanding and primer...and more sanding, and more primer...

I have wanted to try peel ply for a while as it is supposed to eliminate the second resin coat and the sanding required so with a refresher course of youtube videos when I got home I rushed out to the shed to give it a go, and missed the flying!

So I now have a stripey wing and will have to wait to see if I have messed it up or not!

And a couple of fuselages basking in a warm shed curing!

Yes, there is a "smudge" of filler on the JP's back where my 1/8" balsa went flat instead of curved!

If it's any help I drilled the holes for the forward (pivoting) wire oversize to allow the pre bent wire and bush to pass through over the bend. The wire and bend fits through the hole in the bell crank without the bush, and out through the other side, as the bush is pushed into the bell crank. The oversized hole also helps in getting the wire accurately perpendicular to the fuselage.

Once centralised and in position the bush was glued to the tail plane fairings with epoxy and micro balloons. Mine is slightly different in that I made my own bell crank and I have used a PTFE bush instead of a brass tube but I think the principle is still the same?

Once glassed I was going to glue the wire joiners into the tail plane halves with epoxy but I think I'll use a dab of Uhu instead as this will secure them in place but will allow easier removal in the event of any damage. (similar to the pritt-stick idea)

I too tight for cheques!

Slopeside beer tokens?

Yep I can do that if it's OK with Andy.

I have already sent Martin and Gordon a copy of the DXF files for them modify and produce a PDF plan from so that may be appearing soon?

If anyone would like a copy of the sliced plans please PM me.

I always said you were odd Gordon!

A couple of drop tanks built in balsa from Andy Meads 3D drawing. More details in my build blog.

Thanks Phil/Chris

Yes the drop tests went fine. I also set the win at an upward angle of about 30 degrees to see if the clevis would jam if the tank came off at an angle but that was fine too.

I was thinking of a hemispherical dome on the tank fitting into a concave recess in the pylon for the ant rotation, or maybe just a very short 3mm pin? There is also the tank brace which I intend to fix to the tank and clip to the wing with a single magnet and steel washer. Dont want that too strong and prevent the tank from dropping.