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John Slater Airspeed Tern

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Barry Apostolou
Posts: 43
Joined: 07 Jun 2019, 15:36
Location: Surrey

Re: John Slater Airspeed Tern

Post by Barry Apostolou »

Hi, Tern Watchers,

The wings are now painted and drying off. As you will know I did not use ply for the leading edges of the wing. This was mainly due to weight saving and cost and also I had loads of balsa sheets looking for a home. Accordingly I wanted to try and paint the leading edges to mimic ply, this 'Faux' type of painting was a popular decorating skill in recent years, involving 'rag rolling', 'dragging', 'scumble glazing', 'marbling' etc. All being techniques using paint to mimic wood, marble or other surfaces. A good buddy of mine is a sign writer who helped me with this effect. It is applied using a brush to drag across the covered surface to mimic the wood grain, and is just a mixture of Satin Varnish and paint to get the colour you want.

You can buy staining varnishes from B&Q and they do an 'Antique Pine' (Small pot £5.99) which is very like the color of varnished ply. The method is this:-

1) Mask the area for painting using good quality masking tape. This will determine the edge you get. You can use a stick on 'cheat line' in Orafilm to cover the join between the varnish and covering if the join line is too untidy

2) Ensure the surface is free from dust and other stuff found in work shops. I use a large soft brush for this. Also try and get some additional heat in the work shop to help with the flow of the varnish. Otherwise if too cold it gets 'sticky' and does not flow well across the covering. To give an idea of the colored varnish, it looked like clear honey. If you are adding colour make sure you have thoroughly mixed it all up, to prevent color changes during application.

3) Use a 1 inch soft brush to paint on the varnish with positive strokes going from root to tip. Remember each coat used will make the finish darker so you need to be bold and try to get coverage with the initial strokes, do not reload the brush for the same area. Do not paint into the masking paper too vigorously as this may cause the varnish to bleed where you do not want it.

5) When you have painted the whole area take another clean brush, moistened with white spirit and gently stroke it across the entire surface, again from root to tip. this will give the impression of wood grain. Before it gets any drier take off all the masking tape. This removal needs to be 'bold' and pulled away from the painted surface.

6) Having done this the best you can; leave it alone. do not try to 'over work' the varnish. You need to just go away and let it harden for 24-48 hours. Until it is dry and cured you will not improve the final outcome, I know this from bitter experience. Where I have tried to make things better and simply messed them up more.

A day or so later you can inspect the finish to see if you are happy with it, or if you feel it would be better/neater with a 'Cheat line'.

Well that is it for now, my own outcome as you can see on the picture was OK, not perfect by any means.

No doubt loads of people will point this out on the hill. However, as a builder of many vintage sailplanes I do have the perfect answer to this. It is

"When you do yours I am certain it will be perfect, mine was the best I could do at the time." (Tee, Hee )

Just the balancing and the maiden flight now to do now.

All the best

Barry
Attachments
IMG_303 Stained wing.JPG
Last edited by Barry Apostolou on 30 Jan 2020, 09:43, edited 7 times in total.

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VinceC
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Re: John Slater Airspeed Tern

Post by VinceC »

Lovely covering

Adam C
Posts: 16
Joined: 26 Oct 2017, 14:36
Location: Southampton

Re: John Slater Airspeed Tern

Post by Adam C »

Clever idea.. Not just a pretty face then.

No chance of a faux marble airbrake then?

Barry Apostolou
Posts: 43
Joined: 07 Jun 2019, 15:36
Location: Surrey

Re: John Slater Airspeed Tern

Post by Barry Apostolou »

Good idea, I am certain then that some one would say........ " Marble ?? That's too heavy" :)

ATB Barry

Barry Apostolou
Posts: 43
Joined: 07 Jun 2019, 15:36
Location: Surrey

Re: John Slater Airspeed Tern

Post by Barry Apostolou »

Hi Tern Watchers

Belated New years Eve wishes to all. It has been a busy time over the holiday period. With lots to do and the odd health issue. Also I appear to have been the victim of an on line 'trick/scam'. I ordered and paid for a model that was never sent, the guy that did it vanished off the 'Messenger' page' where we 'spoke', and is not responding to phone calls.

So if some one offers a Flair Sunrise gilder on line be very cautious. I suppose I was a bit naive and lost out to the tune of £100.00. Still we live and learn. I am not mentioning the guys name as I understand this is not allowed. It is a shame because he seemed like a nice chap. I am more disappointed than annoyed.

Moving on to more pleasant things, my Fair K8 and Chris Williams 1/4 scale T21 have both been flown and went really well. Now back to the John Slater Tern. The final rigging has been done and the ballast weight added to get to the specified COG. Like most vintage gliders a fair bit of lead was needed to do this, 9.00 ounces to be exact, as you may recall the under sheeting at the front was not finished to allow me to do this. So in this gap went the lead, or least 7.00 ounces of it. Two ounces were left as 'trimming weight'' to be added at the front of the cockpit so that after the test flight and dive test I could go either way with the COG depending on the out come of the test.

If you plan to build this model please make sure you keep the back end as light as possible, the all up weight has come out at 11 lb 6 oz, I don't think that is too bad (?). But with out care during the build it could have easily made 12-13 lbs. The areas to work on here are obviously all the bits at the back (rudder, elevator, fin), however the selection of material remains important, for example 0.4 mm/0.6 mm ply were used at the back and 0.8 mm was used at the front end for sheeting the fuselage. Ply was not used on the wing sheeting, I went for balsa painted to look like ply. The front wing joiner is 10 mm steel and the rear 8 mm. The nuts and bolts holding the wing joiner boxes in the fuselage were replaced with cover pieces of 2 mm ply. This saved precious weight over all. It is never one thing that saves the weight but little bits all the way through the build that do it.

The final sheeting was then added and stained to match the rest of it. I enclose a picture of this. So all that remain now is the test flight, I will keep you posted on the outcome.
All the best Barry
Attachments
Tern final Bottom Sheeting.JPG
Tern final Bottom Sheeting.JPG (20.53 KiB) Viewed 479 times
Last edited by Barry Apostolou on 12 Jan 2020, 16:26, edited 12 times in total.

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VinceC
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Re: John Slater Airspeed Tern

Post by VinceC »

Thus is a very informative build log, thanks John. I see you gave the Tern decal on the side, any chance of sharing it so it can be added to the web page?

Barry Apostolou
Posts: 43
Joined: 07 Jun 2019, 15:36
Location: Surrey

Re: John Slater Airspeed Tern

Post by Barry Apostolou »

Hi Vince,

It is Barry Apostolou here, I am not John Slater, I am simply building his plan of the Tern, and trying to do the build log as best I can.

I will see if I can find the Tern logo and put it on line for you. It was one I lifted from the internet and used decal paper to print it off and get a water slide decal.

All the best

Barry
Last edited by Barry Apostolou on 12 Jan 2020, 16:18, edited 3 times in total.

Barry Apostolou
Posts: 43
Joined: 07 Jun 2019, 15:36
Location: Surrey

Re: John Slater Airspeed Tern

Post by Barry Apostolou »

Hi Vince,

I think I have managed to find those decals and attach the file below. The decal paper can be accessed on line. If you use an inkjet printer you have to spray the decals with a clear lacquer to water proof the inks. A laser jet printer does not need this. Then you can just float off the decals in warm water and apply them. Finally the decals are sprayed over with a clear lacquer to 'lock them in'. With the lacquer/Varnish it is best to use Matt or Satin, as gloss makes the decals too shiny, and they show the edges.

All the best

Barry
Attachments
Barry Tern Decals.docx
(42.16 KiB) Downloaded 52 times
Last edited by Barry Apostolou on 14 Jan 2020, 08:43, edited 4 times in total.

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VinceC
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Re: John Slater Airspeed Tern

Post by VinceC »

Very nice Barry, thanks

john slater
Posts: 57
Joined: 24 Mar 2015, 07:29
Location: Dudley , West Midlands

Re: John Slater Airspeed Tern

Post by john slater »

Hi All,
On my original I used ` Letter Stencils ' and sprayed a clear varnish over to seal.

John

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