Slingsby Petrel 3.4 metre designed by Chris Williams

[MikeQ]

Hi

 

looking good.  Re printing on glossy photo paper.  Just in case anyone might find it useful if they don’t have a suitable printer.  You can take images (dials, instrument panels, etc) on a memory stick to Boots and print them out on photo paper for less than a quid I seem to remember.  
 

mike

Edited December 21, 2022 by MikeQ

[Peter Garsden]

When I assembled my pilot he was a few mm too wide so I have to shave some width off his shoulders. His head and arms were separate so making the job easier. I sanded down each shoulder to size then cut a piece of 1/64" ply over the hole for the arms to glue to. I then filled the holes where I had cut away with Milliput which worked a treat.

 

[Peter Garsden]

Will paint the chap over Christmas, that is the plan.

 

 

Next job is the towline attachment. First a 10mm hole through the nose.

 

 

This is the multiplex attachment which fits into the hole. One has to fix a 1.3mm rod inside an outer. The rod protrudes 3mm beyond the bar and takes the loop of the towline. When the bar is retracted the loop and the towline comes off- very clever and efficient.

 

 

This is a SLEC closed loop outer left over

 

[Peter Garsden]

 

Canopy cut to size and glued on using canopy glue which will go translucent when it dries. I find the clear tape the best with the fibreglass reinforcement.

[GrumpyGnome]

2 hours ago, Peter Garsden said:

When I assembled my pilot he was a few mm too wide so I have to shave some width off his shoulders. His head and arms were separate so making the job easier. I sanded down each shoulder to size then cut a piece of 1/64" ply over the hole for the arms to glue to. I then filled the holes where I had cut away with Milliput which worked a treat.

 

Interesting pose!  I suspect it looks better when he's in place......

[Peter Garsden]

Yes I know it looks idiotic but his arm wouldn't fit the space unless it was pointing up in the air, so that's how it is going to be. I can highly recommend the work of Andrew Meade who sells 3D pilots on Ebay at reasonable prices by the way. In fairness I didn't send him dimensions on order because the fuselage wasn't built then.

 

I guess Derek is pointing at an eagle thermal soaring above him in shock and awe, and when on the ground is telling the toe line man that he is suffering from terrible cramp with his knees jammed under the centre console?

 

And the other news is that I have decided to cover the fuselage in 25gm cloth and resin rather than Oratex. This was how I finished my Spitfire and was very pleased with the result. I am going to use Peel Ply, and then a mix of water based resin, lightweight filler, talcum powder, and acrylic paint to fill the weave. It is not the way Chris Williams does it but, I think will work out a bit lighter. We will see.

Edited December 23, 2022 by Peter Garsden

[MikeQ]

Hi Peter

 

if you use peel ply you wont have much weave to fill if any.  Don’t skimp on the finishing resin, you need to wet out both the cloth and peel ply.  Ive had poor results with ‘modeling’ glass cloth from say Deluxe which has a kind of startchy fixing applied to help make it easier to handle.  Resin doesn’t penetrate properly and leaves pin holes more easily in my experience.  East Coast Supplies up in SouthShields are very good as a supplier.  Interested to see how you get on.  Peelply will go around curves, you might just need separate pieces.  The results of be overlapping peel ply patches can be seen in the glass finish but if you do it right any signs are easily rubbed back.

 

good luck.

 

 

Edited December 23, 2022 by MikeQ

[Peter Garsden]

Christmas is the time for goodwill to all men.....and pilot painting. Have decided that he shall be called "Reg" which seems suitably 1940's.

[Ron Gray]

Looks like he’s been on the sauce again.

[Andy Meade]

A fine paint job sir!  Good choice on the glass finish too IMHO.

 

[Peter Garsden]

A few weeks off from modelling due to a skiing holiday the last day of which I collided with a kerbstone piece of ice left by a snow cannon, which was blocking the slope at about 40mph and came to a dead halt. In the process I managed to fracture 7 ribs numbered 3 to 9 down the left hand side of my rib cage. Ever since I have been in agony and unable to do anything. Today was the first time I was able to devote about 2 hours to some repairs and the installation of the aero-tow servo.

 

The plan shows quite a meaty servo attached to the side of the fuselage about 10cms from F1. Due to the size of my pilot "Reg", There was no room where the plan showed, so I decided to use a very small slim wing metal digital servo which is only 8mm thick. The torque is not quite as high as a Hitec 85mg rated at about 3 to 3.5kg/cm. I hope it will be sufficient at 1.9kg/cm.

 

 

You can't quite see that I glued the servo to a piece of 3mm birch ply using a mixture of laminating resin and microballoons then screwed that to F1 using servo screws. I cut down the servo horn to accomodate the correct measure of movement - 10mm and programmed the servo to the spring switch on the transmitter

 

 

The other end pokes out of the nose. I have now dremmelled off the excess so that 3mm protrudes beyond the stainless steel bar across the auto-release mechanism. So to use it, one threads a loop of fishing line under the bar with the mechanism retracted then activate the release to trap the loop with the piece of wire, thus locking it in position ready for take off.

[Peter Garsden]

Despite my best efforts, most modelling tasks hurt because I have to bend over the bench and move my shoulders. Also things start to ache after a while so I cannot do much. I hope this will improve soon. I tried to fly but the constant rotating of my neck and shoulders were too much, so I had to pack that in. Strange because I thought I would manage OK.

 

I have now covered the fuselage in 25g per sq metre fibreglass cloth. Because I have had trouble with joins before, I tried to cover the whole fuselage in one piece, which was a mistake as the resin went off before I could lay on the peel ply. I should have done it in sections. This has meant a lot more sanding down before paint.

 

 

I have also added a layer of "Freddy's Sauce" which consists of equal quantities of light filler, water based resin or floor varnish, and talcum powder. It is magic stuff and easier to apply than undercoat/filler primer. I am still using just the lightweight filler for some of the parts which have escaped the sauce. More filling and rubbing down to be done yet.

[McG 6969]

I'm still very happy a lot of modelers seem to like Freddie B's (Secret) Sauce...

I first used it on my Depron take of Peter's Ballerina and then shared it with the community.

... "some water moved under the bridges" since then, I guess.

 

Get well soon, Peter.

 

Cheers

 

Chris

 

 

 

[Peter Garsden]

2 hours ago, McG 6969 said:

I'm still very happy a lot of modelers seem to like Freddie B's (Secret) Sauce...

I first used it on my Depron take of Peter's Ballerina and then shared it with the community.

... "some water moved under the bridges" since then, I guess.

 

Get well soon, Peter.

 

Cheers

 

Chris

 

 

 

 

Thanks Chris. Yes indeed Freddie's sauce is very popular and works really well. I used it on my Spitfire and it produced such a smooth surface.

[GrumpyGnome]

Yes, hope you can recover and enjoy the fruits of your labours..... 

[Peter Garsden]

So, ribs are a bit better (9 weeks) but not a lot better and am able to do a bit more than previously, so have strung up the fuselage for airbrushing - lots of coats needed

 

The Airbrush I use is an Iwata HP-TH which has advantages and disadvantages but overall for doing this type of big spraying task is ideal. It needs a larger compressor because it is a cross between an airgun and an air brush. It covers however very well, and also comes with a smaller nozzle for finer work, but there are limits because the needle is quite large scale ie 0.5mm

 

 

It also makes life easier to use specially mixed primer for airbrushes - no tricky diluting needed

 

 

This is actually a Sparmax compressor from airbrushes.com. Always a good idea to match your compressor with the requirements of your airbrush. This works really well and is good quality.

[Ace]

@Peter Garsden much coverage/area do you get from one 60g one shot primer please?

[Peter Garsden]

On 11/03/2023 at 18:32, Ace said:

@Peter Garsden much coverage/area do you get from one 60g one shot primer please?

I just looked up the spec and can tell you that the cup is rated at 15cc or 1/2 oz which I know doesn't help, but I fill this about 3/4 full. This lasts for one coat of the fuselage thereabouts. I reckon that to cover what I need, I will go through about 45ml of ready mixed airbrush paint. That will be about 4 coats, so not too bad.

[Peter Garsden]

Well we are nearly done with the airbrushing methinks. I have given the fuselage about 6 coats of white primer before overlaying about 4 coats of Flame Red which is the closest to Solarfilm Red I could find which I am using for the fin, the tailplane, and wings in combination with some clear for the flying surfaces.

 

 

The cockpit area is masked off because that has been painted in white. It needs another coat of red before overlaying clear gloss lacquer.

 

 

Next was the canopy which I completely covered with Tamiya yellow masking tape before drawing on the frame lines from the plan - width 4mm. I used the two flexible rulers you can see, which work really well. I then used a brand new blade in the scalpel to make sure of clean lines. You have to press but not too hard to avoid going through the plastic canopy as well s the tape.

 

The first coat is just plain white to give the inside of the canopy the correct colour and also to give the red the correct base. I changed the nozzle of the airbrush from the fan shape to the single hole to get a narrower coverage.

[Peter Garsden]

 

OK so the fuselage is done apart from the  closed loop rudder system, and the wires for the spoilers/ailerons, so onto the wing which is covered in film. I have got some clear Hobbyking Film left over from the Flamingo, but I am not sure I have enough for both the root open area and the ailerons. So I decided to start on the ailerons, which are covered. Next is the inserted clear film for the outer wing section. To get the shape right I used a 4B pencil rubbing paper template as shown, which worked just fine. I will use it to cut out the red solarfilm to the correct shape also.

 

 

This shows the fuselage with the rudder and AMT fitted

 

 

I have made 4mm wide black lines out of Solartrim which makes the join so much better. This is the rear assembled. I tried the balance and I think it will be spot on with no extra lead needed, so fingers crossed.

[Peter Garsden]

I think we are nearly done with the Petrel. I have covered the wings in a combination of clear film for the outer half of the wing and red Solarflim for the inboard half before the gull join. I would have used clear for all the built up bits but I did not quite have enough, and it is now unavailable at Hobby King. It seems to have been on back order forever.

 

On the Flamingo I used some different plugs I had not used before from 4 Max called Maxlock - https://www.4-max.co.uk/maxloc-connectors.html The only problem was that they are 6 wires wide and sometimes get stuck when I am attaching the wings, so this time I opted for the green Multiplex plugs I usually deploy for mouldies. Whilst they are a bit narrower one has to reinforce the joins to avoid the connections working loose.

 

 

For about £30 you can buy a machine to make the hot glue reinforcement of the wires, but I do my own with a couple of pieces of scrap aluminium to compress the hot glue when applied. The one on the right is awaiting application. This article tells you more - https://www.gliderireland.net/multiplex-green-plugs-mold/

 

 

[Peter Garsden]

I didn't show you all the steps I have taken since the above, as they are fairly self explanatory. 

1. The metal skid along the bottom of the fuselage. I got a piece of 20mm wide 1mm thick aluminium off Ebay, cut it to length, drilled 6 holes where shown on the plan at the front and back, countersunk the holes, then marked the relative positions on the balsa keel, drilled progressively bigger holes up to 6mm for the wooden dowels which I glued into position with the 5 minute PVA adhesive. This is a better hole gap filling glue than the Titebond Aliphatic Resin I also use. I then drilled pilot holes in the dowels, bent the skid to follow the shape of the keel and screwed it into position with 4mm screws.
2. Balancing weight - the C of G is 85mm from the leading edge of the wing according to the plan. It needed quite a few pieces of lead to bring it into position. I feared that I had inset too much lead behind the P38 filler nose, but not so. With Reginald in the cockpit there is little room for even the receiver, so I had shoe horn it into the instrument binacle of the canopy. I now understand why Chris made it detachable with screws - so that one can insert lead inside it, which I screwed into position from underneath.
    

Finally here are some pictures of it assembled. It weighs in at 7.62lbs, which is not far off Chris's estimate of 8lbs. It is a handsome beast. I now await a suitable day to launch off the slope.

 

 

I still have to tidy up the servo wires inside the cockpit, glue in some guide tubes for the aerial wires, make some pieces of 2mm carbon rod to secure the wing joining bands, and make a wire hook for retrieving lost wing bands. Oh and very large radiator insulation bags, and some more "Petrel" vinyl sticker for the ailerons, plus stick on my Operator ID somewhere. Still stuff to do.

Edited May 8, 2023 by Peter Garsden

[Phil Cooke]

beautiful job Pete, that looks the business - lovely scheme!

[Peter Garsden]

Finally, the closing up of the gap underneath the ailerons which is quite large because they are top hinged, Chris W has a very clever system of strips of mylar held in position by double sided tape.

 

 

The double sided tape is attached to the wing and the ailerons move within the mylar umbrella.

 

[Peter Garsden]

So...maiden yesterday up at the back of Roaches, Flash, near Leek, which is a perfect site for a maiden as long as the wind is NE to ENE. The forecast said 15 to 25mph which was perfect, if a bit strong for the Petrel, but Chris's Magazine article told me that it could cope with stronger winds. In fact the stats showed that it was slightly under the weight of Chris's prototype as follows

 

Weight 7.62 lbs/3.46 kg.

Wing Area 7.39 sq ft.

Wing Loading: 16.712 oz sq. ft.

 

Pretty good for such a big glider. I wouldn't launch it in anything higher than 25mph, and am planning to use it for aerotowing if I can find some information about the Sherlow Event. Well I am provisionally going but being a newbie to aerotowing it is a bit auspicious. Will have to rustle together a towline methinks. Oh gawd.

 

So how did the maiden go? Well I arranged to meet some chums to help with the launch of such a big glider (to me anyway!). When we arrived it was a bit chilly and I should have taken my microlight suit. Good medium strength wind, so I attempted to assemble. Even though I thought I had screwed in the hooks for the wing hold together bands in the right place, I hadn't done so. The rear ones were more or less in the right position but not the front ones which I had to remove and replace with Diamond Tape to hold the wings on. Not a problem, but they are now fixed and in the correct place.

 

 

 

The big moment came. I was a bit nervous about the incidence of the wing. Bob gave me a good heave ho, and she was off. I had to feed in some up elevator so added some trim. Too much so I used about half of the trim travel and she was zooming around perfectly. She actually rises in the turn rather than falling out of the sky as some mouldies do. Against the hill she looked lovely.

 

 

I tried some loops which pulled round very well, a stall turn which was perfect, a Chandelle, then I thought I would try a roll. Chris had specified 50% Aileron Differential which was dialled in. I also mixed in some rudder with aileron as per the Flamingo, which worked very well. No sign of adverse yaw (whatever that it?)

So I clicked in full rates and decided to try a roll. Later in the day the wind moved a bit to the North and the lift improved. We were followed by Buzzards and a Red Kite, whom we also followed for thermals. A lot of height then a dive followed by a roll. I just couldn't believe how quickly the model rolls. Amazing. It might be the thin wing tips which cut through the air but I hardly needed any down elevator and the speed of the roll was like an aerobatic glider. 

 

I had 3 long flights which I thoroughly enjoyed. I would like to try it out in very light winds to see if it stays up - according to Chris it does so.

 

Thank you to Dave for taking the pictures.

 

 

My transmitter allows me to put the Butterfly elevator trim on a rotary knob so that you can adjust it in flight. I thus took the glider up high and tried out the crow brakes. I gave it slightly less up elevator which worked well. You can see here it coming into landing with full crow applied

 

 

 

Edited May 13, 2023 by Peter Garsden