Scale Soaring UK

I might get some questions in the near future.

Hi all,l am now in possession of a laser cut rain forest from cliff,masquerading as a slingsby petrel kit ,my word what a lot of wood,l will post some pics of the kit in the next few days,hoping to start work on it this month,coincidentaly,in next months RCM&E there is going to be a 1/5 scale version courtesy of chris "mr sailplane" Williams,dont know if anyone is doing a kit for it though,anyway,l am very much looking forward to building the big ,un....lovely cutting cliff,the included wing jig is a kit build in itself,l will make every effort to fully document this build,there is a hell of a lot of it,so its going to take a while

Hi all,thanks for posting the pics cliff,l am looking to get the build underway around the end of the month,as cliff says there is a lot of wood in this kit!!
and that is just the laser cut parts,you do have the option to build each wing in two halves,but l will be building the wings as two panels,l have not made a decision as yet regarding the tailplane or canopy type,the canopy can be left till quite late in the build,but l will have to decide on the tailplane type very early,looking forward to the build,cliff,s laser cutting is excellent as always,so with the B4maiden coming up,and the start of the petrel build May is proving to be an eventful month

This looks fab! And you never know, it may just spark me into starting the Laserflight 1/3 scale Petrel kit I've had since 2006. They sold at least 2 dozen of these kits but I'm not sure any of them got finished. There's a lot of work in those wings!

Good luck with the build Jack (and the B4 maiden too).

Rog

thanks rog,not heard of that company before-laser flight-got any pics of their petrel kit??,cheers,jack.

Hi Jack,

Yes as Cliff said, Laserflight designer Tony Elliott checked out CW's 1:3.5 Petrel before he designed this 1/3 version. I have plans for both on the floor and you can see similarities, although Tony's was created in CAD with laser-cutting in mind from the start. Here's a link if you'd like to find out more about Laserflight: https://www.rcgroups.com/forums/showthr ... ED-RELEASE

The prototype for the Laserflight kit was finished but unfortunately the wings were built with wash-in rather than out, and it did not fly well. Also it had 4 piece wings and ended up rather heavy. The wings were rebuilt with a little wash-out and in just 2 panels, saving weight. Don't know how well it then flew.

Really excited to see how yours comes together. Mine will get built some day... I feel morally obliged as we live on the hill where the original first flew in 1938 and it's my favourite vintage design.

All the best,
Rog

hi rog,just had a read of the link you posted about laser flight,all seemed a bit weird to me,anyway,l hope you get to building your kit,l am in the planning stage now,l like to plan a build before l actually start it,helps to avoid nasty surprises later on,l tend to spend a fair bit of time doing that,along with prepping a jig board.....l don't have a bridson jig like C.W ....but then thats all part of the joy of building ..jack.

Yeah I agree there's no rush is there. Mind you, I've been in the "planning" stage for over 10 years! I can see mine being a retirement project.

Also... in one of those quirky coincidences, did you notice just yesterday there's an Aussie guy starting a 1/3 Petrel in another thread on RCGroups? Hopefully he'll post some photos of his build.

Rog

Ok people,the bench(s) are clear and work on the Petrel is about to commence let me just say that there is LOT of work here so l am aiming for a first flight in spring next year,pictures WILL be posted regularly,along with brief comments.....following a slight wing joiner problem the maiden of the B4 got pushed back,so weather permitting that event will happen next month at Middle Wallop,hopefully Mr Greenfield will be on hand to do the honours ....thats it for now,more soon!!

That's exciting news about the Petrel, Jack. I'm subscribed!

Also good luck with the B4 maiden.

Rog

hi all,thanks to cliff for posting the photos,as you can see the petrel build is now underway,l have chosen the AMT version,simply because it looks pretty!....cliffs cutting is excellent as usual,l am working on the fuz/tail/wing at the same time to speed things up a bit,l fitted hold down blocks to the wing jig as can be seen,the jig is set up for the port wing...it needs to be reversed for the starboard wing,l have chosen to use carbon sheet for the amt crank,together with carbon tubes and rod,purely personal preference,saves a couple of grams in the tail,there are no problems with the build,but there IS a lot of alignment to be checked,cliffs cutting does most of it but it cant do it all, ,something that isnt in the photos is the small support blocks l fitted to the top of the jig..l used these to support the lower main spar in conjunction with tie wraps to secure said spar to the jig to get the correct Gull curve... l suppose tape would work just as well.....l plan on doing monthly updates from here on,these will be mainly pictures,but if l come across anything untoward( ) l will of course explain(l pause here for the sceams of outrage to subside )so,all well and enjoying the build,back at the end of the month!!

GUINESS????,Never,real ale only fer this intrepid aviator!!….cheers cliff.

Thanks for posting all these pictures. I am looking for my next build project and this could be the one!
As we have no hills in Holland for slope soaring I am looking into something with moderate sink speed. Any guess about weight of this beauty?
Main spar cutouts look quite substantial, how are these made? Size is probably more DIY than model plane shop...

Tjarko

Thanks for the info Cliff ..

Bit hard to read, but wing sections are HQ 3,5/18 at the root and HQ 3,5/14 at the tip ?
Still quite thick at the tip, might benefit from a turbulator at 50% chord... Aileron gap will probably do the job too

Tjarko

When the design was created om my computer a 10 kg weight was calculated. the end result is subject to local supplied material density and type of finish and paint used. My Short Nimbus of similar size is 12 kg and fly's very well. it is airborne on the tow within 5 meters.
Without the idea of starting a big discussion, large scale models of this type with a relative large wing area need a bit of weight to make them fly properly.
The 18 and 14% section thickness was determined by data from the original available and is to scale.

G,day guys,
Love this glider and might have to build one next year.
I have to agree with the previous comments about the weight. My PWS101 from Jilles plan,which is a similar size and style to the Petrel,weighs in at a bit more than twelve kgs and it flies really nicely and is a bit of a floater. Keep those photos coming of the build.
Cheers everyone.
Compliments of the season to you all.
Happy days
Lawrie.

oops. Sorry Cliff. Didnt mean to post that twice. Must have got over excited and double clicked it.
How do i delete one of those posts
Thanks.

tjarko,get down to your local diy store/builders merchants,have a good sort though their stock of pine and pick out all the close grain stock..avoid the wood with very wide growth rings...choose all clear knot free wood,a visit to ebay should set you up with a good used table saw...fit a blade with a high tooth count (fine/veneer cut),knock up an adjustable jig/fence and away you go,no real need to splash out on top grade spruce ,l now await the screams of outrage at this advice

Hi Jack,

Good idea to cut the spars from a nice piece of pine.
I have a friend with a table saw.
Inch sizes are hard to get in the Netherlands, better to saw ourselves.
I got pdf preview plans from cliff, very illustrative.

My apologies for creating confusion.
Lets enjoy this beautifull build thread.
I removed my previous remarks as i found them inappropriate in this build log.

Tjarko

The profile is 18% at the root and 14% at the tip. This is to scale and will fly scale like as well
This is a vintage scale glider with all the behavior of the full scale version and are not a modern glass ship.
All my scale gliders have the same profile and fly as they should. With marginal lift I can outlast in endurance the modern glass jobs but not match their penetration(distance) performance. For local flying this last issue is not a problem.

First photo's from Jack

Second lot of photos

And the third lot.

Tail feathers ready to cover once the tape is removed.

A happy new year to all!!

The latest set of Photos from Jack have landed!

Brilliant thanks for posting

Latest pics from Jack.

Latest from Jack.

More photos arrived this morning.

Some more pics from Jack.

Just to clarify..these pics are of the port aileron,the small "tags" are my own addition to help with attatching the ply t/e to the ribs and will become part of the capstrips,also,the pics were taken before adding the 1/8x3/8 balsa infill,not part of the original design,but l felt a little extra strength would be useful here....have you seen the size of cliffs hands??

jack wrote: ↑24 Jun 2020, 22:57 Just to clarify..these pics are of the port aileron,the small "tags" are my own addition to help with attatching the ply t/e to the ribs and will become part of the capstrips,also,the pics were taken before adding the 1/8x3/8 balsa infill,not part of the original design,but l felt a little extra strength would be useful here....have you seen the size of cliffs hands??

It's not my hands that are the problem!!!

Latest pics from Jack.

Well,the petrel is nearing completion,the wings will be ready to cover by the end of this weekend,l will be posting another group of pics next week,pre paint,the build has been very enjoyable,cliff is going to be doing the paint job himself,just as well,it wont fit my paint shop ,he delivered my next project last weekend,l really dont think there can be much of the worlds rainforest left...most of it seems to have taken up residence in my workshop ,will post the pre-build pics soon,cheers all.

The documentation I made for the Slingsby Petrel has been re-instated on the Scale Soaring UK website for those in need of colour schemes other than Red.

https://scalesoaring.co.uk/the-slingsby ... trel-docs/

There is also a list of model kit suppliers in sizes from ⅕ to ⅓ on this page

https://scalesoaring.co.uk/slingsby-type-13-plans/

It has gone quiet on this one, any progress. The one built here in Australia is in the process of covering/painting

I just have to pick it up from Jack and paint, But Wales is locked down so cannot get over there at present!

Hmmmm, now we are in lockdown!!

Lawrie has flown his Petrel down under, this makes him the first to complete and fly the Petrel from Jilles. Well done Lawrie and thanks for the email to rub it in! Mine will hopefully fly at Sandhays in May!

That is an impressive glider!

How does it fly?
What is the flying weight?

tjarko wrote: ↑13 Dec 2020, 13:33 That is an impressive glider!

How does it fly?
What is the flying weight?

Lawrie has told me that it flies very well All up weight is 13.2Kg

tjarko wrote: ↑13 Dec 2020, 13:33 How does it fly?

It has Wiiings.....



BC

Petrel coming in to land, stunning scenery.

Very well done lawrie!!!!!!......she looks a real treat,cliff,s is covered ready to paint if l can ever get it to him ......how did she handle on tow??,cheers,jack.

Hello Jack,
Yes it flew very nicely on tow, it just hung in there and behaved itself. Once off the line i managed to find a thermal quite quickly and up it went. I didn't have any telemetry going but i'm guessing about 450mtrs, so not wanting it to get to far away on its first flight i tested out the control throws. Ailerons are initially a bit slow but when they start to work i had to back off. Throws are 30mm up and 13mm down. Rudder is 110mm each way and and mix with the ailerons is 70%. Elevator is 25mm each way but could be less i feel. also have 60% expo. Air brakes are set at 60 dgs and give a nose down attitude on a landing approach. Not too much. Just a pleasing amount to ensure there will be no tip stall before landing. I did not induce a stall at height but i think it would drop a wing very smartly if you let it go that far. I did follow your build thread and the other one with interest and was hoping you guys over there would have been first up. Will you be flying from the slopes or the flat. I only have the flat field to fly from but would really like to chuck it off a slope one day.
Lawrie.
Merry xmas to all you guys over there and everywhere. Cheers.

cheers lawrie,this damn virus has played havoc over here,the petrel has been done for a while now,but the lockdowns keep getting in the way.....so hopefully she will fly in the spring of 2021,meanwhile,l have another of jillies designs waiting in the wings(ahem,sorry),l have his Blanik L-13 to build, l intend to post the build on here,take care,jack

G,day everyone .
Here's a few more photos of the Petrel now with its final coat of paint and some art work as per the 1949 version of the original.
Only got one flight in on Sunday. Not much lift around and we got rained on which dampened our spirits a little. I have decreased the elevator throw to 20mm up and down which is plenty. Haven't tried a stall yet. I did a slow circle turn and thought it was going to drop a wing but it never did so its very forgiving. Airbrakes are definitely needed on the landing approach or it will never land any where near where you want it too. Don't ask!!!
Lawrie.