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Slingsby Petrel 3.4m - ChrisWilliams - PreBuildQuestions

General discussion on any topic which doesn't have a natural home on any of the other boards.
Mick666
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Joined: 03 May 2019, 22:30
Location: UK

Slingsby Petrel 3.4m - ChrisWilliams - PreBuildQuestions

Post by Mick666 »

Hello

I'm about to start a CWilliams Slingsby Petrel 3.4m. I've been modelling for 40 years but this will be the largest model I've built to date. I've bought the laser cut option with extra wood from a well known supplier. Bit concerned about the density of most of the extra sheet wood, which goes up to 20Ib.

So for a model like this, what would the usual form, wood density wise, for areas like 1/16" planking and LE sheeting etc. I realise its horses for courses on different areas of the build but I'd rather not be dipping into my own stash if the accepted form says 15Ib is fine. lol, I have to manage the old balsa stash carefully these days :D

I would say that the wood in the regular short kit and the laser cutting is all very good. Just the additional wood pack thats got me wondering.

Any help appreciated.

Mike

PS Most of my wood stash has been built up over the years around building free flight competition duration models so I think of 8Ib as getting a bit heavy :)
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Cliff Evans
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Re: Slingsby Petrel 3.4m - ChrisWilliams - PreBuildQuestions

Post by Cliff Evans »

I think Chris says that his was about 8.5Lb in weight. At that weight, it flies very well. The problem with wood stock at present is that there is only medium to hard balsa available, which in all honesty should not prove to be a problem. I personally don't think that a little extra weight will be a problem with the wing section used. I hear all the time modellers say "it needs to be lighter", more often than not, I feel that the extra bit of weight makes a much better model. With the Pat Teakle range, for instance. I was always being asked to produce epoxy fuselages as they were lighter. When I did make one, the model had to be ballasted up to the weight of the polyester fuss to make it fly anywhere as near the original.
Saving weight is not always the best thing to do with these gliders.
https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
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chris williams
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Re: Slingsby Petrel 3.4m - ChrisWilliams - PreBuildQuestions

Post by chris williams »

I have never found much use for soft balsa, probably because it would fail to survive my landings. I recommend hard balsa for the wing sheeting, otherwise you might need more wing ribs to prevent putting your fingers through. The ply planking on the fuselage is a pain to apply, but super-tough and will laugh at rough slope landings...(Having said that, Trevor successfully planked his in balsa and made a saving in weight, but, then he knows how to land properly)
Mick666
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Joined: 03 May 2019, 22:30
Location: UK

Re: Slingsby Petrel 3.4m - ChrisWilliams - PreBuildQuestions

Post by Mick666 »

Hello

Thanks for the feedback, I’ll not overthink it too much then :)

Learning all the time.

Cheers

Mike
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