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Old Gliders Petrel gull wing dihedral question

Let us all watch your new project progress.
Ken Long
Posts: 13
Joined: 13 May 2018, 19:24
Location: Wellingborough

Old Gliders Petrel gull wing dihedral question

Post by Ken Long »

Hi Folks,

I wonder if someone could assist please?

My Petrel build is progressing, but I wonder if I (or Old Glders) have got something wrong....

With the kit came numerous build photos including a hand drawn diag of the gull break dihedral. This clearly shows that the TOP of the outer wing panel is at 0 degrees in line with the wing joiner rods. However, now that I have jigged up the wing then spliced and glued the top spar, I notice that the supplied ply braces are not at the same angle.

So question is, should it be the BOTTOM of the wing outer panel that is at 0 degs?

Many thanks,

Ken
Barry_Cole
Posts: 101
Joined: 26 Jun 2022, 00:51
Location: Hampshire

Re: Old Gliders Petrel gull wing dihedral question

Post by Barry_Cole »

I guess our friendly Petrel builder will answer this later..

8-) 8-) 8-) 8-)

BC
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chris williams
Posts: 1572
Joined: 10 Mar 2015, 10:50
Location: Blandford Dorset

Re: Old Gliders Petrel gull wing dihedral question

Post by chris williams »

Yes, as seems to be the style of the times, the lower surfaces of the outer wing panels are in line, leaving a slight anhedral to the upper surfaces
Ken Long
Posts: 13
Joined: 13 May 2018, 19:24
Location: Wellingborough

Re: Old Gliders Petrel gull wing dihedral question

Post by Ken Long »

Many thanks Chris.

So the info from old gliders is wrong. I tried to post the image on here but it would not let me. Ho hum.

I'll have to get wifies steamer out to separate the joint and start again!

Well at least I spotted it before fitting the ply braces and doing the other wing.

Since posting this I managed to find a plan of the full size one and that looks like it is the bottom surfaces that are at 0 degs too.

Many thanks again.

Regards,

Ken
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Cliff Evans
Posts: 1035
Joined: 29 Dec 2019, 15:13
Location: Bristol
Contact:

Re: Old Gliders Petrel gull wing dihedral question

Post by Cliff Evans »

Ken Long wrote: 26 Nov 2022, 10:45 Many thanks Chris.

So the info from old gliders is wrong. I tried to post the image on here but it would not let me. Ho hum.

I'll have to get wifies steamer out to separate the joint and start again!

Well at least I spotted it before fitting the ply braces and doing the other wing.

Since posting this I managed to find a plan of the full size one and that looks like it is the bottom surfaces that are at 0 degs too.

Many thanks again.

Regards,

Ken
Why did it not allow you to post the pictures? Was a reason given?
https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
Ken Long
Posts: 13
Joined: 13 May 2018, 19:24
Location: Wellingborough

Re: Old Gliders Petrel gull wing dihedral question

Post by Ken Long »

Hi,

When I click on the 'Post Image' icon it just inserts this in the message img/img

I have just noticed the 'attachments tab below so have tried adding the photo that way.

Yay! I can see from doing a preview that works.

Many thanks.

Ken
Attachments
Creating Gull Wing dihedral.jpg
Ken Long
Posts: 13
Joined: 13 May 2018, 19:24
Location: Wellingborough

Re: Old Gliders Petrel gull wing dihedral question

Post by Ken Long »

Well, I managed to separate the splice by carefully using a steamer and water on a cotton bud once the joint started to open.

Now re-glued and braces fitted to give zero degrees on the underside - few that was close..

Many thanks,

Ken
Ken Long
Posts: 13
Joined: 13 May 2018, 19:24
Location: Wellingborough

Best glass cloth weight for a 5m Petrel fuselage.

Post by Ken Long »

Hi All,

I'm having a 'senior moment' here...

I have glassed skinned many a fuselage over the years, but I can't remember what gsm cloth to use. Would 25gsm be OK, or would you recommend a heavier one?

Many thanks,

Ken
Jolly Roger
Posts: 577
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Old Gliders Petrel gull wing dihedral question

Post by Jolly Roger »

Hi Ken,

50 gsm would be my minimum. The threads of 25gsm are just so thin that one careless stroke of glass paper and you’re almost through them, weakening their strength.

My choice of cloths would then depend on which material I was glassing on to, the weight of the model and what I’m landing it on.

I’m guessing your 5m Petrel will be about 18-20lbs? If you’ve ply sheeted it like Chris’ prototype, then I reckon one layer of 50gsm would be fine. If it’s balsa sheeted or you might be flying of rougher slopes, then I’d add additional layers under the nose, possibly including a panel of 80 or 100gsm for those pesky rocks!

Hope this helps.

Rog
Last edited by Jolly Roger on 28 Nov 2022, 11:22, edited 1 time in total.
Barry_Cole
Posts: 101
Joined: 26 Jun 2022, 00:51
Location: Hampshire

Re: Old Gliders Petrel gull wing dihedral question

Post by Barry_Cole »

Why old you want to land on rocks?????

8-) 8-) 8-) 8-)

BC
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