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Gliders => PSS => Topic started by: EI1638 on March 18, 2018, 13:20:19 PM

Title: Sectioned
Post by: EI1638 on March 18, 2018, 13:20:19 PM
Folks,

Any recommendation on a section for a ~1 m span jet.

Model is a West Wings Hawk. The plan so far is to stretch the span slightly and reduce the size of the intakes, both as recommended on the Facebook PSS group
It did occur to me that it might be worthwhile changing the section also since this will never be an EDF.

I know I can while away a few hours googling and reading to find a collection of contradictory recommendations, but it's always easier to ask...

Option 1 is to use the existing ribs/section
Oprion 2 is to make a builtup wing with a new section
Option 3 is to make a foam core wing for it (been a while since I cut one of those), with a revised section.

I'm leaning towards option 3 as washout is required and that would seem to me to be easier to build into a foam wing.

Having said that I've built plenty of wings with washout, it just wasn't deliberate...

Chris
Title: Re: Sectioned
Post by: billscottni on March 18, 2018, 18:22:13 PM
Try E374 or SD7037
Title: Re: Sectioned
Post by: EI1638 on March 19, 2018, 15:17:51 PM
Thanks Bill.
Title: Re: Sectioned
Post by: Fred on March 20, 2018, 10:08:08 AM
Howdy,

I would use a HQ, maybe a 2 or 2.5 series depending of the thickness (that's pretty much similar of Bill's one, but a tad thicker) at root, evolve to a 1.5.

I never put washout, as that create more issues at high speed. Easier to build! :)

Nice model anyway! :)

Fred
Title: Re: Sectioned
Post by: EI1638 on March 22, 2018, 09:52:10 AM
Thanks Fred.

I've been busy comparing profiles on airfoiltools.com, so I can see what the differences are. They all look quite a bit different to the shoe soles I'm more used to building - one historical aerobatic section was reputedly based on a US Size 9 shoe sole.

I suspect any high speed issues will have more to do with the pilot than airfoil/washout (or lack of) with me at the controls.

This could turn into a serious project yet.

Chris