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Old Mar 21, 2012, 12:32 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
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Build advice

Hi All,

Am about to start building a coupld of 6m ASg-29s, I have a Fuselage mold already, and will be bagging my wings.

Questions I have are has anyone experimented with some more modern sections? I know going to a thin section won't exactly help low speed performance, but i am really after a great all around section. i.e. something that will allow me to float around and core a thermal nice and tight, but give me good penetration/efficiency and fun factor on some high speed strip beat-ups. Any advice on sections? I will have a mostly fully movable TE so can camber up the section no worries.

The other question I have is about joiners. What works for user/builder friendlyness? Alu tube?

regards,

Alex
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Old Mar 21, 2012, 12:43 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
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Oh and are there any good build threads around for inspiration?
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Old Mar 21, 2012, 03:44 AM
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Carolynne's Avatar
Sydney Australia
Joined Apr 2007
198 Posts
Hi Alex,

Its interesting that you are doing the ASG 29. Try looking up the thread on the H Model 6m ASG 29 which seems to do all that you are asking. It has a 'modern section" goes fast and slow and is a real hoot to fly too. ( I know because i have one!)


Carolyn
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Old Mar 21, 2012, 04:31 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
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Yes have seen the H model ASG. I will search the section.

Still stumped on the light and simple joiner method
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Old Mar 21, 2012, 04:42 AM
PB of 733kph
ALEX HEWSON's Avatar
Christchurch, New Zealand
Joined Jul 2005
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Found the HQ-DS Sections:

http://translate.google.com/translat...26prmd%3Dimvns

But which one would I be after?
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Old Mar 21, 2012, 09:45 AM
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Larrikin's Avatar
Australia, QLD, Elimbah
Joined Jan 2005
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How long is a piece of string?
If you're transitioning, I'd start with 2/12 at the root, 1.75/10 at the aileron root to 1.5/9 at the tip.
If using a single profile, stick with the 2/12.
Just one man's opinion
D.
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Old Mar 21, 2012, 10:45 AM
yyz
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USA, CA, Paso Robles
Joined Dec 2004
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Alex,

Do a little bit of research and reading before deciding on the HQ-DS sections. The polar for those sections has a pretty sharp knee indicating that they perform well within a narrow speed range and maybe not so well outside of that range:

http://www.rcgroups.com/forums/showp...4&postcount=27

A thickened MH-32 might be a good way to go. That airfoil has been around for a long time and people are still using it on modern scale sailplanes.

My experiences tell me that it really depends on how accurately you can reproduce the section on a finished wing. Using female molds gives you the best chance; anything else diminishes the advantages that some of the more modern sections may offer.

There are a bunch of ways to skin the wing joiner cat. A lot of folks use solid tool steel or large-diameter carbon rods. Another way is to offset the spars in each wing and have them cross through the fuselage and pin into the opposite wing's root rib:

http://www.rcgroups.com/forums/attac...php?p=19248203

Again, spend some time reading other people's (SoarScale2, mikegbogh) build threads for inspiration.

You picked a fantastic plane to model. Best of luck,

Mike


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Originally Posted by ALEX HEWSON View Post
Found the HQ-DS Sections:

http://translate.google.com/translat...26prmd%3Dimvns

But which one would I be after?
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Old Mar 21, 2012, 03:39 PM
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Blenheim, NZ
Joined Dec 2007
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Joiners and foils

Hi Alex, good idea, I guess you are thinking about Neal's fuse? The chord is a bit big for the 29 but perfect for an 18m version of the 28.
For the joiner you could do a carbon one easily. I make quite a few. It is just a case of sizing the tube in Ally. This goes in the wing as the joiner reciever. You then use the same size tube, bend it to your Dihedral angle and draw wetted out carbon uni throught it. Once cured you drop the whole lot in caustic soda in your process shop at work and desolve off the Ally. Bingo you have a perfect fit carbon joiner. Too easy.
On the foil side, I have been having the same thoughts. I has some data here you can have, also a Plane geometry sheet for the 28 - 18 to look at CG and handling and stuff.
Drop me a PM with your mail and phone number if you want to talk about this stuff.

Allan

Great to see you and your Dad at the air tow, inspiring.
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Old Mar 22, 2012, 10:07 AM
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Roodepoort, South Africa
Joined Aug 2007
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Hi There,
I would agree with Mike YYZ above I built 2 x 6mtr sailplanes with the Mh32 and found the speed range great , but a tad difficult to slow down on the slope,
My current favourite are, a bit thicker the HQ 12 /13 foils , not as speedy but good all rounders.

Joiners I use faily smallish diameter alutube with carbon tows pulled through ,but being straight the only di-hedral is gained by slanting the outer tubes in the wing.
Another method that has worked for me is a flat blade type mold made up of light ply and taped/waxed , and then a solid carbon joiner layed up in the temporary mold , you can set the dihedral, after sanding smooth you make a wing box to match with thin ply and then wrap with kevlar or carbon tow before bonding in between your spars and bagging, and many others , personal choice really.
Good luck with the build ASG29 is awesome keep us posted with your progress.
cheers
Mike
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