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Old Oct 14, 2015, 02:42 PM
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Mini Balsa Flying Wing Glider for Powered or Unpowered Flight and possibly for DLG.

Mini Balsa Flying Wing Glider for Powered or Un-powered Flight and Possibly for DLG as well...

Here is a design I did. After having a lot of visualizations over the last 4 years, of a simple minimalist shape and design using old fashion building techniques, except for a few small 3d printed parts, I decided to draw it up. Please take a look at the images with the information and feel free to let me know if anything should be changed that might improve flight performance. Wasn't sure about the elevon size, or where they should be cut, to get more detailed. So if any experts out there would like to scrutinize the design parameters and suggest better ones that would be of great value to me. The current CAD model is use a fully symmetrical airfoil at the root and the transitions to the HS 522. I added 3 degrees of washout or twist to the tip foil. That may seem like a lot, but after looking at a lot of flying wings that have excellent speed envelop and handling, from full scale, to models, I've concluded it will give nice gentle flight characteristics. I may change the twist to about 2 degrees, but input from others might be helpful. I originally started this thread in the flying wing section, but since the goal is for it to be more like a sailplane that can thermal as oppose to a heavy fast wing, I decided to start the thread here. Sailplanes require much more attention to wing design, in my opinion, and I find the soaring community extremely knowledgeable on efficient wing design.

CURRENT AIRFOILS
ROOT - HS 522
TIP - HS 522
2.7 DEGREES OF TWIST
AREA = 240.42 sq in.
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Last edited by RobertTHaas; Oct 17, 2015 at 09:03 PM. Reason: update specs and title for better definition.
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Old Oct 14, 2015, 07:54 PM
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NEW Images

Here are some slight changes to the design. Pod or mid section will be 3d printed. the part that transitions from the wing to the balsa rudders or winglets will also be 3d printed.
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Old Oct 14, 2015, 08:55 PM
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How does your lift distribution look with the blended airfoils? I don't really see a point to having the N0009 at the root, I would just use the HS522 for the whole span and add whatever washout you need for a good lift distribution and easy handling.

Otherwise I like the looks of it, should make a great park flyer.


Mark
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Old Oct 14, 2015, 10:15 PM
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Quote:
Originally Posted by mmattock View Post
How does your lift distribution look with the blended airfoils? I don't really see a point to having the N0009 at the root, I would just use the HS522 for the whole span and add whatever washout you need for a good lift distribution and easy handling.

Otherwise I like the looks of it, should make a great park flyer.


Mark
Thank you for the input. If I got everything setup in xlr5 comparing what I have with what you suggest, would you be able to read the data I post in whatever form you want and take a look at it and tell me what you think the better way to go is?

Thanks
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Old Oct 15, 2015, 10:32 AM
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Originally Posted by RobertTHaas View Post
Thank you for the input. If I got everything setup in xlr5 comparing what I have with what you suggest, would you be able to read the data I post in whatever form you want and take a look at it and tell me what you think the better way to go is?

Thanks
Robert,

I am far from a genius with XFLR5 but I can load up your files and take a look if you want a second set of eyes. The native XFLR5 files are ok for me.


Mark
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Old Oct 15, 2015, 02:40 PM
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Originally Posted by mmattock View Post
Robert,

I am far from a genius with XFLR5 but I can load up your files and take a look if you want a second set of eyes. The native XFLR5 files are ok for me.


Mark
That would be extremely helpful!! I'll try to get a file posted as soon as possible. Today. Right now!

Thanks.
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Old Oct 15, 2015, 11:19 PM
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Originally Posted by mmattock View Post
Robert,

I am far from a genius with XFLR5 but I can load up your files and take a look if you want a second set of eyes. The native XFLR5 files are ok for me.


Mark
Here is the most up to date design parameters I put into xflr5. I simply threw in the dimensions and the current selection of airfoils. I blended the naca and the hs522 together. titled "hs 522 + naca 0009"

I know nothing else except how to import airfoils, blend them and punch in the air-frame parameters. So all other data needs to be setup.

Thank you.

Robert
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Old Oct 15, 2015, 11:40 PM
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The xflr5 files posted above are of the design rendering images below. More slight modifications. all parameters are in nice round metric numbers. Fine tuning the structure so it's easy to build accurately. After I build and test this glider and if I'm happy with the way it fly's, I post video and will be happy to put together a kit for anyone who might want to build one.

Thanks.
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Last edited by RobertTHaas; Oct 15, 2015 at 11:56 PM.
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Old Oct 16, 2015, 12:15 AM
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Quote:
Originally Posted by RobertTHaas View Post
Here is the most up to date design parameters I put into xflr5. I simply threw in the dimensions and the current selection of airfoils. I blended the naca and the hs522 together. titled "hs 522 + naca 0009"

I know nothing else except how to import airfoils, blend them and punch in the air-frame parameters. So all other data needs to be setup.

Thank you.

Robert
I will take a look but it will probably be sunday before I can get to it. Will PM if I have any problems or questions.


Mark
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Old Oct 16, 2015, 08:31 AM
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Mass = 119.44 grams

According to my Solidworks calculations the mass of this glider should be around 119.44 grams.

So that should be in the ballpark if xflr5 needs the weight or mass..
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Old Oct 16, 2015, 09:32 AM
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Image of current airfoil selection 20151016

HS 522 and a new airfoil concoction, HS 522 blended 50% with NACA 0009.
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Old Oct 16, 2015, 10:22 AM
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Originally Posted by RobertTHaas View Post
HS 522 and a new airfoil concoction, HS 522 blended 50% with NACA 0009.
What does Xfoil say about the blended airfoil? Does it still have a low pitching moment coefficient? What was your goal with combining the two? The HS522 is already 8.67% thick so you aren't really gaining any thickness and are really just messing with the camber line and thickness distribution.


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Old Oct 16, 2015, 04:10 PM
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Originally Posted by mmattock View Post
What does Xfoil say about the blended airfoil? Does it still have a low pitching moment coefficient? What was your goal with combining the two? The HS522 is already 8.67% thick so you aren't really gaining any thickness and are really just messing with the camber line and thickness distribution.


Mark
Thanks mark. I'm also making it harder to build on a flat surface, with twist. I think I'll take your advice and remodel it with just the HS 522.
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Old Oct 16, 2015, 04:17 PM
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Thanks mark. I'm also making it harder to build on a flat surface, with twist. I think I'll take your advice and remodel it with just the HS 522.
For something like this I would look at how Traian did the wing on the Evolution W (in the HLG forum). He had cradles laser cut that set the washout and lined everything up without serious trauma to the builder.


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Old Oct 16, 2015, 09:30 PM
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All hs 522 airfoils used for root and tip.

Yes, very interesting way of going about it. I'm going to mill the parts for the first one, after that I will laser cut as many parts as I can, but to avoid compromising on the airfoil's shape because of balsa wood construction, I am going to router out some of the 3D parts like the trailing edge and the wing tips. possibly the LE as well. So no compromise to the airfoil. I think I have it figured out for the most part. The goal is to keep the construction fairly easy for one to build the wing with its intended shape accurately. I may include 3d or laser cut peaces to assist with the alignment and other details that come out. So far, I have it based on the placement of the ribs. As long as the ribs are square and pinned to the plans as accurately as possible, everything else will fall into place. I will be mixing up the grains of the wood to be conducive to keeping things warp free. I won't be milling a wing-let in 1 peace out of balsa, it will have to go together like a puzzle with special attention to the grain. This one is in the works. I will add temporary supports to accurately hold the beginning of the elevon in place, those haven't been added yet.
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