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Old Apr 18, 2014, 01:23 AM
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Artful Owl's Avatar
New Zealand, Canterbury, Christchurch
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Build Log
Frenzy MkII flyingwing

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This thread was meant to be a blog but I have since decided to move it to this forum.
This will be my first build log. I'm keen to try and express my own style
geared to being more media rich and entertaining.

Here is a link to the original Frenzy Its not a build log just some of the guys on the modeling
science thread helping me work out some of the bugs. The construction techniques will be
the same as in the original and it will be dimensionally similar.

Wing specs
Panel span: 783mm
Root chord: 292.65mm(MH-60)
Tip chord: 100mm(NACA0008)
Sweep: 452.07mm
Angle: 30°deg
Wing Area: 30.74dmē
MAC Distance:327.47mm
MAC Length: 212.08mm
CG: 210.28mm
Wing Load: 39.04g/dmē
Construction: Foam core sheeted balsa.

Power System
Dualsky XM2834EA-9 Brushless motor
Dualsky XC2512BA 25 amp brushless ESC
Turnigy nano-tech 2650mah 3S or
ZIPPY Flightmax 2650mAh 3S
Master Airscrew 10x6 S-2 (Scimitar) Series

Radio Control Gear
FrSky D8R-II PLUS 2.4Ghz 8CH Receiver
Hitec HS-82MG Micro Metal Gear Servo
Hobbyking KK2.0 Flight Control Board

Designing of the fuselage in Solidworks 2013

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Description: Just a few simple sketchers make up the profile for the surface loft.Name: Frenzy design in solidworks 2013.jpg
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Description: Know we have the profiles worked out we use them to loft the surface of the fuse.  This is the rear section. I did it like this because the nose is a little more complex to loft.Name: Frenzy design in solidworks 2013.jpg
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Description: The nose fuselage section uses two profiles in addition to some guide curves to gain its shape.Name: Frenzy design in solidworks 2013.jpg
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Description: And there you have it, one Frenzy fuselage.
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Description: Know we have a surface to work with we can do a set-out for the templates profiles. The thickness of my foam is 50mm so the distance between each profile is 50mm. I drawer some reference marks of the profile and print them out know they are ready to be gl
Cutting the fuselage
Frenzy fuselage (2 min 4 sec)
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Old Apr 18, 2014, 07:06 AM
Herk
HerkS's Avatar
Virginia USA
Joined Jun 2007
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An important design parameter is the twist that you build into the wing.
How much twist depends on it's intended use. More twist for a thermal floater and less for a speed demon.
Curtis Suter has an Excel flying wing spreadsheet on his website that can get a design into the right ball park.
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Old Apr 18, 2014, 07:41 AM
serial scratchbuilder
Granted's Avatar
Canada, BC, Mission
Joined Sep 2012
1,328 Posts
I noticed on your last build you have the male bullets attached to your battery. You might want to consider moving those to the esc and use the female bullets on the battery, less chance of shorting.
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Old Apr 18, 2014, 07:44 AM
Ochroma Lagopus Tekton
Fly Wheel's Avatar
Blackstock, South Carolina
Joined Sep 2007
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Cool looking wing! Subscribed.
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Old Apr 18, 2014, 01:32 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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That looks REALLY SEXY!

One thing though. Drop the full span elevons. The inner half is located inwards too far to work well for either the aileron or elevator functions. All you will get from the inner portion is drag with precious little other effect.

Instead use only the outer half and run flexible pushrods through slots cut into the wing core that extend out and curve smoothly over as wide a radius as possible to meet the elevon horns. Or run the servo wires out and mount the servos out at the mid point of the wing.

I assume that the motor is going on the flat spot at the rear of the center pod?
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Old Apr 18, 2014, 10:19 PM
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Artful Owl's Avatar
New Zealand, Canterbury, Christchurch
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Quote:
Originally Posted by HerkS View Post
An important design parameter is the twist that you build into the wing.
How will wing twist help my plane?

Quote:
Originally Posted by Granted View Post
I noticed on your last build you have the male bullets attached to your battery.
A stupid mistake on my part I wont be doing that agen. Good spooting.


Quote:
Originally Posted by BMatthews View Post
One thing though. Drop the full span elevons.
I assume that the motor is going on the flat spot at the rear of the center pod?
Thanks for the heads up thats really cool that I can reduce the drag even more. I'm using a smaller width control surface than was on the frenzy it had to much control authority. I hope that will dull the response. Iv seen some of that flexi push rod stuff at my LHS definitely going to check that out. yep motor is going on the flat spot on the back it will be inside the fuse a little.
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Old Apr 19, 2014, 02:58 AM
Fremont, CA
United States, CA, Fremont
Joined Jan 2009
1,659 Posts
Wing twist, meaning less angle of attack at the tips, prevents tip stalling. It causes the wing to stall closer to the root and that just results in loss of lift and the wing just drops but remains horizontal. A tip stall can cause a death spiral.
I usually twist my wings after they're built by placing them in the hot sun while the tips are twisted using weights.
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Old Apr 19, 2014, 03:25 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,300 Posts
http://www.tailwindgliders.com/files...ber%202011.zip
A link to the file Herks mentioned.
I presume you'll be making the wings detatchable?Two centre sections,one unpowered for sloping would be cool.
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Old Apr 19, 2014, 06:16 AM
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I had originally thought about twisting the wing but after thinking about it I have decided not to.
The MkI had no tendency to tip-stall and spin even when flying in a tail heavy condition.
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Old Apr 21, 2014, 02:31 AM
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Cut the fuse today it went really well and was pretty quick just a couple of hours in it.

I was looking at the wing design on Friday and I can see an issue with it.

The tip cord is very small in length and thickness and it has very little surface area Iv done away with sheeting the wing in balsa and instead I'm covering it with paper and pva. So know I have reduced strength at the tip compered to balsa sheet.

The problem is how am I going to attach the wiglets to the tips of the wings? Iv been thinking about it all day and come up with nothing.
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Old Apr 21, 2014, 02:53 AM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
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These are carbon tubes in the wing,rods in the winglets.If you incorporate say 25 mm of the wing into the winglets(sort of a L shape)you will be able to tape them on,or use a screw fixing.
What sort of spar system have you planned?
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Old Apr 21, 2014, 04:04 AM
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United Kingdom, England, Kent
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You could also probably glue and then laminate them in with the rest of the wing, if they're permanent.

I've had some success attaching stuff with a hot glue anchor, which I tend to favour if it looks like carbon rods will be too rigid, and tear surrounding material in an impact :

- In both sides, drill a hole to a suitable depth (up to a couple of inches, as long as you'll be able to fill it with hot glue without leaving air pockets), or cut a suitably shaped recess.
- Pump plenty of hot glue into both sides until it fills the hole to excess. The glue should have plenty of mass, and retains its heat long enough to be workable for some time, allowing you to place several of these anchors in each surface.
- Press surfaces together, ensuring that the molten glue from each side mingles and forms a strong single piece.

The result is a strong, impact-resistant anchored joint, in many ways equivalent to, but often stronger than, a nylon bolt.

For attaching thin surfaces, drill right through, and scrape off excess glue from the outside after pressing together, to leave a flush surface.
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Old Apr 22, 2014, 02:12 AM
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I cut the wing pylons, it was ez enough. Cutting the wings, not so ez. I cut five out today and only one of them is useable
I blew up my good hotwire foam cutter some time ago and never got round to fixing it. I borrowed my dads and it is really
good for cutting on a small wire but not so good for longer wire also I dont have any nichrome wire so that dosnt help aswell.
I have ordered some so ill have another go when it arrives.
A bad day for cutting wings.
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This is what I have to work with for attaching the wiglets
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All the cutting is done
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I haven't had to use spars in the past for a balsa sheeted wing. But im not to sure about a paper sheeted wing.
Ill use one of the reject wings to do some tests

Balsa sheeted wing loaded with 13.8Kg of weight.
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Old Apr 22, 2014, 04:42 AM
I don't like your altitude
Stupot46's Avatar
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http://www.rcgroups.com/forums/showt...1921613&page=5
I thought this was a neat way to do winglets on a foam wing.Also check out the amount of stiffening used-and this is a glassed wing.
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Old Apr 22, 2014, 05:04 AM
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BOOM THATS IT! Thanks heaps for the link.
That plane is one serious looking piece of hardware.
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