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Author Topic: Doug Stout's Arrow Canard build (split off from the Stunt kite design tool)  (Read 273976 times)
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Doug S
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« Reply #540 on: January 27, 2017, 11:29 AM »

The following link provides access to the updated specification plan for the Bird of Prey 18.  The change is the type of material used for the joiner, which is now Teflon PTFE with a 1/32 in. ID and a 1/16 in. OD.  On the plans, I included the McMaster-Carr part number.  I also added a stop below the joiner, which is noted on the plans.

https://drive.google.com/file/d/0Bwj9y_lTaMmFWkp0dFpzUEJMVTQ/view?usp=sharing

I removed the older version of the Bird of Prey 18 plan from my Google Drive.  I switched to this tubing after construction of the initial four versions of the Bird of Prey 18 (two for me, one for Phil, and one for Tom), because it was a tight fit to insert the wing spars into the old joiner made from the wire insulation.  Also, the new material is stiffer than the wire insulation, so it hold the dihedral angle better over time.  The four initial versions of the Bird of Prey 18 were upgraded and there was no change in performance.  The tubing is the same type of material that I use on the Bird of Prey 36 and 48.  Very happy it is made in this very small diameter.

Yours in kiting,

Doug
« Last Edit: January 28, 2017, 08:31 AM by Doug S » Logged

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« Reply #541 on: February 01, 2017, 07:07 AM »

Making some more progress on Tom's Bird of Prey 76 Patriotic Eagle.  The following picture shows the panels are sewn together.  Next step is to hem the edges.

Yours in kiting,

Doug

Bird of Prey 76 Patriotic Eagle - Panels Sewn Together
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« Reply #542 on: February 27, 2017, 08:27 AM »

And now there are four.  Finished the Bird of Prey 76 Patriotic Eagle for Tom White.  The following provides a picture of the finished kite hanging in my home and a picture of a happy Tom White holding his new glider kite.

Bird of Prey 76 Patriotic Eagle - Finished


Bird of Prey 76 Patriotic Eagle - Tom White with his new Kite


I have a simple pattern version of the Bird of Prey 76 in process for myself and Scott Skinner.  Also working on a prototype for a new swept forward wing glider kite.

Yours in kiting,

Doug


« Last Edit: February 27, 2017, 08:36 AM by Doug S » Logged

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« Reply #543 on: March 03, 2017, 10:27 AM »

I have been intrigued by canards and swept forward wings since the 1970s.  In the 1970s, a few of us in my model airplane club built canard control line model airplanes as an experiment.  Mine had a swept forward anhedral main wing that looked cool and flew well for its size.  During 2010, I began experimenting with single line glider kites, due to the low wind conditions in northwestern New Jersey.  Based on my experience with my canard model airplane and the NASA X-29 that was evaluated from 1984 to 1992, I started exploring canards and swept forward wings on single line glider kites in 2012.

My first swept forward wing glider kite was a canard, with a swept forward main wing.  It was designed in the spring of 2012 and named the Arrow, due to the color panel layout I selected that gave the appearance of a north arrow on a survey map.  The Arrow required a custom joiner to allow the wing spars to angle forward.  After the Arrow, I designed a second canard in the spring of 2013 to maximize the area of the front and rear wings to reduce the wing loading, which I called the Rapere.  The Rapere had a conventionally shaped main wing with a straight wing spar.  What I found with canard glider kites is the angle between the canard wing and the rear main wing requires adjustment, if one changes the balance point and/or the camber in the main rear wing.  Also, the canards were very sensitive to changes in wind speed and flight speed.  My single line canard glider kites flew well in light wind conditions.

My first single wing swept forward wing glider kite was the Bird of Prey, which was developed in the fall of 2013.  I was intrigued by the layout of the NASA X-29 and the fiction based XT-908 Drone used in the 2013 Robocop 2 movie, which were the motivation for development of the Bird of Prey.  The Bird of Prey wing layout was based on the rear main wing of my Arrow canard glider kite.  Due to the name I selected and the shape of this glider kite, some may think my Bird of Prey was based on the Star Trek Klingon Bird-of-Prey, but is wasn’t.  In the 1990s, I used predator birds as my naming convention for my various competition dual line stunt kites:  Falcon, Talon, Raptor and Bird of Prey.  I decided to continue with this naming convention for several of my single line glider kites.  Since 2010, I have designed and built several conventional swept back wing glider kites named the Osprey, Eagle, Falcon, Hawk and Swift.  Since the Bird of Prey looks like a bird in flight with its wings bent forward for landing, the name was a perfect match.  Regarding my naming convention, the number after the Bird of Prey name is the wing span of the glider in inches, when assembled.  This allows for easy identification of the glider kite size.

The concern with swept forward wings on full size aircraft is aeroelastic divergence, where the aerodynamic lift of the wing produces a twisting force that rotates the wing leading edge upward, which can quickly lead to structural failure.  On the NASA X-29, anisotropic elastic coupling between bending and twisting of the carbon fiber composite material was used to construct the rear main wing to address this aeroelastic effect.  Since my glider kites use a sheet of fabric for the wing, there is no restriction for placement of the wing spars, so I moved the wing spars to the leading edge.  The Bird of Prey also has wing tips with a measurable amount of chord.  For each wing tip, a curved batten is used to tension the wing tip and trailing edge of the wing, which allows the trailing edge of the wing to twist upward under aerodynamic loads.  These two construction features of the Bird of Prey resolve the aeroelastic effect.  The performance of the Bird of Prey glider kites were far better than expected, with very long flat glides, great maneuverability and responsiveness to line commands, when compared to conventional swept back wing and canard glider kites.  The Bird of Prey 36 and 36M became my go to single line glider kite for Indoor Single Line Ballet Competitions.

With the help of Mike Dallmer of the South Jersey Kite Flyers (SJKF) and Daniel Prentice with the American Kitefliers Association (AKA), I was able to obtain approval to fly indoors at my town’s school on a weekly basis.  This new indoor practice venue allows me to fine tune my indoor glider kites and practice potential indoor routines.  With the weekly practice sessions and the invitation to fly at National Air and Space Museum in Washington, DC on March 25, 2017, I was inspired to explore a new glider kite layout.  In late February 2017, I started sketching a new swept forward wing layout, which would be more extreme than the Bird of Prey.  I use AutoCAD to develop a conceptual design for my glider kites.  I then import the shape of the kite into Airplane CG Calculator (CGCalc_1.05_03.xlms, January 23, 2011), developed by Dr. Daniel T. Prosser.  This program provides me with the aerodynamic attributes of the design and helps me determine the initial location for the balance point.  I use AutoCAD to complete the design and make full size templates for construction.

For the new swept forward wing glider kite, I started with the outline of the NASA X-29 rear main wing, which has an extreme forward sweep.  The shape of the NASA X-29 rear main wing would allow me to see how a glider kite performs with this extreme amount of forward wing sweep.  The forward sweep of the X-29 rear main wing is 30 degrees for the leading edge and 45 degrees for the trailing edge.  I drafted the outline of the X-29 rear main wing and then became very creative with what it would look like as a flying wing.  For this experimental prototype, I named it the “X-Wing” in recognition of the NASA X-29.  The X-Wing has 37 percent more wing area than the Bird of Prey with the same wing span.  For the prototype, a wing span of 36 inches was selected, which would allow me to compare this prototype to my contest proven Bird of Prey 36 and 36M.  The X-Wing was constructed like the Bird of Prey 36M, with three different panels of Cuben fabric.  Like my Bird of Prey, the "M" indicates multiple panels.  The wing loading for the X-Wing 36M is the same as the Bird of Prey 36M, so weight would not be a factor in the evaluation between these two kites.

I will provide updates regarding development of this new swept forward wing kite.

Yours in kiting,

Doug


« Last Edit: March 15, 2017, 10:39 AM by Doug S » Logged

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« Reply #544 on: March 03, 2017, 01:20 PM »

no overlaying of Viper and BoP to see the differences yet? interesting Doug!!!!
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« Reply #545 on: March 03, 2017, 02:51 PM »

The test flights indicate the X-Wing 36M is a pleasure to fly.  It is very stable, which I attribute to the long center and the forward wing sweep.  It appears the forward wing sweep provides stability like traditional kites with swept back wings.  The amount of forward wing sweep and the wider wing tips would not allow the wing spars to tension the trailing edge of the wing as desired, where the trailing edge would move upward by 18 degrees as compared to 13 degrees for the Bird of Prey.  The turn for the X-Wing 36M was flat and graceful, which I attribute to the extreme forward sweep of the wing and the vertical movement of the trailing edge.  When comparing the Bird of Prey 36M to the X-Wing 36M, the Bird of Prey 36M is more responsive and reacts instantly to flying line input, but will telegraph poor line commands.  The Bird of Prey 36M also can be flown more aggressively.

Based on the positive flight characteristic X-Wing 36M, my next step was design a prototype that would blend the positive flight characteristics of the Bird of Prey 36M and the X-Wing 36M.  Beginning with the X-Wing layout, the forward wing sweep and the wing tip chord were reduced so the trailing edge could to be tension more like the Bird of Prey.  The center length was reduced to allow the glider kite to be more responsive.  This prototype also was constructed like the Bird of Prey 36M, with three different panels of Cuben fabric.  Based on the shape and panel layout, I altered my naming convention away from predator birds and selected the name "Viper", because the wing shape and associated panels look like a "V".  Also, Viper was the call sign for the top teaching pilot in the 1986 movie Top Gun.  The Viper has 10 percent more wing area than the Bird of Prey with the same wing span.  The wing loading for the Viper 36M is the same as the Bird of Prey 36M, so weight would not be a factor in the evaluation between these two kites.

The following provides the comparison between the Bird of Prey (Blue Outline), the X-Wing (Red Outline) and the new Viper (Black Outline).  You can clearly see the differences.

I will provide updates regarding development of this new swept forward wing kite.

Yours in kiting,

Doug

« Last Edit: March 15, 2017, 10:39 AM by Doug S » Logged

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« Reply #546 on: March 03, 2017, 06:15 PM »

Whoa......... That is neat... Cannot wait to see one in real life!!!
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« Reply #547 on: March 04, 2017, 01:47 PM »

Cool. The change  in aspect ratio should make it a very different kite.

Looking forward to hearing what it's like.

Mike
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« Reply #548 on: March 05, 2017, 07:18 AM »

The initial test flights indicate the Viper 36M is a dream to fly.  It combines the excellent performance characteristics of the Bird of Prey with the more forgiving characteristics of the X-Wing.  The Viper 36M climbs, glides and turns like the Bird of Prey 36M.  The initial test flights indicate the glide slope for the Viper 36M is flatter and longer than the Bird of Prey 36M, which is an unexpected and pleasant surprise for this new design.  I will continue to evaluate the performance of the Viper 36M, as compared to my Bird of Prey 36M.  The Viper 36M may become my new go to single line glider kite for Indoor Single Line Ballet Competitions.

In the future, I may build other versions of the Viper, such as a smaller version like my Bird of Prey 18, and larger more complex and colorful versions using my fighter aircraft layout.  I used prior versions of this fighter aircraft layout on my Bird of Prey 48, 62 and 96.  The color layout will be a further enhancement, using some of the attributes found on the Air Force F-16 Thunderbirds Demonstration Team.

Yours in kiting,

Douglas K. Stout

« Last Edit: March 15, 2017, 10:26 AM by Doug S » Logged

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« Reply #549 on: March 17, 2017, 07:11 AM »

Had the opportunity to fly the Viper last night at my new indoor practice venue.  The initial balance point for the Viper 36M was a little nose heavy, which was fine for the initial test flights outdoors in light wind.  I used 1/4 inch lengths of the nose weight tubing and found the sweet spot for the glide.  Once that was done, I used the Bird of Prey 36M and Viper 36M to run through my various indoor routines, switching to the Viper 36M for the balance of the evening.  After more than an hour of indoor flight time on the Viper 36M, several positive performance characteristics became very apparent.  The Viper is more forgiving then the Bird of Prey when one makes a mistake with line commands.  This is very good for my old hands.  It recovers from a stall very gracefully, loosing very little altitude.  The climb has a wide speed range, where the low end can be flown very slowly and controlled.  The glide is flatter and longer then the Bird of Prey 36M, which was an unexpected and very pleasant surprise.  Also, the glide speed is slightly slower then the Bird of Prey 36M.  Since the Viper 36M wing loading is the same as the Bird of Prey 36M, I attribute these positive performance characteristics to the longer center and the additional forward sweep of the wing.  Currently I am building a second Viper 36M.

After last night, the Viper 36M may become my new single line glider kite for indoor ballet competitions, which was the desired outcome in developing a new design.  At this time, the two Viper 36Ms will augment my fleet of Bird of Prey glider kites, to be used by myself for indoor demonstrations and competitions.  During these activities, I will have other skilled indoor kite flyers evaluate the Viper 36M to confirm my observations.  After I complete this evaluation process, I will determine what to do with this new design regarding availability to others.

Yours in kiting,

Doug
« Last Edit: March 17, 2017, 07:13 AM by Doug S » Logged

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« Reply #550 on: March 27, 2017, 09:36 AM »

Based on the flight performance of the first Viper 36M, I built a second one with a white nose.  The following picture shows this Viper 36M next to a Bird of Prey 36M, so you can see the difference in the shape of the sail and panel layout.

Yours in kiting,

Doug 

Viper 36M (Left), Bird of Prey 36M (Right), Both Under Construction

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« Reply #551 on: March 27, 2017, 09:56 AM »

I had the opportunity to perform with members of the Wings of Washington (WOW) kite club throughout the day on March 25, 2017, at the Smithsonian National Air and Space Museum in Washington, DC.  Thank you to the members of WOW for allowing me to attend and perform.  For those of you who use Facebook, the following link provides pictures taken by Andrew Albosta, who is a member of WOW and a professional photographer.

Andrew’s Facebook page:  https://www.facebook.com/albosta.
Andrew also posted a number of the pictures at:  https://www.flickr.com/photos/bosta/albums/72157678579000043

Flying at the NASM is quite different then flying at our typical indoor venues for competition, where usually the only limitations are the size of the indoor venue.  At the NASM, the HVAC system is on and creating unique air currents.  Also, there are hanging exhibits one needs to fly around.  In the west end of the first floor where we were performing the indoor demonstrations, there were numerous drones of various sizes on display.  The lowest hanging drone was the X-45A, where the center of this drone was only 15 ft. 8 in. from the floor (I measured the distance with my laser ruler).  It also had a hatch door open and hanging down.  Due to the unique air currents in the demonstration area, I test flew my Bird of Prey 36M and my new Viper 36M when we arrived, and selected the Viper.  The Viper allowed me to power through the air currents and fly vertically between the drones along a narrow corridor.  This was a priceless experience for me, considering the pedigree for my swept forward wing glider kites is the X-29, and I was flying under and around an X-Series cousin, the X-45A.  I look forward to the possibility of flying at the NASM in the future.

The following provides a picture me flying the Viper 36M during one of my demonstration performances.  The picture was taken by Andrew Albosta.  Thank you Andrew for sharing this picture.

Yours in kiting,

Doug


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« Reply #552 on: March 27, 2017, 10:34 AM »

For those of us who live in the northeastern USA, this coming Saturday night will be Indoor Kite Flying at the Mother Brook Art & Community Center, in Dedham, MA.  The time is 6 to 9 pm.  All are welcome.  Archie Stewart is running the event and the following provides Archie's Facebook post for this event:  https://www.facebook.com/archie.stewart.50?hc_ref=NEWSFEED&fref=nf

I plan on attending to fly at this great indoor venue, located southwest of Boston, MA.  I will have two of my new Viper 36Ms with me, along with my variety of Bird of Prey glider kites.  Hope you can make it.

Yours in kiting,

Doug
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« Reply #553 on: March 27, 2017, 11:31 AM »

Based on the flight performance of the first Viper 36M, I built a second one with a white nose.  The following picture shows this Viper 36M next to a Bird of Prey 36M, so you can see the difference in the shape of the sail and panel layout.

Yours in kiting,

Doug 

Viper 36M (Left), Bird of Prey 36M (Right), Both Under Construction





Hmm. Would that be my Bird of Prey? Grin
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« Reply #554 on: March 27, 2017, 11:51 AM »

Coop,

Yes that is your Bird of Prey 36M on the right, which I finished on Sunday.  It will be test flown this coming Wednesday night at my indoor practice venue, then in the mail to you.

Yours in kiting,

Doug
« Last Edit: March 27, 2017, 11:52 AM by Doug S » Logged

"We never really grow up, we only learn how to act in public."
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