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Old Nov 01, 2006, 08:12 AM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
1,608 Posts
Flying with Birds

GPW,

Thanks again for the thoughts & tips! Over the last 16 years of flying with the Golden Eagles, Perigrine Falcons, Prairie Falcons, Kestrels, & Redtail Hawks that live in South Park, I've found that the Redtails are most agressive when you are flying close to their nesting area. Most of the others have just been curious / interested... but then, it's been the Redtail Hawk's nesting area that I invaded most closely!

I've found that if I start doing a series of consecutive tight loops, they back off, probably thinking, "This crazy son of a is gonna get us BOTH killed flying like that!" ... (works for me so far, anyway!)

My wife had never wanted to 'break my toys' [-I was capable of doing enough of that all by myself in the early days!]- never really wanted to try to learn to fly RC until late last winter, when the BEAGLE squadron began to fly. She found that the BEAGLE was relaxing to fly, so she now occasionally does fly one of them (after ~25 years of watching me build and fly various models.)

But she's always been fond of raptors of all types- (participated in the migration counts, etc.) and when I first met her before we were married, she had a bumper sticker on her VW super beetle that read: "I BRAKE FOR EAGLES".
And it was true- she'd pull over anywhere, haul out the binoculars, and watch them until they flew out of sight....

When I walked in the house from the shop last Sunday with the first prototype SOARBIRD, her eyes lit up, and she said, "Now THAT'S NEAT!" I can see her flying one of these a lot. I'll have her doing the Eagle paint job on another one of her own before too long, after the control / balance setup on the first one is optimized for her budding flying skills.

(After all, she bought me my first RC glider kit (A Craft Air "Drifter II") for Christmas in 1981, just after we were first married... so she acknowledges that my pursuit / fascination / obsession with things that fly is at least partly her fault!)

VIKING
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Old Nov 01, 2006, 05:30 PM
gpw
“There’s no place like Foam”
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Nothing like an understanding wife....tell her you did it for her... earns many points
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Old Nov 03, 2006, 07:59 AM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
1,608 Posts
Option: Ducted Fan inside hawk body for power?

The brushless outrunner CD-ROM motor shown in a previous photo will have power to spare for flying SOARBIRD; I'll be picking up paint this weekend for the project. But I've also been thinking of another body design...

SPDF had powered a 40" span enlarged Air Surfer / Wind Rider type wing with a ducted fan mounted on top of the wing back in 2002... it was flown indoors at roughly half throttle. GWS commented that the Big Horton was very efficient, and required very little power to fly.

That got me to brainstorming on the possibility of building a ducted fan unit INSIDE the Hawk body... a ~3" diameter hawk body is a realistic size, in relation to this 60" span wing. I ordered some parts to test; the GWS ducted fan unit I'll test is ~2.7" in diameter. (I also have a brushless inrunner motor on order to install in the fan unit, for increased thrust & efficiency over the brushed can motor it will replace.) This will be my first project using a ducted fan... suggestions will be appreciated!

This would allow doing a very scale hawk / eagle head on this bird body, for a very realistic silhouette as it glides over.

The EPP fuselage with the Outrunner motor turning the 8x6 folding prop will be the first prototpe to fly; I will post more photos & info as I get time to work further on SOARBIRD.

VIKING
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Old Nov 03, 2006, 01:29 PM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Might be interesting? The EDF's produce little thrust/amp, and plenty of noise!

I haven't tried one on a floater before...
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Old Nov 03, 2006, 08:58 PM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
1,608 Posts
Quote:
Originally Posted by Gene Bond
Might be interesting? The EDF's produce little thrust/amp, and plenty of noise!

I haven't tried one on a floater before...
Gene,

The video of the 40" wing flying in the indoor soccer arena was what caught my attention and got me considering it; that video is in SPDF's thread on the Big Air Surfer, (linked previously.) As I remember it, he commented on flying on only partial throttle most of the time, and it appeared to be moving well. If it doesn't do the job, I'll figure the 61" wingspan is a bit more of a job than it can handle... (could scale down the wing a bit for the Fan version, too...?)

[Noise isn't what I'm looking for, & a small fan screaming at over 20K RPM may not be my favorite version once I've flown it some, but the clean bird silhouette gliding & thermaling overhead may be worth it in a trade... I expect that if overly friendly raptors with either amorous OR sinister intentions get to close and the high RPM fan is kicked full on, they may have second thoughts

Yes, the efficiency will suffer with a small ducted fan prop... hopefully, with the brushless inrunner, there will be adequate thrust. So maybe doing one fuselage / body to try the ducted fan, and the other one with the CD-ROM outrunner on the nose wil offer a decent comparison...

I'm working on the CD-ROM motor version while I'm waiting for the other parts, anyway. I'll get the control surface reflex set & have the wing flying well, before I swap bodies to test the ducted fan body version.

I'll pick up paints tomorrow, & be ready to get this bird in the air before too much longer!

VIKING
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Old Nov 04, 2006, 12:15 AM
High Altitude Flyer
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Fairplay, South Park, CO
Joined Sep 2005
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CD-ROM Motor install in EPP Fuselage; Spar joining with C.F. Tow

I worked on the motor installation in the nose of the EPP body / fuselage this evening. Here are three photos of the process / approach I used, with captions.

I also installed the two piece tubular C.F. spar on the underside of the wing at aproximartely the center of lift of the airfoil, then added carbon fiber tow in multiple layers over the slight overlap at the center of that spar joint.

I installed 23" of 3/32" bamboo dowel (from matchstick windo blind) to either half of the leading edge, and 23" total across the trailing edge; C.F. tow was also CyA-ed in place to reinforce the center joints in both of these areas. The wing is now plenty strong for a under 11 ounce slow flyer / thermal riding bird!

Servos wil go in after the base coat of the paint goes on the wing. More later!

VIKING
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Old Nov 05, 2006, 07:44 PM
High Altitude Flyer
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Fairplay, South Park, CO
Joined Sep 2005
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Fuselage and wing mounting details, plus a new paint!

Soarbird is progressing nicely; I managed to find a good looking brown spray paint at a Lowes store; it is a new Rustoleum "Fabric Paint" in MOCHA BROWN. This spray paint is foam-safe, and results in a flat finish... nice for a bird! After doing a quick test on a scrap of foam, I painted the tail. It covers well & looks good as a base coat. The wing will also get a base coat of this same brown paint.

The wing will be removable from the body on this SOARBIRD; a couple of screws will be used to hold it in place. (This will allow me to later easily swap to the ducted fan powered body, flying the same wing.)

The ESC & wires are inset in the EPP foam for minimum drag.

Photos have captions to further clarify the build progress.

Wing servos are now installed in the wing tips; long extension wires are soldered in between the servo body & the wire's plug, so the leads reach the receiver mounting location up under the wing. The servo wires follow the back side of the C.F. main spar on the wing's underside. (The motor battery will also get mounted up over the body, under the wing.) I'll shoot more photos when the servo linkages & control horns are finished- this will happen soon.

More Later!

VIKING
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Old Nov 06, 2006, 11:54 PM
High Altitude Flyer
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Fairplay, South Park, CO
Joined Sep 2005
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Ready for flight tests

Here are four photos of the flight-ready SOARBIRD; (the new Rustoleum "Fabric Paint" in 'Mocha Brown' worked well, and bonded well to the Bluecor wing. This paint coat added about 1 ounce to the completed aircraft, and will make a superb base coat for the added trim that will be applied later.

SOARBIRD has the final setup completed, ready for the flight tests. I used two Bluebird BM306 servos and a CORONA RS410 receiver. The final flying weight is at 10-3/4 ounces using the 2S 800mAH LiPoly packs. Wing area is in the 4 square foot range, so the wing loading is under 3 ounces per square foot; (I'll get more precise data and specifications later.)

The 8x6 folding prop is mounted with the short prop adaptor core, and the top forward motor access hatch is vented and mounted in place. The radio receiver is mounted to the under side of the wing; (the flight battery will also be mounted in the EPP body just under the wing.)

I'll do test flights when the high winds we are presently experiencing have let up! - I'll post more details and a flight report before long.

VIKING
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Old Nov 07, 2006, 05:50 AM
gpw
“There’s no place like Foam”
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Very nice and bird-like .... Good Luck !!!
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Old Nov 07, 2006, 06:20 AM
Crash Master
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Indianapolis, IN
Joined Sep 2001
16,632 Posts
Looks great!

Assuming everything works as planned, I bet you've got a new favorite

I am anxious to hear how the EDF tests go. I'm guessing the climb will be a challenge w/o the aid of some thermal lift. Cruise should be fine. once aloft.

I was hoping to learn a new trick or two, thinking you were going to mount a CDR motor in the EDF... I've seen some, but I just haven't tried it, yet.
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Old Nov 07, 2006, 08:30 AM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
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Gene,

I figured I'd fly the tractor motor setup with the folding prop first before setting up a ducted fan; build time is at a premium for a while right now.

I just learned this morning that BPHobbies has just begun to stoick the 8x6 folding prop sets with a 3mm motor shaft collet adaptor; (these were not available yet last week when I had ordered other folding props...)

These are great for use on CD-ROM motors such as the GBv kit motors, etc... Yesterday afternoon I had reworked a 2.3mm collet out to 3mm for use on SOARBIRD- a very touchy job to do without a lathe.

http://www.bphobbies.com/view.asp?id...3&pid=A3558014

VIKING
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Old Nov 07, 2006, 11:53 AM
J. Titors Gr Gr Grandpappy
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Charlotte,NC
Joined May 2005
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72" gws 55 brushed http://www.rcgroups.com/forums/showa...hmentid=780179
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Old Nov 07, 2006, 12:16 PM
INDORUS EXPARAMINTO
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Springfield, Missouri, United States
Joined Jul 2002
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TO COOL FOR SCHOOL

Larry
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Old Nov 10, 2006, 06:04 PM
AMA 125691
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Jacksonville Florida
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Now that is Cool! I'd love to see some photos and videos of that soaring with the local wildlife. Subscribe!
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Old Nov 10, 2006, 09:57 PM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
1,608 Posts
Winds have been up quite strong since SOARBIRD was completed. What is evident at this time (after four rather brief flying sessions in windy conditions) is that

1 - This first wing, as built, is far more ideal for flying indoors, or in quiet or light wind conditions. It is NOT a wing design for windy conditions (which are far more prevalent in the South Park region of the Central Colorado Rockies where I live & fly. This area is more of a slope flyer's dream area...)

2 - the 8x6 folding propeller generated only very modest thrust on the 2S LiPoly battery pack; it's a characteristic of the prop blade design, as a GWS 8x6 slow flyer prop running on a similar motor, same wind, & same battery does generate a lot more thrust. When a 3S 640 mAH battery was used, the RPM went up from 7600 RPM to 10,600 RPM- a major increase in performance. The current draw was still at only 4.7 Amps.

3 - In windy conditions, the first prototype SOARBIRD was subject to the gusts, and lacked stability; let's face it- a big wing with less than 3 ounces per square foot wing loading is not going to perform in gusty windy conditions! It did want some added vertical stabilizer area. So I built a second tail, adding vertical stabilizer area both above and below the fixed horizontal stabilizer. This improved it's handling without disrupting the bird-like look too badly. I'm looking forward to a quiet air flying session now; it's made it through about 25 launches & landings so far in very challenging wind conditions, with no signs of the sheer fright I've likely put this poor light bird through in the process...

4 - The further thought I've come to, in evaluating this SOARBIRD prototype to this stage, is that BlueCor (especially in a single surface undercambered wing of this type) may be less than suitable for a wing this large for outdoor, windy weather flying conditions. There's a lot of wing-warping evident when this 61" span is rocked by wind gusts, and while the wing is generally strong enough for a 10-3/4 ounce airframe, it does lack a bit of the rigidity that I'd like to achieve. The scale of this wing is quite possibly a bit too large for execution in Bluecor, if outdoor flying is a primary task. I'm already working on the design concepts for a ~44' span wing that will handle more winds with far more ease.... and still look much like a stylized soaring hawk when seen from below!

The photo below shows the second tail; (it simply is swapped out with the first tail for the flight testing, and did offer more stability.)
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