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Old Jan 07, 2009, 08:31 AM
Where'd The Wise Men Go?!?
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United States, NE, Bellevue
Joined Sep 2007
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I was able to curve up my wingtips on my eagle last night. It was a lot easier than I thought it would be! Plus, i'm surprised how well it holds shape! A little heat does wonders!
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Old Jan 07, 2009, 09:07 AM
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Connecticut, USA
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Lee - I have been thinking the same thing ever since I decided to build the KF airfoil. I guess we won't know until I throw it into the air but theoretically there should be some turbulance aft of the top airfoil due to the feathers. Or, it may all just kinda settle out under the plate and stay there? LOL...we will see.... Another thing I am trying to figure is CG. From what I have read a KF airfoil moves the the CG back to 30% to 40% of the chord but again, if the airfoil is inefficient due to the turbulance of the feathers then perhaps the CG will move as well?


Lee - Viking60 - I also thought of putting that second step on the back of the wing like you have Viking but decided to wait until I at least get the first design in the air. It will be interesting to log flight characteristics and then perhaps add the second step and see if it changes things. I was thinking that it might minimize the turbulance factor.

Thanks for the encouragement!
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Old Jan 07, 2009, 01:42 PM
High Altitude Flyer
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Fairplay, South Park, CO
Joined Sep 2005
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Wynterhawk,

On my Dancer with the top step at 50% of chord, the ideal balance for efficient glide was back at 38% of chord.

On that new Komet, before I mounted the motor & folding prop & all of the electronics, I taped the control surfaces in place, ballasted with ~4 ounces of lead taped under the belly, and then added enough lead to get the balance to my 'theoretical' bance point. Next I started doing hand-tosses. I moved lead around until I had a good clean glide, & marked that resulting balance point for future reference. After doing this, the initial launch on the first check-out event was not as 'exciting' as it would have been without establishing that 'clean glide' balance point in advance.

VIKING
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Old Jan 07, 2009, 02:40 PM
Boffin
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Victoria, BC, Canada
Joined Apr 2001
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Quote:
Originally Posted by Wynterhawk
From what I have read a KF airfoil moves the the CG back to 30% to 40% of the chord but again, if the airfoil is inefficient due to the turbulance of the feathers then perhaps the CG will move as well?
The KF step itself causes turbulence so the feathers shouldn't make much (if any) difference. The KF step does cause a lot more drag but can improve slow speed handling.
You can survive a maiden flight with a forward CG but a rearward CG will probably result in instant death. 30% should be good.

Rick.
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Old Jan 07, 2009, 04:12 PM
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Connecticut, USA
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AC5FF - Lets see some pics!!

Viking/Rick - when the time comes I think I'll try the ol test glides and check to be sure that I'm closer to 30% than 40% before the maiden. Thanks for the help on that as the KF airfoil is new to me and I really didn't have a clue where the CG should be, especially on an experimental bird...er no pun intended??

Lee - I am working on the fuse now and intend on running a 11.1V 2200 Lipo with all the stuff in the fuse, i.e. 3 servos, ESC, 2212-06 outrunner and receiver. Do you think that velcro will hold the fuse securely to the wing/tail section? Or do I bite the bullet and get out the epoxy?
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Old Jan 07, 2009, 05:42 PM
Where'd The Wise Men Go?!?
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United States, NE, Bellevue
Joined Sep 2007
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Hawk..
Was just thinkn about that. I'm trying to get some 'color' on this bird and then i'll toss some teasers out there
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Old Jan 08, 2009, 05:08 PM
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Mini Macaw

I thought you guys might like this. The Macaw has a 30" wing, 5 gram servos and a 8.5 gram motor that should produce almost 1 to1 thrust and the AUW is just over 4 oz. We are going to see if flys tonight. the design is a scaled down Eagle with layers of 4 mil glued underneath the beak to give the head and beak a better look. The long tail feathers were glued to the main tail with a tooth pick. we are going to fly it without the long tail for the maiden.

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Old Jan 08, 2009, 07:21 PM
Where'd The Wise Men Go?!?
AC5FF's Avatar
United States, NE, Bellevue
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That is VERY cool!! Love the paint job - would really stir up a few looks seeing that one flying around! NICE!
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Old Jan 08, 2009, 09:27 PM
PunchDrunk ex-Pug try'n fly'n
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United States, MN, Minneapolis
Joined Jan 2009
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Quote:
Originally Posted by Lee
Here is an update of the update in post 247.

I am building the tutorial building instructions in posts 2, 3 and 4 of this thread. I figure it is better than starting a new thread and the posts were just sitting there. Look at the instructions and tell me if something doesn't make sense.

We are planning on offering the plane with the ailerons cut or the box of parts as explained.

I tried to use a larger coarbon tube as a sleeve to hold two smaller carbon tubes together. The larger tube split with almost no pressure on the smaller tubes so that option is out.

I got the flat 1mm x 6mm carbon strip. Initial testing shows it is stiff and strong enough in one direction and easily fits in a simple razorblade slot. TJ came up with an idea of putting heat shrink tubing over the two pieces of flat carbon attaching them back together so it can be cut for shipping and it seems to work. Hopefully today or tomorrow I will get a chance to try it in a wing. Heat shrink is a simple way to deal with a complex problem.

It looks like domestic shipping will take the box we have found. For Canada and overseas shipping we will have to cut the box down but that shouldn't be to much of a problem. We have been able to fit the entire plane in a 6" x 6" x 22" heavy cardboard box which will meet the international shipping discount rates.

We are getting closer to a final cut date.

Lee
Hey Lee,
Love your Falcon, want one bad! Sent you an e-mail Re:
Ever thought of shipping UPS fewer size limitations. If you have a kit for me I would rather you not cut the carbon spar and ship via UPS my acct#.
Hope to here from you, I'm looking hard for a "Bird-looker" kit as I am not ready to try to cut an airfoil much less a bird copy.
jp.
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Old Jan 08, 2009, 09:55 PM
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ST.LOUIS
Joined Aug 2006
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Been lurking for a while.

Just to clarify some stuff on my bird.

Got a good scale (finally).

312 grams AUW with 3s800 zippy. .

My cg measured a little over 2inches from the LE at the fuse. Following out to widest cord (longest feather on the ailerons) comes to about 10 inches of cord. This rings in about 22% or so.

It is unusaully forward, but I think the short fat tail is the cause for this as the longer/smaller the tail the less work it does rotating the wing on it's axis.

I fly my 3d KF stepped planes at 50-55%. This caused me to try my maiden at 30% which ended up dinging my wing on a small branch and knocking my wing mount loose(Posted this way back). If you toss with a rearward cg this thing will try to come back at ya quick!!!! I'd shoot for 20% and see what happens. I might actually move mine forward a tad to the 20% mark. The rolls get flatter and the nose pitches up less with power as I move the cg forward as it should.

Just my opinion:

Fly a light 2s800 and 25% cg for up high "scale" bird like flight. Should glide around real nice. Cut the power and it'll stall flat. Wouldn't try anything fancy with this.

Fly a heavy 3s pack and 20% for aerobatic high speed fun.
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Old Jan 08, 2009, 11:45 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
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Quote:
Originally Posted by jp electric
Hey Lee,
Love your Falcon, want one bad! Sent you an e-mail Re:
Ever thought of shipping UPS fewer size limitations. If you have a kit for me I would rather you not cut the carbon spar and ship via UPS my acct#.
Hope to here from you, I'm looking hard for a "Bird-looker" kit as I am not ready to try to cut an airfoil much less a bird copy.
jp.
We have EPP Peregrine, EPP Snowball and EPP Pinata kits in stock. Look at post #4 in this thread for details.

Check your PMs and contact TJ at crashtesthobby@gmail.com.

Don't worry about the carbon spar. It is many times stronger than the 1lb EPP Peregrine will ever need. It is significantly easier to work with than the carbon tube. I like it so well I'm going to use it in other applications.

Lee


.
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Old Jan 09, 2009, 01:04 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
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I'm anxiously awaiting videos from some or all of the flat foam and KF airfoil birds.

I would like to see Winterhawks in a wind tunnel and see how the smoke goes around the serrated edge.

I think they will fly well if they are light.

Lee
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Old Jan 09, 2009, 03:54 PM
PunchDrunk ex-Pug try'n fly'n
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United States, MN, Minneapolis
Joined Jan 2009
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Power systems

OMG I just logged on to hobbycity for the 1st time. Are these deals for real? They have Motor, ESC combos for less than twenty bucks! I was referred to them off of Lee's blog. I had already picked up a BP 2820-6 for my upcomming "Peregren". Not just overkill but over spent.The setup I got from my LHS is going back! What's a good set up for the falcon? I would like to use a folding prop. At these prices a guy can afford to go ffast. Towerpro OK?
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Old Jan 09, 2009, 04:59 PM
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Connecticut, USA
Joined Oct 2008
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Lee, workin on the fuse now....waiting for a bonus check (comin next week ) for the electrics, and maybe some weather that's not like 15 degrees!!
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Old Jan 09, 2009, 06:33 PM
Where'd The Wise Men Go?!?
AC5FF's Avatar
United States, NE, Bellevue
Joined Sep 2007
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JP
I picked up a couple of those tower pro motor/prop/esc combos last month. They are certainly powerful; but they do have their downsides.
1) the wires were pretty brittle - haven't busted on me yet, but I'd not do a lot of wiggling on them.
2) the ESC is okay - but a little tough to program. You'll have to search here for better instructions (I got the link someplace) Also, the ESC does not auto-detect the #cells you are running. Took me a long time to figure that one out Swapped ESCs, motors, batteries, etc.. before I finally realized what was going on. LoL
3) the shafts are VERY VERY weak. I nosed over a P51 foamie and bent the shaft. A 3pk replacement was only a buck or two - Definatly buy it!

Overall - Definatly a good buy and I will even say worth the $$. I will buy them again; as you said - at these prices a guy can afford to go fassst.

Lee- I think I really messed up my fuse. I tested paints on spare foam and found a good match - but when I was painting the fuse I had a section get eaten away! Sooo; my weight just went up about 50% on the fuse! filled the area in with light spackle.. still in work too if it weren't for that I'd have some good pics posted already..
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