The "Cobra" Revisited....VIDEO ADDED

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Lee Liddle
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The "Cobra" Revisited....VIDEO ADDED

Post by Lee Liddle »

Last weekend at our Richardson Fall combat meet, Gary James asked me why I stopped flying the Cobra in favor of the standard Falcon.

As I explained to Gary how much I loved the way the Cobra flew, but dropped it in favor of the lighter, more simple Falcon, the wheels started to turn. Could I take what i`ve learned over the past 4 or 5 seasons to make the Cobra lighter and more survivable?

The Cobra design came before I added the flexible motor mount to the "wing" design, and before I made the switch to fiberglass spars to save weight on the e-powered planes.

After stretching the gray matter some this week and cutting a little coro and 1/4" basswood, I`ve done a rough prototype of an e-Cobra using a beat-up Falcon wing.

The weight looks promising, even with 6s 2200mah (approx 12.5oz) cells and a dedicated rx battery (1.5oz) on the patched wing. By using an esc with switching bec to save the rx batt weight and maybe going to a 5s 2200 on a higher kv motor to save the weight of one 2200mah cell (2.1 oz), I`m pretty sure that the min weight of 41.5oz for e-ssc could be hit with a new airframe.

The prototype is much too ugly to post pics of it, but if testing goes well I`ll build a fresh 5 or 6 and take pics.

Also since this will use the TFw (Texas Flugwerks?) Falcon wing, It would only take a little development work before Ed/Scott could add the E-Cobra to their expanding line of quality combat kits.

Stay tuned!! Knife
gsjames
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Post by gsjames »

Hmmmmm. Ya' got me interested...
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Ed Kettler
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Post by Ed Kettler »

We will be watching the developmetn and testing.

Ed and Scott
Lee Liddle
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Post by Lee Liddle »

Initial tests with the beater prototype confirmed the need for a "real" E-Cobra, so I came home and rebuilt a better TxFw Falcon wing and turned it into a proper Cobra. I`ll fly this tomorrow at about 43oz, but a fresh plane should easily come in at the min E weight of 41.5oz.

Will shoot some video of it tomorrow after it`s dialed in.

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Lee Liddle
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Post by Lee Liddle »

<font size="4">RTF</font id="size4">

Ok it`s ready to fly. I added some extensions to the fins. They do several things. They add fin area, they give the fins more support, and they will give some protection to the aileron push-rods and horns.

I`ve included a shot showing the layout of all of the radio gear and power system. Tune in later today for a video link.

All up weight on this plane on 5s 2200mah batteries is 43oz. That includes a separate rx battery and extra weight in the wing from repairs. 41.5 should be no problem with a bec and a fresh airframe.


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Lee Liddle
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Post by Lee Liddle »

<font size="6">Video Link</font id="size6">


Flies great!! I took video of flight #2. I`m uploading it to you tube now, but it`s pretty slow. I`ll link it as soon as it`s done.


http://www.youtube.com/watch?v=kFhvIpzWk04
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boiler
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Post by boiler »

Looks like a winner Lee.
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Which_way_is_up
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Post by Which_way_is_up »

That is sweet. The video remembered me of many a test flight in that field. Really flies nice. I've got to get some electric stuff ordered this week!
Lee Liddle
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Post by Lee Liddle »

Thanks guys. The video wasn`t aimed very well, but you can get an idea of the extreme maneuverability of the Cobra. Last weekend there were several times that I couldn`t turn inside a target (mostly due to a very beat up airframe) but that won`t ever be an issue with a Cobra that`s set up right. It`s the tightest turning SSC that I`ve ever flown and it doesn`t have to be tail-heavy to turn tight. It still groves very well. the Snap maneuvers are just insane, and have to be seen in person to be fully appreciated. You can recover from them with no loss in altitude. Insane kind of describes them, Lots of fun to fly.

BTW the crazy maneuverability of the Cobra makes a bladder a "must use" for IC power. Of course with E power you never have to worry about fuel flow. LOL
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Post by EK »

Looks good, Lee.
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Post by gsjames »

Impressive grasshopper, very impressive...[:)]

Lee send me some quickie sketches and I'll try to put together an prototype ic version in time for the North Dallas contest. I think that Scott gave me a set of Falcon wing panels to try on the BattleAxe, but I haven't used them yet, this would be a good application.
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Post by Lee Liddle »

Will do Gary.
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Big Dog
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Post by Big Dog »

If I understand your post.. The wing is the same as the falcon, but with a different tail and motor mount?
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Post by combatgoblin »

Lee,
If you don't mind I will take some sketches to.
Don
Lee Liddle
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Post by Lee Liddle »

Ok Gary and Don, here are the basic numbers for the SSC Cobra. This is drawn on 1/4" square graph paper to scale. 1/4" = 1"

The wing is the TFW Falcon wing cut down to 60". I cut my 2" off of the root because I was using used wings, but with fresh cores you could cut the 2" off of the tip, or just leave them at 32" each. I do like the quick roll rate of the 60" wing though. There is a noticeable diff.

The twin vertical fins are cool, but not mandentory. It flies just as
well with one central vertical, but the twin vert give more support to the horizontal and, as I`ve shown above, the also serve to give some protection the aileron push rods.

CG.....2.75" to 3" at the root.

If you need more info, let me know. Good luck, Lee

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