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Sep 29, 2005, 07:03 PM
PGR
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Low AltiDude
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Yippee!

My Zipper: A Radical Departure From The Rut I Was In


Leave it to my Niece .. The one that's right far more often than a girl her age has a right to be. On a recent visit she noticed that the vast majority of my electric and slope planes were yellow on the top and red on the bottom and quipped: "Uncle Pete, you're stuck in a rut!"

Indeed!

I was in the process of building a new "opportunity" plane to keep in the truck and decided to do something real brave and experiment with a new color scheme for a change. I still had most of an industrial-sized roll of Bright Yellow Ultracote so that color didn't change but after an arduous several minutes in front of the Ultracote rack in the local hobby store I chose ....

Apple Green!

TOP


BOTTOM


Ok, so it's not a radical departure but it is different (at least for me). And among the people I typically fly with, green just isn't a color found on the planes save for the dark olive green found on many warbirds.

Here are the specifics:

Kit: 3-Spar Wing Warrior Zipper

Equipment: 4xAAA 720mAh NiMH pack, HS-85MG servos, Sullivan 2-56 Splined Nylon Flexible (Gold-N-Rod) pushrods, Berg4 receiver, 2.1x5.5mm axial charging/switch jack.

Items of note: 1/8" x 3/16" Basswood drag spars with 1/8" Basswood gusset on TE.


The foam on the TE of the wing cores was cut back 1/8" before gluing the drag spars on. Not doing so will move the combined weight of the drag spars and elevons an additional 1/8" behind the CG and that has a significant impact on the CG. I use Goop in a "contact cement" role to glue the drag spars on. Once in place, the drag spars were sanded to match the taper of the TE.

While the drag spars do add some rigidity to the wing, their real purpose is to maintain a straight and true TE. Without the drag spars it's nearly impossible to cover the wing without deforming the TE but with the drag spars in place, it's possible to shrink the covering tight while maintaining a perfectly true TE. The drag spars also make it possible to double-bevel the elevons and use CA hinges if you're a flexibility freak but with servos like the HS-81 & 85s, I've found no real advantage to this over the single-bevel elevon with double-tape hinge method.

From the nose back, the equipment goes: battery pack & servos, receiver, switch jack. The receiver location is offset a little because I forgot that the servo/battery plugs add length to the receiver. The charging/switch jack is mounted to an oversized plate made of 1/8 balsa with an EPP foam overlay. Under the plate is a pretty good sized cavity for the switch jack to hang into. This cavity is also large enough to contain all the extra servo & battery wiring. Before I install any components, I punch a 3/8" hole from the battery to the receiver and switch jack cavities for all the wiring. (a 3/8" brass tube sharpened on one end makes a perfect core drill for this purpose). I offset that 3/8 hole so it exits the battery cavity where the lead exits the battery pack.

I applied a liberal coat of thinned Goop to the front 5-6 inches of the nose, 2" of the LE, and 1" of the wingtips (top & bottom in all places). Then I applied 3M Extreme strapping tape over the Goop on the nose and LE. The drag spars eliminate the need for the crossed strips of strapping tape along the TE. Once covered, the only visible indication that there is any electronics at all in the nose is a 5.5mm hole in the film for the charge/switch plug. I'll make a dummy plug with a "Remove Before Flight" ribbon to act as a switch.

This is actually the first Zipper I've built this way but I've done a couple of Raiders the same way except I used 4xAA 1100mAh NiCd packs instead of the AAA NiMH pack. The optimum flying CG came out nearly perfect without any nose ballast on those Raiders and I believe the same will hold true for this Zipper. Wing Warrior suggests 6-1/2 to 6-3/4" back from the tip of the nose and this Zipper balances at 6-7/8". AUW = 335g / 11.82oz.

I haven't flown it yet 'cause the wind has been dead calm this afternoon but my guess is it's going to fly prettu near perfect just as she sits. I will probably do some decorating but I want to see what kind of CG adjustments are going to be necessary first. Maybe I can fine tune it with a couple of strategically placed stickers or something.

So there's my new "opportunity" sloper. From the top it bears evidence of a rut I used to be in but the bottom just smacks of Kermit the Frog.

Maybe I'll get to fly it some day.

Pete
Last edited by PGR; Sep 30, 2005 at 12:49 AM.
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Sep 29, 2005, 07:14 PM
Scorpian 60'' 2012
BMtech's Avatar
Looks good Pete (what about the Lma) Green will be hard to see in the bushes?


Rick
Sep 29, 2005, 08:10 PM
PGR
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Low AltiDude
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Quote:
Originally Posted by BMtech
Green will be hard to see in the bushes?
Not too many bushes growing in the Pacific Ocean and it's the backdrop at most of the slopes I fly.

And the brush and bushes don't stay green for long in these parts. 'Bout 3 weeks into summer it's all turning brown or black (depending on whether it burns or not).

And what's an lma?

Pete
Sep 29, 2005, 09:29 PM
VTPR & Slope Aerobatics
surfimp's Avatar
Mmm, Lemon-Lime!

Looks cool to me... have fun flying it!

Steve
Sep 29, 2005, 09:36 PM
Scorpian 60'' 2012
BMtech's Avatar
Pete,
Itís like that with the bushes here to. We are in a drought at the moment so every thing is just brown.

Itís a lost model alarm.



Rick.
Sep 30, 2005, 01:04 AM
PGR
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Whew, am I ever glad I decided to test fling my new Zipper on level ground a couple of times to test the trim before I tossed it off a cliff. There was WAY too much elevator reflex at neutral stick and the damned elevator travel was reversed. I'm surprised I didn't catch that for all the building and flying I've done but it snuck right by me.

Actually, I didn't even check. I just copied the Raider model which works fine on the Raider but the Raider servo sequence is right-left (Hitec) and the new Zipper is left-right (Multiplex).

>> Sigh <<

Oh well, no harm done and it's all dialed in and ready to go now.

So what I need is the wind to blow instead of suck.

Pete
Sep 30, 2005, 01:17 AM
PGR
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Quote:
Originally Posted by BMtech
Itís a lost model alarm.
Ah!

Never have used one. Doing so would wreck my sense of adventure.

Pete (who always enjoyed a good Easter egg or treasure hunt)
Sep 30, 2005, 09:34 AM
The Predator
The Predator's Avatar

Sweet Swept Wings


Pete-
Cool build, I am glad to see some quaility builders showing off their build skills on combat wings, aside from the servo digger . Happens to all of us, well, me at least.
I wish all the best builders would do this kind of thing. I have been trying to get more excitement going about these wings but was surprized by the lack of interest in building a sweet swept foamie. I think the HP, Double VVs super speed Manta, and others have helped to show that these kinds of wings should be respected as a relatively cheap easy build with LOTS of POTENCIAL. At least at our hill, the VAST majority of air time is had by these fiesty little buggers and a TON of cheap nasty fun, is there a better kind???
I just finished a modified Bee that I will be posting about in the Bee forum. Maybe it will give you some cool new ideas.
Sep 30, 2005, 09:59 AM
Embrace the suck
nauga's Avatar
Quote:
Originally Posted by The Predator
I have been trying to get more excitement going about these wings but was surprized by the lack of interest in building a sweet swept foamie. I think the HP, Double VVs super speed Manta, and others have helped to show that these kinds of wings should be respected as a relatively cheap easy build with LOTS of POTENCIAL. At least at our hill, the VAST majority of air time is had by these fiesty little buggers and a TON of cheap nasty fun, is there a better kind???
Kitbashing 'em can be fun too

https://www.rcgroups.com/forums/show...7&postcount=55

Nauga,
who skipped the part about 'quality' build
Oct 01, 2005, 08:08 PM
PGR
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Low AltiDude
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It's A Keeper! (Maiden Report)


Well I flew the new Zipper today in some decent lift. Not great lift (for Reef Point, anyway) but decent. And as the title of this posting says, it's a keeper! Not only is it faster than my Raider but it out-turns, out-rolls, out-loops, and out pumps it by a substantial margin. In fact, that lil' bastiid even flies in lighter air than the Raider does.

A 6-7/8" CG is definitely not too far back. It certainly doesn't tuck in a dive test and may even loft a bit but I'm not done trimming it out. By the time I got the linkage mechanically optimized the wind had swung hard West and was hitting the slope at an accute enough angle that the lift sucked so I haven't even started optimizing the TX setup yet.

Something tells me the Raider's going to spend a lot more time at home.

Pete
Oct 01, 2005, 08:20 PM
cranium accessories
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Love the green! (my fav. color)

Good luck on the tuning.
Oct 02, 2005, 10:20 PM
PGR
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Well I got to fly the little yellow and green beastie again today and I continue to be in awe. To recap, I eliminated the need to add any weight to make CG by careful (and mighty lucky) component placement. My flying weight is less than 12oz and I was initially afraid that it was going to be too light to accelerate well when coming down out of a pump and too light to retain much energy on the up-lines.

But this little baby dives like a meteor and carries the energy through maneuvers much better than my Raider. It's also a lot faster and there's no question that it will fly in lighter lift.

Light is right! That isn't what I expected, but I'll keep the little booger anyway.

No, it won't be replacing my Halfpipe or my Moth but the old Raider certainly won't see as much air time.

Pete


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