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Old Mar 08, 2010, 05:13 PM
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Hawaii
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DP,

Was the tape stuck completely flat, or was part up in the airstream?
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Old Mar 08, 2010, 05:44 PM
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R.M. Gellart's Avatar
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That is one question DP, was it dead flat*, and was it way out at the tip (like it sounds from what you said)?

Marc

*Cause when I see guys slap tape somewhere for reuse, it usually is not dead flat in any sense of the word.
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Old Mar 08, 2010, 06:48 PM
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Orange County, CA
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Quote:
Originally Posted by Daryl Perkins View Post
On launch, it got ugly, and the model pulled SUPER hard to the side where the tape was. It required all my rudder, and a bit of aileron to get the model up tow..
Clearly a case of severe lateral imbalance!! Like flying all the gas out of one wing tank!!!
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Old Mar 08, 2010, 08:13 PM
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United States, VA, Falls Church
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No, it was pretty flat for the most part. It really surprised me that it had that dramatic of an effect. I'm sure it was somehow just exactly in the wrong place... but it certainly made me rethink any and all stickers on my wings....
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Old Mar 08, 2010, 08:30 PM
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It is certainly feasible that surface irregularities can have an effect on the flow over the wing. There are PLENTY of factors involved with "tripping" the flow, DP's experience would be a severe case.

I have used pinstriping tape to tame tip stalls on small UAV's and other large UAV's use zig-zag tape to control the flow. X-foil is pretty good at predicting the bahavior of a "trip" since you can specify a point on the airfoil. It is then up to you to find a way to get it to trip on the real wing.
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Old Mar 08, 2010, 09:03 PM
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Hawaii
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Hard to second guess, but..... I wouldn't be surprised if part of the tape wasn't firmly stuck, and with the rapid change of airspeed on launch, a part of it came loose - flapping in the breeze & acting like a spoiler. In the past, when you used to pull wing tape & "temporarily" stick it to a wingtip, would you typically firmly press the tape in it's totality to the wing, as when sealing a wing, or did you just park it on the tip like an unwanted booger?

To check & be certain, you need to comply with & apply Koch's postulates, & repeat the scenario to see if you get the same results. Try first to thoroughly & firmly stick the tape in the same position & try several launches, then try loosely attached pieces of tape in various positions simulating the original & try several launches. I'll bet that the loosely attached tape is the culprit in spoiler action, and not firmly secured tape. YMMV.
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Old Mar 09, 2010, 12:01 AM
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"To check & be certain, you need to comply with & apply Koch's postulates, & repeat the scenario to see if you get the same results."

......I'll get right on that tomorrow.......

BK
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Old Mar 09, 2010, 02:49 AM
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I was just kidding about the sticker you know.........
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Old Mar 09, 2010, 05:41 AM
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Quote:
Originally Posted by satinet View Post
I was just kidding about the sticker you know.........
LOL!!!

Marc
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Old Mar 09, 2010, 07:16 AM
Chuck it and see!
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All this is sooo funny!
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Old Mar 09, 2010, 07:25 AM
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lol sorry.
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Old Mar 09, 2010, 08:08 AM
Chuck it and see!
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I've forgotten what the thread is about?!
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Old Mar 09, 2010, 09:03 AM
F3B and F3K
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United States, TX, Dallas
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One should maybe add that the V-Ultra++ was quite sensitve on the launch.

My V-Ultra++ could pull hard to one side (or in the worst case do a propeller) if it was not perfectly chucked.
I used a critical set up (towhook), nevertheless all other F3B planes I have flown were far more forgiving in the launch phase.

Daryl, have you used the V-Ultra or the V-Ultra++(slightly more span, wing on a pylon mount) to win the WC in Turkey?

Reto
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Old Mar 09, 2010, 09:44 AM
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Old Mar 09, 2010, 09:59 AM
Daryl Perkins's Avatar
United States, VA, Falls Church
Joined Mar 2007
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I'm sorry, I didn't mean to hijack the thread. Like I said, it certainly was not scientific, or quantifiable at this point. It was a long time ago. I recall the tape being stuck quite well. It took me awhile to even notice it was on the model. But like Reto mentioned, V-Pigs were quite squirrelly on launch, so it doesn't surprise me that a minor disturbance on one wing tip would affect it so. I don't recall it altering the model's flight characteristic, just launch.

Reto - I flew the V-Ultra in Romania in 95, and the V-Ultra Plus in Turkey in 97. Identical planforms (span 3M), the Plus just had a smaller fuse, short pylon, and longer tailboom.

Back to your regularly scheduled Tragi conversation. Marc - Nice meathook. And nice job on the wiring harness. I still want to see one of these things up close and personal. Looks like I'll be headed up to Seattle later this year... I hope to see and fly one then...

D
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