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May 09, 2018, 02:20 PM
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Oblique wing experimental sloper


Hi, slopers! It's Marc, the oblique wing guy from last Saturday at the Sunset Fun Fly. I'm glad that people had fun scratching their heads over my latest experiment.

I don't have much info ready for you yet, because I only finished taping it together last Friday and still have less than two hours flying time on it. But here's a thread anyway, so there's a place for questions and comments to go.

I've been calling this plane the SlashDot. Wing is EPP, 72" by 9.25" constant chord, MH45 airfoil at 11 percent thickness. Three control surfaces each span 1/3 of the trailing edge (the central flap is optional). The vertical stab is at a fixed angle of 30 degrees, is displaced aft-right so that I could slide it forward a few inches and put a bit of ballast on the front of the circle, and is circular because I thought it looked weirder that way.

These two pics are belly-up to show the servos. The video and the text are oriented with the clean side up and left tip forward.

http://www.solarmirror.com/flying/ob...rom-behind.jpg
http://www.solarmirror.com/flying/ob...-scribbles.jpg

Mehrdad's video from last Saturday:
Marc's diagonal soaring wing (1 min 28 sec)


Sorry I didn't do more maneuvers on the video, but at that point the plane had only been flown for 3 minutes total.


To make something similar, you can just take any straight-across plank wing and turn its fuselage 30 degrees to the left, then add a little extra ballast on the leading edge of the front-left wingtip. I shifted things around to make mine look extra trippy, just for fun.


You fly it just like any elevon plank, except that the pitch and roll dimensions are off kilter and often mixed together. Right rolls feel very different than left rolls, and helical loops are far more natural than straight loops. It's a real brain stretcher to fly.

So far, the most useful thing I've made it do, aside from stretch my brain: under the right conditions (wind straight onto slope, airspeed 2x windspeed) I can cruise back and forth with the wing perpendicular to the slope, doing a "down turn" at each end, and not roll the aircraft at all. This could conceivably be very useful for slope racing.


Cheers,
Marc Ringuette
Pacifica, CA
I fly at Mussel Rock most afternoons
Last edited by marcringuette; May 10, 2018 at 04:07 PM.
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May 09, 2018, 02:24 PM
Piscine Promulgator
surfimp's Avatar
It's the craziest looking thing I've seen in quite a while. Tip of the hat to you, good sir!

Steve
May 09, 2018, 04:21 PM
Objects in mirror are losing
1000MPH's Avatar
Agreed!
May 09, 2018, 04:21 PM
Don't fly Flat !
Duke58's Avatar
Do up the dot to look like a transmitter , do the wing to look like a sword:0
May 09, 2018, 04:26 PM
Registered User
planekrazy's Avatar
Congrats again Marc and great job.

Maybe another application could be DS circles
May 09, 2018, 04:58 PM
Registered User
Thread OP
I'll post a better flight video when I've had a chance to figure out what maneuvers the SlashDot is good at.


For background, "Similar Threads" just led me to this article from 2001 on a nice oblique sloper, Dave Freund's Fast Banana.
http://www.glide.net.au/on-the-wing3...ue%20_wing.pdf

... and also an RCG thread from 2008, where user "Geode" (inactive since 2013) builds a surfboard shaped oblique sloper, and mostly builds a second EPP version.
https://www.rcgroups.com/forums/show...6&postcount=70
May 09, 2018, 05:11 PM
Brett
bjaffee's Avatar
Seems like maybe a Star Wars B-Wing might actually be viable on the slope!
May 10, 2018, 12:22 AM
DWA
DWA
1Corinthians 13:1-8
DWA's Avatar
Cool project.
May 10, 2018, 02:44 AM
bayagliders.com
Here is the actual maiden!

Marc Ringuette Slash/dot glider maiden (2 min 13 sec)
May 10, 2018, 02:45 AM
BMFA 190658
SilentPilot's Avatar
I'm going to have a go at making one of these, they look so strange
Great work!!!

Marc,
I've only just starting looking in to doing this and already the brain stretching has started! The pics that you linked to... is the thing upside down?


Tony
May 10, 2018, 06:00 AM
Slow builder
_AL_'s Avatar
That is awesome.

Al
May 10, 2018, 09:57 AM
Piscine Promulgator
surfimp's Avatar
Marc, is the name inspired by the website of the same name?
May 10, 2018, 11:40 AM
Registered User
Thread OP
Miguel, thanks for posting the maiden video (from Mussel Rock last Friday). The wind was too light to try much, but I had time enough to balance the plane before I took it to Sunset.

Tony, you're right, the two pics (sitting on the chair) are inverted from the orientation of the video and the rest of the text. I edited in a mention of that just now, thanks.

Surfimp, yeah, I thought it looked like a slash and a dot, so I played off the name of the well-known nerd website slashdot.org.


A note on the fairly extreme dimensions of the SlashDot --
- Partly it's just to look more interesting.
- The long wingspan and ballast toward both wingtips leads to very sedate rolls of the long axis, on a time scale of 4 seconds or so.
- The short wing chord and lack of a horizontal tail lead to very quick pitch changes of the short axis, taking a fraction of a second.
- The combination of those two extremes tends to separate out the two dimensions a bit, helping me figure out what's going on.
- The difference in time scales has led me to not try to do mixing of pitch and roll in my transmitter at all. It's all in the pilot's head.
- The oddly huge pizza of a vertical stabilizer is to brute-force the correct yaw angle, since I expected to be clumsily getting the plane out of shape a lot. I don't know if that was a good idea, and it's easy to change later.
Last edited by marcringuette; May 10, 2018 at 11:50 AM.
May 10, 2018, 11:53 AM
DHG
DHG
Kinetic Sculptor
Ohhhh, the names ...

Kite-ana
Sabre Soar
Pare-A-Sail
Slingblade
Reaper
Slant Bar
Angle Iron
Bad Slanta
In-slant-ity
Dangle
Backslash
Sidewinder
Galloping Gauche
Loose Hypotenuse
Pythagoras's Revenge
Mitre Fighter
Z-Square
Zigarette (Zagarette when inverted)
Zingbat

There have to be more, but that's all I've got right now. Cool project, thanks for sharing!

Cheers,
Duane
May 10, 2018, 03:28 PM
Registered User
Thread OP
The wind was good this morning, so I did a quick video of the maneuvers I've figured out for it so far.

SlashDot aerobatics 1 (2 min 24 sec)


Shown: a series of "down turns" from upright to inverted position and vice versa, good for 120 degree changes of direction on the slope; a slow roll; a quick helical loop (I practice a lot of these); then I switch to right-wingtip-first orientation and try some right-handed helical loops and some more down-turns. They merge into figure 8's if you do them in quick sequence. At the end, I demonstrate how to run the battery dry and land in the parking lot. No worries, I taped it back together already.

Cheers
Marc


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