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morris

No stabilizers(JVX)=less drag???

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I don't have my aerodynamics books at home with me, but I looked up 'winglet' in Wikkipedia. According to them:

'The exact upward angle (called cant) of the winglet, and its inward angle (or toe) is critical for correct performance, and is determined for each aircraft application. The vortex which rotates around from below the wing strikes the angled surface of the winglet, generating a small lift force that angles forwards relative to the direction of flight — thus the energy in the vortex contributes to thrust rather than drag as it normally would'.

Thia would agree with what I am saying, that winglets aren't there to reduce wing tip vorticies. Instead, they use the airflow created by the vorticy to produce a lift force that is vectored forward.


"Holy s*** that was f***in' cold!"

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I didn't mean that stabilizers had to be pushed out to work, just that in the case of non-rigid stabilizers (like the fabric ones we have on our canopies), they WILL be bulged out if they are working. Think about it, the stabilizer has high pressure on one side and low pressure on the other. The high pressure will push the non-rigid stabilizer in the direction of the low pressure, thus bulging it out.

The bulging isn't necessary for the stabilizer to work, it's just a sign that it is working.

If you can get your hands on the video 'Parabatix', there is a scene where Wyatt Drews swoops over a fire. As his VX (which has stabilizers) flies through the smoke from the fire, you can see a massive wing tip vortex, despite the stabilizer.


"Holy s*** that was f***in' cold!"

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It seems to me that the stabilizers would act more like airplanes with droop tips, rather than winglets. I think the droop tips are normally included on Short TakeOff and Landing (STOL) kits. These will reduce the stall speed, and give better slow flight performance, such as at the end of the flare, extending the swoop.

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once in flight, stabilizers serve no purpose and are definitively only drag.

btw the aerodynamics of winglet design is not a trivial task. there have been many attempts at adding winglets to parafoils, some even commercialized. however none work and ALL are drag. the simple proof is to fly the wing with only one winglet and view the direction of the induced turn.

.
Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

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Quote

Quote

once in flight, stabilizers serve no purpose and are definitively only drag.


How about keeping back the air with higher pressure under the wing flow over the top skin on the side and making wingtip vortexes too?



wow did you really just tell the guy from atair canopies about canopy design...

I have one word for that

SUPER

Dave
http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

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