Wing thickness...effects of sweep and other...

[KrisFlyZ 0]

The sentance in bold came up in a discussion with yuri_base.

The effect of sweeping a wing back (for the same thickness) is to reduce drag by reducing the effective radius of the wing

Since airflow is perpendicular to the leading edge, sweeping the arm wing back is like making the intersecting plane(oncoming air) cut the 'cylinder' at a angle(other than perpendicular).

To visualize, fill a cylindrical glass with water and tilt it. What is the shape that the top surface of the water makes? The resulting shape is as thick as the glass but the resulting shape has lesser drag.

The shape effect of drag page on the NASA website.

http://www.grc.nasa.gov/WWW/K-12/airplane/shaped.html
Similar to the sphere and the airfoil(gradual increase in frontal area with a thinner entry point) of same frontal area.

A quote from the link below.

Quote

This means that aircraft with short wings must fly at a small angle of attack in order to be efficient. Conversely, an aircraft with longer wings will be more efficient at a somewhat higher angle of attack. The higher the aspect ratio the greater the angle of attack the aircraft must fly at in order to be efficient.

It is important to remember that small angles of attack correspond to high indicated airspeeds (relatively speaking) Large angles of attack correspond to relatively slower speeds.

Thus, we can summarize by predicting that a glider, with its long wingspan will have a high L/Dmax, and as such will be able to glide a long way. However, it will inherently need to fly at a large angle of attack and therefore, be quite slow.

A low aspect ratio jet fighter will not be able to glide very far. However, it will be at its most efficient when skimming through the air at a relative low angle of attack and high speed.

Angle of attack at which Max INSANE Clog Glide occurs for objects shaped like a wingsuit flyer (low aspect ratio aircraft).

Speaking of aspect ratio. Don't agree with what we discussed Yuri.

Aspect ratio of wingsuits is on the lower side of 2.

Interesting thing is a suit like the Prodigy has more aspect ratio than any suit with more area.

AR = (span * span)/area

Higher the area lesser ther aspect ratio. Higher the span higher the aspect ratio. Prodigy has the best of both worlds(for a higher aspect ratio ...less area and high span). Any suit with more area than the Prodigy outglides it. But wait, it has a worse aspect ratio.

The max span is limited by the human form.

Without increasing the span artificially, increasing the aspect ratio of a wingsuit is only possible with a reduction of area. Making a suit of relatively higher aspect ratio and large area is not possible without artificially* increasing span.

Kris.

* Time to go Hang gliding. Long term effects of flying such a suit on the shoulders is simply not worth it.

[yuri_base 1]

In my opinion, if you're truly interested in advancing high-preformance wingsuiting, it's time to stop buying wingsuits and start building them. Start experimenting! It's a lot of fun and inspiration, as you become a scientist, an aeronautics engineer, a rigger, and a test pilot all in one person, you.
Most of the sewing can be done with a $100 consumer sewing machine. For thick parts, take it to your rigger or rent some time on their machine.

By openly sharing our results and thoughts, by joining our efforts and talents, we can gather much more knowledge and advance wingsuiting much further in a year than what happened in 10 years since Patrick's first designs.

Did you try modifying leading edge with inserts? Balancing with weights and observing the effects? Transforming WS BASE data into real (planeout corrected) L/D?

All these things - sweep angle, wing profile and planform, size, thickness, balance, inlets, etc. - need a lot of experimentation to come to right conclusions. The more brains and hands work on this, the better the outcome.

Join the revolution!!!

Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

[KrisFlyZ 0]

You mean GBP 100? We pay double here . Investing in a sewing machine definately is worthwhile.

An interesting observation:

Max span occurs with the arms out to the side at an angle lesser than 90. Shoulder points have to come closer to allow lifting arms to 90 degrees.

Kris.

[mfnren 2]

whats up dood? Music blows, but the flying is bad to the bone... http://www.youtube.com/watch?v=vAiJsUXgknQ&NR=1[url]

[tr027 0]

Yes, experimentation is good, provides good learning experiences. Since my time is limited, I'm subscribing to capitalist economic theory which says that you get the most value from a product when the most efficient producer is producing that product. Since I'm not more efficient at wingsuit building than Robi is, I outsource my suit requirements to him. Economics

"The evil of the world is made possible by nothing but the sanction you give it. " -John Galt from Atlas Shrugged, 1957

[KrisFlyZ 0]

Awesome video.

Clicky.

Kris.

[mccordia 74]

Wow...do you think they'll land one of those things some day..>?

eeerrr..

JC
FlyLikeBrick
I'm an Athlete?

[Costyn 1]

Wow... that is nuts... damn I had no idea those things could go that fast. The speeds look comparable to a wingsuit when flying down the side of a mountain. Or was the footage sped up?

Interesting how he needs a small drogue to slow down enough to land the thing.

Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

[mccordia 74]

Accidental Hanglider base?

http://www.youtube.com/watch?v=vV-Z1HbP4Ng

JC
FlyLikeBrick
I'm an Athlete?

[SkymonkeyONE 4]

Quote

In my opinion, if you're truly interested in advancing high-preformance wingsuiting, it's time to stop buying wingsuits and start building them.

I disagree. If you are truly interested in high performance wingsuiting you better get off your lazy ass and actually jump the things. That's not necessarilly directed at you, Yuri. Sitting down at your aerodynamic textbooks and pondering the "what if's" may sound good in theory, but when you get into this hypothetical "perfect" suit and suck worse than a novice in a Classic II don't bitch. Repetition breeds confidence, first-hand knowledge, ability, and ,ultimately, maximum performance.

[VectorBoy 0]

actually jump the things. Repetition breeds confidence, first-hand knowledge, ability, and ,ultimately, maximum performance.

[riggerrob 643]

Thus, we can summarize by predicting that a glider, with its long wingspan will have a high L/Dmax, and as such will be able to glide a long way. However, it will inherently need to fly at a large angle of attack and therefore, be quite slow.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

"Quite slow" is the key point.
Drag increases with the square of the velocity.
Flying slowly minimizes drag.
... improving your lift to drag ratio, aka: glide ratio.

[kallend 2,027]

Quote

Thus, we can summarize by predicting that a glider, with its long wingspan will have a high L/Dmax, and as such will be able to glide a long way. However, it will inherently need to fly at a large angle of attack and therefore, be quite slow.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

"Quite slow" is the key point.
Drag increases with the square of the velocity.
Flying slowly minimizes drag.
... improving your lift to drag ratio, aka: glide ratio.

Lift increases as the square of velocity too.

You should fly at AoA that provides the best Cl/Cd for best glide ratio (in still air), and that depends on the polar of the complete airframe.

JK (licensed glider pilot).

...

The only sure way to survive a canopy collision is not to have one.