Extreme Performance

Jim HendrixOxford, Mississippi

How to Receive This Lecture

• Not as conjecture• Not as wild eyed speculation• Not as extrapolated theory ______________________________________________________________________

• Think of it as a history lesson!• “No brag, just fact.” – Will Sonnet

A Word About Objectivity

“If you haven’t spoken a number, you haven’t said anything at all.” – anonymous

(Does anyone know the source?)

25% Was EasyOctober - December 2006Cherry Valley - Caddo Mills

Caddo Mills 12/2006 - Day 1

Johnson Baird

Johnson Baird

Caddo Mills 12/2006 - Day 2

Johnson Baird

Caddo Mills 12/2006 Clean-Wing Flights

Symmetries About 50 kts

Worst Case Johnson Errors

Deturbulator DifferencesJohnson 12/2006 Hendrix

12/2007

First Flight with New DeturbulatorsOil-Flow tests revealed problem.

The Smoking GunJohnson Flight #3 Repeated

One year later – New Deturbulator – Heavier Pilot

How is this kind ofperformance possible?

• The objective was to coerce slightly detached flow over the entire suction side of the wing!

• Primarily, two modifications accomplish this:– Passive tape around the leading edge– Deturbulator tape at the transition reattach point

• Unexpected benefit...detached flow on the pressure side too.

Imagine a Virtual WingFlow detaches from surface at step-down near LE.Flow accelerates due to loss of skin friction.Faster flow resists curving with wing camber.Flow hits deturbulator at grazing angle.Modified turbulent flow remains detached to TE.

Anatomy of a Transition Bubble

Greg Cole

Imagine this flattened down and starting at the leading edge.Also, imagine the trailing flow slightly detached and less turbulent.What would happen to skin friction? ... Trailing turbulence?How important is skin friction in attached laminar flow?Is attached laminar flow the best we can do?

Oil-Flow Image of Transition Bubble on Std. Cirrus Wing

Oil-Flow Image of DeturbulatedFlow - Forward Top Surface

Oil-Flow Image of DeturbulatedFlow - Entire Top Surface

Flow Lifting Away from Surface Behind Deturbulator

Close-Up of Deturbulated FlowBehind Deturbulator

Bonus Benefit - Pressure SideSlightly Detached Flow

Normal Pressure Side Oil-Flow -Early Deturbulator Doing Its Thing

All Over the Pressure Side• Where is the bubble?

• Where is the zig-zag turbulator?

• Where is the flow lifting off the surface?

• Where is the flow returning to the surface?

Something Curious at 50 KnotsJohnson 12/2006 Hendrix 12/2007

Sliding Average at 50 KnotsFour Second Intervals

Sliding Average L/DFour-Second Intervals

Two Flights

Are We There Yet?Second 50 kt Speed Run – 12/1/07

Now, what about this one?Jeff Baird, Flight 4, Caddo Mills, 12/13/2006

New Team Member

Jari Hyvärinen, of Sweden, has joined our team. He is modeling deturbulator operation using his own Linflow software that quickly simulates both large and MEMS scale aeroelastic processes.

www.linflow.us

Conclusions1. Extreme performance has been demonstrated!2. Sufficient evidence exists to convince anyone willing to

seriously consider the evidence. Flight logs are available on the web at www.sinhatech.com.

3. Sumon Sinha disserves recognition as the first to envision the possibility and for making it happen.

4. Much research and development work is needed to fully understand detached, deturbulated flow and to make it a practical reality.

A Standing Offer

My glider is available for independent testing by anyone recognized internationally for expertise in evaluating sailplane performance.

Conditions:

• Must cover expenses.

• Must publish only IGC-log corroborated flight data.

• Must fly sufficient flights in conditions suitable for deturbulator performance.