|T-Splines 2011 contest transit winner|
Electric Sailplane: Joseph Culbert, Orange Beach, USA
Prize: Keyshot 2, 3D print of model courtesy 3D Systems, T-Splines T-Shirt.
Prototype Electric Self-Launching Sailplane for Aviastroitel Mechta Co-Op.
This 18 meter wingspan epoxy/carbon resing infused airframe is fitted with a nose mounted 'outrunner' electric motor.
"Outrunners spin much slower than their inrunner counterparts with their more traditional layout (though still considerably faster than ferrite motors) while producing far more torque. This makes an outrunner an excellent choice for directly driving electric aircraft propellers since they eliminate the extra weight complexity inefficiency and noise of a gearbox."
The folding carbon fiber propellor is carefully matched and fitted to tuck neatly into shallow recesses in the fuselage in order to have minimal drag during soaring flight operations. Power and thrust from this system is available immediately upon need and is a major improvement over the mast mounted self lauching drives that deploy from a position just aft of the cockpit. The time to open the covering doors pivot the motor and propellor 90 degrees and then to primestart and warm-up a gasoline motor requires carful forethought and is but to seconds with this configuration.
The batteries are of the Lithium-Polymer type for efficiency and safety. A full charge should let the craft climb to an altitude of 1000 meters which is adequate to begin soaring flight under most conditions. A reserve capacity to take a second 1000 meter climb or a return to the airfield is available.
T-Splines was invaluable in creating the precise airfoil sections which vary along the length of the wing and the washout which is a very subtle twist and is essential for stability. The entire fuselage and wings and tail surfaces were modeled as a single T-Splines surface which gave me complete control and flexibilty in forming the transitions at the wing roots and junctions between the tail surfaces. All the control surfaces and the cockpit canopy were trimmed from the parent T-Splines surface and then joined to form closed solids and fit precisely to the mating surfaces. The landing gear fork was also created in T-Splines using the tsPipe tool.
I was able to essentially 'grow' this organic design inspired by the soaring birds such as the albatross which are masters of efficient long range flight. A craft such as this should be capable of a 50+ to 1 glide ratio meaning that for every foot it drops i will cover 50 feet forward.
The render software Octane was a very important part of my design process because of the speed and clairity with which it reveals the most minor surface flaws. I found that the T-Splines surface when converted to a Rhino polysurface showed seams when rendered in Octane but the more I trimmed the converted polysuface the meshes exported to Octane via the excellent Rhino/Octane exporter script by Sam Page resolved the edge seams as evidenced in the attached renders.
My thanks to all of the team at T-Splines for such an excellent tool and especially to Sky for his webinar which re-inspired me to re-visit this sailplane project.
Very clean model. Nice design.
Great model, gorgeous renders! Nice work.