I think the air cushion idea doesn't work for an ostrich either because it is a flightless bird that uses it's legs to run and it's wings to balance, the running speed of the ostrich is too slow in relation to the wings height above the ground to generate lift. The ostrich just has very strong leg muscles so it can run very fast. Puttig an ostrich on a treadmill in a wind tunnel would be interesting way to confirm my opinion, by putting sensors on the soles of the ostriches feet, we could gauge exactly at what speed it left the ground, we would have to add the treadmill speed together with the airspeed of the wind tunnel flow. I did find a definitive study of ostrich mobility and the authorities in the field did not mention a lift effect of the wings but made several references to them. The following is quoted from a study of ostrich mobility.
Newly reported research concerns ostriches. At first glance, these large birds might seem unlikely runners, but they are actually capable of taking on racehorses and certainly outmanoeuvring predators. Compared with humans, the centre of mass is higher, they have long spindly legs and long necks, and their heads are small. Not only can they run much faster than humans, they look remarkably graceful, even when changing direction. They do run turn differently: "When humans execute 30 degreees sidestep and crossover cuts, braking forces are 26% of Fpmax compared to 6-11% for ostriches executing 15-20 degree turns. Moreover, whereas humans generated almost exclusively braking forces during sidesteps and crossovers, 40% of the net forces observed during turns for ostriches were acceleratory." How do they achieve this remarkable performance?
"Most of the differences between ostriches and humans were explained by differences in body morphology. Ostrich morphology is appropriate for effective maneuvers that require minimal acceleratory or braking forces." "These results suggest that, with an appropriately designed morphological system, maneuvers can be executed with minimal changes to running dynamics." "In summary, ostrich morphology is appropriate for maneuvering without requiring large braking or acceleratory forces."
What stands out in these studies is the effectiveness of design thinking. Some will attribute this design to the powers of natural selection acting on genetic variations, with little or no direct evidence to support this hypothesis. However, there is another alternative, which is to be open to the possibility of this design being real, involving intelligent (rather than natural) agency. Ostriches have traditionally been considered the epitome of foolish behaviour, supposedly burying their heads in the sand. However, their running skills are outstanding and demonstrate superb design. One wonders whether heads are being buried in the sand when design inferences are excluded on ideological grounds from science.
Mechanics of cutting maneuvers by ostriches (Struthio camelus)
Devin L. Jindrich, Nicola C. Smith, Karin Jespers, and Alan M. Wilson
Journal of Experimental Biology, 2007 210: 1378-1390.
Abstract: We studied the strategies used by cursorial bipeds (ostriches) to maneuver during running. Eight ostriches were induced to run along a trackway and execute turns. Ground reaction forces and three-dimensional kinematics of the body and leg joints were simultaneously recorded, allowing calculation of joint angles and quasi-static net joint torques. Sidesteps, where the leg on the outside of the turn changes the movement direction, and crossovers using the inside leg, occurred with nearly equal frequency. Ostriches executed maneuvers using a simple control strategy that required minimal changes to leg kinematics or net torque production at individual joints. Although ostriches did use acceleration or braking forces to control body rotation, their morphology allowed for both crossovers and sidesteps to be accomplished with minimal net acceleratory/braking force production. Moreover, body roll and ab/adduction of the leg shifted the foot position away from the turn direction, reducing the acceleratory/braking forces required to prevent under- or over-rotation and aligning the leg with the ground reaction force.
It is very interesting reading isn't it conceptual.
There is an application of air cushion transport. Several aeroplanes have used this principal.
The Lun-class (Russian: "Hen Harrier") (NATO reporting name: "Utka"; Russian: "Duck") Wing-In-Ground effect vehicle was an extremely unusual aircraft designed by Rostislav Evgenievich Alexeev and used by the Soviet & Russian navies from 1987 to sometime in the late '90s. Wing-in-ground-effect aircraft use the extra lift of their large wings when in proximity to the surface (about one to four meters). It is also interesting to note that this aircraft is one of the largest ever built, with a length of 73m, rivaling that of the Hughes H-4 Hercules "Spruce Goose" and many modern jumbo jets.
The sole vessel of her class, MD-160 entered service with the Black Sea Fleet 1987. Eight JSC Motorostroitel NK-37 turbojets were mounted on forward-located canards, each delivering 127.4 kN (28,600 lbf) of thrust. MD-160 had a flying boat-like hull with a large deflecting plate at the bottom of the hull to provide a "step" for takeoff.
The aircraft was equipped for anti-submarine warfare. It was therefore fitted with six missile launchers, mounted in pairs on the dorsal surface of the fuselage, and advanced tracking systems mounted in the nose and tail. A development of the Lun was planned for use as a mobile field hospital, one which could be rapidly deployed to any ocean or coastal location. Work was begun on this model, the Spasatel, but budget cutbacks mean that it has never been completed.
This aircraft article is missing some (or all) of its specifications. If you have a source, you can help Wikipedia by adding them.
Here is a link to pictures of an aeroplane using this principle
http://www.globalsecurity.org/military/ ... 3-pics.htm
Here is a link to a 10minute plus video of this aeroplane, it is called a Sea Monster but they could have called it a Sea Ostrich because it is so similar to your idea.
http://www.searchthetube.com/JE0H-NFupq ... kranoplane
How fast is the ostrich?
First answer by 24.201.108.73. Last edit by 24.201.108.73. Question popularity: 1 [recommend question]
Ostrich isn't a slouch
The Ostrich is the fastest living animal on two feet. It can reach speeds of up to 60km/h
Devin Jindrich of Arizona State University and his colleagues report that it is their shape and behaviour that allow running ostriches to change direction so effortlessly, improving their chances of escape (p. 1378).
`We want to get at what makes them graceful,' explains Jindrich. While movement in one direction has been well modelled mathematically, the same models cannot easily be applied to variations in movement such as stops, starts, or changes in direction. Jindrich has developed his own mathematical model to describe such changes, so that he can understand how the effects of stability and manoeuvrability constrain organism design. Initially tested on cockroaches and humans, Jindrich wanted to test his model on a high-performance two-legged runner. Ostriches are ideal since they evolved as runners long before humans and have a completely different body shape. Alan Wilson, Nicola Smith and Karin Jespers at the Royal Veterinary College were already studying straight-line running in ostriches, and invited Jindrich to collaborate with them.
The team trained ostriches to run along a track and over a plate that measures the force as the foot hits the ground. They recorded the ostriches' body position using motion capture as they ran in a straight line, or around obstructions. An obstruction on the running track immediately after the plate caused the ostriches to change direction while stepping on the plate. They either turned to the left with a crossover step – stepping with the left leg and crossing over the right – or took a side step with the right leg to bypass the obstruction.
To make a successful turn, a runner needs to move in the intended direction without over- or under-rotating. Jindrich calculated that the ostrich's egg-shaped, horizontally orientated body has a higher inertia than the more vertical human body shape. As objects with a higher moment of inertia are more difficult to rotate, Jindrich predicted that ostriches were less likely to over-rotate than humans. Indeed he found that while humans decelerate to prevent over-rotation, on average ostriches generate fewer deceleration forces. In individual cases the birds generated both acceleration and deceleration forces to control their body orientation, but these are reduced because of their body shape with its higher inertia.
To find out if the ostriches were using twisting forces, or torques, in turning, the team used markers placed near the leg joints to measure the torques produced by the leg muscles. They found that as the leg hits the ground, the angle of the leg is very close to the angle of the force. This reduces the torque and produces similar forces to those recorded during straight running. So rather than twisting at the joints, the torque is maintained and ostriches change direction by simply rolling their body into the turn.
It is this combination of body shape and behaviour that allows running ostriches to change direction so gracefully. Exactly how the muscles generate stabilising forces while manoeuvring will be the focus of future work, along with neural control of the muscles.
References
Jindrich, D. L., Smith, N. C., Jespers, K. and Wilson, A. M. (2007). Mechanics of cutting maneuvers by ostriches (Struthio camelus). J. Exp. Biol. 210,1378 -1390.[Abstract/Free Full Text]
Although only an abstract this is also quite interesting.
Jindrich DL, Smith NC, Jespers K, Wilson AM.
Department of Kinesiology, Physical Education Building East 107B, Arizona State University, Tempe, AZ 85287-0404, USA.
devin.jindrich@asu.edu
We studied the strategies used by cursorial bipeds (ostriches) to maneuver during running. Eight ostriches were induced to run along a trackway and execute turns. Ground reaction forces and three-dimensional kinematics of the body and leg joints were simultaneously recorded, allowing calculation of joint angles and quasi-static net joint torques. Sidesteps, where the leg on the outside of the turn changes the movement direction, and crossovers using the inside leg, occurred with nearly equal frequency. Ostriches executed maneuvers using a simple control strategy that required minimal changes to leg kinematics or net torque production at individual joints. Although ostriches did use acceleration or braking forces to control body rotation, their morphology allowed for both crossovers and sidesteps to be accomplished with minimal net acceleratory/braking force production. Moreover, body roll and ab/adduction of the leg shifted the foot position away from the turn direction, reducing the acceleratory/braking forces required to prevent under- or over-rotation and aligning the leg with the ground reaction force.
Jindrich DL, Smith NC, Jespers K, Wilson AM.
Department of Kinesiology, Physical Education Building East 107B, Arizona State University, Tempe, AZ 85287-0404, USA.
devin.jindrich@asu.edu
We studied the strategies used by cursorial bipeds (ostriches) to maneuver during running. Eight ostriches were induced to run along a trackway and execute turns. Ground reaction forces and three-dimensional kinematics of the body and leg joints were simultaneously recorded, allowing calculation of joint angles and quasi-static net joint torques. Sidesteps, where the leg on the outside of the turn changes the movement direction, and crossovers using the inside leg, occurred with nearly equal frequency. Ostriches executed maneuvers using a simple control strategy that required minimal changes to leg kinematics or net torque production at individual joints. Although ostriches did use acceleration or braking forces to control body rotation, their morphology allowed for both crossovers and sidesteps to be accomplished with minimal net acceleratory/braking force production. Moreover, body roll and ab/adduction of the leg shifted the foot position away from the turn direction, reducing the acceleratory/braking forces required to prevent under- or over-rotation and aligning the leg with the ground reaction force.
I hope this material contributes to the ongoing discussion of introducing the aerodynamics of the ostrich into future Formula 1 design.
