How the 1950s Tilt Rotor Aircraft Led to 3D Technology We Use Today
The tilt rotor aircraft holds great promise for improving air travel in the future. Research efforts have begun in the early 1950s to produce an aircraft that could take-off, land, and hover like a helicopter -- but with the speed of an airplane.
Why this would be awesome:
- The vertical take-off and landing eliminate long runways at airports
- The airspeed of over 340 mph make it a great short commute vehicle
The big challenge, however, is the noise. For instance, the noise from the tilt rotor during landing is LOUD, and is why the aircraft hasn’t been widely accepted.
During 34 years of testing, a lot of techniques were tested to not only decrease the acoustic signature of the XV-15, but to also increase its efficiency:
- The shape of the blades were changed a number of times (by mounting prefabricated sub-wings on to existing blades).
- A new control hardware was introduced to reduce noise.
- A major alteration was the design of a 4 bladed rotor to replace the 3 bladed rotor.
The problem, however, was that in the midst of 34 years of testing, by the time the aircraft made its way to the Smithsonian, it traveled with a truck full of “change orders” and “as built” documentation; as a result, no one was quite sure about the exact dimensions and the shape of the aircraft.
How 3D Technology Saved the Day
Having an artifact in a museum that curators couldn’t easily define was embarrassing. Even more embarrassing was when modern researchers made inquiries about the aircraft specifics, and no one had the answer.
Enter 3D technology.
In 2018, NASA Ames sent a team to scan the whole aircraft and create a 3D model, not only to create a historical record and resolve any future questions about the shape of the aircraft, but also to help build a 3D model that can be used in building models for Computer Fluid Dynamic (CFD) simulation.
To eliminate the possibility of misaligning the scan data and to combine the accuracy of photogrammetry with the resolution of 3D technology, NASA team adopted and implemented the following measurement plan:
- Geodetic V-STARS photogrammetry system which utilizes a special calibrated camera taking multiple pictures from various locations of circular retro-reflective targets applied to the surface of the model. This creates an accurate, but a very coarse mesh.
- MetraScan 70 metrology system, which utilizes a handheld 3D laser scanner to measure large complex surface geometries.
- Handy 700 portable metrology system to measure small complex surface geometries.
- The 3D model created with photogrammetry was “covered” by stitching scans from MetraScan and Handy, using appropriate reference targets.
This approach of using a combination of photogrammetry and 3D scanning to create “as-build” models is becoming more and more popular.
Today, it is used in the following ways:
- Architectural documentation
- Historical preservation
- Demolition projects
- Upgrading and documenting plumbing systems
- Video game environment designs
Currently, one of the most popular applications of this technology is in the field of construction. For new construction, renovation or retrofit projects, the 3D scanning provides architects and general contractors with the information and insight into how to fix issues and make critical decisions before they cost time or money.
Once the project is scanned and the 3D model is generated, the 3D model provides an easy and economical way to generate “as-build” drawings required for permit sign off, and most of the drawings have a correlation of better than a 1/1000 an inch to the actual building.
Another interesting application is for Facility Management. For instance, if the cable routing and plumbing is documented in a 3D space, upgrading your facility becomes a lot more manageable; you would know exactly what needs to be removed, what will stay, and how much free space you will have for your upgrades.
And to think, it all started in 1950.
About the author: (Alex Sheikman)
I work at Ames Research Center, which is a National Aeronautics and Space Administration (NASA) facility located at Moffett Field, California. Currently I am serving as a Project Manager for the development of Tiltrotor Test Rig (TTR), a test bed that will provide the Department of Defense and NASA with a new national test capability to conduct technology development, test and evaluation of new large-scale proprotors. Rotors up to 26-ft diameter will be tested up to 300 knots. More information and pictures of the TTR are available at the Revolutionary Vertical Lift Technology (RVLT) web site at: https://www.nasa.gov/ames/feature/unique-tiltrotor-test-rig-to-begin-operational-runs-at-nasa-ames I have also contributed stories and art to "Robotika: For a Few Rubbles More" (Archaia), "Legends of Mouse Guard" (Archaia), "Dark Crystal: Creation Myths" (BOOM!), and self published "Kristo."
All posts by Alex Sheikman