Model Airplanes

Last month, the United States and 22 other countries agreed to the first-ever global carbon emissions standards for commercial aircraft. The standards, set by the United Nations’ International Civil Aviation Organization (ICAO), are estimated to reduce carbon emissions by more than 650 million tons between 2020 and 2040 — roughly equal to the emissions produced by 140 million cars in a single year.

The standards will apply to all new aircraft designs launched after 2020 and will be phased in for existing aircraft models launched after 2023.

John Hansman, professor of aeronautics and astronautics at MIT, led the MIT technical analysis that contributed to setting the standard. MIT News spoke with Hansman about MIT’s role in the international negotiations and whether a less polluting fleet will look much different from today’s aircraft designs.

Q: What technological and regulatory changes will have to be made in order to meet these aircraft emissions standards?

A: If (the standard) is adapted, basically new airplanes in the future will have to be at the state of the art of fuel efficiency. What that means is, the engines and the aerodynamics of the airplanes will have to be efficient, and the targets for efficiency will vary depending on the size or weight of the airplane: more aggressive for larger airplanes that fly longer distances — those would be Boeings, Airbus, et cetera — not as tight for small corporate jet airplanes.

Because fuel, particularly in the past few years, has been expensive, aircraft manufacturers have already been trying

Article source: http://news.mit.edu/2016/qa-john-hansman-first-global-standards-aircraft-emissions-0309

What happens when you tinker with the design specs of a live flyer? Four European scientists with specialties in biology and aerodynamics got together and ran some clever experiments with fruit flies to find out. The biologists found ways to change the shape of the flies’ wings, and the flight engineers measured what happened in performance tests. Their findings, published in Nature Communications, yield some lessons about the capabilities of mutation and natural selection to make modifications on the fly, so to speak.

Aircraft designers have the luxury of changing just one thing at a time and measuring the impact on flight performance. Living things, however, are bundles of requirements that must be optimized together as they develop from the embryo. The authors recognize this difference:

Wing shape is governed by the expression of a number of genes, the modulation of which leads to phenotypic variation. The results of changing the balance of expression bears little relation to the independent parameters engineers vary when designing aircraft wings, yet these are the gene expression-driven shape warps upon which natural selection acts. [Emphasis added.]

How far could natural selection vary a gene for wing shape without introducing unacceptable costs on other parts of the system? To find out, the scientists used RNA interference (RNAi) to alter expression patterns in a gene called narrow for only the wing tissues, without affecting other body parts. They bred four lineages with altered wing shapes that were progressively narrower than the wild type. Then they put them through

Article source: http://www.evolutionnews.org/2016/03/could_you_desig102669.html

Elliotte Friedman
March 8, 2016, 3:19 PM

Elliotte Friedman
  March 8, 2016, 3:19 PM

Months after returning to the NHL from an executive stint with the Buffalo Sabres, Pat LaFontaine quietly reached out to several of North America’s top amateur and junior leagues with a question: “What can we do

Article source: http://www.sportsnet.ca/hockey/nhl/30-thoughts-making-the-nhls-development-model-better/