Mission Log
Flying a helicopter to an altitude of 3 meters is an ambitious task. Besides the substantial increase in required power, there is a concern about stability, especially since attaining the Sikorsky Prize depends upon being able to stay within a 10 meter square. With Atlas we will have a great deal of control including pitch, roll and collective.
Last week we finished the construction of all eight rotor blades! This represents the completion of the single largest task, and obviously one of the most important components of the helicopter. Each rotor weighs only 5 lbs, with the majority of the weight (3.5 lbs) in the carbon fibre spar. The rotors will be the largest ever built for a quad-rotor helicopter, and will make less than 20 rotations during the length of the 1-minute Sikorsky Prize flight!
This past weekend, a lot of the team and I traveled to Northbrook and Kenosha in Illinois and Wisconsin, respectively. There, we raced on two velodromes. The races were rather casual, and everyone was there to have fun. Everyone was able to ride their bikes on the course, and almost everyone got a ride in the streamliners. We brought the whole fleet of bikes: Ace, Vortex, and this year's Bluenose.
Tests of the first drive spool showed premature failure when a connection between one of the Kevlar spokes and the rim came loose. The rim then buckled at that point. This analysis was only possible using video taken of the failure; the actual event occurs too quickly to observe directly. If the failed part was the only evidence available, it might seem that the rim suffered a material failure and buckled out of its plane of rotation. However, careful analysis of our video file shows clearly that the spoke came loose before the rim buckled.
Our featured sponsor this week is once again Full Speed Ahead! FSA (www.fullspeedahead.com) just donated many of the major remaining components we will need for the drivetrain/bicycle frame, including cranksets, stem, seatpost, and headset bearings. Theirs are among the lightest components available, and with weight being such an important factor on the Atlas, we're happy to have the best. Our heartfelt thanks to the team at Full Speed Ahead!
Our featured sponsor this week is Profile Design! Profile Design (www.profile-design.com) makes high-performance bicycle components, as well as apparel and accessories for triathletes. The company was kind enough to donate a pair of handlebars and a wheelset to our team!
Hey everyone, we’ve uploaded a great new video about assembling the helicopter’s rotors! This is one of the most critical and precise steps in the construction of the entire helicopter. We start with jigging the ribs at the correct orientation, then we tack and glue them in place. The last step is attaching Kevlar tow at the leading and trailing edges of the rotor, to help with drag loads as well as the stresses resulting when we heat-tension the skin.
Congratulations to the University of Maryland team who succeeded in hovering for 50 seconds this week.
This week we”re welcoming several new team members to the project:
First, Congratulations to Nick Martel on being accepted to Med school at the University of Ottawa!!! Several days after receiving his acceptance, with his summer now freed up, he moved up to Tottenham to join the project. Nick is a great addition to the team, with a good attitude, a killer work ethic, and a curiosity in a wide assortment of fields.
Check out this great video, a description and explanation of how the Atlas project team installs “biscuits” or bulkheads in our tubular rotor spars. The biscuits are used to prevent thin-walled bucking, in which the spars can crush like a pop can under twisting and bending loads. They”re small balsa and foam sandwiches, installed with an extremely long pusher tool and tacked in place with wood glue. Pretty unique as far as construction methods are concerned!
We've spent time over the last two weeks finalizing the design of the drive spool and building a prototype of the spool itself and the shaft upon which it is mounted. The drive spools are four large pulleys (one at each rotor) wound with high-strength line that is pulled off to spin the rotor. Each spool must be able to withstand the torque transmitted through it as well as the immense crushing force of the line wrapped around it. However, the part must be as light as possible; the target weight for the entire spool is less than 300 g.
Hey everyone!
Check out another awesome video put together by Jake on the rib production process. Made largely from polystyrene foam and balsa wood, the ribs give our rotors their aerodynamic shape!
Check it out, new video detailing the Spar Production!
