--- Summary ---
The project assignment is to suggest a brake chute design for the new electric land speed record vehicle “Green Envy” that will be built in New Zealand 2018-2019.
Green Envy is a sidecar streamliner motorcycle, very similar to its predecessor “KillaJoule”, which is built and raced by the project supervisor Eva Hakansson (http://evahakanssonracing.com/greenenvy/). The goal with the motorcycle is to become the world’s fastest motorcycle (current record is 376 mph/605 kph), and the target speed is 400 mph/644 kph. It will have over 1000 HP and be about 7 metres long. The planned debut is in Australia in March 2019.
--- Background ---
Brake parachutes, or “brake chutes” for short, are used to stop extremely high speed vehicles in short distances. Brake chutes are necessary for fast land speed racing vehicles, and also a regulatory requirements for several vehicle types, including streamliner motorcycles. For speeds over 250 mph, two brake chutes are required (but only one has to be used during normal operation, the second typically serves as a backup).
Brake chutes come in a variety of different versions, all with their advantages and disadvantages. A lecture about brake chutes from NASA Space Systems Engineering can be found here: https://spacese.spacegrant.org/uploads/Homework8/Parachutes%20Lecture.ppt
The Thrust SSC, the world’s only supersonic car to date, uses a ribbon-style chute. It can be seen during low-speed testing here: http://bloodhound1.efar.co.uk/sites/default/files/styles/content_image/public/Thrust_SSC_slows_on_a_runway_test%5B1%5D.jpg?itok=iDUho0G4
The Bloodhound SSC, designed by the same team and aiming for
1000 mph, will use the same style chute. Brief information about that system
here: http://www.bloodhoundssc.com/project/car/braking-systems/parachutes
It was recently tested behind a road car https://www.digitalnewsagency.com/stories/9232-jaguar-f-type-performs-mission-critical-parachute-deployment-test-for-british-world-land-speed-record-challenger-bloodhound-ssc
--- Project ---
The Green Envy could use the brake chutes from its predecessor KillaJoule. It uses ribbon-style chutes manufactured by Stroud in the U.S. The chutes cost NZ$1,500 each and are made to order based on vehicle speed and mass.
KillaJoule has a set of 5 chutes in working condition, but they are 7 years old and starting to show both wear and age. As the chutes wear, their stopping force decreases. The aging also dramatically increase the risk for brake chute failure in the form of ribbon or line breaks, causing a significant safety hazard.
When racing on dry lake beds (salt or dirt), at least 4-5 chutes are needed because the chute has to be washed and dried after each use. It collects salt or dirt when used, and if it were to be re-packed in that condition it may not deploy correctly.
A gallery of brake chute deployment photos of the KillaJoule is found at the bottom of this page: http://evahakanssonracing.com/killajoule/. Compare the first two photos that were taken when the chute was almost new in 2013, with the following series of deployment photos from 2016. The worn chute does not develop as well and provides less braking force. The last picture states that the ribbons are made of Kevlar, but this information turned out to be incorrect. They are likely nylon.
The chute deployment can also been seen in this video at 1:58 min: https://www.youtube.com/watch?v=HiXMcaYP9Xc The reason for deploying both chutes was to slow down as quickly as possible, because the front tire had delaminated at 216 mph and was overheating and smoking. Normally only one chute would be deployed while the second one serves as a backup.
The project assignment is to suggest a brake chute design for the Green Envy. One option is to purchase a new set of Stroud chutes. An absolute minimum of 4 chutes will be required, to a total cost of NZ$6,000. However, the team is not happy with the cost/quality relation of these chutes. Full braking power is only generated for the first 5-10 deployments, which results in a high cost per use.
The team would either want a cheaper chute that can be
replaced often, or a much more wear resistant chute that can be used many times.
A chute design that could be manufactured by team and thus save on the cost of
labour would be highly desired. There may also be another design than the ribbon style that is equal or better, and perhaps cheaper to manufacture.
Suggested deliverables:
·
Compare different chute designs:
ribbon, panel with no holes, panels with holes, etc. from a perspective of
braking, deployment, and wear characteristics.This deliverable will include reviewing publications about parachutes for different purposes, including for re-entry of spacecraft. It may also include interviews with other racers and with manufacturers of brake chutes.
· Suggest a chute design suitable for 400+ mph/644+ kph that will stop the Green Envy in a pre-determined distance. This will include CFD (computational fluid dynamics) and other mehtods suggested by the FYP team.
· Design a test setup and method to test a chute (full scale or scale model) in the university’s wind tunnel.
·
Manufacture a chute (full scale or scale model)
and test it in the wind tunnel. Determine if the results from the relatively low speed wind tunnel are applicable to the real vehicle travelling at over 600 km/h.
· Suggest a test setup and method to test the chute behind a road car.
· If practical, create one or more prototypes (full scale or scale model) that can be tested behind a road car.
· Perform CFD modelling of the airflow around the vehicle and the brake chute.
Additional work, depending on interest and time:
· Investigate the airflow and the resulting drag around the tail and the chute door/launch opening for an open tail vs. closed tail (the KillaJoule has an open tail, i.e. there are no doors that need to be open to release the chutes). Compare that to safety benefits from an open tail.
Undergraduate
Interest in racing.
Interest in manufacturing and hands-on work.
CACM - Strength of Materials Lab (Newmarket 902 Lvl 3, Lab)
