Cross Flow Air Turbine (CFAT) Auxiliary Power Unit by AirMach Innovations
Please find below the
The judges consider this proposal to be novel and have not come across similar concepts. Although the pictures provide some insight, they are contradicting to the proposal title (Cross-flow suggests that the turbine would extract energy from wind that is crossing the aircraft perpendicular to its trajectory).
The issue of the APU is certainly interesting. It does not produce a significant amount of pollution, but given most of this occurs in the vicinity of the airport, is likely to have a reasonable benefit particularly in terms of the health aspect.
There were some concerns however. The authors need to be more clear and concise in explaining how such a system would work. When it would be "on", how much power/energy will it generate (at least to an approximation) and how will this be stored. The proposal neglects the weight penalty of carrying the turbine and batteries (presumably both similar in weight to an APU, if not heavier!), and is dismissive of the drag penalty that would probably occur from the device protruding out of the aircraft's body. Interestingly, there are periods of flight when this would be beneficial e.g. during the landing procedure, so if the proposal can outline how much energy could be extracted for a "typical" landing procedure, then it may outline the benefits much more clearly.
Congratulations! Your proposal, Cross Flow Air Turbine (CFAT) Auxiliary Power Unit in the Aviation contest, has been selected to advance to the Semi-Finalists round.
You will be able to revise your proposal and add new collaborators if you wish, from now until June 15th 2016.
We’ve also included ratings and feedback that will be posted to the “Evaluation Results” section of your proposal. Please incorporate this feedback in your revisions, or your proposal may not be advanced to the Finalists round. We also ask that you summarize the changes that you make on the Evaluation tab to help us understand what you have changed. Your proposal will be evaluated on what is on the description tab, so please make sure all new and updated information is included there. As you make revisions, we recommend you save an offline copy as a backup, as the site will log you off after 30 minutes.
- The APU accounts for around 5% of the environmental impact of aviation as stated by the author. The proposal impact is therefore not great, however it is an impact that could be solved. The judges felt that re-orienting the proposal to focus more on reducing the emissions due to the use of the APU would make for a stronger and more viable proposal than using the CFAT device.
- Unfortunately, it is not clear as to the aim of the CFAT and how it would practically reduce impacts. Firstly, the judges do not agree that the aerodynamic drag caused by the device in cruise would be small. Extracting any energy from the flow is going to have an impact on the power required. The only time that it may be useful is during landing. Secondly, the CFAT would be useless while the aircraft is stationary, when most of the APU emissions tend to occur. The only means to solve this impact is by storing the CFAT produced energy in batteries on board of the aircraft, which would increase weight and thus fuel burn.
- Overall, the judges felt that the proposal should turn its focus to the APU system emissions reduction rather than focus on the CFAT technology.
At the revision deadline listed below, your proposal will be locked and considered in final form. The Judges will undergo another round of evaluation to ensure that Semi-Finalist proposals have addressed the feedback given, and select which proposals will continue to the Finalists round. Finalists are eligible for the contest’s Judges Choice award, as well as for public voting to select the contest’s Popular Choice award.
Thank you for your great work and again, congratulations!
Jun 7, 2016
Thank you judges for selecting our proposal for the semi finalists round. We will give our best to match your expectations.
Here I want to point out that CFAT technology is still in ideation stage hence the design can be altered to obtain desired output and you will see the changes in upcoming revisions. Also, CFAT can be used while aircraft is stationary on ground. We have mentioned that it will also act as a Cross flow fan to move the large air of volume for air conditioning using the stored power. We will optimize our design as soon as possible and it will be more clear to you. Till then Cheers !
Thank you again !
Jun 12, 2016
We have updated our proposal in description tab. We took your points into consideration. Thank you.