by VickersPilot » Wed Jan 06, 2021 7:58 pm
A few points regarding RACC (for now, I speak academically, CFIDave perhaps speaks practically above).
First the aircraft can be optimised to manage heat with easy gains:
The RACC sufficiency is the ratio of [Required BTUs] to [Available BTUs]. Since one can't increase the [Available BTUs], the key is to reduce the [Required BTUs]. I have personally used Kevin Duggan's JetShades and can attest they significantly reduce the greenhouse effect in an aircraft cabin. They also improve thermal stability - removing (reflecting away) the asymmetric solar gain means the aircraft cooling or heat can be evenly distributed. In summary, using JetShades will significantly reduce the [Required BTUs] and more importantly equalises the cooling or heat in the cabin.
Then we refer to the RACC supplement:
http://support.diamond-air.at/fileadmin ... S07-r1.pdf
A few abstracts:
- Takeoff Ground Roll +60m, Takeoff Distance +100m
- Time, Fuel, Distance in Climb +6%
- Rate of Climb -70ftpm
- Cruise - 10kts
Given the above are from the AFM Supplement, one assumes that is worst case (max load on AC). So reducing the load on the AC should in theory, perhaps not in practise, reduce the performance penalties. Further, you're only likely to use the AC at full load with temperatures that are well above ISA, so if one suffers the performance penalty, it's likely to be combined with a hot weather (density alt) penalty.
A few points regarding RACC (for now, I speak academically, CFIDave perhaps speaks practically above).
First the aircraft can be optimised to manage heat with easy gains:
The RACC sufficiency is the ratio of [Required BTUs] to [Available BTUs]. Since one can't increase the [Available BTUs], the key is to reduce the [Required BTUs]. I have personally used Kevin Duggan's JetShades and can attest they significantly reduce the greenhouse effect in an aircraft cabin. They also improve thermal stability - removing (reflecting away) the asymmetric solar gain means the aircraft cooling or heat can be evenly distributed. In summary, using JetShades will significantly reduce the [Required BTUs] and more importantly equalises the cooling or heat in the cabin.
Then we refer to the RACC supplement:
http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support/DA62/Airplane_Flight_Manual/Supplements/70125e-S07-r1.pdf
A few abstracts:
- Takeoff Ground Roll +60m, Takeoff Distance +100m
- Time, Fuel, Distance in Climb +6%
- Rate of Climb -70ftpm
- Cruise - 10kts
Given the above are from the AFM Supplement, one assumes that is worst case (max load on AC). So reducing the load on the AC should in theory, perhaps not in practise, reduce the performance penalties. Further, you're only likely to use the AC at full load with temperatures that are well above ISA, so if one suffers the performance penalty, it's likely to be combined with a hot weather (density alt) penalty.