PetitCessnaVoyageur wrote:
Do you all consider that the aircraft should be perfectly free of ice ? Or just account for some less performances ?
Unless you are being paid to be a test pilot, all the lifting surfaces should be clean. The difference that even a small layer of frost can make is actually quite astonishing.
Thanks @JasonC
This is what I chose to do, by education or/and instinct, but I wondered if I was a chicken or not.
You relieve me from that doubt 
For the little story, I saw a SR20 taking off with wings covered exactly the same frost layer (maybe a bit worse, as it was parked in the shadow) with one person on board. (and unknown fuel quantity).
It seemed to rolled forever (I estimate 800-1000m of rolling), which even for an SR20, sounded a lot (!!), with 1 person on board, 360ft above the sea, and 5°C OAT.
Climb was not impressive either.
30 minutes later, when it came back, wings were clean, so sublimation should be helped by airflow ! (it took 30 more minutes to get mine ice free)
For the little story, I saw a SR20 taking off with wings covered exactly the same frost layer (maybe a bit worse, as it was parked in the shadow) with one person on board. (and unknown fuel quantity).
It seemed to rolled forever (I estimate 800-1000m of rolling), which even for an SR20, sounded a lot (!!), with 1 person on board, 360ft above the sea, and 5°C OAT.
Climb was not impressive either.
Some would say he was damn lucky to get away with that, and should have known that this type likes wing contamination less than most other certified types.
PetitCessnaVoyageur wrote:
Do you all consider that the aircraft should be perfectly free of ice ?
The POH of the aircraft I fly at work has diagrams that show which parts of the aircraft must be completely free of ice, frost and snow. The fuselage is not among them, but the wings and empennage.
Or just account for some less performances ?
No. You can not know what penalty the frost will have on your performance!
I would not fly with the aircraft in your pictures. But from the look of them, only a brush is needed to remove the frost. Can be done in 10 minutes by a single person. And for the windscreen, I would use some deicing fluid because it gets scratched easily, even with a brush. One can take TKS fluid or the stuff for car windscreens, which is a lot cheaper, at least when purchased in small quantities.
For the little story, I saw a SR20 taking off with wings covered exactly the same frost layer (maybe a bit worse, as it was parked in the shadow) with one person on board. (and unknown fuel quantity).
It seemed to rolled forever (I estimate 800-1000m of rolling), which even for an SR20, sounded a lot (!!), with 1 person on board, 360ft above the sea, and 5°C OAT.
Climb was not impressive either.
30 minutes later, when it came back, wings were clean, so sublimation should be helps by airflow ! (it took 30 minutes more to get mine clean)
Wow, particularly in an SR20, with its very sensitive aerodynamics, that sounds completely mad to me.
what_next wrote:
But from the look of them, only a brush is needed to remove the frost.
You can remove the top, but there is under that a quite solid layer iced up.
boscomantico wrote:
Wow, particularly in an SR20, with its very sensitive aerodynamics, that sounds completely mad to me.
I was a bit anxious while looking at his take off too, but wasn’t sure why. Now I understand :-)
PetitCessnaVoyageur wrote:
You can remove the top, but there is under that a quite solid layer iced up.
If it is sufficiently thin (less than 1mm) and smooth, it should not pose much of a problem. But don’t quote me on that when you settle accounts with the insurer…
I promise :-)
The FAA changed its advice on removal of ice, a few years back IIRC, from saying that a thin layer of smooth clear ice is OK, to no ice allowed at all.
I think a thin smooth layer should be ok (looking at it purely aerodynamically) but it is awfully risky to give that kind of advice, especially when you get a certain % of people doing stunts like the above.
Also ice can presumably unbalance control surfaces, and cause flutter.
Peter wrote:
Also ice can presumably unbalance control surfaces, and cause flutter.
Any ice on control surfaces is an absolute no-no! But a thin layer of clear ice behind the first third (chord-wise) of the wing should be no problem for the typical piston single as the airflow is not laminar in that region. But again – don’t quote me.
