mh wrote:
No, I am just constantly amazed about the items supposed to be impossible on certified aircraft
I didn’t say that. The thing is, on uncertified aircraft you can just mount a heater around the exhaust, no questions asked. This is assumingly (by me) done on the C42, and with the further assumption that good heating in the cabin is a decision/design by the aircraft manufacturer, and has nothing to do with the engine. Which again is exactly what I wrote (for uncertified aircraft), only in other words.
To my knowledge (I could be wrong of course, but still), Rotax does not have any exhaust systems with heaters on them, except probably for carb heat. But even for carb heat I have seen liquid based heaters, not hot air from the exhaust, although I think I remember I have heard about it.
So, I wonder, is the exhaust system part of the engine, or part of the aircraft. To my knowledge Rotax don’t allow anyone to interfere with the engine, not even uncertified ones. People still do it of course, and Rotax say by doing this, your warranty is void, and you cannot call it a Rotax anymore (as if anyone cared 
) Anyway, IMO it is still a valid question for a certified aircraft with a certified engine. Is the exhaust part of the aircraft, or part of the engine ? If it isn’t, then it’s simply a poor design choice of the aircraft manufacturer not to mount a proper heater, but if it is, then how can you mount a heater without drawing Rotax into it?
The EV-97 eurostars I have flown all have a shroud around the muffler box to supply cabin heat and again I would say this heater was as good as any I have flown on any lyco or continental.
All Rotax engines provide cabin hot air from a shroud mounted around the exhaust.
For the cold sensitive, the Aeropro Eurofox heater boost kit, teed into the liquid coolant lines will augment exhaust heated air with coolant heated air for four hundred dollars and change.
T28 wrote:
All Rotax engines provide cabin hot air from a shroud mounted around the exhaust.
None of the ones I have flown. It’s a separate little air/water heat exchanger like the ones mounted in cars. Works great in +15 and up
T28 wrote:
Aeropro Eurofox
I guy just called me some minutes ago, he had bought a Eurofox and wanted a check ride and some short field practice Looking forward to that.
Can’t blame Rotax if the kit installer went for the el cheapo version without exhaust shroud then can you… EGT in a Rotax is the same as in a Continental or Lyc. If the shroud assembly doesn’t provide enough heat for a two-seater (unlikely) maybe the kit assembly quality is to blame… (too many holes, doors / cockpit seals lacking).
Exhaust shroud on our Eurofox’s 912.
Exhaust shroud on the Bristell (UL and CS23)
T28 wrote:
too many holes, doors / cockpit seals lacking
We have an old Cub from the 40s. It leaks all right, but the heater do the job no matter what. On the P2008, 2-3 years old now, we have had an electric heater in the cabin, going continuously for the last couple of months to have some residual heat in there for the occasional local flight (in -15 to -20 ).
So maybe time to delete the 212 liquid heater option and go back to the exhaust shroud standard option that works perfectly well…
As a sidenote complaining that the Rotax “isn’t appropriate for winter ops” by comparing it with the thermal output of the Cub engine is a bit apples to oranges.
T28 wrote:
As a sidenote complaining that the Rotax “isn’t appropriate for winter ops” by comparing it with the thermal output of the Cub engine is a bit apples to oranges.
I didn’t do that, which I’m sure you have noticed. My club has 4 Rotax powered aircraft. Below -10 to -15 none of them is capable of heating up the cabin – at all. I call this an Apple (only) assessment (or real world experience if you want). We also have 4 Lycoming and Continental (Cub) powered aircraft. All of them works perfectly well with temperatures below -10 to -15. This is an Orange (only) assessment. Comparing those apples with those oranges is perfectly valid, and the result is as it is.
As I said, the liquid heaters in those Rotaxes are adequate for summer operations (+10 deg and up. Works below that as well, but not if you want +20 in the cabin and there is no heat from the sun to speak of). The exhaust heaters sounds interesting, but I have yet to see any real world experience in temperatures below -10 to -15. In theory they should work just fine, but no hard data is available.
