UL aircraft Limitations

[NWpilot]

Hello All,

 

I need a bit of a hand, I am really starting to get serious to get myself a UL AC, My biggest concern is where i live, Up here in the Pilbara, it is not unusual to be high 30's, low to mid 40's. now i have read somewhere about the Jab engine i belive it was, that it only likes a ??min time full power at ?? degs ambient temp, i think it was mid 20's or mid 30's. Now, i dont think i would be able to even climb out on a warmish day up here, due to the specs of the engine, does anyone know of a AC or engine that i could use up here with out having to worry to much about putting to much stress on it. i fly a c-172 up here no dramas but not sure about the UL world. Or should i be looking at putting a twin or larger oil cooler on the AC?

 

really confused and any help will be appreciated.

 

Thnaks,

 

 

[Thx1137]

Max ambient temp for a j160 is 38 degrees which is in the aircrafts POH. I don't know about the other models however you could download the handbooks from the jab site, they will tell you.

 

I think the SportStar would do better, I haven't seen a max temp listed so with those i think it is limited by whether the engine can stay cool enough and how much you would cook under the bubble canopy!

 

Steven.

 

 

[Guest basscheffers]

I think the SportStar would do better, I haven't seen a max temp listed so with those i think it is limited by whether the engine can stay cool enough and how much you would cook under the bubble canopy!

I have flown mine in 40+ without problems; that's where the liquid cooling of the Rotax probably really helps! It also has a rather well working oil cooler. Low (below green) is the norm and it is not an issue. On a stinking hot day, you might get it into the green on a long climb. I have seen it halfway into the green once! :D (38 degree day climbing to 8500')

The canopy is only really an issue while taxiing; once you are airborne you have plenty of airflow. Just don't forget your sunscreen!

 

 

[facthunter]

Max temp in POH.

 

Most aircraft POH's stop at around 40 degrees. This doesn't mean that the plane won't fly above those temps and with RAAus I would consider that a realistic and cautious/ conservative appraisal of what the plane would do (with the pilot taking responsibility) would be the way to go. It certainly won't lift as much and you will use more runway. I have been at Alice Springs and UNABLE to go because of the OAT. (Legal situation applies with RPT.)

 

I know a bloke who regularly flew a J430 up the centre. While this was no homesick angel on a hot day, the J230 is essentially the same plane with less payload. When the temps elevate use higher climb speeds, to help the engines cooling. I believe a Jab set up properly will handle the high OAT's engine wise. Air cooled engines are OK in high ambients. The rate of heat transfer is proportional to the temp change engine to ambient, so while it will run hotter, it is not terminal. in theory at least the engine should only get hotter by an amount not much above the ambient increase. ( allow for a slightly reduced MASS of cooling air due to temp rise).

 

The same applies to a liquid cooled engine with the added problem that the boiling point of the coolant is controlled by the additives and the pressure acting on it. (The radiator cap plus ambient pressure). IF you exceed the boiling point you will lose coolant and/or get steam pockets in the engine. Nev

 

 

[NWpilot]

Hello All,

 

thanks for the info provided, it all helps out.

 

I think i will really have to pick my days in Summer. I think a bit more research is in order for me.

 

Once again, Thanks for all your help