Hot weather flying

[Jabiru7252]

So, who has been flying in this stinking hot weather? I didn't mind flying the Tobago about in hot lumpy weather but I find the Jabiru is thrown about too much for me to enjoy the flight. The temperature in my hangar probably exceeded 50 degrees, I'll check that tomorrow.

 

 

[Ultralights]

Sadly can't fly jabirus in temps above 40degC. In the POH, we'll is in the LSA models and early 170's. Savannah loves the hot weather. Claims a bit less, down from 1000 ft/min to about 700 when it's 42degC.

 

 

[Stoney]

The wonderful pilots of the water bombing aircraft and their spotters, both fixed wing and rotor, helping to keep us safe from bushfires.

 

I spent the day with the farm fire fighting equipment hooked up and ready, liaising with the neighbours and monitoring the three fires within a few kilometres. I was watching the firebombers come and go and listening to the sometimes frantic calls on the CFS radio, feeling the wind changes on the back of my neck and wondering how hard it would be on the pilots.

 

On days like today, I don't have to fly, nor do I want to. I am very grateful to those that do.

 

Whoever you guys are, a very heartfelt thankyou, I salute you. Gary

 

 

[rgmwa]

We had the fire-fighting helicopters, the Erikson Skycrane and a couple of others, flying at tree-top level over our house for several hours last Sunday during the Parkerville bushfire in WA. They were drawing water from a large dam just across the road and dumping it on the fire front, which got to within about 2 km of our place before the wind shifted. In fact we evacuated at one stage, but returned later. Their circuit time was only about 5 minutes. Those pilots are very good. They have to maintain high levels of concentration for hours while flying at low level in hot and turbulent conditions, and in close proximity to other aircraft. Hats off to them. They do a great job.

 

rgmwa

 

 

[Oscar]

Sadly can't fly jabirus in temps above 40degC. In the POH, we'll is in the LSA models and early 170's. Savannah loves the hot weather. Claims a bit less, down from 1000 ft/min to about 700 when it's 42degC.

I do not see this limitation in either the J120 or J160 POH, can you please provide the wording of this limitation in the POHs you referenced?

 

 

[ayavner]

9 CLIMATIC RESTRICTIONS

 

Maximum Ambient Operating Temperature................38°C

 

Flight into known icing conditions ............................... Prohibited

 

From the 170C POH

 

 

[ayavner]

and from the J160POH:

 

Extrapolation outside the boundaries of the Take-Off Distance Table is not permitted. When the outside air temperature and/or pressure height is below the lowest range included in the table, the aircraft performance shall be assumed to be no better than that appropriate to this lowest range. The performance information is not valid when the outside air temperature and/or pressure height exceeds the maximum values for which this information is scheduled.

 

The chart only goes up to 38*

 

So i think its "implied" in the 160 POH, then "stated" in the 170 POH for clarification. If extrapolation is not allowed, then above 38* sounds like a no-go.

 

 

[shu77]

The Tecnam isn't buffeted anywhere near as much as the Jabiru, but I have been noticing a lot more engine management is required in the recent conditions. Full throttle climbs that I normally would have completed without a second thought have the oil temperature creeping up through the yellow band requiring a mid climb cruise to let everything cool back down and even cruise needs to be managed a couple hundred RPM slower than I would in July. Not to mention the temperature gauge still showing >20 degrees when sitting at 4500 ft. The experienced guys tell me they don't bother this time of year and wait until it gets cooler.

 

 

[Oscar]

and from the J160POH:Extrapolation outside the boundaries of the Take-Off Distance Table is not permitted. When the outside air temperature and/or pressure height is below the lowest range included in the table, the aircraft performance shall be assumed to be no better than that appropriate to this lowest range. The performance information is not valid when the outside air temperature and/or pressure height exceeds the maximum values for which this information is scheduled.

 

The chart only goes up to 38*

 

So i think its "implied" in the 160 POH, then "stated" in the 170 POH for clarification. If extrapolation is not allowed, then above 38* sounds like a no-go.

Well, thanks for that. Most interesting; no such climatic limitation statement appears in the J120 POH. The ambient temp. limit for the 170 suggests some sort of structural reason, whereas the statements for the 160 seem to me to be more a 'this table of performance is only valid between these limits', rather than a specific injunction that the thing can't be flown if ambient exceeds 38C. Certainly worth finding out more information if you are a 170 owner, for sure!r

 

 

[shafs64]

In good old QLD its just better to go in the morning

 

 

[jetjr]

Has been discussed before, is to do with curing temps of the fibreglass, when new the 40 deg lomit is important

 

Ill also say performance is pretty ordinary and temps do get out of control and they dont want to climb much.

 

The rough conditions only really come into play after midday mostly and can calm down by 1800 so leave early, fly high and slow down in descents in these bad times. There sure are days when i washed i hadnt decided to fly

 

 

[Oscar]

Has been discussed before, is to do with curing temps of the fibreglass, when new the 40 deg lomit is importantIll also say performance is pretty ordinary and temps do get out of control and they dont want to climb much.

The rough conditions only really come into play after midday mostly and can calm down by 1800 so leave early, fly high and slow down in descents in these bad times. There sure are days when i washed i hadnt decided to fly

The minimum quoted Glass Transition temperature for lc3600 cured at 25C ( i.e. fairly much ambient for Jabirus since the minimum construction temp is normally quoted at 24C) is 50C, so there's a fair bit of margin there. Certainly it's the reason why nothing other than white is acceptable on the upper surfaces. Perhaps Jabiru are becoming very conservative (and they have always been reasonably conservative in all their performance claims, relying on only properly conducted tests to required flight test specifications), but I'd not be surprised if the reason has more to do with maintaining an acceptable climb performance than simply structural reasons.

 

 

[alf jessup]

Flew on Tuesday late afternoon in Victoria 40 plus degrees during the day. Sea breeze came in but still 30 plus degrees at 1500 and 2500 feet but the air was like glass with not a bump in it.

 

Flew again Wednesday afternoon 37 degrees at 1000 to 2500 feet and still not a ripple in the air, climbed out at about 85 knots to manage the temps and never got out of the green

 

Surprised me how smooth the air was with such warm air temperature t these altitudes.

 

Alf

 

 

[Guest Nobody]

The minimum quoted Glass Transition temperature for lc3600 cured at 25C ( i.e. fairly much ambient for Jabirus since the minimum construction temp is normally quoted at 24C) is 50C, so there's a fair bit of margin there. Certainly it's the reason why nothing other than white is acceptable on the upper surfaces. Perhaps Jabiru are becoming very conservative (and they have always been reasonably conservative in all their performance claims, relying on only properly conducted tests to required flight test specifications), but I'd not be surprised if the reason has more to do with maintaining an acceptable climb performance than simply structural reasons.

It's pretty easy to have a surface temp that is 20 degrees above the ambient if the surface is in the sun.

 

It's surprising that they don't use a post cure heat treatment to improve the elevated temperature performance of the resin.

 

 

[Garfly]

Stoney wrote: "The wonderful pilots of the water bombing aircraft and their spotters, both fixed wing and rotor, helping to keep us safe from bush fires … Whoever you guys are, a very heartfelt thankyou, I salute you."

 

Well, I hope it's not talking out of school to reveal that one of those flyers is our own (rather shy) "Student Pilot".

 

Go figure! …. with something like 25,000 hours at the stick you'd think ol' Stude would have graduated by now, no?

 

(Okay, he does run out of fuel occasionally - but only in his vintage Land Rover ;-)

 

 

 

 

[DrZoos]

Generally speaking in most of Australia white surfaces will increase between 5C in winter to 14C in summer over ambient temps.

 

So most jabs in most areas should be ok up to 36C ambient in anything but extreme UV. Anyone living in the higher UV southern areas may need to adjust for higher UV especially if parked at altitude in the heat.

 

 

[motzartmerv]

Yes, a good time to think about the effects of temperature and air pressure on the way ANY aeroplane performs.

 

There are 3 main problems with high temps.

 

* The Air being less dense (as temp increases, density decreases). Wings need air to work. the less of it there is, the less lift the wing will produce.

 

*The engine will be sucking air that is less dense and mixing it with the fuel. this will cause a reduction in engine performance

 

* The propellor also relies on the density of the air. With every revolution of the prop there is less air being pushed back, therefor, less thrust is being produced.

 

Bit of a 3 pronged attack. The important thing to remember is that when operating marginally, ie, from short and or high elevation airfields, that you really have think about how you expect the plane to perform. just because you have taken off from there before is in NO WAY a garuntee it will work today!!.

 

 

[robinsm]

lumpy hot weather, good for developing bump tolerance...

 

 

[robinsm]

Lumpy hot weather, good for developing bump tolerance....!!

 

 

[Oscar]

Generally speaking in most of Australia white surfaces will increase between 5C in winter to 14C in summer over ambient temps.So most jabs in most areas should be ok up to 36C ambient in anything but extreme UV. Anyone living in the higher UV southern areas may need to adjust for higher UV especially if parked at altitude in the heat.

Since Jabiru have used ambient cure lc3600 resin since they started producing aircraft and there have been no wing or fuselage in-flight structural failures as far as I am aware, I think it's a fairly safe bet that the lack of environmental limitations on flying in above 38C is not related to a structural issue.

 

 

[ayavner]

my understanding based on the wording is that it is related to the takeoff/landing performance, ie they won't guarantee and one shouldn't assume/extrapolate that you can safely take off or land if the temp is over 38.

 

 

[dazza 38]

I have a density altitude App on my iphone . Its free and a great app. Go to the apple store and type in density calculator. If you dont have a iphone sorry i cant help you :)

 

 

[motzartmerv]

Lol..You will then need to use maths!!!!..DOH!!!!

 

 

[dazza 38]

No maths involved if you are close yo s airport, just press one key and it down loads the current information. At home it picks coolangatta which is 15 kays from home. When at Boonah where i fly from, it uses Amberley which is close enough. Cool stuff, i showed my CFI and he loved it and down loaded it himself.

 

 

[DrZoos]

Since Jabiru have used ambient cure lc3600 resin since they started producing aircraft and there have been no wing or fuselage in-flight structural failures as far as I am aware, I think it's a fairly safe bet that the lack of environmental limitations on flying in above 38C is not related to a structural issue.

I beg to differ. When i was going to buy a jab , i rang and spoke with the sales manager about this exact issue. His response is its due to the softening of glues and resins softening.