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Hot weather flying


Jabiru7252

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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.

Interesting then that Jabiru haven't added anything similar to their 120 and 230D POH, yet they're the same resin.

 

 

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Interesting then that Jabiru haven't added anything similar to their 120 and 230D POH, yet they're the same resin.

Resin and glues was his answer and there was absolutely no ambiguity in his response. It was direct to the point. I initially asked was it due to engine overheating or performance and got a resounding no.

 

 

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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 :)

Thanks for that Daryl, just downloaded it.

 

 

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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.

I've had two flights recently on quite warm days. One was lovely and calm and relaxed and made me fall in love with flying all over again (apart from having to manage the temps on climb. Ah well), while the other was so turbulent that I hit my head on the canopy 3 times in the last 5 miles. Very, very glad to get down on that particular day!

 

 

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heat of combustion couldnt get aways ... huh that what happened to me yesterday and many other truck drivers at about 4 pm on toowoomba range hwy. first time i my life i have red lined any engine but i wasnt alone ...there were trucks ducking and diving into laybys to cool off all up the road.

 

 

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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

Maybe we need a thread on water bombers, Stoney.

 

I spent much of yesterday and last night at a fire on a neighbour's. Water bombers, several RFS units, a grader and farmers on quads.

 

Came away very impressed with the young volunteers in their huge RFS vehicles, weary and blackened from a long day on the fireground. It occured to me that they are probably of similar calibre to the young people we sent off to wars past. Young, but showing maturity beyond their years.

 

 

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Maybe we need a thread on water bombers, Stoney.Came away very impressed with the young volunteers in their huge RFS vehicles, weary and blackened from a long day on the fireground. It occured to me that they are probably of similar to the young people we sent off to wars past. Young, but showing maturity beyond their years.

Too right OK. My son is 21 and has been a CFS volunteer since he was about 15. He has been a triple zero operator for 2 years and is in the army reserves. I have to admit he is a lot more mature than I was at his age, I was all bones and balls, no brains at all. (My how things have changes, I'm not bony anymore!) I am so proud of the independent, confident and caring man that my little boy has turned into and I believe that the CFS has been a big part of that. These guys and girls really deserve our thanks and respect. I think Australia would be a better place if it were mandatory for all young people to do a couple of years of some sort of community service.

 

 

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Too right OK. My son is 21 and has been a CFS volunteer since he was about 15. He has been a triple zero operator for 2 years and is in the army reserves. I have to admit he is a lot more mature than I was at his age, I was all bones and balls, no brains at all. (My how things have changes, I'm not bony anymore!) I am so proud of the independent, confident and caring man that my little boy has turned into and I believe that the CFS has been a big part of that. These guys and girls really deserve our thanks and respect. I think Australia would be a better place if it were mandatory for all young people to do a couple of years of some sort of community service.

What a wonderful young bloke you have, Stoney.

I have few fond memories of my previous existence in schools- except the wonderful kids. I found that for most kids, the more you trusted them with responsibility, the better they got.

 

Re those RFS volunteers, one young bloke was battling along with a bad limp. He has a painful and debilitating injury, but has to wait months for an op. Meanwhile, the media concentrate on all the minor injuries to our footy players and cricketers- who get immediate treatment.

 

 

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Fresh FRP softening has always been the response from Jabiru re 40 deg temps. As it ages it becomes less of a problem.

 

Dont miss an opportunity to criticise them Zoo's

 

Reality is engine temps arent sorted very well in many AC and this presents as a limit often before 40 deg ambient limit.

 

 

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My Libelle handbook agrees with you jetjr. On the subject of "hot trailers" it says not to worry, an even warming is like a tempering action, the limit of full load will always go a little higher.

 

Of course, this does not negate all the effects of lower air density. You could calculate a reduced weight limit for a particular temperature and height to maintain a safe take-off distance, but in the meantime I reckon a 2 seater flown solo would normally be ok.

 

 

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Having tried it once, an issue i saw was the lack of ambient cool down with altitude, still carrying 35 degrees at some height knocks the power out of the engine and i have been at 3000 ft with little climb capability. Add this to overheating and you can get in a place difficult to get out of.

 

Look at DA calcs sees similar conditions at 3000 as would be seen at 6-7000 normally

 

Also looking at take off performances you can double them easily in very hot weather.

 

 

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Connellan's used to operate DeHavilland Rapides out of Alice Springs in the 1950's. The outstation strips were short, the Rapides short on power and the airfield density altitudes high. I certainly remember one of them in the trees at the end of Hermansburg runway after a failed take-off, but I don't know if it had been loaded up with medical staff and a patient or not.

 

Getting back to the Libelle, there is a graph in the handbook showing how the temperature for full load increases with storage temperature , up to 57 degrees full load allowable if the storage temperature was 80 degrees. Thats hot.

 

 

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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.

Could be engine approaching detonation limits, elasticity of airfame approaching flutter limits, reduced stiffness of spar boom approaching buckling limits, reduced atmospheric density exacerbating prop compressibility... the GTT is not a magic number, it is a critical boundary; then little thangs in the plastic change their nature before the GTT is reached, and there are other considerations (as listed, plus probably a few i ain't thunk of).

 

 

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