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Hot weather/crap performance

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Hot weather/crap performance

Old 10th Jul 2014, 22:21
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Hot weather/crap performance

It amazes me how much performance is degraded now the hot weather (23c today) is here, you get used to takeoff points, climb out rate and landing distance at your home field then along comes a scorcher of a day with no wind and all of a sudden your thinking " WTF have I lost a mag or left the brakes on" or when landing, I always make every landing a short field, but short final ground speed is noticeably faster and roll out would not win me any prizes at the Alaska STOL contest.

Never thought I was say this but roll on the cold, crisp, clear sub zero winter weather.
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Old 10th Jul 2014, 22:45
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roll on the cold, crisp, clear sub zero winter weather
Yes. Sunny beaches and (sub-)tropical temperatures may look nice when being flown to them - for actually flying i.e. piloting an aircraft the criteria are quite different. I did my most beautiful flight (still a student, flying under tuition then) in February, the runway covered in two or three inches of snow.

The one type of weather one doesn't want for either, though, is what we are getting right now - low clouds and plenty of rain falling out of them. and lots of wind too. Bah, they used to call this summer...
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Old 11th Jul 2014, 05:46
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Hot weather/crap performance

23C is hot?
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Old 11th Jul 2014, 06:06
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23C is hot?
It is where piperboy84 flies

If it gets any warmer he might take off his simmet
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Old 11th Jul 2014, 06:26
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Had to look up that simmet thing, ETOPS. Thanks - my horizon has been expanded

I really look forward to the cooler months here in Oz, at least from a flying perspective. Just being able to fly in 23C (and below) rather than 35-40C makes a nice change. From a density altitude point of view we're not usually as badly off as folks in parts of the US, where high terrain and high temperatures really conspire against you and your aeroplane.

Nearly all my pleasure flying in summer is done in the early morning, before it gets too hot and the atmosphere starts to get lumpy. Might as well be in the office (or preferably at the beach) then.
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Old 11th Jul 2014, 10:55
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Or replace it during the hotter "weeks" with a Rab C.
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Old 11th Jul 2014, 12:22
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I've noticed this too. Our temps have gone from -30 in the winter to + 30 in the summer. The rate of climb I'm getting from the poor little R model 172 is horrible at the moment.

We are at 250ft above Sea level but already I've seen density altitudes of 1800ft

I'd just about got my forced approaches nailed but now I feel like I'm back to square one with the altered glide characteristics in the hot air, with all the thermals and updrafts to contend with

I'm off to spend an entire flight this afternoon trying to nail those forced approaches. At the moment they are pretty much all that is keeping me from my flight test.
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Old 11th Jul 2014, 13:52
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You should try a worn out Cherokee out of Albuquerque at 35c. It nearly becomes a single seat aircraft.
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Old 11th Jul 2014, 16:53
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Or a 172 from Tinson Pen, four up ... used most of the runway(!) and then took forever to just about manage to stagger up to 3,000'.
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Old 11th Jul 2014, 17:26
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I thought the trees at Kingsmuir grew an extra four feet on hot days.
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Old 11th Jul 2014, 18:23
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A typical winters day in Johannesburg

Air temperature 26.1C
Dewpoint temperature -4.2C
QNH 1023
Field elevation 5327ft
Density altitude 7514ft

Summer is more interesting with temps in excess of 30C
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Old 11th Jul 2014, 22:19
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What VH-UFO and others have said. 23C is nowhere near hot!

I guess the reason I keep visiting this forum is that it is often good for a laugh

However there is a valuable message in all of this. High density altitude can be a killer if you don't do your sums. That was drummed into me when I did my PPL theory in Australia.
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Old 12th Jul 2014, 09:06
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This may not be a real density altitude problem compared to the tropics but when we up this far norf are used to temperatures in single figures we can notice a difference on a "scorching hot" day. But, good laugh to you guys that fly from 5000ft strips! Can't do smilies on this thing!
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Old 12th Jul 2014, 09:44
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To our antipodean friends: it's well known that British centigrade is hotter then Oz centigrade.
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Old 12th Jul 2014, 10:25
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Never had a problem flying my Supercub in Texas, before boxing it up for the move to the UK. But then it really does come down to performance, doesn't it? Power to weight, lads, power to weight!

The only problem with flying a 150 hp Supercub in the UK is remembering NOT to enjoy max climb out of Wellesborne, and finding myself nose to tail with somebody doing that peculiar overhead join you Limeys employ....what's wrong with joining downwind?
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Old 12th Jul 2014, 17:13
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The only problem with flying a 150 hp Supercub in the UK is remembering NOT to enjoy max climb out of Wellesborne, and finding myself nose to tail with somebody doing that peculiar overhead join you Limeys employ....what's wrong with joining downwind?
"When in Rome, do as the Romans do"
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Old 12th Jul 2014, 19:52
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what's wrong with joining downwind?
because


and finding myself nose to tail with somebody
in the downwind......
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Old 13th Jul 2014, 07:53
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Try flying out of Ryiadh Saudi Arabia in July.

48 degrees C with dust in a AC685 over gross.

Book figure was 4,000 feet. I reckon we did 6,000 feet ground run

Like others from OZ we are all taught the effect of temperature on performance. Australia doesn't have too many runways above 3000 feet altitude, but inland temperatures are usually between 30 and 40 degrees.
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Old 13th Jul 2014, 08:32
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Reading the books ?

All this thread seems to prove to me is how few people have properly digested the contents of the flight manual.
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Old 13th Jul 2014, 09:36
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It would be nice to have a Flight Manual to digest. I have a few notes with VNE and max rpm, but no performance figures.
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