Hot weather flying

[Guest Kevin the Penniless]

I fly a Jabiru J170 and most would be aware it has a high wing with strut. This makes it very rigid and I find it can be quite horrible when you 'hit a bump' while flying in hot weather. Imagine driving your car at 60km/hr up over a gutter - that's the sort of bumps I was experiencing and I was convinced the wing bolts were going to shear. That and the fact the plane was all over the place like a cat on fire made for quite fearful flying. Anybody else experience the same 'dread' while in the air on 30 plus degree afternoons? (Or am I just a wimp?).

 

 

[Guest rocketdriver]

Hi Kevin

 

Yes, it can be quite uncomfortabel at times .... but as long as you are flying at a speed less than the yellow arc on the ASI, you won't overstress the aircraft ..... if you hit a really strong bump, the aircraft will stall before it is overstressed. Also, the slower you fly, the less uncomfortable the bumps will be ......

 

cheers!

 

RD

 

 

[Guest Maj Millard]

Rick P, I think your comfort level is purely dependant on the machine your in. When I ferried a Savannah VG in central Qld middle of the day heat turbulance, I did find myself backing off a bit at times. The savvy struts are the same exact extrusion as the landing gear struts on the Slepcev storch, even though I know the Savvy wing strut set-up is far stronger than it needs to be.

 

The lightwing I fly is very strong, I'm often close to gross, and it's way over-built for the job it does. Mostly AN-5 or 6 bolts holding on the wings and struts, so I'm not real worried about shearing bolts. I have seen AN-4 bolts sheared clean from crash forces in the past, which opens your eyes a bit, so I don't mind seeing a thicker bolt in critical areas. I have endured lots of severe turbulance in it, in places where I certainly wouldn't take a gazelle or Skyfox for instance, for fear that those airframes may not be up to the job.

 

The majority of aircraft designers do design critical airframe components with a higher load factor than normally required, which is probabily why there are not too many wing failures these days.

 

Another real danger is where an owner or builder drills out a critical wing attach fitting to take a larger bolt, thinking he is making the whole thing stronger. He has in fact weakened the fitting, and therefore the whole aircraft by doing so..........................Maj...

 

 

[Guest davidh10]

There's plenty of people who fly only early mornings or evenings in the hot weather due to the bumps, but I find that the experience is very subjective and varies not only between different aircraft, but also among different pilots. Perhaps the best approach is judged by whether you are enjoying the flight. It's one thing to be a commercial pilot and have to fly for the job, regardless of the conditions, but if you are flying for fun and not enjoying it, then avoid the source of the non-enjoyment.

 

 

[facthunter]

Turbulence due to high surface temps is UNPLEASANT for any one. Flying up the centre in summer is no fun below the inversion level and THAT rises to about FL130 in the mid afternoon. Your plane does get loaded dynamically, but the flexibility (or otherwise ) of the wings won't make a lot of difference. If the planes wing loading is low they tend to lack what is known as penetration and feel the bumps more acutely. Slowing up is the way to go and dont apply rapid elevator corrections to hold pitch attitude too precisely, Get the nose back to the normal position gradually. IF you had a "G" meter you would find that rarely would you see more than a bit over 2 G, in these circumstances. It is more dangerous at low levels on the downwind side of hills/mountains when the wind velocity is up a bit. Nev

 

 

[farri]

the sort of bumps I was experiencing I was convinced the wing bolts were going to shear. That and the fact the plane was all over the place like a cat on fire made for quite fearful flying. Anybody else experience the same 'dread' while in the air on 30 plus degree afternoons? (Or am I just a wimp?).

Kevin, I doubt that you`re a whimp,a whimp wouldn`t be up there in the first place.

 

This is a scientific fact and every pilot needs to understand it.............There are only two fears that each and every one of us is born with, one is, the fear of loud sound/noise, and the other is, the fear of falling, both of which remain with us for life, and the best we can do, is to learn to controll them.

 

I understand exactly what you`re talking about,and in my opinion, when the aircraft is jumping around, all over the place, it`s the fear of falling that takes over.

 

If this is what`s happening to you, when this occurs,focus completely on flying the AC. Conciously think about what you need to be doing at that precise moment,( make sure your airspeed is correct, the nose attitude relative to the horizon is correct and so on).Talk yourself through it, out loud,if you need to, this will help take your mind off the the fear. Fear needs to be kept in total controll or it could lead to disaster.

 

Keep in mind that turbulance is not only a result of temperature, we can find it anywhere at any time, and due to the light weight aircraft we fly, we`re going to get thrown around at times,we just need to learn to deal with this.

 

Frank.

 

 

[PapaFox]

Sometimes when I'm not in a particular hurry to get to the destination, if the bumps are being just a bit too uncomfortable, I just throttle back to idle and ride the thermals. Suprising how well some of our aircraft will thermal. Climbing at 1000ft/min with the engine idling is quite amusing

 

 

[Guest davidh10]

... I just throttle back to idle and ride the thermals. Suprising how well some of our aircraft will thermal. Climbing at 1000ft/min with the engine idling is quite amusing

I must admit that I've been tempted on a couple of occasions, to try this, but at the time I had a PAX on their first flight, so didn't. One day, however, when the right conditions present themselves and I don't have a first time PAX, I'm interested to see if it is possible in a trike. Best rate of glide with engine at idle approaches -1,000fpm at 55kn, but on a number of occasions, I've flown through a thermal that has been taking me up at 1,100 to 1,200fpm while in a level flight configuration, so in theory, I'd still slowly gain altitude.

 

 

[Guest rocketdriver]

Hi David

 

If you centre the thremal, you might well find 10 or 15 kts vertical available to offset your sink. I used to do this when towing gliders ..... couldn't turn tight enough (due to needing to keep the glider lined up behind!) to get anywhere near the core, but often increased the climb rate from about 500 fpm to well over 1000 fpm .....

 

RD

 

 

[Guest davidh10]

Thanks RD.

 

It will be interesting to see. Of course, the sink rate I quoted is in level flight and will increase substantially in a steep turn (hence steep esses to lose excess altitude on a glide approach).

 

 

[Thx1137]

Wimp? Nah. As long as your not incapacitated by it!

 

It reminds me of a time when flying 1000 feet below class c airspace. I was getting bumped around a lot so I was flying a little slower than usual. I felt this almight jolt and swear I gained 700 feet in less than a couple of seconds! I definately remember saying something like "oh dear!". It was a bit of a shock. :-) I am not worried about falling out of the sky as long as I have height, am not too fast, lunch wants to stay down and where I want to land isn't so unpleasent!

 

The only thing that makes me fearful in the Jab is trying to read the darn fuel gauges in any kind of bumpy weather and the fact that dipping the tanks is useless!

 

Steven.

 

 

[Catsy]

Fly early morning or late afternoon to avoid these dreaded "bumps" :-)

 

 

[poteroo]

Hi KevinYes, it can be quite uncomfortabel at times .... but as long as you are flying at a speed less than the yellow arc on the ASI, you won't overstress the aircraft ..... if you hit a really strong bump, the aircraft will stall before it is overstressed. Also, the slower you fly, the less uncomfortable the bumps will be ......

cheers!

 

RD

actually, Vno (low end of yellow arc), is too fast. You need to be using Va,(max manoeuvring speed). A rough calculation of Va is to take your clean stall speed and x it by 2. So, Va will vary with weight. At max weight, aircraft can handle turbulence at higher speed. Sometimes your range of Va speeds can be as much as 15 KIAS.

happy days,

 

 

[Deskpilot]

Hey Kevin, remember we can go to 10,000' now and generally, the higher you go, the smoother it gets (don't quote me ) I often find that it's a lot better at 3000" AGL than at 1500'.

 

 

[Chris Tarran]

Definetly not a wimp Kev. I did my solo nav exercise on the Eyre Pensinsula in those sort of conditions and there was a lot of nether region tensioning moments. On the inland legs I had to be up at 8500 (going west) or 7500 (east) AMSL to take the edge of the bumps. Even on the westerly coastal leg where the air was coller and less affected by thermals 6500 AMSL was the go. I did what a few here have advised and slowed the aircraft to below manouvering speed and instead of doing a touch and go at Wudinna did a full stop and had a rest and a calming cigarette. Had to make some adjustments to my flight plan but that was no hardship. Cheers Chris

 

 

[kgwilson]

When I flew Hang Gliders the bumps were good as they indicated lift so the trick was to try and stay in the bump. These were thermals. Columns of warm air rising through areas of cooler air. They are generally born on the ground as a bubble of warm or hot air and once the surface tension is unable to keep them there they break free and rise. Cooler air rushes in to take place of the warm stuff that has risen and the process continues. The trick was to find the core of the thermal which is where the air was ascending the fastest. Your variometer (like a VSI) indicates the area of strongest lift. I often had the needle pegged at 1200 fpm up with the audio screaming at its highest pitch in the core of a thermal.

 

The difference when flying a powered aircraft going from A to B is that you fly straight through these thermals and they appear as bumps. Also when a thermal become quite strong there is often air descending on the outside of the thermal and a vertical shear is created. Normally though when this happens a cumulo-nimbus cloud has developed at the dew point height (cloudbase) and the vertical winds inside the cloud can be extroadinarily strong in both directions. When rain forms it gets sucked back up & freezes & in the worst storm cells ends up going up and down multiple times getting bigger & bigger before smashing everything to bits when its weight is too much and gravity takes over and it hits the ground as cricket ball sized hail.

 

This is why you must always stay well clear of cloud especially cumulus. Normally though bumps are not dangerous just uncomfortable unless you really want an exciting ride & turn your RA aircraft into a glider

 

 

[Guest davidh10]

...This is why you must always stay well clear of cloud especially cumulus. Normally though bumps are not dangerous just uncomfortable unless you really want an exciting ride & turn your RA aircraft into a glider

I have occasionally encountered changes in vertical airflow that caused the aircraft to descend faster than me for a second or two. There's no doubt about it. It can be disconcerting.

 

Small Cumulus not so bad, just a bit of cloud suck, but CB or TCU, beware!

 

https://www.youtube.com/watch?v=videoseries I shot whilst formation flying in among Cumulus and keeping away from the CB. Never the less we caught a gust front on the way home. In observing the effect on the camera, remember it was a gyro stabilised camera!

 

If you aren't sure, seek the advice of your instructor. The CAT can get you!

 

P.S. Legal distances from cloud were observed, as were hemispherical levels.

 

 

[Yenn]

Low wing loading accentuates the bumps, so it doesn't hurt to have a bit of weight on board, full tanks maybe.

 

 

[shags_j]

Jesus Kev, Man up!

 

Just kidding, we've all had that sinking feeling where you are wondering if those little bolts will hold the magical planks keeping us aloft.

 

Only thing I can suggest, as above, early morning is the best (i find even late afternoon can be a pain sometimes). Also take note of the terrain you are flying over, avoid the thermals etc. Slow down also and the flight should be a bit smoother.