ScienceisCool

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I had the day off yesterday so I went to the field for some flying. I got there around noon and it was already almost 100 degrees out so I flew once and packed it in. I was wondering if any of the more seasoned flyers could share some things to look for or things that can happen when flying in hot temps to our planes and equipment.

Thanks!
John

GaryHarris

The heat index at Scobee was 117* on Sunday at about 7:30 am. I'm outa there by 9:30 am. LOL

bkdavy

My Feedback: (1)

The planes really don't care about the temps, but make sure you have some shade. Clear canopies can raise the temps inside the plane, and you don't want to overheat recievers and batteries. You may notice some wrinkling of the covering if its cheaper covering or not properly adhered. The engine will probably have to run a little leaner, as the air isn't as dense, and you're going to have less power. If you have an asphalt pit area, keep the planes off the asphalt until you're ready to take off and fly. Keep your fuel in a shady spot, and keep the bottle capped to minimize evaporation.

Most importantly, take plenty of water with you, and drink it constantly (I take 1/2 gallon jug with me). Its very easy to get distracted and then get dehydrated. Stay away from caffienated beverages.

Brad

Minnreefer

My mother-in-law wants us to move down to Conroe (distant burb of Houston) and I said no way, I can't stand the heat, I don't like anything over 85. I would think to try to fly a little earlier in the day would help and or try to bring some shape for you and the planes.

Would it help if I told you it was 56 here this morning?

Jon

brett65

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Lets talk about morning temperatures in about 6 months buddy.

blueapplepaste

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Yeah, we can't fly IC at our field before 9 am, so during the summer I pretty much get there a 8:45, and as soon as it hits 9 I'm flying, get a couple of flights and go home. It was in the 100s all last week and was miserable, even at 9. By ten I'm packed up and heading home.

I always make sure to wear a hat to shade my eyes and head and also bring a big jug of water with me. Even just standing for an hour, its easy to sweat off a lot of water, so make sure after each flight you have some water. Also keep your fuel out of the sun if possible, as well as your plane. As covering will start to wrinkle if it gets hot enough.

DGUY

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Brett65,
I hear ya what would the morning temps be up there say mid Febuary what think maybe 0 or 1-2 above. No thanks I will deal with the GA heat. It was 130 here in Iraq today.
I tell you I have seen hot. While I was in Kandahar Afghanistan in 2006 it hit 160 for 5 straight days now that was hot for even them. You could drink a case of water a day no problem and never have to take a wiz.
Derrick

bonebreak

I went out last Friday, and it was 101. I stayed for about 3 hrs. I just make sure to bring plenty of water, and make sure to get the table with shade. I have worked outside in the summer for 9 years, so it doesn't bother me too much. I plan on going tomorrow, and luckily, its only supposed to be 95. I will probably end up staying for 4 hours or so.

gboulton

My Feedback: (15)

Clearly, the primary consideration is one of personal safety. Obviously, staying hydrated in temps like those is the biggest challenge, and the most important thing. You should also consider your tollerance for sunlight, and think about such things as ways to find shade, sunscreen, etc.

You could also, budget/space/transport depending, consider "Easy-up" style portable awnings, or generators to power fans/coolers. Several guys I know also pack lunches and use the "lunch break" time to get out of the hottest part of the day.

Beyond personal safety :

They absolutely DO care about the temps.

Temperature is one of several factors that impacts density altitude. Obviously, you can google a zillion tutorials/charts/explanations of density altitude, but to grossly oversimplify the thing:

It's the altitude your airplane thinks it's at. (Don't shoot me, purists...I KNOW that's a gross oversimplification...it's sufficient for our discussion here)

At higher density altitudes, your airplane will, quite literally, find less air. This has two effects on the aircraft:

1) Lift is reduced for any given angle of attack. As a result, AoA will need to be slightly higher than "normal" for any given "thing" the airplane is doing...thus increasing drag. Airplanes will glide shorter distances, come out of the sky a bit quicker, that sort of thing.

2) Engines become richer just as surely as if you'd opened a needle. Less air is less air, whether you've reduced the air density or twisted a needle doesn't matter. Thus, your engine will produce less power at any given throttle setting.

It's also worth noting here that high humidity ALSO raises density altitude. While the OP asked about temperature specifically, we all know it's not unusual...especially in the south...to find high humidity in the summer months.

What's important to note here is that you've created a pretty significant "combination" here. You have an airplane generating less lift AND with less power available. That can absolutely cause an airplane to behave in unexpected ways.

It's not that there's some magic temp at which suddenly the airplane will become unflyable or anything...but these things DO matter in certain situations, such as deadsticks, high demands on the engine, etc.

hudmun

[sm=71_71.gif]I noticed a couple weeks ago the display screen on my transmitter went black from the sun shinning on it , stuck it in the shade and it came back.

brett65

My Feedback: (18)

My cousin's husband got back from Iraq late last year and told me all about it. He was an Army field medic. Couldn't be more proud of our guys doing what they do in such crappy conditions.

jamesc43

My Feedback: (2)

I agree with gboulton. Air temperature has a big effect on air density. I live in CO (6200ft). The airlines have to restrict the amount of weight they can place on a fullscale airplane during the hoptest parts of the summer months because the air density is so thin.

gboulton

My Feedback: (15)

Admittedly, we're probably not in a situation (though maybe at 6k+ you are *heh*) where we need to make any real "changes" to our airplane just because it's hot. Perhaps we'll get a bit of burble from the richness maybe, or whatever..but in general, we're not likely to be going "Hrmm...better only fill halfway up to cut down on weight!" or anything.

Where it CAN bite us, however, is in certain "critical" situations...where we expect the airplane to do one thing, and even a second or foot of difference from that can spell disaster.

As an example...I mentioned deadsticks above...

We're nominally at 632' MSL here, but I've seen plenty of days when I check AWOS and find a density altitude of 2500' or more.

A change like that can easily take a situation that was borderline "Should I make the turn and try for an upwind landing, or go ahead and come in downwind" and turn it into "try to make the turn and you've lost an airplane".

Anywho,...like I say...I don't mean to suggest that we should all be running around calling our nearest airport's AWOS hourly, and adjusting how we fly or which airplanes we take because of it.

I think, however, in any discussion about "the effects of heat", it's probably appropriate to at least be AWARE of the impact it can have on our airplanes, and give some passing thought to how we might use the awareness in certain situations.

gboulton

My Feedback: (15)

*heh*

Just for grins and giggles, I just checked MQY's AWOS.

Density Altitude is currently 3200' here....and it's not really that uncomfortable outside.

Gray Beard

My Feedback: (-1)

Yesterday it was 86 at 5:30 when I got to the lake bed to fly. It was slated to hit 112 by early evening, I didn't look but I don't think it made it that high. Keep in mind there is no real humidity here to speak of so it never feels as hot as it can get. We park our vans due east and just open up the lids and set up our chairs in the shade, move as the sun moves. Some of the guys have shade tents they hook up to the back of there trucks or vans. My van always has a 6 pack of water in it. I keep a case of water in the freezer and put three frozen bottles in my open top cooler so it melts, never melts all the way so I just keep adding water as I go.
As for the planes, the heat doesn't bother them at all until the weather starts cooling down come late fall. When you tune them for 100 degrees and it drops into the 60s things start changing so we have to fatten up the high ends until it gets into the 30s and 40s, comes to about 4 clicks.
Today a storm is blowing through and it's warm and overcast. Humidity is up to 17% and for us that a case of the mug. I like the heat but can't stand the humidity so this is a great place for me.

ChuckW

Hit 106 here yesterday and the house AC stopped working. Not good. It was hotter than he** up on the roof but I got it working again.

I also just get to the field early and leave earlier than normal on really scorching days.

draftman1

It was a scorcher yesterday wasn it Chuck! leaving the house was like walking into a blast furnace

ChuckW

No kidding. I've been in NJ and PA for the past 1-1/2 weeks where it was either raining or overcast and in the 70's. Getting off of the plane in Fresno was like walking into an oven.

KW_Counter

I used to live in the Imperial Valley, south of Palm Springs.
It wasn't considered hot until we got to 118F.
125F was not uncommon, usually close the airport then.
And no, this isn't dry heat. Its close to the Gulf of California and
with the agriculture its humid.
We started flying at 7:00 am and were gone by 11:00.
Winters were awesome!
Have Fun.
KW_Counter

Villa

Hi ScienceisCool
I designed and built a 46 size Pusher/Puller twin engine SPAD plane. It had two 28 Magnum engines. Occasionally I would take off on one engine. The plane frequently had to be literally "jacked" off the ground with violent use of the elevator in a jerking manner. It could easily take most of the runway. Some times I would finally be in the air, just a few inches off the ground, but could not make the left turn without the wingtip touching the ground. Of course, it being a SPAD, a crash was no problem. Usually zero damage. On very hot days (near 100F) nothing I could do would get the plane off the ground on one engine. In the winter there was never a problem. The colder the better.

Lnewqban

I would like to add that hot air is also more viscous; hence the drag by friction of the model is higher.
That is for the model.

For the pilot:
In hot and humid days down here in Florida, drinking plenty of liquid is not enough.
This is because the high humidity does not allow the sweat evaporation cool down the skin and the body enough.
Cooling down by splashing fresh water over the skin, using fans, and even stepping into the air conditioned car for 10 minutes may prevent passing out due to hyperthermia.

gboulton

My Feedback: (15)

Err...pretty sure that hot air is LESS dense than cold air. Heat excites molecules/atoms, which vibrate more...and thus take up more space. Therefore, for any given parcel of air, the warmer it is, the fewer air molecules it can hold.

On the flip side, warmer air IS capable of holding a larger amount of water, but then again, there's no implication that just because air is hot that it is holding more water.

Gray Beard

My Feedback: (-1)

I spent a 4th or July weekend out at the sand dunes of Glamis one year. I had a Sand dragster finished and just had to get it out so I could break it and make changes before I could take it apart and paint it. As hot as it is I had a ball, about 12 of us out there, we spent the day swimming in the canal and ran the dunes at night.
Those were the days before I developed gray mater!!

gboulton

My Feedback: (15)

The beard, the hair, or the brain?

Minnreefer

All three for me, and I am only 37, but I am blaming the wife and 2 kids

P.S
How do dyou find the density altitude, or do you have to figure it out with a formula?

Thanks