By now we’ve made speak of more than a few human and environmental conditions in this column. Boredom and fatigue are two challenges we’ve tinkered with most recently, but with summer in full swing now seems the time to light a fire under the most common environmental issue facing most of us: heat.
Like cold, heat has its nuances. My Florida friends are acclimated to the sticky humidity of the Gulf Coast, which isn’t to ignore everyone else gathered around the shores of the Gulf of Mexico—or America—depending on how politics plays on sectionals. Or the buggy oppressiveness of the Carolinas. Or the worst I’ve ever seen, which is landing among the corn in Iowa during AirVenture jaunts. It was worse than China.
There’s something to wet heat that’s difficult to define. It’s everywhere, for one thing. Getting in the shade doesn’t help much, nor does drinking water typically offer an immediate reprieve. It’s also unmistakably uncomfortable, what with your clothes clinging and all those cicadas singing.
Out West it’s a little different. “It’s a dry heat,” the locals chant as you consider the first-degree burn left by the chrome seat belt buckle. Yes, it’s dry but it’s also %$! hot, as in unhealthy, or if you’re really having a bad day, fatal. I once had a young automotive colleague all hot to trot—pun intended—to cover a story in the Phoenix area. In July. My wise counsel to avoid the story until fall had the usual effect. “I’m a Florida boy, I’m used to the heat,” he countered. A couple weeks later that colleague flew out to Los Angeles, jumped in a car with another writer, and headed east to Phoenix. My phone rang several hours into their journey and I no sooner said hello than a stream of expletives poured forth, all unprintable and occasionally punctuated with “hot.” I’ll confess to a wry smile and fatherly pride in the rapid and thorough learning on display; the profanity, voluminous as all of Merriam-Webster could provide, was excusable, and not without its humor given the, er, heat of the moment.
The point is, it gets dangerously hot in the southwest in the summer.
In our airplanes heat is an insidious danger. Like carbon monoxide it doesn’t even tiptoe in, it simply arrives and stays past all grace. Energy saps, cognition sags, and endurance wilts along with the rate of climb. Bubble canopies might as well be magnifying glasses, their greenhouse effect making you wish you were a saguaro cactus. Even skylights in high- wing aircraft cry for a sunshade to protect your bald spot, and there’s no such thing as too large a cabin air vent—or exit.
Worst are open cockpits as there’s absolutely nothing between you and mother nature’s broiler. The UV rays laugh at sunscreen as your face tans raccoon-like where the leather helmet and headset don’t reach, and you have no trouble seeing your crow’s feet in the red burn you present to the public the next day.
So, what to do? As an open cockpit guy I treat heat like I do cold: It’s a flight planning consideration. At its worst I won’t fly at all. Yes, I did once race a little sedan in 123° F ambient heat while wearing a two-layer fire suit, but I was younger then. And we spent the hours between practice, qualifying, and racing in a motel pool. I also raced a dirt bike in 118-degree temps in a 50-minute enduro, but I was much younger then. Just as bad was thundering around the much missed Riverside Raceway in 113° F heat in a GT350 Shelby. The heat rejection off the 500-hp V-8 got the cockpit up to 140° F or more; thank goodness I was, you know, younger then and my stint only 45 minutes. But no one has any business flying in such oven-like conditions and I simply won’t go anymore in that sort of heat.
But if it’s hot—but not that hot—then it’s time to do something about the heat. Above all, fly as early in the morning as possible. We all know it’s smoother and less windy in the a.m., but having the discipline to put the beer away early the night before and rise during the witching hours pays handsomely on hot days. Similarly, if you’re getting a late start, then get a truly tardy start in the long days of late spring and early summer. Let the heat begin to fade—if it does where you’re flying—in the evening and ride the last bus before sundown. This is especially helpful if it also means putting the sun at your back.
Then there is altitude. Again, in the West we’re often forced to several thousand feet just to clear the larger rock piles, while our compatriots in the Midwest and East think 3000 feet is for NASA. Summer heat often extends to over a mile vertically, so cruising at 6500 to 7500 feet or above may be required to make a meaningful difference. This is angel territory to many, but it’s really not that high in an airplane with a modicum of performance. Again, Westerners think in terms of 10,000 feet due to the hills, but it is something to think about if you’re considering a new build. The ability to outclimb a sloth pays dividends in more than just terrain clearance. If it gets you into 70-degree temps when it’s 105° F at the surface then the climb is more than worth it.
Even modest climbers can get to meaningful altitudes as long as the oil and cylinder head temps don’t redline in the process. Again, this is another reason to fit a large enough oil cooler with real airflow—or a water spray bar system, which works like a charm. Cylinder head temps rely on well-sealed baffles and properly sized inlets and exits to do the job. Even so, it’s often necessary to lower the nose and accept a higher speed cruise climb rather than asking your sky chariot to climb straight up a rope in the summer heat. It’s all too easy to overheat the engine in the first few thousand feet of climb and it takes forever to cool it off, so establishing a gentlemanly ascent immediately off the runway is good policy, even for those packing big power in light airframes.
Something else the heat may reveal are mysteries of airflow around the cooling or oil cooler inlets. Often a slight change in attitude can trip airflow into a roiling mess around the cowling, with attendant loss of cooling. Lowering the nose, or fitting a minor lip to scoops, can often reduce this phenomenon to more useful levels. Experimenting with climb angles and power settings on normal days can suggest what might be prudent on hotter days.
Then there is you. Yes, drink plenty of water, and don’t worry so much about your bladder. On hot days you really do need an amazing amount of fluid and will lose it simply breathing and sweating. And avoid alcohol, which doesn’t do your heat tolerance any good.
If you’re under 50 years of age heat is likely just a bother, but as you rack up solar laps the ol’ bod narrows its tolerance. A warm-weather veteran, it took until my mid ’60’s before I lightly stepped into heat exhaustion while shoveling gravel one warm day. There was the usual fatigue, then lightheadedness, and then the realization that even though I had stopped shoveling and sat down on the edge of the pickup’s bed I wasn’t cooling off. Recognizing I needed extra effort to lower my temperature I forced the short walk to the shaded, cool concrete floor of the garage and lay down on my back to better connect with the concrete heat sink. Some water and 20 minutes on the slab revived me. It was a good experience as now I can better identify my fading heat tolerance. Combining that with an airplane with enough reserve cooling to perform year-round makes for better flying.
