All posts tagged 'Summer'

Why Aircraft Engines Thrive in Colder Temperatures

Since day one of flight training, we have all heard pilots say that aircraft perform better when it's colder outside. 

You may have heard the term density that has to do with this factor but may have not have seen it actually broken down and explained before. So here's why:

Temperature and Density

When air is entering an aircraft engine to be mixed with fuel, it goes through the 4 phase process of "intake, compress, combust and exhaust" in order to generate power. This is the same for both jet and piston engines. 

But how much air can actually enter the air inlet in order to enter the 4 step process?

Well, the slightly better question is how many air molecules

jet engine design

As explained by BoldMethod.com, "cold air molecules move slower and collide with less energy than hot molecules, causing cold air to become denser. As temperature drops, more air molecules enter an engine, and as temperature rises, fewer air molecules enter an engine."

The more air molecules that can enter an engine, the more power/performance that can be generated, therefore cooler temperatures are more preferred. 

Density Altitude & Performance 

Since we're discussing the density of air in relation to temperature, density altitude goes hand in hand with the topic. Density altitude is altitude relative to standard atmospheric conditions at which the air density would be equal to the indicated air density at the place of observation.

Or for better terms, simply put it is the density of the air given as a height above mean sea level (MSL). 

The higher you are above sea level, the less dense the air becomes, posing the same problem: fewer air molecules entering the engine, therefore, less fuel is mixed with it and lesser power is generated. 

So if you're flying somewhere with a high field elevation such as Jackson Hole, Wyoming for example, and you're taking off in the afternoon where temperatures are at their hottest, you may want to double-check performance numbers. High altitude and high temperature is the worst combination for your aircraft. 

This can even potentially stop you from being able to take off, where your only option is to wait out the temperature until the sun goes down and air cools off again. 

So, if you've been flying and curious why your plane seems more sluggish than a few months ago, now you know! Airplanes like the cold!

questions or comments? Write us below. 

Know Your Airspeeds and How They Can Help You

No matter how much you flight plan and prepare for a flight, sometimes unexpected things happen that can throw you for a loop. The best way to be ready for these situations is...

1) Always expect the unexpected

2) Practice how you'll handle situations that can arise

3) Stay up-to-date on your knowledge

One valuable way to do this knowing your airspeed indicator.

I bring up being prepared because it's summer, meaning the air is hot, it's bumpy, it randomly builds into convective layers, and is sometimes simply unpredictable. So being able to manage your airspeed and knowing when to be in which arc is a good way to keep you and your passengers safe. 

Airspeed Indicator

The first two on the bottom of the indicator are Vso and Vs1: your stall speeds with and without flaps. Always be checking yourself on takeoff and landing to make sure you're not too close to these. In fact, if you're landing in gusty winds/tailwind carry a little extra power to give yourself some extra speed. 

Vfe is your maximum flap speed, so if airspeed is being erratic on a bumpy day and you're trying to bring flaps down for any reason, give yourself some cushion room as to not overspeed them.

The green arc is your normal operating range for the aircraft. Something that is not marked on the indicator however is Va, your safe maneuvering speed. If you're going to be making full abrupt control movements (or penetrating turbulent air since it does this to your controls) then stay not only below green arc but also below Va. 

Vno is the top of your green arc with the yellow arc to follow. The yellow arc is simply your caution range, it's not a specific V speed but it's warning you that if you keep going fast you'll reach Vne, your never exceed speed. Regardless of if you're in smooth or turbulent air here, you could damage the aircraft. This would most likely happen if you had a lot of power in with the nose pitched down. Imagine flying near a thunderstorm cell and catching part of an updraft. If you're lucky enough to recover from it, you might look up to find yourself in this situation. So scan everything, keep the aircraft under control and stay calm if this does happen to you. 

Phenomenon such as updrafts and windshear can be encountered outside of a thunderstorm area. The best way to predict which areas they may be in is PIREPs. So do thorough flight planning! 

If you're currently flight training and college and need some help financially, head on over to our scholarship page and apply! 

Questions or comments? Write below!

Basic Math Behind Radar Tilt

There's no doubt about it: as we get into summertime, we're transitioning into the fun game of dodging storm cells. 

The air is hotter and more unstable and quickly builds into convective-type clouds that keep rising into the troposphere, next thing you know you have pop-up thunderstorms everywhere. The job gets especially fun as they grow into squall line thunderstorms. The best way to stay safe in these situations is to plan ahead, always have a backup plan, let ATC know what you need, then cooperate with them, and know how to use your radar.

Clouds in the Sky

Each radar is slightly different from the other but for the most part, they work very similarly. The first step to knowing how to tilt your radar is knowing how long your antenna is. The length corresponds to the beam it puts out. For example, a 10-inch antenna puts out a 10-inch beam, 12 inches has 7.9 degrees, 18 inches has 5.6 degrees and lastly, 24 inches has 4.2. So as the length increases, the beam degrees decrease.

If you happen to know the width of your beam in degrees then you can figure out your tilt with a little math. This photo and mathematical formula from Code 7700 explains it simply using the G450 as an example, where they have the 24 inch 4.2 degree beam:

Beam Width Gulfstream G450

So at 45,000 ft, it would take 100nm to paint the edge of the ground clutter, and tilting the beam to 2.1 degrees would point it at level flight. 

While it can sound a little confusing at first, using this formula and adjusting the tilt at the same time will help you adjust to being able to tell when you have the radar set how you want and when it needs to be readjusted. A good practice is to always use your radar while you're trying to learn it, even to see terrain rather than the weather. Most would recommend whether you're in the Texas flatlands or near high terrain in California that it's good to have your terrain feature on. 

Weather Radar on Map

Something else I like to do to double-check I have the tilt on an accurate setting is to see if I have service/wifi onboard like this G450, open up that Foreflight radar (or your most trusted radar app, also highly recommend MyRadar). After all, two is better than one!

The last tip, but most definitely not least to trust your onboard radar, is if you're VMC, simply look outside. Night or daytime, you can see lightning and guestimate where that cell is in relation to you. If you're not sure how close it is, take a 10-degree deviation off course to feel safe. ATC 99.999999% always approves deviations for the weather. They want you to land safely just as much as you do. 

Hope everyone is ready for the summer flying season to take place! Remember to be knowledgeable, be safe, and download the BuyPlane app. Safe flying everyone. 

Effects of Summer Flying and How to Overcome It

First and foremost, let's state the most obvious effect of summer flying: it. is. hot.

Being a pilot from Texas, I can personally say you should check on your southern friends. There's a good chance we're dehydrated and .2 seconds away from passing out due to heat exhaustion. 

Okay, maybe a little overdramatic....but it is hot. 

When flying in the summer, whether as a student, flight instructor, or any type of general aviation pilot we need to understand the effects of the weather changes. 

Rule number 1: Always carry water. Even if you just hydrated before your flight and don't think you need it, grab water anyways (and by the way, try to go green and make it a reusable water bottle while you're at it). From first-hand experience, dehydration and heat exhaustion can have a bigger impact on flying than you'd think. Your decision-making skills and effectiveness on hand-flying the plane start to deteriorate. If ignored, dizziness and a headache can start to occur. This becomes even more important on long haul flights. Don't be the newest accident statistic due to poor flight preparation.  Even if you're in a rush, take 2 extra minutes and grab that water. 

Rule number 2: Take into account the changes it can have on aircraft performance. If you're taking off from an airport with a short runway, even if a ground roll is normally adequate, double check it. The hotter it is, the longer ground roll you need. That point you're used to rotating at or obstacle you're used to clearing might not be your friend today, especially as the heat rises continuing into August. A great tool to help gauge the temperatures at the surface and at altitude is the GlobalAir Aviation Weather Temperatures Tool. Just click the "national weather" tab, then click "temperature" and see it all illustrated on an analysis chart. A quick tip: if you're using it to plan a flight for later in the future (and not 30 minutes from now) make sure you click for the right time frame! left

Rule number 3: Still on the weather subject, check your winds before heading out. You're most likely to encounter gusts of wind on a hot summer day with calm winds at the surface. I've also experienced this firsthand, so it became a learning experience. As soon as I reached 1500 ft the wind picked up, and it didn't stop. The turbulence actually reached moderate for me that day, so I cut my flight short and went back. No sense in taking chances to keep going and fighting the plane the entire time! For any situation with undesirable weather or even maintenance issues remember this: it's better to be on the ground wishing you were in the air than in the air wishing you were on the ground. The GlobalAir Winds Aloft Tool is also a great resource in planning for this. Be sure to check this and local METAR/TAF for each upcoming flight to ensure you don't get in a situation making you wish you were on the ground.