Fast > Slow
The history of aviation has been a quest for speed, and many of you will agree that it's just more exciting to go fast. I've noticed a lot of new players on here lately, so I thought it would be a good time to share what I know about making supersonic aircraft. While I only build replicas, don't worry, these ideas will help you build better fictional planes too.
1. Swept Wings
You'll notice most jets have swept-back wings. The shape reduces drag, keeps the center of lift to the rear, and looks cool. But for supersonic planes it serves another purpose: keeping the wings out of the dangerous shockwaves of the sound barrier. When a plane exceeds the speed of sound, powerful cone-shaped shockwaves form around the plane, and the less the plane touches them, the better.
2. All-Moving Tails
Elevators aren't strong enough for supersonic flight, so supersonic jets don't have them. Instead of splitting off part of the horizontal stabilizer to make a control surface, the entire stabilizer rotates to give pitch control. Sometimes they can even rotate separately from each other to help out with roll control. To build this right, you need to stack 3 rotators on each side of the plane, (one for pitch, one for roll, one for trim) and attach the tails to them. Once you've got everything hooked up, test it out to make sure everything moves properly (you may have to reverse the inputs for some of them). Finally, when everything is working properly, carefully nudge all the rotators inside the fuselage and nudge the stabilizers so they're flush with the side of the plane.
3.Trim
Trim settings are important for any plane but for supersonic jets, they're even more important. Trim lets you slightly adjust the control surfaces of your plane to make it fly right under any condition. In real life, all the surfaces (pitch, roll and yaw) have trim inputs, but to keep things simple, I'll only explain pitch trim.
Wings turn speed into lift. The more speed, the more lift. Too much speed and the plane starts forcefully pulling up (and eventually breaks apart), not enough and the plane noses down (and eventually falls out of the sky). Supersonic wings are designed to give just the right amount of lift at any speed. How? With trim controls.
Supersonic wings are symmetrical, and give off very little lift even at high speed. But as soon as the pilot pulls the nose up a bit, it changes the airflow over the wing and causes extra lift. Basically, trim settings let you adjust how much you pull up to match how fast you're flying and how much lift you need.
It's actually a lot more complicated than that, but TLDR trim helps you keep the plane flying evenly at any speed.
4. Landing Gear
No taildragging, jets use tricycle landing gear. Skinny gear up in the nose, big heavy gear under each wing. Read that again: under each wing. Not sprouting out of the butt, not under the tail, beneath the two main wings. The wings hold the plane up when it's flying, the main landing gear holds the plane up on the ground. Just like the wings go slightly behind the center of mass to keep the plane from flipping over in the air, the wheels go right behind the center of mass to keep the plane from flipping over on the ground. There are more reasons for this, and if you want to learn more I can send links if you ask in the comments.
That's all for now. Thanks for reading. Feel free to ask questions.
Now I wanna do all moving wings just to make a point
@asteroidbook345 Thanks!
@asteroidbook345 XD
@asteroidbook345 What plane is #1 ?
@asteroidbook345 Cool and disasterous. They called it the "sound barrier" because it would literally hit planes like a wall, often tearing them apart.
@asteroidbook345 Nice finds, cool looking. None of those are supersonic tho.
@randomusername I think we're going to have to agree to disagree here. I do appreciate you taking the time to explain your ideas to me, and you've been very polite. I just... well, I guess you could say I'm pretty stubborn about this stuff. Anyway, fly safe out there.
@randomusername wrt your comments on trim, all aircraft that vary their airspeed vary trim. Any speed change requires a corresponding trim change to maintain level flight. My jet cruises around at .7-.8 Mach and the autopilot is constantly adjusting trim to maintain level flight. In fact, we have a second trim system, called, literally, “Mach Trim” which adjusts trim during high speed, high altitude flight. So, requiring trim changes above 200 mph is certainly not a cause to call an aircraft “poorly designed”.
@BaconRoll Understandable. Don't be too hard on yourself.
AaaaAh I need to start building again but school and procrastination is getting to me
@F104Deathtrap thanks dark hours have known how
@AtlasSP Add 50 pounds to the wing that rises on its own. If it still turns, increase the weight to 100. If it turns the other way, decrease the weight. Keep doing this untill it flies level.
@F104Deathtrap I think yes, some aircraft have complex wings that it often happens
@AtlasSP Were you using structural wings or rhe regular kind?
There was a problem when I tried to build an ultrasound plane, it always turned to the right or left in the direction of scrolling while flying, for a very long time since SP 1.2 I still had the same problem
@randomusername I think I'm not explaining this properly. Your planes in this game will only fly level at a very specific speed if you don't use trim. If you go faster than that speed the plane will nose up on its own, if you go slower than that speed it will nose down on its own. Trim lets you fly evenly within a wide range of speeds and a wide range of altitudes in this game. It also lets you control how fast you descend, making landing much easier.
@randomusername It applies to all aspects of flight. So not taxiing, but everything else.
What you're describing below is flying at the exact perfect speed for the wings on your plane. Perfect conditions. The speed of the airflow over the wings perfectly counterbalancing the pull of gravity on the mass of the plane causing it to fly perfectly level.
Not only do such circumstances not exist in the real world (thanks to factors like weather etc.) but even if they did, it would be short lived as fuel is consumed and the mass of the plane changes.
But setting all that aside, having a wing with no trim controls means you have to fly at a specific speed without any deviation whatsoever in order to maintain even altitude and that speed varies depending on air density (again, affected by temperature, weather, and altitude).
The whole point of trim controls, control surfaces, flaps, slats, swing wings, boundary control systems, the point of all that stuff is to allow the plane to be as versatile as possible. To fly as efficiently and handle as capably under as many conditions as possible. It might seem like a small inconvenience to be forced to pull the nose up every few seconds, but in real life such issues could have serious consequences including equipment fatigue and more fuel consumption. In the old days before GPS it could even get you lost.
On supersonic jets, the pitch controls are strong. The whole tail moves, and at full deflection it can pull quite a few G's at high speed. Trim allows you to make the subtle changes that permit you to manage your rate of climb or descent. The difference between crashing and landing is how softly you make it happen, a bit of subtlety can really help there.
@randomusername Each wing is designed to provide appropriate amounts of lift within a range of speeds. That range is limited. Supersonic aircraft have to function properly over a huge range of speeds. The most effective way to manage lift is to through angle of attack, and to do that you need trim controls.
Let me put it another way. If the plane constantly wanted to turn left or right, people wouldn't like it. So why would you be ok with a plane rhat always wants to strongly pull up or down?
@Spitfirelad05 It's absolutely based off of it. But if you look up the revised "II" version, it looks much different.
@F104Deathtrap Shenyang J-8II looks like the Mig-21 fishbed
@ChiChiWerx Mostly just a guide for making believable planes, but also helps make SP planes fly a little better. I wanted to get into explaining AoA and flaps, but I already had a wall of text on my hands.
I made many of the same complaints as you recently! Your post is far prettier—nice pics!
Unfortunately there are no Mach effects in SP. A straight winged aircraft and a swept wing aircraft fly exactly the same speed. I tried it awhile ago and was severely disappointed. I do agree with your point, though, realistic builds, even if they’re fictional aircraft, will have swept or relatively short and thin wings if they fly at supersonic speeds in SP (around 770 mph at S.L.).
@JohnnyBoythePilot I'd rather not say. People should be proud of whatever they build.
@Spitfirelad05 Start off with something simple but effective, like the North American F-100 or the Shenyang J-8II (the pointy nose version).