When I started this game, I quickly discovered a lack of easily accessible information providing some much needed information (even if I didn't realize that I needed it). While I do not claim to be an expert, I have learned a lot so far and I'm also a registered flight student :). As I grow in fight school, i'll add my knowledge here to help everyone. So, here goes and remember that this is primarily for the new builders.
Basic building for stability and some newbie tips
Place your primary wings along the center of your COM (Center of Mass). This is as true in Simple Planes as it is in the real world.
When you’re a beginner and until you get the hang of adjusting your plane to achieve very specific and intended results, place the nose in direct line of your COT (Center of Thrust). This truly aided me when I was scratching my head early on. This does not mean your plane must be perfectly straight and level each and every time; however, while you can certainly play with rise and run options, always return your nose to level with the COT. Again, as you learn and grow with experience this rule will change; however, early on it can be a life saver.
Adjust the Dihedral. Giving the primary wings a slight elevation (true dihedral), can and will increase stability. Be careful not to go too extreme or you will experience the opposite effect.
Take the time to learn about wing types. Researching real world aircraft and various wing structures helped me out greatly when I started. Fir example, what does a Delta Wing setup do for an aircraft vs. a Straight wing or maybe even a forward swept wing? Great questions to ask and learn.
Vertical and Horizontal stabilizers are just as important as the primary wings. Make them too long and you’ll have issues; same with too short. There is not a perfect fits all answer for size as it largely depends on the over-all structure and thrust capabilities of your aircraft. This is a good place to experiment if your plane doesn’t fly the way you want it to. Make small adjustments and fly the plane. Repeat.
Test test test. When “fixing” stability issues, don’t adjust too much too quickly. There’s no need to rush. If your new, and that is who this forum post is for, then you may be looking for the answer to flight issues over all of the control surfaces of the plane. Make small adjustments to one thing at a time. For example, if your plane is constantly lifting on it’s own, rotate the primary wing along the x-axis, but do so in small increments and test fly the plane. No matter what you do, remember what effect it had on the aircraft even if it did not achieve the desired result, it might on another build altogether.
Achieving Fuel efficiency. This can be a frustrating part of building in Simple Planes. You finally build your dream fighter jet only to fly it for 2 minutes (if you’re lucky) before you run out of fuel. Maybe you only just have enough time to attack the USS Beast before you run out and can’t make it back to the airport. You may be tempted at this point to turn to a mod even, and if so, more power to you. Just remember that at this point, not everyone will have access to the most amazing dream fighter jet that you have just built. Fear not, there are options. Simply adding fuel to every conceivable surface is not always the best option. More fuel mean more weight (at least at first) and this can translate to little effect if any. First, try adding fuel to the stabilizers. Sometimes this alone may give you enough extra fuel, without too much extra weight to achieve what you’re looking for. Maybe you are specifically building a short range fighter? Remember that you can add fuel to the fuselage blocks, and much more of it. If you add to the block closest to the COM and COL, you’ll most often notice that there’s not much effect on overall performance. Adding fuel to blocks more forward or aft of these locations will cause the COM to “shift” absolutely changing the flight characteristics. Lastly, check the overall weight of your aircraft. Don’t get into the rut of adding all the dead weight (1000 lbs.) or nothing. I do often download aircraft only to discover that they either have a full amount of dead weight on a part or none at all. Use the adjustments in between max and none to achieve the best performance overall and even reduce the overall weight of the plane. More weight equals less fuel efficiency.
Lastly, be aware of where your COM, COL, and COT are located. I’ve watched a number of videos online (YouTube) where someone builds a plane only to have it continuously fail over and over again; never once seeing them open and view the COM, COL, and COT. Without these in the correct alignments, you’ll never have a stable, let alone, flying airplane. Basic rule of thumb is this: The COM should be in front of the COL. The further away from the COL the COM is, the less maneuverability you’re likely to have; however, this can and absolutely does change with specific types of models. Don’t assume that just because your COM is in front of the COL that you’re good to go automatically either. Spacing matters and it’s a perfect place to start when adjusting a model; however, don’t forget the other basics as well. If you have to move your COM, pay attention to your wing location as a result. Remember that, especially when new to building, you should always try to keep your COM near center of the OVERALL shape/area of the primary wings. Even if your wing starts behind the COM, make sure that over the course of it’s length, that it goes through and even passes the COM line. Trust me, it will absolutely help you early on.
Some issues and corrections I’ve faced and learned.
Airplane has a tendency to lift on its own when attempting level flight.
At first, you may be tempted to continually add extra weight to the rear of the plane, move the wings backwards or forwards, replace and adjust the shape of the horizontal stabilizers and vertical stabilizer(s), etc.. And, yes some of this may be required for a truly successful build; however, there are a couple of additional tricks that can be used. 1. Adjust the airfoil on the horizontal stabilizers. Contrary to popular belief and videos on YouTube, you can adjust these with success. Simply try moving them to semi-symmetric or even flat-bottom. 2. Rotate the primary wings along the x-axis. I honestly didn’t even consider this at first and feel silly for it now; however, you have to learn somewhere. BE CAREFUL when you decide to rotate your primary wings as this should be done in small increments. Literally begin with a move from 0.0000 to 1.0000 and so on. Building a successful model requires a lot of takeoffs, landings, and maneuvers over and over again for testing. 3. Use your dihedral option. While the more experienced among the Simple Planes community may be saying “duh” right now; many beginners won’t understand the flight changes that occur when using this adjustment. It’s much more than just looks. 4. Don’t be afraid of using your trim options. Unless you consistently have to adjust your trim to extreme lengths, trim is a very real part of real world flying. Experiment.
Airplane has a tendency to “fall” or “dive” when attempting level flight.
Adding too much weight in the form of dead weight can certainly cause this issue; however, you might be scratching your head when you remove even a small portion of this weight only to have your plane lift itself completely out of control. Using the above methods for a “lifting plane” in reverse will rectify many of these issues.
That shaky shaky yaw problem
This issue plagues a great number of Simple Plane engineers and pilots, so don’t feel alone on this one. You may notice that even the “stock planes” that come with the program have “shaky yaw”, especially with faster, fighter aircraft. There is a reason for this in the real world that I’ve discovered applies to Simple Planes. Have you ever flown the F/A18 Hornet? Neither have I, but I have done so in FSX and also have taken the time to research the plane as it’s one of my personal favorites. Guess what? It has what you might call a “shaky yaw”. Yaw is NOT the primary source of turning a plane, and even in the real world, use of too much yaw will not only shake a plane, but overstress the stabilizer resulting in catastrophic failure. Yaw does have a purpose however. Yaw is used for “fine tune adjustments” of flight heading and level correcting when turning. Cessna pilots will turn their aircraft using a combination of the ailerons and the rudder. Also, the faster you go, the worse the problem is likely to be. If you still have serious shake even with slower speed prop planes, then there are a few things to check. 1. Check the overall balance of the plane. Believe it or not, sometimes adding weight opposite the yaw control surface is enough to “stabilize” the yaw system. 2. What shape are you using? Adjust the shape of the yaw, possibly even more so that the control surface option provided with the wing options. I’ve discovered that I required a swept rear stabilizer for stability in flight, let’s say. What does that do to the yaw? It gives it an extreme angle which will cause more “rolling” than anything else. It does help when the control surface is more perpendicular to the COM and COL. Don’t misunderstand, some angle is perfectly fine. If you’re new to the game (again who this is really for), then consider removing the yaw control surface altogether. Before anyone gets angry at that… Get good at all of the other stability requirements and the effects of changing things on them. This will allow you to “see” the issue with your yaw stability much easier.
Airplane is rolling on it’s own and/or turning on the runway on it’s own
9 times out of 10 this issue is caused by a balance issue. When using the mirror function of Simple Planes, it is very important to know that it isn’t always fail safe. The mirror effect is based off of the cockpit location plain and simple (no pun intended). Get used to using the X, Y, Z menu and adjustments when both building and checking the planes functionality. Click a mirrored part on both the left and then the right and ensure that the X, Y, and Z locations (numbers) match. If not, there’s your problem.
I’m perfectly certain that I will think of other things to add to this list of issues and tips for beginners, and can even almost guarantee that the very moment I post this, a hundred things will come to mind. Luckily that’s what updates are for. ?
Enjoy playing and I can’t wait to see your awesome builds!
@MongooseZiya increasing the distance between your lift and mass does help with stability but greatly decrease your maneuverability, I solve this by adding vtol engines/thrusters they help maneuver but gets funyk at times. There's no real way to make a stable aircraft In simple planes unless with help of flybywires, same to what we do in real life, we use flybywires to attain stability without sacrificing maneuverability.
look online, there are flybywires sort of available for simple planes, or learn how to set it up yourself. One example of this is the f-18 default to the game it has flybywires you can see it auto corrects itself(terribly)
i'm trying to make a delta wing craft but when my CoL, CoT, and CoM are all centered the plane still is unstable because it is delta winged. can someone help?
@jamesPLANESii I apologize if I misstated my stance on the Yaw. I've come to see through comments on various builds that a lot of people think that shaky is wrong. I attempted to use the F/A 18 Hornet as an example of real world shaky yaw and why it shakes. I think from what I've seen and read a few different places, that there is often a misconception regarding yaw and its proper use; some believing it to be a primary method of turning an aircraft. Of course, we know that isn't true. However, reducing shake is a real thing both on SP and real world. Again, I do apologize if I misstated my position in the above post. Actually, some degree of "shake" (yaw oscillation) is to be expected given the forces at work along the empannage of an aircraft. :)
Lol sorry y'all I'm a writer!
@randomusername and maybe on the models you are building, using the Dihedral is something unnecessary for stability. However, he is correct on his points regarding dihedral. This is why I stated in the post that adding a slight elevation to the wings can add stability. It's about what is known as positive, neutral, and negative stability. In flight schools, they will use planes with a slight dihedral because if the student somehow loses his or her yoke control for a moment (maybe had to sneeze or something I don't know) the oscillations that would follow would eventually settle in a return to stable flight; positive stability. For comparison, neutral stability is when the oscillations would remain the same until the pilot gained control, and negative is when they worsen. While certainly not alone in affecting these types of stability in a final aircraft; dihedral is an important detail to consider. Now in a game such as simple planes, James is correct in how real world physics and SP physics are not alike; however, to a new player who may have zero idea on how to build a first, second, or third model; learning use of dihedral and its effects is a huge aid. :)
Wow I wrote a lot there lol
I disagree with “don’t touch the dihedral”. Planes have dihedral because it helps with level flight. For example, if the plane isn’t quite flying level (when I say level I mean level in the roll axis), the plane slips slightly into the direction that the plane is banked, and the upward dihedral helps with leveling the plane off (because if you imaging the plane flying directly sideways with upward dihedral, it’s gonna roll, if ya know what I mean). If your plane doesn’t have enough dihedral, or it has downward dihedral, the plane is gonna do what my Scout Dragonfly does quite a lot and start rolling off to the side when it isn’t perfectly level.
Some planes have more dihedral than others because of how the wings are positioned. If you look at how the dihedral on low-winged aircraft, such as the Piper Cherokee, you will notice that it’s wings have quite a lot of dihedral. This is because the CoM being above the wings, the plane is gonna tip. With high winged planes such as the Cessna 172, you will notice that the wings have very little dihedral. This is because the CoM is below the wings and that helps with stability. With some planes, such as the Antonov AN-225, the CoM is so far below the wings that the plane has too much roll stability and actually needs a dihedral down to have easier roll.
The pendulum thing with the wing location I’ve found doesn’t really work on SimplePlanes because the wing physics when planes are slipping/sliding aren’t very realistic in the game, so I tend to give planes some extra dihedral, but not much.
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@randomusername
With the shakes yaw, there are a few users that strive to stop the yaw from shaking, but fixing the shake is actually unrealistic. In gliders, if you use full yaw, and go back to the centre, it shakes like crazy because of the inertia of the long wings. Especially the 1960s ones like the KA-6. Sometimes I try not to move my feet so fast because I find it a bit unsettling lol.
Personally, I actually sometimes use the shaky yaw to my advantage when I’m flying on SP like when I’m trying to test the spin physics of my plane. I yaw one way, then yaw in the opposite direction, and manage to stall the tail because of the yaw inertia.
@Davjlee yeah that's what I was thinking of doing also, I kind of want to get a kit plane but my parents don't believe in engineering! lol. and to be honest when I got on my first airplane (commercial) I was so scarred, I had a fear of flying! but then I learned how plane crashed happen with airlines, they really don't...
@randomusername lol that's exactly my point in writing a basic tutorial. Most people new to this game will probably not understand usefulness of counterweight etc.. I mentioned that the "rules" listed are bendable and even breakable as one learns and grows in their understanding of Simple Planes physics. You definitely have some awesome builds and hopefully anyone who advances in model development will be able to, not only research more advanced models, but also have the knowledge to understand what they are seeing. :) Thanks and I look forward to seeing more of your builds.
@ACEPILOT109 I hear you about the larger aircraff lol. It's good that they are much safer than ever before; however, there's a lot to be said for "flying" an aircraft manually. I think that there is certainly a lot to learn and it's good to learn IFR as well as VFR. If I go the commercial route, believe I'll be flying an ultralight two seater on my days off! :)
@Davjlee wow! that's cool! I feel the same way as you, want to be a pilot, and not sure what to do yet. in a few years ima see if I can get into APT also. for now I'm really into RC Aircraft and light aircraft. I'm not sure if I want commercial simply because big jets are not really "flying" there just auto pilot flying things, not sure if that makes sense. I'm also into aerospace like you, I mean, its simple planes of course I do! also, are you in Civil Air Patrol? I'm trying to get into that but Boy Scouts is always in the way. I'm not an expert in flying (yet) so I'm not sure what I want to do. if I get a plane I want to get a 150aviation is the best!, I love the way they look but I have never flown one (yet).
@ACEPILOT109 Thanks. I have only recently begun, however, I was lucky enough to do a discovery flight in a Cessna 172 which was certainly an upgrade to the 150 which is what most do. I have always had an absolute love of all things aerospace and specifically "fighter jets". I also recently took the entrant tests for APT; discovering as much as I can about the school and seeing if a shift in schools is a good thing or not. I know without a doubt that I want to become a fully licensed pilot; however, I am as of yet unsure of which avenue to pursue in aviation (commercial pilot, charter pilot, cargo, etc..). I truly appreciate your feedback and am absolutely always open to suggestions, pointers, critique, etc.. Also, in addition to the Cessna, I am hoping to fly some of the low wing aircraft as soon as I can. I think that waiting for my first solo is already the longest wait :D.
@CrashFighter05 lol. Right :). There is a lot to say and I was actually trying to keep it pretty basic and simple.
so I thought because your not high in the points this would be one of those post. you know what I mean. being here for almost a year and 1/2 and being an intermediate RC pilot with some real flight experience in light aircraft I would say this is really good.
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so your a flight student? what you training on?
Nice book!
Very helpful to new players.