SimplePlanes is great...I don’t know of a better game where you can design, build and fly an aircraft. It’s as simple as it can be or as complex as you want to make it. The community is great as well, many builders out there creating some spectacular creations, many of them replicas of real-life aircraft. I myself have gone from throwing together a creation and flying around on my phone trying to complete various challenges to trying to recreate real life aircraft as realistically as possible. I am also a real life pilot and have noticed there are not that many real life pilots in the community, mostly it’s simply aircraft fans or those who might aspire to design, build or fly aircraft later on in life. If I had to guess a median age for builders it’s probably in the 15-18 year old range and not many of those people have had the opportunity to fly a plane. As I’ve flown a few aircraft over the past 30 years, I thought that some of you might appreciate some thoughts on common mistakes I see on many replica builds. But I’m going to make a couple of caveats: First, I’m talking about replica aircraft builds that are meant to be as realistic as possible. If you want to make a Minecraft porkchop that flies, go for it...but I won’t be discussing the tastiness of a flying pork chop. Also, I understand that SP, like anything else, has it’s limitations. There is no mod capability on iOS or Android...that’s a huge limitation until SP itself provides a means of accomplishing things I can do on my PC. Hopefully, though, you all might glean some ideas from my thoughts below on how to build more realistic aircraft. Here goes:

1. Trim. I see many replicas which don’t have trim at all, have it connected to flaps or trim that works in reverse. Pretty much all modern aircraft and almost every older aircraft have a trim system, whether it’s manual, hydraulic or electric. It’s simple physics...if you want an plane that can fly slow enough to takeoff and land safely, yet fast enough to outrun those coast to coast trains that AOC promises in the next 10 years, you need to be able to trim for level flight. The alternative is for the pilot to hold control pressures against air loads as the aircraft speeds up or slows down. At first, it would be fatiguing and, as the aircraft accelerates faster and faster, downright dangerous leading to a pitchup, stall and crash or the aircraft nosing over and diving into the ground. Even the F-18, which has automatic trim, HAS TRIM. An SP creation might fly straight and level at 400 mph (I prefer knots, but, oh well), but if you slow down or speed up, you’ll notice the build tends to climb or nose over if you speed up or slow to land. Of course, with onscreen controls, this is mostly controllable, but it is annoying for me as a pilot. And the fix is sooo simple: Use the default trim or simply stack two rotators.
2. Trim connected to flaps: Many jets have systems that adjust the trim as the flaps extend or retract. The T-38 and 737 both do this...heck the 737 has multiple inputs, autopilot, Mach, configuration changes, MCAS, which run that trim wheel back and forth. However, no aircraft I know of has a trim system which requires extending the flaps to run the trim. The fastest flaps limiting speed on the T-38 is 240 knots, on the 737, 250 knots. If I was cruising along at 335 knots indicated and lowered my flaps, I’d damage the jet or just rip the flaps off the wing...not good. So why do so many replica builds not separate flaps and trim? I don’t know of a great reason why they’re set up that way, but many are. Fix: have separate flap and trim controls!
3. Reverse trim controls. You pull back on the stick and the trees get smaller. Push forward and the trees get bigger. Trim controls on most aircraft are set up exactly the same way. So, why the reverse trim? As a pilot it’s, frankly, offputting, and if a build is set up this way, I’ll frequently nose dive into the runway on my first attempt to take off. Here’s the caveat to this one: SOME...some...Soviet era jets were set up this way. Heck, they had attitude indicators which worked in reverse (and Sperry also built one that worked the same way and killed three very famous musicians), so, yeah. But these are very much the exception. Besides, if you took a Soviet era fighter jock and gave him conventional trim controls he’d probably kill himself the first time he tried to take off. So, as a pilot, I say it’s best to set up your trim so that the nose comes up when the trim slider is pulled back (down). If you set it up the opposite way, say, if you’re building a Soviet jet that was set up this way, be sure to mention it in the instructions.
4. Hyper turn rate. Ok, fighters seldom pull more than 9 Gs, for many reasons. And a transport category jet airliner pulls 2.5 Gs. That’s a sustained turn rate of around 15 degrees per second at 500 knots (575 mph, about .8 Mach) down low, or 24 seconds for a 360 degree turn. There are many caveats to this one, too many to discuss here, such as turn rate varies greatly with speed and Mach, but, generally, if you stick with 15 degrees per second at higher speeds, that’s probably as realistic as you’re going to get. But I do see many builds, such as F-5s or Mirages that can whip around and do a full turn in under 4 seconds. Simply not realistic, and though sometimes fun to fly, I notice this immediately. Besides, the pilot would be crushed to death. Another caveat, and this one is a big one; I DO use a faster turn rate up to around 30 degrees per second on some of my more maneuverable builds. Here’s why: It’s just not that fun for me, personally, unless it turns well enough. Also, instantaneous turn rate is always much faster than sustained turn rate. That’s one way to over G your jet, which happens all the time. A pilot can reef back in the stick and the nose will momentarily exceed the sustained turn rate, then the wing will buffet and the nose track will stop. Some modern jets, like the F-16, have computer restrictions to doing this, but aerodynamically, a jet is almost always set up to exceed max G if the pilot really wants to do it. However, there seems to be no way to model this in SP, which is why I use a higher turn rate and just pull back less on the stick if I want to model a more realistic turn rate. But I never, never give my builds a hyper turn rate because it’s not realistic.
5. Hyper acceleration. It’s not THAT hard to figure out what the takeoff roll or even acceleration rate is for a particular jet...the internet is a wonderful thing. Now, this one is tough: the reason is that the SP drag model is a bit off for replica builds. Every single part generates drag, even markings and details that don’t add much, if any, drag in RL. Stock wings generate drag, but so do custom wings using fuselage pieces. Before you know it, your F-100 has 10,000 drag points and goes 300 mph, max, at sea level. Not good. So you find an easily obtainable power multiplied jet engine using the SP search “parts” function and slap that bad boy on there...voila, now your Super Sabre goes 760 mph down low and 1,000 mph at al altitude, great!Except it only takes 3 seconds to get to 500 mph on takeoff. Not realistic. Plus, fuel consumption goes up by the same factor as your power multiplier. Also, not good. This is a common problem and a tough one. You need to be able to mod to delete drag points, but iOS and Android users can’t do this, but there are plenty of modded engines available on the site. That’s why I’m going to post a modded resizable fuselage with “calculateDrag=false”. Post it as a subassembly and build away! Then, add a few stock parts that have drag until you reach a good drag count...I find between 1,000 and 5,000 points for a fighter sized aircraft is pretty good for desired performance and realistic acceleration. Now for some uber advanced techniques...in order to have a realistic deceleration rate, you can add speedbrakes which deploy when the throttle is pulled back and retaining the drag on a wing increases deceleration as you turn, which is actually a realistic characteristic.
6. Unlimited fuel and negative weight. I hate this, I really do. Ever fiber of my pilot brain hates it when I see a build that is -123,000 lbs and it has 2,430,716 gallons of fuel...a gallon of fuel weighs 6.5 lbs! What’s ironic is that SP actually does a great job of averaging weight so, even when building a replica, if I add the right amount of fuel, it’s usually within a few hundred pounds of its real life counterpart. I admit that this surprises me whenever I see it happen. Unlimited fuel...ugh, I can hear it now: “But, ChiChiWerx, my jet won’t fly 18 hrs unless I use unlimited fuel! SP fuel burn is unrealistic! I had to increase engine power or add hidden engines [I couldn’t drag reduce!]!” I once wrote a long forum post covering all this...it was controversial. Suffice to say, SP fuel burn is not that unrealistic, no pilot flies around using full thrust burning gas like crazy, we pull the throttle back in cruise and if you drag reduce (see above), you can get plenty of duration out of normal fuel quantities. I ran a test with my F-100, and I could fly around at cruise speeds for nearly an hour, so SP fuel burn isn’t orders of magnitude too high. The only caveat for this is if you’re building the Hindenburg or the Starship Enterprise or a nuclear aircraft carrier or an electric airplane...you get it.

Concerning all the above, much of this concerns the flight model, which is just as much a part of a build as the form. As BogdanX says, don’t just make a beautiful “statue”, make a build that flies as well as it looks. If you wonder why your 1,000 part build, which looks great, doesn’t get the attention it deserves, it might be because of one of the issues identified above. Or, perhaps it’s simply because you don’t have a good screenshot...fly safe!