If you're trying to get your roblox jetpack script fuel system working, don't sweat it because it's a classic hurdle for pretty much every developer starting out. I remember the first time I tried making a jetpack; I basically just slapped a BodyVelocity onto a part and called it a day. The problem? Players could just fly forever, which totally breaks the game balance unless you're making some sort of sandbox flight simulator. Adding a fuel mechanic changes the entire vibe of the game. It adds tension, strategy, and that "oh no" moment when the bar hits red while you're halfway over a lava pit.
Building this kind of system isn't just about making a bar go down. It's about connecting the input (the player holding a key) to a set of values that control both movement and the UI. It sounds like a lot of moving parts, but once you break it down into logical steps, it's actually kind of fun to put together.
The basic logic behind the fuel tank
Before you even touch a script, you've got to think about how the math works. A roblox jetpack script fuel system really only needs three main numbers: the Max Fuel, the Current Fuel, and the Consumption Rate.
Think of it like this: every second the player is in the air, you subtract a certain amount from the Current Fuel. If that number hits zero, you cut the power. The trick is making sure the script knows when to drain the fuel. You don't want it draining while the player is just walking around or standing still. It should only trigger when the jetpack is actually active. Usually, this means checking if the player is holding down the Spacebar or whatever keybind you've set up for flight.
Setting up your variables and attributes
I usually like to handle the fuel values using Attributes in Roblox Studio because they're easy to see in the Properties window while you're testing. You could also just use variables inside your script, but Attributes are nice if you want other scripts—like a fuel station or a UI bar—to easily peek at the data without you having to write a bunch of complex functions.
In your main jetpack script, you'll want to define your constants at the top. Use things like MAX_FUEL = 100 and DRAIN_RATE = 0.5. Using all caps for constants is a common habit that helps you remember these values shouldn't really change while the game is running. You then have your currentFuel variable, which starts at the max.
One thing I see people mess up a lot is the update frequency. If you only check the fuel once every second, the movement feels "chunky." You want to use something like RunService.Heartbeat or a very fast task.wait() loop so the fuel drains smoothly and the jetpack cuts out the exact millisecond the tank is empty.
Making the fuel actually drain
The "meat" of the roblox jetpack script fuel system happens inside the loop that controls the flight. Let's say you have a boolean variable called isFlying. When the player presses the key, isFlying becomes true.
Inside your loop, you'd have a bit of logic that says: "If isFlying is true and currentFuel is greater than zero, then move the player and subtract from the fuel."
Here's where it gets a little bit more advanced. You shouldn't just do fuel = fuel - 1. You should multiply your drain rate by the "delta time" (the time between frames). This makes sure that even if a player is lagging, their fuel drains at the same speed as someone with a super-fast PC. It's a small detail, but it makes the game feel way more professional.
Handling the UI and the visual side
A jetpack is no fun if you can't see how much gas you have left. Creating a UI for your roblox jetpack script fuel system is actually the most satisfying part. You just need a simple Frame for the background and another Frame inside it for the "fill" bar.
To make the bar move, you just change the Size of the inner frame based on the percentage of fuel left. The math is simple: CurrentFuel / MaxFuel. If you have 50 fuel left out of 100, the bar should be at 0.5 scale.
Pro tip: don't just snap the bar to the new size. Use TweenService to make it slide smoothly. It looks way better when the fuel gauge slowly creeps down instead of teleporting to the new position every frame. Also, you can change the color of the bar as it gets lower—start at green, go to yellow at 50%, and turn bright red when it's under 20%. It's a great visual cue for the player to start looking for a place to land.
Refilling the tank
Now, what happens when they run out? You need a way to get back in the air. There are two ways to handle this. You can either have the fuel regenerate slowly over time while the player is on the ground, or you can place "Fuel Canister" items around the map.
If you go the regeneration route, you just need another bit of logic in your script. If isFlying is false and the player is on the ground, start adding to the currentFuel until it hits the MAX_FUEL cap. Just make sure the regen rate is slower than the drain rate, otherwise, the jetpack basically becomes infinite again, which defeats the whole purpose.
Dealing with the physics
When the fuel hits zero, you need to make sure the player doesn't just hang in mid-air. You have to actively disable the BodyVelocity or LinearVelocity object you're using for flight. I've seen scripts where the fuel bar hits zero, but the player keeps floating because the developer forgot to tell the physics engine to stop.
When the fuel is empty, set your isFlying variable to false and immediately destroy or disable the force acting on the character. It's also a cool touch to add a "sputter" sound effect right before the fuel runs out to give the player a tiny warning.
Keeping things secure from exploiters
Since Roblox is a multiplayer platform, you have to worry about people trying to cheat. If you handle the entire roblox jetpack script fuel system in a LocalScript, a clever exploiter could just change their fuel value to 999,999 and fly forever.
To stop this, you really should keep the "truth" of the fuel value on the Server. The LocalScript handles the input (key presses) and the UI, but it sends a signal to the Server via a RemoteEvent. The Server then checks if the player actually has enough fuel to fly. If they do, the Server moves the player. If they don't, the Server says "no" and the exploiter stays grounded. It's a bit more work to set up, but it's the only way to keep your game fair.
Testing and common mistakes
Once you've got everything hooked up, you need to test it thoroughly. The most common bug I run into is the "Infinite Hover." This happens when the fuel drains to zero, but the code that checks for empty fuel only runs when a button is pressed. If the player just keeps holding the button, sometimes the check doesn't trigger correctly.
Always make sure your "out of fuel" check is robust. Another thing to look for is what happens if the player resets or dies while flying. You want to make sure the fuel resets properly when they respawn, or stays at zero if that's how your game works.
Don't be afraid to tweak the numbers. Maybe 100 fuel is too much, or maybe the jetpack drains too fast and makes the game frustrating. Playtest it, get some friends to try it, and adjust the DRAIN_RATE until it feels "just right."
Adding a roblox jetpack script fuel system is such a solid way to level up your game design. It turns a simple movement mechanic into a resource management game, and honestly, that's where the real fun is. Just keep your code clean, use your Tweens for the UI, and always remember to handle the physics on the server if you can. Happy building!