As a high school student, I'm incredibly impressed and inspired by your work! I remember your last video like it was yesterday, and its amazing that you continued it with so much effort! Good job!
There should be no holding in a true gravity turn. Any time spent firing away from prograde means fuel wasted fighting extra drag, you ideally want to fire to prograde only. So, while this is impressive work, i wouldn't label it perfect gravity turn.
Instead of locking, wouldn't you want to have a smooth gradient? It seems you're in the realm of trying to find pockets of optimal performance kinda like fuel economy for trucks at different speeds/gears/etc. So in this case, instead of locking at an angle, you would want to just lock a _range_ of angles at certain points in the turn. Let the rocket find pockets of efficiency as it goes through the changes in drag to air density.
I liked your reference to Kerbal Space Program. The type of gravity turn I like is the "Zero Lift" gravity turn and it works well in KSP and is easy to program in Kerbal Operating System. I suspect they used something very close to a zero lift gravity turn when launching the Saturn V.
I start using the gravity turn mostly to get through the atmosphere. After that, it's some fraction of the gravity turn. Yet not sure what the optimum is...
bro why dont you provide the math on how one can calculate how long and how mutch to pitch over and how long to stay in gravity turn... that would make the video so helpful. So far it doesn't get someone who is working on the same problem mutch further...
Re: gravity turn is perfect? Nope. Not for low orbits and low TWR. Optimized trajectories often overshoot their target apoapsis by hundreds of km and then have lightweight upper stages that burn at very low TWR with significant cosine losses, but the mass ratio advantage more than makes up for it.
Not true. You had it right to begin with. If you LITERALLY let gravity do the turn, then you don't need to gimbal. In fact, you CAN'T. Gimbaling FIGHTS the gravity turn... by either deviating above or below what would happen if left alone. Alignment in a gravity turn is caused by having the center of pressure AFT of the center of mass. A gravity turn is used ONLY when engines or flight surface controls are NOT allowed to alter the flight path. If they are, then the rocket is simply in active control, and gravity is not what is actually controlling the turn of the rocket (through gravity/drag/aerodynamics, etc obviously still have an effect on the trajectory).
Actually, that’s the change I made for this video. In the original I was brute forcing the turn and ignoring the natural trajectory. I was just changing the angle of the rocket at a constant rate. In this video, I mostly do a gravity turn with a brief “manual” gimbal to initiate the turn, and an angle hold raise my apogee
@@ConHathy Just realize that while a gravity turn is efficient in TURNING a rocket... it almost NEVER is efficient in achieving orbit... Why? Because nearly no gravity turn actually gets you into orbit at all. Almost every possible gravity turn will cause failure to achieve orbit. The only time to use a gravity turn is: when you don't have any means of guidance. If you have guidance... then you are simply making a guided turn.
@@RyderSpearmann Yet SpaceX are using gravity turn on just about every F9 flight they make. They vary the angle and kickpoint to get different aggressive or gentle turns, but it's GT all the same. I have telemetry from five different flights and can match each one of them withing a percent or two with a gravity turn. Heck, they even call it a gravity turn. Yes, you CAN make a guided gimballed flight all the way up but you won't have much fuel left.
@@ritcheycretien9875 they ALL are fully gimbal’d. Gravity turns are only for rockets that have no guidance. Anyone saying otherwise is misusing the term. All modern rockets simply pick a flight path and stay on it.
@@ritcheycretien9875 I think you are confusing a gravity turn with a “gravity turn trajectory”. The TRAJECTORY is an IDEAL trajectory that could IN THEORY allow the rocket to proceed fully unguided… letting gravity do the work. This is how hobby rockets fly. It’s *POSSIBLE* (like the lottery) that no control inputs are required by the guidance system… and the engines/control surfaces stay exactly at zero degrees for the entire flight (after pitch over), but like the lottery, I don’t see that ever happening.
As a high school student, I'm incredibly impressed and inspired by your work! I remember your last video like it was yesterday, and its amazing that you continued it with so much effort! Good job!
Thank you, that means a lot! It has been a fun project but there’s still a ton of complexity that I could add
"They start vertical and then go horizontal"
Instructions unclear, tilting the rocket 90 degrees at max Q.
I'm working on a similar simulation for a college project, so thank you for helping me get a better understanding of how this works.
Cool video! I was thinking about this the other night and wanted to learn more and found your video
There should be no holding in a true gravity turn. Any time spent firing away from prograde means fuel wasted fighting extra drag, you ideally want to fire to prograde only. So, while this is impressive work, i wouldn't label it perfect gravity turn.
Instead of locking, wouldn't you want to have a smooth gradient? It seems you're in the realm of trying to find pockets of optimal performance kinda like fuel economy for trucks at different speeds/gears/etc. So in this case, instead of locking at an angle, you would want to just lock a _range_ of angles at certain points in the turn. Let the rocket find pockets of efficiency as it goes through the changes in drag to air density.
I liked your reference to Kerbal Space Program. The type of gravity turn I like is the "Zero Lift" gravity turn and it works well in KSP and is easy to program in Kerbal Operating System. I suspect they used something very close to a zero lift gravity turn when launching the Saturn V.
Negative drag :)
Let’s all it “Dark drag”… we need it lol
I start using the gravity turn mostly to get through the atmosphere. After that, it's some fraction of the gravity turn. Yet not sure what the optimum is...
I would say optimize on periapsis altitude rather than minimum fuel to orbit. This allows the system to learn without constraining it as harshly.
Hi there! Is this simulation available anywhere?
Well explained. ☺️⬆️↗️➡️
I exactly know how it feels like. Guess who tried the same for Vega for 500km SSO 😆
How do I cite you in my thesis work :D Nice video
knowledgeable
bro why dont you provide the math on how one can calculate how long and how mutch to pitch over and how long to stay in gravity turn... that would make the video so helpful. So far it doesn't get someone who is working on the same problem mutch further...
have you simulated a boost back burn yet? 😂
Oh no, I think I need to learn a faster language if I want to do anything with more variables
See Gravity's Rainbow by Pinchon
Re: gravity turn is perfect?
Nope. Not for low orbits and low TWR. Optimized trajectories often overshoot their target apoapsis by hundreds of km and then have lightweight upper stages that burn at very low TWR with significant cosine losses, but the mass ratio advantage more than makes up for it.
u seem smart
Not true. You had it right to begin with.
If you LITERALLY let gravity do the turn, then you don't need to gimbal. In fact, you CAN'T. Gimbaling FIGHTS the gravity turn... by either deviating above or below what would happen if left alone. Alignment in a gravity turn is caused by having the center of pressure AFT of the center of mass.
A gravity turn is used ONLY when engines or flight surface controls are NOT allowed to alter the flight path. If they are, then the rocket is simply in active control, and gravity is not what is actually controlling the turn of the rocket (through gravity/drag/aerodynamics, etc obviously still have an effect on the trajectory).
Actually, that’s the change I made for this video. In the original I was brute forcing the turn and ignoring the natural trajectory. I was just changing the angle of the rocket at a constant rate. In this video, I mostly do a gravity turn with a brief “manual” gimbal to initiate the turn, and an angle hold raise my apogee
@@ConHathy Just realize that while a gravity turn is efficient in TURNING a rocket... it almost NEVER is efficient in achieving orbit...
Why? Because nearly no gravity turn actually gets you into orbit at all.
Almost every possible gravity turn will cause failure to achieve orbit.
The only time to use a gravity turn is: when you don't have any means of guidance.
If you have guidance... then you are simply making a guided turn.
@@RyderSpearmann Yet SpaceX are using gravity turn on just about every F9 flight they make. They vary the angle and kickpoint to get different aggressive or gentle turns, but it's GT all the same. I have telemetry from five different flights and can match each one of them withing a percent or two with a gravity turn. Heck, they even call it a gravity turn. Yes, you CAN make a guided gimballed flight all the way up but you won't have much fuel left.
@@ritcheycretien9875 they ALL are fully gimbal’d. Gravity turns are only for rockets that have no guidance. Anyone saying otherwise is misusing the term.
All modern rockets simply pick a flight path and stay on it.
@@ritcheycretien9875 I think you are confusing a gravity turn with a “gravity turn trajectory”.
The TRAJECTORY is an IDEAL trajectory that could IN THEORY allow the rocket to proceed fully unguided… letting gravity do the work. This is how hobby rockets fly.
It’s *POSSIBLE* (like the lottery) that no control inputs are required by the guidance system… and the engines/control surfaces stay exactly at zero degrees for the entire flight (after pitch over), but like the lottery, I don’t see that ever happening.