• 0
Sign in to follow this  
Followers 0
Ninadragonborn

how to make medium or long range ICBM (i am playing Real Solar System)

Question

i haw found this after searching the maximum altitude for giving range of ICBM 

but the problem is when you launch the missile eastward the delta V required

can easily be calculated

but when missile is launched westward there goes the problem drag increases significantly 

and also i am talking about solid fuel because in real life almost all ICBM are solid fuel 

except for Russian ICBM 

so how you design something that can achieve medium or long range for both eastward and westward launch 

that have significant drag losses 

is it have something to do with launch trajectory in first seconds of launch or something else 

i have designed ICBM but this drag losses between eastward and westward have made thing confusing  

and this are the flight altitude and delta V required for giving range

https://ibb.co/djiTCa

https://ibb.co/gZR4kv

Share this post


Link to post
Share on other sites

5 answers to this question

  • 0

There shouldn't be any differences in drag between eastward and westward launches. The problem you're probably running into is the rotation of the Earth. 

Just give it enough dV for westward launches, and then use a higher parabola for eastward launches.

2 people like this

Share this post


Link to post
Share on other sites
  • 0
1 hour ago, sevenperforce said:

There shouldn't be any differences in drag between eastward and westward launches. The problem you're probably running into is the rotation of the Earth. 

Just give it enough dV for westward launches, and then use a higher parabola for eastward launches.

E i know that its the drag do to the rotation of earth that's why almost all orbital rocket are launched eastward not westward you lose a lot more delta v do to gravity drag when launching westward but i want to know when they say a rocket have a range of 5500 km is it for both eastward and westward because there is a significant different in drag losses toward west then toward east because you moving against earth gravity not with it 

and since almost all ICBM use solid fuel which i also use i want to know how they calculate this difference in gravity drag toward east or west because its a huge difference in delta v     

Share this post


Link to post
Share on other sites
  • 0
31 minutes ago, Ninadragonborn said:

E i know that its the drag do to the rotation of earth that's why almost all orbital rocket are launched eastward not westward you lose a lot more delta v do to gravity drag when launching westward but i want to know when they say a rocket have a range of 5500 km is it for both eastward and westward because there is a significant different in drag losses toward west then toward east because you moving against earth gravity not with it 

and since almost all ICBM use solid fuel which i also use i want to know how they calculate this difference in gravity drag toward east or west because its a huge difference in delta v     

The rotation of the Earth has a lesser effect for ICBM launches, because you're not going to orbit; you're going to a target that is on the Earth's surface so it is also rotating. However, if your ICBM is large enough to hit a meaningful fraction of orbital velocity, then the centrifugal element can negate part of Earth's gravity, decreasing gravity drag on your ICBM during the boost phase.

However, I'm afraid that calculating this is extremely difficult. I've done it before, in advanced classical mechanics, but it involves creating a system of equations to model the differential rotation of the Earth as a non-inertial reference frame. Physicists were doing it with slide rules back during the Cold War. It's extremely advanced math and it's different for every possible trajectory. Adding staging to the mix makes it even more complicated.

Share this post


Link to post
Share on other sites
  • 0

Posted (edited)

3 hours ago, sevenperforce said:

The rotation of the Earth has a lesser effect for ICBM launches, because you're not going to orbit; you're going to a target that is on the Earth's surface so it is also rotating. However, if your ICBM is large enough to hit a meaningful fraction of orbital velocity, then the centrifugal element can negate part of Earth's gravity, decreasing gravity drag on your ICBM during the boost phase.

However, I'm afraid that calculating this is extremely difficult. I've done it before, in advanced classical mechanics, but it involves creating a system of equations to model the differential rotation of the Earth as a non-inertial reference frame. Physicists were doing it with slide rules back during the Cold War. It's extremely advanced math and it's different for every possible trajectory. Adding staging to the mix makes it even more complicated.

yes its really complicated i created a 2 stage ICBM with 5500 km range  i have launched it from middle east to Ireland but because i was going against gravity it used 8000 m/s delta v will i launched it from middle east toward china it used only 6000 m/s delta v for 5500 km so 2000 m/s gravity drag losses 

however i have done a lot of study in Wikipedia but it seems in other to overcome gravity losses that much the trust versus ratio must increase a lot up to 4 g for example if what i have learned will help overcome the gravity drag then it mean i should have  acceleration of 40 m/s on start for my boost stage or first stage to decrease the gravity drag to minimum 

i do not know i have not tested this but i think i should do that and see if its right 

the problem is i need to find good enough and powerful solid fuel engine 

Edited by Ninadragonborn

Share this post


Link to post
Share on other sites
  • 0
3 minutes ago, Ninadragonborn said:

yes its really complicated i created a 2 stage ICBM with 5500 km range  i have launched it from middle east to Ireland but because i was going against gravity it used 8000 m/s delta v will i launched it from middle east toward china it used only 6000 m/s delta v for 5500 km so 2000 m/s gravity drag losses 

however i have done a lot of study in Wikipedia but it seems in other to overcome gravity losses that much the trust versus ratio must increase a lot up to 4 g for example if what i have learned will help overcome the gravity drag then it mean i should have  acceleration of 40 m/s on start for my boost stage or first stage to decrease the gravity drag to minimum 

i do not know i have not tested this but i think i should do that and see if its right 

the problem is i need to find good enough and powerful solid fuel engine 

Well, for one thing, the higher your TWR is, the less of an impact gravity drag will have. But when we are talking about near-orbital velocities, it's definitely going to be a factor.

Another issue is the Coriolis effect, which the previously-discussed math models.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0