physics laws are changed?

[f.pelosa]

hi,

I've been playing for some time on v.0.90 and really enjoyed the game.

I recently tried out v1.04 and I am having a lot of problems in keeping any rocket in vertical position, and in parachuting back to Kerbin.

Here's my experience:

1) rocket in vertical position:

I am at the very beginning of the 'science' game, so I am playing with the basic rocket parts: my rocket is a simple payload with an engine. I enable SAS and full throttle before take off, then I press 'space' and I quickly ramp up to several m/s. As soon as I try to orient my rocket slightly to the east (I usually aim to a 80 degree angle as soon as I reach 100m/s) and as soon as the orientation of the rocket exits the yellow circle that shows the prograde direction, the rocket flips upside down.

There's no possibility to set it nose-up again: the only option is to wait for the ascending velocity to decrease to less than 100m/s. Then, once I can finally turn my nose up, I go full throttle and unless I aiming at the perfect centre of the prograde indicator, flip upside down again..

2) parachute:

if I go up 10-15000m, then detach the engine and try to descend with a parachuted payload only, the parachute breaks and I crash on land. In v0.90, you could even deploy your chutes in space, enter the atmosphere, and they would still work. In v1.04, I couldn't find a way to use the parachutes if I start my descend above (say) 10000m.

Thanks for your comments.

AC

Edited October 15, 2015 by f.pelosa

[xtoro]

Don't go full throttle until you're at least 10km up. Until then keep your speed below 300m/s. The new aero adds difficulty. Also, try putting fins at the bottom to create some drag that will keep the bottom behind all the weight. Think of throwing a dart. And dont turn too sharply or you'll flip.

- - - Updated - - -

You can press F12 while you fly and see the aerodynamic forces at play.

[DeMatt]

1) rocket in vertical position:

I am at the very beginning of the 'science' game, so I am playing with the basic rocket parts: my rocket is a simple payload with an engine. I enable SAS and full throttle before take off, then I press 'space' and I quickly ramp up to several m/s. As soon as I try to orient my rocket slightly to the east (I usually aim to a 80 degree angle as soon as I reach 100m/s) and as soon as the orientation of the rocket exits the yellow circle that shows the prograde direction, the rocket flips upside down.

There's no possibility to set it nose-up again: the only option is to wait for the ascending velocity to decrease to less than 100m/s. Then, once I can finally turn my nose up, I go full throttle and unless I aiming at the perfect centre of the prograde indicator, flip upside down again..

That would be because your rocket has more drag at the front than it does at the rear. Try adding a set of fins to the rear.

2) parachute:

if I go up 10-15000m, then detach the engine and try to descend with a parachuted payload only, the parachute breaks and I crash on land. In v0.90, you could even deploy your chutes in space, enter the atmosphere, and they would still work. In v1.04, I couldn't find a way to use the parachutes if I start my descend above (say) 10000m.

It's not specifically altitude that burns the parachute, it's the speed. If you right-click on the parachute while in flight, the popup shows a warning as to whether the parachute can be safely deployed. Generally 250m/s is safe, but a particularly aerodynamic payload may still be going too fast when it reaches the ground.

Solution? Make your payload less aerodynamic (once detached). Airbrakes, fins, odd shape under a fairing, whatever works. Drogue chutes are also good - they can be deployed at faster speeds.

[NathanKell]

For 1, please post a picture of your rocket. That said, trying to turn 10 full degrees is a bit much to do at a time, try going to say 88 degrees at 50m/s, 86 at 60, 84 at 70, and so forth.

For 2, you need to wait until you're going < 250m/s to deploy safely on Kerbin. Any faster than the parachute will shred/melt. Right-click on the parachute part during flight, and in the menu that pops up, it will say whether it is safe, risky, or unsafe to deploy right then.

[tseitsei]

1) yeah atmosphere changed. Now you need some winglets/fins to the back of the rocket to increase drag at the back to prevent flipping. You also need to build your rocets to look more like rockets and actually be somewhat aerodynamical. You also need to do yourn turning VERY slowly and gradually while in dense atmosphere. Try keeping inside the prograde circle as much as possible.

2) you cant deploy parachutes before you are slower than ~250-300m/s. They will break.

[Clipperride]

Keeping your heading at the edge of, but still within the prograde marker circle when you are low in the atmosphere will help.

If you think of a dart, even when thrown fins first, it will generally still hit the board point first. That's because it has its COM towards the point end and a lot of drag at the other end. The closer to that ideal you can get with your rocket design, the more stable it will be.

[Snark]

Regarding the parachutes: As the previous posters have mentioned, you need to be going under ~250ish m/s or they'll get destroyed. One way to help guard against this at design time in the VAB is to set the parachute's minimum deploy pressure from the default 0.04 atmospheres up to something like, say, 0.5 atmospheres. It's not a perfect solution-- some ships may still be going faster than that when they get to the 0.5atm level, and there are some mountains on Kerbin that poke higher than that-- but it works pretty well for me.

Also, you can use drogue chutes; there's actually a reason to use them now (there wasn't really, pre-1.0). Their minimum opening speed is roughly double that of the "regular" parachutes, so you can pop them when you're going nearly 500 m/s and let them slow you down before you hit the other chutes.

A tip while flying: If you right-click on a parachute, its menu has an indicator saying whether deployment would be Unsafe, Risky, or Safe. Wait until it says "Safe" to deploy.

[f.pelosa]

thanks all guys

[Red Iron Crown]

I've found fine controls helpful to avoid overturning the rocket during the initial tip. My launch procedure has changed from T, Z, Space to T, Z, CapsLock, Space.

[eddiew]

Once you have launch stabilisers, it can help to build the rocket on a 1-notch incline in the VAB. Easiest gravity turn ever (Unless you're low on thrust, in which case you'll fall over before getting up to flight speed.)

[Sharpy]

With enough fin surface it's about impossible to flip the rocket as it will fight back towards the prograde direction. It's still possible to fly without fins or with some very weird, non-aerodynamic configurations, but then you really shouldn't swing outside the prograde marker to avoid flipping.

(example of such configuration - a 3-part rocket consisting of Rhino, the large Kerbodyne tank and any probe core.)

But yeah, some fins of size roughly proportional to the rocket (e.g. use the Delta Wing for fins on anything big), and rockets become quite unflippable.

[FlyingPete]

Unless you're in KSP- then they changed after 0.90