orbiting large payloads with far

[endl]

my rockets keep flipping i have it working with smaller payloads using mechjeb (100% g turn starting at 1km ending at 70, acceleration caped)

ive tried smaller lifters spaming SAS but nothing changes.

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Edited November 25, 2014 by endl

[Starman4308]

my rockets keep flipping i have it working with smaller payloads using mechjeb (100% g turn starting at 1km ending at 70, acceleration caped)

ive tried smaller lifters spaming SAS but nothing changes.

You need to forget everything you learned about ascents. You also need to stop using MechJeb (unless you really tweak the gravity turn profile), because MechJeb is tailored to stock aero.

Step 1 of ascent: Make sure you have fins to drag center of lift/center of pressure behind center of mass. Also, aim for a launch TWR of 1.2-1.6. Also, in general, wobbly payloads and long fairings are bad news. Strut it up, try to make it wider, and if you must have a long vehicle, consider assembling in orbit.

Step 2 of ascent: At around 60-100 m/s, turn about 2-5 degrees in the direction you want to turn.

Step 3 of ascent: Wait for prograde marker to catch up.

Step 4 of ascent: Look Ma, no hands!

Step 5 of ascent: Once past 20-25 km, you can start to have your own ideas about where to point the rocket.

The thing about FAR is that, if you do not deviate far from prograde, you benefit from aerodynamic stability: if Center of Lift is properly behind CoM, aerodynamic forces will try to keep your rocket pointed in the direction of travel. If you deviate too far, you will start to flip over. This is most noticeable in the 10-20 km range, where you've built up a lot of speed but still haven't gotten through the thickest of the atmosphere.

[Alshain]

Starman4308 is dead on, but another problem you are having is your cargo is long and not strutted to the fairing, causing it to wobble out and then affect aerodynamics.

[Hodo]

I have to agree with Alshain and Starman. He couldn't be more right about everything he said there.

[endl]

ok seems like doing the turn even though gradual too early was the cause, i guess theres a middle ground for these turns depending on the length of the rocket.

[Vectura]

With FAR I generally go by the rule of start gradually turning when you are going at least 100m/s, and be around 45 degrees tilted over by around 12000m altitude.

[Lukaszenko]

Flip a fairing base upside down and place it on top as shown, and make sure "auto struts" are on. This will secure your payload.

[endl]

http://i.imgur.com/XE7ZvOy.jpg

Flip a fairing base upside down and place it on top as shown, and make sure "auto struts" are on. This will secure your payload.

that doesnt strut the payload it struts the fairings together thats it, also i never had a problem with my payload shifting that ss was from the moment the rocket was flipping over.

[Alshain]

that doesnt strut the payload it struts the fairings together thats it, also i never had a problem with my payload shifting that ss was from the moment the rocket was flipping over.

That was true, not true anymore. The latest version of ProcFairings has payload strutting. It's even in the title of the release thread "payload auto-struts". You can thank marce for that.

Search back in the thread and you will find this video.

Edited November 25, 2014 by Alshain

[Lukaszenko]

that doesnt strut the payload it struts the fairings together thats it, also i never had a problem with my payload shifting that ss was from the moment the rocket was flipping over.

I guess, but since the fairings are attached to the payload then in effect the payload gets strutted. Here's an example of what kind of payloads this lets you do launch:

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