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Haruspex

Folding grid fins

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Falcon_9_first_stage_in_hangar.jpg

 

Currently, the only folding set of control surfaces we have in stock are airbrakes. They would be totally fine (and they were for a while!), but some time ago they got their heat tolerance nerfed into the ground. Now deployed airbrakes do not survive Kerbin reentry.

My suggestion is to either bring the airbrakes' heat tolerance to that of MK3 equipment (2400-2600 K), or, better yet, to add a set of proper grid fins into the stock tech tree.

Thank you!

 

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Air brakes and grid fins are completely different animals.  I agree airbrakes would be nice if they stood up to the heat a little better.  Grid fins are used to steer a craft, they're used on large guided munitions and of course spacex, as they have more 'lifting' surface as compared to regular fins of the same size, but do add more drag. 

The fins are available from a number of mods already I believe, but I don't ever see these getting incorporated into stock.

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56 minutes ago, Gargamel said:

Air brakes and grid fins are completely different animals.  I agree airbrakes would be nice if they stood up to the heat a little better.  Grid fins are used to steer a craft, they're used on large guided munitions and of course spacex, as they have more 'lifting' surface as compared to regular fins of the same size, but do add more drag. 

Stock air brakes can affect yaw, roll and pitch and thus can actually be used to some degree to control the vehicle. They aren't intended for this, of course, and that's why a proper set of deployable control surfaces is a much better option. So there's really two intersecting problems here: (nearly)unusable airbrakes that explode if you try to actually use them to slow down, and lack of folding flaps or fins that could be extended as needed. Using stock airbrakes in this capacity is a cheap hack, but even this is now impossible.

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Would be nice to see deployable grid fins. Regular fins are a pain on the way up as they don't fold away and so mess with the CoL of the rocket.

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2 hours ago, Frozen_Heart said:

Would be nice to see deployable grid fins. Regular fins are a pain on the way up as they don't fold away and so mess with the CoL of the rocket.

It's not entirely impossible to build folding fins that deploy permanently on a stock hinge. They can then be keyed to control pitch and yaw, though not necessarily roll. 

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10 minutes ago, sevenperforce said:

It's not entirely impossible to build folding fins that deploy permanently on a stock hinge. They can then be keyed to control pitch and yaw, though not necessarily roll. 

Even if you came up with a mechanism to fold stock fins, that doesn't effect the amount they effect the CoL and so the rocket will still flip if they are placed at the top. The game doesn't simulate something being folded away from the airflow.

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9 minutes ago, Frozen_Heart said:

Even if you came up with a mechanism to fold stock fins, that doesn't effect the amount they effect the CoL and so the rocket will still flip if they are placed at the top. The game doesn't simulate something being folded away from the airflow.

Sure it does. If a control surface is folded flush to the side of the rocket and control authority is set to off, it will have negligible effects on your center of pressure (unless you're doing some really wild gravity turn). An action group can unfold the grid fins, causing them to redock to the vehicle and enable control authority, and you'll have your control surfaces operational.

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