Drag breaks should have "LIFT" or drag surfaces should affect attitude

[coreyfro]

Hey all,

Sorry about the image size, I don't know how to resize the image in this forum software.

This perfectly balanced potato of an entry vehicle should, with air-brakes extended, nose down to a proper orientation without guidance, kinda like a shuttlecock.

The design of this vehicle is otherwise completely unsound, I am just demonstrating that air brakes will not behave in an intuitive way.

If air breaks were given a larger lift value, when extended, this would be fixed.

That's all.

Edited July 11, 2015 by coreyfro

[Skalou]

i don't know if the pics demonstrate well your problem because Laythe has a max athmosphere of 50 000m, so at 46 000 you have really low atmospheric pressure (look the blue bar under the altitude) and so low aerodynamic forces that won't be enought to make you turn fast.

also your trajectorie seems very very hard (vertical) , not the best for slowing.

also air-brakes are here to produce max drag ,not lift.

Edited July 11, 2015 by Skalou

[coreyfro]

Suggesting "Lift" is based on two things:

1. It's a game mechanic.

2. It's the game mechanic that Squad is using, look at the part in KSP, you'll see it has a lift rating.

I think, for the purposes of simulating the affect drag has on attitude, this value needs to be higher.

I will test lower trajectories. I have tested them, before, but I will post evidence.

[Nothalogh]

Use the air brakes asymmetrically, such as only on the top rear for a nose heavy vehicle. This will cause a nose up attitude upon application of brakes.

Take advantage of the lifting body, and build accordingly

[Wjolcz]

i don't know if the pics demonstrate well your problem because Laythe has a max athmosphere of 50 000m, so at 46 000 you have really low atmospheric pressure (look the blue bar under the altitude) and so low aerodynamic forces that won't be enought to make you turn fast.

also your trajectorie seems very very hard (vertical) , not the best for slowing.

also air-brakes are here to produce max drag ,not lift.

1. It's not Laythe.

2. I think he's talking about how airbrakes should auto-orient the craft nose-first because they are at the back, but (as showed in the pictures) they don't.

[Skalou]

1. maybe kerbin desert

2. it works as intended, but if there is low density, you will have low aero forces. at lower altitude it works well.

it produces lift but it's not the main feature, i think airbrakes are here to produce a maximum of drag, not having a good L/D ratio.

Edit:

coreyfro, i suggest you to try it on a Kerbin reentry with this kind of orbit: AP = 80 000m; PE= 35 000m

Edited July 13, 2015 by Skalou

[Red Iron Crown]

Air brakes can and do affect attitude, by default they are set to control yaw and pitch when installed. They are of course more effective the further they are from the CoM, which I suspect is why they're not having the intended effect on the craft pictured. Especially if there is fuel remaining in the tank with the brakes on it and the other tank is dry (can't really tell from the pic).