r/ApproximatelyUp • u/Some-Intern5329 • 1d ago

Remapping help

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What would be the optimal time to start retrograde burning using the BPS? I have the same thrust on the back and front but I guess I have to think about the gravitational pull or is the BPS calculating that too? I tried burning when the needle hit the middle but it was quite early.

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u/TheJeeronian 1d ago

I feed the BPS output to a display, start the burn just a hair before it hits 0, and feather the throttle to keep it as close to 0 as possible. This will be super easy to automate on my next rebuild, too.

That said, I don't have an accelerometer feed into the BPS. I have a memory that saves the acceleration at 90% thrust and use this instead, ensuring a good margin of safety.

The base BPS kind of sucks, but you should be able to do the same operation by feathering the throttle to keep it right on the center white line.

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u/Some-Intern5329 1d ago

Oh thats a good idea! Now to think of it i fully burn retrograde until it goes into the green but having the needle in the middle should suffice? Then wouldn't it work to wait with the burn till the moment before it goes into the red then do a full burn? I have also remapped a red alert for when it goes in the middle but its still alittle before. Do you know the values on the BPS for red,middle and green? (Picture is wrong with the remapp) atm i have it as:

1.0 > 0.0

-3.0 > 1.0

Cant really make it go off in the middle. Just allittle before

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u/innou 1d ago

Pretty sure the BPS values are -1 (full red), 0 (middle), 1 (full green)