Something seems fishy, they told in the paper that grid fins need to pull less for same aoa compared to planar fins, hence added drag should be less when turning compared to planar fins, but here the drag coeffecient across all aoa is equidistant, something is wrong…
no its not, that is fin AOA not missile AOA
I don’t think this comparision is that usefull, the planar fins taken is wierd, it’s not that long but a bit wide, whereas the grid fin taken is much bigger than the ones on r77.
Except that it can?
the comparison is between planar fins of a somewhat normal design and grid fins of the same area, which is the ideal options for a paper like this
Size matters too, different sizes can give different results, as mentioned in the paper
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yes but how can you compare two things if you change a bunch of variables
ideally you only change one variable which is why they changed the type of fin without changing the size
They haven’t kept the reference area the same though, meaning the grid fins’ lift and drag coefficient are not quite comparable. Also I reckon the grid fins are pretty rough models without having been modified for supersonic movement.
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A screenshot of page 90 of ADA426637.
Found here:Defense Technical Information Center
This research in part discusses how they attempted to reduce said drag
According to the initial statement it seems like the grid fins can pretty much have low AoA to achieve turns which would be very favourable for a missile against defensive manoeuvres.
what statement are you referring to? the abstract or something in the paper?
The subtract is just a statement based off the previous studies in the paper. This does align with the other document.
at that point youre nitpicking in order to discredit.
yeah thats what abstract means, but i cant see where it says what youre saying
One thing you guys miss is that to create an equal amount of moment on the missile the grid fins have to move a LOT less than a planar fin, also there is an unclassified and unrestricted nato grid fin study out there.
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There’s a graph of hinge movement to missile AoA somewhere in there and also it said hinge movement is lower compared to normal fins. Basically hinge movement is parallel to grid AoA and that it requires less to achieve more missile turn.
thats a given, but if that was relevant enough to counteract the increased drag that paper wouldnt exist, the lower hinge movement is one of the reasons they were picked in the first place as ussr struggled with actuators as far as i know
They basically only had AoA vs drag which is useless cause that doesn’t mean the effect of the grid being in say 10 degree is the same as a normal fin.
yes but I am just saying it means the drag to AoA in previous graphs are pretty useless.
They only show AoA to drag so pretty useless. The so called 4 times as much drag is not useful.
i agree that it is definetly lacking but fully discrediting it is unfair i feel like.