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Boeing AH-64D Apache Longbow


Yaeah

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I always thought that was a curiously complex tail rotor for an otherwise conventional attack helo.  I remember way back in my high-school model building days, puzzling over why the tail rotor blades that shipped with my 1/48 scale Apache kit were obviously wrong.

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58 minutes ago, Yaeah said:

good catch, changed the tail rotors to contra-rotating

They don't contra-rotate. They're just set at a non-90-degree angle to avoid radar reflections and reduce its radar cross-section. 

But that's a quibble. It's an impressive replica. :D

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22 minutes ago, Vanamonde said:

They don't contra-rotate. They're just set at a non-90-degree angle to avoid radar reflections and reduce its radar cross-section. 

But that's a quibble. It's an impressive replica. :D

bruh

I’ll have to re-fix it later lmao

Edited by Yaeah
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1 hour ago, Vanamonde said:

They're just set at a non-90-degree angle to avoid radar reflections and reduce its radar cross-section. 

Not sure about how it affects its radar cross-section, but the primary reason it was designed with a 55-degree separation vs the typical 90-degrees in 4-bladed tail rotors is to increase tail rotor efficiency and performance.  The 55-degree separation, coupled with the lateral offset of each blade "pair" ensures that the second set of blades operates in clean air, instead of operating in the wake of the first pair of blades.  It's like following close and to the side of another aircraft, avoiding it's wake.  However the further back and/or closer to its tail you are, the greater chance you will encounter turbulent air trailing behind its airfoil surfaces, which will expand the further back you go.

Another common misconception was that it was designed to make it more quiet.  While avoiding the wake of leading pair of blades does lead to less noise, this is a convenient by-product of the aerodynamic design, rather than the primary reason for the design implementation.

Edited by Raptor9
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On 2/20/2020 at 5:47 AM, Raptor9 said:

Not sure about how it affects its radar cross-section, but the primary reason it was designed with a 55-degree separation vs the typical 90-degrees in 4-bladed tail rotors is to increase tail rotor efficiency and performance.  

Very interesting - thanks for sharing! Makes me curious then about why such a design isn't more common. Maybe something to do with mechanical complexity?

On 2/20/2020 at 6:23 AM, XLjedi said:

Which all reaffirms my decision to not build replicas... but that is a fine looking craft. 

Well done!

On the contrary, this is the sort of thing I live for when building replicas. You notice a small detail, then you go down a rabbit hole figuring out why that bit made it onto such a highly engineered machine. 

 

Disregarding tail-rotor quibbles, this is a lovely replica! The solar panels really work well here, and the fuselage shaping works really well too. 

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@Servo  No, I avoid em because there will always be someone to point out a flaw or better version... 

Then arguments ensue over who's replica is the bestest-est-est.  I've actually seen some people say stuff like, "That's the best replica I've ever seen!"  Trying to complement the builder and then 2 or 3 other twits chime in with stuff like "Really?  Then you haven't seen my version: [link], [link], [link]"  

(to be clear, no one has done anything like that on this thread)

...but it can get stupid quick.

Edited by XLjedi
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