General aviation/airplane news and chat

[A380]

One blade would be the theoretically most efficient if not the most practical.

More blades are used when the load on the rotor disk is too great for fewer blades. To generate a relatively greater lift the speed of the advancing tip would get very high compared to the speed of the retreating tip - the 'Advance Ratio'. If this ratio gets out of limits then the retreating blade will stall. Even if the retreating blade doesn't stall then the advancing blade will start to hit Mach Buffet in the transonic regime and then that blade would stall.

To get around this and reduce tip speed, more and smaller blades are used. Their are also logistical and size constraints where more, smaller blades would be preferred over fewer, larger.

 

[_Russ_]

One blade would be the theoretically most efficient if not the most practical.

Yea, well sort of. I've read a good few arguments for it mostly around being further behind the previous blade for a given rpm, but well.
I find this south african bloke always does good summations of subjects on the lighter side of flying that are very accessible for the curious with little background (in case there are some non air-heads reading this)
I remember the control line speed models going through a phase in the 70s-80s with single blade props turning fecking silly rpm, weird looking things, One wing, one horizontal stabiliser and one prop blade

edit, I put it stoopidly, of course a blade is always the same distance behind the other one regardless of rpm, what I mean is further behind in time not space for a given rpm, but dont really know how to put it as I've just had a big piece of my special cake about an hour ago

 

[pseudonarcissus]

View attachment 456008

Cool, is that one of the cards they came out of a box of PG Tips?

 

[pseudonarcissus]

I took these photos on the USS ORLECK, a Gearing Class destroyer..I guess an early torpedo carrying gyrocopter drone . I’m guessing from the 70s

 

[pseudonarcissus]

I took these photos on the USS ORLECK, a Gearing Class destroyer..I guess an early torpedo carrying gyrocopter drone . I’m guessing from the 70s
View attachment 456341View attachment 456342

Gyrodyne QH-50 DASH​

 

[pseudonarcissus]

Gyrodyne QH-50 DASH​

60s

 

[Saul Goodman]

I took these photos on the USS ORLECK, a Gearing Class destroyer..I guess an early torpedo carrying gyrocopter drone . I’m guessing from the 70s
View attachment 456341

Looks like Gyrodyne DSN-3/QH-50C anti-submarine drone from the early 60s.
Not a gyrocopter.

 

[pseudonarcissus]

Looks like Gyrodyne DSN-3/QH-50C anti-submarine drone from the early 60s.
Not a gyrocopter.

So what happened to drones in naval warfare if suddenly they’re a great threat in the Black Sea if you are Russian, or the Red Sea if you are anyone else? These things are older than us!

 

[_Russ_]

So what happened to drones in naval warfare if suddenly they’re a great threat in the Black Sea if you are Russian, or the Red Sea if you are anyone else? These things are older than us!

In the medium-large segment t's more to do with the massive improvements in the systems on board than the vehicles themselves, development of guidance and sensor tech and its miniaturisation, which itself together with small brushless motor and battery advances has brought the smaller sized vehicles into usefullness also