Sikorsky VSTOL/STOL Projects

[yasotay]

Also I would add to the drag discussion that anything hanging out the side of the aircraft decreases the hover efficiency of the rotorcraft over time. USN has "traditionally" wanted hover endurance for rotorcraft working ASW efforts. In fairness that philosophy may have since been superseded.

 

[TomcatViP]

That's why it is remarkable that the wb has moved from the belly to the flanks. We can notice an attention to bring an improvement in both airframe performances and serviceability.
If someone would have to make the history of this family of design, that would be an interesting point to notice...

 

[hesham]

I still don't find the original site for this report,

but I get it from Google-books,and here is with more Info.

A Technical Summary and Compilation of Characteristics and Specifications on Steep-gradient Aircraft

books.google.com.eg

 

[hesham]

I asked about these designs before,they were from Sikorsky;

Wind Tunnel Investigations of a High Speed Stowed Rotor Aircraft on JSTOR

Model rotor tests were conducted to investigate aeroelastic and aerodynamic behavior of a stowed rotor aircraft during stopping and stowing of the rotor. Result...

www.jstor.org

The High Speed Challenge for Rotary Wing Aircraft on JSTOR

This paper reviews the problems associated with developing a vertical takeoff and landing (VTOL) aircraft that has desirable helicopter-like attributes in hover...

www.jstor.org

https://www.secretprojects.co.uk/threads/vtol-aircraft-helicopter-projects-to-id.31775/#post-415731

 

[hesham]

From Aviation Week 1991.

 

[TomcatViP]

@hesham : do you have anything more on this particular design, that you posted back in the days? I find it a really interesting one.

Tailless, WiG(?), cushion landing system, compact cargo... Looks like a 21st century Marines wet dream!

 

[hesham]

@hesham : do you have anything more on this particular design, that you posted back in the days? I find it a really interesting one.

Tailless, WiG(?), cushion landing system, compact cargo... Looks like a 21st century Marines wet dream!

View attachment 690215

I will search in my files.

 

[hesham]

Unfortunately and as I expected,no caption for it,here is the file.

 

[yasotay]

@hesham : do you have anything more on this particular design, that you posted back in the days? I find it a really interesting one.

Tailless, WiG(?), cushion landing system, compact cargo... Looks like a 21st century Marines wet dream!

View attachment 690215

interesting idea - but, high disk loading, likely challenging lateral control, likely high weight fraction for the duct fans with shafting (from what source ?) or even if jet driven.

 

[TomcatViP]

@yasotay : I don't think the disk is there for lift. I think it's there for high AoA/High lift regime such as allowing for STOL. That would be why also the vertical is placed there, under the wing, directly in the forced airstream.

One problem of delta is the separation of airflown in their tip section at a moderate AoA (it's a variable of airstream speed and chord length). With the fan, that section could see an attached airflow, allowing the entire wing to be tilted up to en entire new region of angle of attack.

But that can be also only for roll ctrl.

Notice that it is not a VTOL.

Edit:
I forgot to mention that the wing probably tilt up like that of a Vought F-8.

@hesham : thank you for the pdf. Although I haven't been able to open it on my mobile so far.

 

[hesham]

Here is a picture showed CARA of US.
The VTOL aircraft fitted with retractable Roto on dalso and tail for VTOL, while needing level fly, the roto will autometically retracte and stored in airframe for reducing drag. The power mianly rely on one Jet and fan engine each side.

From Flightglobal 1966,with drawings to show how the engines worked
in lift and cruise stages.