Tri-Service VTOL Transport proposals (XC-142 competition)

[Orionblamblam]

Propriety got the better of me.

I know the forum has rules, but sometimes... man, ya really just want to let fly. An apparently serious design with (apparently) serious design flaws is one of those times. This vehicle, at least based on the photos, not only have no roll control in hover but also no yaw control. The exhaust vanes on the underside can probably provide some fore-aft control, thus pitch control, but otherwise... shrug.

 

[taildragger]

Enclosure 1 states: "The vehicle is controlled in vertical flight through control vanes in each air duct and in the engine exhaust ducts. In horizontal flight, control is achieved through a conventonal rudder/elevator system plus the control vanes in the exhaust ducts" The turbine exhaust ducts can be seen extending aft of the trailing edge in the cutaway view, where they look to be asymmetrically located. Not saying it would work, but they did have a 3-axis control mechanism defined.

 

[Yellow Palace]

I would hazard a guess that inability to provide a credible solution to the roll control problem contributed to the seemingly-rapid demise of this particular configuration.

 

[TomcatViP]

There is also a drastic problem with forward to Vertical flight transition:
- let's admit that the airfoil shape of the fuselage can provide enough lift in forward flight as assumed.
- Lift occurs thanks to a large negative pressure field ontop of the wing
- At the onset of vertical transition, the lift fans are switched-on... Ruining your negative pressure field sucked into the engine (you'll effectively get an over-pressure field due to ram effect!)
- deprived of any lift (and in fact submitted to a negative lift flow field), the vehicule falls down rapidly, reaching quickly a sink rate frome which it can not recover (the more power the more negative lift generated until max power setting is achieved).

 

[taildragger]

There is also a drastic problem with forward to Vertical flight transition:
- let's admit that the airfoil shape of the fuselage can provide enough lift in forward flight as assumed.
- Lift occurs thanks to a large negative pressure field ontop of the wing
- At the onset of vertical transition, the lift fans are switched-on... Ruining your negative pressure field sucked into the engine (you'll effectively get an over-pressure field due to ram effect!)
- deprived of any lift (and in fact submitted to a negative lift flow field), the vehicule falls down rapidly, reaching quickly a sink rate frome which it can not recover (the more power the more negative lift generated until max power setting is achieved).

Did that phenomena affect fan-in-wing aircraft like the Ryan XV-5?
(It's impossible to "suck a negative pressure field" into anything. You would only create a larger negative pressure field.)

 

[TomcatViP]

Did that phenomena affect fan-in-wing aircraft like the Ryan XV-5?

I think there is something with it. Not quite sure how much severly affected transition was for the Ryan design.
But here the fans segment the entire "wing" span in two points.

 

[Bill S]

You guys are enjoying the Verticraft design so much I will add these for your viewing pleasure.

 

[taildragger]

Did that phenomena affect fan-in-wing aircraft like the Ryan XV-5?

I think there is something with it. Not quite sure how much severly affected transition was for the Ryan design.
But here the fans segment the entire "wing" span in two points.

It can't be settled from an armchair but I'm not sure it would be a problem. There would be a low pressure area atop the fuselage wing in both vertical and horizontal flight, created by the fans and the airfoil respectively. In transitioning to forward flight, the fans would probably produce more lift initially just as a helicopter rotor does in forward flight. At some point you'd think that flow over the airfoil would disrupt flow through the fans, but how the transition would occur??
The transition to hover would seem more straightforward but might have to be performed in a descent.

 

[hesham]

From Vertiflite 1962,

a strange jet powered engines,maybe just a hypothetical design ?.

 

[yasotay]

Suspect it is just an artist design based on some of the flying things to promote Western Gear.

 

[hesham]

From University of Illinois at Urbana–Champaign project hummingbird 1961,

Grumman G-242.

 

[Bill S]

From Fairchild Report R351-001 M-351 Proposed Low Speed Control System Investigation For Tri-Service VTOL Assault Transport [NARA II].
"The Fairchild M-351 was a hypothetical VTOL transport design configured to meet the requirements of the Tri-Service VTOL Assault Transport airplane. "
"The actual proposal was to conduct a free-flight model program on a novel type of low speed control system, applicable to tilt wing VTOL aircraft configurations."

 

[Vahe Demirjian]

And may be it was Douglas Model-828/A;

Quite possibly so. This patent drawing shows the 1961 Douglas/Doak tilt-duct project, so it's perfectly consistent with it being either the Douglas D-828 or the D-829.
Alternately, it could also be this one:

This illustration can't be the D-828, because the tilt-duct machine in this picture has two ducted fans, and the D-828 had four General Electric T64s driving tilting ducted fans. The D-829 was a tilt-prop design with four T64s.

 

[METROLINER67]

If A-10 is "warthog", then what is this??

Since it's used for transport, "Hippopotamus"?

 

[RAP]

I pulled together some of the info and photos from the report Hesham noted above. I found this report at: https://archive.org/details/NASA_NTRS_Archive_20140008647