John,

Interesting observations on AAH. I knew one of the folks who was on the evaluation committee (this was about 15 years afterward), and he told me that when they first set down to evaluate the proposals, one thing they all agreed was that, "We are Not going to select 'Son of Cheyenne'". So, Lockheed had two strikes from the start. I also think that because Sikorsky was able to develop the S-67, which came close to matching AH-56's performance for a fraction of the R&D cost that this embarassed Army leadership and so Sikorsky had two strikes against it as well.

Drift
 

We're getting away from the point of this thread, so let me respond re the pre-AAH flying via PM.

Thanks,
John

Savoia,

XC-142 was really a Tilt-Wing rather than a Tilt-Rotor. While it was tested extensively and advanced concepts were proposed, it didn't go very far for a few reasons.

For one thing, in vertical mode, you were essentially pushing the largest airbrake in the world through the air, meaning less efficiency During transition, you're flying with a partially stalled wing and rotors that aren't at maximum efficiency, which limits the kinds of maneuvers you can do during that phase. Also, until transition is fairly far along, you're not getting much benefit from the wing. There's also a pretty high disc loading, which can lead to the autorotational characteristics of a brick. And, of course a tilting wing is heavy and complex.

Bell's concept stems from the realization that you don't really need to tilt the whole wing, just the rotors. The wing starts generating lift as soon as there is any forward motion, transition either way does not impose any extra maneuvering limitations, the whole thing weighs less, etc.

For JMR, the proof will be in the pudding...

Sans anhedral.....will try and dig them out.his schemes were more airliner orientated and much later than his autogiro days.
Also I was discounting the tilt wing which is very different.the Doak is close though.

CC: Thanks for your responses.

Do you have any thoughts on the 1958 Doak VZ-4 concept which used rotating ducted fans?

Rotating ducted fans, while they make for great movie props (think avatar), however the ring is a huge detriment in edgewise flight.

You might have noticed (based upon the pictures) that sometime over the course of a couple years of top secret flight testing, AgustaWestland removed them from their Project Zero machine.

Looks like they may not have anticipated the aerodynamic behavior and had to learn the old fashioned way.

Savioa:

The VZ-4 was tested for a year at Edwards AFB, then given to NASA in 1959. They did some tests, found some undesirable flight characteristics which may have been correctable with technology that would have been invented in years to come. It never did demonstrate its promised performance, I believe. Douglas liked the concept and bought the rights, and proposed an improved version to the US Army in 1961, but there was little interest. The company that seemed to go furthest with the concept was, ironically, Bell with their X-22.

http://www.kamov.net/wp-content/uplo...2-Aircraft.jpg

Since they were also flying their XV-3 at the time, they could compare the two technologies and decided that Tilt-Rotor had more promise and practicality. Since then no one seems to have pursued the concept.

The VZ-4 is on display at the U.S. Army Transportation Museum located at Fort Eustis, Virginia. The X-22 is said to be going on display at the Niagra Aerospace Museum in New York, opening in May, and the XV-3 is at the Air Force Museum at Dayton, Ohio

Here's an earlier Bell concept drawing of what would evolve into the V-280.

http://www.aviationweek.com/Portals/...Bell%20JMR.JPG

Belll V280 mock up HAI 2016
 

Last month, attended Heli Expo 2016 and here are my photos of the mock up

http://i57.photobucket.com/albums/g2...pszrbqqfra.jpg

http://i57.photobucket.com/albums/g2...pswdwdrvcx.jpg

http://i57.photobucket.com/albums/g2...ps6dnt8vin.jpg

http://i57.photobucket.com/albums/g2...psju8uunux.jpg

http://i57.photobucket.com/albums/g2...pso9ujw1ze.jpg

http://i57.photobucket.com/albums/g2...psgve4ub8l.jpg

http://i57.photobucket.com/albums/g2...psnsevb1rj.jpg

What do you call that glass cockpit? It looks a metre in width! Assuming it can display a view from a fixed forward facing camera, it looks like it would create a virtual reality, albeit a "through the window effect" rather than a first person pic as you get with VR goggles

Very interesting. What do you think if additional cameras were used and the screen was extended so it wrapped around the cabin, giving a 180 degree "view" of what is otherwise obscured? A 4x4 car manufacture is working on such a idea so the driver can "see" through the dashboard to view what is directly in front of the wheels.


Mickjoebill

The Bell V-280 JMR-TD seems to be coming along nicely from the pictures shown here:

http://aviationweek.com/site-files/a...te-Textron.jpg

The quality of the airframe shown in the pictures seems much better than what you would normally expect in a prototype.

Anyone know the intended cabin dimensions or at least its height?

It appears that they changed their minds form the original concept regarding where to put the main landing gear. The artist's conception from a few years ago had a tricycle gear footprint (like that of a CH-53).

Based on the mock-up displayed at AUSA, it appears to be a nice round set of numbers:

• Length: 15.0 ft
• Width: 8.0 ft
• Height: 5.0 ft
• Volume: 600 cu ft

For comparison's sake, the UH-60 Black Hawk's cabin dimensions are:

• Length: 12.6 ft
• Width: 7.0 ft (6.0 ft @ floor level)
• Height: 4.5 ft (max)
• Volume: 396 cu ft

While the CH-47 Chinook's figures are:

• Length: 30.5 ft
• Width: 7.5 ft
• Height: 6.5 ft
• Volume: 1486 cu ft

I/C

Thank you :ok:

I always considered cabin height to be a major issue with the Blackhawk family. Of course it was due to C-130 transportability requirements but that always seemed to be rather irrelevant.
The V280 mockup appears a bit cramped in that regard, probably due to the wing immediately above the sliding doors. Would be a bad start since stuffing a FVL Medium into a Hercules probably won't be required anymore.

At least 5 ft will be an improvement.

C-130 Requirement
 

Too true, Praet:

The Army requirements for the UTTAS were perhaps 95-99% right on target and to some extent prescient, but not here. To my knowledge, the only C-130 usage was during the fly-off competition with Boeing, just to ensure compliance.

https://theaviationist.com/2017/08/3...aft-prototype/

https://farm5.staticflickr.com/4408/...d29a63a8_b.jpg

better side view pic here: http://deepbluehorizon.********.com/...sts-begin.html

edit: this site's filters do not allow you to use the term "b l o g s p o t" even in links. laughable.

Good work by Bell. The effort involved just to construct that test stand was more than people realize. Hope the inlet airflow to those T64 engines is OK.

Begs the Question....
 

Will if no one else is going to ask the obvious question...

Any updates on the SB>1 Defiant progress?