I would suggest Bell-Boeing have no bragging rights to on-time delivery of Tilt Rotors.

What matters is how long the Customer is willing to wait and what priority it places on timely delivery of the machines..

Keeping Promises and Full Transparency
 

While I respect and admire the engineering and manufacturing team work working on the SB-1, the top executives at both Sikorsky and Boeing have conducted themselves poorly.

The facts are as follows;

Sikorsky/Lockheed and Boeing are the two largest defense contractors in the world. Bell/Textron is ranked about number 11 in the US.

The combined man power and financial assets of Sikorsky/Lockheed and Boeing are an order of magnitude greater than Bell/Textron.

Bell prior to FVL contract signing requested approximately eight additional months to achieve first flight. The extension was rejected based on Sikorsky and Boeing’s promises that they could meet the contract date of first flight in fall of 2017.

While the SB-1 rotor blades have been highlighted as the cause of the program delays, it does not take great effort to realize that based on late design reviews and delivery of major assemblies the entire program has been running a year behind schedule.

Bell has been transparent with the V-280 progress throughout the program. The SB-1 has been shrouded in secrecy except for when missing a milestone become obvious to the public.

Which aircraft is best still needs to be determined. But as far as keeping promises and transparency, Bell deserves to brag.

This is actually a pretty salient point, as Boeing themselves said that the iron bird has only been run twice to date which means without blades. If the blades truly are all they were waiting on, its hard to imagine that completed machine just sitting idle for 12 months.

Based on literally the only photo Boeing (probably inadvertently) released to date, I think the fuselage shape is what they have been showing in the newer CG videos starting from mid 2017.

https://pbs.twimg.com/media/C0D6b0ZWIAEk4cH.jpg

Since SB1 uses AFP, then that likely means all unidirectional tape material. One thing to consider is the damage tolerance capability of a high strain, ultra-stiff rotor blade constructed entirely of high modulus or UHM carbon tape. Even with modern toughened resin systems, it would be very interesting to see failure modes from typical ballistic threats or bird strikes

HI

At the very start of my Career I worked at Westlands at Yeovil on composites development.
We built a prototype tailboom for the scout from all Unidirectional High Modulus Carbon fibre ( there was not any woven product available in the mid 70's).
I witnessed the destructive test and I will never forget the load crack when it failed , to call it an explosive failure was an understatement.There were bits of tailboom all over the hangar. If I am not mistaken it exceeded design load by quite a factor .
I would suspect that the machine laid tape would be interleaved with woven fabric on any new blade , especially at the root .

Neil

Sounds like matrix failure of early epoxy non-toughened resins! I've heard a lot of stories like this from that era. Nowadays, the usage of elastomer toughened resin systems makes a matrix failure like that a bit less dramatic.

There is off-axis-laid tape in the design of the similar but smaller S-97 and X2 blades to create the required torsional stiffness, for example, but it is all still unidirectional tape with no fabric.

If you were using AFP to fabricate a SB1 blade, then the addition of broadgood fabric plies would negate the advantages of using an automated tape laying system as you would have to repeatedly stop the process. I imagine the additional bulk of fabric with the weft fibers could also cause overall weight challenges, since the warp direction is inherently softer from being woven and would require more plies to achieve the same stiffness.

Based on the patent applications for V280 blades, they appear to be made entirely of fabric material, though the design requirements of a proprotor are entirely different. Hopefully the SB1 blade patent shows up soon so we can see whats going on inside!

It’s Official
 

How is that crow tasting, Van Buiten?

So, first flight December 45th then. Sikorsky standard work!

Not much of a Christmas break
 

No. December 380th, 2017.

... and Sikorsky/Boeing have been a year behind Bell for years on the JMR project. They're just now showing photos of SB>1 on the tarmac.

https://cimg1.ibsrv.net/gimg/pprune....3b5904a76.jpeg


SB>1 photo, no hub fairings

Temporary Main Landings Gear?
 

Temporary Main Landings Gear?
 

Perhaps only a dolly for towing?

Look at the tailwheel housing (dorsal fin??)and the rear pusher prop proximity to the ground, wow. With my untrained eye any nose high attitude on touchdown (running landing, off level landing) and there's gonna be a nasty surprise for the crew up front. But damn, what a sexy looking beast !

Lockheed provided a better view of the back in the press kit, too...

https://cimg9.ibsrv.net/gimg/pprune....1c9271721.jpeg

The landing gear look real enough to me, but they clearly don't have the complex articulation of a AW609 or S-97... having a wide fuselage makes the gear simpler.

There isn't a need for significant cyclic flare, nose up landings in an X-2 type aircraft. Pilots can command a level body descent and deceleration using reverse thrust on the prop... and what a prop on the rear of this thing!