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keesje
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Sikorsky, Boeing provide first look at SB>1 Defiant

Fri Jan 04, 2019 1:27 pm

Sikorsky, a Lockheed Martin company, and Boeing provided the first look at the SB>1 Defiant helicopter the companies have developed for the U.S. Army's Joint Multi-Role technology demonstrator program. The SB>1 Defiant is designed to fly at twice the speed and range of today's conventional helicopters and offers advanced agility and maneuverability.


Image

The main rotor technology has been in use over 40 years by Kamov, The push rotors ads a lot of structure, costs and ... speed.

:arrow: We are trying to create a dedicated helicopter VTOL forum for topics like this. Take a few second to support. Thnx!

https://www.airliners.net/forum/viewtopic.php?f=12&t=1385281
"Never mistake motion for action." Ernest Hemingway
 
tommy1808
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Fri Jan 04, 2019 3:02 pm

keesje wrote:
The main rotor technology has been in use over 40 years by Kamov, The push rotors ads a lot of structure, costs and ... speed.


That may just be why Airbus went the one rotor, two props route. The 2nd prop probably adds less weight than a 2nd main rotor.

Best regards
Thomas
This Singature is a safe space......
 
texl1649
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Joined: Thu Aug 02, 2007 5:38 am

Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Fri Jan 04, 2019 3:31 pm

The V280 just appears to be a much more elegant/lighter package than this, to me. It will be interesting to see how these ‘tech demonstrator’ aircraft evolve next. I also would like to catch a glimpse of what Boeing is touting as a ‘compound conversion’ for the AH-64’s. That sounds, well, interesting.

http://www.thedrive.com/the-war-zone/25 ... -prototype

I think AVX is still intent on competing, somehow, for a portion of the future procurement programs, and I’m partial to their designs/philosophy, but it would be great to see prototypes/actual aircraft being built.

https://www.avxaircraft.com/characteristics/
 
bunumuring
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sat Jan 05, 2019 12:43 pm

Hey guys,
The Defiant looks 'bulky' yet has a small fuselage.... It doesn't look quite 'right' to me with such a tall rotor mast.
I am very interested In how the V-280 and the SB>1 compare.
Cheers,
Bunumuring
I just wanna live while I'm alive!
 
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Nomadd
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sat Jan 05, 2019 3:09 pm

Wouldn't counter-rotating main props add quite a bit of speed even without a pusher by letting you run them at higher rpm without trailing edge stall being as much of a limit?
 
RJMAZ
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sun Jan 06, 2019 3:07 am

If this design gets selected it is a major step backwards.

There are so many advnantages with a tilt rotor with very few disadvantages.

During cruise you gain efficiency by using wings to produce lift. Much less thrust is then required to move it forward.

The SB1 still requires lift to be provided by the props which burns lots of fuel. It could never reach the top speed of a tilt rotor.

Tilt rotors can also do rolling takeoffs to increase payload/range.

The only downside to the tilt rotor is it requires a slightly higher thrust when hovering. This is due to the smaller rotor area giving a higher disc loading. It requires more power to push the same volume of air.
 
DarkKnight5
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Joined: Fri Apr 15, 2016 3:36 pm

Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sun Jan 06, 2019 7:08 am

RJMAZ wrote:
If this design gets selected it is a major step backwards.

There are so many advnantages with a tilt rotor with very few disadvantages.

During cruise you gain efficiency by using wings to produce lift. Much less thrust is then required to move it forward.

The SB1 still requires lift to be provided by the props which burns lots of fuel. It could never reach the top speed of a tilt rotor.

Tilt rotors can also do rolling takeoffs to increase payload/range.

The only downside to the tilt rotor is it requires a slightly higher thrust when hovering. This is due to the smaller rotor area giving a higher disc loading. It requires more power to push the same volume of air.


It could also be that the service is more interested in hovering and getting to the ground and back in the air faster than you can with a tilt rotor. A traditional helicopter is more agile up and down than tiltrotor.

The tiltrotors main advantage is in cruise, but a high cruise is not necessarily preferable to the agility on all missions.
 
Ozair
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sun Jan 06, 2019 8:14 am

DarkKnight5 wrote:
RJMAZ wrote:
If this design gets selected it is a major step backwards.

There are so many advnantages with a tilt rotor with very few disadvantages.

During cruise you gain efficiency by using wings to produce lift. Much less thrust is then required to move it forward.

The SB1 still requires lift to be provided by the props which burns lots of fuel. It could never reach the top speed of a tilt rotor.

Tilt rotors can also do rolling takeoffs to increase payload/range.

The only downside to the tilt rotor is it requires a slightly higher thrust when hovering. This is due to the smaller rotor area giving a higher disc loading. It requires more power to push the same volume of air.


It could also be that the service is more interested in hovering and getting to the ground and back in the air faster than you can with a tilt rotor. A traditional helicopter is more agile up and down than tiltrotor.

The tiltrotors main advantage is in cruise, but a high cruise is not necessarily preferable to the agility on all missions.

One other disadvantage based on feedback from the Middle East is the V-22, and you would expect other tilt-rotors, also have a higher incidence of brown out. The USMC have done a lot to overcome it and hopefully the next 30 years of US Military ops aren't in sandy locations but it would be a factor to consider.
 
bunumuring
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sun Jan 06, 2019 12:45 pm

Hey guys,
i see the benefits of both approaches to the requirements and appreciate RJMAZ and Ozair's opinions above. It will be fascinating to watch how this competition goes.
Cheers,
Bunumuring
I just wanna live while I'm alive!
 
bigjku
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Joined: Sat Feb 17, 2007 10:51 pm

Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sun Jan 06, 2019 7:53 pm

DarkKnight5 wrote:
RJMAZ wrote:
If this design gets selected it is a major step backwards.

There are so many advnantages with a tilt rotor with very few disadvantages.

During cruise you gain efficiency by using wings to produce lift. Much less thrust is then required to move it forward.

The SB1 still requires lift to be provided by the props which burns lots of fuel. It could never reach the top speed of a tilt rotor.

Tilt rotors can also do rolling takeoffs to increase payload/range.

The only downside to the tilt rotor is it requires a slightly higher thrust when hovering. This is due to the smaller rotor area giving a higher disc loading. It requires more power to push the same volume of air.


It could also be that the service is more interested in hovering and getting to the ground and back in the air faster than you can with a tilt rotor. A traditional helicopter is more agile up and down than tiltrotor.

The tiltrotors main advantage is in cruise, but a high cruise is not necessarily preferable to the agility on all missions.


Agree here. For example I would expect this configuration to lift more in a sling type situation.

Overall for aircraft that are supposed to be helicopters and work vertically I like this design better.
 
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GE9X
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Mon Jan 07, 2019 1:23 am

There is always this "debate" that pops back up as if tiltrotor and compound where an either/or situation. This is not a zero sum competition, although it is being framed as one. There is a case for having both a tiltrotor and a compound helicopter in the future, and this is very likely the path the Army and other services will take. Tiltrotors are great for speed but lack in nimbleness, while compound helicopters are good (not great) for speed and excellent for nimbleness. Tiltrotor hovering is less than ideal, as seen on the CV-22 and MV-22, and this limitation is simple physics, it can be mitigated but not entirely. Tiltrotors will be excellent at supporting longer range raids and logistics to FOBs including troop transfers, but not for most applied combat missions in any reasonable theater size. The attack platforms which will replace the Apache and Cobra/Viper down the road will almost certainly be compound and not tiltrotor because they need to be extremely nimble, quick up and down, turn on a dime, etc, which a tiltrotor cannot do well, especially not in hot, high, and sandy/dusty places. Utility platforms at a tactical level, including medevac/CSAR, will also probably have to be compound or conventional as well, for the same reasons of nimbleness. One of the reasons the Air Force rejected using the CV-22 as a primary CSAR platform is that although it is fast, which gets troops on target very quickly, once it gets on target it is much more of a "pig" so to speak. Massive downwash on rappelling, guaranteed brownout in dusty places, enormous LZ required to land or hover, and basically can't operate over rooftops or in constrained valleys and canyons, the list goes on and on. AFSOC Osprey operations continue, because it is useful to get people far and quick, but it's messy and some would say dangerous. The V-280 will obviously be a major improvement on the V-22 but the basic limitations of tiltrotors will still be an issue going forward.
 
sasd209
Posts: 391
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Mon Jan 07, 2019 3:02 am

GE9X wrote:
There is always this "debate" that pops back up as if tiltrotor and compound where an either/or situation. This is not a zero sum competition, although it is being framed as one. There is a case for having both a tiltrotor and a compound helicopter in the future, and this is very likely the path the Army and other services will take. Tiltrotors are great for speed but lack in nimbleness, while compound helicopters are good (not great) for speed and excellent for nimbleness. Tiltrotor hovering is less than ideal, as seen on the CV-22 and MV-22, and this limitation is simple physics, it can be mitigated but not entirely. Tiltrotors will be excellent at supporting longer range raids and logistics to FOBs including troop transfers, but not for most applied combat missions in any reasonable theater size. The attack platforms which will replace the Apache and Cobra/Viper down the road will almost certainly be compound and not tiltrotor because they need to be extremely nimble, quick up and down, turn on a dime, etc, which a tiltrotor cannot do well, especially not in hot, high, and sandy/dusty places. Utility platforms at a tactical level, including medevac/CSAR, will also probably have to be compound or conventional as well, for the same reasons of nimbleness. One of the reasons the Air Force rejected using the CV-22 as a primary CSAR platform is that although it is fast, which gets troops on target very quickly, once it gets on target it is much more of a "pig" so to speak. Massive downwash on rappelling, guaranteed brownout in dusty places, enormous LZ required to land or hover, and basically can't operate over rooftops or in constrained valleys and canyons, the list goes on and on. AFSOC Osprey operations continue, because it is useful to get people far and quick, but it's messy and some would say dangerous. The V-280 will obviously be a major improvement on the V-22 but the basic limitations of tiltrotors will still be an issue going forward.


That is one of the best posts I have seen in some time.... agree, well done and cheers!
 
426Shadow
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Wed Jan 09, 2019 1:34 am

Pick both, spread the wealth, problem solved.
Do it on three, One.....THREEEEEEE! Just got the nuts hangin out.
 
JayinKitsap
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Wed Jan 09, 2019 2:16 am

426Shadow wrote:
Pick both, spread the wealth, problem solved.


That allows the machine that is best for the task to be used. Novel Concept! :scratchchin:

I think they should do both, there are enough needed to cover the R&D of each. Then, there is also some bidding incentive, the best price but also performance can be judged. The total orders could be divided into 1/3 rd chuncks - tilt 1/3, compound 1/3, and the best bird could take as much as 1/3, or closer to balanced if both are good machines.
 
texl1649
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Wed Jan 09, 2019 3:20 am

The V-22 as the ‘prototypical’ tiltrotor isn’t fair to the platform though, as it had to be designed with rotors limited to lengths allowing it to be stored on ships, folded. Any sane design today wouldn’t rotate the engines, only the nacelles, and would also have much larger diameter rotors. This decreases brown out and vortex ring state alike, dramatically.

The USN and Marines insisted the V-22 fit aboard carriers, of course. Almost no USN aircraft are ever good at other missions/environments, because they’re absurdly limited to basically 1960’s (or before) conceptions of naval warfare. The F-35 is the exception based essentially on the fact that it’s got billions rolled into it’s software/communications/electronics suite for other variants.
 
bunumuring
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Joined: Wed Jan 15, 2014 2:56 pm

Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Wed Jan 09, 2019 9:37 am

JayinKitsap wrote:
426Shadow wrote:
Pick both, spread the wealth, problem solved.


That allows the machine that is best for the task to be used. Novel Concept! :scratchchin:

I think they should do both, there are enough needed to cover the R&D of each. Then, there is also some bidding incentive, the best price but also performance can be judged. The total orders could be divided into 1/3 rd chuncks - tilt 1/3, compound 1/3, and the best bird could take as much as 1/3, or closer to balanced if both are good machines.


Hey guys,
I love the idea... But would it work in the real world? It would definitely increase the cost of training, maintenance etc...
Cheers,
Bunumuring
I just wanna live while I'm alive!
 
426Shadow
Posts: 86
Joined: Tue Sep 11, 2007 8:13 am

Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Wed Jan 09, 2019 11:42 pm

bunumuring wrote:
JayinKitsap wrote:
426Shadow wrote:
Pick both, spread the wealth, problem solved.


That allows the machine that is best for the task to be used. Novel Concept! :scratchchin:

I think they should do both, there are enough needed to cover the R&D of each. Then, there is also some bidding incentive, the best price but also performance can be judged. The total orders could be divided into 1/3 rd chuncks - tilt 1/3, compound 1/3, and the best bird could take as much as 1/3, or closer to balanced if both are good machines.


Hey guys,
I love the idea... But would it work in the real world? It would definitely increase the cost of training, maintenance etc...
Cheers,
Bunumuring


Look at how many times up until now the different branches have demanded different machines and got them. Why not have one service demand heli's machines for different missions the same way there are different airplanes for different missions.
Do it on three, One.....THREEEEEEE! Just got the nuts hangin out.
 
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Slug71
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Re: Sikorsky, Boeing provide first look at SB>1 Defiant

Sun Jan 20, 2019 2:24 am

Just such a dated looking hull.

Kinda reminds me of a Aloutte III.
Or Aloutte III crossed with a UH-60.

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