• Please take a moment and update your account profile. If you have an updated account profile with basic information on why you are on Air Warriors it will help other people respond to your posts. How do you update your profile you ask?

    Go here:

    Edit Account Details and Profile

New Bell 525 reporting 200 knots?

Randy Daytona

Randy Daytona

Cold War Relic
pilot
Super Moderator
If this is the case, wow. It does not mention if this is level flight or a powered descent. This is Bell's first fully articulated rotor system and first fly by wire helicopter if I am not mistaken.

Bell Helicopter has now taken its developmental 525 super-medium twin to a speed of above 200kt (370km/h) as it prepares for the arrival of the programme’s third flight-test vehicle.

https://www.flightglobal.com/news/articles/bell-speeds-525-prototype-to-200kt-424394/

https://www.flightglobal.com/news/a...s-third-525-relentless-takes-flight-i-424645/

getasset.aspx


getasset.aspx
 
The office I work in is the responsible certifying authority for the FAA in certifying the Bell 525. It is most definitely an interesting program to be involved with. I believe the 200 kt figure is in level flight. It is most likely one of Bell's top priorities as they've relied heavily on legacy programs in the past.
 
Dumb fixed-wing guy question. The absolute top-end speed of a TACAIR jet isn't a be-all and end-all performance metric, thanks to Col Boyd and E-M theory. I know helos are often valued by how much they can lift rather than how fast they can go unloaded. And that they have all the funky aero and physics issues incumbent in the spinny thing on top that limits their top end speed. What practical purpose is Bell designing for that happens to show up in a 200 knot helo?
 
It may just be a demonstration that the aircraft is safe up to its VNE.

Short answer: It's a good sales stat, like horsepower for cars.

Long answer: All the services are interested in helos that can get where they're going more quickly. One of the biggest driving factors for military and civilian helos is the "golden hour," a SAR concept that says a patient is much more likely to live if you can get them to a medical facility within 60 mins of the injury. But response time can also be applied to CAS/SCAR, PR, and ASW.

Dumb rotary-wing question: what is the typical relation (in percent) between Vrange and Vh for a fighter? For the helos I've flown, Vrange tends to be pretty close to Vh, and is limited by Vh for higher gross weights/DAs. Example: for a typical SH-60F at SLS conditions, Vrange is 90% of Vh. Anyway, civilians like to conserve fuel, so a higher Vrange would mean quicker times to/from the oil rig/hospital without additional fuel costs.
 
IKE said:
It may just be a demonstration that the aircraft is safe up to its VNE.

Short answer: It's a good sales stat, like horsepower for cars.

Long answer: All the services are interested in helos that can get where they're going more quickly. One of the biggest driving factors for military and civilian helos is the "golden hour," a SAR concept that says a patient is much more likely to live if you can get them to a medical facility within 60 mins of the injury. But response time can also be applied to CAS/SCAR, PR, and ASW.

Dumb rotary-wing question: what is the typical relation (in percent) between Vrange and Vh for a fighter? For the helos I've flown, Vrange tends to be pretty close to Vh, and is limited by Vh for higher gross weights/DAs. Example: for a typical SH-60F at SLS conditions, Vrange is 90% of Vh. Anyway, civilians like to conserve fuel, so a higher Vrange would mean quicker times to/from the oil rig/hospital without additional fuel costs.
Click to expand...
Faster from A to B.

Get in more runs of whatever it is you're doing in a day.
 
nittany03 said:
Dumb fixed-wing guy question. The absolute top-end speed of a TACAIR jet isn't a be-all and end-all performance metric, thanks to Col Boyd and E-M theory. I know helos are often valued by how much they can lift rather than how fast they can go unloaded. And that they have all the funky aero and physics issues incumbent in the spinny thing on top that limits their top end speed. What practical purpose is Bell designing for that happens to show up in a 200 knot helo?
Click to expand...

The top end speed of a cargo airplane is a more appropriate analogy. As said above, it is speed from A to B - and the greater the speed, the greater the range. As the most important limitation on top speed is not drag but rather retreating blade stall, conventional helicopters are normally limited to below 200 knots (140 - 170 is normal). If you want to go substantially faster, there are 3 different ways:

1) Tilt rotor (MV-22, AW-609, V-280) - fastest, longest range but less hover performance (the ability to land at high altitude), less payload, and by far the most complicated / expensive. Not too many militaries or civilian operators can afford it.
images
images
images



2) Advancing blade concept (ABC) (contra-rotating main rotors with a pusher propeller). Sikorsky X-2 and Sikorsky S-97 - substantially faster than conventional helicopters but less than a tilt-rotor. Solid hover performance. Contra-rotating main rotors would seem to limit the upper end of size as the rotors have to be close together to limit drag but far enough apart for them to flap without hitting each other. Sikorsky seems to think they can make the rotor system stiff enough to get up to 30,000 lbs. I would bet this would be the future.

images


3) Compound helicopter (main rotor + wings + pusher or tractor propellers) - Eurocopter X3, Lockheed AH-56 Comanche - roughly same performance and capabilities as the ABC. Less complicated than a ABC.

images


All 3 are competing for the FVL - Future Vertical Lift - which is due out in 10 to 15 years.

I was asking a similar question earlier in the Osprey thread. Perhaps the way of matching a tilt-rotors range is to use a bigger helicopter - more lift thus more payload (fuel). The MH-53E with 22,000 of gas normally (about 7 hours) and the MH-47G with double the fuel of a regular Chinook seem to have close to the range of an Opsrey - the tradeoff is what the the helicopters lack in speed they can make up with a bigger payload downrange.
 
Yeah the practical use has been a big question mark in the office, Bell likes to take a flashy marketing approach. The FBW controls in the cockpit are for the most part derived from the V-22. EASA and the Transport Canada dudes/and girl tore into the aircraft design/methodology/what have you all last week. The paperwork side is a work in progress.
 
Randy Daytona said:
I was asking a similar question earlier in the Osprey thread. Perhaps the way of matching a tilt-rotors range is to use a bigger helicopter - more lift thus more payload (fuel). The MH-53E with 22,000 of gas normally (about 7 hours) and the MH-47G with double the fuel of a regular Chinook seem to have close to the range of an Opsrey - the tradeoff is what the the helicopters lack in speed they can make up with a bigger payload downrange.
Click to expand...

What would the max range of either the MH-53E or MH-47G be with about 6,000 lbs of cargo (or pick whatever amount of cargo you want, it's arbitrary for this discussion)? Likewise, what is the time difference for conducting multiple, consecutive logistics missions? I don't know, but I bet helicopters will lose out to the MV-22 over a single day's worth of operations.
 
kmac said:
What would the max range of either the MH-53E or MH-47G be with about 6,000 lbs of cargo (or pick whatever amount of cargo you want, it's arbitrary for this discussion)? Likewise, what is the time difference for conducting multiple, consecutive logistics missions? I don't know, but I bet helicopters will lose out to the MV-22 over a single day's worth of operations.
Click to expand...

I will take that bet. Lot depends on where you are operating from. If you are operating from a high altitude LZ or from the back of a ship that does not allow a running start. A V-22 would be operating at a distinct disadvantage in these situations. Once I know how much cargo a V-22 can take off with at a max full load, it will be easier to make a judgment.
 
Plus you have to consider the time it takes to make multiple runs. A MH-53E is obviously slower than an MV-22. Can it carry more on a single run, of course? But does the ability to carry more translate into more cargo being carried over time?
 
kmac said:
Plus you have to consider the time it takes to make multiple runs. A MH-53E is obviously slower than an MV-22. Can it carry more on a single run, of course? But does the ability to carry more translate into more cargo being carried over time?
Click to expand...

I think I had this question on the SAT. If a car travelling 60 mph starts at Pt A.....

Will wait for a V-22 guy to tell us what they can carry at max fuel; both from a runway and also taking off vertically.
 
kmac said:
What would the max range of either the MH-53E or MH-47G be with about 6,000 lbs of cargo (or pick whatever amount of cargo you want, it's arbitrary for this discussion)? Likewise, what is the time difference for conducting multiple, consecutive logistics missions? I don't know, but I bet helicopters will lose out to the MV-22 over a single day's worth of operations.
Click to expand...
Rule of thumb for the Big Iron is 30K of fuel and cargo (with 22K max bag). Plan for about 4000 lbs per hour, be on deck with 2k. cruise at 135ish true
 
News update from the office of Ron Burgundy's DFW branch:

The speed reported above 200 kts was in a shallow dive. Bell is still working to determine VNE for the aircraft.
 
Randy Daytona said:
I think I had this question on the SAT. If a car travelling 60 mph starts at Pt A.....

Will wait for a V-22 guy to tell us what they can carry at max fuel; both from a runway and also taking off vertically.
Click to expand...

Well, if we go by what the good blue book (or publicly available info on wikipedia, your choice) says... say a basic empty weight of 34K, add 1K for crew, and 500lbs for kit and tools. 11.5K for gas makes for a mission weight of 47K.

A max VTOL/HOGE MTOW limit of 52.6K and a STO MTOW limit of 57K - or 60.5K for "self deployment" - calls for 5.6K cargo in VTOL and 10K in STO with full bags and crew. That self deployable 60.5K limit allows for 13.5K. Not a lot by comparison to a -47 or -53, but those guys also don't take off at 54K and do 300-320 ground at FL190 from CA to TX on one fill up. I've never gone above that 54K, but the controls were pretty mushy taking off in west Texas...
 
You must log in or register to reply here.
Back
Top