Why are UH-1N's so underpowered?

[mmx1]

I've been hearing a lot of talk about how underpowered the UH-1N is and how much crews are looking forward to the Yankee upgrade to restore the Huey to its former role as a true utility craft. One pilot told me that realistically it can only carry five personnel, crew included, and maintain a useful mission profile.

What puzzles me is how it came to be so underpowered. Clearly at some point it was capable of performing utility missions - in Vietnam the single engine Huey was the principal assault support and utility helicopter; and the Marines used them in a similar role some years back. How is it that they're now considered underpowered and can't utilize their full troop capacity?

Has additional gear compromised the lifting capacity of the Huey? Or is it simply that the expectations of speed and range have gone up, so the Huey is forced to carry a lighter load in order to keep up? Or has age simply deteriorated their performance?

 

[phrogpilot73]

Has additional gear compromised the lifting capacity of the Huey? Or is it simply that the expectations of speed and range have gone up, so the Huey is forced to carry a lighter load in order to keep up? Or has age simply deteriorated their performance?

A combination of factors leads to degraded performance. Armor, ASE gear, weapons systems, engine degradation, etc... all lead to degraded performance. The CH-46E suffers from some of the same problems, which is why they were able to rustle up money for -16A engines in order to regain some of the lost performance.

 

[hscs]

This happens to most helos -- as they age, more stuff is added on to the airframe. The block 1 -60S that weighs 17.4k with crew on takeoff and adding almost 5k in weight when you add additional weapons, armor, ASE, FLIR, and gas.

 

[Zilch]

"-16a?"

 

[phrogpilot73]

"-16a?"

When I hit the fleet, the CH-46E had the PMS (Power Mangement System) and the T58-GE-16 engines. All CH-46E's have been upgraded to the ECCS (Engine Condition Control System) and T58-GE-16A engine. Of course, as engines fail, they can replace the -16A's with -16's. So there's a mix, but eventually it will be all -16A's.

With the -16A's, what they've done is taken an old -16 and replaced the compressor, combustor and high-pressure turbine, made modifications to the power turbine and engine accessory package, and added a Titanium Nitride (TiN) coating process for the compressor blades, reducing blade erosion and improving engine time-on-wing. The idea is to increase time between engine changes and also to reclaim the lost power, and get the CH-46E back up to 1870 SHP per engine.

 

[FlyinSpy]

This happens to most helos -- as they age, more stuff is added on to the airframe.

There's an old saying, attributable to either Kelly Johnson or Ben Rich, that "an aircraft tends to gain a pound a day". As an airframe ages, folks are tempted to keep adding on new widgets, until 10 years later you're 3650 pounds heavier. (For the math challenged, that's a pound a day for 3650 days....). Most definitely a loose rule, but you can see weight growth in just about every platform out there. It would be interesting to compare the gross takeoff weight of the 1959 version of the UH-1 to today. The pound a day rule is probably a big overstatement there, but then again the airframe has been around a lot longer than most....

 

[e6bflyer]

...until 10 years later you're 3650 pounds heavier. (For the math challenged, that's a pound a day for 3650 days....).....

OK, Mr. Smartie pants, what about leap years?! Huh?!

 

[HueyCobra8151]

Supposedly the Iroquois will go from being our slowest helicopter to our fastest when the Yankee model comes out.

About time, sad sight to see Hueys so loaded up they can't even make it out of the valley at MCAS Pendleton without a few running starts.

 

[Pags]

Supposedly the Iroquois will go from being our slowest helicopter to our fastest when the Yankee model comes out.

About time, sad sight to see Hueys so loaded up they can't even make it out of the valley at MCAS Pendleton without a few running starts.

fastest until you have to open the doors

 

[HueyCobra8151]

Yeah I am sure there are all sorts of asterisks attached to that statement.

 

[phrogpilot73]

About time, sad sight to see Hueys so loaded up they can't even make it out of the valley at MCAS Pendleton without a few running starts.

What's sad are Phrog crews knowing that when being escorted by a Huey and they say they're sprinting forward, that they're really calling for knots...

 

[ChuckMK23]

When I hit the fleet, the CH-46E had the PMS (Power Mangement System) and the T58-GE-16 engines. All CH-46E's have been upgraded to the ECCS (Engine Condition Control System) and T58-GE-16A engine. Of course, as engines fail, they can replace the -16A's with -16's. So there's a mix, but eventually it will be all -16A's.

With the -16A's, what they've done is taken an old -16 and replaced the compressor, combustor and high-pressure turbine, made modifications to the power turbine and engine accessory package, and added a Titanium Nitride (TiN) coating process for the compressor blades, reducing blade erosion and improving engine time-on-wing. The idea is to increase time between engine changes and also to reclaim the lost power, and get the CH-46E back up to 1870 SHP per engine.

Trivia - the TiN process was invented by - and is now licensed from a Russian manufacturing company. NADEP calls these engines "gold striped"

What is a Phrog pilot to do without PMS and ECA's. No more drama of unexplained engine failures. Oh what to do!

 

[phrogpilot73]

Trivia - the TiN process was invented by - and is now licensed from a Russian manufacturing company. NADEP calls these engines "gold striped"

No idea, but if I had to go with a SWAG - it would be Mil?

What is a Phrog pilot to do without PMS and ECA's. No more drama of unexplained engine failures. Oh what to do!

You and I are going to disagree on this one. I've flown PMS/ECCS and -16s/-16As. I've had a sum total of 3 engine failures. All three were with ECCS and -16As. The elimination of Emergency Throttle on the ECCS is the worst decision NAVAIR ever made. I can no longer get to topping with the engine if I need to. But I can beep the engine down far enough to shut it down. Just my personal opinion (especially since my contract supports NAVAIR!)

 

[ChuckMK23]

No idea, but if I had to go with a SWAG - it would be Mil?


You and I are going to disagree on this one. I've flown PMS/ECCS and -16s/-16As. I've had a sum total of 3 engine failures. All three were with ECCS and -16As. The elimination of Emergency Throttle on the ECCS is the worst decision NAVAIR ever made. I can no longer get to topping with the engine if I need to. But I can beep the engine down far enough to shut it down. Just my personal opinion (especially since my contract supports NAVAIR!)

Oh man - I had no idea they got rid of ET (a big red button on the collective that allowed your beep switches to manually control the fuel metering valve on the fuel control! Be careful!!!). And the system won't let the motor deliver topping? Alright - that is BAD!

My experience with the old PMS - it was a bitch to set up during FCF's - the load balancing never worked great anyways - and all PMS did was prevent topping in my eyes. As HAC, I always briefed that PMS stayed off for all shipboard ops - and it was the PNF's job to roughly match the beeps.

I had a number of ECA and PMS engine issues - and even had PMS shutdown an engine on me inexplicably - blue water, single spot ship with no other platforms anywhere.

I was under the impression that the new engine control/condition system on the 16A's were "da bomb"! at least that's what Pee Wee Powers relayed to me before he took his squadron to Afghanistan..

So has it not worked out while deployed? WHat's the engine setup and topping checks during FCF like now?

 

[phrogpilot73]

(a big red button on the collective that allowed your beep switches to manually control the fuel metering valve on the fuel control! Be careful!!!) And the system won't let the motor deliver topping? Alright - that is BAD!

The big red button is still there... And it now activates "Manual Trim", which as far as I can tell is vodoo magic. Not like the ET where it no shit controlled the ETA... When you activate manual trim (which, oh-by-the-way is #1 step in single engine procedures now, apparently - it's THAT important), it allows you to control the beeps on the engine, but it's more like turning PMS off. You can't exceed the limits, no matter how much seat cushion you're sucking up. You CAN beep it down to shut the engine down though....

all PMS did was prevent topping in my eyes. As HAC, I always briefed that PMS stayed off for all shipboard ops - and it was the PNF's job to roughly match the beeps.

Never had a problem with PMS, maybe because it was on it's way out As a HAC (and even as a 2P), the guy not at the controls kept his thumb and forefinger firmly gripping the PMS switch during T/O (both shipboard and land). That's how we took care of it - switch off and you can hit topping!

I was under the impression that the new engine control/condition system on the 16A's were "da bomb"! at least that's what Pee Wee Powers relayed to me before he took his squadron to Afghanistan..

So has it not worked out while deployed? WHat's the engine setup and topping checks during FCF like now?

Can't talk to topping checks, because I was never an FCP. However, I will tell you that overall I think that the ECCS system is good, and while the -16As are a good theory, all three engine failures in Iraq were -16As. Am I biased? Maybe - the -16s never failed me...