206B3 with a C20R conversion

[Black Bear]

Can someone please talk about the 206B3 with this conversion? I'm interested in what the conversion entails, performance(is it suitable for high altitude ops in Colorado), reliability and any issues it has been known to have. Would it be worth consideration over a L1 or3 with the C30P?

[Flying Pig]

I flew a C20R in a 500E. The engine came back from Rolls Royce at 560SHP. Flew routinely in the Sierra. With the Aero Filters or FDC filters temping out is not an issue.

 

Calling Rolls in Oakland would be a great place to start. Engine coking was probably the biggest issue but Rolls has a fix for that issue.

 

I know you asked about a Bell, but figured it was better than nothing. if i recall I think the conversion is to the compressor section but dont know what parts. Im flying a 58 now with a C20B and Im living life in slow motion!

[helipilotm]

Can someone please talk about the 206B3 with this conversion? I'm interested in what the conversion entails, performance(is it suitable for high altitude ops in Colorado), reliability and any issues it has been known to have. Would it be worth consideration over a L1 or3 with the C30P?

First off what altitude and what weight are you at? Second what are you going to be doing?

 

I will tell you my experiences with the C20R haven't been that great. It does give you a little more power but it has its problems. The C20R is a replica of the C28 which was in the original L1's. problem children is the only thing I have to say. There's a reason you don't see them anymore. If your gonna be above 7000' in the summer with more than one passenger I would look at an L1 with the C30P conversion or an actual L3. My humble opinion

[Whistlerpilot]

I happen to be flying a Longranger with the C20R on this and my previous rotation. It gets good fuel economy that's the positive. On the last shift it started making metal and had to have the accessory gear box rebuilt as one of the bearings was going. I was told it was likely because it had been over-torqued previously. Then it had lots of start problems at different altitudes, with hung starts or hot starts depending on temp and alt. I way prefer the C30P and the modulated start.

 

Your question was about the C20R in a 206B model. The transmission in the 206B is limited to 317 hp anyway so you don't get the benefit of the extra hp from the C20R unless it's in a 206L with the beefier transmission.

 

Other than those complaints I like the Longranger with the C20R, it's lighter than an L3 and does almost the same mission but burns less fuel. Contrary to others opinions I like long-lining from it. Waiting to get back in the Astar next shift!

[helipilotm]

I happen to be flying a Longranger with the C20R on this and my previous rotation. It gets good fuel economy that's the positive. On the last shift it started making metal and had to have the accessory gear box rebuilt as one of the bearings was going. I was told it was likely because it had been over-torqued previously. Then it had lots of start problems at different altitudes, with hung starts or hot starts depending on temp and alt. I way prefer the C30P and the modulated start

Exactly what I was saying. They really are a pain in the rear. The two that I have flown had the exact problems your referring too. The second one started making metal rebuilt the gearbox, happened less than 50 hours later. They finally figured out it was the #1 bearing in the gas producer and the bearing cage from the compressor. They decided to swap it out for the C20J. Shortly after the other jet ranger started having the same issues. They replaced it before any other problems could come up. They had three L1's with the C28 in previous years with the same problem.

 

That's interesting, I've never heard of a C20 in a long ranger. I have a hard time believing a C20 can keep up with a C30. Not saying I don't believe you, crazier things have worked before.

[Mikemv]

206L LongRanger I - One 315kW (420shp) Allison 250C20B turboshaft driving a two blade main rotor and two blade tail rotor.

 

206L1 LongRanger II - One 375kW (500shp) Allison 250C28B.

 

206L3 LongRanger III & 206L4 LongRanger IV - One 485kW (650shp) Allison 250C30P.

 

 

Some of the earlier C20 versions have axial compressor stages mounted on the HP shaft to supercharge a relatively low pressure ratio centrifugal compressor. The -C20R is typical, pulling an overall pressure ratio of 8.0:1, at an airflow of 4.0 lb/s (1.8 kg/s), with a power output, at the shaft, of 450 hp (340 kW).

 

 

• Bell 206A - Initial production version, powered by an Allison 250-C18 turboshaft engine. FAA-certified in 1966. Selected as the OH-58A Kiowa in 1968.
  • Agusta-Bell 206A - License-built in Italy
• Bell 206A-1 - OH-58A aircraft that are reverse-modified for FAA civil certification.^[19]
• Agusta-Bell 206A-1 - License-built in Italy
• Bell 206B - Upgraded Allison 250-C20 engine.^[20]
  • Agusta-Bell 206B - License-built in Italy
• Bell 206B-2 - Bell 206B models upgraded with Bell 206B-3 improvements.^[20]
• Bell 206B-3 - Upgraded Allison 250-C20J engine and added 2 inches (51 mm) to tail rotor diameter for yaw control.^[20]
• Bell 206L LongRanger - Stretched, seven seat configuration, powered by an Allison 250-C20B turboshaft engine.
  • Agusta-Bell 206L LongRanger — License-built in Italy
• Bell 206L-1 LongRanger II - Higher-powered version, powered by an Allison 250-C28 turboshaft engine.
  • Agusta-Bell 206L-1 - License-built in Italy.
• Bell 206L-1+ LongRanger - Bell modifications, including 250-C30P engine, to upgrade aircraft to 206L-4 configuration.
• Bell 206L-3 LongRanger III - Powered by an Allison 250-C30P turboshaft engine.
  • Agusta-Bell 206L-3 - License-built in Italy.
• Bell 206L-3+ LongRanger - Bell modifications to upgrade aircraft to 206L-4 configuration.
• Bell 206L-4 LongRanger IV - Improved version, 250-C30P engine and transmission upgrade.

Edited August 10, 2013 by Mikemv

[Mikemv]

The C20R engine is based on the proven design of the C20B/J engine. This engine features an advanced compres- sor with two less stages than the C20B, yet delivers a higher pressure ratio.

The engine is available as an option on the Bell Helicopter Textron 206B III and the MD Helicopter MD 500E for improved hot/high performance.

Additional improvements include an enhanced power turbine that provides up to a FIVE percent increase in power (420hp increase to 450hp) and a two percent reduction in specific fuel consumption. Gearbox lip-seals and shaft journals have

also been improved to help reduce oil consumption.

A C20R does not produce 560hp output.

[Gomer Pylot]

I used to fly the straight 206L in the Gulf. It was a good aircraft, and would actually outrun the L1, because of the float configuration. The only problem with it was that the C20 didn't produce enough power, and would temp out when it was hot and you had a max gross load, which was almost all the time. The solution was to add a water/alcohol injection system, with a tank in the baggage compartment pressurized by the engine, with lines running to the engine intake. A switch on the collective activated the injection system, and on takeoff if the TOT was about to exceed the redline, you hit the switch and it injected a water/alcohol mixture into the intake, which cooled the TOT by a good bit, and let you finish the takeoff. You had about 1 minute of mixture in the tank, and that usually had to get you through the day, unless you could get back to the beach for a refill. It usually only took a few seconds of injection to get off the ground or platform and flying. I recall once when maintenance screwed up and filled a tank with pure alcohol, no water. The unlucky pilot got a huge power boost, but the TOT pegged, and his flight ended quickly. I don't recall the exact mixture, but it was several parts water to one part alcohol.

 

In cruise, the C20 did well in the L, and fuel consumption was about the same as in a 206B. AFAIK, all the straight L models were converted to L1's in the mid to late 80's. The C20 just wasn't enough engine for the airframe. The C28 had plenty of power at sea level, but maintenance problems caused most, if not all, L airframes to be converted to the C30, which burns a lot of fuel, but at least is reliable. It just loafs along at lower altitudes, never being pushed at all, capable of producing far more power than the transmission can use.

[Flying Pig]

 

A C20R does not produce 560hp output.

 

Crap.... thats what I get for not proof reading... 460. That was from an engine run test at Rolls Oakland.

[Mikemv]

FP,

 

I hate when I forget to proof read, but even 460hp only means that the engine meets/exceeds minimum specifications and validates the performance charts.

 

The aircraft is still Q (psi) limited by the transmission.

 

It is good knowing you have a strong engine to rely on.

 

That is why we run/record power assurance data.

 

Mike

[Flying Pig]

Yeah... that was just on the engine test stand at Rolls. But good knowing it had some juice.

[Gomer Pylot]

At sea level, the B3, like the L3, will produce more power than the transmission can accept, thus they are torque limited. The advantage of having an engine that produces much more power than the transmission is rated for is that it will keep producing enough power to high altitudes. The disadvantage is that it uses more fuel, and thus has less range and endurance. In aircraft design, everything is a compromise of some sort. Models that have good performance at high altitude tend to be gas hogs at sea level. The designer has to decide what factors are more important, and not everyone will agree with his choices. And "the designer" is really the corporation in most cases, not one individual.

Edited August 10, 2013 by Gomer Pylot

[Black Bear]

Thanks for all the great responses. If you were going to fly tours, heli fishing, camping, hiking etc., from a base at 8500 MSL, up to 11000, what would be your choice of A/c?

[helipilotm]

Thanks for all the great responses. If you were going to fly tours, heli fishing, camping, hiking etc., from a base at 8500 MSL, up to 11000, what would be your choice of A/c?

Hahaha if you think you can do any of that out of a 206B you obviously need to do some homework. If its just you and 25 gallons of gas you might be ok. Astar B3 would be my number one choice after that 407 or L4 with the high altitude t/r. 206B's, Enstrom's don't belong at 11,000' in the summertime! Don't even attempt it or you will kill yourself and others!

[aeroscout]

Interesting topic. Thanks to all.

[Black Bear]

I'm not shopping for A/c here. A friend of mine is considering taking over a fishing guide operation, and he, knowing I am a pilot wanted to know what I thought. I haven't given the subject much, if any consideration, but it got me interested enough to start some conversation here. I told him that there is better opportunity for all that he seeks in his business idea at lower elevations than 11000. If you aren't fit enough to make it there without a helicopter, you really have no business being there in the first place. Especially considering that most of the clients that would use this service are from lower elevations without proper acclamation to the altitude. I told him that taking an over weight, out of shape business man from Texas above timberline and dropping him off for an activity that involves some physical exertion is just wreckless. So, realistically, the consideration here would be more like 8500 to 10000'. I also told him that there is better fishing in Alaska than there is here in Colorado.