Turbine Time JetRanger II Ferry

[Falko]

Your are correct about the possible damage of an turbine/piston engine during startup but as you know, the 206 jet ranger start up's are easy and don't require you modulate the tot"206L models"

 

hit the starter, wait for 12-15% N1. I personally wait for 15% and Roll the throttle to idle and release the starter at 58% percent gen on and done you are. Unles the fuel control unit is scewed up or you have a weak battery, you shouldn't expect any issues when your rides long handles the start.

 

Maybe iAm too relaxed by at some point your student will have to start a turbine so why not let him do it as soon as he has the chance.

[aeroscout]

It's important to note battery voltage before start to be above 24v. If not, then there is a much higher possibility of a hot start. It's important to note TOT before start, and ensure it gets driven below 150 or less before lightoff. I always start the clock, coincident with hitting the starter. I also note the voltage drop, too much voltage drop can be a signal to warn of hot start. I always let N1 peak and stabilize before lightoff, ensuring the coldest start. I reference the clock when introducing fuel to observe 10 second limit. Finger positioning is important when rolling on throttle, one securely on starter, one securely on idle release. Blades turning by 25%, 58% achieved, starter disengaged by one minute. There is a lot to look at, and a lot to go wrong. I would much rather explain some starts, and demo a couple, and be confident the operator has a good understanding before letting them have their first solo start.

[helonorth]

You will immediately know whether it's going to start just by the sound of it. You really don't want it to be a cooler start because it's starts too slow. Light it off where ever the book says. I have never heard of letting the N1 wind up until it peaks and "stabilizes"(?) Your just running down your battery. Really not a lot a lot to look at, not a lot to go wrong. I have not seen many 206's with a volt meter. Don't over complicate it.

Edited December 22, 2011 by helonorth

[aeroscout]

I also didn't emphasize enough the importance of locking on to TOT from lightoff until peak TOT, and TOT receding, with the other instruments in peripheral vision. I disagree with your assessment of not wanting the coolest possible start. Cooler starts will ensure the longest engine life. There will be added load on the battery achieving peak N1, but not by much, and to me it's worth it. If you have never heard of peak N1 prior to lightoff I can only conclude you haven't been around turbines too long. No offense.

[SBuzzkill]

I've only got a couple hundred hours in turbines so take my opinion with a grain of salt, but it is my understanding that there is a sweet spot you want your TOT to be during start ups, not too cool or too hot. Supposedly this temperature range allows for the best expansion rate to occur on the parts inside the engine, decreasing wear. Also, while I have personally seen one person peak the N1, our operators manual says to open the throttle at the appropriate N1 for the temperature and every single instructor I have flown with other than that one person has done it that way. I believe N1 peaking is an outdated procedure.

Edited December 22, 2011 by SBuzzkill

[Pohi]

I know it might be apples and oranges, but the RFM for the L4 I fly recommends TOT between 716 and 826, less than 40 sec start. Basically in/above the yellow.

 

It says starts below 716 and greater than 40 sec may be detrimental to turbine components.

 

This may differ from the B model, but I was taught a fast hot start is better than a cool one.

[gary-mike]

Turbine engine start proceedures are set to maximize component life, and to minimize the occurance of emergency situations on start up. I recomend following the proceedures outlined in the POH. The engineers have done much more valid research than joe shmo that thinks he has a better way. That being said, the proceedures are made to cover the most common environment, if the POH doesn't cover for different situations you could call the manufacturer to get clarification. For example, in winter in Fairbanks Alaska we started with a max motor, (limit for the starter). This by the way was to warm the engine, and prevent hard starts, motoring the engine does not cool it down on an initial start. It does cool it after it has been ran, and is the proper way to cool it to prevent warping and thermal shock. The average start however does not require to hold the start any longer than neccassary, it will just cause your starter and related components to wear quicker than they should.

[aeroscout]

I know it might be apples and oranges, but the RFM for the L4 I fly recommends TOT between 716 and 826, less than 40 sec start. Basically in/above the yellow.

 

It says starts below 716 and greater than 40 sec may be detrimental to turbine components.

 

This may differ from the B model, but I was taught a fast hot start is better than a cool one.

 

Is that a modulated start ? The problem for the unmodulated start is it's difficult to impossible to predict the peak temperature of the start, and once fuel is introduced you really have no further control of temp short of cutting the fuel back off again. That's one reason why peak N1 starts give you the best shot at achieving a start without overtemping.

[Pohi]

Yeah, modulated start on the ones I fly

[helonorth]

I also didn't emphasize enough the importance of locking on to TOT from lightoff until peak TOT, and TOT receding, with the other instruments in peripheral vision. I disagree with your assessment of not wanting the coolest possible start. Cooler starts will ensure the longest engine life. There will be added load on the battery achieving peak N1, but not by much, and to me it's worth it. If you have never heard of peak N1 prior to lightoff I can only conclude you haven't been around turbines too long. No offense.

I have a few thousand hours in turbines but that, of course, is not important. I guess I don't even know what you mean by "peaking and stabilizing." If you think winding the N1 until it won't climb any further, as being "stabilized", I would disagree. I would call that "engaging the starter until the N1 won't climb any further, then adding gas" (something I have never been taught or seen in the FM). RR wants you to light it off at 15% and I think that's what you should do. How high do you let the N1 get before you add the gas? You will be lucky to any more than 15% on a cold morning, anyway. You can start your helicopter any way you want to, but I have found following the manufacturers recommendations as the best way to avoid problems. I do not believe cooler starts will do anything for you (or your engine) except make you feel better.

 

While $325 an hour for some 206 time is probably not a bad deal, I think turbine time and transtions are basically a waste of money for an upcoming pilot. When the time comes, someone will PAY YOU to learn how to start a turbine the way THEY want you to start it. It will probably be exactly the way the way it is written in the FM. The couple of starts and a few hours of cross country time mean nothing to the person that will hire you for your first turbine job.

 

Something that has no been mentioned, but I think is most important: make sure the throttle is closed before you hit that little button. It's sounds stupid, but it happens. I've never hot started (knock on wood) but seen plenty. The only time damage was found on the ones I've been around was when somebody left the throttle open. Then you have a real problem You don't have to be afraid of starting a turbine as long as you pay attention to what your doing. Many bigger operators will have a sim that you can hot start as much as you want. Takes a little of the pressure off when you press the starter for the first time in a turbine.

 

One more thing. What happens if he lets you start this thing and you panic and hot start it? The guy next to you very likely will not be able to save it. Do it on the job, the worst that will happen is you will get your walking papers. In this situation, you could get sent a bill for tens of thousands of dollars.

Edited December 24, 2011 by helonorth

[iChris]

I also didn't emphasize enough the importance of locking on to TOT from lightoff until peak TOT, and TOT receding, with the other instruments in peripheral vision. I disagree with your assessment of not wanting the coolest possible start. Cooler starts will ensure the longest engine life. There will be added load on the battery achieving peak N1, but not by much, and to me it's worth it. If you have never heard of peak N1 prior to lightoff I can only conclude you haven't been around turbines too long. No offense.

 

Long cool starts can also cause problems: As a side note, the Bell 206B II may have one of two fuel controls installed, the Bendix or Chandler Evans Company (CECO). Jumping into a 206B II with a CECO and trying to start it like the Bendix could end in a Hot Start. The CECO needs to be modulated.

 

Edited December 23, 2011 by iChris

[Gomer Pylot]

Rolls-Royce (formerly Allison) has never recommended cool starts. They say fast starts are much more important, and stress the engine less. Starts on C20, C28, and C30 engines should be well into the yellow, near the top, to get the quickest start. This is not my opinion, it's what RR says in writing. Getting the N1 too high puts too much airflow into the combustion chamber, moving the fireball too near the walls, and stress the engine unnecessarily. The best way to start it is exactly the way the RFM says - light it off as soon as the N1 reaches the recommended point and start it as hot as you can without exceeding any limitations. Cranking the N1 up high before lighting it off also uses up lots of battery capacity, and there is never that much in reserve. Running the N1 until it quits rising is a bad idea, IMO. And FWIW, I've been flying 206s since 1980, with over 10,000 hours and about that many starts, without ever having a hot start. Read the RFM and follow the procedures, and watch the TOT, particularly the rate of rise, very carefully. I pay less attention to what the TOT is than to what it will be in another second.

[palmfish]

I'm surprised nobody has mentioned that the N1 start limits are based on Free Air Temperature. In every aircraft I have flown with the 250 C20, the N1 minimums are as follows:

 

Above 7° C = 15%

-18°C to 7° C = 13%

Below -18° C = 12%

[SBuzzkill]

I mentioned it less specifically in my post #30. We'd always note out loud the temperature when starting the 206.

[Goldy]

Wow, this post took quite a turn...at least the OP now knows everything about starting a 206!

[aeroscout]

Wow, this post took quite a turn...at least the OP now knows everything about starting a 206!

 

I don't ever think I will know everything about anything. I would just be happy knowing everything important about something. What I do know is this. In 7,500 hours of turbine flying, I have never had a hot start. I have had 2 or 3 near hot starts that required nearly lightning quick reflexes from going hot, and not being happy about it. Once that TOT starts racing it's like a blur.

If I never have to experience another it would be too soon. Maybe as a result I go too far to the other side, but my first turbine time startups were taught to me as peak N1, and have served me well. I will review all this information forum members have provided, and see if it will temper my thinking. Improvement is almost always possible.

 

By the way, not complaining, but the topic has somewhat derailed. But some very interesting discussion has followed.

Edited December 24, 2011 by aeroscout

[aeroscout]

After reviewing my RFM, I found a chart similar to those posted....

 

 

Use the following guide for desired N1 starting speed versus outside air temperature.

N1 RPM TEMP °C (°F)

15% Above 7° (45°)

13% -18 to 7° (0 to 44°)

12% Below -18° (-1°)

 

 

 

The use of the word "guide" is, in my opinion minimum N1 speeds most likely to result in a non hot start.

When I look at the only engine I have exclusively operated from delivery new from factory, and operated to first scheduled hot section inspection at 1,500 hours, the factory found no abnormal wear, and returned to service with all original components. I used peak N1 on all starts. I had a couple of battery changeouts during that time, but each battery exceeded it's projected service life. I only occasionally used cart starts. I am led to conclude my technique works very well with proof to show for it. I couldn't find some of the other suggestions that were offered in the manual. The one suggestion about the flamefront getting too close to the combustor wall was intriguing, but I couldn't find that in the manual either.

[helonorth]

I wouldn't conclude much from one engine and 1500 hours and it definitely doesn't prove anything. Now RR has concluded that the best way to start a C-20 is at 15%, probably based on thousands of engines. Don't be a test pilot. Leave that to the test pilots. Sometimes I wonder why they even bother writing a FM.

[Gomer Pylot]

I got the information about the fireball containment from a RR tech rep, some years ago. I'm not certain whether it's in writing anywhere, but if so it's probably in an RR tech document. That sort of thing doesn't go into an RFM. They don't usually say why, just what.

[jimbo2181]

I'll take this even further off topic. Surprised no one has mentioned this.

 

Astar B2 RFM tells you to wait for a certain N1 to introduce fuel. I can't remember the exact number as it has been a while. If you do this you will get hard ignitions with fast temperature spikes that can (and do) cause the pilot to yo-yo the TOT. Turbomeca's recommendation is to introduce fuel immediately after hitting the starter button. This creates a nice slow climb of the TOT into the starting temperature range.

 

Most operators (I've been to 3 seperate ones) teach pilots the Turbomeca recommended procedure and tell pilots to ignore the RFM. The issue has been raised to Eurocopter who refuses to change the RFM.

 

I guess my point is I would even go a step further and follow the engine manufactures recommendations, not the airframe manufacturer.

 

Finally I can also add that I have never heard of "peaking" N1. Follow the recommended procedures as they are much much much smarter then us stick wigglers.

[Gomer Pylot]

The Sikorsky S76A++, which also has Turbomeca Arriel engines, says you should go to idle immediately after pressing the starter button. IME, if you have a choice of introducing fuel a percent or so low or high, low is better. In the 206L3, I start moving the throttle at 10%, so as to insure lightoff at or below the recommended 12%. You don't want to start too low, but a percent or so low will tend to give smoother, quicker, and cooler starts. Running it above 12% will give you a whoosh like a C20, and the TOT will rush up there.

 

I would always recommend reading and heeding the RFM, but for engine parameters I would defer to the engine manufacturer's recommendations, if different from the RFM. It's unusual to see much difference, though.

Edited December 24, 2011 by Gomer Pylot

[aeroscout]

All this was a very interesting diversion. Back to topic. This proposed ferry is at my expense, I will be renting it. The rental rate is $850/hr. It won't be some company sponsored thing, deadhead or repositioning. So if I can't defray the flight time cost I personally am stuck with it. I get the sense that some think I am trying to make money on the deal. I'm not. I stand to get stuck with the whole bill. If someone can get some discount time and appreciate it, so much the better.

[rotormandan]

IME, if you have a choice of introducing fuel a percent or so low or high, low is better. In the 206L3, I start moving the throttle at 10%, so as to insure lightoff at or below the recommended 12%. You don't want to start too low, but a percent or so low will tend to give smoother, quicker, and cooler starts. Running it above 12% will give you a whoosh like a C20, and the TOT will rush up there.

 

Very interesting. I have always had the opposite thought that lighting off earlier would cause a hotter start as the compressor isn't bringing in as much air. That is why I assumed that you can light off earlier with cooler air as the rfm states.

 

I peak the N1 if i have to start up with in 20 min after the last shutdown. In the summer that peaked n1 Is what it takes to get below 150. I fly a 206b2 and b3. Our b3 is manually modulated with the ceco system. It's a bit intense when starting warm. The b2 has the bendex (snap start) so it's not as bad. Yes I pay attention to the starter time limits and when I say peaked n1 I'm going off of the sound. You can hear that it's spinning as fast as it's going to get off of the battery alone. Usually around 18%+-

 

All this was a very interesting diversion. Back to topic. This proposed ferry is at my expense, I will be renting it. The rental rate is $850/hr. It won't be some company sponsored thing, deadhead or repositioning. So if I can't defray the flight time cost I personally am stuck with it. I get the sense that some think I am trying to make money on the deal. I'm not. I stand to get stuck with the whole bill.

 

 

You should have said this in the beginning. I'm glad to hear you're not another greedy company trying to rip off a struggling time builder. Most of the ferry offers on this site are just looking for some extra cash for a flight that's going to happen anyway. While I don't think it's a bad idea if a student building time for a rating or something can get a 206 for the price of an r44 or 300, it's not worth it if it's going to cost any extra debt. Most companies charging for a flight they're going to do anyway should just offer a free seat. "Hey low-timers, pay your way out here and you can have a free seat in a turbine ship." Why not use those extra seats to give back for all those times someone helped you high timers out? Now one gets that far without a little help. I'm not a high timer but I haven't gotten this far without any help. That's for sure.

Edited December 25, 2011 by rotormandan

[SBuzzkill]

Not a bad deal at all.

[Gomer Pylot]

If the engine is still hot from a previous run, I just motor the starter up to 10% or so and release the starter, letting the airflow cool the engine. You can see the TOT drop even as the engine slows down. I let it come to a complete stop, and then initiate the start. The TOT is usually down to well below 150 by then, and the second run up to lightoff gets it well below any dangerous temperature. IMO that uses less battery, is easier on the starter, and gives a better start. Winding up the starter too high, too often will eventually cause it to fail.