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Piper Meridian PT6-42 - Hot start, or not?

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Piper Meridian PT6-42 - Hot start, or not?

Old 17th Apr 2017, 17:27
  #41 (permalink)  
 
Join Date: Apr 2005
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If you look at most mfr's charts the book numbers work at 96% N1, if you have a good engine, it should then be somewhere around 80c under redline"ish". With 3 shutdowns on pt6's i am very conservative wrt engine management. Most batteries have a rather finite life, how many hours/how old/how many cycles on your battery
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Old 17th Apr 2017, 18:06
  #42 (permalink)  
 
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Originally Posted by rigpiggy View Post
The reason to hold the props is in cold environment, you will damage the gearbox, and or blow prop seals when they come out of feather. The standard arctic first flight is f/o holds the rhs, startup run until oil temp comes up, battery charges, run over to lhs, does the next start, crawls in through back.

Though the preferred method is to run a janitrol through an exhaust stack, not always available
I'm not sure. In the cold season, I always overnighted in locations where the engines were plugged in with blankets wrapped around the engines to keep them warm. Only tried to hold a prop once on start and it seemed like it would be difficult to do so for very long with the engine spooled up to idle.
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Old 18th Apr 2017, 04:37
  #43 (permalink)  
 
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My apologies everyone. A brain failure, I meant the temps 735/740 not 400s
I fly -42s in b200 these are prone to cracked cans if run to pratts temp limits.
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Old 18th Apr 2017, 04:53
  #44 (permalink)  
 
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Originally Posted by JammedStab View Post
I'm not sure. In the cold season, I always overnighted in locations where the engines were plugged in with blankets wrapped around the engines to keep them warm. Only tried to hold a prop once on start and it seemed like it would be difficult to do so for very long with the engine spooled up to idle.
I can tell you it isn't a problem. Used to torture my old boss, run underneath the porter and make him think he forgot the prop tie... Yes, yes I am!!!
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Old 18th Apr 2017, 04:57
  #45 (permalink)  
 
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Originally Posted by JammedStab View Post
I'm not sure. In the cold season, I always overnighted in locations where the engines were plugged in with blankets wrapped around the engines to keep them warm. Only tried to hold a prop once on start and it seemed like it would be difficult to do so for very long with the engine spooled up to idle.
Lots of places you don't overnight, but 4 hrs at-40 will suck the temps out of even a wrapped engine. As long as the flow dividers didn't freeze-30ish it would start. Otherwise it would start but not accelerate past 30-35percent
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Old 18th Apr 2017, 10:55
  #46 (permalink)  
 
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Not if it is plugged in. We used to leave the aircraft plugged in at -35 and 30 knot winds for a as long as three days at one location. No start problems. I'm sure there were others who left the aircraft at -40 as well. Never heard of an issue.

We had a plug for each engine, battery removed(yes it is very heavy, but I had a good technique to prevent back injury during removal), engines wrapped(try that alone in 30 knot winds), a heater fan in the cockpit and props tied. All the job of a good new first officer.
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Old 28th Apr 2017, 06:03
  #47 (permalink)  
 
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This Piper wouldn't be HS-TOM, would it?
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Old 28th Apr 2017, 09:49
  #48 (permalink)  
 
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[QUOTE=JammedStab;9739292]Speaking about getting a higher rpm on a free turbine engine prior to introducing fuel, I was told once that if you left the propeller tied in place during the start(we used to tie them down on the Twin Otter to keep them from rotating in a strong wind while shut down), you could get an extra 1 or 2% rpm. Never tried it of course, has anybody else.
[QUOTE]
Never tried this for cold starts as I almost never flew anywhere seriously cold but >20 years ago we tried this "for sport" on ferry flights when we had to start the engines without a marshaller and the copilot would stand outside and check the area.

It was no problem holding the prop of even the (then) strongest PT6 variant with one hand but once you let go of it you probably would not have been able to catch even the next blade, so swift and strong was the acceleration.

As for the OP, good luck with your swift Piper and should you ever need to trade up a PC-12 would probably be a good choice

As for the hand cranking, the one who recommended it probably had Garret engines in mind which AFAIK sometimes required hand cranking after shutdown to prevent bending.

There are CF34 engines with FADEC that will not even turn on fuel before the ITT has dropped to a certain value but they are bleed started and can run the starter for 2 minutes which is probably too much for most electric starters.
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Old 28th Apr 2017, 18:36
  #49 (permalink)  
 
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FWIW - The VH-3s of the presidential fleet (T58 engines) have rotor brakes to "park" the helo rotors, and at the same time the free turbines. They are generally started in this mode, and don't start turning until the brake is released.
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Old 29th Apr 2017, 00:11
  #50 (permalink)  
 
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Isn't that true of all SH-3 models (of which the VH-3 is a derivative)?
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Old 10th May 2017, 17:58
  #51 (permalink)  
 
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Probably, although I used the VH-3 as a widely visible example.
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Old 12th Oct 2018, 16:45
  #52 (permalink)  
 
Join Date: Mar 2009
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MeridianPilot:

Just came across this so I imagine you've figured out a procedure for everything by now, but just in case...

Removing ground power: I did some of the initial powerplant installation work at Piper for the Meridian. I was also one of the first engineers to fly on the prototype other than the test pilots. I was working the ECS system. ALL the initial starts were powered by a cart and yes it's windy for the guy pulling the plug, but not a problem.

I am now doing certification for a new battery that would be perfect for this application. You can consider it to be your own personal APU. It will vastly outperform lead acid and save you a few pounds in the process. It will be one of the first batteries to pass the new regulations that came out this year 2018. -40? No problem. Internal self powered heaters make short work of that. Helicopter testing says it should last on wing for years while producing 3 times as many starts; that operator gets 3-4 months before replacement of their current batteries. I am waiting to watch it pass the thermal containment test though. Then I'll believe it safe for use. It won't be cheap but nothing good rarely is.
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Old 21st Oct 2018, 01:26
  #53 (permalink)  
 
Join Date: Apr 2005
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Originally Posted by JammedStab View Post
Not if it is plugged in. We used to leave the aircraft plugged in at -35 and 30 knot winds for a as long as three days at one location. No start problems. I'm sure there were others who left the aircraft at -40 as well. Never heard of an issue.

We had a plug for each engine, battery removed(yes it is very heavy, but I had a good technique to prevent back injury during removal), engines wrapped(try that alone in 30 knot winds), a heater fan in the cockpit and props tied. All the job of a good new first officer.
hard to plug in or get fuel when some meathead in his atr won't move from the pumps/plugs
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