Turbo-charged engine handling
Thread Starter
Join Date: Nov 2005
Location: Australia
Posts: 185
Likes: 0
Received 0 Likes
on
0 Posts
Turbo-charged engine handling
Just a quick question. How many inches/min should you bring back a 350HP turbo charged engine?
is 29" to idle (landing roll) in 3mins too short?
is 29" to idle (landing roll) in 3mins too short?
Have never flown one in my life, however I believe it is 2"/min pre ToD, and once below 25" can be handled like a high performance NA engine.
Does this mean you bought a Mojave?
Edit: Interested to know what the correct technique is!
Does this mean you bought a Mojave?
Edit: Interested to know what the correct technique is!
Join Date: Apr 2007
Location: BackofBourke
Posts: 346
Likes: 0
Received 0 Likes
on
0 Posts
"Have never flown one in my life, however I believe it is 2"/min pre ToD, and once below 25" can be handled like a high performance NA engine."
I don't know either, but thought I would post anyway.
I don't know either, but thought I would post anyway.
This is the sort of information that was passed on during endorsements.
Sadly, a lot of the people conducting the endorsements these days have no idea either.
The experience pool has all but dried up!
Sadly, a lot of the people conducting the endorsements these days have no idea either.
The experience pool has all but dried up!
Join Date: Feb 2006
Location: The Zoo
Posts: 335
Likes: 0
Received 0 Likes
on
0 Posts
This guy has more than a few opinions...
http://www.avweb.com/news/pelican/182544-1.html
...but their his opinions, if you listen to em, listen because they make sense not because of their "experience" (same rule of thumb for anyone... 1000hrs or 30,000hrs - not much difference when it comes to operating pistons and 29,000hrs out of the 30 are in Jets
The GFA also had some interesting notes on aerotowing and engine failure rates on engines that idle and descend at Vno compared to those at 2200rpm or higher at Vno.
My advice... run the engine the way the owner wants the engine run. It's their money, they're the ones that pay for the maintenance, it's their choice... even if you "know" better.
If it was my engine, I'd care about climb and proper use of cowl flaps. Cruise and Descents, honestly... what are you going to do at 29" and/or 75% or less power. That said, there's a lot of inertia in that engine, be gentle when you do make changes dont rip the throttle out of the firewall. Thing I'd be more concerned about is running it often - look at how many Flying Schools regularly make TBO, and look at how many Taxi's get significantly more km's by keeping the engines going 24/7 even when engines in both environments get "abused" signfiicantly.
My two cents and *more fuel on the fire*
http://www.avweb.com/news/pelican/182544-1.html
...but their his opinions, if you listen to em, listen because they make sense not because of their "experience" (same rule of thumb for anyone... 1000hrs or 30,000hrs - not much difference when it comes to operating pistons and 29,000hrs out of the 30 are in Jets
The GFA also had some interesting notes on aerotowing and engine failure rates on engines that idle and descend at Vno compared to those at 2200rpm or higher at Vno.
My advice... run the engine the way the owner wants the engine run. It's their money, they're the ones that pay for the maintenance, it's their choice... even if you "know" better.
If it was my engine, I'd care about climb and proper use of cowl flaps. Cruise and Descents, honestly... what are you going to do at 29" and/or 75% or less power. That said, there's a lot of inertia in that engine, be gentle when you do make changes dont rip the throttle out of the firewall. Thing I'd be more concerned about is running it often - look at how many Flying Schools regularly make TBO, and look at how many Taxi's get significantly more km's by keeping the engines going 24/7 even when engines in both environments get "abused" signfiicantly.
My two cents and *more fuel on the fire*
I was taught (and use) the 1 inch per minute rule. We use 31" in the cruise and start decreasing power 6 mins before the CCT where we want 25". Thats for 350HP Turbo charged engines. Was taught that by someone who has very good engine care traits.
Join Date: May 2007
Location: In a tube
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
Just do an inch per thousand feet. If your flying at low altitudes, just use common sense and start bringing it back early before the circuit. Don't let anyone tell you it's hard
Join Date: Jul 2007
Location: global
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts
Thermal shock is the enemy here. You obviously don't reduce from crz pwr to idle at 10000ft. This will crack pots! 1"/min(500ft) reduction on descent works well. This will look after CHT's. Once at circuit ht, you are "out of the woods". As in any a/c though, be smooth with any inc/dec pwr.
Join Date: May 2005
Location: Here and there.
Posts: 447
Likes: 0
Received 0 Likes
on
0 Posts
It's not rocket science guys (hope that doesn't sound arrogant). Trickle off 2 inches of MP for every 1000' on descent. Do it smoothly as you would with an engine that is not turbo charged. Plan to arrive in the circuit with around 20 inches on the tap. It's all about cooling. If you need to give it a skinfull at this point it'll be ok. Like everything do it smoothly. Albeit a long time ago we never cooked a donk through ignorance. Look after the engine and it'll look after you.
D
D
Silly Old Git
I know of a fleet of Chieftans that were FLOGGED
Never even heard of power reduction carry-on
Never had a SINGLE issue with the engines apart from mags and other things falling off
In PNG all 402s in my day anyway,were caned CONSTANTLY
Never had a problem.
Never even heard of power reduction carry-on
Never had a SINGLE issue with the engines apart from mags and other things falling off
In PNG all 402s in my day anyway,were caned CONSTANTLY
Never had a problem.
Join Date: Jan 2006
Location: Antipodea
Posts: 56
Likes: 0
Received 0 Likes
on
0 Posts
Man I enjoyed flying the Mojave. A man's aerplane as they say and requesting flight levels always gave a sense of self importance
I found an inch/ min, thousand ft etc etc all worked well when everything was tickety boo and even when it goes tits up e.g. after a go around then a recircuit to land then bringing the power back to 2 or 3 smooth motions over the course of the circuit never bothered her too much...
Happy flying!!
I found an inch/ min, thousand ft etc etc all worked well when everything was tickety boo and even when it goes tits up e.g. after a go around then a recircuit to land then bringing the power back to 2 or 3 smooth motions over the course of the circuit never bothered her too much...
Happy flying!!
Join Date: May 2002
Location: Permanently lost
Posts: 1,785
Likes: 0
Received 0 Likes
on
0 Posts
Thanks tinnie for some words of sense.
I suspect that there are more old wives tales about "shock cooling" in aviation than any other subject, especially in relation to operating turbo engines. I also suspect that there are more problems with going from low power settings to high too quickly than the other way.
That said, operate them the way the owner wants them operated and also take into consideration that abrupt power changes often scare the beejeesus out of pax. They need more careful handling than the engines.
I suspect that there are more old wives tales about "shock cooling" in aviation than any other subject, especially in relation to operating turbo engines. I also suspect that there are more problems with going from low power settings to high too quickly than the other way.
That said, operate them the way the owner wants them operated and also take into consideration that abrupt power changes often scare the beejeesus out of pax. They need more careful handling than the engines.
Have never flown one in my life, however I believe it is 2"/min pre ToD, and once below 25" can be handled like a high performance NA engine.
Join Date: May 2007
Location: nt
Age: 43
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
tinpis & plovet the theory of power on decents is not really an old wives tale. The big dirty old lycos handle a bit more abuse than the conts, never really seen many turbo lycos that had been treated with great love and care (skydive and remote wa rpt nevergo's and chieftians) and they just seemed to take it in their stride. But treat a highly strung and lightly built engine like a gtsio the same way and you might be noticing a few expensive repair bills. Apart from keeping the heat in the engine to prevent shock cooling you are also maintaining a manifold px suitable in keeping sufficient px on the pistion rings which will maintain them pressed against the cylinder wall preventing ring blow by and cylinder glazing. As for after landing, keep the rpm up and allow a good cool down period (3 minutes was recomended), not necissarly to cool the engine but to allow the turbo to have a bit of a chance to cool and not get carbon ladened by the oil cooking on the bearings.
Join Date: Feb 2008
Location: NZ
Age: 50
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
Nicely said ernie
when I was in Alice, a Chiefy turned up to start for Air North(I think) and they found 10 cylinders were cracked. It happens... usually from knuckle heads who couldn't give a preverbial.