Syncing props on the takeoff roll. Yes or no?
- Thread starter dasleben
- Start date
aloft
New Member
Full-throttle in a turbocharged engine can over-psi the manifold pressure, a condition called "overboost".
Oh no you di-int!
+1
...and I'm not sure if I want to be their mx or not. On one hand, you could get rich fixing the problems they're causing. On the other hand, they'll probably fire him and hire someone else because it will end up having so many problems.
That's not necessarily accurate. Sometimes, you push the throttles all the way up and the MP comes up to where it should.
How about "in piston airplanes, always use full rated power for every takeoff every time".
Be nice to your engines, folks.
-mini
aloft
New Member
That's why I said "can", not "will".
meritflyer
Well-Known Member
aloft is correct for the most part. Turbocharged airplanes require some serious mixture and power attention.
In older turbocharged airplanes, throttle travel is only about 3/4 forward to take off power. Anymore, and you'll damage the engine if not rapidly corrected. Even in new turbocharged airplanes which allow for full throttle travel to achieve maximum MP, if the temperature if below nominal, you'll overboost the engine.
As a matter of practice in turbocharged engines, 98% of the time I'll do a static takeoff and actually "set power". To complicate the matter, in older turbocharged airplanes, you actually adjust the mixture to achieve a specific TIT during the takeoff roll after power has been set.
jynxyjoe
Queso King
It's almost like I've never flown a turbocharged airplane before...
:dunno::beer:-mini
dasleben
That's just, like, your opinion, man
Sounds like crappy engines! The 402C (airplane made in the late 70s, early 80s) with TSIO-520-VBs has you push the throttles to the firewall. The wastegates take care of the rest. The only time you have to pay attention is on colder days when the oil is still cold. You might have to pull the throttles back just a little bit to keep it at 39" MP.
No messing with TIT or anything (hell, we don't even have one of those gauges). Mixtures full, props full, throttles full. The only time I do a "static" takeoff to set power is for accel-stop or accel-go considerations.
No messing with TIT or anything (hell, we don't even have one of those gauges). Mixtures full, props full, throttles full. The only time I do a "static" takeoff to set power is for accel-stop or accel-go considerations.
KSCessnaDriver
Well-Known Member
3/4 for take off power? Heck, the Turbo Arrow I flew barely needed 1/3 throttle movement to get to takeoff power. Almost scary the first time I flew it, but its not hard to get used to.
meritflyer
Well-Known Member
It's almost like I've never flown a turbocharged airplane before...
-mini
I'll be here all week.
Don't you guys do an engine warm-up as necessary before boarding the pax? Not a run-up, necessarily...but enough to get temperatures and pressures back up into the green arcs if they've cooled off?
-mini
dasleben
That's just, like, your opinion, man
No, not generally. It usually doesn't take too long to bring the temperatures up anyway. I'll do a warmup before boarding though if we need to get sprayed for deice and ground icing is a problem.
gomntwins
Well-Known Member
We fly both. You know how finicky the power and speed levers are in the metro. I'd be lucky to get the power levers properly set on the takeoff roll most of the time.
In cruise the props are out of sync and you adjust the speed levers to get them into sync. Then theres a split in torque. So you adust the torque so there's no split. Then the props are out of sync again. You adjust this for a few minutes before you finally give in a just take the split in torque or the out of sync props. It's an evil game.
Split in Torque? Wait... you mean the rigging on a Metro isn't always perfect? hahaha! Listening to the mechanics talk about rigging a Metro is funny... it really sounds like a cluster! They try hard on the ground but you never really know what you're going to get until you take it flying after re-rigging.
jtrain609
Antisocial Monster
Which would mean you would takeoff with full rated takeoff power, which has nothing to do with the position of the throttle in the cockpit.
So you're still not doing a partial power takeoff, you're just using the full rated horsepower for takeoff. Anything more would be beyond the limits of the engine.
ppragman
No pasa nada.
In the cargo config in the C model, they just removed our prop syncs, and it sucked, especially when I didn't have an ANR headset yet. Lame-oh.
Inspector, a federali through and through. The runway was 7000 ft long so it wasn't really a huge concern. I agree thats theres no takeoff data for it but the plane will get off the ground in maybe 2000 ft....it's been a while since I've done. I wouldn't do it if I had any doubts about the runway length but it was no big deal at the time.
This one time....in the 1900.... Hahahah
deadstick
Well-Known Member
Type I = one pilot , type II= 2 pilots
Running joke :"I am the prop sync!"
Yea, but who around here flies Connies?
As for the TSIO360-FB and the 520-NB, it seems like you could get take off RPM/MP at a lower throttle setting, but the MP would come back down as everything caught up, and then you would continue to advance the throttle backup to the max mp.
aloft
New Member
True, but full-rated power for takeoff in a turbo is generally overkill. If a normally-aspirated 182 can take off with only 24", so can a turbo'ed one.