Turbine bypass
12-12-2007, 01:49 PM
#2
My Feedback: (1)
RE: Turbine bypass
Pro's
1. Less drag, smoother airflow through the inside of the airplane than a non-ducted installation.
2. Cleaner install (if done properly)
3. Less chance of equipment inside the plane coming into contact with the turbine (either fod in the intake, or melting onto the side of the case).
4. More protection for the turbine in a crash
5. Might also help avoid having fuel spray come in contact with hot engine parts in some crashes (less chance of a fire)
6. Easier for inexperienced builders to set up a bypass system that is pre-engineered without making mistakes.
Con's
1. More difficult turbine access.
2. Much more difficult to scratch build using a bypass because the ducting and fuel tanks need to be designed and built to fit the airplane.
3. After engine shutdown the radiant heat from the turbine will be contained inside the bypass, necessitating the use of a fan to help with cooling (yes I realize this is a good idea even if you don't run a bypass, but it is pretty much mandatory with one).
4. Takes up more space inside the airplane.
5. Higher cost.
6. Some propane start turbines are more likely to "BANG" on startup inside a bypass (usually doesn't hurt anything, but it gets everyone's attention).
I'm sure there are more on both sides...
1. Less drag, smoother airflow through the inside of the airplane than a non-ducted installation.
2. Cleaner install (if done properly)
3. Less chance of equipment inside the plane coming into contact with the turbine (either fod in the intake, or melting onto the side of the case).
4. More protection for the turbine in a crash
5. Might also help avoid having fuel spray come in contact with hot engine parts in some crashes (less chance of a fire)
6. Easier for inexperienced builders to set up a bypass system that is pre-engineered without making mistakes.
Con's
1. More difficult turbine access.
2. Much more difficult to scratch build using a bypass because the ducting and fuel tanks need to be designed and built to fit the airplane.
3. After engine shutdown the radiant heat from the turbine will be contained inside the bypass, necessitating the use of a fan to help with cooling (yes I realize this is a good idea even if you don't run a bypass, but it is pretty much mandatory with one).
4. Takes up more space inside the airplane.
5. Higher cost.
6. Some propane start turbines are more likely to "BANG" on startup inside a bypass (usually doesn't hurt anything, but it gets everyone's attention).
I'm sure there are more on both sides...
12-12-2007, 03:25 PM
#3
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RE: Turbine bypass
inside a bypass your get dynamic thrust. If you want speed this is the way to go...
no bypass you get greater static thrust. If you want 3D performance this is the way to go...
no bypass you get greater static thrust. If you want 3D performance this is the way to go...
12-12-2007, 04:14 PM
#4
RE: Turbine bypass
How about
Without the bypass ( or at least without the top of it ) air now flows into the engine ( front and back ) then the pipe making the opps. cooler at all times because the air is in motion and not trap or restricted by the top of the bypass.
My 2cts. [8D]
Without the bypass ( or at least without the top of it ) air now flows into the engine ( front and back ) then the pipe making the opps. cooler at all times because the air is in motion and not trap or restricted by the top of the bypass.
My 2cts. [8D]
12-12-2007, 04:29 PM
#5
RE: Turbine bypass
FWIW, having read almost every thread posted in the jets forum over the past 6 years, Kevin's response above is about the best answer that has ever been posted on this topic, and in my opinion, beyond the obvious (which Birdofpray chimed in with [although there are some that would disagree] regarding static and dynamic thrust) Kevin's response provides enough detail that I would point people to this thread in future discussions of this.
Well done!
Well done!
12-14-2007, 04:04 AM
#11
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RE: Turbine bypass
ORIGINAL: KC36330
a wet start isn't as easily seen in a bypass installation
a wet start isn't as easily seen in a bypass installation
Mine are transparant ! (On the pic below this SpiderJets turbine bypasses are cut off at the rear to fit with the standard bellmouth of the JetLegend L-39...)
No heat issues, even with this JetCat P-160 installed.
I still have some stocks... PM me if interested...
Nicolas.
