Recover from hot start
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I try just running JFS and not start engine, RPM stay up for approx. 4 minute, then JFS overheat and RPM die slowly.
I try hot start to 750-800C, it goes to 200C >4 minute.
Is JFS use higher in hot start or engine fire? -
Just follow procedures and everything will be fine
I don’t understand what you are doing
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I cannot follow procedure because things happen not according to Dash 1. Engine RPM die before FTIT get to correct temp so recover from hot start not possible without restart mission.
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Just follow procedures and everything will be fine
I don’t understand what you are doing
Well, he intentionally hot–starts the engine, then tries an abort/restart–procedure as described in the quote above: Throttle to cut–off, let temp cool down while keeping jfs running, once temp goes below 200 attempt a restart by moving throttle up to idle again. JFS is supposed to maintain RPM throughout this whole cool–down / restart process.
As I understand, his complaint is that this procedure doesnt seem to work in BMS because the JFS doesnt keep the engine RPM above 20% long enough for the engine temperature to come down below 200 degrees.
There is always something… ;–)
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Well, he intentionally hot–starts the engine, then tries an abort/restart–procedure as described in the quote above: Throttle to cut–off, let temp cool down while keeping jfs running, once temp goes below 200 attempt a restart by moving throttle up to idle again. JFS is supposed to maintain RPM throughout this whole cool–down / restart process.
As I understand, his complaint is that this procedure doesnt seem to work in BMS because the JFS doesnt keep the engine RPM above 20% long enough for the engine temperature to come down below 200 degrees.
There is always something… ;–)
The procedure never says that the Jfs will rum until cool down
It is impossible to say so because the jfs could run 3 minutes before pilot inject fuel and might have a hot start
The procedure says
Let the engine cool down below 200 before attempting another start
Let the jfs run to ventilate
It does not say jfs will run fully during the procedure or that rpm will stay at 20 during the procedure
You might then have to recharge your jfs to restart
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Thank you Hornet.
The procedure never says that the Jfs will rum until cool down
I try hot start, JFS on, but only maintain RPM for 1.5 minute
I just run JFS (do not start engine), JFS can maintain RPM for approx. 4 minute
So why JFS keep RPM for 4 minute no engine start but only 1.5 minute on hot start? On my testing, I hot start automatic by putting throttle in idle (not cutoff) before JFS start so engine hot start always.The procedure says
Let the engine cool down below 200 before attempting another start
Let the jfs run to ventilate
It does not say jfs will run fully during the procedure or that rpm will stay at 20 during the procedure
You might then have to recharge your jfs to restartIt does not say RPM will drop after 1.5 minutes, it does not say I have to recharge JFS.
What does it say?
immediately pull the throttle back to CUTOFF and let the FTIT decrease to 200°C while the JFS is running, before attempting another engine start.
After moving the throttle back to the CUTOFF position (click idle detent if necessary) keep the JFS running as it helps to cool down the engine. Allow FTIT to fall to 200°C before advancing the throttle to IDLE to attempt another engine start.
Imply that JFS run and will maintain requirement for “another engine start” which is RPM >20%, no? Imply that one charge of JFS can do more than one engine start, no?
Nothing about recharge JFS. -
I understand wanting to get the hot start procedure down. But don’t you want to get the aircraft in the air and actually fly it.
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Still will not help me learn hotstart if I skip it
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Your situation is the same as before.
1.make sure your launcher has cut off.
2.confirm that the throttle is in the off position and turn on JFS2
3.at this time, the speed will slowly rise and stop at 25%
4.fix the throttle to the IDLE(70%) position, and continue with other ramp start programs. -
Still will not help me learn hotstart if I skip it
sorry but i dont know WTF you are doing
The JFS running time is 4 minutes (normal condition) + 4 Minutes (heating) totally independant from anything else, it will run the same time @RPM20 or while ventilating.
After 8 minutes, the JFS will be broken and will shut down (your jet is dead then)
Of course, this is assuming that:
- you dont move your canopy when operating the JFS
- you dont use any time compression
That means you have PLENTY of time to ventilate with JFS and restart
here is a video i just made to teach you:
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I’m slowly learning more about JFS which I have some kind of learning block about. I’m going to write some things and please tell me what details (or major concepts even) I’m wrong about.
You can’t think of JFS having a “charge.” JFS’s charge is all the fuel in the airplane and will run forever*.
*Not actually forever as JFS has other limits and characteristics but it has nothing to do with the accumulator energies.
What has a charge (or 2) are the brake/JFS accumulators. The accumulators are only to get the JFS running and thereafter are irrelevant unless the JFS stops running without engine start and JFS must be started again. Recharging of accumulators is done via hydraulic system pressure or manual pumping. JFS power alone will never recharge accumulators.JFS continual run prior to ground start is limited to 4 minutes by written regulation. The RPM during motoring varies based on engine model and environmental conditions. Presumably a real F-16 JFS can run for somewhat longer than 4 minutes at the risk of damage or automatic shutdown. This would explain why in certain conditions JFS may shut down automatically earlier or later than 4 minutes, especially earlier following a hot start.
In the above video the FTIT was below 200C in about 38 seconds. By written regulation 1 minute wait time is needed between start attempts. If the FTIT doesn’t get under 200C before the 4 minute motoring limit or JFS shuts itself down then you have to have JFS off for 5 minutes and manually recharge accumulator if necessary before the next attempt. There is no guarantee that a second start attempt on the same JFS run is possible. It probably helps to react as quickly as possible to the hot start to limit the fuel and heat that needs to be removed.
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I’m slowly learning more about JFS which I have some kind of learning block about. I’m going to write some things and please tell me what details (or major concepts even) I’m wrong about.
You can’t think of JFS having a “charge.” JFS’s charge is all the fuel in the airplane and will run forever*.
*Not actually forever as JFS has other limits and characteristics but it has nothing to do with the accumulator energies.
What has a charge (or 2) are the brake/JFS accumulators. The accumulators are only to get the JFS running and thereafter are irrelevant unless the JFS stops running without engine start and JFS must be started again. Recharging of accumulators is done via hydraulic system pressure or manual pumping. JFS power alone will never recharge accumulators.JFS continual run prior to ground start is limited to 4 minutes by written regulation. The RPM during motoring varies based on engine model and environmental conditions. Presumably a real F-16 JFS can run for somewhat longer than 4 minutes at the risk of damage or automatic shutdown. This would explain why in certain conditions JFS may shut down automatically earlier or later than 4 minutes, especially earlier following a hot start.
In the above video the FTIT was below 200C in about 38 seconds. By written regulation 1 minute wait time is needed between start attempts. If the FTIT doesn’t get under 200C before the 4 minute motoring limit or JFS shuts itself down then you have to have JFS off for 5 minutes and manually recharge accumulator if necessary before the next attempt. There is no guarantee that a second start attempt on the same JFS run is possible. It probably helps to react as quickly as possible to the hot start to limit the fuel and heat that needs to be removed.
SORRY i should have been more precise
There is absolutly no LIMIT of 4 Minute for JFS running.
After 4 Minute, the JFS will start to heat, indicated by a slow flashing Lamp
after 8 Minutes, the JFS will suffer damage from heating and switch off, indicated by a quick flashing lamp.
So, normally you have 8 minutes of JFS running before JFS going off ……
in conclusion :
i still dont understand what PutYawa is talking about when he says his JFS turns off prematurly.
We probably
- move his canopy
or
- switch off his main power switch
or
- switch off his JFS
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Thank you for video, it is exactly what I expect to happen but is not happen for me.
In TE 01, I close canopy at start just for noise and not move canopy after. Dash 1 says this on page 166
2. Moving forward you can close the canopy (spider). It is advisable to do so before engaging the JFS.
so close canopy should be OK, no?
I do not switch off JFS switch or anythin, just leave aircraft alone, wait for FTIT to cool. When put throttle back to CUTOFF, engine RPM die slowly. Is JFS consume? Maybe, or not. Is JFS off prematurly? Maybe, or not. But engine RPM die slowly, by time FTIT is 200C, RPM is 0%. Why engine RPM die if JFS still running?
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Thank you for video, it is exactly what I expect to happen but is not happen for me.
In TE 01, I close canopy at start just for noise and not move canopy after. Dash 1 says this on page 166
so close canopy should be OK, no?
I do not switch off JFS switch or anythin, just leave aircraft alone, wait for FTIT to cool. When put throttle back to CUTOFF, engine RPM die slowly. Is JFS consume? Maybe, or not. Is JFS off prematurly? Maybe, or not. But engine RPM die slowly, by time FTIT is 200C, RPM is 0%. Why engine RPM die if JFS still running?
Please make a video
Are you sure you don’t have an engine fire ?
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What program best to make video? I try again, I remember some try engine fire mabye, other try no engine fire. Is engine fire = no restart?
I wait until FTIT at 700-800C range as stated in manual, do not remember checking for engine fire. -
What program best to make video?
=> https://lmgtfy.com/?q=How+to+make+in-game+video+captures%3F
nVidia integrated tools
OBS
FRAPS
BANDICAM
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Yes, canopy operate is fine if completed before engine start. You want minimal electric system draw during start. I think in real airplane it is a bad idea to open/close canopy 100 times before which might drain battery but I don’t think this matters for BMS.
Only thing I can think is you are allowing RPM to increase during start so JFS turns itself off and when you select cutoff.
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I allow RPM to increase to above 750 and throttle go CUTOFF before 800 since Dash 1 says “If you see FTIT rising at an alarming rate or go above 750°C you are encountering a hot start”
Not sure if JFS is off but I do not turn it off and during cooldown, the JFS sound still on, light still on, switch still on Start 2 position. -
That with the canopy is just plain WRONG. Here’s the proof. There is no problem closing canopy with just started JFS.
Look at video 3:34 onwards … Actually it is Thunderbird’s F16 .
SO… BMS is WRONG in this matter… just dare to say its fake
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That with the canopy is just plain WRONG. Here’s the proof. There is no problem closing canopy with just started JFS.
Look at video 3:34 onwards … Actually it is Thunderbird’s F16 .
SO… BMS is WRONG in this matter… just dare to say its fake
no it’s not wrong,
it’s not systematic, there is a PROBABILITY that JFS shuts down in BMS when closing canopy, as in real
refer to proper engineering documentation