Engine on fire what could it be ?

[jfri]

When I had started the engine on the MKI and came to the point of running up , open throttle and check boost. The I applied full throttle and soon I could se flames caming out of the engines exhaust tube. I don't understand why ? What could I have made wrong ? Another question here. According to the manual I should check boost at 6.5 lb/sq/in. But the scale only goes to 4 from what I can see. What am I missing ?

[Killratio]

Hi,

First of all, how long did you sit warming up for?

Next, did you wait until the Radiator Temperature was at 70C before openning up the throttle to full?.

Did you have the radiator fully open?.

Did you have the flaps down?

Basically the Mk I will give you little chance on the ground. The startup/run-up must be done quickly and efficiently as if you are not in the air by 8-10 minutes maximum (on a cool day!) you can easily have the temps go too high. If you combine that with low coolant or damage or fault, you can catch fire. The radiator is almost fully obstructed on by the landing gear and flaps when they are down. Any time the radiator hits 140C you are getting to be at high risk of fire. Anything above 120C is "bad" to run.

OR..you could have had a problem from an earlier flight, they Accusim aircraft are "persistant", that is, you get the aircraft in the same condition as you left it last flight.

If you give me a few more details like approximate times, temperatures, oil and coolant levels, leading up to when it happened I can pretty much tell you exactly how it happened.

regards


Darryl

[jfri]

Hi,

First of all, how long did you sit warming up for?

Next, did you wait until the Radiator Temperature was at 70C before openning up the throttle to full?.

Did you have the radiator fully open?.

Did you have the flaps down?

OR..you could have had a problem from an earlier flight, they Accusim aircraft are "persistant", that is, you get the aircraft in the same condition as you left it last flight.

If you give me a few more details like approximate times, temperatures, oil and coolant levels, leading up to when it happened I can pretty much tell you exactly how it happened.

regards


Darryl

What could it be? Maybe 15-30 seconds

No I dont think so

Yes

No

The plane was in god condition. Not even after the fire did I find anything to repair.

[CodyValkyrie]

Might not have even been on fire. It could have been the vent opening up to release pressure. Lastly, check you don't have auto mixture enabled.

[Killratio]

Agree with Cody, most likely a data corruption due to automixture enabled, unless it is radiator steam you are seeing, not smoke. .

However, if you are not waiting until the radiator temp reaches 70C in the Spit I before opening up, then you are not following the checklists and that is asking for trouble. You won't operate the Spit long term and healthy unless all of the proper procedures are followed.

Cold engine equals huge loads on the Merlin, huge as in "often fatal" within a few hours operation and within MINUTES if unlucky.

Oil Temp 15C and Radiator temp 70C as absolute minima for exceeding 1000-1200rpm. Add that to the hand pump on the undercarriage (and throw in a fixed pitch prop as well if you are realy game) and the Spit I is MUCH harder to operate within temps. A REAL chanllenge.

Oh and the Boost Guage..that is just how it is...off the end of the scale and maximum throttle will give you about 6 1/4 depending on engine health.

Darryl

[jfri]

Agree with Cody, most likely a data corruption due to automixture enabled, unless it is radiator steam you are seeing, not smoke. .

However, if you are not waiting until the radiator temp reaches 70C in the Spit I before opening up, then you are not following the checklists and that is asking for trouble. You won't operate the Spit long term and healthy unless all of the proper procedures are followed.

Cold engine equals huge loads on the Merlin, huge as in "often fatal" within a few hours operation and within MINUTES if unlucky.

Oil Temp 15C and Radiator temp 70C as absolute minima for exceeding 1000-1200rpm. Add that to the hand pump on the undercarriage (and throw in a fixed pitch prop as well if you are realy game) and the Spit I is MUCH harder to operate within temps. A REAL chanllenge.

Oh and the Boost Guage..that is just how it is...off the end of the scale and maximum throttle will give you about 6 1/4 depending on engine health.

Darryl

I don't have auto mixture enabled. Never had. And what I was seeing was not smoke but flames and only through the exhaust pipes(without smoke I think)
I have tried again and this time the plane didn't caught fire until just before takeoff when the radiator dial was mat maximum. Now the whole engine was on fire and my fps was down to 4 fps.
Regarding holding rpm below 1200 it's a little tricky. The gauge dial start at 1600 rpm.

[Killratio]

Flames "popping" in the exhaust stack is perfectly normal for the Merlin at certain rpm and times. It is a high powered, high performance engine.

As for the RPM, yes, the gauge only starts at 1600...just another little thing you need to learn to deal with flying the Spitfire. The Merlin will run "rough" at 600-800rpm and will "even out" by around 1000. You just have to set 1000-1200 by feel and by the sound of the engine. It is around half way between the bottom point of the gauge and the 1600 mark from memory..but to be honest I never really do more than glance at it to make sure it is not at the 1600 mark, the rest is just experience/judgement.

I would advise you to fly the Spitfire II until you get used to handling the Merlin. It is easier to handle after takeoff (powered undercarriage) and the minimum Radiator temp is 60C, giving you and extra 60 seconds or so on the ground.

Basically you need to begin your takeoff run at or before the radiator Temp gauge shows 100C or you will boil.

The fact that you are redlining the temp gauge just before takeoff tells me that you are either taxiing too far or taking too long with the preflight checks.

From startup to leaving the ground, you have around 8-10 minutes on a cool to medium temp day.

My checks go something like this after engine start for the Mk I with DH PCP airscrew:

1. Start Merlin and make sure it has "caught" by using primer and throttle. You will hear it surge a little and then settle.

2. Retard throttle to give 1000-1200rpm and confirm engine is running smoothly, turn on Generator, check temps and pressures. (5-10 seconds)

While engine warms

3. Set Altimeter, lock compass, set DG, turn on Pressure Head (Pitot Heat), (1 minute).

4. Check RPM, temps, pressures. (5 seconds)

5. Check Flaps, lower, confirm down with gauge and wing indicators, raise, confirm closed with gauge and wing indicators. (30 seconds)

6. Scan of all gauges and indicators (15 seconds)

Engine has now been running for around 2 minutes. Oil temp on a normal day should be around 30-40C easily. Now you just need to wait for the engine to warm....maybe another minute or three depending on ambient. (Let's say 2 minutes)

7. When Radiator temp reaches 70C open up to about 1800-1900rpm and change PCP to Full Fine Pitch (pull control all the way out), confirm increase in RPM... (5-10 seconds)

8. Go full throttle, check smooth running, 6 1/4 boost and then push in PCP control to "coarse", watch RPM drop, then pull control FULL out again. (15-30 Seconds)

9. At Full Fine and full throttle, check each mag in turn. (15 seconds).

10. Retard throttle to around 1000-1200 and clear area before beginning "S" turn taxi to runway...(10 seconds)

So by 5-6 miutes from start and at about 90C on the radiator you should be ready to taxi. This only gives you 10C to taxi and lineup....and at most 3-4 minutes to be off the ground, even on a cool day and if you have done your checks quickly and efficiently.

The Mk II takes an extra 15 seconds or so on the Airscrew checks but you have an extra 10C of radiator temp to play with after minimum.AND the power undercarriage means that you can take off at 110C at a pinch as the gear will be out of the way sooner.

Basically little margin for error or dallying.


Darryl

[jfri]

Flames "popping" in the exhaust stack is perfectly normal for the Merlin at certain rpm and times. It is a high powered, high performance engine.

As for the RPM, yes, the gauge only starts at 1600...just another little thing you need to learn to deal with flying the Spitfire. The Merlin will run "rough" at 600-800rpm and will "even out" by around 1000. You just have to set 1000-1200 by feel and by the sound of the engine. It is around half way between the bottom point of the gauge and the 1600 mark from memory..but to be honest I never really do more than glance at it to make sure it is not at the 1600 mark, the rest is just experience/judgement.

I would advise you to fly the Spitfire II until you get used to handling the Merlin. It is easier to handle after takeoff (powered undercarriage) and the minimum Radiator temp is 60C, giving you and extra 60 seconds or so on the ground.

Basically you need to begin your takeoff run at or before the radiator Temp gauge shows 100C or you will boil.

The fact that you are redlining the temp gauge just before takeoff tells me that you are either taxiing too far or taking too long with the preflight checks.

From startup to leaving the ground, you have around 8-10 minutes on a cool to medium temp day.

My checks go something like this after engine start for the Mk I with DH PCP airscrew:

1. Start Merlin and make sure it has "caught" by using primer and throttle. You will hear it surge a little and then settle.

2. Retard throttle to give 1000-1200rpm and confirm engine is running smoothly, turn on Generator, check temps and pressures. (5-10 seconds)

While engine warms

3. Set Altimeter, lock compass, set DG, turn on Pressure Head (Pitot Heat), (1 minute).

4. Check RPM, temps, pressures. (5 seconds)

5. Check Flaps, lower, confirm down with gauge and wing indicators, raise, confirm closed with gauge and wing indicators. (30 seconds)

6. Scan of all gauges and indicators (15 seconds)

Engine has now been running for around 2 minutes. Oil temp on a normal day should be around 30-40C easily. Now you just need to wait for the engine to warm....maybe another minute or three depending on ambient. (Let's say 2 minutes)

7. When Radiator temp reaches 70C open up to about 1800-1900rpm and change PCP to Full Fine Pitch (pull control all the way out), confirm increase in RPM... (5-10 seconds)

8. Go full throttle, check smooth running, 6 1/4 boost and then push in PCP control to "coarse", watch RPM drop, then pull control FULL out again. (15-30 Seconds)

9. At Full Fine and full throttle, check each mag in turn. (15 seconds).

10. Retard throttle to around 1000-1200 and clear area before beginning "S" turn taxi to runway...(10 seconds)

So by 5-6 miutes from start and at about 90C on the radiator you should be ready to taxi. This only gives you 10C to taxi and lineup....and at most 3-4 minutes to be off the ground, even on a cool day and if you have done your checks quickly and efficiently.

The Mk II takes an extra 15 seconds or so on the Airscrew checks but you have an extra 10C of radiator temp to play with after minimum.AND the power undercarriage means that you can take off at 110C at a pinch as the gear will be out of the way sooner.

Basically little margin for error or dallying.


Darryl

How can fire in an engine be normal ?

I have noticed that oil pressure and fuel pressure don't rise as high as expected according to the checklist. Still sometimes I have been able to takeoff.
Something I'm note sure I understand is that it sometimes seems impossible to engage the 'parking brake'. It engage and immediately disengage. Same result
when selecting wheel chokes which seem to automatically engage parking. Have this with both models. I have made one test flight with the MkII model.
One time I had wheel chokes applied and men sitting on the tail. I engaged max power and then when I pulled back the power I crashed and the display looked like I tipped over with the nose.
The canopy fog in partly even if I have windscreen deice on. Only solution I have is tom open the canopy but I expect I must have missed something.

[CodyValkyrie]

How can fire in an engine be normal ?

Not really an engine fire. It's just some flames coming from the exhausts. If you're seeing them coming from the exhausts, it could be overpriming or other factors. It may be alarming, but it happens often. Take a look at the 3:00 mark of the following video and you will see something similar:
https://www.youtube.com/watch?v=EWZj9F_9BTA

I have noticed that oil pressure and fuel pressure don't rise as high as expected according to the checklist.

The thing about the oil pressure is there is often a correlation between temperature and oil pressure, especially on a cold engine. On really cold days, the oil pressure could be quite high. Fuel pressure should be somewhat in the area. It doesn't have to be "exact," and those manuals were written a bit rigid (and later revised). It's advised to get those pressures as close as you can, but really what you are trying to do is warm up the oil a bit and ensure there are no major failures. Where you want to ensure everything is good is during the runup (make it fast and have it memorized). You can idle and keep her "somewhat" cooler, but the runup is where you are going to build up your temperatures quickly before takeoff.

Something I'm note sure I understand is that it sometimes seems impossible to engage the 'parking brake'. It engage and immediately disengage.

How are you engaging it?

One time I had wheel chokes applied and men sitting on the tail. I engaged max power and then when I pulled back the power I crashed and the display looked like I tipped over with the nose.

I can't recall if you want wheel chocks on during runup or not. Regardless, when doing a runup, make sure your stick is well back and make your power changes a bit slower. The baby spits are pretty bad about nosing over at very high power with brakes, which is all the more reason to keep that stick far back during any runup and taxiing.

The canopy fog in partly even if I have windscreen deice on. Only solution I have is tom open the canopy but I expect I must have missed something.

There is also a ventilation knob located just above the RPM gauge on the frame of the cockpit. Open that up if you need to, and it will help assist in keeping everything clear.

Keep in mind this is 1939 British technology. She's a thoroughbred, but has some interesting quirks, namely in how barely adequate the radiator is. Once you master this, you'll be flying like a real early Spitfire pilot. This is not an aircraft you can simply firewall (although there are some measures to keep the engine from completely blowing itself up). You treat her nice, watch the subtle ques and you'll have it down in time.

The manuals tend to be a bit wonky for the time, but that is period correct. It asks you to idle the aircraft for example at a low RPM, but there is no way to judge if this is correct or not. You have to idle her, watch the vibrations of the instruments and engine in order to find that sweet idling spot. Too low and she will look like she will start falling apart. Too high and you're going to heat her up quicker than you want. It takes some practice if you've never flown anything like this in FSX.

Last thing to think about, quick movements of the throttle will cause popping on the engine stacks. Move that throttle deliberately, but smoothly.

[Nixon]

Hi with regard to not being able to set the chocks and parking brake. I too have this problem and I overcome it by pulling out the USB connector for my CH rudder pedals. I have the same problem with the parking brake on the PMDG 737 NGX. Once I have done the run up I then plug my rudder pedals in. maybe worth a try.
Regards
Nixon

[Lewis - A2A]

Re: brakes, sounds like you may need dead zone as the brakes are set to on albeit slightly. Ive noticed that over time my ch pedals need this or the feet firmly on them making sure no brake pressure is dappled to the toe brakes.

thanks
Lewis

[CAPFlyer]

With the start video, I'm more alarmed by the way that guy treats the starter and engine than the flames. Starting with the exhausts upwind, cranking to the point the starter clutch pops loose, repeated short starts to high RPM, all bad things for any aero engine. Makes me cringe a little to see that.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

[jfri]

How can fire in an engine be normal ?

Not really an engine fire. It's just some flames coming from the exhausts. If you're seeing them coming from the exhausts, it could be overpriming or other factors. It may be alarming, but it happens often. Take a look at the 3:00 mark of the following video and you will see something similar:
https://www.youtube.com/watch?v=EWZj9F_9BTA

I have noticed that oil pressure and fuel pressure don't rise as high as expected according to the checklist.

The thing about the oil pressure is there is often a correlation between temperature and oil pressure, especially on a cold engine. On really cold days, the oil pressure could be quite high. Fuel pressure should be somewhat in the area. It doesn't have to be "exact," and those manuals were written a bit rigid (and later revised). It's advised to get those pressures as close as you can, but really what you are trying to do is warm up the oil a bit and ensure there are no major failures. Where you want to ensure everything is good is during the runup (make it fast and have it memorized). You can idle and keep her "somewhat" cooler, but the runup is where you are going to build up your temperatures quickly before takeoff.

Something I'm note sure I understand is that it sometimes seems impossible to engage the 'parking brake'. It engage and immediately disengage.

How are you engaging it?

One time I had wheel chokes applied and men sitting on the tail. I engaged max power and then when I pulled back the power I crashed and the display looked like I tipped over with the nose.

I can't recall if you want wheel chocks on during runup or not. Regardless, when doing a runup, make sure your stick is well back and make your power changes a bit slower. The baby spits are pretty bad about nosing over at very high power with brakes, which is all the more reason to keep that stick far back during any runup and taxiing.

The canopy fog in partly even if I have windscreen deice on. Only solution I have is tom open the canopy but I expect I must have missed something.

There is also a ventilation knob located just above the RPM gauge on the frame of the cockpit. Open that up if you need to, and it will help assist in keeping everything clear.

Keep in mind this is 1939 British technology. She's a thoroughbred, but has some interesting quirks, namely in how barely adequate the radiator is. Once you master this, you'll be flying like a real early Spitfire pilot. This is not an aircraft you can simply firewall (although there are some measures to keep the engine from completely blowing itself up). You treat her nice, watch the subtle ques and you'll have it down in time.

The manuals tend to be a bit wonky for the time, but that is period correct. It asks you to idle the aircraft for example at a low RPM, but there is no way to judge if this is correct or not. You have to idle her, watch the vibrations of the instruments and engine in order to find that sweet idling spot. Too low and she will look like she will start falling apart. Too high and you're going to heat her up quicker than you want. It takes some practice if you've never flown anything like this in FSX.

Last thing to think about, quick movements of the throttle will cause popping on the engine stacks. Move that throttle deliberately, but smoothly.

I engage the brakes with CTRL (or se wheel chokes). and sometimes it works. I tried adding a deadzone to my rudder pedal toe brakes and first it seemed to help but the problem has turned up again after that. Last time I noticed that after engaging the brakes I hear hissing sound when they immediately disengaged again (same thing happens when applying wheel chokes). The I could see I seem to need to fill more air again.

Another problem I have encountered while trying to learn this plane is a number of crash to desktop. Clearly more frequent than flying something different than the Spitfire.