C421C advanced physics: the real stuff for OEI training

[onduty 5]

Hi Andi,

I was away from this forum for a couple of days and try to ketch up again.

1. Please confirm, your modified air and cfg files are for p3d and will not work in fsx?

2. Do I understand well that you abandoned the attempt to put the takeoff/ climb fuel flow right?

Tamas

 

[AndiKunzi 62]

11 hours ago, onduty said:

Hi Andi,

I was away from this forum for a couple of days and try to ketch up again.

1. Please confirm, your modified air and cfg files are for p3d and will not work in fsx?

2. Do I understand well that you abandoned the attempt to put the takeoff/ climb fuel flow right?

Tamas

 

Hello Tamas,

1. I‘m not sure how those files will work in FSX. Basically, they should.

2. T/O and climb FF have slightly improved, as a side effect of engine efficiency and reaistance, IIRC. Correct FF would need an aircraft modification not using the leaning algorithm within MS ESP / Flight Simulator or constantly modifying the engine parameters. I am sure that Lockheed Martin could do that in a smarter way in the main simulation engine with relatively small effort, but for us it would be a major alteration either by having algorithms within the aircraft constantly adjusting engine parameters or by modifying the source code of P3D. 

I hoped on Lockheed Martin (and still do). Maybe one day I‘ll be bored and try to see if I could program a leaning correction using the Prepar3D SDK.

If somebody who is already familiar with the P3D SDK should read these lines, I would be happy to discuss the feasability of reading the relevant variables (Mixture position, air-fuel-ratio, pressure altitude, temperature, manifold pressure, RPM, FF, power output, ...) and writing the necessary ones for correction (air-fuel-ratio, engine efficiency, prop efficiency, perhaps power output and probably some others). Another approach could be writing a gauge.

Maybe FSDeveloper would be the right place to get a quick start approaching the problem.

Edited June 10, 2018 by AndiKunzi

[zazaboeing 15]

Hi Andi, how are you?

Thanks for all the efforts done so far!

Well, I've testing your mods, and Engine Out performance seem rather nice now, the only problems I see are:

1. You cannot obtain full RPM when applying FULL POWER in initial takeoff roll, it will only go to FULL RPM at +- 60kts.

2. When restarting the dead engine (after an intentional cut for training purposes), even well above VMCA, after the engine fires, the plane goes completely crazy, getting out of control in a kind of CLIMBING spin jumping to more than 100000ft 😱, and the propellers are lost! Never seen this before! (Attached picture)

 

Regarding the FF/Engine Output in ESP limitations, I'm really willing to help you or anyone providing real world data and tests, but I doubt LM would fix it. It's a "cancer" that's been in FS world since decades, so unrealistic! The absurd exagerated leaning to generate power is tremendous, and you have to do it to even continue on climb on aspirated and turbo engines, reducing the mixture to increase your Fuel Flow (!!!). By reaching 25000 with the 421C for example, you're almost cutting the mixtures.

The only planes I've seen to work flawlessly are the A2A ones, correct mixture and propeller, FF and power output all the way up. Maybe because they use some external trick or something in the model that simply overcomes these issues.

 

Thanks for the mods anyway!

 

PS: I've not find it in the manuals, but can you tell us what is the Maximum Continuous Power in the 421c, in case of an engine failure? 32.5/1900?

Edited June 10, 2018 by zazaboeing
Pic

[AndiKunzi 62]

9 hours ago, zazaboeing said:

Hi Andi, how are you?

Thanks for all the efforts done so far!

Well, I've testing your mods, and Engine Out performance seem rather nice now, the only problems I see are:

1. You cannot obtain full RPM when applying FULL POWER in initial takeoff roll, it will only go to FULL RPM at +- 60kts.

2. When restarting the dead engine (after an intentional cut for training purposes), even well above VMCA, after the engine fires, the plane goes completely crazy, getting out of control in a kind of CLIMBING spin jumping to more than 100000ft 😱, and the propellers are lost! Never seen this before! (Attached picture)

 

Regarding the FF/Engine Output in ESP limitations, I'm really willing to help you or anyone providing real world data and tests, but I doubt LM would fix it. It's a "cancer" that's been in FS world since decades, so unrealistic! The absurd exagerated leaning to generate power is tremendous, and you have to do it to even continue on climb on aspirated and turbo engines, reducing the mixture to increase your Fuel Flow (!!!). By reaching 25000 with the 421C for example, you're almost cutting the mixtures.

The only planes I've seen to work flawlessly are the A2A ones, correct mixture and propeller, FF and power output all the way up. Maybe because they use some external trick or something in the model that simply overcomes these issues.

 

Thanks for the mods anyway!

 

PS: I've not find it in the manuals, but can you tell us what is the Maximum Continuous Power in the 421c, in case of an engine failure? 32.5/1900?

Hello Zaza,

1. RPM low below 60 KIAS:

I know the issue with the RPM being low below 60 KIAS. I didn't focus on that since for all flying issues, you are above 60 KIAS. Cause: I put in the right propeller size but did not finish the adaption of the power curves for very low speed. On my not published C421 based on the C404 Titan mod, I didn't care about prop size in the aircraft.cfg being wrong so I left the prop size at 6.7 ft. But since I know that you guys would find the setiing in the aircraft.cfg and complain, I started the adaptions using the correct prop size: 7.6 ft. Quite impressive for a piston twin when someone is normally flying a C172. I'll work on that for the Alabeo C421C advanced physics. Should not be a big problem (but might need another data row for 5 deg prop AOA).

Consider it as a real world behaviour: your mechanic set the fine pitch limit too conservatively. By experience, I can tell you that can happen. You found the fault, which in real live would cost you a few feet of take-off distance. Your mechanic has a ticket now, but shops are crowded, as usual...

 

2. Losing the prop:

The reason is how the sim starts the engine using CTRL + E. This will bring the prop from feather to full fine within milliseconds. Given the high TAS at altitude, you'll overstress engine and prop - in the sim as well as in the real aircraft (at lower altitudes, at least the sim won't be harmed).

During Air Start in a real MEP twin, the oil pressure is building up, pushing the prop from feather to finer pitch within about 2 to 3 seconds. While that, you retard the prop lever to avoid high RPMs at all. Never let the engine go to high RPM during air start immediately. Never! And never do that in the sim. Don't use CTRL + E, use the real buttons and medium prop position or retard immediately after firing and everything will be fine. As in the real aircraft.

If you use CTRL + E, this is overriding the Prop Lever on your Throttle Quadrant - if you retard the prop immediately after firing, everything will be smooth, even with CTRL + E. However, I do encourage using the checklist for air start (and before that: for shutting down) and the correct buttons for training purposes. You might forget setting the fuel selector back to on, or the magnetos. You'll be in panic in a real emergency unleess you are Chuck Yeager of Bob Hoover. So I really like to train with the real buttons. For working on checklists just to the point before pressing the starter, you may use the autopilot - on the sim as well as in reality.

Edited June 11, 2018 by AndiKunzi

[AndiKunzi 62]

RPM below 60 KIAS is solved.
New mods in "modifications advanced physics c421.air" are ready for download.

[zazaboeing 15]

On 6/11/2018 at 5:52 AM, AndiKunzi said:

2. Losing the prop:

The reason is how the sim starts the engine using CTRL + E. This will bring the prop from feather to full fine within milliseconds. Given the high TAS at altitude, you'll overstress engine and prop - in the sim as well as in the real aircraft (at lower altitudes, at least the sim won't be harmed).

During Air Start in a real MEP twin, the oil pressure is building up, pushing the prop from feather to finer pitch within about 2 to 3 seconds. While that, you retard the prop lever to avoid high RPMs at all. Never let the engine go to high RPM during air start immediately. Never! And never do that in the sim. Don't use CTRL + E, use the real buttons and medium prop position or retard immediately after firing and everything will be fine. As in the real aircraft.

If you use CTRL + E, this is overriding the Prop Lever on your Throttle Quadrant - if you retard the prop immediately after firing, everything will be smooth, even with CTRL + E. However, I do encourage using the checklist for air start (and before that: for shutting down) and the correct buttons for training purposes. You might forget setting the fuel selector back to on, or the magnetos. You'll be in panic in a real emergency unleess you are Chuck Yeager of Bob Hoover. So I really like to train with the real buttons. For working on checklists just to the point before pressing the starter, you may use the autopilot - on the sim as well as in reality.

Hi Andi! Thanks for the reply and later fix, I’ll try it as soon as I get back home in a few days.

Regarding the airstart, I’ve never used Ctrl+E, and I don’t recall having to restart any engine I’ve operated in real life with the propellers levers other than full foward, but, bear in mind I’ve never operated a geared engine and I don’t have the 421 manual to check.

BTW, VEEEEEEERY nice panel you have on your RW 421C. I wish some day we can get that kind of avionics upgrades in sim as well.

Best regards,

Rafael Zaza

[AndiKunzi 62]

Hello Zaza,

Air Start as per authorized AFM / POH:

Cessna 421C and C340A: Prop forward of detent (that is just out of feather)
Piper Seneca II and III: Prop forward to cruise RPM

Both AFM / POH: reduced power until engine is warm.

Which aircraft did you use for your MEP?
I know that some instructors use prop full forward for air start without immediately retarding - because they don't read manuals. The fast spin-up is painful to feel, hear and see for an engineer...

Regarding the panel in N100L:
I'd really love to have that, at least the Aspen. On the Aspen, you set Altitude Bug (and thus, control Altitude Preselect), Speed Bug, Minima (DA / MDA), GPS Steering - and you have a clear Flight Director together with wind vector, OAT and an HSI with moving map and waypoint info.  

Edited June 12, 2018 by AndiKunzi

[zazaboeing 15]

You’re right, in the Piper Chieftains we used mid position on the props for airstart.

I’ve flown Senecas (2 and 5), 310, Baron and Piper Navajos as multi engines aircrafts, but that’s 14 years a go so my memory might trick me well. I don’t have many levers to bother now, and airstarts are pretty easier lol

[AndiKunzi 62]

C310 might be oldschool full forward...
I'd tend to say that not your memory is tricking you, but your instructor was - at least on the Seneca.

What are you RW flying now?

Edited June 12, 2018 by AndiKunzi

[RobertBernardK 7]

20 hours ago, AndiKunzi said:

RPM below 60 KIAS is solved.
New mods in "modifications advanced physics c421.air" are ready for download.

There are new mods in the folder?  I don't see differences in the size of the folder. 

Thanks In advance 

RB

[zazaboeing 15]

3 hours ago, AndiKunzi said:

C310 might be oldschool full forward...
I'd tend to say that not your memory is tricking you, but your instructor was - at least on the Seneca.

What are you RW flying now?

737 Andi

[AndiKunzi 62]

24 minutes ago, RobertBernardK said:

There are new mods in the folder?  I don't see differences in the size of the folder. 

Thanks In advance 

RB

Sorry, Robert!
I forgot to synchronize my folders.
Should be OK now, only the .air was updated.

[AndiKunzi 62]

New "modifications advanced physics aircraft.cfg" is available for download.

Changes:
- pitot heat
- gear warning with throttle and flaps up

[Fearless 6]

Hmm, Where can I get the AirEd utility from?  I run FSX

[Fearless 6]

Well team,

Cudos for the mod but I’m having a awefull time getting up to desired FL and cannot get the power I’m up 100% throttle,  mixture at at 20% and hovering at 90-100kts IAS.

Then, all of a sudden I hear increased pitch sound and IAS increases to a more acceptable level.

To bring the manifold pressure into the green zone, throttle is at 82% drops the IAS back to 110kts way out of the green zone.

What am I missing or doing wrong?

 I found the AirEd for downloading by the way.

Thanks in advance.

Edited May 9, 2019 by Fearless