Board index Other Hangar talk Real aviation

Searching for experience with spark plug fouling

The "real" thing.
Forum rules
Please refrain from discussing politics.

Searching for experience with spark plug fouling

Postby benih » Wed Sep 22, 2021 7:21 am

Hi there, the past days I assembled some information to implement Spark plug fouling at the C182s (which I plan to be portable to the default C172p).
I already know the factors leading to it and how to remedy, and there is also alot of videos showing fouled spark plugs and the behaviour of engines suffering it.

What i don't know, however is:
- how common is this?
- how fast does fouling develop usually (in minutes)?
- Is it easy to trigger, or is it a thing occuring by chance (ie. when idling at the stand for, say 10 minutes at 800rpm at an average day, is it by pure luck to foul a plug? or can you reliably trigger this?)
- How much of a factor is OAT, (I think it should be great, because the plugs are starting colder?)

In short: I need some real world expertise to implement the effect, especially the tripping part.


Thank you in advance :)
User avatar
benih
 
Posts: 976
Joined: Tue Aug 15, 2017 9:34 am
Callsign: D-EBHX
Version: next
OS: Debian Linux 64bit

Re: Searching for experience with spark plug fouling

Postby benih » Sat Oct 09, 2021 11:25 am

Just an update.
I found more information on the subject and started developing the underlying systems for the simulation. Currently it works on the left magneto, but adding it for both is trivial. I just need to finish die minor things and then will upload the branch ad pull request for broader Testing.

I *think * (aka hope) the numbers are roughly in the right spot but from what I have read, I can see the expected effects.

What’s needed now is some real world experience to fine tune.
User avatar
benih
 
Posts: 976
Joined: Tue Aug 15, 2017 9:34 am
Callsign: D-EBHX
Version: next
OS: Debian Linux 64bit

Re: Searching for experience with spark plug fouling

Postby V12 » Sun Oct 10, 2021 7:51 pm

In the car engine - I made on one set of the spark plugs 60k kilometers without any missfire. It is 5 cylinder turbocharged Volvo T5 engine in the Ford Mondeo 2008.
Fly high, fly fast - fly Concorde !
User avatar
V12
 
Posts: 2521
Joined: Thu Jan 12, 2017 4:27 pm
Location: LZIB
Callsign: BAWV12

Re: Searching for experience with spark plug fouling

Postby benih » Sun Oct 10, 2021 8:46 pm

Cars != Airplanes.
Cars use unleaded fuel for example…
User avatar
benih
 
Posts: 976
Joined: Tue Aug 15, 2017 9:34 am
Callsign: D-EBHX
Version: next
OS: Debian Linux 64bit

Re: Searching for experience with spark plug fouling

Postby V12 » Mon Oct 11, 2021 7:01 am

Fly high, fly fast - fly Concorde !
User avatar
V12
 
Posts: 2521
Joined: Thu Jan 12, 2017 4:27 pm
Location: LZIB
Callsign: BAWV12

Re: Searching for experience with spark plug fouling

Postby benih » Mon Oct 11, 2021 8:04 am

Thank you very much for the interesting read! :)

I think that means that we need an option to distinguish the used fuel in the plane in the fuel dialog, and if UL fuel is used, lead fouling is to be disabled internally.
However, I think that carbon fouling by using overly rich mixture still will be an issue to be simulated (being full rich at high airports for example, or cruising full rich).

Edit: OTOH its not yet there approved for the C182S from 1996.
User avatar
benih
 
Posts: 976
Joined: Tue Aug 15, 2017 9:34 am
Callsign: D-EBHX
Version: next
OS: Debian Linux 64bit

Re: Searching for experience with spark plug fouling

Postby TheEagle » Sat Oct 16, 2021 5:38 pm

Wait - are you telling me one can choose the fuel in the C182 in FG :o ? Or did I get something wrong ? :oops:
User avatar
TheEagle
 
Posts: 768
Joined: Sat May 01, 2021 2:27 pm
Location: France
Callsign: F-EAGLE
IRC name: none
Version: 2020.4.0
OS: Ubuntu Studio 20.04

Re: Searching for experience with spark plug fouling

Postby benih » Sun Oct 17, 2021 8:57 am

Not yet. It’s currently fixed to AVGAS100LL.
But if UL is approved for the engine, we might add an option to change it.
User avatar
benih
 
Posts: 976
Joined: Tue Aug 15, 2017 9:34 am
Callsign: D-EBHX
Version: next
OS: Debian Linux 64bit

Re: Searching for experience with spark plug fouling

Postby benih » Sun Oct 17, 2021 10:12 am

benih wrote in Sat Oct 16, 2021 5:08 pm:That is true S&J, but for the magnitude of the effect there is footage online.
The time and conditions for resolving are well known, too.
What I don’t yet have found is the time it takes to foul a plug given the right conditions. I tried to encode the vague reports from real aviation forums into something usable and decided for about 10 minutes (give or take).

If you have something valuable to add in those redirects, you are more than welcome to post it here: viewtopic.php?f=34&t=39770


To elaborate a little:
  • I have read that fouling can happen when idling too long at parking without proper rpm/leaning. I think that can only mean when we actually want to fly and running trough our checklist and prepare the flight, setting radios, looking up stuff on the map, and especially waiting for taxi clearance.
    I.e.: we are not talking hours here, but quarters.
  • Also I have read that this can happen in big airports where you have to Taxi long ways. The c182 checklist says, we are to be full rich at landing and if you forget to relean to taxi, you are bound to be operating full-rich and idle rpm (or wear down your brakes).
    Hence we are talking not about half an hour but the timeframe of several minutes here.

In conclusion I think the simulation is already „ok“, however i would prefer to make it even better.
For this I need sind reports telling me something along the line „it did happen to me after 10 minutes of taxi at eddm“.
User avatar
benih
 
Posts: 976
Joined: Tue Aug 15, 2017 9:34 am
Callsign: D-EBHX
Version: next
OS: Debian Linux 64bit

Re: Searching for experience with spark plug fouling

Postby wlbragg » Sun Oct 17, 2021 3:19 pm

You sound like you already have a really good handle on it.
There are a few variables that would logically influence the timing of this.
We know fuel is one of them, I would submit even the same type or brand of fuel from day to day could influence this, different qualities of the same fuel source.
Age of the fuel in your tank.
How much water (if any) is in the fuel.
Maybe average humidity at the location you fly most?
Average pressure you fly at?
Add to that the many ways you can run your engine out of specks that you previously wrote about, long idle, checks, etc.
Then there are actual mechanical, issues, timing, carburation, etc., that can be real big culprits. I've had some experience with that in the day working on motorcycle engines.

What I am saying is you may not be able to get anything more definitive because of all the variables.

If you could determine what, if any, environmental conditions, mechanical conditions, age, tune-ups might be an influence on any particular aircraft and user in the sim, maybe you could use that information to also randomize the frequency or likely hood of fowling.

Example, we have walk through checks, and fuel check simulations in our aircraft, if using the GUI mode that uses the real life simulation stuff, then randomize hi and low percentages of your normal fowling checks with the results of doing or not doing those checks. More likely the less maintenance you perform the higher the likelihood of fowling if you idle too long at the wrong mix or any of the other conditions you mentioned.
Kansas(2-27-15)/Ohio/Midwest scenery development.
KEQA (2-27-15), 3AU, KRCP Airport Layout
Intel i5 3570K AMDRX480
wlbragg
 
Posts: 6274
Joined: Sat Aug 25, 2012 11:31 pm
Location: Kansas (Tornado Alley), USA
Callsign: WC2020
Version: next
OS: Win10/Linux/AMDRX480


Return to Real aviation

Who is online

Users browsing this forum: No registered users and 1 guest