help a pleb like me with sparkplugs

[bliksimpie]

I have read through the accusim manual and understand all principles but I dont see anything mentioned about conserving the spark plugs..

I need help on how to fly it to prolong the spark plugs. Dont know what I am doing wrong but I have the spark plugs foul very quickly and I am having this maintenance guy that is all over me after a flight about them needing to replace sparkplugs..! Unfortuanterly I cannot fire the guy but I really need to bypass him as much as possible as he write damning reports to my chief in command.

Please help !!

BTW absolute brilliant plane..!!

[CodyValkyrie]

The spark plugs will foul if you are idling your throttle. The manual states in the quick flying tips the following:

Keep your engine at or above 800 RPM Failure to do so may cause spark plug fouling. If your plugs do foul (the engine will sound rough), try running the engine at higher RPM. You have a good chance of blowing them clear within a few seconds by doing so. If that doesn't work, you may have to shut down and visit the maintenance hangar. (Accu-sim required)

Since your RPM gauge doesn't go that low, I generally raise RPM until I see movement on the RPM gauge (with brakes applied of course), then slowly back the throttle of a bit. If it sounds rough, I advance throttle. It takes a bit of practice.

Please note that Accu-Sim accounts for oil viscosity as well. If you raise your RPM too high while warming up and trying to keep your plugs from fouling, you could risk doing damage to your oil lines, etc. Keep an eye on your oil pressure as well while your oil is warming up.

[Killratio]

You need to keep your revs above about 1100, 1200 at ALL times to keep the sparkplugs clean. You can try to lean the mixture to get them clean but the best option is to run at a very high power setting for a minute.

Darryl


Cheers Cody, beat me to it. 800 will keep the plugs cleaninsh but causes a couple of other problems due to rough running. You pay's your money and takes your chances...

[lonewulf47]

And don't forget: we're talking about AccuSim - you HEAR when the engine is running clean ! Just increase the throttle a bit after engine start and listen to the sound. You will notice that the sound will turn into a crisp clean rumbel when you're at the proper idle revs. Those days tjhe pilotsa did not need a perfect RPM gauge and pefect numbers. They needed perfect ears..

Oskar

[DHenriques_]

The spark plugs will foul if you are idling your throttle. The manual states in the quick flying tips the following:

Keep your engine at or above 800 RPM Failure to do so may cause spark plug fouling. If your plugs do foul (the engine will sound rough), try running the engine at higher RPM. You have a good chance of blowing them clear within a few seconds by doing so. If that doesn't work, you may have to shut down and visit the maintenance hangar. (Accu-sim required)

Since your RPM gauge doesn't go that low, I generally raise RPM until I see movement on the RPM gauge (with brakes applied of course), then slowly back the throttle of a bit. If it sounds rough, I advance throttle. It takes a bit of practice.

Please note that Accu-Sim accounts for oil viscosity as well. If you raise your RPM too high while warming up and trying to keep your plugs from fouling, you could risk doing damage to your oil lines, etc. Keep an eye on your oil pressure as well while your oil is warming up.

The general rule in flying these prop fighters is that power keeps the plugs clean. With a Merlin, rather than burning them clean with mixture reduction, the better way is to blast them clean with a shot of power.
On the ground it's tricky as you don't want to be using any excess power than needed to keep the taxi speed down, so just before takeoff, I always gave the engine some throttle as I took position to roll. This coupled with takeoff power cleans you up fairly fast as you take off.
In flight, the Merlin usually runs clean. Landings are usually where the Merlin newbie gets into fouling issues trying to slow down the aircraft by prolonged power reduction. Try to plan your arrivals so that you are in the area of 200mph or a bit less approaching the field. Use drag in turns to slow you down and keep the power up around 20 to 22 inches to keep the engine clean. If you do get plug fouling, AFTER you run up the prop in the approach, give the engine a shot of power to clear the plugs.
As with all things related to flying these high performance prop fighters, proper planning as relates to power use and airspeed control is the key.
The cardinal rule with a Merlin is don't get yourself caught back in a corner on an approach where you need to use prolonged idle power to lose altitude or airspeed or both.
PLAN AHEAD!!
Dudley Henriques

[Bomber_12th]

You will often times see a piston powered aircraft run up for 30-sec to a minute before shut down, which in my understanding helps clean the plugs and get fresh oil circulating before the engine is put to bed. When done in a Spitfire, this is one of those times when a two-three person crew is required to come over and hold the tail down. I would imagine with Accu-sim, this would be worthwhile to do. If you are already running too hot, there isn't much chance of accomplishing this, so an immediate shut-down is all that can be done - next flight you will just have to make sure you run all the pre-takeoff checks (as always), especially the ever important mag check, to ensure everything is healthy.

-If I recall correctly, I have only ever seen this done on late-mark Spitfires, so perhaps the Mk.I/Mk.II, with their cooling issues, aren't too capable of this - though I did do a 30-sec ground run before shut-down on my second flight in the Accu-sim Spit, and it performed just fine, with no overheating - I was extra cautious about coolant temp though throughout the approach, overhead break, and landing.

[Killratio]

And PLAN AHEAD works ON the ground after landing too.

Turn OFF both fuel cocks about the time you do the Flaps up and radiator Shutter open. That way by the time you have taxiied in, she will be ready for the SRCO to be pulled.

The engine is best idled at just above rough running once stopped. Any attempt to run it up against the brakes will lead to an overheat in seconds.

Darryl

[bliksimpie]

Thanks guys for the great tips.

I must say it is MUCH better now. My main problem I think was that I let it run too long at idle espesially at comming in for landing I was pulling power way down to reduce airspreed.

As they aid above you need to plan ahead and so far i have not had to visit the maintenance hanger.

Absolute brilliant plane.

[lawdawg]

Brilliant workmanship/plane indeed.