Lean without audio clues? (and other questions)

[lowew79]

I just bought the T-6 for something a little different than the Cessna 182, boy was that goal EVER accomplished! I already feel like I've ruined the aircraft lol. I'm sure I will have a million questions as I go forward.

My first one is regarding the leaning process. The manual, and the forums speak of using the ear to lean the mixture, or leaning until the engine "loses power" then increasing again.

I have zero experience with real aircraft and really the only true engine sim I have is the A2A 182. So I don't know what a healthy 9 cylinder beast is supposed tp sound like. I know what I imagine it would sound like, and it hasn't sounded that way yet (my expectations were wrong). So leaning by ear is a strange concept before me. So I am trying to find a way to use the dials to lean, or at least check my lean.

So the manual speak of leaning until the engine "loses power". What does that mean lose power? RPM drop?, Manifold pressure drop?

On a side note, (and probably deserves its own topic, but its more of a observation) is this aircraft considered to be aerobatic? I notice in inverted flight the fuel seems to stop flowing to the engine, is that normal? What "cool" maneuvers are possible in this plane (I know I need to learn and practice a lot more before trying anything to fancy)? Are these aircraft just used at airshows to look beautiful at fly-by's? Or are they able to fly inverted the entire length of the airfield into an outside loop and the like?

Is it more preferable to land on two wheels or the three wheel landing?

[Piper_EEWL]

Hi,

First of all you did run the updater after installing the aircraft right? Because there have been quite some fixes published after the initial release. So that would be the first step.

Secondly as for leaning by ear. Go to your cruise altitude level of set the manifold pressure to 24" and the rpm to 1850. When the engine is stable start pulling the mixture back slowly and listen for a change in the sound. The rpm will start dropping slightly but the constant speed prop setup will counter that. So you have to watch and listen closely. Eventually you will reach the point where the engine will start to sputter. From this point on you'll have to move the mixture forward (towards rich) to reestablish power. That's how you lean by ear.

The other method would be to watch for EGT (Exhaust Gas Temperature). I never used it on the T6 since I usually lean that by ear but this is how it would be done with the C182. You start out with full rich and MP and rpm set as above. Now pull the mixture back a little and watch the EGT needle (it should rise since making the mixture more lean removes extra fuel from the combustion process and thus making it hotter). Wait till it stabilizes and the pull the mixture back some more. Wait till it stabilizes and so on. You'll reach the point where the EGT needle will start falling again. This point is called "Peak EGT" (here removing more fuel aka leaning will starve the combustion process of the necessary fuel so it'll get cooler from this point on). So now you have some options. Usually power settings are something like 50-125F rich of peak in modern aircraft engines. (I'm not sure about the radial in the T6!) Which means after determining peak EGT move the mixture lever towards rich till the EGT needle stabilizes at about 50F below the peak EGT. (Usually one increment on the EGT scale equals 25F). Remember that the EGT is a relative temperature. That's why there is no numbers on that EGT scale.

That's a lot to take in for now I think See how far this takes you and if you have more questions there is some great threads on the forums here about this.

I hope this helps for a start though.

As for aerobatics. The T6 cannot do extended inverted flight (same goes for the P-51 or the Spitfire btw) because the lubrication system and the fuel feed won't work meaning the engine will either starve of fuel or sneeze up due to a lack of oilpressure. So it's "only" positive g-maneuvers like loops, rolls it can even do a snap roll. It's quite hard to master those so I think you'll have a lot of fun with it.

And last but not least I would start out with two wheel landings as I find it easier to control the plane after touch down this way.

Happy flying

[AKar]

With T-6, as you lack the EGT indication, you need to lean by ear: there is a hint of roughness in the engine that you can listen for in the simulation. But I wouldn't expect very noticeable uneven running, because the impeller distributes the mixture quite evenly. But you still feel how the engine starts to lose power as you bring the mixture back. As mentioned, it is not immediately shown on any of the gauges: manifold pressure is of course unaffected, and RPM is held more or less constant by the governor.

-Esa

[Piper_EEWL]

With T-6, as you lack the EGT indication, you need to lean by ear.

oops. Funny how I haven't even noticed that since I almost only lean by ear in A2A planes nowadays. But once again a classic case of "look at the instrument panel before giving a long speech about leaning by EGT"

[lowew79]

I own the 182. I didn't appreciate how easy that aircraft is to fly until I tried my hand at this T-6. Well, that's not fair, regular straight and level flight is pretty easy in the T-6, which is pretty much all you CAN do in the 182.

Point being I am aware of using the EGT method, in fact I apparently have spoiled by it as I am not getting the trick of doing it any other way lol. The engine on the T-6 seems to have a constant, rhythmic, but subtle thump-thump-thump noise, I think I'm hearing that and mistaking it for roughness, when that may just be the regular engine noise for this aircraft. I can hear the sputtering you speak of though, like a if I was listening to record of a engine noise and it was skipping. That's way far back on the mixture axis for me.

Question is, once I hear the sputtering, how far do I push the knob back in? Just until it runs smooth again? A little bit more than that to be rich of peak?

I know form owning the 182 that spark plug fouling is the sign of poor mixture. But I can't keep from crashing the T-6 long enough to foul a plug (aerobatics lol). I need to find information on how to practice aerobatics safely, but that's another post!

Are two-wheel landings the preferred method when the runway is long enough? That tail wheel seems so fragile to be landing on.

With T-6, as you lack the EGT indication, you need to lean by ear: there is a hint of roughness in the engine that you can listen for in the simulation. But I wouldn't expect very noticeable uneven running, because the impeller distributes the mixture quite evenly. But you still feel how the engine starts to lose power as you bring the mixture back. As mentioned, it is not immediately shown on any of the gauges: manifold pressure is of course unaffected, and RPM is held more or less constant by the governor.

-Esa

I guess I don't get what you mean by FEEL the engine losing power? Sitting at a computer, I have my eyes and ears I can't feel deceleration or anything. I'm not trying to be smart with you, I really truly don't know what you mean by "feel". Are saying I have to listen for the change, but that the change will be subtle?

Finally, I know you guys are trying to help, and I am trying to implement what you are saying, heck, maybe I'm doing it right and just over thinking it lol! I appreciate the replies (AKar, a special thanks to you as you've helped me numerous times on this forum)

[Piper_EEWL]

Question is, once I hear the sputtering, how far do I push the knob back in? Just until it runs smooth again? A little bit more than that to be rich of peak?

Well that's good that you hear that . If you get sputtering I would push the mixture to more lean till the engine runs smoothly and then a little bit more to be on the safe side.

I know form owning the 182 that spark plug fouling is the sign of poor mixture. But I can't keep from crashing the T-6 long enough to foul a plug (aerobatics lol). I need to find information on how to practice aerobatics safely, but that's another post!

You might want to search the forums a bit there are some tips from Dudley Henriques around on how to loop the T-6 and other basic aerobatics. Great posts and definetly worth reading!

Are two-wheel landings the preferred method when the runway is long enough? That tail wheel seems so fragile to be landing on.

The tailwheel is not to fragile to land on. But if you touch down in a three point attitude I find it a bit more difficult to keep tha plane from ground looping. When the runway is long enough I usually do a two wheel landing and then let the tail settle onto the runway.

I guess I don't get what you mean by FEEL the engine losing power? Sitting at a computer, I have my eyes and ears I can't feel deceleration or anything. I'm not trying to be smart with you, I really truly don't know what you mean by "feel". Are saying I have to listen for the change, but that the change will be subtle?

When you can tell the plane is decelerating you've gone to far. If you watch the rpm gauge closely while you pull the mixture back you can tell that at one point it'll start dropping a bit, then coming back up dropping again and so on. It's not the sputtering it's way more subtle. At that point the noise of the engine also changes. I guess that's what Esa means by "feeling" the engine loosing power. Once you've noticed that point you'll be able to identify it more easily the next time. Give it a try in smooth weather and maybe while flying level with the autopilot so you have time to focus on the engine.

[AKar]

Yes, and being careful, one can actually feel the power loss in the simulator too: airplane reacts like it would to any slight power reduction.

-Esa