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PostPosted: Sun Jun 03, 2012 8:41 pm 
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I read comments regarding slowing down the p51 with 25 inches and full fine prop. However, even with flaps 20 and 0 vertical speed, the speed just doesn't bleed off. Getting down to gear down speed 170kts is thus a challenge for me. I pretty much have to go gear down to get the drag needed to slow down for full flaps, 165kts.

And landing seems to be a bumpy affair, I seem to bounce even when coming down real smooth, nearly 0ft/min, at near 120kts, for a lightly loaded plane.

What proper technique do I need to follow to slow her down?


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PostPosted: Sun Jun 03, 2012 8:55 pm 
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You can go below 25" to reduce speed on the approach.
It's not good to stay low on MP setting all the way down, so as soon as you drop the gear and the first notch of flaps, you power up a little bit to mantain 170kts for the approach and to save your spark plugs. :D


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PostPosted: Sun Jun 03, 2012 8:57 pm 
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If you are too high, then you won't lose speed very quickly without your engine at idle, and that will foul your plugs. If too high on the approach, a forward slip, or side slip will help you descend, and kill airspeed.

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PostPosted: Sun Jun 03, 2012 9:34 pm 
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This is one reason why the fighter break is such an important move. It helps bleed off any excess speed. Fly the runway heading and break off into a turning climb while dropping a bit of flaps. Usually once you're out of the break you should be close enough to the speed to start worrying about the landing gear.

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PostPosted: Sun Jun 03, 2012 10:52 pm 
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CodyValkyrie wrote:
Fly the runway heading and break off into a turning climb while dropping a bit of flaps.

How much is a bit of flaps? Do i drop them 10 or 20 degrees?

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PostPosted: Sun Jun 03, 2012 10:54 pm 
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You can drop 10 flaps up to 400 MPH, which is generally what I do.

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PostPosted: Mon Jun 04, 2012 12:07 am 
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thanks for the advice, slipping helped a little but seems cutting the throttle down to near idle w/ buzzer going seems to slow her down a lot. have to cycle the throttle up to keep the plugs from fouling but combination of everyone's suggestion delivered a controlled approach speed.


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PostPosted: Mon Jun 04, 2012 2:47 am 
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The Mustang needs a bit more of pre-planning for the landing phase just because its aerodynamics are quite fine-tuned. A fighter-break is one possibility to reduce speed due to increased drag but there's also the simple method of using flaps which has gone forgotten to a certain extent as in many WWII era aircraft flaps are not really used to slow down an A/C but to keep the speed low once it is reached e.g. the Spit with its spread-type flaps with rather low Vfe. With the Mustang however you really can and should use flaps for slowing down. If you look at the placard at the right canopy rail you can easily see that up to flaps 20° can be used at 275 MPH IAS which gives you a considerable drag increase. Nevertheless it is also adviseable to descend early with low enough power and fly a few miles level while gradually reducing speed just by letting it drop due to the lower power and then closing in to the pattern by using flaps up to 20° and decreased prop pitch (2700 RPM), which also helps some more before dropping the gear.

You will notice that after some practice this is a very convenient method and applicable to any airport pattern where a fighter break is not the first means to reduce speed (try this in a busy General Aviation pattern full of Cherokees and Skyhawks... :wink: )

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PostPosted: Mon Jun 04, 2012 3:24 am 
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You know one of the things that I find very interesting about simming is how closely the various 'simming styles' correlate so well to the real-world experiences and styles of pilots. I'm 90% Airliner Sim guy, and, perhaps to my detriment, am always thinking about minimum maneuver speeds for a given flap setting. It bothers me when I don't have Speed Cards! So while I'm not worth a damn flying acrobatics or anything like that I tend to do very well with hitting pattern speeds and altitude targets. Anticipating the decelerations is no prob for me because I'm so used to flying all those simulated big jets. On the other hand, I have mediocre landings in these tail-dragging piston planes, typically, because there is always a little voice in the back of my head telling me to 'plant' the aircraft into the pavement at 150 fpm. I guess this is testament to just how accurate simulate airplanes have become these days, because I've read many stories of real pilots that have the same troubles! It takes a real conscious effort on my part to transition my mind from flying something like the pmdg 737 to the A2A P40 or P51, all of them highly accurate renditions of their respective genre.

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PostPosted: Mon Jun 04, 2012 11:04 am 
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Hello dear friends,

In first excuse for my poor English...

I found this conversation very interesting because the P-51 is one aiplane very aerodynamic and it's true that it's not easy to loose the speed before the approach.
During the approach phase with my P-51, my MP is 25" and my Prop Pitch 2700 RPM.

With this motor's setting my spark plugs do not suffering too ?

Please can you tell me if it's good to have my Prop Pitch at 2700 RPM for the approach or it's the good RPM ?
For my approach and with 2700 RPM, can you tell me the maximum MP that I can stay at 25" or up or below ?

And I always the approach must use the oil dilution ?

I would like to thank you for your help, best regards. Olivier

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PostPosted: Mon Jun 04, 2012 1:43 pm 
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I saw an interesting way to slow down this weekend: The CAF Dixie Wing's P-51 Red Nose finished up its demo, then overflew the field while climbing into a slow roll. At the top of the roll the pilot started to extend the gear, and it was down by the time he was level. He then entered the pattern and promptly landed. As soon as he was on the taxiway he gunned the throttle, then shut down his engine and rolled silently to park perfectly in his spot. A bit of a show off, perhaps, but after all it was an air show.

I tried last night to do the gear-extend-in-a-climbing-roll thing and it is quite tricky to get it all coordinated at the right speed!

Joe

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PostPosted: Mon Jun 04, 2012 3:08 pm 
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Skulleader wrote:
Hello dear friends,

In first excuse for my poor English...

I found this conversation very interesting because the P-51 is one aiplane very aerodynamic and it's true that it's not easy to loose the speed before the approach.
During the approach phase with my P-51, my MP is 25" and my Prop Pitch 2700 RPM.

With this motor's setting my spark plugs do not suffering too ?

Please can you tell me if it's good to have my Prop Pitch at 2700 RPM for the approach or it's the good RPM ?
For my approach and with 2700 RPM, can you tell me the maximum MP that I can stay at 25" or up or below ?

And I always the approach must use the oil dilution ?

I would like to thank you for your help, best regards. Olivier

Bonjour Olivier,
You are correct. With a powersetting of above 20" (typically 25") at 2700 RPM you won't be suffering from plugs fouling. The 2700 RPM is recommended as it will give some additional drag when using low power. It is also the recommended RPM for finals and in case of a go-around.
However there is no reason to use oil dilution during approach. Oil Dilution is actually only a precautionary measure for cold weather operation. Whenever the next engine start is expected to be at low temperatures you will typically dilute the oil before engine shutdown on the previous flight. Oil dilution during normal operation is anyway of no use as at oil temperatures above ~50-60°C the induced fuel will evaporate without ever having a chance to dilute the oil.

Btw, don't worry about your english :lol: We perfectly understand you. Not all of the people around here are of english mother tongue anyway (me included).

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PostPosted: Mon Jun 04, 2012 3:42 pm 
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Quote:
And landing seems to be a bumpy affair, I seem to bounce even when coming down real smooth, nearly 0ft/min, at near 120kts, for a lightly loaded plane.


If you time your angle of attack to long to flat you will suffer from ground effect and bounce; overcontrolling in this phase might worsen things.
I dive a bit, pull up as to "airobrake", cut the gaz (if I now foul up my plugs I don't need to replace them in the air but it just doesn't happen), keep the bird close to the deck and let it gently stall.

It's always easier to tell then to do because it's all about timing.

Oh, and BTW, makes one wonder why the Mustang was designed without speedbrakes... :roll:

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PostPosted: Mon Jun 04, 2012 4:07 pm 
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Actually the A-36 Apache had dive brakes ;) But since P-51 is a fighter it didn't need any.

Straight in approach was a sure way to loose the aircraft, as after long missions and running on WEP setting often resulted in leting the gremlins loose, and those begun their symphony of destruction just prior the landing. It's a fighter, come in fast, turn sharp, and plant it down with confidence, either on both main wheels in slight nose-down attitude, or perfect 3 point (not 2 wheels and prop ;) )

Here's Approach and landing in the Crazy Horse TF-51:

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PostPosted: Tue Jun 05, 2012 9:57 am 
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Hello dear lonewulf47,

I would like to thank you for your explanations, now everything is OK for me...
This P-51 is very incredible, best regards.

Olivier.

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