Question concerning the Propeller lever during the approach step ...

[Skulleader]

Hello,

 

I spend many hours with my P-51D and I would like to know one thing during the approach step.

 

During this step please can you explain to me how you use your propeller lever, full forward or 2550 RPM ?

For the throttle lever no problem, just with the propeller lever...

 

In the page 30 we have all the engine ratings but nothing for the descent and approach.

 

Please anybody can help me ?

 

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

[Zabuzard]

I'm using the same as for the pre-approach which is mostly about 2600-2700 RPM. That's enough to handle the speed in the whole approach only with the throttle.

 

I don't know if the following site contains historical data but they list 2600 RPM at "Before Landing" too:

http://rwebs.net/avhistory/opsman/pursuit/section7.htm

[VanjaB]

Whatever works best for you. I keep it low @ 2500 RPM so there is less engine torque to deal with, and I usually try to land it mostly dead stick on final approach. I say 'mostly' because Im still getting the hang of it. Landing this plane cleanly has got to be one of the hardest things in DCS.

[VH-Rock]

Hi Skulleader,

 

I've seen multiple options used from real P-51 pilots in videos and asked them before too... Some like to use the full 3000rpm available for the aero-braking effect and some use 2500 RPM (Some probably use other settings too). I suppose, in all reality, as long as you get the aircraft back on the ground safely and manage the temperatures sufficiently, it doesn't make a huge amount of difference. Personally, I use 2500 RPM

[Flamin_Squirrel]

It's worth understanding the benefits high and low RPM settings will provide.

 

High RPM means you have maximum power available if needed, max aerobraking with a closed throttle and will, all else being equal, lead to higher engine temps.

 

Low RPM mean less power available (this isn't necessarily a bad thing as max power at low speed can be difficult to handle) and lower temperatures.

 

The landing checklist below the gun sight suggests 2,700rpm; a reasonable compramise IMO.

[Pman]

As with Rock the pilots I have spoken to have all given slightly different answers, Some use full 3000rpm and others as low as 2500rpm.

 

Personally I like the feeling 3000rpm gives me and gives me the most confidence of a solid and controlled landing.

 

Pman

[Skulleader]

Hello guys,

 

I would like to thank you for your explanations and the link, now everything is OK.

I go tested everything in flight, best regards. Skull

[MTFDarkEagle]

I'm setting the prop for 2700 RPM during the approach and leave it there. During the landing it won't be near that RPM (low power). Why I do this: if you have to go-around and you wank the throttle forward, you won't overrev the engine. If you were to have the prop lever fully forward, there is a possibility to overrev the engine. Plus 2700 RPM has a nice powerband :)

[Kid18120]

I really find myself more "succesfull at landing" with 2300 RPM setting, due to (way) lower engine torque when you put your wheels on the deck.

 

I sometime move the RPM setting all the way up to the max. to slow down if i notice i'ma a bit too high / fast on the approach but i always make sure to reset it to 2300 RPM on short final.

 

Also, a good tip, is to try a slightly "heavier" flare, so you touch down with all 3 wheels (3-points landing). I find this the most stable and easy to deal with after the touch down, mainly because at this point you can hold the stick backwards increasing the tailwheel load and maintaining stability.

 

 

 

S!

[Pman]

Its truly interesting to read about other pilots preference when it comes to something like this, Makes me want to try different ways of doing it just so I can say that I do it differently haha!

[sobek]

Pilots that think about noise will also tend to use lower RPM settings.

[Swoop73]

I was told the whole prop assembly "4 blades plus hub" comes to 450 lbs. accelerating that in a go around is bad enough and many are taught to just go to 40 inches to help avoid a torque roll. I was told 2700 RPM on final but as has been pointed out other real world Mustang pilots may use slightly different settings. One thing.. Setting RPM really low does not cut down on torque, it makes it worse as that huge prop is taking a bigger bite out of the air. Also, listen to Squirrel. Aerobraking from a flattened prop is a real thing and the courser the pitch the harder to keep it slow while coming down final.

[KLR Rico]

Aerobraking from a flattened prop is a real thing and the courser the pitch the harder to keep it slow while coming down final.

 

I think Swoop had a lot of good points, and many of those reasons are the same I use when I select maximum prop RPM for landing.

 

Just as an interesting tidbit, in regards to what I've quoted from Swoop's post... I've been told that a windmilling prop has as nearly as much drag as a solid disk with the same diameter. A fact I've always found rather mind-boggling.

[HotTom]

Pilots that think about noise will also tend to use lower RPM settings.

 

Pilots who think about noise don't fly Mustangs :cry:

[ZaltysZ]

Higher RPM = more responsive speed control: better acceleration with opened throttle and better deceleration with closed throttle. It is easier to abort approach or even landing this way if emergency (like sudden attack on airfield) arises, however it requires more precise throttle movement for keeping desired approach speed, because slight throttle movement might result in quick aircraft speed change. Also, running on higher RPM should help more in keeping spark plugs clean, which is pretty important when you are low and slow. I think manual recommends 2700 rpm, just because it is "maximum continuous".