When max RPM on landing

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Eugene Kremlev
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When max RPM on landing

Post by Eugene Kremlev »

Hey, guys. In the tutorial write "During final stages of approach..." - this is when? My landing - 20 or 23 mp & 2300 rpm, immediately after touch - max rpm, flaps up and cowl flaps up. Always - soft landing and applause.

But, if use max rpm before touchdown (500ft and below), the landing configuration is broken and the plane starts to lose speed and sag, need to turn the trimmer and lift nose, up 25 MP and above (total imbalance before landing). Almost always - no applause.

CAPFlyer, guys - help me understand and correctly apply :)
Last edited by Eugene Kremlev on 17 Feb 2018, 02:20, edited 1 time in total.

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CAPFlyer
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Re: When max RPM on landing

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Typically, I advance to full RPM as I join the glidepath (visual or instrument). I should be under max governed RPM by then with whatever power is required to hold my approach speed (usually around 20"-23"). If I'm still carrying enough speed and power that the props are at 2300 RPM on their own, then I'm either too fast or I'm dragging it in with power, two things I shouldn't be doing.

If you wait until at or after touchdown, then you don't have the power available should you need to go around. You don't want to be trying to bring up the power and props at the same time while trying to climb because it puts a lot of unnecessary stress on the engines for one, and it can upset the airplane if the props don't hit the governor identically (which can happen even in the sim).
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Eugene Kremlev
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Re: When max RPM on landing

Post by Eugene Kremlev »

CAPFlyer wrote:Typically, I advance to full RPM as I join the glidepath (visual or instrument). I should be under max governed RPM by then with whatever power is required to hold my approach speed (usually around 20"-23"). If I'm still carrying enough speed and power that the props are at 2300 RPM on their own, then I'm either too fast or I'm dragging it in with power, two things I shouldn't be doing.

If you wait until at or after touchdown, then you don't have the power available should you need to go around. You don't want to be trying to bring up the power and props at the same time while trying to climb because it puts a lot of unnecessary stress on the engines for one, and it can upset the airplane if the props don't hit the governor identically (which can happen even in the sim).
That is: approach — 23"/2300 rpm, glidepath — 20"-23" and max rpm (when light on four orange lamps). Correctly?

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CAPFlyer
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Re: When max RPM on landing

Post by CAPFlyer »

Yep.
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Eugene Kremlev
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Re: When max RPM on landing

Post by Eugene Kremlev »

CAPFlyer wrote:Yep.
I have the necessary speed only at around 27" (if RPM max) on approach. Current TW — 69000 lbs.

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Re: When max RPM on landing

Post by CAPFlyer »

It's been a bit since I last flew it, but something doesn't seem right there. With less than full flaps and on approach, you shouldn't need to carry that much power.
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Eugene Kremlev
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Re: When max RPM on landing

Post by Eugene Kremlev »

I have on approach - “approach flaps”. Full flaps I have on 500ft and below. All system on approach and landing correct, according to tutorial. What could be wrong? I don’t understand. Please, tell me.

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Re: When max RPM on landing

Post by CAPFlyer »

I don't know. That's why I need to fly an approach and see what I get.

How much fuel did you have onboard when you took the screenshot?
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Eugene Kremlev
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Re: When max RPM on landing

Post by Eugene Kremlev »

CAPFlyer wrote:I don't know. That's why I need to fly an approach and see what I get.

How much fuel did you have onboard when you took the screenshot?
About 300 - 320 gal. in each tank. Oops, max allowed 900 gal. for landing. I forget :) Now I'll try with 800-900 gal. fuel.

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Eugene Kremlev
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Re: When max RPM on landing

Post by Eugene Kremlev »

So, before takeoff: tw - 64700, fuel 415 gal., center of gravity - 25.0%, gw - 72%, payload - preset "heavy". Headwind, left 7-9 knots. Free air temp. - 30-32C.
Approach: speed 90-95 mph at 25"/max PRM (need min 110-115 mph), flaps "approach". At 23"/max RPM speed around 90 and below without full flaps.
At 23"/2400rpm (as recommended in the branch, where the checklist) full order and keeping all the necessary speeds.
What to do :) ?

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CAPFlyer
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Re: When max RPM on landing

Post by CAPFlyer »

I had to go back and find one of my old posts on the Connie and landing procedure. I found this from me and one from "BendyFlyer" that should help -
CAPFlyer wrote:The normal "airmanship" of the time dictacted that you maintained cruise RPM during the descent until you entered the terminal area (generally within 20 miles of the destination) or started the approach (depending on airline) at which time props were increased to Climb RPM (2300 on the L-049) and the power maintained at square. I've found this procedure to be perfect for the L-049 in the sim with me usually adding a little power (25") once established on the approach prior to beginning the descent on the glidepath and then easing it off as I deploy the gear, approach flaps, and begin descent on the glidepath. Landing Flaps are added around 500' if weather is good, and 200' if in hard IMC with no power change.

One thing to note - landing flaps usually aren't deployed until landing is nearly assured because they add a lot of drag to the airframe when executing a go-around. By leaving in Approach flaps, you can also retract quickly to takeoff flaps as you add power to go around without nearly as much of a loss in altitude and lift.
BendyFlyer wrote:Couple of things. In real world operations - Prop RPM will be left at the cruise settings on descent but MP would be reduced steadily, in other words, on descent as the speed builds up you bring the power back at no more than 1" MP per thousand feet to avoid shock cooling piston engines. Remember there is a supercharger or blower shift passing approximately 12,000 ft which will increase the MP anyway.

On a large heavy aeroplane and the Connie was such an aeroplane you needed to and still do have to have what is called a level segment, once or twice where you would go level say for 30 secs or a minute to let the speed bleed back to approach and final speeds. Prop RPM was not brought back to maximum until 1500 ft or 500 ft depending on whether you are joining for a circling approach or straight in (such as an ILS). There is another thing to remember for speeds generally and on descent, you may have to limit the speed due to turbulence as the manuouevring speed is a big limitation on all aircraft and the Connie was no different. The last thing you want on an aeroplane like this is to get stuck going fast once you get to within about 10 miles, your aiming for a stable, moderate speed to then meet flap and gear extension speed limits.

Descent speeds varied from operator to operator. However, descent profiles under instrument conditions were for a approach designed 500 fpm descent. Most flew profile descents which is a 3 degree profile all the way the same as the ILS, the rate of descent will vary according to the speed, if you look at an ILS approach plate speed table you will see the rate of descent required v speed. With a profile descent you can stay higher and still fly the instrument approach and not bust altitudes at critical check points.

The name of the game was to not over boost the engines or have too high power on descent to avoid shock cooling, endless mixture changes and prop changes but to get to about 50% power on final at the correct speed. It takes a lot of practice to get it flowing smoothly. Just remember this is a big and heavy aircraft even by todays standards'.

Hope this helps!
So, the power is a bit higher than I remembered (25") with 2300 RPM, and BendyFlyer was correct about moving the props forward around the time you put the last stage of flaps out, so I apologize for the error there. I'm about to do a short flight so I can get fully into cruise and then do the full setup, so we'll see what power settings I see, but remember, it's not a problem to carry power on approach in these big airplanes. You just don't want to carry too much of it.
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Re: When max RPM on landing

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I flew a flight this afternoon from Phoenix to LA with 17 pax and "light" load of fuel to start as a test case. I confirmed again that trying to fly a modern STAR with the Connie typically isn't a good idea, but that's beside the point. Flying in, once I got down and was able to start setting up, I had my throttles set at 25"/2300 RPM once I leveled off just before joining the glideslope, was able to reduce on the glideslope a bit and then as I fed in the last flaps and brought the props to full, I didn't notice any real bad tendencies. The plane slowed like I expected it and I crossed the fence at a reasonable speed (90 knots I think) and touched down without problem. I am going to do a second flight tomorrow to verify that I wasn't missing anything.
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Eugene Kremlev
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Re: When max RPM on landing

Post by Eugene Kremlev »

Great thanks, CAPFlyer! Write about your flight. I'll wait.

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