X-Plane Up Elevator Authority

Flight Sims
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After you read this question you are going to think, “why doesn’t he just hook up a joystick and test?” With X-Plane it is very easy for me to screw up my VR controls and I would really rather not do that unless I need to. But we’re talking 10 minutes of work so, please, don’t feel the need to take time out of your day to test from me. I am only checking to see if this has been a noticeable issue for others. And the issue is this: In some planes, namely the STMA Husky, the Just Flight BAe Hawk 1A, the VSKYLABS DC-3 and the default 172, I run out of aft elevator at what should be normal landing speeds and sink rates with the power at idle. The in-game stick seems to be full aft. The control surface also seems full up. But the nose just stops tracking at about 1.2*Vso. If I carry power through the flare, I am able to flare. Otherwise I smack terra-firma a plane snapping nose low attitude. I have tried different CG positions. Aft helps a little. The problem varies is severity. It really isn’t such a big issue on the DC-3. But the Huskey can only be landed two points and at a fairly high speed. I’ve been running the “experimental flight model” which is required for most of the newer stuff I own. Oh, and the one plane that doesn’t exhibit this problem at all is the stock L-5.

Anywhooo. I don’t really care all that much. I fly helos 95% of the time but some of the bush strips @BeachAV8R has been posting would be much more challenging in something that can’t hover. Also, I remember a similar issue two years ago which was due (IIRC) to an inverse-ground effect. This is not that. Like I said, please don’t put yourself out with this one. I am just curious if it’s me and my unbreakable adherence to VR controls or if it is just how X-Plane works. Thanks.

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I haven’t had too much trouble with the default 172 G1000. Depending on weight / flap settings it can take near full power to maintain vref without a big sink rate, but otherwise it seems fine. I don’t know if that’s normal I just deal with it. :slight_smile:

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I have noticed it too Eric…rapid sink and not enough pitch authority for the flare. I just got used to carrying some power until touchdown.

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So here are my highly suspect, and highly unscientific observations. I flew a couple of the planes I know so that I could at least be in the ballpark. My method of testing was to take off, get configured for the landing and trim out the controls to neutral stick inputs while maintaining a fairly closely Vref speed.

I used the King Air 350 - Vref of around 120 (blue line), full flaps, trim neutral. Pulled the power to idle around 50’ and did not use any trim input, just a shallow pull to bleed off speed a few feet off the ground and the plane felt fine and stalled right at the bottom of the white arc (maybe 75-ish?) with no noticeable pitch forward that needed to be combated with more elevator.

Citation II - mid weight, full flaps and neutral elevator stick force, shot for about 102 Vref, same result…seemed fine in the flare, stopped flying right about where I expected, and did not require any extra pull beyond what I would deem normal.

Same for the stock 172. Came down the chute at around 65, full flaps, idle power, flare, stopped flying around 40 knots with no noticeable forward pitch down.

The A-1C seems to stop flying a bit too soon, and the flaps seem quite a bit more draggy than what I’d expect. With full flaps, idle power, and maintaining 60 MPH, my pitch is showing about -12 degrees down and 1100’ fpm…feels steep to me, but I don’t have any real Husky time…so maybe that is what it does.

Initiating a flare at that pitch angle with idle power requires some practice so you don’t smack it…and in my normal “X-Plane” flying, I preferred to come with 20 or 30 (instead of full 40) and keep some power in…particularly as I was regularly flying in that 10% over MTOW margin (hey…gotta make money for The Man).

By the way, when I opened my A-1C (STMA) it updated to 1.0.12 and I’m using X-Plane 11.50b15 with Vulkan ticked on.

I repeated the Husky test at 40 flaps and trying to maintain 70 mph down the chute - I run out of forward trim, pitch is -22 to maintain 70 and I’m showing 1800 fpm down. If you just let go of the stick at about 20’, the plane wants to pitch up (out of forward trim) and it will flare itself. Then it goes from 70 to 40 in a couple seconds and sets down firmly above the bottom of the white arc.

Ran the A-1C tests about 5 times and I run out of aft stick at about 48 or 50mph, which seems too high.

Tried one other thing, set speed for 70mph (again, the ridiculous -20 or so pitch), dialed in full up trim, which required nearly full forward stick to maintain the descent picture. In the flare, reduced pressure on the stick, and I felt like I could get a little more out of the flare. But…in essence, I feel like the Husky doesn’t have enough elevator authority in that last 10mph before it stops flying. I tried moving the CG aft 5 inches, but that didn’t really make much of a difference with regards to the speed at which speed decays at that Flap 40 setting.

All that to tell you… :man_shrugging:

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…and for giggles…I tried out the JustFlight PA28 Arrow…arguably one of the more accurately modeled aircraft. It is definitely done flying when you cross that 55 knot bottom of the white arc on the airspeed indicator…it positively falls out of the sky at that point.

So yeah…you’d need to fly some of these planes with some power in to make they act more reasonable in those last few feet.

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Damn you @smokinhole - now you have me going down the YouTube rabbit hole. Sigh.

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How do you manage to fly neutral trim descent at 65knts in the 172?? I can’t do that lol.

Edit: obviously the answer is you are a pilot but still.

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By neutral trim I mean…no stick forces. Trim sets a speed - so setting 65 knots with power on will also result in 65 knots when you close the throttle and the plane pitches down to “recapture” its desired trim speed.

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Thanks for the replies all. It sounds like it’s just a thing but one that has nothing to do with VR controls.

For those who don’t fly, just so you know, this isn’t a thing in GA aircraft that are loaded within proper CG. Normally you have robust elevator authority at idle right through stall (forward trim or aft, does not matter). The propwash that comes with power will add even more authority but the difference isn’t quite so pronounced as it is in X-plane. Stated another way: whatever nose movement you can achieve at low speed during the takeoff roll, you should pretty much be able to manage the same power over the nose on the landing roll at idle.

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One of the few planes I flew in real life that exhibited the same “I’m done flying” characteristics as you sometimes find in X-Plane was the T-tail Cherokee Lance. A burst of power wouldn’t save you in that thing. If you got slow too soon in that thing it would just mush into the ground spitefully while you held the yoke full aft and considered a career change. Of course…at the weights we were flying them…all the charts didn’t mean much. :rofl:

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That Cub is a rocket-ship!

He is a little tail-high on landing with full aft stick. But that is partly because the tundra tires change the geometry between the mains and the tailwheel. The angle with the ground is steeper. His two-point attitude would be tailwheel-first in a stock cub with 5x5.00s.

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Yep. I do remember that. Even the non T_tail version, the Cherokee Six, was nose-heavy. The T-tail Arrow IV was perfect. Those were all really nice airplanes.

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Did you ever get to fly DC-9s, MD80s, or 727s in your career? I always wondered if they had that characteristic too with those high T-tails.

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It’s absolutely possible to taxi the 172 on two wheels, by propwash alone. Or so I’ve heard… :innocent:

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@smokinhole have you tried enabling the experimental flight model and testing? I understand it was partly introduced in conjunction with thrandas Pilatus to help with some flight characteristics. Maybe it’ll change the behaviour you’re seeing?

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I flew the Beechjet briefly and the Embraer 145 for about a year. The -145 had the same detached floppy elevator system that the DC-9 had. And no, all those airplanes had very authoritative pitch control throughout their entire envelope. They have to. That’s part of the certification standard. I also taught in the Arrow IV, the Piper Tomahawk and the much maligned and forgotten (but excellent trainer) Beechcraft Skipper. All had excellent pitch control at low speeds.

And it is the ability at idle to move the nose, not change sink-rate, that I am curious about in X-Plane.

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I have taxiied my Pitts on two wheels. Takeoff from a stop with the tail up is quite easy to do and very impressive to see.

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Yep. As mentioned in the first post most things I fly now require it.

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This is because LR made a change to the flight model a while back, maybe with the early XP11 open beta builds, that changed how the aircraft behaved in ground effect. It “broke” a bunch of add-on aircraft, in particular those from Carenado/Alabeo. It took Carenado at least a year to begin fixing the FM, because rightfully, they have a lot of aircraft to fix, and wanted to wait until LR finalized the changes. There was holy hell raised about this in the .org Carenado support forum, but they didn’t budge. Any aircraft released after the FM changed, the Do228 for instance, didn’t have the issue. So, they knew how to fix it. The end result was that owners of earlier released aircraft began adding more horizontal stab authority with a couple of edits to the .acf. Unfortunately, I can’t find my edits with a quick search. I know that I did it for the B1900, Caravan, VSKYLABS EuroFOX, and ASDG Super Cub.

Ask any Arrow owner and they will tell you that this aircraft is much happier landing with a little bit of throttle on until the wheels touch. My second landing in an Arrow was at Danville, VA. I had two good friends with me, for whom I was trying to impress with my airmanship. Until then, I’d been flying mostly Cessnas. The flight up from Lawrenceville had been perfect. Right up to the point that I buried the main gear so hard in the tarmac that I had the line boy help me check the struts once we blocked in. I thought for sure I had collapsed one, he-he.

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Sorry missed that!