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Pacer elevator authority in the flare

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Pacer elevator authority in the flare

Been flying a PA-22/20 for the last couple months; a nice bird that was rebuilt in the late 90s by the Pacer gurus at Steve's Aircraft in Oregon. It is equipped with MicroAero VGs on the wing and under the horz stabilizer.

The majority of my flying hours are in Cessna 170s, Super Cubs and their variants, Rans S7, etc. Transitioning to the Pacer has been a little bit of an interesting experience, mainly due to the higher wing loading.

It didn't take long to realize that the airspeed indicator reads about 20 mph fast in the 60-90mph region (using the GPS in calm air), so it's been weird to fly approaches at 85mph indicated. That's fine, I can feel what I think is about the right speed and attitude with my butt anyway.

The issue has been that I run out of elevator in the flare, and usually panic and brap the throttle a little. During a short landing this can kind of sabotage a slower rollout speed.

Anyone else who's well-versed in the Pacer know if this is par for the course when trying to land short? I've never run out of elevator in a Cessna or Cub. But I end up with this thing at the stops and unable to ease my descent without (more) power.

Would a little aft ballast increase elevator authority? Gap seals?

The W&B on this aircraft empty is about 1094 lbs and the CG is right smack in the middle of the range when loaded with 2 guys.
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Re: Pacer elevator authority in the flare

Zane,
I experienced the same thing when I put VG’s on mine and a friends Pacer.
Checked control travel, cable tensions, and even tried a gap seal on the horizontal stab to elevator. None of that helped.
50 lbs of play sand in the baggage compartment fixed everything.
One original light weight 135 and one Tri-Pacer converted that was loaded up.
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Re: Pacer elevator authority in the flare

d.grimm wrote:Zane,
50 lbs of play sand in the baggage compartment fixed everything.


I was worried someone might say that. I was hoping to not fix the issue with added weight #-o

Thanks Dave.
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Re: Pacer elevator authority in the flare

I not sure what the issue is.
1. Arresting descent:
With the short wing of a pacer you will either need power or speed to stop the decent. When slow, with no power the flair just won't do it. When slow try coming in with about 1600 RPM keep in on through the flare. Once you have arrested descent just roll in on the mains (how hard can that be :oops: ).

2. Not enough elevator authority.
Where is your trim set?? I was just flying with a new pilot in his cub yesterday, he was told to put a case of oil in the extended baggage to help him three point. He was landing with his trim pretty far forward. Once he started trimming the plane for hands off landing speed his problems went away. If approach speed is say 55 and touchdown speed is 45 it means you will have forward pressure on the yoke/stick as you come in. That is not something most pilots are used to. Remember a pacer has a adjustable horizontal stabilizer not just a trim tab. If not trimmed properly is will have a much greater effect on the plane than a fixed horizontal stabilizer would. I am sure you know this, but just a point for pilots not used to a adjustable horizontal stabilizer. Weight in the back will have the same effect, but it is extra weight, see if you can do the job with proper trim setting first.




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Re: Pacer elevator authority in the flare

Power/pitch works really well, Zane. The short wing Pipers will really sink, but not stall, at slow speed. When at powered slow flight pitch, the extra power to prevent too fast sink rate doesn't increase speed too much.

The prop blast keeps the elevator working well. When slow enough, power can be carried to the ground.
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Re: Pacer elevator authority in the flare

As mentioned, aft ballast (chocks, tool kit, baggage as far aft as you can get them) and full nose-up trim should help.

As far as mods go, I believe PA18 tailfeathers are bigger than 20 or 22.
I think Svenns Aviation has an STC for them.
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Re: Pacer elevator authority in the flare

Well, I'm new to the Pacer, but not exactly a noob :D I'm fairly confident with managing pitch and power, sink rate, and adequate airspeed for control surface authority but this one has revealed my weakness I suppose.

Denny, what you describe is very close to what I've been doing, carrying about 1500 rpm on short final to allow for a little greater pitch attitude and slower airspeed.

As for trim, I have always been a fan of trimming just outside the hands off point to avoid hysteresis. It's usually forward for wheeelies and aft for threepies. As to exact trim position, I don't know. I'll check the travel indicator after landing next time.

Never been much of a fan of the technique some use in the Husky for 3-points where very aft trim is used and you relax forward pressure in the flare. Feels uncomfortable and maybe like a recipe for accident if you fumble something.

In an early attempt in the Pacer though, before I confirmed the ASI was reading high, I really got overtrimmed and behind the curve on an approach. I was doing about 68-70mph, which would have actually been 50mph, though I don't think the ASI error is constant across the range. Anyway, I ended up having to push really really hard on that one to keep the wing alive.

I tried trimming up in anticipation more recently, thinking perhaps it would buy me some more authority once I slowed in the flare, but I snoozed and didn't managed airspeed well on short final because it required constant forward pressure. I was preoccupied with the surface or something.

Another converted Pacer I have flown didn't feel the same way in the flare. I think I flew that one at 80mph on final, gradually slowing it to 70 over the threshold, and it felt more authoritative. But I also wasn't trying to work it short by feel.

I'll head out and try some more approaches and try to be a little more scientific about it before I add the aft ballast.

I am aware of the PA-18 elevator STC, Hotrod. I wonder if there are any operational considerations for that, or if it just works better when slow.

Other than this issue, it's a very pleasant-flying airplane, which makes me think it's probably just my technique.
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Re: Pacer elevator authority in the flare

This is all really good information for me. I have always been a Cessna guy, with Champs and Tcarts thrown in for good measure. When I started flying this stock 125hp Pacer I was really disappointed with elevator authority. I was hoping that the vortex generators would cure those issues, but am wondering now after reading this.
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Re: Pacer elevator authority in the flare

Trim all the way nose up to the stop. You get used to the relatively light forward wheel forces needed to make the approach while keeping the nose where it needs to against the full trim. A blast of throttle up to 1500-1800 rm at 30' (earlier than one might think) brings the nose up for a three pointer. People scoff at flying an untrimmed approach, but who cares- it makes a significant difference.

I never got the hang of three points when solo without full tanks or a bit more power than usual.

I knew someone who modified the elevator stop a bit to give a couple more degrees with an improvement in landing until he went out for some stall practice, and promptly had a mechanic fix his modification somehow- it startled him that much. Apparently there is a reason the elevator limits are where they are.

Short wing Pipers are way fun to fly though.
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Re: Pacer elevator authority in the flare

One of the things i like about the pacer is how easy it is to put in a bunch of trim quickly. Maybe try trimming for your target airspeed, then on very short final reach up and twirl in a bunch of nose up trim. If you have to go around, just reach up and wind it back to a more appropriate setting.
Last edited by hotrod180 on Sun Jul 01, 2018 8:40 am, edited 1 time in total.
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Re: Pacer elevator authority in the flare

Trim indicators can off just like you airspeed. When you land stop and see how many turns you have until full up. I would try a few landings with it full nose up and see how it feels. You can adjust back from that point if needed. While we are on the topic of the trim indicators, everyone should know how many total turns of travel you trim has and how many turns from front or back you set your trim for takeoff and landing. That little wire always seems to break in the middle of a long trip or first day of hunting season.
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Last edited by DENNY on Sun Jul 01, 2018 11:08 am, edited 2 times in total.
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Re: Pacer elevator authority in the flare

Zzz wrote:...As for trim, I have always been a fan of trimming just outside the hands off point to avoid hysteresis. It's usually forward for wheeelies and aft for threepies. As to exact trim position, I don't know. I'll check the travel indicator after landing next time.
Never been much of a fan of the technique some use in the Husky for 3-points where very aft trim is used and you relax forward pressure in the flare. Feels uncomfortable and maybe like a recipe for accident if you fumble something.....


First of all, I didn't know what hysteresis means, so I googled it up.
All that did was confuse me-- worse than dynamic proactive, reserve of zoom, etc!

Anyway, I generally agree with you on the trimming extremely nose up and pushing against it.
A friend of mine bought a Pacer years ago & the guy who checked him out in it taught him to do this.
To me, it always seemed like it'd be too easy to get dangerously slow if you got distracted during the approach.
Better (in a Pacer anyway) to wind in the full nose up trim just before or as you're flaring.


His checkout pilot also taught him where to set the trim for takeoff.
The first time I flew his airplane, with him in the RH seat, I noticed there wasn't a takeoff or neutral position marked on the trim indicator.
He wound the trim all the way to the stops, then wound it back X number of turns. "There you go" he said.
Everything was fine until we broke ground, the nose went up to a scary attitude.
The kind of nose-up that could easily lead to a departure stall.
I pushed the nose down, then when I went to wind the trim back down I turned the crank the wrong way and made it even worse!
Got it sorted out on the second try. Then I asked him why he set the trim like that.
"I don't know, that's just how George taught me to do it".
(he wasn't the sharpest knife in the drawer BTW, and neither was his checkout pilot)

Rather than "neutral", I trim my 180 somewhat nose down for takeoff--
that way the tail come up by itself without me having to push it up.
Seems to make for an easier better takeoff.
Then I trim the nose back up for the climbout.
But I don't see any advantage to setting the trim so nose-up for take-off..
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Re: Pacer elevator authority in the flare

Hysteresis = dead zone, laggy region of control.

I read once where a fighter pilot would trim so that he had to hold control pressure one way or the other so that any control movement would result in pitch change instantly.
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Re: Pacer elevator authority in the flare

His checkout pilot also taught him where to set the trim for takeoff.

My instructor also taught me to use take off trim for landing. My Pacer was all original...cept the VG’s. Dual and solo I discovered 60 pounds against the rear bulkhead gave me enough elevator authority. 55 mph over the fence...just under 47 or so at flare.. what was disturbing was holding the yoke all the way back...the urge to drop the nose and push the throttle was almost overwhelming...felt like it would stall and drop, might break something....only dropped it one time in Talkeetna...might have flared 3 feet to high...it was my first night landing....no moon, clouds, darker than a dark room...only the runway lights. Before my gear failed...(due to a bad welding welding repair)...single puck groves, 8:00/6’s and a Scott 3200 tail wheel. After 150 or so landings I got to the point that the tail wheel would kiss just before the mains.. always aimed for the threshold as my touch down point...and always missed it by plus 20’ to 50’.. with hard braking would have her stopped before the second runway light or 400 feet beyond the threshold. She weighed 1023 empty, solo, full fuel and altitude densities 2,000 to 4,000 feet below sea level, take offs were pretty short.

Now if I ever get the rebuild done...3” extended supercub gear, 26” Goodyear’s, wing mods and Pa 18 tail surfaces...with VG’s...will have to relearn...will probably have a completely different feel to it...just wish the wind blew less around here...still not comfortable with crosswinds..
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Re: Pacer elevator authority in the flare

I'm reasonably sure I will draw fire for this, but since both the mechanical design of your trim system, and physics agree with me, I will suggest it.
When I fly a cub (same trim system) that runs out of elevator sooner than I care for, I get it as slow and stable as I care to, and then start rolling in nose down trim. How much depends on the particular aircraft and w&b, but full nose down is certainly not out of the question.
Study your stab to elevator relationship and you will find that this gives you the greatest deflection.
As for control pressures, remeber, you were already at the point of not having much, so you're really not going to be carrying much. This is for a power on approach, and adds 2-3 degrees, so it's only going to help the last ragged edge, and only a minimal, but tangible amount.
This is the no $ cure, if you want to throw a few bucks at it, cub tail feathers and/or gap seals, are your best friends.
Take care, Rob
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Re: Pacer elevator authority in the flare

And this is assuming you have verified the yokes is on the jackscrew right side up
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Re: Pacer elevator authority in the flare

"Never been much of a fan of the technique some use in the Husky for 3-points where very aft trim is used and you relax forward pressure in the flare. Feels uncomfortable and maybe like a recipe for accident if you fumble something."


Zane, first I have heard of this technique. In the Husky, I trim full nose up on 3 point landings and still have to pull in the flare.

In the Pacer, try some landings with one less notch of flaps, you may be surprised it will still fly slow, also just a tad of power throughout the flare will help airflow over the elevator. Its not that its producing flow, its keeping the prop from blocking airflow.

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Re: Pacer elevator authority in the flare

Assume you’ve checked your elevator deflection against book numbers. It is not uncommon for a jack screw yoke to be installed upside so you don’t get full travel. Otherwise, the short wing is flown differently than the Cessna series and its longer Piper brethren. Even with VGs. Your shortest, slowest landings will be with power. The heavier you are, the earlier in the flare it’s brought in and the more RPMs you use. You feel the seat start to drop under your derrière, add power. A power off approach will be faster in order to maintain elevator authority. You don’t get a lot of help from ground effect with the little wing. You can feel a C170/180 come into ground effect. A short-wing will plow right right on through any ground effect unless you get some air flow.
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Re: Pacer elevator authority in the flare

Zzz wrote:….The issue has been that I run out of elevator in the flare, and usually panic and brap the throttle a little. During a short landing this can kind of sabotage a slower rollout speed..... I've never run out of elevator in a Cessna or Cub. But I end up with this thing at the stops and unable to ease my descent without power. ....


I got to thinking about this comment from your original post.
"Run out of elevator"....are you saying that the yoke is full aft and you still cannot obtain a three point attitude?
Or are you saying that full aft yoke at the flare doesn't arrest the sink rate?

That second scenario is very likely with a steep / nose high / slow airspeed approach.
When behind the curve like this, lots of airplanes will rotate to a higher AOA when full aft elevator is applied,
but without reducing the sink rate at all-- resulting in an arrival ranging from somewhat firm to KABLAM!
There's just not enough airspeed there to provide the energy required to stop the sink.
In this case, adding some power will cushion the arrival.
Timed correctly, it doesn't even have to be that much power, esp if ground effect helps out at the same time.
The smaller wing area of a pacer may not benefit from ground effect asmuch as a Cessna, but it is there and will do something.
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Re: Pacer elevator authority in the flare

ROB
When you talking about running out of elevator authority, are you talking about in the landing flair? When you say you are rolling in nose down trip are you moving the front of the stabilizer up or down?
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