I agree with what Hotrod 180 just said about elevator not controlling sink rate without considerable speed. And the most common "run out of elevator" is after a balloon or bounce, both caused by arriving where we want to land going way too fast.

A huge advantage to the apparent brisk walk rate of closure approach is that there is no round out and close the throttle. If we have not allowed the apparent rate of closure to speed up, the throttle will not be closed until near or just after touchdown.

Short winged airplanes need a bit more speed for power off spot landing. That is why the speed recommended by the book is so high.

Zane,
I doubt that it is lacking in elevator travel or authority. It just sounds like a short wing. Too slow and they will start to drop and no matter how much you pull on the elevator, it’s not going to slow the descent. Spot landings are a cinch, get slow, get over the spot, pull what power is on off, and it’s all over. You can get slow, but it will take power at times, which you will figure out. If you want it act like a long wing, carry a few extra rpm in the pattern. One enjoyment I have in life is to take an instructor for my flight review that has never flown a short wing and watch them make divots when I make them land the first time.

Zzz wrote: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 power.

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

Good practice for the Bearhawk, with forward CG you have the same problem. Slow approach means lack of elevator. Sounds like Maule are the same if you are truly slow enough, according to the Backcountry STOL series on YouTube. He makes the same comment there.
A well timed blast of power does the trick. Otherwise VGs, gap seals, etc.

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.

Hey Zane,

The the only thing that matters as far as a short rollout is speed. if you touch down say at 50 with no throttle the rollout would be the same as touching down at 50 with 1/4 throttle and pulling throttle as soon as you touch down



Throttle doesnt matter for speed. it is just to slow your descent

So that being said the more throttle you have in. the lower your stall speed will be. because the high angle of attack of the propeller is lightening the amount of weight the wings must carry.

Hope this makes sense.

Aerodynamic questions because I don't always understand aerodynamics scientifically. In a high, powered pitch attitude, does a lift component of thrust or does prop blast on the interior wing sections create more lift? Would amount of thrust and/or straight jet propulsion change the percentage of each? Is there a specific angle where extra thrust doesn't affect airspeed significantly?

Robert Reser, "How to Fly Airplanes" explains this stuff with math. That is where I get lost.

Whichever, like many say, it works well for short field work.

TangoFox wrote:

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.

Hey Zane,

The the only thing that matters as far as a short rollout is speed. if you touch down say at 50 with no throttle the rollout would be the same as touching down at 50 with 1/4 throttle and pulling throttle as soon as you touch down



Throttle doesnt matter for speed. it is just to slow your descent

So that being said the more throttle you have in. the lower your stall speed will be. because the high angle of attack of the propeller is lightening the amount of weight the wings must carry.

Hope this makes sense.

It makes sense, been doing it for years. It just requires a little more power than I'm used to in Cubs to achieve the same thing, so it felt like I was doing something ill-advised. I suppose I wrote this post initially looking for someone to tell me there's something poorly rigged or unbalanced about this airplane and that some tweak could fix it instead of just using higher AOA and more power.

Thanks all for your input and tips.

Rob wrote: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

No short wing piper or maule experience but I agree 100%. Its very common to run the trim full forward for landing on the old 206 with the narrow horizontal when flown empty. Yeah, it’s hard to pull, and weird at first, but it works. Learned that from an old Aggie. [emoji1]

I was going to suggest we all (myself included re-read the OP) as it was indicating a shortage of trim, or elevator authority or both. I have no reason to doubt this, after all, our illustrious web wielder has been doing this flying bit plenty long enough to understand the concept of getting a wing slowed down, regardless of it's length or shape. Never the less Tango's post is solid, and yet it differs from what you describe in your initial post. As a general rule a ton of throttle is not out of the question, but how quick you shove it in there, and whether the situation warranted it will determine whether you are hanging on the prop, or squirting yourself across the LZ.... 'panic and brap' usually ends up in the latter...


But back to what really brought you here... If you think you are indeed short on trim or elevator it makes sense to investigate and rule the pertinent items before trying to modify your flying habits to suit an ill flying aero. In fact simply getting in a new airplane warrants a look at most of this stuff... My PA20/22 experience is far less than most of the 'guru's' here, but my understanding of the rag and tube Piper trim system is not lacking. The way I would direct it is from the most obvious to the least likely, and that list would go like this;

W&B / CG ) surely you've directed this already, but have you ruled out weight in the tail without seeing what it would do for your ground roll. We all know we gotta get the mass stopped, but I can't tell you how many airplanes I can actually get in shorter with a little weight in the back.

Rigging) Have you taken a smart level to it? If you put all the numbers on a piece of paper, find your HRL and zero your level to it, you can go through the entire plane in a matter of minutes. Correcting things on the other hand may take a bit. A fairly recent rebuild is no indicator of todays rigging BTW, these rag and tube things move and tweak as much as a living tree....

The stab yoke) they fly just fine with the yoke upside down, they just run out of trim too soon as the taller side of the diamond runs into the jackscrew tower. Incidentally, yours should be upside down when compared to a PA18, which would make it an easy mistake for a rebuilder who dabbles in both.

The rear stab inner tube) Piper did not put a zerk in the rear stab inner tube (I do on every rebuild, and there is even a hole where you would weld a high heat nut to accept it) as such it is incredibly common for the rear tube to be anywhere from sticky to fused solid from rust and dirt. Your stab will still move some, but you will not have full range trim.

And last, but still fairly common) rear section of longerons starting to 'sag' uphill. The more nose heavy, or the more power you have to use on landing, the more common this is going to be. The sequence goes like this; you fly a nose high approach that leaves you landing tailwheel first. Mostly gently, and not very often, so no big deal sooner or later your tailwheel finds a boulder or you 'arrive' a little more abrupt, and those spindly 5/8" tubes begin to start drifting upwards. Whats really happening is the tail is twisting about the axis of the stab. The worse this gets the less flair you will have, meaning more power on the landings and more tailwheel first landings. This would be one of the first things I would check on the longer bodied Pipers, as every one I have been in to has been bent uphill at least some.

Anyways... investigating all of this is not a couple hours work and at a minimum puts your mind at ease as well as giving you a sense of direction to focus your energy.

Take care, Rob

Rob wrote:….Rigging) Have you taken a smart level to it? If you put all the numbers on a piece of paper, find your HRL and zero your level to it, you can go through the entire plane in a matter of minutes. Correcting things on the other hand may take a bit....

Interesting to find this very matter-of-fact mention of the Horizontal Reference Line.
A buddy of mine was having a tough time leveling his Pacer for weighing-in purposes.
It had been rebuilt and the stock "screw hole" and "center-punch mark" were no longer there.
He tried plumbing down from the datum (Wing Leading Edge) and measuring to the MLG--
one wheel was farther ahead than the other, so which to use? (he's a very precise guy).
Plumb the firewall, plumb the tailpost- they didn't jibe with each other.
After much research, he finally discovered the HRL which was shown on his big fuselage drawings.


I do have to chuckle about your reference to zeroing your level to it though.
Yes, that's the quick way to do it, and it works great if done properly--
but it reminds me of a comment I read once about the invention of the smart level being responsible for more mis-rigged airplanes than anything else these days.

There was a discussion on the SC site not too long ago about setting wing washout with a smart level,
as I recall there was lots of misinformation and/or half-truths mixed in there with the good stuff.
Made for some good arguments, err I mean discussions though!

Hi Hotrod,

You'll get no argument from me there.... it's nothing unique to this scenario that an exceptional tool in the hands of mediocrity will most often yield poor results. Just look at the amount of brand new Carbon Cubs that are on their second or third prop strike inspections or ground loops repairs .
On the other hand, the frequency of those incidents does not negate the superiority of the tool in question in the hands of a well educated / experienced end user.

When I am looking at a cub for the purpose of rigging, I zero the level on the upper longeron, the door sill, the window sill, the tube between the gear legs, and the firewall (+90degrees). In the case of a cub, these should all agree. They will not though, I then remove any wild cards, as those will be areas to address/repair. The balance will have a variance of a tenth of a degree at most, and can then be averaged for our purposes. It is also very handy to have a laser with a selection of lenses. My smart level has one on it. With this you can check the top deck for squareness, or shoot a line on the lower longerons for uphill bending, something otherwise difficult to check as they curve in, making the use of a string less than precise.
Anyways, I have no qualms about the use of spirit levels, plumb bobs, and string lines ( I once made a life out of being a carpenter). I just have no illusions regarding the superiority in accuracy of modern tools.
Take care, Rob

As a side note, I have been asked to look over Cubs on more than one occasion where the numbers just don't agree well at all. In fact this is very common. IMHO, Cubs like this are ready for a jig, and are worth no more than 'core' value, regardless of engine condition or other bling. Same with a cub that has a poor AOI. These issues are an order of magnitude more complicated to deal with than even an engine r&r.

Take care, Rob

Rob wrote:..... it's nothing unique to this scenario that an exceptional tool in the hands of mediocrity will most often yield poor results. Just look at the amount of brand new Carbon Cubs that are on their second or third prop strike inspections or ground loops repairs .
On the other hand, the frequency of those incidents does not negate the superiority of the tool in question in the hands of a well educated / experienced end user.....

Well put.
KInd of like a newbie in a tricked-out supercub,
or behind a "race gun" pistol.

Where were you when I was spraying, Rob? I flew Pawnees I could see the bend in the lower longerons and could only ground loop around in one direction because the tailwheel was at an angle.

contactflying wrote:Where were you when I was spraying, Rob? I flew Pawnees I could see the bend in the lower longerons and could only ground loop around in one direction because the tailwheel was at an angle.

While I appreciate the sentiment contact, the only difference between the way you were looking at airplanes back then and the way I do today is the cool tools that are available now. Either a guy knows what to do with them or not...
Had I been around when you were flying Pawnees, I would have come by with a plumb bob, a chalk line, and a 30" whiskey level.... Maybe a big hammer, duct tape and some bailing twine

hotrod180 wrote: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.

This made me laugh thinking about the 2nd time I flew this particular aircraft...

I had a friend along, we departed Beagle Sky Ranch, and I dialed in a little extra forward trim to lighten the tail, as others have mentioned, thinking it's help. Well, it did a little, and I got the aircraft off the ground, established a climb and reached up to trim to hold that climb hands-off.

One of the damned cables jumped the pulley track and caused the trim crank pulley to bind. Glad I had my friend with me, because he fiddled with it and fixed it (though it did take a few minutes) and then I was able to trim. The whole time I was holding a fair amount of back pressure to keep a shallow climb-- not fun. The indicator stopped working for the rest of the flight; not a big deal, but kinda mysterious. That trim cable has a pretty good wowowowow in one section that probably necessitates a replacement.

Long story short: I'm now a little tentative with cranking too fast on the trim crank.

Z,
Flew a nice little modded Pacer all last summer, long wings Stol, gap seals. original tail, 29" tires
Trimmed full one way to land, Also used a bunch of power real quick and short just prior to the tail touching the ground!

When I picked it up in CO. to take it to AK, (about 10 years ago)it was a miserable little bitch to fly!! Stopped at home and completely rerigged it before leaving for AK, me and the Jake dog had a good time all the way there!

Move to the Wilga, if you don't have a full blast of Power to arrest the fall and to pull the nose up, you have to land at 70 kts to have enough authority to raise the nose or round out!!

Short landing with my old M6 was always with about 1200 rpm with a little blast to lift the nose and set the tail wheel on the ground.I trimmed it nose down all the way to add flaps to the elevator.

YMMV!!

Went out today for about an hour and shot a few landings. But, I wasn't very scientific about it because I busted the first rule of diagnostics: I changed two variables at once.

I loaded about 40 lbs of stuff in the baggage as far aft as possible, then overtrimmed up for the approach. This was showing about 82 mph indicated on the ASI, which is about 63 mph when corrected for being f'd up.

I had to hold a fair amount of forward pressure, and cycled between about 1200 and 1500 rpm to hold what I felt was an acceptable sink rate.

Holy smokes, what a difference. I had a ton of elevator authority and didn't even have to power up much to arrest the sink, which means I probably could have gotten a little slower.

Knocked out a tail-low wheelie and 2 three pointers with relative ease compared to my previous technique of yard the elevator back and blip throttle to make it work.

Wind was 8-10 gusting 14 or something, so part of that could be the perception that things were slower and working better, but you can't spoof control authority. It just felt better.

My suspicion is that the balance made all the difference more so than the trim. Here's my trim position after landing:

You have quit a bit of trim left so I would agree the weight helped a lot. I would use trim before adding extra weight but a good survival kit and tool bag will hit 20lbs or more so you really would not be caring useless/extra weight. If I am running light I try to get my survival gear to the back of the pod or extended baggage. As you slow down more you will like the power on approach.
DENNY

I understand adding ballast but only if it’s something you need to carry in the airplane regardless... for me it’s tools.

In my Pacer it was 4 full turns nose up from cruise. IMO, in the Pacer you have to get comfortable with forward pressure on the yoke on approach. What you’ll find is the sweet spot where as soon as power comes out (I carried typically 1500rpm) your trim is neutral and you still have elevator authority. FWIW, I probably flew approaches as slow as anyone in the Pacer, 55-58mph. I was comfortable with the higher AOA and forward pressure but by no means was hanging on the prop.

Find that sweet spot on a slow approach with trim where when you get to pull power or even add a little shot to settle it the plane is trimmed for no pressure on the yoke.

PS, don’t forget to crank it back 4 turns the other way for TO, don’t ask me how I know!

Zane, you were looking for a Pacer a while back, I'm curious (aka nosey) as to whether you bought this one, bought into it, or ?
Also, I wonder if there's anything you can do to correct that airspeed indicator--
replacement, overhaul, or maybe tweak the pitot tube?

And ditto what TxAgfisher said about using gear (tools etc) as ballast.
And about resetting the trim.
I like to reset my trim to the takeoff position right after I land--
usually while I'm taxiing in, but sometimes not til I park.

A while back I forgot to do either.....
also didn't check the A in CIGARS ("attitude") as closely as I should have before takeoff.
Right after breaking ground it went into a helluva climb...
luckily I wasn't in a tight spot, so I could dial the power back a bit and crank the trim back forward again without a mishap.