... a plane doesn't do "short field" landings with two big guys up front the same as when it's just me :/

Took a friend up tonight, who happens to be my CFI for instrument. He is bigger than I am. We flew around then did a few loops in the pattern. On the last circuit I wanted to do a short field takeoff and landing, as I have been practicing them quite a bit lately. Approached a little slower and steeper than my "normal" pattern. When we got over the threshold, I PULLED POWER OUT, and pulled back on the yoke, only to realize I had run out of elevator and we were sinking fast. I immediately put some power back (too little, too late) and then we slammed her down... much harder than I intended to.

Lessons learned.... I need to be more aware of my weight an balance, and plan accordingly. I should have realized how different the plane was balanced when we bounced three times on the "short field" takeoff.

I also learned that I can't practice all these things and expect the plane to be the same when when I'm loaded up. I probably need to do the same things with the plane loaded to gross and see how things are different? How did you guys learn?


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Night landing is best done at a field with no obstacles. This allows a soft field type shallow power/pitch approach. That way power can be used to safely feel for the ground.

Fuel and cargo can be added a little more each sortie to become familiar with gross weight or even overgross. With increased weight, energy management becomes more critical. Low ground effect will help us get a big load off safely. Staying in low ground effect as long as possible will help us zoom just over obstacles. Climbing just over obstacles saves zoom reserve in the form of airspeed to maneuver should the engine quit. Allowing the nose to go down in turns prevents stalling. Thermal and oregrapic lift, when managed, can allow climb with less pitch attitude to save zoom reserve.

Weight or density altitude or both will break any pilot of the yank and bank habit.

I learned the same lesson; was always taught to "fly the numbers", even heard Hoover make the same claim in a video. Nobody ever explained how the "numbers" change with weight changes to the aircraft. Ended up doing exactly what happened to you. Fortunately no harm done. It should be intuitive to most anyone to understand that as weight increases the amount of lift the wing can produce does not change and so will affect performance but as new pilots we place a lot of faith in the experts we consult during our initial learning experiences. I should also say that since I fly a Maule, it's POH/AFM does not contain all the fancy performance charts and graphs that you'll find in a Cessna or Piper manual. But what I learned was when slow and near the edge of the performance envelope, I imagine the aircraft riding on a bubble; this allows you to envision the results of getting too far behind the lift/drag/power curve. You will have to overcome the additional weight factor with more speed as the lift increases as a greater amount of air flows over the wing. Which also means your roll out will be longer, etc. A good clue to the landing condition would have been how much longer it took to get off with the additional weight.

Also understand that the stall speed changes with weight changes. (...bracing for impact...)

Some healthy and prudent stall recovery practice will give you a better feel for your aircraft's performance limitations. I encourage you to get up high and make some tests for yourself so you understand where the limits are for various weights. Take a kneeboard with some parameters listed such as as airspeed, flap setting, weight, and stall speed, sink rate (this one is important for the different conditions) etc, so you can make notes for each threshold. Its a lot of info so write it down so you can study it later when you're not busy handling the plane. My CFI didn't care for stall practice when I was a student. I've done a lot of it in my plane and discovered some issues with the plane we have since resolved that who knows how long it had been that way that previous owners lost confidence in the plane over. I have a lot more confidence in the plane now and KNOW it limits.

Don't pull your power, ride it. Set your AOA and flap setting and hold your airspeed. Remember, pitch is for airspeed. Some of the best short field landings require a quick blast of power just prior to touchdown. That's true spot/short field landing technique.

...and yes weight does make a difference

AKT

Good points by DeltaRomeo and AKT. If we get ground speed under control by very short final, coming into ground effect, we can increase pitch to slow even more and add power to both prevent bouncing and to increase kinetic energy lift with the prop blast. The steeper the power/pitch glide angle, the more demanding the timing of the application of greater pitch and greater power. Only with the apparent brisk walk rate of closure approach does this increase in pitch and power come naturally making the technique for shallow and for steep approach identical.

Airplaneflyer wrote:
Lessons learned.... I need to be more aware of my weight an balance, and plan accordingly. I should have realized how different the plane was balanced when we bounced three times on the "short field" takeoff.

How did the calculated weight and balance turn out. Were you within the normal operating envelope?

Looks like you have a '48 170? Does it have the original gear legs? They can provide a wild ride, especially when you're loaded up. Those legs were much softer and springier than the later models. They can really turn even the most innocuous bounce into another flight!

Pancaking it on is a different story. Sounds like you had a good revelation regarding decent rate close to the ground. Use of throttle in those situations is invaluable, but a little too much can screw you up too. Practice x 100

With just the front seats loaded, even with fat guys, it's pretty hard to get a stock Cessna 170 out of balance. I kinda doubt balance was the issue. But internet analysis of anecdotal evidence can be flawed.

With greater weight the wing must be pitched up more, than when lighter, to carry the load. Airspeed will be less, same as with high DA.

With the extra load forward, as in a loaded spray plane or this situation, the elevator will be heavier and after a full day the back will hurt.

With the load further back, as with these bush guys, the horizontal stabilizer and now down elevator create a rear wing to handle more weight and go faster (less angle of attack.)

Lots of good responses, much appreciated! I need to learn to control descent with power. I just threw some power in there and had no idea what was enough, too much or too little. On my other "short field" practice landings I was to pull out power and flare enough at the same time, and get the tail to hit first. This probably means I can be further behind the drag curve, but I'm not sure I'm totally comfortable with that just yet. I'll post a quick video of one of them for you guys to critique.
The weight and balance was just within the forward limits, and about 185lbs below gross.
I do have the original gear legs on my '48, and do enjoy bouncing around we pancaked that landing for sure. I wish I had that landing on video, but unfortunately I didn't take any cameras up.


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Just threw this video together quick. Landing is at the end of the video.

You DO NOT want to touch down tail wheel first. Very hard on the tailwheel and associated structure. A better method is to shoot for all 3 wheels touching at the same time when doing a 3 point landing (what some incorrectly refer to as a "full stall" landing) and the mains when doing a wheel landing. Before you get sucked into the whole STOL thing get proficient in normal landings which should include wheel, 3 point and crosswind landings. Once proficient then venture out into the world of STOL. Get proficient at landing with power off at various weights and being able to touch down at a selected point, this is going to pay huge dividends if your engine ever quits. When practicing landings select a point that is not right at the numbers, you want to give yourself a margin incase you come up short or encounter sinking air. In a nutshell, master the basics before moving onto other areas, it will make you a better pilot all around. Have fun and operate within YOUR limitations.

Kurt

Kurt makes valid points about the value of power off accuracy landings but power/pitch is better energy management for short field and high wind work. Your landings are fine. Don't beat yourself up. Learn everything you can. The first learned at the airport technique is not the best, it is just first learned for an imperfect test. My primary students learned to fly first and for the test later and still got done in far fewer hours than average. Flying is flying and what works works. There is more than one way to get it done safely.

Roger that. Practice time for me. Thanks for the advice you all.


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I try to get a feel for the plane on takeoff. How long it takes to get the tail up and how long to get airborne will tell you a lot about both CG and takeoff weight, both of which I have mental markers for on my home field. When you start flying at different density altitudes you will get another whole set of performance figures.

I fly a lot on my own, and with half tanks I LOVE the way it flys. I am sure 180hp would give me that in more situations.

daedaluscan wrote:I try to get a feel for the plane on takeoff. How long it takes to get the tail up and how long to get airborne will tell you a lot about both CG and takeoff weight, both of which I have mental markers for on my home field. When you start flying at different density altitudes you will get another whole set of performance figures.

I fly a lot on my own, and with half tanks I LOVE the way it flys. I am sure 180hp would give me that in more situations.

Yep... I think I'll have this strategy ingrained in my head now


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daedaluscan wrote:I fly a lot on my own, and with half tanks I LOVE the way it flys. I am sure 180hp would give me that in more situations.

I loved the way my 170 flew with me solo and half tanks too...hell quarter tanks were even better.

But it was a totally different beast with a big passenger, full fuel, and gear. The stock 170s are just like that, very weight sensitive.

My first "gosh it feels different" event as a student was my long dual cross country, in which we loaded wife and 2 kids in the back of a 172 (yeah, it was legal waaaaaaaay back then), which put the airplane right at calculated gross. The first landing, at Kenai, AK, was a little "hard" The second landing, at Homer, AK, was soft as a baby's bottom--and didn't stink, either. I'm a relatively quick learner, at times.

The lesson was never lost on me, that weight makes a huge difference. So later when I was instructing, I made a point of always teaching my students the difference, whether they were loading lightly in a 172 or heavily in a 182. Not only weight, but CG makes a huge difference, so that any time you plan on putting someone/something in the back, you have to account for that--it's often like flying an entirely different airplane.

Cary

The original pamphlets for landings (I, II, and III) were written decades ago. They're still a good read. Landing II explains adjusting your book landing speeds for actual weight. They might be helpful.

Landings I: http://faasafety.gov/gslac/ALC/libview_normal.aspx?id=56408

Landings II: http://faasafety.gov/gslac/ALC/libview_normal.aspx?id=56409

Landings III: http://faasafety.gov/gslac/ALC/libview_normal.aspx?id=56411