New here and new to Super Decathlon flying

[dedaaru]

Hi folks, got my private ticket last year and just got two lessons in a super dec. I am s**t scared of wheel landings for now but love the way the plane flies, slips and does all kinds of things. Love having the flight stick in my right hand and still need to teach my left hand the difference between the power and trim levers Just found this forum and would love to learn from you all!

 

[Bob Turner]

Try a Cub for learning tail wheel.

 

[BB57]

I learned to fly in a Supercub and first flew a Citabria after I had my PPL. The Supercub is a bit more demanding than a Citabria, but not significantly so.

I found the Citabria on spring gear very easy to wheel land, while the early oleo strut CItabrias were a bit harder (for me) to wheel land do to that initial "mush" when the mains touch interfering with the timing to release some back pressure to hold it on the ground.

The Deathlon's shorter wing and semi-symmetrical airfoil means it stalls a couple knots faster, but the extra couple knots is a non issue for a wheel landing, as long as you are not already adding extra final approach speed for a wheel landing compared to a full stall landing.

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There are (at least) two distinct ways that wheel landings are taught.

- One school of thought is to "pin" the plane on the ground when the main wheels touch by moving the stick forward an inch or so.

- The other school of thought is to trim the plane slightly nose down for a slightly faster speed, but then hold back pressure to maintain your normal final approach speed, and then when the mains touch, release that back pressure.

I prefer the latter method, but both work. Try them both and see what works best for you.

Once you are really comfortable in the aircraft you can graduate to a short field wheel landing where you bring it in low, flat and slow for a tailwheel low wheel landing, where you also slow the aircraft with braking as soon as the mains touch to keep it on the ground along with back pressure to allow maximum braking as soon as possible. There's a fine line between maximum braking and nosing over to a prop strike.

The biggest mistake I see pilots make with wheel landings is increasing the final approach speed and flying the aircraft on at an excessive speed. That just aggravates the directional control issues and requires you to keep it straight longer. In the end, you still eventually have to slow enough to lower the tail when the rudder stops being effective in order to get the tail wheel on the ground to steer with the tail wheel. In other words, it's ok to use some power to flatten the glide angle angle at touchdown, but don't increase the speed.

 

[Bob Turner]

That disagrees with your earlier comment about faster approach speed.

I teach wheel landings out of the same approach for a three point. In the beginning I teach adding power in the flare, but later I teach just interrupting the flare by flying it on at idle.

By the way, all Decathlon landings are "wheel" landings. Do not even attempt a full stall landing in a Dec - way too much force on the mains.

 

[BB57]

Context matters and you seem to want a one size fits all answer. I don't live on a planet where that works.

Practice wheel landings aside, there are not all that many circumstances where I find a wheel landing to be necessary in the real world. Living here along the east coast, I see even less need for a wheel landing than I did living out west. I learned to fly in western South Dakota where the average wind velocity is 20-25 mph depending where you are. That's "average". Flying in higher winds, and in particular in winds with higher than average peak gusts is common. In addition, the winds are often not just gusty but also variable over a 30 or so degree arc.

That combination of very gusty and variable winds can create a situation where a wheel landing is useful to ensure the aircraft doesn't come off the ground after you've touched down if you encounter a 10-15 kt gust and/or give you a bit more control. In that specific real world case you are also going to increase your final approach speed by half the gust factor, which will mean a slightly higher approach speed in a real world situation where a wheel landing makes more sense than a full stall landing.

*IF* you opted to make a full stall landing in wind conditions that included a significant gust factor you'd also increase your approach speed accordingly, and unless you were an idiot, you'd also flare and bleed of the excess airspeed just inches over the runway so that if the wind shears you'll settle onto the runway gently, rather than drop onto it from 2-3 ft in the air. Practically speaking if I settle onto the runway due to wind shear during an intended full stall landing, I'll release the back pressure and convert that intended full stall landing into a tail wheel low wheel landing and then move the stick forward to keep the tail off, in order to prevent the aircraft from becoming airborne again if the wind gusts again. The point here is that the approach speed for each type of landing is based on the wind, not the intention of a 2 versus 3 point landing. But in the real world, if you need a wheel landing, it'll be in wind conditions with a gust factor that warrants a higher airspeed.

The general concept is that you should not be selecting an approach speed that is faster for a wheel landing than you would for a full stall landing, just because it is a wheel landing. The general idea is also that there are only a few specific situations where a wheel landing makes more sense than a full stall landing.

The caveat/problem is that many students learn wheel landings starting with a higher than normal airspeed and some additional power in order to flatten the glide angle and give them more time to "feel" for the runway. By extension, having a student fly nearly the entire length of a 7000 ft runway 6" off the runway at 60 mph or so can be a useful method to help develop that feel. However, once they've developed a solid understanding of the visuals and can quickly find the correct height and precisely arrest the descent rate to put the wheels smoothly on the runway, the need for that long, flat portion of the wheel landing dissipates. Yet students continue to do what they were taught and continue to make wheel landings at faster than necessary airspeeds, just because they are making a wheel landing.

We're on the same page with this caveat, given your comment that you teach with power initially and then fade to power off wheel landings (where the pilot is using the energy of the aircraft to arrest the descent).

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I have heard that the DC-3 and the Beech 18 should be considered to be wheel landing only aircraft. I've also heard pilots comment that the Globe Swift can be inconsistent in a full stall landing and that wheel landings are a better default choice for a Swift. However, since learning to fly in 1982 (and in several years hanging out as the airport kid prior to that) I have never heard any pilot say, until today, that a Decathlon or Super Decathlon cannot be landed three point.

The stall speed of a Decathlon is literally 2 kts faster than a Citabria, the weights are very close, the Decathlon gear is just as strong, and the Decathlon airframe is stronger. With the exception of the 7GCBC, the CItabria also lacks flaps like the Decathlon.

To be fair, the Decathlons shorter wing and less lift efficient airfoil, will produce a bit steeper descent angle, so you'll want to carry a bit more speed into the flare (70 mph, rather than the 65 mph you'd use in a Citabria) and depending on weight you may want to leave a little power on (900 rpm -1200 rpm) to control the descent rate/angle, but a full stall landing is totally permissible and is in fact normal.

I'm sorry but weighing all the evidence, including the POH for the Decathlon, I have to put your comment in the "Unmitigated BS" category. I have no idea why you think that's the case but I am really interested to hear your explanation.

 

[Bob Turner]

Okay. I have flown Decathlons since before you learned to fly, and have owned one since 2003. I have owned the same J3 since 1962, and fly it daily. My very first flight in a Dec won me 3rd place in an IAC event. In the last week I have logged over 50 landings, and I am no longer current in nosewheel aircraft.

You are correct that 70 is a good approach speed, but the Dec can safely approach at 65. Its wing, as you point out, is shorter and symmetrical, but don't forget, its angle of incidence is lower. When it stalls with the tailwheel on or near the ground, power off, the mains are nowhere near the ground, and when they come down it will be in a bone crushing crunch.

A much better and safer landing is a 3-point power off wheel landing. You simply rotate to the 3-point attitude and stop pulling back until all wheels roll on. Then ease the stick back into your lap.

You are probably more skilled at midwestern winds than I - I won't even taxi out if the wind is greater than 24 kts, and my direct crosswind limit is 20. But that has nothing to do with the stall attitude of a Decathlon.

 

[BB57]

So you're saying the Decathlon needs larger wheel pants to cover larger 8.5x6 tires, or maybe 26" tundra tires?

Seriously though, I can see where you're coming from with the angle of incidence issue slightly increasing the tail low attitude of a full stall landing for a Decathlon. However, I don't hear reports of damaged airframes because of it.

Personally, we opted to spend more than we originally planned and went with a 7 KCAB in part because it's a good compromise. It doesn't have quite the short field potential of the 7 GCBC, but it cruises a couple kts faster, and it has some limited inverted capability. On the other hand, the 7 KCAB doesn't hold a candle to the Decathlon in inverted flight and outside maneuvers are just not its thing. However it's a more versatile aircraft in terms of being capable of both positive g aerobatics and short field/soft field landings than a comparable operation and maintenance cost 150 hp fixed pitch 8 KCAB.

And again in all seriousness, it's no big deal to put 8x6 or 8.5x6 (with an STC) tires on a 7 KCAB to bias it a bit more toward soft field performance.

 

[Bob Turner]

I think the reason you don't hear damage reports is that Decathlon owners learn to do 3 point, but not full stall, landings. It only takes one full stall landing in that bird to convince you you ought not do that. One really hard landing doesn't usually break a Decathlon, but you will note they have gone to NAS bolts in there - 167,000 psi bolts!

 

[BB57]

I think the reason you don't hear damage reports is that Decathlon owners learn to do 3 point, but not full stall, landings. It only takes one full stall landing in that bird to convince you you ought not do that. One really hard landing doesn't usually break a Decathlon, but you will note they have gone to NAS bolts in there - 167,000 psi bolts!

I genuinely curious, why three point if it's not full stall, and what happens after the touchdown?

As you know, in a full stall landing, the aircraft is at the critical AoA when the aircraft lands, the gear compresses a bit, and/or the main wheels drop a few inches to the runway. Both lower the AoA below the critical AoA so that the aircraft is done flying, and you've got the tailwheel on the ground where it starts to have an increasing amount of weight on it, particularly as you're also holding full aft stick, where it starts to add both drag and directional stability. Short of a significant increase in IAS (i.e. a big wind gust) that is sufficient for the aircraft to fly at that lower AoA, the aircraft will continue to be done flying.

Similarly, in a wheel landing the AoA is reduced by relaxing back pressure/adding forward stick, which has the same effect of ensuring the aircraft is done flying. In fact, in gusty wind conditions, the AoA is significantly reduced to ensure the aircraft stays on the ground even if it experiences a 10-20 kt gust. You still have to navigate through the range where a combination of AoA and a gust induced increase in IAS could still lift the aircraft off - while keeping the aircraft straight on the runway with decreasing rudder effectiveness. However with the ailerons against the stops, by the time you start to lose rudder effectiveness, you're slow enough that you can firmly lower the tail and apply full aft stick and effective yaw control from the tailwheel.

However, a three point landing above stall speed is just that, and lacks the AoA reduction qualities of a full stall landing or a wheel landing. You are effectively still flying in close formation with the runway until you lose sufficient airspeed so that the aircraft can't lift off at the AoA it has in a 3 point attitude. Absent any control inputs, a gust in that condition will lift you off the runway. Consequently, I wondering what you do right after you touch down:
- Does the stick go forward to reduce AoA (a tail low wheel landing);
- do you wait for it to slow below the stall speed at that AoA before adding aft stick to put weight on the tailwheel;
- do you apply a judicious combination of brakes and back pressure to get below that critical airspeed quickly (similar to what can be done in a short field situation with a wheel landing, where you want to put weight on the wheels to get maximum permissible braking without nosing over, as soon as possible); and
- when do you decide that the juice isn't worth the squeeze and just do a wheel landing?

 

[Bob Turner]

I answered some of that above. Before I answer the rest, how many Decathlon landings have you done?

 

[BB57]

I answered some of that above. Before I answer the rest, how many Decathlon landings have you done?

I'm not here to argue Bob, just to get your perspective and learn from your experience, not just the what but also the why, in a bit more detail. If you're not wanting to offer it, that's fine.

 

[Bob Turner]

You called bullshit. You are entitled to do that if you have a hundred Decathlon landings.

I bring the aircraft over the fence around 60, then establish a three point attitude and fly it on to the ground. The stick then comes all the way back, and I let it roll. Takes a thousand feet. It is not a short field aircraft, and the brakes are identical to my J3 brakes so I stay off them.

I do one landing on the mains each pattern session. Takes more finesse than a C-180.

I have averaged three landings a week since 2003. Aircraft has been down since January for maintenance. That is over 2000 landings.

 

[Big Ed]

Been working on dialing in the numbers on my new-to-me Super D. Trying to slow my approach down, but it sinks like a rock when I go below 80 at idle. The Super seems to glide much worse than my old 150 HP Decathlon CS. I'd like to approach at 70-75 but the bottom drops out..

 

[Bob Turner]

Doesn't it come down like a rocket at idle above 80?

Going out for six slow rolls tomorrow - I will do an approach at 70/idle and report back. I normally keep a little power in to avoid those loud pops (no baffles in muffler).

 

[DanO]

I am still a relative beginner with about 30hrs and probably 50 landings in my Super D. Only 3-point landings so far. I find it harder to land pretty than the J-3s, T-Crafts, Champs and Steamans that I've flown. My current technique is 80 on final, near 70 over the numbers, reduce power to idle if it is not already there, and hold it off until the stall warning sound is steady. Stick fully back at/after touchdown. Seems to stick pretty well most times.

 

[Bob Turner]

I can’t do that. The first time I tried the “Cub” style 3-point landing in my Dec, it stalled with the tailwheel on the ground and the mains a foot above the ground. Ca- runch! I use a 3-point wheel landing most of the time.

Today I did ten J-3 landings and four Dec landings. I purposely paid attention to airspeed and descent angles - at 70 and idle, the angle is more or less like the J3 at 60. You need to be careful in the flare, since if you slip below 70 before the flare it will quit flying rather quickly.

If you want a shallower angle, just carry a teeny bit of power - at 70.

I tried one at 65, and one at 60. Sixty is too close to stall for normal operations. Sixty-five is ok, but you will need a bit of power to arrest the sink rate before the flare.

The only time I am above 70 on short final is when simulating an ILS to 100 feet. Eighty is just too fast. Opinion.

These fine aircraft are not Cubs, and decidedly not short field airplanes.

 

[Big Ed]

I'll work on it some more at 70-75. Haven't had problems at 80, but above that floating and ballooning get bad, so I'd like to get slower.

I have always landed full stall. In my old Decathlon CS that consistently resulted in a very smooth 3 point touchdown. In my new-to-me Super D the tail sometimes touches first and I get about 6 inches of drop on the mains. Not so much force to be concerning, but also not always "smooth". I will probably refine my technique by stopping the pull just a hair before full stall and flying it on.

 

[Bob Turner]

Make sure your airspeed is accurate. Try a power off stall - see if it breaks around 54. If so, work on 70. Eighty is just too fast. To go from 80 to tailwheel touchdown in the flare takes 700 feet.