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Super Cub Final approach speed?

A plane will fly slower in ground effect, maybe substantially slower. So putzin around at altitude trying to imagine a slow approach is actually kind of funny. First of all, the plane isn’t in ground effect, and, the visuals aren’t there, it’s just plain imagination. Find a nice long runway on a dead calm morning and air taxi the thing up and down as low as you can as slow as you can. Use flaps. Use tiny increments of power as needed. Lots of fun and great practice. When you’re right in the groove steal a glance at the airspeed. Then GPS. But what ever those numbers are won’t matter, just background info. A practised up Pilot current on type won’t need those numbers close in.
 
The reason to do it at altitude is for the approach. You want to get comfortable slowing the plane down before you get into ground effect so you are not dragging it in getting rid of excess speed. I would say the number one thing that help me slow down was spin/stall training I highly recommend it for every pilot especially if you want to do off field or STOL work.
DENNY
 
mvivion said:
The tail low wheel landing permits you to touch down at essentially the same speed as a three point landing, but protects the tail.

And, a wheel landing allows you to see where you're going.

MTV
Click to expand...
Both at the same time...?

If I'm dealing with any kind of wind, I'll carry a little extra speed and plant it with a bit of purpose, mains first. If it's a typical dead calm morning/evening (common around here) I'll use it all up at touchdown. With zero throttle, I get a 3-point touchdown concurrent with the stick hitting the stop. Those $3700 tires appreciate it.
 
I recall the time when the FAA feared large tires might allow the plane to stall during a tail low takeoff or landing. Resisted FA them. Critical AOA and so on. Wonder what happened to that theory?

For a Taylorcraft in 1974 I had to demo a 3-pt takeoff and power off landing on 8:00x6 before they were field approved. Then I bought a PA-18 with 25" Goodyears that were safe. Now we have 35's used every day.

Go practice and have fun.

Gary
 
BC12D-4-85 said:
I recall the time when the FAA feared large tires might allow the plane to stall during a tail low takeoff or landing. Resisted FA them. Critical AOA and so on. Wonder what happened to that theory?



Gary
Click to expand...
I remember reading about that. There were concerns with the tires blanking the tail. I think the fear was the blanking would cause the nose to drop when the elevators got in the slipstream of the tires. There were spin recovery concerns along those lines too.
 
I mentioned the tire thing as part of this thread's question...do large tires affect slow approach speed and behavior? I don't have much experience with the largest sizes. Are they a control factor for those that land slow on the back declining side of the lift curve?

Gary
 
Well, they theoretically reduce the ability to flare, due to the polar moment. As the aircraft flares/rotates on its lateral axis, those heavy tires swing forward/up and effectively shift the CG forward. It SHOULD take more stick to get a given amount of flare under given conditions.From a practical standpoint I can't say that I've noticed it (31's). YMMV.
 
Penny Nixon was contracted by DOI and the State of Alaska to flight test (He is a DAR) Super Cubs on various tire sizes in an attempt to put those FAA “concerns” to rest.

His report is comprehensive and a good read. Basically, he found that the only significant negative effects of big tires were increased weight and a slight decrease in speed for a given power setting. If I recall he tested various tire sizes up to 36 inch Airwheels.

After that study was provided to the FAA they shut up about the effects of big tires on Super Cubs.

MTV
 
They reduce your crosswind capability somewhat, if you run them soft. And while I have spun 26" tires, you will not catch me spinning floats or 31's. Just chicken, I guess. Never noticed much difference on landing, but getting them in/out of the hangar? No longer strong enough.
 
A spin-off from the tundra tire tests (pardon the pun) was the FAA's interest in wing rigging on Cubs and specifically wing washout. That became their new priority once the tundra tire-moose stall link was disproved. I'm not 100% sure of the timing but I believe that led to Gordon Mandell's Piper wing rigging paper that the FAA published. That was fuel for a fight between Atlee and Gordon as well as among Cub guys, including here as I recall. If you're having a discussion about landing speeds and exploring differences in opinions between different Cubs? Add wing rigging to your list.

There are guys who believe a some Cub accidents may be linked to guys familiar with their Cubs going to 35" Bushwheels. There's no question that the 35s are heavy and change the CG. The question is how guys adjust their SOPs with the more forward CG.
 
I have several friends with the 35's and they love them, they do note that it takes a bit for the tire to spin up to speed. Good thing if you are trying to stop short, bad if you are not ready for it.
DENNY
 
BC12D-4-85 said:
I recall the time when the FAA feared large tires might allow the plane to stall during a tail low takeoff or landing. Resisted FA them. Critical AOA and so on. Wonder what happened to that theory? ...
Click to expand...

They've moved on to just resisting ALL field approvals.
Progress.
 
Maybe you ought to hook up with a cub guy from nearby, or on here. I don't think this guy's doing you any favors.
he may be a tail wheel guy, but he doesn't sound like a CUB guy.
 
Lots of ideas, opinions and techniques. I'd never suggest mine is best, or right. Everyone has to be comfortable.

I bought an experimental. It's got 4" wider fuselage, and the extra 4' of wing. I'm learning by doing.. and getting more comfortable approaching at a 'yeah, that's about right' nose attitude.

I added the gap seals, and have a lot more elevator authority down slow.

Numbers... heck.. the A/S is in knots.. and hardly reads. I did some touch and gos on skis the other day. I had the power set at 1500, and was just hopping along down the river in ground effect.. A/S never got much above 30kts.. seemed to fly at around 25 indicated.

I'm taking a stab that the extra 4' of wing changes a lot of the numbers.

JP
 
PerryB said:
Both at the same time...?

If I'm dealing with any kind of wind, I'll carry a little extra speed and plant it with a bit of purpose, mains first. If it's a typical dead calm morning/evening (common around here) I'll use it all up at touchdown. With zero throttle, I get a 3-point touchdown concurrent with the stick hitting the stop. Those $3700 tires appreciate it.
Click to expand...

Landing off airport, and sometimes on airport, it’s nice to be able to see what your tires are about to run over. It’s also nice to protect that precious little wheel in back. Those are the arguments for tail low wheel landings. Gives you the benefits of both.

But, if all you’re doing is landing on pavement, why wear out a set of “$3700 tires” in any case?

MTV
 
bob turner said:
I do a lot of stalls. All the Cubs I fly can be stalled a foot above the runway. With power they can be forced to run down the runway on the tail wheel. One famous Super Cub was known to drop a wing in the flare. No aileron control on that bird; rudder saved us. I have had a stock Super Cub drop a wing in the flare - once. Good thing we were just six inches up.
Click to expand...

Are the airplane wing stalled or elevator control stalled?? I never been able to make a difference or it is the same??



Like is the next video. What do you think is happening??

 
As you slowed the sink rate increased. Neither the wing nor the elevators indicated an approach to a stall. Had it been a stall the nose would have pitched down.
 
How can I do a full stall landing, that is the question..??

Or do I want to do a full stall landing??
 
You don't really want to do a full stall landing. Just one at minimum speed with all the wheels touching the ground at the same time. With a full stall landing your control effectiveness could be lost. Judging by your videos you are doing a good job. A full stall landing with your plane would likely have you landing on the tail wheel with the main wheels still high in the air. When that happens, the tail wheel touching will lower the nose, reducing the lift on the wing and increasing the rate of descent. This increases the impact on the main gear with the potential to have an extreme pitching forward. One the tail wheel touches the ground your elevators can no longer keep the nose high enough to prevent the wing from stalling.
 
You’re doing a fine job flying your cub, I can tell from your videos. All these posts on cub approach speed can lead a fella to wonder “do I know what I’m doing???” And, “am I missing something, this is more difficult then I thought!!” Nope. It ain’t that complicated. Yep, you know what you’re doing. Keep on flying, you could teach the course.
 
Don't beat up the tail by landing that end first. It gets expensive and is unnecessary unless you have long Storch gear to compensate. What takes longer distance for your plane...landing or taking off?

Gary
 
BC12D-4-85 said:
What takes longer distance for your plane...landing or taking off?

Gary
Click to expand...


Landing usually take more distance in my case.

If I can land somewhere, takeoff will be no problem (with same load)

I also always found takeoff easier to execute...
 
That 's an interesting balance - being able to land shorter than a takeoff. Deep soft snow helps of course, but I have no experience with a plane like yours. If you takeoff in a certain attitude can you land at that same deck angle and still be shorter? Or does it take high nose up riding on power and the flaps and slats to make it happen?

Gary
 
Olibuilt said:
Are the airplane wing stalled or elevator control stalled?? I never been able to make a difference or it is the same??



Like is the next video. What do you think is happening??

Click to expand...



It looks like as you are descending and slowing down, your elevator starts to significantly loose its downforce compared to the wing at around 3 seconds. This causes the airplane to pitch to a more level attitude. You apply short bumps of tail down elevator with little effect until you apply steady and increasing tail down input. This causes the tail to drop. It looked like the landing was close to full stall. I measured the angle of the bottom surface of your wing and it was around 15 degrees. Elevators are flat surfaces and have a large gap at mid span, which cause them to stall at a much lower angle than the wings - especially with no propwash. The further nose up you are trimmed the LESS likely the elevator will stall.

I have always been able to get my airplane to a higher angle of attack by continuously bringing the nose up, than by dragging the airplane in at a flat angle and then trying to flair. I taped a digital level to my dash and I could never get it to as high of an angle of attack, with an aggressive flair.

Riding with someone who has that perfect balanced landing technique is amazing. No matter what pattern they fly, the wing angle hits its maximum just as the mains or tailwheel touches. It's feels like the last note on a song. When they purposely stall it on from 3 feet; it seems like the song has an extra beat.

Nice work and sweet airplane.

Jonny
 
Bill Lentsch from Fairbanks was one of those Cub pilots that could make a landing. Riding with him was an experience. Wish I had a video today. He'd remove his headset and listen for the music on landing.

Gary
 
A pretty common error in this thread and others is to equate an aircrafts angle relationship with the earth as it's angle of attack. Using a digital level, or inclinometer doesn't really tell the story of what a wing is doing. I am reminded of that at night on a regular basis as the stall warning light comes down while the aircraft is on at leas a 15° nose down attitude in relationship to mother earth.
I am of the opinion that this where people run amok when they assume slats / slots only work with the nose pointing at the moon. They work just fine without the nose standing straight up, they just happen to like a steeper approach to enjoy a flatter attitude. That steeper approach is often uncomfortable for a fixed wing pilot who is used to flying it on fairly flat, but probably right at home for a fling winger who is used to steeper yet.

Take care, Rob
 
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