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Super Cub Final approach speed?

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.


Agreed, and I'll add that this is because you are flying a wing that is disproportionately modified when compared to it's tail, and expecting it to stall in a similar fashion to what we are used to (like a cub). I suspect if you had more tail, you could very readily get the wing to stop flying. Not a bad thing when you need it.

Take care, Rob
 
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.


Take care, Rob
Dark air has no lift!
 
Agreed, and I'll add that this is because you are flying a wing that is disproportionately modified when compared to it's tail, and expecting it to stall in a similar fashion to what we are used to (like a cub). I suspect if you had more tail, you could very readily get the wing to stop flying.




This was my second flight with my bigger tail, that has about 20% more elevator surface than stock PA-18, being 3" wider and 3" deeper per side. I will not built another one soon. I will try some power on landings next time






i1YwLm7KuFXr6EyEH21X1ryKY_gvm7Fw4fUM-TAmR4JimDw6h7br4JNXOpqWocBTW2skECrrcOoZ4L3X39kDBn238Cyanz2onToASTc2kVY7VKQWwOu-Lst7u_4m3AcmpTal70vSVLID7HXZe0zdIY7VwPlMpcUKYeCJ70QRzwO3m00jV20-TnSVDuHa5yh5HBaPXgCsV7U6c2rxxMg5D4aatV_ZsN7cXM1_l4k09__ujNJH7vRMsXCzrCiVEqLNN7_PRiUU1gt3JxotohHq093u1hBmd1PTC9StLz84JuecvmYFcN_3Xn7_NagtDbzokMoOP6w3hCEz6paiTpR1Xfhc4R9xuyJ8AJrpCsrrAWv9kc7MgSbtMZH2Ow_dXxEuNvU8PJGAOPfnGAhF3JzS6YUq0uyGRfp3dVqyclkOa_PmIsVf5e5Iw7-AMfsIf-U3vxWk7XSHLW5h1CdTksJwGMLD6hTQMSrK1jnyfEXt1YuiKSQ41nT5eoEeNeJnOUr_71fMW_tRF1mDAnembRXNAs_9cK6nzmRQ8fXkXmao3LCOmcb7ZJRnnVoiwNACI2PvSdRfqsv2b9dalW9vcKdpS4McXdusDHgkSxokzmkURS_YtpZ--313lTG7idHG7aQC_SkNsbYx1dYjbFWJLgUC1jBCzhz-0NQ=w800-h600-no
 
This was my second flight with my bigger tail, that has about 20% more elevator surface than stock PA-18, being 3" wider and 3" deeper per side. I will not built another one soon. I will try some power on landings next time

i1YwLm7KuFXr6EyEH21X1ryKY_gvm7Fw4fUM-TAmR4JimDw6h7br4JNXOpqWocBTW2skECrrcOoZ4L3X39kDBn238Cyanz2onToASTc2kVY7VKQWwOu-Lst7u_4m3AcmpTal70vSVLID7HXZe0zdIY7VwPlMpcUKYeCJ70QRzwO3m00jV20-TnSVDuHa5yh5HBaPXgCsV7U6c2rxxMg5D4aatV_ZsN7cXM1_l4k09__ujNJH7vRMsXCzrCiVEqLNN7_PRiUU1gt3JxotohHq093u1hBmd1PTC9StLz84JuecvmYFcN_3Xn7_NagtDbzokMoOP6w3hCEz6paiTpR1Xfhc4R9xuyJ8AJrpCsrrAWv9kc7MgSbtMZH2Ow_dXxEuNvU8PJGAOPfnGAhF3JzS6YUq0uyGRfp3dVqyclkOa_PmIsVf5e5Iw7-AMfsIf-U3vxWk7XSHLW5h1CdTksJwGMLD6hTQMSrK1jnyfEXt1YuiKSQ41nT5eoEeNeJnOUr_71fMW_tRF1mDAnembRXNAs_9cK6nzmRQ8fXkXmao3LCOmcb7ZJRnnVoiwNACI2PvSdRfqsv2b9dalW9vcKdpS4McXdusDHgkSxokzmkURS_YtpZ--313lTG7idHG7aQC_SkNsbYx1dYjbFWJLgUC1jBCzhz-0NQ=w800-h600-no

It'd be interesting to compare the enhanced lift of the larger tail surfaces to what you gained on the longer wing with bigger flaps, slats and all the enhancements. Really neat airplane for sure.
Dark air has no lift!
My excuse on a regular basis ;-)
 
Oli, notice that the two leaders in the enhanced wings category, Mackey and Backcountry, have both evolved into extended airframes along with oversized tail feathers?
 
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Oli, notice that the two leaders in the enhanced wings category, Mackey and Backcountry, have both evolved into extended airframes along with oversized tail feathers?

I did not knew they now had extended airframe.


Mine is only a modified PA-18 with slats, bigger flaps, bigger tail, and a few other small modification.





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Backcountry Super Cub.jpg
 

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My tail is moved back 20". Slats move the CG envelope aft 2". Adding weight aft is important to improve control responsiveness. I assume weight would be even more important with a standard length tail.
 
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The downside of extending your airframe/large tailwheel/large tail spring is now you will hit your tail even sooner on landing and when you try to rotate on takeoff. I normally run a 4 leaf tail spring with wide fork for everyday use. When I play at fly-in I change to 3 leaf and reg tailwheel. I have a stock wing and trim nose up so flair is not an issue with me. If you can make it work with a stock length fuselage I would stick with it. But once you add a big heavy motor and heavy modded wings I could see the need to balance things out.
DENNY
 
Oli
Look up the MAF landing technique. They release the stick/yoke flair back pressure some just before the wheels touch this allows the tail to come up and not hit first.
DENNY
 
Domino....Domino...Domino, When slats are added most pilots will quickly realize they now have a wing that out performs their tail. At least the ones who fly at the margins. Mine sure did!
 
Oli
Look up the MAF landing technique. They release the stick/yoke flair back pressure some just before the wheels touch this allows the tail to come up and not hit first.
DENNY

When watching brlp’s videos you’ll see Loni demonstrate that tech. On most all his landings. Pretty cool.
 
Oli
Look up the MAF landing technique. They release the stick/yoke flair back pressure some just before the wheels touch this allows the tail to come up and not hit first.
DENNY
Similar to the technique for landing in rough water in some flying boats which reduces pounding.
 
Oli
Look up the MAF landing technique. They release the stick/yoke flair back pressure some just before the wheels touch this allows the tail to come up and not hit first.
DENNY
But the mains will still slam down, perhaps even more so.
 
Look up the MAF landing technique. They release the stick/yoke flair back pressure some just before the wheels touch …..

Here's the crux of an article Bill White wrote about the MAF wheel landing technique in the C180.
There's been a few versions of this article posted online, with some slight revisions over the years--
the 3 or 4 seconds of slight back pressure at 20' AGL to arrest the sink rate being one of them.
I don't necessarily do it exactly the way Bill White describes,
but IMHO his technique is a good place to start for noobies, and worth reading for the more experienced.

Bill White on wheel landings.jpg
 

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Gordon
That could be a good thing. Energy has to be dissipated somehow, the more the tires/shocks absorb the faster you can stop. Getting ready to prep some metal I will try to get back to this latter.
DENNY
 
Yes, but vertical forces do not contribute to the negative work which is required to reduce horizontal velocity component.
 
But the mains will still slam down, perhaps even more so.

The mains won't slam down unless you don't do it right, which of course does happen on occasion. :???: The way it was taught was certainly not slamming it down. It was, however, a firm, tail low touch down so that you could get good braking right away.
 
The mains won't slam down unless you don't do it right, which of course does happen on occasion. :???: The way it was taught was certainly not slamming it down. It was, however, a firm, tail low touch down so that you could get good braking right away.

Well, first off, I rarely do landings just right - - -

But given that, how is it different to put an upward push on the tail with elevators, as compared to with the tailwheel?

Sounds like I have some technique to learn??
 
Yes, but vertical forces do not contribute to the negative work which is required to reduce horizontal velocity component.

Gordon we like pictures...can you draw up a vector diagram that shows and explains what you just posted? My physics instructor in Sitka 54 years ago said if you can't figure it out with math or logic draw it out. Dr. Skinner was a WW2 ground flight instructor so I think he was on to something simpler.

Gary
 
Gordon
I would say that it is all about energy management the direction does not matter. Somehow you have to dissipate it all before you can stop. Landing hard, hard left then right brake to wag the fuselage, or even a ground loop at low speed will do the job of getting rid of energy. The MAF technique works great in normal landing, makes it effortless to roll it on the mains. The reason I recommended it was to prevent damage from a tail first landing. Even a stock cub can slow and flair to the point that the tailwheel is a foot or more below the mains. The issue is to get the mains on the ground before the tail hits. Just pulling power lets the entire plane settle and you hit tail first. If you just pull back and stall one wing will drop and tailwheel will not hit the ground, if you do it right the wheel/gear will absorb it before the wingtip hits and you will bounce to the other side. Great for burning up energy but very hard on the gear. Leaving power on and releasing the flair will let the tail get above the mains before they touch if done right. Getting rid of the flaps also helps the front drop. The problem as you know is making it all work/ hitting you spot/ without damaging you plane. Most of the stuff I am talking about here is not for everyday operations. It is for trying to stop very short!!
DENNY
 
Well, first off, I rarely do landings just right - - -

But given that, how is it different to put an upward push on the tail with elevators, as compared to with the tailwheel?

Sounds like I have some technique to learn??

I think the difference in the technique is that there’s a mini-flare right before the touchdown to arrest vertical sink. The forward push is probably timed so that it changes the attitude to get the mains down and the tail wheel protected, but not high enough to allow a large sink to develop.
 
As is obvious from this discussion, it's really difficult to describe "how to land an airplane", which is why we do flight training.

The tail low wheel landing is actually a pretty simple maneuver, and it's primarily aimed at two goals:

Land the airplane on the mains.

Get the tail up so the pilot can SEE where he or she is going with the airplane.

Landing on the mains protects that itty bitty tailwheel from damage.

Landing in very nearly a three point attitude, as in tailwheel an inch off the surface at the touch, allows you to land the airplane at virtually the same speed as you would in a three point, but protects the tailwheel and gets the nose out of the way so you can see where you're going.

I recommend to folks starting to use this technique to roll in some nose down trim prior to touch. That'll require a bit more nose up elevator (back stick) input. As you touch, relax that back pressure, then move the stick forward. The slight nose down trim will tend to help stick the landing at the touch.

Then you just have to move the stick/control yoke forward to get the tail up to see.

For us short folks, seeing over the nose is touch in most airplanes. In a 180/185, I can't even see the airport in the three point attitude. And, I see no point in wearing out wheel bearings and brakes doing 70 mph touchdown wheel landings.

MTV
 
I do understand and agree with what you're all saying re visibility and protecting the tailwheel.

But braking distance gets simple from the perspective of fundamentals. The ONLY thing that will reduce the airplane's forward speed is force directed opposite the direction of motion of the plane. Given that, the greatest possible (non-aerodynamic) braking force is with the wheels on the ground, with the greatest amount of weight on them. So bouncing, excess aerodynamic lift, and excess speed all unnecessarily increase braking distance. I can see how good shocks, like the TK's Stewart mentioned, could be very beneficial by keeping the tires on the ground.

To me, very slight tailwheeel first, so that there is no bounce, and dump flaps is optimal. However - - I do not land on real rough surfaces. If I did, I'd need to practice staying up on the mains.
 
If you guys want to reminisce a bit, take a look at this older thread. It got sidetracked a bit onto nose down or up trim (without really discussing the big difference using it with a adjustable stab vs a trim tab), but it all relates to this thread. I like a later post from "spinner", talking about landings and take offs with a nose down _stablizer_, (cub trim), which he felt made a noticeable difference to him. I've heard similar stories from other guys that I try to learn from. Tail carries more of the load, thereby helping to unload the wing a touch.

http://www.supercub.org/forum/showthread.php?45153-A-little-help-with-landing-technique

I've not gotten consistent with it yet, but when done right, the feeling/impression/resultant roll out for me was always the best with a steep approach angle, nearly mushing it all the way down. The part needing practice of course was arresting the descent rate at exactly the right time to plant the tires without bouncing. Again best done in consistent wind or no wind. But with 29" Airstreaks, the rollout for me was always shorter than a more traditional flatter approach and relying on braking power. I had bungee's, but it seemed if you had 31's and shocks you could really bring it home short.

I see this as simply geometry. Steep approach angle provides the same flying speed, but with a more unloaded wing in a downward vector instead of a forward vector, therefore the forward groundspeed is less than a more traditional approach. The old adage about the visual perception of the approach being a "walking speed" starts to really hit home. Upon ground contact and without bouncing, roll out is very short.

Without the forward movement, it's just maintaining perfect control and arresting the descent without planting deep or bending parts up around the wings. I would't even attempt it in a Trike, or traditional metal airplanes. But in a rag/tube bush-type airframe it really is a noticeable difference to me.

pb
 
Steep approach angle provides the same flying speed, but with a more unloaded wing in a downward vector instead of a forward vector,
Not quite correct. In any steady-state, i.e. constant velocity condition (constant airspeed and vertical speed, not-turning), including descent, the lift exactly equals the airplane weight, and the drag exactly equals the thrust.
 
Gordon, yes I believe you're correct. I should have thought about it, as it's the perception that it has changed. The idea that you're simply floating down vertically instead of flying forward gives the impression that somehow you're lighter.

Cameron, those video's are just what I was talking about. When I missed hitting it just right, I would usually have run out of airspeed/elevator to arrest the descent as much as preferred. It's that fine line it seems.
 
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