Kent's Long-EZ project

[Voidhawk9]

The nose-gear on these machines always seemed to be a weak-link, particularly for the Cozys. Of course, heavily loading it, especially under braking, will tend to push the geometry where you don't want it to go.

[Kent Ashton]

2 hours ago, zolotiyeruki said:

I saw that one too, and it looks like 1) he's holding the nose off for a long time, and 2) it looks like there's not a lot of friction in the pivot.

Hard to say but maybe dropping the nose was enough to initiate a shimmy then hard braking aggravated it.  I have felt it once or twice.  I tightened the friction and that helped.  Castoring nose gear systems do strange things. 

A story I might have told before:  F-4s flew for years and blowing a tire would often result in running off the runway.  We just assumed it was drag from the blown tire pulling the airplane.  Then a smart young Captain investigating one in the New Orleans Guard determined that the real reason was that a blown tire lowered the wing enough on that side to cause the F-4's castoring nosewheel to steer the airplane to that side--like trying to push a shopping cart on it's side.  Drag from a blown tire was not substantial.  The flight manual said with a blown main tire to engage hydraulic nose gear steering but did not explain why.  The New Orleans pilot had engaged the nosewheel steering but momentarily released it to lower the hook and pull the drag chute.  Each time, the skid marks showed that the airplane had made a hard jink towards the blown tire.

[zolotiyeruki]

I don't recall if you're in the Cozy email group, there's a pretty thorough discussion of Russ' nose wheel shimmy there as well.

[Jon Matcho]

...and also on the Canard-Aviators mailing list.

[Kent Ashton]

A friend of mine had a hard time starting his EZ with battery in the nose.  I forgot I had made one of these 4-wire ohmmeter testers so we ended up changing his starter cables out to bigger and heavier cables.  It seems to have solved his problem but I suspect taking some measurements with this sensitive ohm tester from the great Bob Nuckolls might have found some high resistance in the circuit.   He shows that with pretty ordinary resistances in a starter circuit, a 12.5V battery may only deliver 7.46 V at the starter.

http://www.aeroelectric.com/articles/grnding.pdf

[Kent Ashton]

Just reading about a guy who lost his engine at 9500 feet and landed 100 feet short of a runway doing a fair amount of damage to his Cozy.  There were about 70 comments praising him for a job well done (he wasn't injured).  I would say he is lucky but this was not a good outcome. 

While acknowledging that I could be sitting in a field myself next week after the same sort of mishap, we should look at this one further.  He said his intended runway was on the edge of his Foreflight glide range indication so that made it tougher.  Foreflight says "[Glide Advisor] Uses your aircraft’s glide ratio, current GPS altitude, surrounding terrain, and winds aloft to present a ring showing your glide range."  (pic)

IMO gliding a Cozy straight in to a distant airport is fraught with difficulty.  First, we are trying it with the prop stopped or worse, windmilling, so we probably aren't used to the steeper glide.  Next, it is very difficult to maintain an accurate glide speed in our slick airplanes.  I try to maintain a glide speed by holding a precise pitch attitude in the windscreen but 1" higher or lower pitch attitude will make about a 15 knot difference, as I recall.  It is easy to be at 80kts, then with a moment of inattention, I am over 100kts.  Next, a strong tailwind at altitude may be fooling the Glide Advisor into showing you better glide range at altitude than lower down, where the tailwind can be lower.  It would be discouraging to see the glide ring shrink as you get lower.

Next is the challenge of determining your aimpoint-- where you are going to impact the runway/intended landing zone.  We are in the habit of flying the airplane to the numbers, but not only is it hard to judge aimpoint thousands of feet AGL and miles from the intended landing point, flying straight-in to the approach end of the runway leaves no room for error.  Better to approach the airport high until within about 2-3 miles, then establish an aimpoint to touchdown.  Even better to get to a "high key", crossing the landing point at 1000' AGL or so, and flying a downwind, base, final pattern to touchdown.  A circling approach gives lots of room for tightening or widening the glide as required.  I can often do this in idle without touching the power (but not always!)

To make a good engine-idle practice approach, I must estimate the landing winds correctly and remember that a high visual speed and long aimpoint on downwind may disappear with a headwind on final.  It is generally recommended to aim about 1/3rd of the way down the landing zone but this is problematical in a slick airplane that can easily arrive 1/3rd of the way down with 15-20 extra knots.  It's good to use the 1/3rd rule but don't carry it too far.  As you get closer to touchdown, you probably don't want all that runway behind you.  However, with any sort of wind in the pattern, I have to caution myself to mentally move my aimpoint into the wind--for example, to make the airplane appear to overshoot base for a right crosswind or aim, say, half-way down the runway with a strong headwind on final.  Finally, I have to be very careful to maintain a pitch attitude that will maintain a constant glide speed, and therefore I can detect where the glidepath will impact the ground.

The Cozy landing brake is not very effective until in the roundout but an aggressive slip can be useful to wipe off speed or altitude.  I am disgusted if I arrive at my touchdown point with 15-20 extra knots of airspeed.  Energy to be dissipated in the crash is the square of the velocity, they say.  Another thing they say is not to hit anything fixed.  If it was clear I was going to run off the end of the runway, I'd start the nose gear retracting.

I often think about whether to land on a highway.  Maybe, but I fear causing a multi-car wreck with inadequate liability insurance.  I might try an interstate if the traffic was light.  I would have more latitude to stretch a glide or not, to get in between traffic.   Brrrr!  Scares me to contemplate it.  I'd rather land in a nice smooth field and make whatever repairs are necessary.

Anyway, I urge canard fliers to practice power off approaches at every landing.  Analyse your mistakes.  It is no use to practice them from 9500' AGL in idle power but it's worth thinking about the problems of a long straight-in glide.

A while back, I cut the power on takeoff and practiced a return-to-the-runway.  I figure 500 AGL would be quite doable.  300' AGL would be dicey.  Try it for yourself.  It's nice to fly a stall-resistant airplane for this maneuver.

[Voidhawk9]

Good write-up Kent, I completely agree.
Pushing the glide just a bit further than it looks like you can make is a recipe for serious disappointment.

I recently flew a type I hadn't flown in a year, and so practiced some glides for my own currency. Happily I nailed them, but admittedly this particular aircraft glides a bit like a Space Shuttle, which I think actually makes it easier in some ways.

I have tried the return-to-runway 'impossible turn' in several different aircraft. It certainly varies a LOT with the characteristics of the aircraft in question, and can require some aggressive maneuvering - which is VERY risky if you are in a stall-able type and not practiced in such flying. And most people are not, and would likely fail to complete the turn safely.

I try to practice some 'emergency' or 'off-nominal' procedure on every flight, if practical, to maintain some currency in them. And a good flight simulator is a suitable place to practice some of the more hazardous maneuvers in safety, it can be educational and enlightening.

[Marc Zeitlin]

9 hours ago, Kent Ashton said:

Just reading about a guy who lost his engine at 9500 feet and landed 100 feet short of a runway doing a fair amount of damage to his Cozy...

I concur with 95% of what you wrote, but there's this, with respect to your note and Cameron's followup regarding glide, in THIS particular case.

I have not seen the posting either of you are referencing - maybe it was on FB, because it doesn't seem to be on any of the mailing lists. But I have spoken directly to the pilot in this case and it's possible that I have information that might not have been publicly posted. I was not asked to keep this private.

The engine failure occurred at 9500 ft., and the distance to the airport to which he attempted to glide was (IIRC) 17 NM Interestingly, these are exactly the numbers that _I_ experienced during my propeller loss - we were at 9500 ft., gliding to an airport at 500 ft. elevation that was 17 NM distant. We arrived at the airport 1000 ft. above pattern altitude - IOW, 2K ft. above the airport, with (obviously) more than enough energy to make the field. So when the pilot told me that he landed 100 ft. short of the threshold, I was very surprised, because there's no way he shouldn't have made it as long as the wind was not excessive (which it wasn't).

After a bit of questioning, he told me that he, too, arrived at the airport very high - approximately the same 2K ft. AGL as I had and that the issue occurred because he misjudged the unpowered APPROACH. In this case, there was no issue with glide rings, L/D ratio estimations, or anything like that (although obviously all of those are important) - the issue was completely in the pattern approach positioning - over the airport at 2K ft. AGL, we should all be able to touch down on the runway.

I was not in the plane - I don't know how that type of error was made - but I will say that although I attempt all of my landings in my plane with the power pulled to idle at mid-field, downwind and try to touch down within 500 ft. of the threshold, one of every 10 landings or so require a blip or two of power, if I've misjudged the wind or my IAS a bit. But when I do NOT have the knowledge that my engine is working, I do not rely on the ability to blip the throttle - I shoot for a landing brake down touchdown at 1000 ft. from the threshold with the LB down, and retract it if necessary to improve the glide.

In any case, THIS particular accident was caused by a misjudged unpowered approach - NOT a distance glide issue.

[Voidhawk9]

Thanks for the additional info, Marc.
I agree it is a good habit to make all approaches a glide (where practical) as practice - will certainly work strongly in your favour should the fan get quiet for real.
I've been doing this for most approaches for many years, and like Marc, I probably have 1 in 10 that requires a blip of power due to wind being a bit stronger than expected, distance slightly misjudged, or simply a  failure occurring between the panel and the seatback.