What wound up happening to the CH601XL?

[SkyHog]

Last I heard, the FAA was considering (or maybe the decided to) ground the entire fleet of 601XLs. Anyone know what wound up happening?

 

[N801BH]

Yup.... After years of the Zenith company claiming there was NOT a problem, numerous crashes with the wings far from the rest of the debris piles ,the FAA and most other aviation reg groups around the world pretty much said to Zenith... Fix the flutter issues or ground the fleet...

Zenith came out with a mod, now called the 601XL-B.....

Since then .. Not ONE crash associated with shedding wings.

Of course Zenith is still saying there was NO problem in the first place.....

Draw your own conclusions..

 

[X3 Skier]

IIRC, they also beefed up the wing spar as well. AFAIK, Zenith replaced the 601 series kits with the 650, at least in the USA.

Lots of who did what and some feel a basic design flaw aggravated by near or over the limit operation, others believe it was a design flaw well within the envelope.

Still since the mods, no more problems noted as Ben says.

Cheers

 

[KeithASanford]

The original wing was put through a series of rigorous flutter tests and the result of the modification, I would bet, is probably one of the most strictly engineered wing structures in the experimental aircraft.

 

[N801BH]

....., I would bet, is probably one of the most strictly engineered wing structures in the experimental aircraft.

Yup... It is now..

Too bad a dozen or so fellow pilots paid the untimate price to get here...

 

[tinerj]

I'm reworking the 601XL to 601XLB. The changes are numerous, but only adds 35 pounds to the plane.
The wing root is beefed up,
the place where the ailerons horns attach are made of heavier aluminum and braced across two ribs,
the wing skins have a row of angles added along the center-line their entire length on both top and bottom,
a much heavier extruded angle of aluminum replaces a portion of the lighter angle where the leading edge and top wing skin attaches to the wing spar,
the number of rivets holding the leading and top skins to the wing spare is doubled,
the ailerons have balance arms added,
the trailing edge has a stronger doubler,
the trailing edge opening for the aileron rods is reinforced
the trailing edge wing inboard attachment is made of heavier aluminum,
the attach point for the trailing on the fuselage is made of thicker aluminum
because of the changes to the wing root, the center wing spar is also modified, made thicker (so the wings will slide in) and strengthened,
the bracing of the center wing spar to the fuselage is increased both on the inside of the fuselage and outside.

Essentially what they did was take every possible claim as to the reason for the distressing habit of the wings falling off and address them with a modification.

I flew the company plane and the controls are very sensitive. You merely have to think that you want to make a turn and the plane makes the turn. In addition, the controls grow progressive lighter as you increase the control.

 

[SkyHog]

I'm reworking the 601XL to 601XLB. The changes are numerous, but only adds 35 pounds to the plane.
The wing root is beafed up,
the place where the ailerons horns attach are made of heavier aluminum and braced across two ribs,
the wing skins have a row of angles added along the center-line their entire length on both top and bottom,
a much heavier extruded angle of aluminum replaces a portion of the lighter angle where the leading edge and top wing skin attaches to the wing spar.
the number of rivets holding the leading and top skins to the wing spare is doubled,
the ailerons have balance arms added,
the trailing edge wing attachment is made of heavier aluminum,
because of the changes to the wing root, the center wing spar is also modified, made thicker (so the wings will slide in) and strengthened,
the bracing of the center wing spar to the fuselage is increased both on the inside of the fuselage and outside.

Essentially what they did was take every possible claim as to the reason for the distressing habit of the wings falling off and address them with a modification.

I flew the company plane and the controls are very sensitive. You merely have to think that you want to make a turn and the plane makes the turn. In addition, the pressure on the controls grow progressive lighter as you increase the control.

Did Zenith pay for the changes, or are you, as the builder, on the hook?

 

[tinerj]

In my case, I've had great support from the people at Zenith. They answer the phone, respond to emails, and give so much support, I did not begrudge the $345 (I think it was) for the upgrade kit. That is but a portion of what all the materials in the kit would cost if it weren't a part of the upgrade.

They provide four levels of kits -- scratch built (plans only), regular kit, quick-build kit, and RTF (but not from the Mexico plant.) In my case I bought the regular kit a section at a time -- rudder, tail, fuseledge, wings, fuel system, landing gear, etc. I could buy a section at a time when I was ready for it, and that spread the cost over three years.

 

[SkyHog]

In my case, I've had great support from the people at Zenith. They answer the phone, respond to emails, and give so much support, I did not begrudge the $345 (I think it was) for the upgrade kit.

They provide four levels of kits -- scratch built (plans only), regular kit, quick-build kit, and RTF (but not from the Mexico plant.) In my case I bought the regular kit a section at a time -- rudder, tail, fuseledge, wings, fuel system, landing gear, etc. I could buy the regular kit a section at a time when I was ready for it, and that spread the cost over three years.

Ahh, $345 ain't bad. I was thinking you were talking at least a grand with all those changes. I wouldn't balk at that either.

Although, I do have pretty strong opinions against manufacturers not being on the hook for their own mistakes.

 

[N801BH]

If a builder of the 601XL series were lucky enough to not have the plane built to the point of having to tear previous work out to add the "kit".. Then it is just additional building time...... I really felt bad for the ones who had finished and flying planes and had to rip them apart... Especially the guys who had nice paint jobs completed... Keep in mind, this back and forth between the company and builders went on for a couple of years too, so some planes that might have been modded were finished all because ZAC pushed back on the obvious "issues..... I guess it is just human nature to go into denial on a product you sell to refuse to believe it might have problems..

Ps... I want to say right up front..... During my build of my 801 ,the Zenith guys/gals were absolutely TOP NOTCH and I got great factory support...