What is the limit G load plus and minus of Verieze?

[fjk]

Hey,

What is the limit G load plus and minus of :

1.  A varieze built today (if that is possible)?

2. A vintage varieze?

I ask because it seems there was serious concern about the limit load factor on VE from past CP writings and it is unclear from that whether or if

there was ever a fix or inspection/recanting of those concerns. 

I don't know if this had been beaten to death on this forum but I can't seem to find the definitive if it exists and this is a critical issue for me, so pointers to the real truth very welcome.

 

Thanks

f

 

[Kent Ashton]

If you can find and copy the plans, you can build a Vari as people are doing with the Open-ez on this site.   The Varieze POH is here   http://roynouguier.free.fr/vezoman.pdf     I do not see any G-limits but the POH suggests a maximum empty weight 580 and 1100 for takeoff.  I suppose the G-limit isn't specified because it depends on your weight and what you tested to.  I imagine a lot of Varis are heavier than Burt planned for.  I do not recall one coming apart.

AFAIK ( I never owned a Vari), the corrosion problem in the wing attach fittings was not satisfactorily resolved.  It depends on the individual airplane, the preparation of the aluminum plates, how the airplane was stored and protected from moisture and is hard to diagnose and fix.  Apparently the wing-attach plates in a new airplane are just fine but where to buy them?  I don't know.  A machinist could make them.

I believe I've read about a guy who built a Vari using the sort of centerspar and wing attachment system in the Long-ez/Cozys but I wouldn't attempt that unless I'd built a Long-ez first and understood how those were built.

I would guess a Vari that lived out west or was hangared all it's life would be OK.  I'd be "vary" suspicious of one stored outside in a marine environment.  There has been lots of discussion about Varis and the wing attach problem over the years.  Unfortunately, Google does not cover all the canard websites and list-servers very well.  Try the links here  (CanardAviation.com has died)  

 

Edited March 10, 2021 by Kent Ashton

[fjk]

Hey,

Thanks for the poh link - the one I had found was very much broken.

f

 

[Marc Zeitlin]

On 3/9/2021 at 9:32 PM, fjk said:

Hey,

What is the limit G load plus and minus of :

1.  A varieze built today (if that is possible)?

2. A vintage varieze?

I ask because it seems there was serious concern about the limit load factor on VE from past CP writings and it is unclear from that whether or if there was ever a fix or inspection/recanting of those concerns.

So the POH is very clear on the "as designed" limitations of a Varieze. The V/N diagram on page 22 shows an positive "G" limit of 5G, and a negative limit of -2G. Assuming that one built a VE today and used appropriate protection techniques for all the AL wing fittings, those would be the limitations, AT the MGW of 1050 lb. per the diagrams on page 26.

Now, given the wing attach fitting corrosion issue, RAF lowered the limits to +2.5G and -1.5G, based on nothing other than "sh*t - we don't know what to do about this, but the wing attach fittings might be substantially weaker than planned". It was intended to be a temporary change while a fix was developed, but no fix was ever developed by RAF.

There are a couple of folks that have figured out how to replace the fittings, and have done so, but it's a 40 - 80 hour job, so if you're paying someone to do it, it's a substantial portion of the cost of the airplane. And since there's no way to determine if there's corrosion without taking the fittings apart, well, it's a catch-22.

Most planes are fine, but having seen 4 sets of corroded attach fittings that were in flying airplanes, to me, VE's are somewhat problematic and whenever I perform a Condition Inspection on one, I include a very clear note about the wing attach fittings being uninspectable and a complete unknown.

[fjk]

On 3/12/2021 at 9:46 AM, Marc Zeitlin said:

So the POH is very clear on the "as designed" limitations of a Varieze. The V/N diagram on page 22 shows an positive "G" limit of 5G, and a negative limit of -2G. Assuming that one built a VE today and used appropriate protection techniques for all the AL wing fittings, those would be the limitations, AT the MGW of 1050 lb. per the diagrams on page 26.

Now, given the wing attach fitting corrosion issue, RAF lowered the limits to +2.5G and -1.5G, based on nothing other than "sh*t - we don't know what to do about this, but the wing attach fittings might be substantially weaker than planned". It was intended to be a temporary change while a fix was developed, but no fix was ever developed by RAF.

There are a couple of folks that have figured out how to replace the fittings, and have done so, but it's a 40 - 80 hour job, so if you're paying someone to do it, it's a substantial portion of the cost of the airplane. And since there's no way to determine if there's corrosion without taking the fittings apart, well, it's a catch-22.

Most planes are fine, but having seen 4 sets of corroded attach fittings that were in flying airplanes, to me, VE's are somewhat problematic and whenever I perform a Condition Inspection on one, I include a very clear note about the wing attach fittings being uninspectable and a complete unknown.

Hey - my dumb for not figuring out the poh on g limits...

This is all depressing and gratifying in that it seems like reality and there is at least a way to mill out the wing structure and take a look (presumably after purchase...) and I assume it can then be rebuilt (God knows how wrt connecting to severed strands of fiber???  I should talk to these aforementioned people.). 

I assume that the LE does not use such an Al fitting?  I should check the open EZ plans.

The entire situation with testing buried load paths in composites seems quite daunting.  I've lost friends to this issue, and due to blunders by real big factories doing carbon vac bag and autoclave (presumably).

Thanks for the info

Regards,

f

 

[Voidhawk9]

15 hours ago, fjk said:

I assume that the LE does not use such an Al fitting?  I should check the open EZ plans

 

Correct. LE, Cozy etc. simply bolt the wings to the center section with 3 bolts per side. There is Al in the hardpoints, but they are buried and protected.