Gross Weight Increase For Sonex/Waiex

[pfhoeycfi]

As members of the EAB fraternity we can declare whatever we want, although prudence would dictate that we stay within what Sonex approves. Still it seems like the email they sent out, or a printout of their home page article would suffice to satisfy the DAR.
https://www.sonexaircraft.com/gross-wei ... se-101424/

I emailed my DAR the link to the announcement on the Sonex website and he was satisfied with that. He advised 5 hours in phase 1 in the original test area along with the appropriate logbook endorsements and updates to my manual/wb.

Peter

[Skippydiesel]

Hi Mark,

This is virtually the same aircraft that has been in production for some 13 years, with no significant changes to airframes integrity - only now, when a new US higher weight category has been established, has it been magicly discovered, that it can safely TO with an additional 32 kg.

Perhaps in another year or two, when you have "conducted new analysis and testing" you may establish a 600 kg Max TO weight limit.

Your response to a domestic change in weight limits, has been admirably prompt. The failure of Sonex to address their overseas customer needs, in this area, not quit so commendable.

I hope you can forgive my cynicism.

[flyguy0609]

WOW......I don't know what to say.

[Bryan Cotton]

WOW......I don't know what to say.

Don't say, just ignore.

[markschaible]

Don't say, just ignore.

Great advice, Bryan!

[Scott Todd]

I'll say....Its how the airplane was designed. If people are unhappy with it, pick another airplane or design your own.

The airplane could probably safely take off with another 100 pounds. Would it be safe to fly? Probably not. Would it be safe to land. Probably not. Would it be stall/spin tolerant? Probably not. Would it be appropriate for intermediate pilots? Definitely not. There are plenty of advanced airplanes out there with higher wing loading that fill a different mission. The Sonex fills its mission just fine as it is.

Sonex has always stood behind their product and offered great customer support. The airplane wasn't designed to be a heavy hauler. Its a simple airplane for two fit size people to fly locally or to the $100 hamburger.

Just pick a different one.

[Scott Todd]

FWIW, the Google says a Cessna 150 has a useful load of 478 pounds. Foreigners can convert it. A Sonex-B, at the advertised 680 pounds, HAD a useful load of 470 pounds, The increase brings it to 540 pounds.

[Kai]

Mark,

Be it far from it that I´d be the one to mar this moment of rejoice and jubilation- and very much looking forward to revised editions of Flight Manual and drawings. But- what about us?

Us, all the Sonex supporters in the Old World, who are fighting a running battle with FAA authorities considerable less broad minded than those in the US. There is not a single Sonex over here that lawfully flies without some sort of Type Accetance as an LSA from a nationally accredited flight organisation: i.e a Typenantrag from DAeC (German Aero Club), or a TADS from LAA, to mention a few that come to mind.

Slowly we are awakening to the more stringent ruling imposed by the for us fairly new 600 kg mtom limit for the LSA class. To delve a little further into the documentation that the UK based LAA has issued quite some time ago, their Technical Acceptance Data Sheet (TADS) 337 lists the Sonex with a mtom of 1150 lbs for 100HP+ aircraft.

As the general ruling is that there must be correspondence between manufacturers claims and independent type acceptance data, presently 1150lbs is still our limit.

[Skippydiesel]

It would be great IF people actually read what I wrote.

In short;

I welcomed the weight increase and commended Sonex for providing it.
A year or so ago, I sought a weight increase, from Sonex, for my Legacy.
This request was summarily rejected - from imperfect memory - safety/design limitations may have been mentioned.
A year or so later - weight increase!!!, in response to legislative changes in the USA.
No structural changes to aircraft
Analysis & testing, after 13 years, suddenly determines the aircraft could have flown at a higher TO weight all along

Just the last two points alone, might just make a person wonder -

Is there potential in this lovely little aircraft, for further TO weight increases?
Why has the aircraft not been comprehensively analysed/tested, at some time between its inception and today, for its maximum safe capacity?
If the aircraft was always capable of accomodating a higher weight, why was this not stated in the POH/Specifications? - you must still operate within your legal (weight) limits

This is a "paper" change, no structural or flight limitations. Am I the only one that thinks this is a tad convenient?
Collectively, the sequence of events suggests (to me) a parochial, overly conservative approach, by Sonex, to customer service.

[Murray Parr]

I flight tested my Waiex B with a Rotax 912 ULS 100hp up to 1213 pounds (550KG) and don't believe those little wings can safely do much better than that. In fact, I am a bit cautious the few times I have flown at this weight and definitely need to be more conscious of density altitude, runway length etc. when doing so.

I think Sonex is correct with their 1220 limit and feel you would definitely need a fair few more horses to increase that limit. Let's face it, you could get anything off the ground with enough power.

I also wonder if the landing gear would be near its limit at 1220 pounds and that could also be a good reason to not go higher weight than this. But then, you could just beef up the landing gear strength and maybe then you could further increase the weight limit if you had enough power. But then, you would have added more weight in doing so and you would then need to increase the weight limit even further to get any gain....

Sorry, I couldn't resist that last little ramble....