SonexBuilders.net

The 31.75 kg (70 lb) increase in Max TO weight, to 553.33 kg (1220 lb), for aircraft powered by 100 hp or more, is indeed welcome BUT DOES NOT GO FAR ENOUGH !

Sonex need to realise that they are not just supplying aircraft and responding to legislative changes in the USA , they have a following all over the World, that would like to be considered.

Recreational Aircraft Australia (RAA) TO weight limit for its aircraft, has been 600 kg (1322.7lb) for very many years. I believe much of Europe is there now.

The 600 kg is subject to manufactures'/builders discretion however most have moved to this.

600 kg facilitates "away" trips, by allowing for additional fuel/duration and make the ability to carry PIC & a lightweight adult + a toothbrush, much more feasible.

I am not an aircraft engineer however it seems to me that an aircraft designed for aerobatics at 431 kg (950 lb) +6 / -3 Gs, is plenty strong enough to operate in the Utility Category at 600 kg.

Come on Sonex, get with it!

1220 lbs. is the absolute limit of what we can and will approve for the Sonex and Waiex structurally in Utility Category.

I understand the notion to always want more, but there are more dynamics at play here than structurally supporting the weight. I welcome the additional 70 pounds. I'm sure at some point that will come in handy.

In regards to the increase - will sonex issue a drawing revision for the cover page or some other similar paperwork I can present to my DAR since my plans say 1150?

WaiexB22 wrote:I understand the notion to always want more, but there are more dynamics at play here than structurally supporting the weight. I welcome the additional 70 pounds. I'm sure at some point that will come in handy.

In regards to the increase - will sonex issue a drawing revision for the cover page or some other similar paperwork I can present to my DAR since my plans say 1150?

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/

In regards to the increase - will sonex issue a drawing revision for the cover page or some other similar paperwork I can present to my DAR since my plans say 1150?

We will have drawing revisions with downloadable PDF copies available for the B01 drawing of A-Model and B-Model Sonex and Waiex plans. There will also be Flight Manual revisions forthcoming as-well, and we'll make the specific revised pages available as a PDF download.

Hi all,
Thanks mark for you and all your staff for the effort to make this upgrade. Yep easy to download , present to fsdo and phase 1 5 hours new flight test and data. record on logbook.
Hope things going well at Sonex Llc.


WaiexN143NM
Michael
retired FAA
SBPF board member
EAA Lifetime

Hi Mark,

markschaible wrote:1220 lbs. is the absolute limit of what we can and will approve for the Sonex and Waiex structurally in Utility Category.

You pretty much said the same thing when, about 12 months ago, I requested a "one off" Max TO weight increase for my Legacy. This was on the basis it has wing tanks - often seen, by aircraft designers/manufacturers', as allowing a weight increase.

Suddenly, in response to legislative change, (no structural/design change) a very welcome weight increase is possible.

You pretty much said the same thing when, about 12 months ago, I requested a "one off" Max TO weight increase for my Legacy. This was on the basis it has wing tanks - often seen, by aircraft designers/manufacturers', as allowing a weight increase.

I think that conversation was closer to 3 years ago! Wing tanks are not a panacea and do not automatically increase limit load. They can actually have the opposite effect when it comes to gust loading. We are not in the business of granting "one off" dispensations to vary from our published specifications, which are the result of analysis and testing. We have conducted new analysis and testing and 1220 lbs. is the limit we have established.

When I did phase one flight testing on my Sonex TD with a Jabiru 3300 I found it met the Light Sport Pilot stall speed requirements at about 1,250 lbs max, and have considered it safe to fly in the "normal" category above the 1,150 pound limit but have avoided listing that on my official paperwork which sometimes made it difficult to find a DAR or CFI who would fit. The extra 70 pounds will definitely help with that and I am updating my paperwork today.

10 years ago I dumped my problematic hydraulic lifter Jabiru with its very questionable 120 HP rating, and installed a solid lifter CAMit 3300 that was dyno tested at 127 HP and then last year installed new forged pistons in that which gave at least a 10% power boost based on static RPM, I estimate it is now about 140 HP and once the new sport pilot regulations are official I plane to install a steeper pitched prop for higher cruise speed as well. (Solo with half fuel on a cool day I have seen climb rate near 2,000 FPM.)

David A.

DCASonex wrote: (Solo with half fuel on a cool day I have seen climb rate near 2,000 FPM.)
David A.

I'm jealous. But since my last round of modifications I'm seeing a solid 1000 FPM with those parameters, which seems pretty good for the AeroVee.