Sonex gross weight advisory

[fastj22]

Sonex has posted on the yahoo boards a warning that heavily built planes that exceed the 1150 lbs factory recommended gross weight could push the plane out of LSA compliance.
I just did the weight and balance on my Jab3300 and it came in empty at 650lbs. So that leaves me 500 lbs useful load. Not complaining, but im glad I have every ounce of UL.

I'm pretty sure that any other non sonex supported engine would not come in that light, so in order to stay within the 1150 limit, you either reduce useful load or increase gross and risk losing LSA. And the limits are even tighter on the Onex.

[rizzz]

I must disagree here I think.

When you say "non sonex supported engine", are you including engines like the Rotax?
The 100hp Rotax 912ULS weighs 124lbs, and the 120hp Rotax 914Ul weighs 141lbs, surely you should be able to stay within the 1150 limit with one of these?

And what about any of the other VW options besides the AeroVee, they all pretty much weigh the same? Or are you including them in the "sonex supported engine" category?

With an engine like the 0-200, the Viking or the Corvair you'll probably struggle to remain within these limits I agree.

[lucio]

Hi to everybody
I just joned the group and I am willing to make a Sonex from scratch. I wonder what the real stall speed is as here in Europe we are getting more and more concerned about this. Of course a real speed at full load say 1000 lb, if any of you ever checked it. Empty weight here in Italy is 270 kg plus 10 kg for the parachute (616 lb)

Thanks
Lucio

[rbarber]

The performance numbers posted from Sonex LLC. are accurate. Also, I have flown mine at 1250 lb (567 kg). It flys fine, as fly with appropriate care for a heavy aircraft.

R.

[daleandee]

As the owner of a Corvair powered Light Sport Sonex air frame I guess I should get into the conversation here. First, I'm not a genius nor did I sleep at a Holiday Inn Express but I'll say this ... from every calculation that I can find and of all the information Sonex has posted on their site the conclusion I have come to it that the Sonex IS light sport legal up to 1250 lbs.

I won't go through all the numbers but the clean stall reported at full gross of 1150 (46 CAS) should be 49 CAS with all things being equal. The limit is 51.8 CAS at sea level. Flight testing should confirm this but I have not yet done the gross weight testing.

There is NO wing loading requirement for LSA aircraft but IF there were there are already some that are near or more heavily loaded than a Sonex at 1250 gross.

The G rating requirement for an ASTM SLSA Sport Aircraft is 4.0+ /2.0-. When you run the numbers the 1250 gross Sonex is still inside of those numbers. Then understand that being experimental makes a difference here also. Sonex gives the Limit Load factor at +9/-4.5. Several places on their site they reiterate that all of their air frames are "engineered per FAR Part 23 by one of the best teams in the industry." Run the numbers for G loading at 950 aerobatic at 6+/3- against the 1250 gross weight and you will still see more than ample safety factor ... much more than a 3.8+/1.8- certified airplane and slightly more than 4.0+/2.0- required for ASTM built sport planes.

Weight and balance are not issues with the PC680 mounted in the tail. Full fuel and a 180 lbs pilot (No baggage) is forward CG and there is no loading configuration that pushes the CG out of the rear.

Climb performance with a 1250 gross Sonex with 120 HP beats the daylights out of a 1100 lbs 80 HP Sonex hands down so the rate of climb is not an issue. Check the numbers and see.

Many have flown at 1250 gross. I even seen a Sonex (pilot to remain nameless) that had an empty weight of 840 lbs (don't tell Jeremy - LOL!). When I asked what his gross was set at the owner replied, "I don't remember." I would never fly a Sonex that heavy.

But from all I can ascertain the 1250 lbs gross is the limit for the Sonex air frame for many reasons. That is where all the numbers seem to conclude and still remain a light sport legal aircraft.

Just one man's opinion,

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
19:42 hours - Phase One
Status - Painting complete
https://s3.amazonaws.com/expercraft/dal ... 631da3.jpg