Sonex Weight and Balance Examples

General Community Resources
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Feel free to add your completed aircraft to the table below to help other builders with their weight and balance. Rather than adding your information in a new reply below, hover over the table and click the pencil icon on the top right part of the table to add your information.

Aircraft Type User/Tail Number Empty Weight Moment Gear Engine Finish Equipment
Sonex 19-7898 675 43330 Taildragger Jabiru 3300 Yes Prince Prop
Sonex N157SX 670 43747 Taildragger Jabiru 3300 Yes ACK 496/121.5 E-04
Sonex N50NX 634 40400.6 Taildragger AeroVee None EBC 102A ELT
Sonex N875SX 668 43841 Taildragger AeroVee None ELT
Sonex VH-MND 665 43289 Taildragger 2.4L VW Yes
Sonex N629SX 671.7 40798.8 Tri-gear AeroVee None King ACK ELT, MGL Xtreme Mini EIFS, Sandia STX 165R remote transponder, MGL V6 Com, standard Odyssey battery in engine bay, led nav/strobes . Partially painted.
Sonex SN 439 655 42129 Taildragger AeroVee None ACK E-04 ELT, magnetometer, MGL EFIS, no steam gauges, smoke system, polished, ELT, transponder, MGL radio
Sonex N1517S 685 42681.5 Taildragger Turbo AeroVee None ACK ELT
Sonex 19-8706 640 41784.9 Taildragger Jabiru 2200 Yes none
Sonex N920MB 652 42699.8 Taildragger AeroVee None ELT, Baggage Sling, Empty Weight includes smoke system components and oil separator.
Sonex N462SX 680 43828 Tri-gear AeroVee Yes Sandia Transponder, ELT
Waiex S5-MMX 652 42675 Tri-gear Jabiru 3300 None nil
Sonex nwade 676 43917 Taildragger Turbo AeroVee Yes ACK ELT, Trig TT22, MGL SP-6, sm fire extinguisher
Waiex-B 19-1614 739 47627 Taildragger Rotax 912ULS Vinyl Wrap 2 antennaes
Xenos bvolcko 800 54877 Taildragger AeroVee Yes MGL SP-6 magetometer
Sonex-B N239SX 731 46640 Tri-gear Jabiru 3300 Vinyl Wrap MGL avionics suite with autopilot servos, Trig Transponder, Sonex sourced leather seats, standard battery
Sonex-A N726CJ 654 41800 TW RevMaster Yes Prince Prop, Matco Brakes & Wheels, EarthX bat.
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It looks good, however it would be better for analysis if it had more information. Specifically, by adding a few columns for, engine (Aerovee, Jab220, Jab330,…) , Landing Gear Configuration, ( Conventional or Nose) Weight on Main gear, weight on Tail/Nose gear, and Finish (paint or polish).

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The old Google doc copy is available too.

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Thanks, Bryan!

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Thanks Brian, This format will enable us to generate some useful insights. The more data we have, the better the insights we can gain. I use this when evaluating build options and mods.

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My buddy and I were talking SHX weight and balance, and I made up this draft spreadsheet. Mark had talked about the CG being a bit aft with the really light UL Power engine. I did chuck a cell in there with an engine spacer, but from the numbers that does not seem to buy you much. I also chucked in 215 lbs for a Corvair and that looks a lot better as compared to the 173 lb UL Power. Feedback is welcome. Note that I used the UL Power web data for the engine CG, and assumed 5” for both prop thickness and spinner length. I’ll have to measure them later, at least the ones I have.

I noticed that the serial number is SHX0001 and I thought SHX would be a good abbreviation for the high wing.

Highwing W&B.xls (13.5 KB)

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Does the Nose wheel configuration move the CG forward? If so that might be a good combo with the HW current CG (EarthX etc)

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I think it has to, but probably not a ton.

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Hi Bryan C - for your spread sheet

Sonex Legacy, Rotax 912ULS, Airmaster / Whirlwind 3 blade CS prop, Tail wheel.

Hobbs; 178hrs

Plans Built. Solid rivets throughout.

Max Take-off Weight; 554 kg

Empty Weight; 340 kg

Useful load; 214 kg

Load after full fuel; 145 kg

Max baggage; 18 kg

Fuel Capacity: 30L X 2 wing + 40L fuselage header = Max fill 96L

Pannel; Dynon Classic Skyview EFB, Trig Transceiver & Transponder. iPad mini with OzRunways, Guardian mini iPad docking/charge station & duel USB-A charging port (would not purchase from Guardian again).

Back up instruments; SkySport Compass & Chengfeng Instruments Air Speed. Garmin GPSMAP 96C & PLB GME MT610G

Undercarriage; Tracey O’Brien Hydraulic toe brakes, 5” rims and Aviation Products Inc full swivel 4” tail wheel (considering going to 6”). Tyres; Goodyear Flight Custom III 5.00 – 5 6ply.

Customisation; Home designed/made cowling. Rotax Large Coolant Radiator mounted below spinner, Rotax Extra Large Oil Cooler bottom of firewall, in cowling exit airflow - seems to work OK. Carb ice prevention by Cozycarb. Carb inlet air via home designed/built air box delivering ambient air from front of cowling.

This is the only Sonex I have flown, so cant realy make informed comparison comments; She seems a little tail heavy/nose light ie some tail down elevator must be carried, if only me (70kg) on board. Put stuff in the baggage compartment and or a passenger, changes this significantly.

She has a top air speed of 147 knots Indicated @ 5,500ft and I cruise at 130 knots True /25”MAP, 5,000 RPM, Average fuel burn 14.25L/hr. Plan @ 15L/hr(single pilot).

Handling; Some right rudder is required for TO/Climb. In Cruise she flies straight & level (Ball Centered) no rudder input required for gentle turns. Stick an adult passenger in the right seat and some left stick is needed and an unexpected amount of left rudder, to centre the Ball (working on a KISS modification to correct this).

Other;

I would suggest she is both useful load and space (volume) limited. Her performance more than makes up for her limitations.

The 4” Tail Wheel limits ground operations to nice firm (dry) grass or paved taxi/ runways.

An electrically operated Cowl Flap has been made, fitted & tested - no discernible benefit at this time. Removed pending a rethink.

Grass/dirt runways - Undercarriage oscillation is significant, This has lead to wheel fairing & fairing mounting plate damage. Repairs with added support have had to be made. Considering leaving wheel pants off, when operating on other than paved runways. :smiling_face_with_horns: