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VH-SRS 170 knot Sonerai II

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TurbAero

Well-Known Member
Supporting Member
Joined
Apr 15, 2017
Messages
172
Location
Adelaide, Australia
I am starting a thread about a "Super Sonerai II" that has been developed in Australia by world record setter Robin Austin. His new Sonerai II is registered in Australia as VH-SRS. It is fitted with a stock Rotax 912ULS and has a cruise speed of around 170ktas with 2 on board.

I am reproducing some information from Robin that has posted on another forum:

SERA-173 (VH SRS) is the 3rd aircraft in my journey of developing evolutionary aircrafts originally based on the 1970 Monnett Sonerai II design.
The mission was to build the smallest most efficient 2 seat aircraft outside, with the biggest achievable cockpit inside.
SRS is likely the first Rotax 912 aircraft capable of carrying 2 large adults whilst achieving genuine RV series performance.
Although maintaining Sonerai heritage, SRS is considered sufficiently divergent from the original Sonerai design to warrant a new name, hence the SERA-173 (Stands for Sonerai -Evolution -Robin -Austin - 173 knots max cruise speed)

Broadly speaking the SERA 173 specs and differences from a standard Sonerai 2 are as follows (all solo)

  • Max continuous cruise speed 173 Kts
  • All day everyday cruise speed 165 Kts (24”/4800rpm)
  • Economy cruise - 160 Kt at 15.2 L/hr
  • Aerobatic +6G -5G
  • VNE 180Kts (testing included full range flutter testing up to and including 200Kts)
  • 300Kg empty - 600KG MTOW – 300Kg payload
  • RV10 cockpit dimensions - comfortable for 6’5” pilot, 6’2” PAX (Sonerai volume +67%)
  • Centreline flying from front seat
  • High strength crash resistant zone around pilot (2.5X FAR23 requirements)
  • Airframe structural strength = Sonerai +25%
  • Airframe efficiency = Sonerai +72%
  • Stall speed slightly less than Sonerai II (minimum solo 39Kts)
  • 1250 NM range at 160 Kts
  • 1700 NM range at 100 Kts
  • Also comfortable at 70 or 80 Kt “loitering” speed
  • Constant speed propeller with latest Sensenich high speed blades
  • 23” prop clearance for gravel strips
  • Full span (30 degrees deployment) electric flaperons
  • Horizontal Stabiliser - electric inflight adjustable
  • Rotax 912 reliability and operating costs

    Although now flying for 150 hrs over 3 years, SRS is still “work in progress” hence the temporary SERA 168 logo (which was based on the target design cruise speed). SRS also features 1-person-easy-folding wings to minimize hangar space requirements, or in this case negates the need for a hangar as its current home is a custom built, generous sized, air-conditioned enclosed trailer (See photos attached) which doubles as a hangar and workshop and lives right outside my garage (I can play with my toy anytime!).
The design, construct and refinement project (including trailer) has taken 8 (enjoyable) years and development continues.

And some additional information provided by Robin on the same forum:

Re prop... the blades are C65AY Sensenich. Hub and electric CSU, spinner etc. are Airmaster. All commercially available and **** good stuff too. Very well engineered. All integrated by Airmaster as turn key product.
To be honest, can’t tell you min ground roll as I operate off gravel strip and am quite conservative with power application. Not stol but still quite short. From memory it’s well under 200m solo, but don’t hold me to it.
I regularly take off and land on first half of 600m strip with minimal braking.
Wing section changes were intended for top end speed, but made biggest difference at bottom end. With flaperons, it only has to accelerate to 40 kts although I usually lift off at 50.
Initial stabilised climb is 1730 ft. per min as tested solo at ISA. Less if hotter or higher. This is less than SGS as this plane is unavoidably 30 Kg heavier as it is larger and stronger. This is the only area it has less performance than SGS.
Motor is bog standard 912 ULS. Except altitude leaning provisions.
No plans or kits proposed.



And some photos that Robin has provided:

1.jpeg2.jpeg3.jpeg4.jpeg
 
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