VH-SRS 170 knot Sonerai II

[dcarr]

That air conditioned, well lighted, custom hangar/workshop trailer is most interesting. It probably preserves from corrosion better than most hangars!
What is the inside and overall outside width?

Agreed the trailer looks great!

 

[Robin Austin]

I like this remake of the Sonerai. It deals with some of the issues the design had inherent, without performance penalty, and adapts another power alternative.
Looks like a good combination you have come up with. Do you have drawings or instructions avialable that if someone where to build they could use as a guide?

Thanks Bill for the kind comments. Appreciated.
Although every single component has received detailed engineering design and verification, and I have sketch/drawn everything before fabrication along the way, none of thIs is in a integrated or formalised format that would be of much use to a third person.
Also, all my spare (limited) energy and time (and motivation) goes into continual development. The project is effectively never finished while I can still see further improvements.
I’m probably a better Engineer and builder than documenter.
So, sorry but I have no plans to commence what would be a hugely tedious job for me.

 

[Robin Austin]

=65-312 km/h !!!

Hi Henry.
Thanks for sharing that video. Very futuristic and exciting for sure!
Just a couple of things. The claimed performance vs fuel economy sound fantastic. Problem is, they fall way outside what even Rotax can manage. Is any of this third party verified? Perhaps they can challenge the current FAI world record for fuel efficiency. According to their numbers, this would be a cinch. And it would surely drive sales.
Sorry if I sound cynical, but I have read these sort of claims so many times, I’m over it.
Also, with a standard pilot and fuel, the passenger can only weigh 25Kg.
Or with 2 standard size occupants, you can have a total of minus 5 litres of fuel. Both these options seem a little impractical in the real world.
Please feel free to correct me if I’ve miscalculated. I will apologise humbly.
Don’t get me wrong, I as much as anyone get excited about new technology and developments. I hope someone can put me straight and convince me that these claims are fact AND as 2 seater, it is legal to actually take off.

 

[Robin Austin]

That air conditioned, well lighted, custom hangar/workshop trailer is most interesting. It probably preserves from corrosion better than most hangars!
What is the inside and overall outside trailer width?

The airfield I mostly fly from is coastal and thus has corrosion issues. I keep the trailer at home, about 15 or so kms inland, so the location helps corrosion wise.
The width is 2.499 outside (legal max is 2.500 in Australia)
Inside is 8’ exactly. Sorry about the mixed units. Not sure where you’re from so had an each way bet ha ha.
Regards
Robin

 

[Robin Austin]

Hi Henry.
Thanks for sharing that video. Very futuristic and exciting for sure!
Just a couple of things. The claimed performance vs fuel economy sound fantastic. Problem is, they fall way outside what even Rotax can manage. Is any of this third party verified? Perhaps they can challenge the current FAI world record for fuel efficiency. According to their numbers, this would be a cinch. And it would surely drive sales.
Sorry if I sound cynical, but I have read these sort of claims so many times, I’m over it.
Also, with a standard pilot and fuel, the passenger can only weigh 25Kg.
Or with 2 standard size occupants, you can have a total of minus 5 litres of fuel. Both these options seem a little impractical in the real world.
Please feel free to correct me if I’ve miscalculated. I will apologise humbly.
Don’t get me wrong, I as much as anyone get excited about new technology and developments. I hope someone can put me straight and convince me that these claims are fact AND as 2 seater, it is legal to actually take off.

Sorry folks if I sound grumpy today. I usually keep my mind to myself unless it’s positive.
But I get more than a little disappointed when aircrafts are marketed to often non-technical pilots who can’t weed through the marketing claims and who often don’t have the experience to conclude the impracticality of and often illegality of flying 2 seat aircrafts that can’t comply with legal requirements especially with European rules, or don’t understand the true performance vs economy until after they are the proud owner.
ok, I obviously need some sleep, so I’m off to bed!

 

[Robin Austin]

Sorry folks if I sound grumpy today. I usually keep my mind to myself unless it’s positive.
But I get more than a little disappointed when aircrafts are marketed to often non-technical pilots who can’t weed through the marketing claims and who often don’t have the experience to conclude the impracticality of and often illegality of flying 2 seat aircrafts that can’t comply with legal requirements especially with European rules, or don’t understand the true performance vs economy until after they are the proud owner.
ok, I obviously need some sleep, so I’m off to bed!

It appears there are 2 different specs for the aircraft. I’ve just found an alternate website that shows a 600kg MTOW rather than the 472Kg in the video and other marketing.
This is a good thing, but my comments above still apply re performance/economy and to usage of this aircraft in Europe and any countries that have similar weight restrictions.
Don’t get me wrong. I can see this is an exceptional aircraft in many ways and may well forge a path to the future. And I Sincerely congratulate them for all their work and results. I know how much work they have done! It’s just that the specs / performance claims / data / video presentations all fail to tie together. Any single claim I can accept, but when the various claims contradict or are collectively implausible, credibility goes out the window. Detail does matter.
I’ll probably cop a hiding here for something I’ve totally misunderstood, but my comments here are in good faith with my current understanding of various world regs. Please feel free to enlighten me in a constructive manner.
Thx.

 

[TurbAero]

... The claimed performance vs fuel economy sound fantastic. Problem is, they fall way outside what even Rotax can manage. Is any of this third party verified? Perhaps they can challenge the current FAI world record for fuel efficiency. According to their numbers, this would be a cinch...

Risen also claims “speeds unheard of in any aircraft powered by the Rotax 912 engine.”

Erm, Robin‘s documented world speed records exceed the maximum straight and level speed of the Risen and VH-SRS can also do better than the Risen.

Perhaps the Risen team haven’t done their homework when making their claim...

Robin, what you have achieved is outstanding. Congratulations!

Dave

 

[Vigilant1]

Thanks, TurbAero, for starting this thread. Robin, that's quite a plane--beautiful work and great numbers.
As I'm sure you know, Sonex (and John Monnett) have taken the Sonerai design back under their wing. John has a reputation for ardently opposing significant changes to his designs, but with that said it might be worth approaching Sonex with your developments. I >entirely< understand why you don't want to get into the promotion, production, sales biz, but arranging for your work to be transferred to Sonex assures your work lives on and broadly benefits others (and gives Sonex a new product to sell). Anyway, a thought.

I'd need the fantastic trailer...as a doghouse to move into when my understanding bride finally loses her patience.

Mark

 

[BBerson]

Robin has been through a validated world speed record setting process with his other Sonerai. He knows how to accurately determine his true air speed. As he says, his target is 173ktas but he is only achieving 168ktas with this variant (with tweaking to go). I do not know whether his current speeds have been validated officially, but I have confidence that if he claims these speeds, they are legitimate.

While he hasn’t yet achieved his target of 173ktas, he has hit his target of an RV performance on a Rotax 912, and with the ability to carry 2 large sized people. This was never about achieving another world record, only to achieve some personal targets. He is very close to doing that and even if he doesn’t ultimately make it, he has achieved a creditable outcome for his project.

Are the official speed runs flown near sea level and then corrected for temperature etc.?

 

[sming]

Please feel free to enlighten me in a constructive manner.

I'll try!
You have to understand the european ultralight context. The 450kg MTOW probably comes from France in the 70's, to regulate the "flying lawn chair" of the era. The regulators for once were quite intelligent, they decided that with a MTOW of 450Kg AND a minimum flying speed of 65Km/h (and a max power of 100HP for 2 seaters), the kinetic energy liberated in a crash wouldn't do too much damage to the ground and therefore, if you comply with these limitations, you can do whatever you want. It was followed by others countries (italy? spain? germany?) but it's always a national set of rules.
Then comes the EU, and the now "Light Sport Aircraft", which is different from the US LSA (no speed limit, retracts...), and is 600Kg MTOW, but it is certified.
With the price drop of carbon fiber, manufacturers realized they could build some pretty good 2 seaters, but, apparently, with industrial process and the nice leather seats, it's quite hard to keep the weight of these 200K€ airplanes under 300Kg, hence the "it's a 2 seater with 475Kg MTOW you can fly without a PPL, but you know, we also sell the 600Kg LSA version, in case you want to takeoff with 2 people and full fuel *wink* *wink* *nudge* *nudge*"
All the carbon fiber high-end LSA (vl3, wt9 dynamic, blackshape, tarrangon...) sell a 450Kg/600Kg version of the same airplane.
Soooo, what's happening now, is some countries that like certified and are good with composite (germany) want to push the ultralight limits to 600Kg MTOW but with more regulations, and then you have France, were we like our ULM freedom the way it is thank you very much that doesn't want it. We got an increase to 500Kg (yay!) to accommodate "modern" people and stop the hypocrisy but we refused some EU regulation and kept our national soverignty on the subject.
If you followed my rambling, what I'm trying to say is, when Risen say they are the fastest 912 airplane in the world, they mean "we are the fastest (side-by-side) 912 airplane (with a 65Km/h stall speed) in the world (of Europe)" because the european market is complicated and no sane american will fly a sub 300Kg not powered by lycoming fast aircraft. We needed you crazy guys down under to do it!

What's your stall speed?

 

[Robin Austin]

Risen also claims “speeds unheard of in any aircraft powered by the Rotax 912 engine.”

Erm, Robin‘s documented world speed records exceed the maximum straight and level speed of the Risen and VH-SRS can also do better than the Risen.

Perhaps the Risen team haven’t done their homework when making their claim...

Robin, what you have achieved is outstanding. Congratulations!

Dave

Hi Dave
Thx for the kind words, but I need to clarify the type of World Records I attained.
There were 2 aircraft Efficiency World Records, but that’s another story.
The speed records were for 1 way flights, ie point to point. This means wind assisted. All the FAI point to point distance speed records are on this basis, so yes, you need a fast aircraft, but also logistics, including a pre approved route.
The best FAI verified result I attained was 500 kms in 68 minutes, thus recording an average speed of 238 knots. This was the highest speed recorded for the weight class (up to 500 Kg) on any FAI sanctioned distance flight to date.
The actual average was 244 knots as the distance flown due to weather was a little farther, but that is irrelevant to this type of record.
I didn’t actually challenge any 2 way average speed records as these are pretty sewn up by purpose built single seat lycoming powered racing planes.
Having said that, yes, the SERA is faster than the Risen claims to be but only by 2.7% to 9% (depending on which figures I compare) however, Risen have taken that extra (huge) step in moving to a production aircraft. There are of course other pros and cons, eg they have lower stall speed but are perhaps not aerobatic? Also side by side vs tandem, price etc.
I have to be honest, I’d never heard of the Risen until yesterday, and my initial comments were based on the linked video and website, and based on those, they appeared to be just more muddled, inconsistent claims, however after researching further, it appears this aircraft may be a standout above the rest performance wise. It’s a pity they just don’t get all their facts and figures consistent and disclose that they are effectively selling a single seater in the European class they are promoting it for.
One last comment, this is the first time EVER I have critiqued an aircraft online, and if I had my time over again, I probably wouldn’t. If I had no records, no problems, my comments would be seen as constructively critical. But, having records, they will likely be seen as sour grapes by some. I could delete my comments but since they are there, and they will likely trigger further discussion that may be beneficial to some, I’ll leave them this time..
Despite having built a fast aircraft, I am definitely a mere mortal and subject to (many) mistakes And an occasional stupid comment!
Hope that makes sense.
Oh, and if I can afford a Risen in the future, I’ll sure give one a go!

 

[Robin Austin]

Thanks, TurbAero, for starting this thread. Robin, that's quite a plane--beautiful work and great numbers.
As I'm sure you know, Sonex (and John Monnett) have taken the Sonerai design back under their wing. John has a reputation for ardently opposing significant changes to his designs, but with that said it might be worth approaching Sonex with your developments. I >entirely< understand why you don't want to get into the promotion, production, sales biz, but arranging for your work to be transferred to Sonex assures your work lives on and broadly benefits others (and gives Sonex a new product to sell). Anyway, a thought.

I'd need the fantastic trailer...as a doghouse to move into when my understanding bride finally loses her patience.

Mark

Hi Mark.
Firstly, thank you for your kind comments. Really appreciated.
I did speak with John at Oshkosh in 2011 about transferring my testing and ideas on to one of his designs in return for a discounted kit for me to apply them to on the other side of the world, but he wasn’t interested and I understand and respect that decision.
Regards
Robin

 

[Robin Austin]

Are the official speed runs flown near sea level and then corrected for temperature etc.?

Hi.
FAI have different types of speed records. All records can be flown at your chosen altitude as I recall.
The chosen altitude will usually depend on the type of aircraft (turbo or not) and the type of record chosen.
I have provided more details in a post earlier today that hopefully might clarify this further.
Cheers
Robin

 

[Vigilant1]

Hi Mark.
Firstly, thank you for your kind comments. Really appreciated.
I did speak with John at Oshkosh in 2011 about transferring my testing and ideas on to one of his designs in return for a discounted kit for me to apply them to on the other side of the world, but he wasn’t interested and I understand and respect that decision.
Regards
Robin

Thanks for giving it a try. Sorry it didn't come to pass as it would have been good for the sport.

 

[Robin Austin]

I'll try!
You have to understand the european ultralight context. The 450kg MTOW probably comes from France in the 70's, to regulate the "flying lawn chair" of the era. The regulators for once were quite intelligent, they decided that with a MTOW of 450Kg AND a minimum flying speed of 65Km/h (and a max power of 100HP for 2 seaters), the kinetic energy liberated in a crash wouldn't do too much damage to the ground and therefore, if you comply with these limitations, you can do whatever you want. It was followed by others countries (italy? spain? germany?) but it's always a national set of rules.
Then comes the EU, and the now "Light Sport Aircraft", which is different from the US LSA (no speed limit, retracts...), and is 600Kg MTOW, but it is certified.
With the price drop of carbon fiber, manufacturers realized they could build some pretty good 2 seaters, but, apparently, with industrial process and the nice leather seats, it's quite hard to keep the weight of these 200K€ airplanes under 300Kg, hence the "it's a 2 seater with 475Kg MTOW you can fly without a PPL, but you know, we also sell the 600Kg LSA version, in case you want to takeoff with 2 people and full fuel *wink* *wink* *nudge* *nudge*"
All the carbon fiber high-end LSA (vl3, wt9 dynamic, blackshape, tarrangon...) sell a 450Kg/600Kg version of the same airplane.
Soooo, what's happening now, is some countries that like certified and are good with composite (germany) want to push the ultralight limits to 600Kg MTOW but with more regulations, and then you have France, were we like our ULM freedom the way it is thank you very much that doesn't want it. We got an increase to 500Kg (yay!) to accommodate "modern" people and stop the hypocrisy but we refused some EU regulation and kept our national soverignty on the subject.
If you followed my rambling, what I'm trying to say is, when Risen say they are the fastest 912 airplane in the world, they mean "we are the fastest (side-by-side) 912 airplane (with a 65Km/h stall speed) in the world (of Europe)" because the european market is complicated and no sane american will fly a sub 300Kg not powered by lycoming fast aircraft. We needed you crazy guys down under to do it!

What's your stall speed?

Hi
Thank you for the detailed and clear description. That fills in the gaps and makes perfect sense of why the ambiguous claims and marketing. Really appreciated.
It appears Risen have done a fantastic job and put a huge effort into this project and it sure looks exciting.
I didn’t set out to make comparisons between my plane and the best state of art production aircraft in the world but it is morphing into that, so I need to pull back. Mine is clearly a simple home built, albeit with high performance, and is void of the complication of computer aided design, exotic composites and those beautifulL extendable flaps etc.
I have expanded and clarified my comments further in an earlier post today.
And yes, physics is physics. Despite my SERA having virtues such as speed, comfort, payload and aerobatics, there are trade offs, in SERA’s case, stall speed. I have quoted the minimum stall speed which is 39 knots. The maximum weight stall speed is more in line with RV stall speeds. There is a reason I won’t publish it, although you can do your own calculations. The wing is not a NACA 64A212, although it is similar in section and area. There are many Sonerai flying here and elsewhere in the world with “registered” stall speeds that are base on Monnett data, but are not realised in actual tests, and would likely not be technically legal when flown at the registers MTOWs.
So, I don’t want to open a can of worms. SERA stall speed is perfectly legal and practical at gross weights when flown in the Experimental category, but needs a reduced MTOW to legally and morally comply with many of the Ultralight type categories across the world, where as you correctly stated, the formulators knew what they were doing in relation to minimising kinetic energy.
As I said, physics is physics and no amount of hoping will change that. I just set out to achieve the best balance of attributes for my kind of flying, and although the stall is faster than many lower performance aircrafts, it is lower than most or all comparable higher performance aircrafts.
Cheers
Robin

 

[TurbAero]

Thanks for your clarifications Robin.

In my opinion, it’s not really fair to compare one persons personal project with a multi million dollar, large team development program. The SERA meets Robins personal targets and that is the most important and only issue really.

I started this thread to highlight the innovation and achievements of one of many individuals within our experimental aircraft fraternity and what Robin has done with the Sonerai I felt was worthy of mention.

Dave

 

[sming]

No worries, we're not fooled easily, and salute the efforts that went into this project. It's a dream plane !
My only regret is... where is the turbine version??
(Where is your lightning bug?? I was drooling all over your thread )

 

[Glen Maxwell]

I'd need the fantastic trailer...as a doghouse to move into when my understanding bride finally loses her patience.

I fully understand this statement, I went off with a couple of friends to look at a K8 Glider. During the inspection I climbed in and was checking the fit when the owners wife came out of the house, noticed me in the glider and ask what I thought. I looked at her and responded " when I left home my wife said to me " If you bring home another airplane it had better be comfortable enough to sleep in" " She howled with laughter and returned to the house.

 

[Robin Austin]

Thx Dave.
Except for my jibe, I think it’s all been positive and fleshed out a bit of useful discussion. Also a few ideas and thoughts that similar minded speed or efficiency nuts might find mildly educational or at least enjoy reading.
Even Mark might be inspired to build that better doghouse .
And despite a comment here or somewhere else about being protective of my records, quite the contrary. I’d actually love to see more action in this area. If the Risen can do their stated 200KPH level flight on 6 lph it would secure the FAI C1(a) world efficiency record. Rough calc, after taking into account disproportionate internal friction etc at such low loads, that’s 200 KPH on roughly 20 HP. That would be a real accomplishment.

 

[Robin Austin]

Ah, Dave.... Lightning Bug.....
Penny dropped, I just realised who I am taking to.
Is there a thread that I can get an update on your projects Dave?
If not, now that you’ve got our interest, perhaps you can give us like minded nuts an update here?
Or start a seperate thread with an update!