Sonex B models

[vigilant104]

Observations:
-- The extra fuel will be handy/needed for the thirstier engines now being supported.
-- The new fuselage planform is considerably "blunter" at the front end, I'd expect at least some increase in drag vs the original fuselage. Sonex says the performance is "the same" as the original Sonex, and in the FAQs they relate that the B-model prototype airframes are "in progress", so it's not clear if they've flown yet and if the performance numbers match the old ones. I know at cruise my Sonex performance is quite sensitive to changes in drag: if I get lazy and don't keep the "bean" centered, it can easily cost over 5 knots.

Maybe someday a folding wing option? Please? Hangar space isn't getting any cheaper or more available.

Jetsam:
1) With the "Y" stick and accepting these larger engines, will the irreverant wags call it a "Zodi-ex?" A "Soniac?"
2) Now that an official, recognized Sonex can have a water-cooled engine, with a gearbox-driven prop, can the much-closer-to-traditional-acft-engine" Corvair guys start calling their planes a "Sonex" without fear of rebuke? Their "Sonex A" models with 17 gallons aboard have got to be darn close in CG terms to a "Sonex B" with 20 gallons and one of the heavier "supported" engines.

I'm glad to see that the good ideas keep coming from Sonex LLC, thanks to the whole team.

[N111YX]

I suppose we're all going to have to lower our heads now when asked and say "yeah, it's an old 'A' model".

I was hoping for Continental O-200 capability and a all up weight of 1300 lbs... :(

That would be the C model!

[Brett]

Just about ready to test fly my Sonex and I now want to cry with this announcement. More fuel and a Rotax option.

[NWade]

A few notes that I haven't seen anyone comment on:

• Weight: They claim they've worked to revise the structure to save weight, and that this will offset the increased size of the fwd fuselage.
• CG: They mention a different seating position, which is more-reclined. I bet is that this is not just to accommodate tall pilots, but is also meant to slightly adjust the CG. This would help offset the potential fuel and engine weight increases. A slightly different seating position not only affects where the pilot's weight is located, but it might also shift where the wing-spar comes through the fuselage. Such a change would also explain why you cannot convert a Sonex A-model into a B-model.
• On O-200's I'm not surprised this still isn't supported. Sonex has made it clear that they don't feel the O-200 adds any performance over an AeroVee or a Jab/Camit. Adding weight for no additional performance is pretty antithetical to most aircraft designers, Sonex included. I mean, do you see the RV-12 supporting an O-200 option? [Hint: No.]
• On a Gross Weight increase: Also not a surprise. Sonex has explained that G-loading is not the only factor they consider when setting the recommended gross weight for an aircraft. They factor in power-loading, stall-speed, power-off descent-rate, etc. None of the new engine options provide a significant change in the general power-loading numbers that you could already achieve with a Jab/Camit. And unless they build a new/different wing, the stall speed of a Sonex "B" model isn't going to be any better than the original. Finally, as a minor consideration, Sonex wants to emphasize the weight savings they've made in the changes to the "B" model. Simply setting a higher gross weight would provide ammunition to critics and skeptics who might simply accuse Sonex of providing a bloated aircraft that underperforms or is somehow unsafe with an 80HP engine on the front.

FWIW, I've really been building at a fast pace this winter and am nearing completion of my "A model". Seeing this news has been a bit deflating, as I think the "B" model is noticeably better than the 2010 kit I'm working to finish. I'm not upset at the company for improving their product, but I'm bummed that I cannot convert/upgrade; and I already have another airplane that I need to build (after the "A model" is done)... Maybe by the time I'm ready for my 3rd aircraft, Sonex will have a 4-seat model out? ;)

--Noel
Sonex #1339
TD, Center-Stick, Acro-ailerons, Flush Pulled Rivets, AeroVee Turbo
Wings & Empennage finished, Aft Fuselage nearly complete

[ihab]

Maybe by the time I'm ready for my 3rd aircraft, Sonex will have a 4-seat model out? ;)

The Airplane Factory (http://airplanefactory.co.za/) already has a 2-seat and 4-seat version of their Sling. The Glasair Sportsman (http://www.glasairaviation.com/sportsman.html) is a 2-seater upgraded to a 2+2. My suggestion to Sonex would be to build something like this:

viewtopic.php?f=35&t=2226

Ihab

[Stogie6]

There you have it. Now after I finish my Onex, I can start thinking about getting into a B-model Wiaex in a few years. One of the things I have discovered building my Onex with my dad is that I am becoming a builder.

Repeat offender... WOOT!

[ihab]

With the "Y" stick ...

So how do people fly with a center stick, "Y" or not? What happens if you need to reach something in the middle of your panel, or even towards the right side? Do you just reach over and hold the stick with your left hand for a second?

The dual throttles are cool, but does the center stick also make the dual-control nature a bit less "dual"? Let's say the flap switch, mixture control, etc. are mounted where I imagine they would be: to the left of the pilot, so (s)he can stay on the stick, let go of the throttle for a second, and manipulate them. To get to these controls, the right seat occupant must switch hands in order to reach over and operate them, which is a bit schlep.

Finally, how do the dual throttles work with Rotax engines? Rotax carbs have springs that pull them towards WOT, which I'm told means Rotax drivers have to keep messing with the friction in order to keep the throttle from "creeping" forward. Can this be done with a dual setup? For what it's worth, the Evektor SportStar uses a positive-lock "mixture style" knob for its throttle -- I think for this very reason.

Ihab

[LarryEWaiex121]

Ihab,

I have a friend with a single stick Waiex. Converted from two stick to save knee space and more comfortable.
Robinson has used this very control setup since day one in their helicopters with great success. Bound to save a bit of weight which makes everyone happy. I believe even Zenith uses this arraignment but I'm not 100% certain.
If had it all to do over on my Waiex and this option was available, I certainly would go this direction. I believe it makes perfect sense.
Back in 08 when I ordered my Waiex, there was no option other than twin sticks.
The twin throttle setup I really like. Although the center control has been around for quite some time I prefer the stick in my right hand and throttle in left. At least the twin setup allows for sharing, initiating prospective flyers and allowing the right seat guy some hands-on. Also much easier to get your flight review accomplished. Very few instructors want to ride in a plane with no real access to the throttle other than by reaching across.
My guy doesn't have an issue with it but he trusts my ability to get it on the ground right side up I guess:)

[fastj22]

The official announcement is now up at http://www.sonexaircraft.com/

Great, thanks!

First question: Why did Sonex not up the gross weight all the way to the LSA maximum 1320#? I guess my answer to myself would be: to maintain compatibility with the Aerovee. The Aerovee is Sonex's main tool for building a super low-cost aircraft.

That said, though, and perhaps as a result, the aerobatic gross weight allows only 330# of useful load, so with any reasonable occupants, it is still solo when aerobatic.

Ihab

The wing didn't change. Bumping up the gross above 1150 will increase the stall speed above LSA requirements.

Good improvements overall. the addition of the Rotax will certainly get them some momentum.

[fastj22]

I suppose we're all going to have to lower our heads now when asked and say "yeah, it's an old 'A' model".

I was hoping for Continental O-200 capability and a all up weight of 1300 lbs... :(

That would be the C model!

No, we will raise our heads and say we have the Model A!