I checked Out The $40,000 Saberwing Airplane

This past week I had a great time talking to Bill at Azalea Aviation about The Saberwing aircraft. For those who are not familiar with this airplane, it's a 2 place experimental that uses a Corvair engine. Climbs at 500 ft - 750 ft per minute and cruises @ 150 mph, burning 5-6 gallons of fuel.

The video below is just a quick walk through


Here are my honest initial impressions.

Engine: I've always been skeptical about auto conversion engines but I was shockingly surprised on how smooth the corvair engine was. Could barely feel any vibration in the cabin on climb out or cruise.
And the engine sound of this aircraft is so sweet. You'd have to be on the ground in person.

Cabin space: I'm 5'10, 170 lbs and I found the cabin space to be quite comfortable sitting and flying from the passenger side. For 2 mid size adults, you have more than enough ample space here.

Performance: When I first read the numbers for the Saberwing, I had to see for myself. And during my flight, I saw north of 160 mph and we were barely at 3500 ft. The prototype aircraft did have a 120 HP turbo engine in it that's currently being tested.

Behavior: I only got a bit of stick/rudder time. The aircraft was fairly easy to maneuver. Better to have fingers on the stick rather than a grip. Barely needed the rudder to turn.

Build material: The aircraft is built in wood/composite. Still not sure how I feel about wood yet given weather and longevity. But I'm still a baby when it comes to aviation, lots to learn. The air frame did appear to be solid and well put together

All in all for $40K, this is a very intriguing aircraft

 

Not bad for 40k!

Only thoughts, I wonder why they didn’t go with a Subaru conversion and also using wood, not a fan, especially if it’s the spar.

 

One of the guys behind the project is Bill Clapp, who is a long time Corvair guy. He sells Corvair parts, services, and maybe entire engines. The plane was developed around the Corvair conversion.

 

The Saberwing brochure says a "budget" finished Saberwing can be built for $45,000, but most will see a final cost of $50,000.

It's certainly an interesting design that can be built as an LSA or a heavier and faster EAB, but for $50,000 you can buy a nicely equipped low time used factory built SLSA.

The wooden spar shouldn't be an issue with today's penetrating epoxy resins to seal the wood at the optimal moisture percentage while presenting a barrier to termites and dry rot.

Maybe it's that a marketing person wrote the brochure, but calling Useful Load "Usable Weight" and a few other terminology missteps are a little disconcerting.

 

Those are probably the average numbers. I spoke to one of the builders who went from kit to flying @ $42,000

 

Yeah, I don't doubt a good scrounger could get the cost down that low.

 

You can put a Subaru engine in it if you want. Probably set you back around the same price as the Corvair engine. I've seen the Subaru mounted on a seaplane and that thing is awfully quiet.
As per the wood frame, here is the response from Azalea Aviation: "We went with wood because it is a known spar design with zero failure to date. The main spar is a boxed spar made of spruce and good to 6Gs plus design. We plan on a demonstrated destructive test soon. The spars are pre-made in-house under careful watch. When installed they just need to be sealed with epoxy coat. The insides are already coated."

 

I think there have been some wood spar failures

 

Knute Rockne was unavailable for comment.

 

Bill is a Corvair guy, and has been involved in flying Corvairs for a very long time. Essentially this airplane was built around a Corvair. Additionally, this airplane was designed with simplicity as a major design parameter. A direct drive 120HP air cooled engine is insanely more simple than a liquid cooled, geared, computer controlled Subaru.

I am flying behind a 120HP Corvair that I pulled out of a 1965 Corvair myself, disassembled myself, cleaned myself, and completely built myself. Using conversion parts of course, but I turned every bolt, fit every bearing, etc. Additionally, I installed this in an airplane that did not have factory support for this engine, so all firewall forward was essentially off of the plans and of my own design. I never would have been comfortable doing this with a Subaru.

 

I read their statement as this wood spar design has had no failures. Not that wood spars in general have had none.

 

I think I would prefer "the only spar failures we've had, have been in tests to failure and they failed well beyond the rated G-load" instead of "well, we haven't had any failures yet". I'm just sayin.

 

Yeah, I can't help but wonder how many Saberwings are flying and how many hours they've accumulated. Wikipedia says there were two completed as of 2017.

 

Exactly. Saying we've never had one fail is kind of like saying I asked every one of my friends if I'm ugly and both of them said no.

 

Possibly. But if they borrowed (reused sounds nicer) the spar design from another aircraft it might be many thousands of hours with no failures. I can’t tell from here.

 

Applies to the aircraft they borrowed the design from only in that case. As any home builder will tell you, change one thing and you have to change lots of things. Borrowing the design from another aircraft is all well and good. But the safety record means absolutely nothing once you build an aircraft of a different design with it. Maybe the tail has never come off a 172 but copy the design and build it into your knock down drag out aerobatics monster plane and things could be different.

 

Fair enough.

 

I believe his aircraft was originally based on the KR2S designs.

 

And some made of metal as well.

Re-read their statement. "We went with wood because it is a known spar design with zero failure to date."

Known spar design = has been used in other aircraft. Many wing designs fall into the same category. In any case, they plan to perform the testing you all desire.

The Focke-Wulf Fw 190 had a wooden spar that was capable of more than the pilot could stand (>10g). A friend is building one of these and the spar is amazing.

 

A wood spar is a major draw back to many in the industry

 

I was thinking it looked a lot like the KR2.

 

So are Subaru engines and steam gauges and glass cockpits. Opinions don't trump facts.

 

Engine fails I’ll make it work
Instrument failure, whatever
Spar failure, morte

 

The late, great Tony Bingelis wrote extensively for EAA publications on experimental amateur built airplane construction, and this article about wood wings notes that many famous aerobatic designs feature wood spars including multiple Curtis Pitts models, the Christen Eagle, the Acro Sport, Skybolt, One Design, F8L Falco, etc.

Wood Wings by Tony Bingelis originally published in EAA Sport Aviation, January 1996.

 

That was a very good read. Thanks for sharing.

 

Here's another EAA Sport Aviation article from May, 2000.

Wood for Wings: Building with nature's composite by Mike DiFrisco.

 

You learn something new every day. I never would have guessed that Fw 190's had wood in the design.

I saw both of the flying (at that time) saberwings at OSH 17. Pretty cool, but awful low to the ground. I wonder if they have prop clearance issues when operating off a not so smooth grass surface.

 

I noticed in the video posted on the other thread that on take off roll, instead of picking the tail up as is normal for tailwheel ops, the tail wheel was kept on the runway until the plane flew itself off. Its been stated, that the gear legs can be made longer for better prop clearance. What I'm struggling with is understanding why anyone (including the builder of the prototype) wouldn't do that. Do you lose that much performance by adding a foot to the gear legs?

 

I noticed the plane pictured in the first post has a 3-bladed prop, while the plane in the pdf brochure has a 2-bladed prop. The 3-bladed prop has shorter blades with better prop ground clearance.

I'm having trouble finding any reference to wooden spars in the Fw 190. I found a reference to wooden flaps in lieu of aluminum in Fw 190s built toward the end of the war to cut down on the use of strategic materials.

 

Just to close the loop, it appears the Focke-Wulf Fw 190 had an all metal wing. The wing was fully cantilevered and built around the front spar which ran from wingtip to wingtip. The three web center section "joggled" aft to provide room for the retracted main gear. the spar sections between the center section and the outboard sections had a double web, and the outboard sections had a conventional I-beam single web. The rear spar was I-beam.

 

I see where a Saberwing has crashed in south Georgia, the pilot was from Colquitt County, near where they are built, died in the accident and officials say the plane had lost parts, the area is over a mile long, RIP pilot/owner

 

A few metal ones too, as I recall.

I am a fan of wood if it is properly engineered and one wants to build an economical airplane; something needed to get more people involved in aviation imo. This entire airplane seems like it can be built for not much more than the price of a new Rotax in the crate. That's pretty impressive in my books.

 

When I think about wood and WW2 airplanes, first to come to mind is the Dehaviland (can't spell it) Mosquito

 

Yep, that airplane is listed as serial number 3.

 

Sadly you are correct Gary. The pilot you speak of was Larry Bothof. We met during my shoot at Azalea Aviation. Amazing guy, still can't believe he's gone. Hope y'all keep his family and friends in your prayers.

 

de Havilland

Named after the founder, engineer and pilot Geoffrey de Havilland.

The Mossie's predecessor, the 1934 DH88 Comet long distance racer, now in the Shuttleworth Collection:

 

And thousands of Champs and Citabrias and Taylorcrafts...

 

Kathryn's Report article about the accident. I see Kenny has already commented.

http://www.kathrynsreport.com/2018/12/azalea-saberwing-n203sw-fatal-accident.html

 

Not to mention a Cessna twin with wood spar, wood ribs, wood leading edges, and fabric covered.

 

I suppose I'm a sort of accident junkie; I have several books on the subject (but the internet made it easier!) This particular SW flew > 100 hours then was modified with a larger engine and larger tanks (you can see on his FB post the wings opened up.) It will be interesting to learn the cause of the in-flight breakup.