I was curious as to what the group thought about the older V-tail Bonanza. You can pick one up with engine and airframe times comparable to a Sundowner for about the same price as a Sundowner. How much more airplane is a V-tail Bonanza than a Sundowner? How much more are the average costs of ownership? What are the big pluses or minuses? What an I not considering?
David Grigg
This is based on an earlier post in MML. I’m going to make the comparison the Sierra vs. 35-series Bonanzas, as I have considerable first hand experience with those two as opposed to only light experience with the Sundowner. Most of the Sierra commentary will apply to the Sundowner, with a few exceptions. The Sundowner will be 10 to 15 knots slower than the Sierra, the fixed gear will cost less to maintain, and insurance will be less expensive.
While the oldest Bos are indeed faster than a Sierra by about 10 to 20 knots (depending on year), they do not have the truly usable payload of a Sierra (cubic feet, and front and rear seat payload capability), nor anywhere near the cabin size (in part that’s why they are faster). When you get up to the late 60’s and later, the speed disparity goes up to about 30 knots (some would argue for 35 knots). With typical options like a King 200 autopilot and flight director, most 35-series Bos cannot legally load the 4 seats even close to the same range as a Sierra. They run out of CG range capability well before running into max gross limits. I have taken up four people in the Sierra who could not be legally loaded in the Bo.
Bos are nowhere near as stable as a Sierra. Even in calm air it is common to see a 35’s wing tip constantly tracing a small figure 8, unless it is equipped with a yaw damper… which further restricts aft loading. While the FAA eventually blessed the 35’s certification a second time, there are many who believe that it remains right on the edge of stability for certification standards, and that this contributed to the upset problems… which in turn overstressed the tail structures. Several ADs addressed this issue, but they simply reinforce the tail; they don’t address the inherent stability issues in bumpy air.
I know that there will be variances involving specific people and specific planes. On average I believe that the cost of owning and operating a Bo would range from at least 200% to possibly 300% of the cost of a Sierra. This is based on eight years of actual numbers, as well as many conversations and articles. This assumes that the planes are in comparable condition, but probably not of the same calendar age. It includes purchase price, debt service, direct and indirect operating costs, and maintenance. It is excluding wild cards like a badly corroded spar. Most of the systems are very different; the Bo core design comes from the WW-II era, with many of that era’s design norms. One small example of cost differences: roll servo overhaul for the Sierra, $250; for the Bo, $1,000.
Bos have bladder tanks; electric gear with a complex mechanism; electric flaps with a similarly complex mechanism (central motor, separate cable drives to remote actuators); and a flight control mixer system (for the ruddervators) that has to be seen to be appreciated. They have typically been equipped with more complex and expensive
autopilot and avionics packages. Did you know that the wing leading edge, that contains the fuel tanks, is held to the spar with a full-length piano wire? Elegant while it works. Murderous if it has to come out, and breaks within the hinge. The rear bulkhead cover panel in a Sierra is one piece, and typically removes with two screws. Most Bos have that same panel made up of at least three pieces, sometimes more, and it can easily take an hour to get it off without damaging anything. It is more common than not for owners to have to top the IO520 engine in as little as 700 to 800 hours, and they rarely make their 1600 hour TBO. Compressions stay chronically low, with a primary culprit being premature exhaust valve leakage (they don’t have sodium-cooled valve stems). The 6-cylinder engine is much smoother than our 4-cylinder IO360, though.
I could go on and on like this. You have to have worked on both plane models to fully appreciate how much more time and effort has to go into properly maintaining a Bo. While airframe familiarity is important for any aircraft mechanic, it is critical on a Bo. Otherwise expensive problems will be missed, rigging will be incorrect (on gear, gear doors, flaps, etc., not just flight
controls), and history-based (rather than regulatory-based) preventive measures won’t get done (like uplock spring
replacement). You can take a Bo to one of the ABS Bonanza clinics, where engine and airframe experts will go over it with a fine-tooth comb. You’ll walk away with three pages of squawks, despite having had the plane maintained by an experienced person. There are so many pivot bushings, rod ends, and bearings that it sometimes seems like a constant replacement project to keep them all tight. You even have to know which way certain bolt heads face, as they are not all consistent with normal practice (forward and up); as well as which critical bolts must have the M-suffix part number (Magnafluxed), even though they look like standard hardware. This is because they are being utilized near their design limits, without the usual design margin, in the effort to hold down weight and size.
The 33-series Bos have slightly fewer drawbacks; the 36-series has a slightly different set of pros and cons as well. The relative ownership cost picture remains similar across all three models, relative to a Sierra.
No question that the V-tail has more ramp appeal, for those “in the know”. FWIW, in our long-distance travels to out of the way places, the Sierra has been mistaken for a straight-tail Bo in half the places we land. The Sierra drivers with the 3-blade prop probably get this even more than I do. Personally, I’m afraid I tend to lean more toward the practical side of ownership, rather than the ramp appeal side.
Hopefully this won’t have aroused any ire for the Bo lovers. Bos are certainly a classic design, with performance that has held up well against more recent designs. My opinion is that planes like the Cirrus SR22 finally outperform the Bo, but that’s what it took to do it (clean sheet design, 50 years later). I’m open to any corrections that anyone sees in my comments or numbers.