231 versus S35

[jetdriven]

50 minutes ago, KLRDMD said:

https://airfactsjournal.com/2012/06/tail-tale-what-was-wrong-with-v-tail-bonanza-pilots

"When the Bonanza came out in 1947, it was unlike anything else. It was aerodynamically clean and the very first ones would cruise 175 mph with a 165-horsepower engine. 
 

 

. That means that most Bonanza pilots were not used to such a clean airplane that was not stable in roll. 

Spiral instability and the aircraft cruises very close to its redline airspeed. Easy to exceed the redline airspeed and pull the tail off. They fixed the tail but not the spiral instability. Training and recurrent can mitigate most of that. 

[BKlott]

 Myth: It’s the Pilot’s fault. All of these airframe failures were the fault of the Pilot who was invariably a Doctor.

Reality: Error prone Pilots must have only flown the V-tail model and not the straight tail model.

Again, the facts from the report:

The Problem
The statistics leave little doubt that the V-tail Bonanzas have a safety problem not shared by their straight-tail counterparts. Over the years there have been more than 200 fatal in-flight breakups in V-tails (as of 1978). There has been just one in a straight-tail Bonanza.
The Aviation Consumer's 1979 study of in-flight breakups during the years 1964-77 showed the V-tail to have a rate of 0.65 breakups per 100,000 flight hours, compared to just 0.03 for the straight-tail 33 and 36 models combined.
Early in 1979 the FAA released a study of aircraft dynamic characteris­ tics. This study (see The Aviation Con­ sumer, May 15, 1979) took particular interest in the in-flight failure rate of the Bonanza. Over a 10-year period the FAA report noted that “the Beech 35’s in-flight airframe failure accident
rate, at 0.779 per 100,000 hours, is 20 times that of its straight-tailed compa­ nion and, in fact, is exceeded only by a few aircraft with substantially less
exposure ...
In May 1979 the NTSB released its
own study of general aviation accidents (report No. NTSB-AAS-79-1). Even though they did not separate V-tail from straight-tail Bonanzas, they found their combined in-flight failure rate to be “considerably higher than the mean rate of the selected aircraft group” for the five-year period studied. NTSB then commented, “It is significant that all 40 of the in-flight airframe failures of the Beech 33/35/36 involved the V-tailed models (Beech 35). Obviously attention should be focused on this model.”
Three studies—an NTSB study of five years of data, an FAA study of 10 years, and an Aviation Consumer study of 14 years of accident data—have all
shown the same fact. Yet this is not
the first time in the history of the Bonanza that this failure pattern has been observed. The evidence suggests that both Beech and the FAA have studied it extensively over the years and should have long been aware of the problem.
Chinese Water Torture
The first in-flight failure of a Bonanza occurred in 1946. During a dive test, an experimental prototype, serial number D-4, disintegrated. The observer parachuted to safety, but the pilot was killed. In the years since, there have been fatal in-flight airframe failures in every year for which data are available. As of 1978, the total of known in-flight failures of V-tail Bonanzas was 208. There was one straight-tail failure.
We do not know how many people died in these 208 accidents. However, if a sample of recent data is represen­ tative, there have been about 2Vi deaths per in-flight failure. We estimate approximately 500 deaths in Bonanza in-flight breakups. Thus,
probably twice as many people died in V-tail structural failures as in
the worst U.S. air disaster in history, last year’s American DC-10 crash in Chicago.
Like Chinese water torture, the bad news has trickled in over the years. Bad years, like 1953 with 14 accidents, were sometimes followed by relatively good years, such as 1954 with three ac­ cidents. Such swings must have en­ couraged apprehensive Beech designers. They were not idle. Beech made several significant structural changes to the Bonanza design as they tried to chase the gremlins out of the wing, the fuselage, the tail.
The external posture Beech adopted (and to a large extent, their internal one also) was that these accidents were due to pilot error, pure and simple. Meanwhile, Beech kept beefing up the airplane, but they did little for Bonan­ zas already in the field as they strengthened subsequent models.
 

My comments: There was a program to modify the original 35 with structural improvements to correct design issues that Beech discovered. These aircraft were re-designated as Model 35R. I believe that there were 13 of them. None of the improved aircraft experienced an inflight airframe failure.

If the airplane is up to specification (something that needs to be regularly checked and maintained) and is operated within it’s limitations, it should be perfectly fine. The problem is that so many of the airplanes have been found to be out of spec over the years and that is where you are exposed to having an issue. Ruddervators that are out of balance or become out of balance, control and trim cable tensions that are not correct, fuselage rear bulkhead cracks, fuselage skin that is no longer as thick as it used to be or is supposed to be, etc.  This is what you are dealing with. No, Beechcraft did not foresee the effects of twisting loads being placed on the tail spars and that is why the tail cuffs came into being.

All the concerns about the center section and wing spar cracks were probably overblown because the wings typically failed outboard of the landing gear mounts and landing light location, WS 66, where there was no spar web until the later, beefed up models.

I read somewhere that Ralph Harmon, who was involved in the design of the V-tail, was also responsible for metalizing the Mooney. He wanted to make sure that the Mooney was overbuilt (built right) and not something that JUST made Certification standards.

 

 

[0TreeLemur]

8 hours ago, aviatoreb said:

Them is negative g's!!!

[aviatoreb]

1 hour ago, Danb said:

Oh Erik Erik Erik, I’m in the minorityI guess, knowing this is a Mooney site regardless you’ll not find me purchasing a Bo, Cirrus or Cessna , I still have to look at those slow albeit uncomfortable airplanes to me. Remember the name of the site..

 

 

 

 

Shhhh... I was trying a new “strategy” as he said ... his slower airplane with bad  leg room is clearly better.  And history of any problems was the pilots’ fault.  He’s better looking and smarter too.  

I’m selling my mooney to buy a beech.

Edited September 2, 2019 by aviatoreb

[0TreeLemur]

To me, the feel of a Mooney C is that of a larger airplane.  The maneuverability is not what I like about it.   The PC system creates a "rock solid" feel in IMC that I really like.   Trimmed out in flight, she'll fly straight and true for 30-60 seconds at a time, even in mild turbulence.  With the Accutrak engaged in magenta-line following mode, I can slide the seat back to "economy plus" and pretty much enjoy the ride with occasional altitude adjustments.

[xcrmckenna]

Thanks for the info. Lol, you lost me at 12 gallons an hour. I’m pretty happy with 1010lbs of useful load my J has. Never flown in a Bo but I’m sure they are nice aircraft.


Sent from my iPhone using Tapatalk

[jetdriven]

Actually I think it was Beryl dshannon who invented the tail cuff. None of his had crashed, later Beech adopted the cuff as a fix.  And it was. Almost none have crashed due to tail deflection and subsequent structural failure. 

[0TreeLemur]

13 minutes ago, jetdriven said:

Actually I think it was Beryl dshannon who invented the tail cuff. None of his had crashed, later Beech adopted the cuff as a fix.  And it was. Almost none have crashed due to tail deflection and subsequent structural failure. 

Another/similar person was Mike Smith in Johnson City, KS, who was legendary for having recovered a failed V-tail, and after studying it developed a certified mod.

[cliffy]

3 hours ago, 0TreeLemur said:

Them is negative g's!!!

All in all it's only about 2 negative Gs  :-)

[jetdriven]

9 hours ago, 0TreeLemur said:

Another/similar person was Mike Smith in Johnson City, KS, who was legendary for having recovered a failed V-tail, and after studying it developed a certified mod.

You’re correct. It was smith’s mod. I think BDS bought it later.  

[Browncbr1]

I think the vtails look great and climb and cruise is great, but the wag makes me sick, the bubble windscreen and high side windows make me sweat, and stability in IMC sucks comparatively.   Travelair is the same way.  Those two are very difficult to fly by hand in bumpy imc.  However A36 and be58 have great imc stability.  

[0TreeLemur]

10 hours ago, cliffy said:

All in all it's only about 2 negative Gs  :-)

Yes.  But it is only certified to -1.5 to +3.8.   Flip it over and you could have 54 people standing on the bottom of the wing (not sure how one would pull that off). 

[CWM20f]

The gentleman’s father I purchased my F from was a crash investigator for aviation. They both were pilots.   After years on the job he purchased a Mooney.  His biggest reason was that the Mooney didn’t shed parts if an unfortunate incident occurred.  He passed the aircraft on to his son and I purchased from him.   He shared many interesting stories with me about structure, efficiency, speed, etc but never mentioned inferior handling compared to other aircraft (especially the V tail).   If I had only known ! 

 

[smccray]

On 8/31/2019 at 3:56 PM, KLRDMD said:

Climbing out at 110 KIAS, just me and full fuel I was getting about 500 FPM climb. I did pull the power back to 35" at about 1,000 ft to slowly transition to 75% power as the IA wanted me to. Flying the Bonanza later I got 800 FPM at 110 KIAS and it was probably 5º warmer by then. Interestingly the fuel flow was identical. I knew this previously but the TSIO-360 at 210 HP in the Mooney and the IO-520 at 285 HP in the Bonanza, full rich each burn 25 GPH in climb. I climb both at 110 KIAS but get another 300 FPM in the Bonanza.

This is interesting to me. Any of the engine whisperers care to weigh in?

My assumption is that the higher fuel flow is needed at full throttle to provide adequate detonation margin as compared to the NA io520 (same issue with the TN kit on my A36). I also assume the 8.5:1 compression ratio vs the 7.5:1 in the tsio 360 also plays a part in the difference.

 

[thinwing]

Well back to the flight comparison...some important points are missing in comparing the two designs.The bonanzas flap is much more effective than the Mooney’s simple hinge.Combined with its oleo struts ,landings are much easier and better for short fields.The design is much more forgiving  compared to Mooney’s attempts at 10 kts over with a tendency to bounce with prop strikes.Construction of the Bonanza reveals poorly designed elevator hinges...a simple steel stamped fitting with a an bolt...very wear prevalent...a constant hassle on my similarly hinged Baron.The 33/35 magnesium Elevator  (ruddervator)skins are prone to corrosion (magnesium is a very reactive metal)Skins are not currently being manufactured ,nor is even the magnesium sheet currently available.Parts costs have always been breath takingly high on Beech products...though Mooney is learning fast!9 years ago Mooney charged me 900 for a complete instrument panel,painted matching grey and placards pre silk screened.Remember those Baron elevator brackets I kept replacing???200 a pop for a simple sheet steel u bracket.Now my  hangar partner tells me they are over 500 for his A36.The Baron tail was prone to flutter at high speed and I could tell it was time when I could feel it in the yoke.My Bravo uses a captured ball bearing design covered with gap seals...very nice.My Bravo handles xwind landing better,not nearly requiring the control imputes.It is very stable in both roll and pitch...much easier to hand fly on instrument than either bonanzas or Barons.A vtail in bumpy turbulence ,on long flights really requires a yaw dampener!Back seat passengers have gotten sea sick with the incessant tail wag.This is not seen in the straight tails nearly as much so this points to a longitudinal instability.(An extreme example of this is shown by installing floats to an airframe,instant instability in yaw)Both my Bravo and the Baron it replaced were very similar in speed at 12 k.

[gsxrpilot]

I've never flown a V-tail. But I fully intend to get a ride in @KLRDMD's one of these days. I do have a bit of time in a 310hp F33A as well as some A36 time. I can't fault any of the Bo's and believe they are better at certain missions than any Mooney. But then there are certainly situations where the Mooneys beat just about anything in the sky. 

When it comes to personal preference, it's a Mooney for me. And with time in the B, C, E, J, 231, 252, Bravo, Ovation, and Acclaim type S, I'll take the 252 every time as my favorite.

On another note from this thread, there are three members here who no longer fly Mooneys, but who each have a wealth of Mooney knowledge, and other airplane wisdom as well. And this forum would not be nearly as valuable without their regular and continued contributions here. 

@KLRDMD, @Yooper Rocketman, and @M20Doc we need you gentlemen here contributing your knowledge, expertise and wisdom on this forum no matter what you own or fly.

[Yooper Rocketman]

8 hours ago, gsxrpilot said:

I've never flown a V-tail. But I fully intend to get a ride in @KLRDMD's one of these days. I do have a bit of time in a 310hp F33A as well as some A36 time. I can't fault any of the Bo's and believe they are better at certain missions than any Mooney. But then there are certainly situations where the Mooneys beat just about anything in the sky. 

When it comes to personal preference, it's a Mooney for me. And with time in the B, C, E, J, 231, 252, Bravo, Ovation, and Acclaim type S, I'll take the 252 every time as my favorite.

On another note from this thread, there are three members here who no longer fly Mooneys, but who each have a wealth of Mooney knowledge, and other airplane wisdom as well. And this forum would not be nearly as valuable without their regular and continued contributions here. 

@KLRDMD, @Yooper Rocketman, and @M20Doc we need you gentlemen here contributing your knowledge, expertise and wisdom on this forum no matter what you own or fly.

Ya, but I'll be back.  Might be able to work out a trade for a real nice 252 with a guy from Texas (oh no, now Denver) that's looking for the next step up when this old man needs to step down a bit in speed. 

Tom

[Bob_Belville]

24 minutes ago, Yooper Rocketman said:

Ya, but I'll be back.  Might be able to work out a trade for a real nice 252 with a guy from Texas (oh no, now Denver) that's looking for the next step up when this old man needs to step down a bit in speed. 

Tom

Tom, I'm sure you know that Thomas Wolfe really said "you can't go back".