V-tail Study
This is an initial draft document subject to change without notice. Please excuse typographical errors etc. Any constructive input is welcome and appreciated. email
Ruddervator from a B35 Bonanza
A reskinned control surface has a weaker skin assembly, notice the corrugated grooves. The original skin has 1/16 of a inch deeper groove. The re-skinned ruddervator has a shallow groove and results in less strength or rigidity. Also in this area Beech added additional bracing starting with the 1957 H35. I have seen one earlier model Bonanza that had the bracing added.
Photo below, original ruddervator having a flat surface, again provides a stronger assembly and more rigid.
Here is a photo of a re-skinned ruddervator, notice the difference The skin is flexed outward or convex in shape, it doesn't allow the straight edge to lay flat. Also notice in the photo below how the skin has less pronounced ridges and grooves in its formation.
The added weight of the counter balance
assembly required after re-skinning imposes additional
loads on the red shaded area which is actual weaker after a re-skinning of the
ruddervator. The original counter balance lead weight is lighter weight.
Ruddervator from a B35 Bonanza
Below is a left side ruddervator on a G35 Bonanza with reskinned ruddervators that was involved in a flutter incident. Notice that the weak section completely broke apart from the remaining ruddervator assembly. This outer section of the ruddervator is weakened by the current replacement skins obtained from Raytheon. Our current Repair Stations have no control over this, It's just a bad product from the manufacture.
In this photo below, the counter balance assembly completely detached from the airplane. This is a right side ruddervator from a G35 Bonanza. There is another thing to look at in this photo, the trailing edge rivet line. It doesn't have enough rivets installed. Looks like the Repair Station skipped several locations.
See how the fuselage skin gets wrinkled
G35 Bonanza
In the photo below of a S35 Bonanza ruddervator, notice the additional internal bracing rivet line that adds strength and rigidity to the structure. Also notice the counter balance assembly, the pointed tip contains the lead weight assembly and is positioned more forward of the hinge line requiring less weight to obtain a proper balance than the early Bonanza ruddervators. This reduces the overall weight of the ruddervator assembly.
Notice the actual weight differences from the photo below. The counter balance lead weight on the left is used along with additional lead washers supplied by Raytheon to balance the ruddervator assembly within tolerance of the new specification limits. This heavier weight is needed to off-set the additional weight that is imposed from reskinning using new skins and parts from Raytheon.
Counter balance lead weights from a B35 Bonanza
SB 27-3358 Raytheon SB and AMOC to AD 98-13-02
NPRM 2000CE44
NPRM 93-CE-37
AD 98-13-02 (Vne speed restriction for 35, A35, B35, 35R)
AD 97-06-11 RUDDERVATOR DIFFERENTIAL TAIL CONTROL ROD ASSY
AD 94-20-04 EMPENNAGE INSPECTION & Balance check (All V-tail models)
AD 89-05-02 MAGNESIUM ELEVATOR CONTROL FITTINGS
AD 76-05-04 Stabilizer Attach Fitting inspection or replacement.
The Beech Accident NTSB report Page
Spokane incident NTSB # CHI97IA122 Model 35
NTSB reports
CHI97LA119 D35, near Mt. Sterling, Kentucky
September 1996, the right ruddervator and left flap had been reskinned due to corrosion.
December 1996, the pilot purchased the Beech D35 Bonanza.
December 1996. He reported that during the flight he experienced a vibration, but thought it was turbulence related since he was flying over the foothills of the Rocky Mountains. He had been flying at about 8,000 feet between 160 to 170 mph. He described the vibration as a "mild shudder," and did not think it was threatening.
January or February 1997, experienced another vibration incident. He was flying at 3,000 feet and he thought it was another case of turbulence. He did not experience any negative G's and he described it as a "mild shudder." He reduced power and the vibrations stopped. He did not have the tail of the airplane inspected after the two vibration occurrences.
On April 29, 1997, at 1330 eastern daylight time (EDT), a Beech D-35, N5985C, sustained substantial damage during cruise flight when it experienced tail flutter near Mt. Sterling, Kentucky.
more..... NTSB reports