Ruddervators

Original ruddervators from Beech were assembled by a process using spot welding instead of riveting. This saved a considerable amount of weight in a place you didn't need it. However, over the years, Beech decided that it was "OK" to repair or re-skin the ruddervators and use aluminum rivets on the trailing edge. Of course this has been a debatable subject ever since. The only ruddervator skins that were used originally and have to be used today because of the strength and light weight is magnesium. The extra weight is from the added rivets that Beech didn't use when originally manufactured. Their are now AD's related to a few incidents and accidents involving tail flutter. It is suspected that the extra weight on the ruddervators from reskinning and assembling with the "Beech Approved Process" using aluminum rivets may be an issue.

Here are some of the NTSB reports (click here)

Currently you can't get an original spot welding construction ruddervator from Beech. There are a few shops that will order the new magnesium skins from Beech and repair your original ruddervators assembling with rivets and more counter weights. It is my quest to source original manufacturing using spot welding instead of rivets on these ruddervators. Yes spot welding magnesium is not a common practice or available just anywhere.

Here is an article regarding spot welding magnesium (which is on the return for aircraft production instead of rivets.  (click here for article)

Initial comparison testing of  ruddervators

One ruddervator is factory original the other has been re-skinned utilizing rivets for assembly. These assemblies were confirmed to be in balance corresponding to the current Beech methods and current AD's and SB's. Both assemblies balanced to 18 inch-pounds.

Ruddervator counter balance assembly weights.

      Re-skinned             Original
      3 lbs 1.8 oz.         2 lbs 7.4oz.        Difference = 10.4 oz.

Ruddervator assembly with trim tabs (minus counter balance assembly
listed above)

      Re-skinned             Original
     4 lbs. 13.8 oz.         4 lbs. 12.6 oz.   Difference = 1.2 oz.

                                                   Total difference = 11.6 oz.

So how much does a increase of weight matter ? Well, consider where it is located, if you measure out from the attached support base of the stabilizer assembly to the counter balance assembly you should see approximately 70" distance. You multiply the 70" times .65 lbs. (equivalent to 10.4oz) and you get 45.5 inch-pounds! It only gets worse when you add the other 1.2 oz. of  increased weight to the equation.