Recent posts about anti-servo tabs reminded me of this sad story from 65+ years ago.
An older acquaintance’s (met him when flying him as a student sky diver) father got interested in homebuilts. He had no experience building, and wasn’t a pilot. I did convince him to join the almost-local EAA chapter that was almost 100% builders. They gave him advice, but it turns out that he knew everything. All the fuselage truss welding was done with a huge OA torch, and the welds all looked overly crisp, to be kind. (I had offered him the use of a Victor aircraft torch.) As he was nearing completion of the Smith Sidewinder, he still had not received the plans for the pitch control linkage. I was headed to Oshkosh, so he asked me to speak to Mr. Smith about when the plans, which had been purchased more than a year previously, would be 100% done. I did, and was told something along the lines of “Go play with yourself!”
The local builder went ahead and “designed” and built his own pitch control system. I stopped by, and saw two very significant deficiencies: the control linkage to the stabilator was an aluminum rod so long and slender that it sagged a few inches in the middle, and the anti-servo tab was installed as a servo tab. I was unsuccessful in all efforts to convince him that what he had done would be a problem. I asked him to touch base with the professional aerospace engineers in the chapter. He chose not to.
He had gotten a Private Pilot Certificate in a C150, so he was ready for the initial test flight. I wasn’t in town to see it, but I heard from several pilots who did. Upon rotation, the aircraft pitched radically nose up, then nose down and slammed into the runway. He repaired the damage, and a few months later, the local ace instructor, who had seen the wreck occur and had diagnosed PIO, attempted the next flight. He lasted through 6 or 7 pitch cycles before smashing into the runway. The aircraft was disassembled and returned to the workshop, never to be flown again.
Sad, but true.
Please share your stories.
BJC
An older acquaintance’s (met him when flying him as a student sky diver) father got interested in homebuilts. He had no experience building, and wasn’t a pilot. I did convince him to join the almost-local EAA chapter that was almost 100% builders. They gave him advice, but it turns out that he knew everything. All the fuselage truss welding was done with a huge OA torch, and the welds all looked overly crisp, to be kind. (I had offered him the use of a Victor aircraft torch.) As he was nearing completion of the Smith Sidewinder, he still had not received the plans for the pitch control linkage. I was headed to Oshkosh, so he asked me to speak to Mr. Smith about when the plans, which had been purchased more than a year previously, would be 100% done. I did, and was told something along the lines of “Go play with yourself!”
The local builder went ahead and “designed” and built his own pitch control system. I stopped by, and saw two very significant deficiencies: the control linkage to the stabilator was an aluminum rod so long and slender that it sagged a few inches in the middle, and the anti-servo tab was installed as a servo tab. I was unsuccessful in all efforts to convince him that what he had done would be a problem. I asked him to touch base with the professional aerospace engineers in the chapter. He chose not to.
He had gotten a Private Pilot Certificate in a C150, so he was ready for the initial test flight. I wasn’t in town to see it, but I heard from several pilots who did. Upon rotation, the aircraft pitched radically nose up, then nose down and slammed into the runway. He repaired the damage, and a few months later, the local ace instructor, who had seen the wreck occur and had diagnosed PIO, attempted the next flight. He lasted through 6 or 7 pitch cycles before smashing into the runway. The aircraft was disassembled and returned to the workshop, never to be flown again.
Sad, but true.
Please share your stories.
BJC
