Abid
AR-1 gyro manufacturer
- Joined
- Oct 31, 2011
- Messages
- 6,257
- Location
- Tampa, FL
- Aircraft
- AR-1
- Total Flight Time
- 4000+ 560 gyroplanes. Sport CFI Gyro and Trikes. Pilot Airplane
Thank you. All is forgiven.
If by "Aluminum aircraft structures that were made with 2.0 x safety factor are flying around 50 years later" you were speaking of airplanes, I don't think such can be compared to a dynamically moving gyroplane mast. AutoGyro masts can crack elsewhere than the engine mount weldment. AutoGyro has a Service Information Letter about it: AG-SIL-2017-01-A-EN – Calidus frame upper mast side plate. I agree with you that their welding technique is to blame (albeit partially) after looking at photos of that new Calidus 83-AMW crash in France during take-off back in 2014.
It all depends. If you are going to make a mast stiff and provide no spread out point of release then the vibration will cause cycles concentrated in a spot that will fatigue. Anyway, Aluminum masts are not welded and changing them is more simple. Normally operated 304 Stainless of 14 gauge 2 inch square can last over 4000 hours+.
The Calidus upper mast plate weld that you are talking about is designed that it is more likely to crack. The bottom is longer and clamping points are 4 inches apart and the upper side welded is only 2.5 inches tall. They should be of about equal height. They will have a lot less chance of cracking and the plates should be welded with back purge inside upper mast tube. Anyway, that's AutoGyro's problem.