[FPSPACE] don a. nelson nasa retired engineer

[howard hoffman]

greetings:  is it possible that anyone would know how to contact don nelson. i am a retired aircraft mechanic , and i have questions. i was shocked that the shuttle airframe was manufactured out of 2024 and 7075 aluminum alloy , same as most of the aircraft i worked on , such as boeing 737 , 727 , dc9 , and md80 aircraft. when i say i was shocked , it is not a problem using these materials , but to use them directly underneath the thermal protection tiles and carbon fiber is a very big            """"     no - no   !!!!      """"      i say this as we all know that aluminum structural strength is limited to around 300f to 500f  degrees.  but if the shuttle had been manufactured using combinations of stainless steel , titanium , and most important , tantalum ,  do not misunderstand!!! all i am saying is this. the shuttle design of using 2024 and 7075 aluminum for weight saving is safe as long as these high strength , high temperature metals are used as an additional insulator against those 3.000 degree temperatures. especially the leading edge of the wings. here i would use stainless steel rails and webs. cover this with titanium sheet. finally a tantalum sheet over top of this. not one tantalum sheet , but three , four , or even five sheets of tantalum. probably three sheets of tantalum would be allowed , but the end result of all of this is that if the thermal tiles on the leading edge were to fail ,  i am cetain that these tantalum sheets would survive. i am also certain that the titanium sheets under the tantalum would survive. finally the stainless steel structure would maintain strength.  i am not a engineer ,  but i believe that the term ,,,,,      """"" fail-safe""""""  is what i am talking about. when the sr-71 blackbird program was designed , they went the extra mile to ensure the safety of those pilots , even to the extreme measure that if they had to bail out at 2,000 mph , that they would not burn up , and at 15,000 feet they could open their parachutes ,  and i am not seeing the same concern for these astranauts. i think that on the next flight , george bush should go up , and if he feels it is not safe , then i suggest that the shuttle be grouded until modifications are done. so if you read my letter , mr. don nelson , my name is howard , and my phone number is 412-264-2313.      sincerely ,,,,,,,,, howard from pittsburgh,pa
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