I am a Mechanical Engineer and a retired University Professor.
I can help you with Mathematics, Algebra, Calculus, Physics, Static Equilibrium of Solids or Static Mechanicals, Dynamic of Solids or Dynamic Mechanicals, Mechanical of Materials or Strength of Materials, AutoCAD and Application of Computer Tools on Engineering Problems.
I'm just going to make you a straightforward offer:
1. You tell me what you want made via PM, providing a question or problem as example
2. I tell you a general estimate of time and cost required
3. We fix a cap and several intermediate steps of interaction
4. I will make watermarked iterations of partial job. You pay me in accordance with the partial job to $20/hour in BTC
5. Once the job is finished you pay me the restant of $20 in BTC for every hour I spend in it and I send you the finished job without watermarked