Last updated: 23 September 2026
Short, readable, and meant in good faith. If anything here worries you, email hello@propshaper.com and we'll work it out.
PropShaper (propshaper.com) is a browser-based propeller design and analysis tool operated by Zach Backas. The free tier is the complete design loop: every design control, Quick design, performance analysis, stations, STL export of standard props, and sharing. Pro is a paid subscription for advanced output (STEP export, duct parts, STL of toroidal, ducted, skewed or raked props and blended tip sections) and unlimited cloud designs, described on the site at the point of purchase.
The service is not offered in Iran or Russia, and requests identified as originating there are denied.
Accounts are optional for designing and handled by Clerk; sharing to the Hangar requires signing in. Your designs are yours. Designs you share to the Hangar as public are listed publicly and openable by anyone with the link; unlisted designs are reachable only by their link. By sharing a design you grant PropShaper the right to host and display it as part of the service. You can delete your designs, your shares and your account at any time.
Pro billing is processed by Stripe. Subscriptions renew automatically until cancelled; you can cancel, switch plans, or view invoices any time via Manage billing, and cancellation takes effect at the end of the paid period. Prices may change with advance notice; feature gating changes are announced at least 30 days before they take effect.
PropShaper produces model-based estimates, not certified engineering. Propellers store real energy: a failed blade can injure people and damage property, in the air and in the water. You are responsible for validating any design before use, for printing/manufacturing quality, and for complying with the rules that apply to your aircraft or watercraft. The service is provided "as is", without warranty of any kind; to the maximum extent permitted by law, liability is limited to the amount you paid for the service in the preceding 12 months.
Don't abuse the service: no scraping accounts, no attempting to break gating or other users' data, no illegal content in shared designs or names. The public API is offered for reasonable usage and may be rate-limited.
These terms are governed by the laws of California, USA. If a clause is found unenforceable the rest stands. Continued use after a posted change means acceptance; material changes will be announced.