Path: csiph.com!eternal-september.org!feeder.eternal-september.org!nntp.eternal-september.org!.POSTED!not-for-mail From: Christopher Howard Newsgroups: sci.physics Subject: Re: force generated by propeller? Date: Mon, 02 Feb 2026 07:44:02 -0900 Organization: A noiseless patient Spider Lines: 24 Message-ID: <87cy2ndrjh.fsf@librehacker.com> References: <87h5s2iyw7.fsf@librehacker.com> MIME-Version: 1.0 Content-Type: text/plain Injection-Date: Mon, 02 Feb 2026 16:44:03 +0000 (UTC) Injection-Info: dont-email.me; posting-host="7729e7c5fa919ea81d758209eff22745"; logging-data="818522"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX182iGT3fhoSKp8J8y19O+Yxv6uUilAy+PE=" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:s+KLq3bRuFqUEP8ZdQvTLPRgDg0= sha1:QqFXKpBtZKElBUTPGkoRdX7EDVQ= Xref: csiph.com sci.physics:895031 Jim Pennino writes: > > There is a rule of thumb that a decent propeller makes about 20 lbs > thrust per 10 HP. Okay, thank you, that is helpful to know. > > Alternately Google "how to calculate propeller thrust". I don't use Google search, but DDG gives some results that are a bit difficult to wade through. The propeller thrust calculator page gives these equations: Velocity = Propeller Pitch * RPM * (1/1056) Thrust = (2 * Efficiency * Power * 746) / (Velocity * Propeller Diameter * 0.0254) with the Power in watts and the pitch and diameter in inches. That doesn't sound too complicated to calculate. -- Christopher Howard