flyrotary@lancaironline.net Mailing List Archive

Yes, you should read Tracy’s discussion. Also remember that the author of the post you sent was trying to sell the Powersport PSRU (for $6000 I might add). Interesting also that to my knowledge the PSRU that has truly failed were the early Powersport PSRU.

“Bill” implies that because the rotaries pulse is different from other engines it is somehow more damaging. The reality is that the pulse from the rotary is must softer and lasts for a longer angular portion of the rotation of the e-shaft. This makes the rotary much easier on a PSRU than a 4cylinder piston.

I suspect (thought I have no evidence) that Powersport neglected to counterbalance their engine in the early testing that “Bill” mentions.

Dave Leonard

You should read the discussion by Tracy Crook on the subject of torsionals in connection with his comments on the design of the Real World Solutions PSRU. See the web page at http://www.rotaryaviation.com/psru_development.htm

Design Philosophy Part 1 & 2 covers the topic.

-----Original Message-----
From: Greg Fuess [mailto:gregory_fuess@yahoo.com]
Sent: Thursday, January 22, 2004 9:23 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] FW: [VAF Mailing List] Engine Choice

Guys,

Forgive me for beating a dead horse about torsionals. I have been reading another list for (VAF and RV-7) ~2 years, and have anxiously anticipated installing a 13B, and now instead a Renesis engine, in my soon-to-start RV-7. Now, I am hearing things that cause me to question my ability to make a sound decision in this regard, as this is the first discussion of torsionals is the first I have heard. I am beginning to question my ability to follow through on what I had taken to be the best alternative engine choice.

I am therefore forwarding the most seemingly competent post (I am not enough of an engineer to evaluate this) regarding this issue. My first impressions were that rotaries were much less susceptible to torisionals that regular engines, but recently that view has come into apparently serious question, based on the statements below.

Appreciate your thoughts and comments.

Regards,

Greg Fuess