>Did he get it flying?
Yes he did. Eventually he sold his plane for $129K. Sometime later, the new owner swapped out the 20B for a Lycoming IO-360. Beautiful example of a Velocity.
There is some good video out there that demonstrates how well his system worked.
https://www.youtube.com/watch?v=zxIKDnYZE24
I remember seeing some bar-napkin drawings that depicted the exhaust from each rotor going into a swirl collector then into a small can type muffler that allowed the gasses to pass through a series of washer-like baffles (similar to a suppressor on a firearm.) It appears to be quite effective.
Stuart Smith (Utah) actually fabricated a few of these but I can't locate him now.
T Mann
From: "Marc Wiese cardmarc@charter.net" <flyrotary@lancaironline.net>
Sent: Tuesday, July 21, 2020 10:09 AM
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Al Gietzen - 20B Exhaust System
This is the only one I could dig up that showed any of Al’s exhaust. Is Al still around? Did he get it flying?
Marc
From: Rotary motors in aircraft
Sent: Monday, July 20, 2020 11:45 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Al Gietzen - 20B Exhaust System
Does anyone have any of the drawings from Al Gietzen's exhaust system as it was installed on his Mazda 20B Velocity (N755V.)
Tom Mann
Long-EZ N200LZ (in construction)
Velocity N951TM