# Considering a Ultra Prop II 3 blade 66 diameter for AeroVee 2.1 80hp

**URL:** <https://sonexpilots.org/t/considering-a-ultra-prop-ii-3-blade-66-diameter-for-aerovee-2-1-80hp/5905>\
**Category:** Aerovee\
**Created:** [August 18, 2026, 3:25pm UTC](https://sonexpilots.org/t/considering-a-ultra-prop-ii-3-blade-66-diameter-for-aerovee-2-1-80hp/5905 "2026-08-18T15:25:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![scdenny](https://sonexpilots.org/letter_avatar_proxy/v4/letter/s/ec9cab/32.png) [@scdenny](https://sonexpilots.org/u/scdenny)\
**Post date:** [August 18, 2026, 3:25pm UTC](https://sonexpilots.org/t/considering-a-ultra-prop-ii-3-blade-66-diameter-for-aerovee-2-1-80hp/5905/1 "2026-08-18T15:25:46Z")

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Has anyone used an Ultra Prop II 3 Blade 66 inch diameter for Aerovee 2.1 80hp and being installed on a Zenith 701?

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**Author:** ![Bryan\_Cotton](https://sonexpilots.org/user_avatar/sonexpilots.org/bryan_cotton/32/760_2.png) [@Bryan\_Cotton](https://sonexpilots.org/u/Bryan_Cotton)\
**Post date:** [August 18, 2026, 4:39pm UTC](https://sonexpilots.org/t/considering-a-ultra-prop-ii-3-blade-66-diameter-for-aerovee-2-1-80hp/5905/2 "2026-08-18T16:39:43Z")

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For the RPMs the AeroVee turns, 66" seems like waaaaay too much diameter. Peak power is at 3400 RPM and normal cruise is 3000-3400 RPM per the manual. Most AeroVee props are 54" diameter. At 66" if you do the math you may find the tips are transonic or supersonic.

Edit: I found this table.

 ![image](https://sonexpilots.org/uploads/default/original/2X/f/f04c62c3618dad7d1989f8631b8598efc82cbdbe.png)

> **[Ultra Prop Propellers - Ultralight Aircraft - Ultraprops.com](https://ultraprops.com/)**
>
> Ultralight Aircraft Propellers for Sale ! New Lower-Cost, Adjustable-Pitch, Solid Carbon Fiber Composite Propellers for Ultralight Experimental Aviation, Air Boating & More! They Make Excellent Small Engine Airboat Props for Mini-Airboats as well ​

So I’d say no way. Seems like a bad fit. Even the RPM limit for 54" is too low for our application.

From the HP/torque graph you are down a full 10HP at 2900.

 ![image](https://sonexpilots.org/uploads/default/original/2X/5/50428b6b91388525007b3ebfa6246cf93c1f5dcf.jpeg)

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**Author:** ![WesRagle](https://sonexpilots.org/user_avatar/sonexpilots.org/wesragle/32/1450_2.png) [@WesRagle](https://sonexpilots.org/u/WesRagle)\
**Post date:** [August 18, 2026, 8:13pm UTC](https://sonexpilots.org/t/considering-a-ultra-prop-ii-3-blade-66-diameter-for-aerovee-2-1-80hp/5905/3 "2026-08-18T20:13:48Z")

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Also, apparently these props are not intended to be used in direct drive applications.

As stated on their web site:

## **We ship WORLD-WIDE, the Original Ultra-Prop and the new Ultra-Prop II Solid Carbon Fiber Composite Propellers.** Use with belt or gear reduction-drive applications and electric **direct-drive.**

Wes