Ultra-Prop 1 Propeller Recommendations | ||||
---|---|---|---|---|
Engine | HP | Reduction Ratio | Prop Diameter | Pitch |
R503 DC | 52 | 2.58:1 | 59" | 15° or 16° |
R503 SC | 48 | 2.58:1 | 59" | 14° or 15° |
R447 | 40 | 2.58:1 | 59" | 13° or 14° |
R477 | 40 | 2.58:1 | 59" | 16° |
R377 | 35 | 2.58:1 | 59" | 13° or 14° |
R377 | 35 | 2.58:1 | 59" | 11° |
R277 | 28 | 2.58:1 | 59" | 10° or 11° |
Honda/B&S | 13 | Direct Drive | 36" | 13° |
Honda/B&S | 20 | Direct Drive | 42" | 15° or 16° |
Honda/B&S | 20 | Direct Drive | 42" | 14° |
Hirth F33 | 28 | 2.5:1 | 59" | 10° or 11° |
Hirth F33 | 28 | 2.5:1 | 52" | 17° or 18° |
Hirth F33 | 28 | 2.5:1 | 59" | 13° or 14° |
Hirth F33 | 28 | 2.5:1 | 55" | 17° or 18° |
MZ 34 | 27-32 | 2.34:1 | 57" | 10° or 11° |
MZ 34 | 27-32 | 2.34:1 | 52" | 15° or 16° |
MZ 34 | 27-32 | 2.34:1 | 49" | 17° or 18° |
MZ 34 | 27-32 | 2.34:1 | 59" | 10° or 11° |
MZ 34 | 27-32 | 2.34:1 | 57" | 13° or 14° |
MZ 34 | 27-32 | 2.34:1 | 52" | 17° or 18° |
*Increase pitch by one degree for every one inch decrease in diameter.
**A change in pitch of one degree is worth about 200-300 change in engine RPM. Increasing pitch will decrease RPM. Decreasing pitch will increase RPM.
***Other lower reduction ratios are available.
NOTE: If a loud “buzzing” noise is noted at high RPM with high-pitch blocks, it is because the tips are stalling. Do not operate the propeller in this range. Either a lower pitch or smaller dia. prop must be used.
Tests have shown that at and below 52-in. dia., no blade tip stalling will occur with 18-degree pitch blocks below the rated 3100 RPM.
Between 52″ dia. and the full 59″ dia., the approximate tip stalling RPM or onset of buzzing is shown in the table below for various pitches.