Cessna 188 Conversion
Davis Aviation offers engine upgrades available for Cessna 188 Ag Wagon and Ag Truck aircraft equipped with the IO-520 D engine. (Ag Pickup or Ag Husky not included). Our STC removes the IO-520 D and replaces it with the 300 HP continuous IO-550 D. This powerful engine is installed with your choice of various propeller options.
Formerly known worldwide as the “Bonaire 550”, this conversion provides phenomenal performance with shorter takeoff roll, increased rate of climb, and faster cruise speeds. Basically, we picked up where Cessna left off when manufacturing stopped in the late 1980’s. Most of the older propellers have become obsolete and require replacement. The higher horsepower engine installed with the newer design propeller change, makes a cost effective difference for your Cessna 188 at minimal expense.
Propeller options with the 550 include the the Hartzell Paddle Blade 82 inch 3 blade, 80 inch Hartzell Top Prop 3 blade, as well as an 86 inch McCauley 2 blade (threadless hub). Other prop only STC’s can be combined with our IO-550 to offer more propeller options for you. If you have upgraded your propeller already, generally the model you have installed is compatible with our IO-550 STC. Give us the model number of the existing propeller upgrade and we can determine compatibility.
Davis Aviation provides a propeller kit package for your convenience including new propeller, spinner assembly, tachometer, MP/FF gauge, silicone baffling, shock mounts, standard hoses firewall forward (firesleeving included if requested), miscellaneous hardware, placards and STC paperwork. If you have a compatible propeller, we can do a partial kit package without the propeller and spinner.
If you are not ready for an engine but need a propeller now, we can offer propeller only option that is compatible with the 550 engine at a later time (in most cases). The remainder of the IO-550 upgrade can be purchased, as you approach TBO, to complete the performance modification. Basically making the conversion in installments.
IO-550 Conversion Improvements
- 400 inch lbs more torque over the IO-520 engine/15% More Horsepower at Cruise.
- Quieter operation: the noise level at 2700 RPM is greatly reduced with the 80 or 82 inch 3 blade propellers or the 86 inch 2 blade.
- 10-15 MPH additional swath speed improvement depending on propeller choice.
- 10%-20% better rate of climb at gross Continuous 300HP without limitations.
- Short field take-off 10%-20% less at full gross weight.
- Cost difference is normally offset by the added value to the plane.
