prop-thrust.htm - from American Airboat Corporation - Manufacturers of the World's Finest Airboats

 

 Not every airboat builder is able to get the maximum performance out of their engine prop combinations. 
For starters, you need a dynamometer for the engine and a thrust meter for the engine prop combination . 
What isn't shown here is how the pitch is modified and re-tested to extract the maximum from the engine - prop combination. 
  Propeller Options

Power output is directly related to displacement and can be increased with performance options.  Generally speaking 
- The three blade prop requires a 454 , 496  , 502 or 572
   and a reduction drive 
- The four blade prop requires a 502 or 572
   and a reduction drive 

Pitch adjustment is for fine tuning.  To change the pitch, the hub must be unbolted and the blade twisted.

 Wide blade adjustable pitch composite - right hand or left hand rotation 

No. blades Diameter Required H.P. List Price Thrust @ 2800
2  Automotive 72 inches 200 h.p. $Call 520 lbs. est.
3 78 inches 380 h.p. $Call 580 lbs.
4 80 inches 450 h.p. $Call 600 lbs.
6 82 inches 600 h.p. $Call .
2  Aircraft  70 inches 160 h.p. $Call 450 lbs.

The sonic barrier is <700 mph under hot humid sea level conditions - Tip speed breaks the sound barrier at 3000 rpm. Prop noise results largely from high tip speed. The design goal is to achieve high thrust at below 2400 rpm which reduces stress on components, fuel burn, and noise.

Propeller Thrust Comparison -

RPM Levels Pounds of  Thrust Generated
Engine Prop PSP 4B* PSP 3B AP 78-42 Sens 78-42 Sens 78-42 FLA 78-42
1000 
1500 
2000 
2500 
3000 
3500 
4000 
4200 
4400 
4600		 500 
750 
1000 
1250 
1500 
1750 
2000 
2100 
2200 
2300		 60 
140 
250 
400 
600 
840 
1110		 140 
220 
300 
420 
580 
820 
1000 
1200		 0 
80 
160 
290 
560 
780 
1040 
1160		 40 
100 
180 
300 
510 
740 
960 
1130		 30 
90 
160 
280 
450 
590 
760 
873 
987 
1100		 30 
100 
200 
340 
510 
680 
950 
1050 
1160

*PSP 4B - PowerShift Propeller  4 blade
Data Source - Thrust Comparison Test, Orlando Airport, Friday, Mar. 8th 1996, reported in US Airboat magazine

Link Page     More Prop Cost Data     Engine Specs
Specification Sheet  (printable 3 page listing)  Quick Specs
Side by Side seating:
Latest 20 x 8 ft. design - 502 cu. in. V-8 - 500+ H.P. 4 blade composite prop.		 Contact:  Stan Floyd 
Let us send you a quote on the boat of your dreams.

Updated April 2007