Hi all,
What kind of thrust would you expect to get from an 1834cc VW?
What kind of thrust would you expect to get from an 1834cc VW?
So if I put a Spitfire prop on a VW, I get the same thrust? Cool! Same pitch, number of blades, and diameter of the prop, right?Thrust is determined by pitch, number of blades, and diameter of the prop, not by the horsepower.
At what airspeed and maximum prop diameter? The airspeed matters a lot.Hi all,
What kind of thrust would you expect to get from an 1834cc VW?
Maybe I should have also said "RPM" in that sentence but I did mention that you need an appropriate prop for the engine a bit later.So if I put a Spitfire prop on a VW, I get the same thrust? Cool! Same pitch, number of blades, and diameter of the prop, right?
I think you're bending the laws of physics with that statement.
Assumptions: SL, std day. 60 HP, 3400 RPM. Two-bladed wood prop with a pitch optimized for the given airspeed (so, the same prop won't produce all the numbers shown below). Prop diameter chosen to keep tip speeds below 880 FPM and reasonable camber ratios.
Airspeed.....Pitch....Diam............Est. Thrust
50 MPH........22.2".....59".................249 lbs
60 MPH .......24.4".....58"................231 lbs
70 MPH .......26.7".....57"................213 lbs
80 MPH........29.1".....56"................198 lbs
90 MPH........31.7".....55"................184 lbs
100 MPH.....34.6".....55"................172 lbs
110 MPH.....37.5".....54".................160 lbs
120 MPH.....40.5".....53".................150 lbs
130 MPH....43.7"......53".................141 lbs
I know that prop and engine combo has proven to be great for your SSSC. I'm guessing that the prop blades have quite a bit of camber to their airfoil if it gets you to 94 MPH with a 26" pitch. Sounds like it climbs great.Engine on the SSSC. 1835 cc, 60 HP, 3200 rpm at WOT @ 94 mph. Prop Culver 60" x 26" . Cruise at 2650/2700 rpm at 80 mph @ 3 GPH. ROC= 1200+ FPM.
I don't know about the pitch except its stamped 26" Could be different, I don't know. That climb of 1200/1250 fpm is at about 780 lbs.I know that prop and engine combo has proven to be great for your SSSC. I'm guessing that the prop blades have quite a bit of camber to their airfoil if it gets you to 94 MPH with a 26" pitch. Sounds like it climbs great.
If your aircraft has an expected climb/cruise speed of 20 mph, then secure it to a ground anchor with a load meter, apply full throttle and read the force indicated. What could be simpler?Hi all,
What kind of thrust would you expect to get from an 1834cc VW?
Running into the trees at the end of the runway while still in ground effect?If your aircraft has an expected climb/cruise speed of 20 mph, then secure it to a ground anchor with a load meter, apply full throttle and read the force indicated. What could be simpler?
Brian W
The thrust in cruise is same as the drag. So just shut off the engine and measure the airspeed and sink rate to calculate drag.What could be simpler?
CAFE set up switches to measure end float on the crank. They could tweak the throttle for zero thrust.The thrust in cruise is same as the drag. So just shut off the engine and measure the airspeed and sink rate to calculate drag.
If you want exact then remove the prop and tow it aloft. But who needs exact?