ckurz7000
09-06-2010, 09:30 PM
I've been sitting on those numbers for a while because a lot has been going on in my life lately (got married to the most wonderful woman in the world, rebuilt an old house and moved in). These test results are the average of two data runs. Of course I would normally add at least a third set of data but that would delay the posting even more, and I don't expect a significant change in numbers.
The data runs were done at a take-off mass of 400 kg and a density altitude of 3000 feet. For those not into interpreting graphs, here is the gist of it:
Most economical cruise (something like 55% power setting) is at a pitch of 300 and 4300 rpm with a fuel flow of 14,5 liters/h and 125 km/h of CAS. This gives you an endurance of 4:30 hours and a range of 560 km (while still having the required 30 minutes of reserve in the tank).
A fast cruise (akin to a 75% power setting) would be at a pitch of 500 and 5000 rpm with a fuel flow of 20 liters/h and 157 km/h airspeed. The range at this setting is down to 500 km.
Just a reminder of how I determine the prop pitch setting: I choose 5000 rpm at max fine pitch and straight and level as a reference point. Adjusting the pitch coarser from there, I note the drop in rpm and use that as a pitch indication. So a pitch of 500 would be the pitch that gives you an rpm drop of 500 from the reference point.
Here's the data plots as pdf:
73656
73657
73658
Greetings, -- Chris.
The data runs were done at a take-off mass of 400 kg and a density altitude of 3000 feet. For those not into interpreting graphs, here is the gist of it:
Most economical cruise (something like 55% power setting) is at a pitch of 300 and 4300 rpm with a fuel flow of 14,5 liters/h and 125 km/h of CAS. This gives you an endurance of 4:30 hours and a range of 560 km (while still having the required 30 minutes of reserve in the tank).
A fast cruise (akin to a 75% power setting) would be at a pitch of 500 and 5000 rpm with a fuel flow of 20 liters/h and 157 km/h airspeed. The range at this setting is down to 500 km.
Just a reminder of how I determine the prop pitch setting: I choose 5000 rpm at max fine pitch and straight and level as a reference point. Adjusting the pitch coarser from there, I note the drop in rpm and use that as a pitch indication. So a pitch of 500 would be the pitch that gives you an rpm drop of 500 from the reference point.
Here's the data plots as pdf:
73656
73657
73658
Greetings, -- Chris.