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Help! Prop Sizing Questions (PLEASE HELP!!)

moret

Well-known member
#22
Remember to also know the rules on flying. In the US, the pilot would need to be registered. I am guessing you will need to prove your design by flying it. Has anybody in your team did any flying?
 
#23
Why would the pilot need to be registered for a student competition? the plane will be over the .55lb limit, so it would need registration, but as far as I'm aware the pilot himself should be OK.

Is it just a rule of the competition or is there a cash reward for winning or something that pushes this into the commercial sector?
 

FDS

Elite member
#24
In many places the person has to be registered as an operator and it’s their number that goes on the plane. This is the case in the U.K.
The BMFA is running this competition so they will have sorted all that out, since they are like the AMA over here.
Only with more tea.
 

moret

Well-known member
#25
Why would the pilot need to be registered for a student competition? the plane will be over the .55lb limit, so it would need registration, but as far as I'm aware the pilot himself should be OK.

Is it just a rule of the competition or is there a cash reward for winning or something that pushes this into the commercial sector?
In the US a pilot must get a "registration" number from the FAA if the Plane is over .55 Lb. You put that same number on each of your planes.
Since the plane is over .55Lb, and they fly it, it will need a FAA number ( in US) on it. The number belongs to the plane's owner / pilot.

Or another way to say it, the pilot is registering himself to get a number? You give information about yourself not the plane.

Part 105, the pilot has a license and then they register each aircraft.
 
#26
For this competition BMFA has assigned already certified pilots to control our aircraft. We are required to compelete a series of checks and test to make sure our aircraft complies with the BMFA rules and regs as well as the CAA/EASA regulations. We as students (unfortunately for us) won't be allowed to pilot the aircraft.
 
#27
1) When calculating the thrust of a motor with a prop, how do I determine the RPM of the motor with a prop (adding load to a prop)?
2) Are there any calculations I can do to determine the ideal prop size without having to do any physical tests?
3) What is the most accurate dynamic thrust and static thrust equation I can use to calculate the thrust of my motor with a prop?
Just to quickly help you out here, get Ecalc for 2.49/month, search for your specific motor or a similar and type in the rest of your data like Battery, Prop, etc and hit calculate.
The results are really close to the Realworldmeasurements when on the bench, the measurements in the air are what the simulation says minus 10-15%.

You can also exceed the limit of the motor (like 10-15%) if you have to but in such case the efficiency goes down the drain and you have to have very good cooling.
 
#28
Hi Mathurd, im doing a project with the university this year too that has the same motor an battery to build a uav and im stuck with the same problems u were stuck with i was wondering if u can share how did u get around to sort this out
if u can send me an email maybe at amroalessandro@gmail.com
or whatsapp +447846732496
Thanks in advance