Hi,
I am currently in an University competition representing my school and my team is tasked with building an RC plane which will be designed to undergo several challenging missions. Most of us are total newbies when it comes to RC planes and I am sure all of you guys are really experienced so I came here to look for some help.
As a mechanical engineering student, I know a decent amount about the construction of the plane and have help build a few over the years. My main issue currently is with the propulsion, and this is where I figured you guys could help me out. I need to figure out what kind of batteries, motor, esc and fuse to use.
Fuse:
I am limited to use a 15 amp fuse but this can be a slow blow type. In fact I am trying to get as much over that 15 limit to give me an edge over the competition. Do you guys have any recommendation for a 15 amp rated fuse that can get 17, 18, or even 19 amp averages over 5 minutes without blowing? (
yes, competition rules require a fuse because it is used as a quick way to make sure everyone is following the power requirements without taking the plane apart and for safety reasons. The fuse is the last thing to add before takeoff and first thing to remove after landing.)
Batteries:
They only need to last 4-5 minutes. This includes take off, flight, and landing. But my main constraint is 15 amp current. Unfortunately, I am limited to NiHM and cannot use LIPO ones :/ Do you guys have any advice on how I can determine what batteries would be best for the application?
Motor:
I am expecting to buy something between 300 and 500 watts just based on my power constraint. I am allowed to spend up to $200 for the motor. Once I decide on the batteries and motor I will look at props. For my 2 missions in the competition I will need a prop to bring my plane up to full speed and then carry a heavy payload. For the speed mission I am guessing something around a 12x12 will do the trick and for the payload mission, I was going to try a few in the 13x10 range. I could use any advice you guys have for me on how to select the right motor/prop combination.
Speed controller:
In this category I really don’t know where to begin, I was just going to follow the recommendations of a hobby story sales person.
I am very lost on the whole electrical aspect of this project and I appreciate any help you guys can give me.
(official rules:
http://www.aiaadbf.org/2014_files/2014_rules_31Oct.html)
(I have a similar thread on RC Discuss going:
http://www.rcdiscuss.com/showthread....-use-some-help)
(supplementary RC Universe threads:
http://www.rcuniverse.com/forum/elec...challenge.html and
http://www.rcuniverse.com/forum/elec...my-set-up.html)
Updates:
I received a huge help from the forums and have a strong understanding of the electrical system. Now my team has to order the parts and optimize through testing once everything arrives. For the first test flights we are "cheating" by using lipo batteries until we have the propulsion system is optimized.
The team has built the first prototype. The plane is very crude and heavy because we used old parts and cheap material such as cardboard and duct tape. We can get away with this design because the final plane is expected to carry a heavy payload. Future prototypes (we should have 1-2 more by February) will be much better designed.
Team had first test flight. We discovered the plane had some longitudinal stability issues.
Team had second test flight. Longitudinal stability issues resolved but we discovered lateral stability issues.
Current task: fix lateral stability and get more test flights in.