I want to build a fixed wing drone with the longest possible endurance possible. I'm thinking electric pusher(for aerial video) with solar panels and alternator(s) to charge the batteries. I have very little experience in building fixed wings but have extensive experience with multi and single rotors. And also with aerial video/photography. It can be over 55lbs, since im willing to get FAA experimental licencing for it. Im also planing on using an airport hangar so it should be large enough to be seen by small aircraft such as cessnas. The wingspan should also be around 30-40ft. And if we have to go to a gas motor, it would have to be an aviation motor being able to use AA or Jet-A fuel.
You would be better off using hydrogen as PEM fuel rather than lifting gas. Ion Tiger by NRL has more than enough endurance for your application.
The media stopped using aviation for traffic a long time ago. Traffic data is all electronic now. Between sensors in the road and crowd-sourcing, aerial traffic reporting went obsolete a decade ago.
You're going to use a $50,000 UAV at 2,000 feet above ground to take video of a little league game? lol.
Im not asking the industry to do this. Im asking you guys.
Hydrogen is off the table. There is absolutely no hydrogen on the airport. And as ive said before, Im hoping to stay at $10,000-$20,000 for the AIRFRAME, that cost is NOT including anything else that goes in it.
Im using this for my own enjoyment. But if some small local news agency or little league team wants to pay for my video they can.
So, you guys think it'd be best just to buy a glider airframe and build off of that?
On your budget the best option would be to purchase a well designed composite powered glider from the former East Block. Look closely at the Supra and related air frames http://www.kennedycomposites.com/suprapro.htm Up can purchase fiberglass or carbon composite versions. You can avoid a gearbox with a low KV brushless inrunner.
He's going to use the solar panels to power the electric motors so he can drive the alternator to charge the batteries silly!
A glider frame will never support all the avgas engines, electric motors, alternators, batteries, and solar panels he requires!
Read the damn OP people.
Matt (OP), Your project is suffering an extreme disconnect with reality. Unless you have a budget with several additional zeros, and some aerospace engineers on staff, what you want to do is not realistic.
Back to basics please, We all know that the concept of battery to drive motor to drive alternator (or generator) to charge the battery will NEVER work! you might add a little to the battery capacity by using the solar cells but that is offset against all the extra equipment you add to the aircraft
The various components all have an efficiency of less than 100% so every step loses power, it would be more efficient to simply use the solar cell to charge the battery. you cannot get energy for nothing. if you could then we would all have an over unity generator in the back garden... and no electricity bill each month!
it does not matter what voltage, current is used. Power in (W) = Power out (W) + losses (W),
you always put in more power than you get out, especially with rotating machines like motors and generators. with efficiency around 85% for the motor and the alternator to get 100watts out you put in 136Watts.
Have you checked this?
Under $5k with shipping, 15kg(33lbs) payload and 27 liters of fuel, that should probably give you a couple hours of flight.