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Electric Aircraft for Engineering Senior Design Project

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tgcastleman

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May 9, 2014
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Dallas, TX
I am a senior mechanical engineering student at Lamar University (Beaumont, TX). For senior design, I am working with a team of 3 other students towards designing a single-seat, multi-engine homebuilt experimental electric aircraft. I would prefer not to post too many details here on the internet right now, but we are seeking experienced advice on general aircraft design and electric propulsion for aircraft.

So far, our initial (very first) sizing calculations put the aircraft somewhat in this range:

Weight: 400-700 lbs empty (with 100-200 lb battery)
Power: 30-55 hp
Cruise: 70-110 kts
Composite construction (foam & fiberglass)

That is all I would like to say about it specifically right now. If you are interested in being involved, please send me a message on this website with a brief description of your applicable experience/education and interest in participation.

I would like to hear the community's opinion on our current top choice for motors. We are looking at using four of the following motors.

https://www.getfpv.com/lumenier-lu15ii-100kv-professional-motor.html

Also, please feel free to post about specific possible sources of funding for this kind of project.

Thank you guys. I will post more information as the project progresses.
 

Pops

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Why electric ? How about steam ?
 

tgcastleman

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I was taught respect for elders, so I won't engage you, Pops. But thank you for your meaningful response....

If I had a nickel for every time someone told me batteries are too heavy to be practical for aircraft, I could pay for the entire project myself. I would answer your question "Why electric" but your follow up question of "How about steam?" makes me think you're being sarcastic.
 

Voidhawk9

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You've specified the type of engine, number of seats, and construction materials. But what is the mission?
 

Hephaestus

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Follow the Trainwreck called the raptor for a good understanding of why you don't develop both an airframe and powerplant as a single project.

Take a known design tweak it electrify it. Let's not kill off thesis students - the ROI sucks.
 

Pops

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I was taught respect for elders, so I won't engage you, Pops. But thank you for your meaningful response....

If I had a nickel for every time someone told me batteries are too heavy to be practical for aircraft, I could pay for the entire project myself. I would answer your question "Why electric" but your follow up question of "How about steam?" makes me think you're being sarcastic.
Not sarcastic. Like electric, its been done, but not perfected. Water can be recycled and maybe Propane,etc,etc, to flash fire a boiler. Engineers everywhere are trying to do what you want to do, you will just be another attempt by multiple people all over the world trying to do the same thing. Work on something different and not be just one of the many. I know its not PC in today's socialist world where everyone is to be the same, but if being PC is in your decision there is little chance of meeting your goals. Think outside of the box and not invent another version of the wheel.
Now, IF you can come up with some HUGE break thru in Battery Technology that is also being worked on all over the world you can write your ticket. This is where the problem is located.

https://flashsteam.com/
 
Last edited:

BJC

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Follow the Trainwreck called the raptor for a good understanding of why you don't develop both an airframe and powerplant as a single project.

Take a known design tweak it electrify it. Let's not kill off thesis students - the ROI sucks.
A “Senior design project” is far from an actual design. It is more of an exercise to see if the students have a fundamental grasp of basic aerodynamics, structures, and stability and control. Very worthwhile, but far, far removed from detailed design.


BJC
 

Hephaestus

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A “Senior design project” is far from an actual design. It is more of an exercise to see if the students have a fundamental grasp of basic aerodynamics, structures, and stability and control. Very worthwhile, but far, far removed from detailed design.
Maybe I'm nuts but just the tweaks to adjust for loads and construction methods - maybe some aero upgrades. Sounds like a good thesis start...

Ground up design of aircraft and power system... That's a massive project.
 

pictsidhe

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85% motor efficiency at part throttle seems low to me. I'd go for higher efficiency motors. Likely geared for low weight. Multicopter motors, especially big ones, are optimised for rapid speed changes, not high efficiency.
 

Pops

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Maybe I'm nuts but just the tweaks to adjust for loads and construction methods - maybe some aero upgrades. Sounds like a good thesis start...

Ground up design of aircraft and power system... That's a massive project.
That is an understatement.
 

Aerowerx

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Keep in mind that they are to design a multi-engine electric aircraft that weighs 400-700 pounds.

Most all of the electrophiles here on HBA seem fixated on developing an electric Part 103 ultralight. And they never seem to get very far off the ground (yes, that was a pun!).

By going for an EAB class, they are giving themselves far more degrees of freedom to actually get it to work.
 

Hephaestus

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Wait hang-on... I was just talking about this the other day ;)
122.png

Popular mechanics and scaled did the rough out.

Definitely needs to be built, open source the drawings calculations and design when complete!
 

BBerson

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85% motor efficiency at part throttle seems low to me. I'd go for higher efficiency motors. Likely geared for low weight. Multicopter motors, especially big ones, are optimised for rapid speed changes, not high efficiency.
That chart doesn't list motor efficiency. It does show how much worse the thrust per watt is as power is increased.
 

BoKu

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Keep in mind that they are to design a multi-engine electric aircraft...
That actually makes a lot of sense for a low-budget development project. There are a lot more 10kw motors commercially available than 40kw motors, and they're already optimized for props. Various inescapable redundancies means that they're leaving a non-trivial amount of performance on the table, but might be a fair tradeoff for not having to have a custom motor built.

As for the mass, well, that's all about the mission. The HP-24F is on track to have an empty weight of around 550 lbs including the motor and enough battery capacity for almost an hour at cruise, so what they're proposing is definitely possible.
 

Kyle Boatright

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I am a senior mechanical engineering student at Lamar University (Beaumont, TX). For senior design, I am working with a team of 3 other students towards designing a single-seat, multi-engine homebuilt experimental electric aircraft. I would prefer not to post too many details here on the internet right now, but we are seeking experienced advice on general aircraft design and electric propulsion for aircraft.

So far, our initial (very first) sizing calculations put the aircraft somewhat in this range:

Weight: 400-700 lbs empty (with 100-200 lb battery)
Power: 30-55 hp
Cruise: 70-110 kts
Composite construction (foam & fiberglass)

That is all I would like to say about it specifically right now. If you are interested in being involved, please send me a message on this website with a brief description of your applicable experience/education and interest in participation.

I would like to hear the community's opinion on our current top choice for motors. We are looking at using four of the following motors.

https://www.getfpv.com/lumenier-lu15ii-100kv-professional-motor.html

Also, please feel free to post about specific possible sources of funding for this kind of project.

Thank you guys. I will post more information as the project progresses.
 

Dana

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As others have said, what is the mission? The numbers you've given cover a wide range, from near ultralight to quick and efficient on modest power (think Davis DA-11). The balance of speed/range/payload/runway length will dictate where you fall in those ranges (or if it's even possible with electric).
 
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