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  1. G

    Running aileron cables through struts

    Thanks for raising the additional issues. Every time I imagine anything that seems a little outside of the box in aviation, I always think to come here and ask for some second and third opinions from some seasoned vets. It never fails to educate and entertain!
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    Running aileron cables through struts

    I want to use struts on a high wing Part 103 ultralight for the extra HP then allowable under their formula. They could easily be mounted near stick and extend back to the wing. The thought occurred to me that this would be the most direct line out to the ailerons. Assuming the strut was up to...
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    Double post. Can't delete it.
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    Maybe simpler is better. How about a system that cuts back power to my hypothetical 25kw whenever speed is over 54kts.This would allow for a HUGE climb rate. 1200fpm would be awesome in an ultralight powered-glider! And that extra power could then also be used for stall recovery, go arounds...
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    The FAA has officially stated this would be inadequate. Basically, if has to be a system that cannot be overridden in flight.
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    That's kind of what I was thinking with the button. Maybe a "trigger" on the grip could work. I like the idea of going off of stick position. I need to think it through, but that could make sense. In a sense it's even "cheatier" than I was thinking, but it also would be fairly simple to implement.
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    No, there's really not anything strictly "e" about this, except that in an ICE engine, the work to implement it reliably would be akin to creating a fadec system from scratch, but for an e-plane, it'd be as simple as connecting your speed controller to a computer and adjusting parameters. You've...
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    But the pilot could also enter a dive, level off, and exceed 55kts in level flight. How is exiting a climb different from exiting a dive? Except for the way that breaks the laws of physics and "but, it's not supposed to work that way". Clearly, the requirement means it must be able to sustain...
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    E-Turbo for an E-UL (a legal 100mph Part 103 UL is possible!)

    ...so long as it only reaches that speed while climbing and gets the power chopped back when in dead-level flight). This is referencing an ultralight glider. In a nutshell, any powered UL glider is an "ultralight" and gets lumped in with the 254lb folks). I spent some time rereading Part 103...
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    An I-beam for a tail?

    What do you think of cluttonfred's 4th image? An outside box beam? I'd never heard that term before, but that's exactly what I was thinking of. I was figuring a foam core of between 1/4" and 4" depending on what was needed for torsional loads. I was only calling it an I-beam for lack of a...
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    An I-beam for a tail?

    You're flat out right. I was thinking of an I beam with a foam core between shear webs, and the caps would be joined, but that can basically be viewed as a box beam. The right-most picture is the closest to what I was thinking of. One of the ideas is to use the "cove" in the outside box beam to...
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    An I-beam for a tail?

    In this use case, a little weight could be sacrificed for simplicity of construction, given that speeds are not a primary goal. A foam core within the shear web could help provide some torsional stiffness.
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    An I-beam for a tail?

    Some material testing may be required here, but follow along with me on the basics. Primary gliders just have a truss with two dimensional "spar caps" and some reinforcing at the joints. These tails tend to be rather short, which I assume reduces twisting forces. They may also use some wire...
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    Eppler Airfoils

    Great question. And I could be very well proven mistaken, but here is my thinking. 1. At ultralight speeds (even with there being no speed limit for Part 103 gliders) there may not be a huge aerodynamic advantage to using any airfoil at all as opposed to even a flat plane. 2. Weight is a very...
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    Eppler Airfoils

    The E472 has max thickness at 17.5% of chord. Max thickness is 12.1%. It is a rather unusual airfoil that's designed for aerobatic aircraft, but I am considering repurposing it for an ultralight, due to the aforementioned benefits... Because, realistically, a flat slab of plywood with some...
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    Eppler Airfoils

    Is there a rhyme or reason to Eppler's naming conventions? I'm hoping to find a 10% thickness version of his E472 for an ultralight glider tail. I want that one for the reason of simplicity of construction (relatively straight aft of max thickness) and having a rather "forward" max thickness to...
  17. G

    Could sports foam be used for shock absorption?

    Yeah. I did some maths. It looks like that's in the ballpark of what I was thinking of. Very cool. Thanks!
  18. G

    Could sports foam be used for shock absorption?

    I'm speaking about ultralight aircraft here, just to be clear. Rubber donuts, springs, shock cords, and spring steel gear all suffer the same problem - fast rebound. The solution is air oleo struts, but those are heavy. Would it be possible to engineer (or aquire) an off-the-shelf memory foam...
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    Single-seat ultralight puddlejumper: the "Carbonmax"

    I am working on an ultralight glider with a similar approach to things. One thing to consider is the molds. If you are looking to sell 100 planes a year, molds make sense. But if you are looking to build one plane easily, molds do not. I am currently working on using flashing (roofing sheet...
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    Cheap ultralight wing coverings

    It's not what you are asking for, but may be worth considering - I am looking at Oratex. It's like $40/yard, but if it keeps a homebuilder from having to buy a spray gun, compressor, etc., and takes a multi-step process to a single step, it may be worth it for something intended for one-off...
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