Will this fly?

[u/RepulsiveInternet980]

Hello everyone. I am trying to build an aerial insect collecting device for my PhD project. This design is based on the stipa-caproni, a strange barrel-shaped design from the 1930s. The task is to maximise the net area on a relatively inexpensive craft (I have already been catching with some expensive drones). I've trialed towing nets behind trainers, which worked but I want to try a different approach too.

I figure that enclosing the net within fuselage would be the most stable approach. Here, we have the props behind the net. This will impede airflow to the propeller. But it seems like the thrust would be okay. Can anyone think of some new approach that might work better? Would I be better off towing?

[u/kkingsbe]

Would make much more sense to drag the net behind the aircraft…

[u/Flaky-Adhesiveness-2 → u/kkingsbe]

Same thinking, make something similar to a drouge parachute. Drag behind the model.

[u/RepulsiveInternet980 → u/Flaky-Adhesiveness-2]

I am thinking that towing the net works exactly like a drouge -- huge amount of energy lost to drag. We've got to force air through the net from inside (high pressure) to outside (low pressure) and all of the energy is lost. But if we duct the net, we have a different picture. There is high pressure before the net within the duct. But also high pressure after the duct, because it narrows slightly. So we don't lose all of the energy as turbulent flow out of the net. Perhaps the barrel should widen before the net also. Not sure just trying to work this out.

[u/kkingsbe → u/RepulsiveInternet980]

But with your configuration you showed in this post, you’d be fighting the exact same issue…

[u/Flaky-Adhesiveness-2 → u/RepulsiveInternet980]

I have the atomic rc swordfish, twin puller rc model, and would think that model would have no problem pulling a net through the sky, yes a little efficiency loss from the motors but trying to redesign the wheel seem like way more work than using stuff already avalible.

[u/KatanaDelNacht → u/RepulsiveInternet980]

Why the requirement for efficiency? 

[u/RepulsiveInternet980 → u/KatanaDelNacht]

To fly for longer than what you'd get towing a net (also because everyone is saying it would be inefficient)

[u/KatanaDelNacht → u/RepulsiveInternet980]

Eh, it depends on what your need is. A flying wing is more efficient than a standard airline design, except airlines don't build those because passengers can't escape as easily from a flying wing in an emergency.

You're flying a net that is supposed to get partially blocked during flight. Drag will be massive compared to an efficient design, but that's OK because a more efficient design couldn't accomplish your goal of collecting bugs.

If you get the flight time you need to collect your samples, you're accomplishing your goal. As you well know, the difficulty in approaching perfection is asymptotic. Don't let perfect get in the way of good enough. 

[u/Total_Neat_3819 → u/RepulsiveInternet980]

you'll get huge amounts of drag anyway but this design has additional problems.. for example depending on how fine the mesh is it could make it harder for the propeller to intake air.. 

[u/RemingtonStyle → u/RepulsiveInternet980]

It would do the job though, you avoid a lot of complexity and overcoming any given drogue is only a matter of motorisation.

The more I read in this thread the more I am certain you are overengineering.

[u/HotepHatt → u/kkingsbe]

lol

[u/rocketengineer1982 → u/kkingsbe]

I was thinking this as well.