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Low-hanging stability weight for FPV

Dane

Junior Member
#1
Low Fuselage for FPV Stability

Notice: Excuse my crudeness, I am not very technical. I apologize in advance if you read it and please don't laugh at me! Just brainstorming stability solutions :)

Notice 2: I've pretty much scrapped the idea of the secondary weight. But I still like the idea of the lowered fuselage.

The Idea: To lower the fuselage further below the wings, to improve stability, create a nice platform and view for FPV rig. The wings and tail would be attached to the main fuselage with carbon fiber rods, or another material, that wouldn't increase wind-resistance from other directions (Like a crosswind)

Excuse my bad drawings, wacom tablet is broken.

Maybe this will make more sense? Very rough idea.




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Spoiler!
 

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earthsciteach

Moderator
Moderator
#2
It is not difficult to make an airplane inherently stable. Any decent trainer will be inherently stable, accomplishing this with wing dihedral. Your diagram above includes dihedral. This wing configuration is inherently stable because when the aircraft banks to one side, the low side wing is more parallel to the ground than the high wing as can be seen in your third diagram. In this configuration, the low wing is producing more lift than the high wing and therefore, without aileron or rudder input, will cause the airplane to return to a level roll position. Your idea of the weight swinging toward the low side wing would counter this natural stability.

Your idea is looking at stability from a roll standpoint only. An airplane has two more axes to consider - pitch and yaw. So, using the idea of a stabilizing weight, it would have to be controlled through all three of those axes, compounding complexities. Also, this adds weight to the airplane requiring more power, which, in turn adds more weight to the aircraft.

I'm not saying that your idea doesn't have validity. I've played around with the idea of a shifting mass in a rocket to control fins for stabilization. It always gets stuck somewhere in my brain and I never have quite gotten the idea worked out.

With the availability of flight stabilizing gyros at low cost, I'd go with those over a mechanical system. It would not be difficult to add gyros to a camera gimbal system to really remove the "bouncing around." due to wind, vibrations, etc.

Just my thoughts. Don't take them as discouragement!
 

Dane

Junior Member
#3
Just my thoughts. Don't take them as discouragement!
Not at all! In fact I scrapped the idea of moving the weight soon after I posted it! I do however still like the idea of a lowered fuselage, it could make for some interesting looking planes.

The real application for this would be high altitude FPV, or any type of fpv that is subject to persistent or unpredictable winds. I think that if some kind of solution like this could be found to reduce movement, then the addition of a gyro on TOP of that would mean far less micro-maneuvers the gyro would have to perform.

My drawings are terrible of course but the fuselage would be fixed to the wings and tail via minimal surface area. Like carbon fiber rods. This would allow you to lower the fuselage weight downwards, without creating counter-productive wind resistance.

Correct me if I am wrong please!

EDIT: Dropped an edit into my original post. Hopefully we can talk on the lowered fuselage subject now without having to make a new thread! Thanks again for your response.

EDIT 2: Bear with me a bit, gonna change the original post around.
 
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