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RC Photo Plane: basic design considerations


The goal: to have a controllable, slow flying RC
(radio controlled) platform carrying a digital
still camera into the air for the least possible
money.

The Camera: Light weight (< 8 oz?) Cheap (used
on Ebay?) High pixel count (resolution) to allow
cropping the image.

That’s specific enough to get us started --
we’ll come back to this topic later. For now,
suffice to say that, as a friend of mine puts
it, “Fast, cheap, high quality -- choose any
two.” Substitute “light weight” for “fast” and
you’ll get the idea with cameras.


The Plane: Ok, so we need a slow flying vehicle
with lots of weight (cargo) carrying capacity.
Turning to full size planes for guidance, the
Swordfish, a WWll torpedo biplane comes readily
to mind.

It had lots of carrying capacity relative to its
size (it weighed about 4,000 lbs and could fly
at 7,500 lbs fully loaded), and it flew slowly.
Check out photo here.

Only one problem, in terms of basing our camera
platform on this design: the spinning prop would
be in the way of a nose-mounted camera. And we
do want a nose-mounted camera for the
versatility of shooting from any angle between
dead ahead (horizontal) to straight down
(vertical) while in level flight.


Get thee behind me, propeller!

So let’s put the propeller in back, out of the way of our
nose-mounted camera. Turning again to the web
(Google: pusher biplane) we do find examples of
this configuration out there. [Example]

This might be the way to go -- not exact scale,
but at least for inspiration / a starting point
-- if it weren’t for the concern that a pusher
design would seem to need a good amount of
forward speed to get the lifting surfaces
working (no prop wash), so needing a long
takeoff run which would eat battery power,
reducing flight time. (The plan is to go
electric, since gas offers too many possible
issues with oil and vibration to go well with a
camera.)


How about a twin engine biplane?
Now this could work -- twin motors offer more power, as well as putting those spinning props out there on the
wings, well out of our way. And yes, a quick
search shows examples of full-sized twin
biplanes, so apparently there’s no fundamental
problem with this general design. [Example] Note
the empty, un-obstructed nose, exactly what we
want for a camera.

We’ll mark this as a “maybe / possible” way to
go.


What about a RC helicopter?

Upsides:
Very maneuverable
Can hover in one place for repeat shots
Said to be better in wind than fixed-wing craft.

Downsides:
Expensive to buy as kit or RTF (ready to fly)
Complex to home-brew from scratch
Steep -- and potentially costly -- pilot learning curve Vibration from so many moving parts


Or maybe a multi-rotor flying platform...? [Example]
These are intriguing, sharing the
advantages of a helicopter, but they also have
the same downsides. Added to which, they won't
autorotate -- instead, they crash -- in the
event of a power failure. And while
mechanically simpler than copters, the homebuilt
examples I’ve seen on the web all seem to
require a lot of onboard chip programming to
make them work.

One possible way around this hurdle might be to
use the built-in programming capabilities of a
good transmitter. I’ve never seen an example of
this, and I’m not sure it can be done that way.
For now, that route seems like an expensive bet
with very weak odds.


Conclusion Based on our little set of
aeronautical thought experiments, a twin engine
(twin electric motor) biplane looks like a good
general direction to start.

On that premise, the next things to consider are:
plane size and construction materials; radio gear;
power system; camera mount and control.

[Link to next article]

 

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