Page 2 of 2

Posted: Sun Jul 03, 2011 1:08 pm
by saefroch
I voted for the plane, if you're wondering. In my opinion, if it's really that tail-heavy it'd be hard to do much about it in flight.

Posted: Sun Jul 03, 2011 2:00 pm
by jackssmirkingrevenge
saefroch wrote:I voted for the plane, if you're wondering.
Isn't it the pilot's job to correctly balance the plane before attempting a test flight?

Posted: Sun Jul 03, 2011 2:04 pm
by saefroch
Ah yes but at that point he isn't the pilot, is he? I only considered him the "pilot" during the duration of the flight. But it was a design flaw, nonetheless.

Posted: Sun Jul 03, 2011 3:05 pm
by velocity3x
saefroch wrote:Ah yes but at that point he isn't the pilot, is he? I only considered him the "pilot" during the duration of the flight.
FAA considers the preflight (including weight and balance) inspection to be the pilots responsibility.

Posted: Sun Jul 03, 2011 3:20 pm
by Demon
I underestimated the CG location. It was spot on the CL, while it is required (for those who start) to make the plane very nose heavy. It was unstable, but by my fault.

Posted: Sun Jul 03, 2011 3:55 pm
by jrrdw
Being as how the entire vehicle is a wing I can see why it would be a judgement call on the CG. If it where my build I would have tried to get it in the center as close as possible. That would give you a dead center stick.

Posted: Sun Jul 03, 2011 9:09 pm
by saefroch
velocity3x wrote:
saefroch wrote:Ah yes but at that point he isn't the pilot, is he? I only considered him the "pilot" during the duration of the flight.
FAA considers the preflight (including weight and balance) inspection to be the pilots responsibility.
I stand corrected. Pilot's fault.

Feel better? :P

Posted: Mon Jul 04, 2011 12:47 am
by velocity3x
saefroch wrote: I stand corrected. Pilot's fault.
Feel better? :P
I really don't care so, I don't feel anything about it. :roll:

Posted: Mon Jul 04, 2011 3:20 am
by Technician1002
In that design, much like flying parachutes, consideration must be given for the fact the prop is not inline with the CG, but it way below it. If the wing has high drag, the thrust will impart a strong nose up rotation to the craft at slow speeds (near stall) that will make for an extreme unstable condition leading onto a positive feedback loop into a stall condition.

Part of the solution is to add considerable down thrust to the engine to reduce the thrust induced nose pitch up.

This may be why it launched OK then failed. It got sufficient ground speed to fly, The climb out was too steep resulting in nearing a stall condition, the nose up tendancy rapidly put the craft into a stall.

The three errors were two design related including CG and down thrust issues and one pilot error of the climb angle and loss of speed resulting in the stall.

Yes, I do some RC too.

Due to the pilot responsibilites, this is mostly a pilot error.

The flying field seems to be improper for a shakedown flight. Too may obstructions and the risk to the public was an issue. Another 2 votes for Pilot error. Is there a local flying field that is open for RC and not boxed in by apartment blocks and trees?