GP Ultimate 1.60 Crash

[Matt Merciez]

Just finished building a GP Ultimate 1.60. Weight was 15 lbs 13 ounces which was consistent with those running a DA-50 for power.

First two flights showed a plane which just did not track well and had very severe pitch coupling. The plane would not glide at all on landings, would actually fall like a brick.

The third and final flight (I mean final flight) was recorded on a video camera. Cause of crash was pretty simple, pilot error. No mechanical or electrical failurers, I was the only person flying at the field.

Here is the video http://video.google.com/videoplay?do...timate&pl=true

[SleepyC]

DAMN dude.
Sorry to see that.
Seems like the plane flew ok untill the end?
But you say you had to fight it?
Do you think it was the weight of the DA that made it heavy?
(meaning that the plane needs a LIGHT motor, no disrespect to the weight of a DA)
Perhaps this plane is a good canidate for the new BME 55 when its out?

Sorry for your loss..... (taps playing)

[Matt Merciez]

It is really hard to say what was wrong. I had not flown a biplane before, so it is hard to say if the plane was really an ill handling plane or just my lack of experience.

I would guess based on the video that the right wing stalled inducing the spin. The right wing was the inside wing on the turn so it had less airflow. I was also inputing right rudder at the time to align the plane for landing. I really did not believe the planes airspeed was anything close to a stall speed when the stall occured.

A fellow flyier at the field commented that the incendence could be off for the top wing (after the second flight). He then performed a crude visual, and speculated that the top wing could indeed have a positive incendence which would have resulted in the poor tracking. Unfortunately, the plane never made it home in one piece to check the incidence. It was also something I did not check before flying. If the top wing incidence was off enough to affect the lift capabiltiy, then I could easily see how the stall occured.

Regardless of the problem, it was still pilot error. I knew based on the two earlier landings that the plane did not like the glide, i.e. poor wing loading. The cool part was that we atleast caught the mishap on video.

[Ion01]

	Quote:
	The cool part was that we atleast caught the mishap on video.

Yea, I always feel a loit better about crashing if someone, even just observers, get some enjoyment out of it. That was some really good flying up to that point. Nice job!

[sprice50]

Man, that looked fairly devastating! Is it repairable?

[why_fly_high]

Matt,

Sorry for your loss.

You are a very honest person to admit fault. After watching the video if you had said that the rudder servo failed hard over I would have believed you.

Dan

[Matt Merciez]

	Quote: Originally Posted by sprice50
	Man, that looked fairly devastating! Is it repairable?

Definately not repairable (atleast not by me).

	Quote: Originally Posted by why_fly_high
	Matt, Sorry for your loss. You are a very honest person to admit fault. After watching the video if you had said that the rudder servo failed hard over I would have believed you. Dan

Thanks Dan. The rudder servo was definately fine. All the electronics have been pulled from the plane and sent back to JR for evaluation. Two of the aileron servos were stripped from the impact and will require new gears.

[bodywerks]

It falls like a brick because it is a 16 pound biplane with flying wires for extra drag to boot, and it only has 1440 squares. I'm sure it flew plenty light under power, but without it, it is going to be a lead sled. Mine will be 14 pounds, max, for that reason alone. P2W won't be the issue since it is going to have a BME 55 in it...
sorry for your loss!

[DStJohn]

Sorry for the loss, it was a very pretty model.
After watching the video and stepping through frame by frame, I don't think it was pilot error. It does not look like a typical stall/spin. Plus after the plane rolls on it's back, it stops spinning and goes straight down. If it had stalled/spun, it would have continued to rotate. I suspect a radio hit that rolled it over and then it (unfortunately) took a dirt sample. It does look like it was flying good before that. From your description, this model may be better off with something like a Moki 210 rather than a gasser

[YaKs are BeSt]

oh right rudder, that would do it turning at low speed like that. but it did look like it snaped a little worse than other planes might, but we dont know how much surface movement went in the direction of the spin to cause it.

[bodywerks]

He was on high rudder rates and low elevator rates.

[JoeAirPort]

The beginning sure looked like a classic tip stall. Maybe that rudder input at the wrong time induced it. 15 pounds at 1440 squares is not bad IMO. Should not be a wing loading issue. I'd say there was a defect in the plane from your comments about it landing like a brick. Not a bipe expert but the main wing incidense is important from everything I've learned. If the top was off that much it could have affected the landing in a bad way. The engine up/down thrust could also affect landing.