worldmodelsmach1

My Feedback: (1)

Could the camera sliding back caused a severe CG change? I had that happen with the batteries with my Extra 260 but in that case I brought the plane down with only a broken prop on landing... Sorry for your loss.

-Chris

PS did the airplane fly and differently (Ex. more nose or tail heavy) with the camera installed?

DelGatoGrande

My Feedback: (23)

Guys you have the owner say that the canopy flew off during the knife.

Who sed nose section broke away from main fuse? try to keep up with the senario please!

Richard try read the post before:no canopy DID NOT definitely stayed until impact

No there was also no wing delaminating at the leading edge to cause the violent pich up.

Because the jet doent SPINS to the ground.(if owners description is not good for you)

What i see untill 6:07 where the jet is still well

it has enter a knife loop! wich show too much rudder throw and canopy didnt cope with the side presure because pin wasnt all the way in..



(always my opinion boys...thank you for your time reading me)

DelGatoGrande

My Feedback: (23)

changed my mind im with Chris!

time for me to jump out of this one cause it starts geting nowhere

gone to fly/over +out

SAP_2000

How could a de-lamination of one of the wings or stabs cause such a violent pitch up in knife edge??

A servo going bananas, servo or control horn breaking, control surfaces falling of etc. could not cause anything near that knife edge pitch up... Any loss of control surfaces including vertical would probably cause a much more gentle pitch down, but no way a violent pitch up in knife edge (IMO).

Something massive broke, and I just can't see how anything related to the install could cause anythin near what we are seeing in the video...
I have never seen anything like this in my 10 years and thousands of flights, let alone seen in vids or read about either.

A structual failiure of the nose bending away from the fuse could IMO explain 1: the violent pitch UP. 2: the rear canopy blowing off because of the air pressure inside when the gap opened on one side as the nose broke away from the rear section. 3: the one piece shaddow if the nose was folded alongside the fuse to some degree.

It would be very helpfull if the author could describe more in detail what he saw when it happened, but I understand the is a language problem. Maybe he could tell his full story in Spanish, and the one of the many spanish talking people here could translate??? Just an idea....

rbean2

My Feedback: (3)

If the canopy DID NOT stay with the plane, then how do explain the video/audio recording of the fire starting, the shadows of the smoke and the continual crackling of the fire? Was it a miraculous coincidence that the departed canopy(with camera) fell exactly onto the burning wreckage? I think not! Instead of babbling on, watch the video again, listen to the video AGAIN and then maybe, maybe you will understand how the canopy is still attached to the fuse. The pilot probably did see something fall off, but in the excitement of seeing his hard earned money fluttering to the ground, he was probably incorrect.

Richard

SAP_2000

Yes. Time to go fly when you can't find a credible cause to make what happened the owners fault.
Seen very often here on RCU...

George: Before you go out and fly: Please explain how that extremely violent pitch up is physically possible with the airframe in one piece when the plane is flying with good speed in knife edge?

Very interested to know...

invertmast

My Feedback: (23)

if the stabilizer pointed toward the sky were to suffer a partial delamination, it "could" of caused a large increase in drag on that side of the airplane causing an abrupt and instant pitch up of the nose. I've seen stabs that were mounted on "tubes" do similar things during knife-edge. The stab broke free from its mounting bolt, twisted 90* so its chord was now perpendicular to the flight direction and a somersault began.

If the servo went to full right rudder from what was being used for the right rudder knife-edge a Pitch up would of been seen, not a pitch down.

rbean2

My Feedback: (3)

Futhermore, you can here the engine shut down and upon impact of the ground you can hear the turbine slowly grinding to a stop, a small pop, the sound of fire, the reflections of the rising smoke on the canopy, the hissing of an air tank releasing the pressure, the continually rising sound of the fire and finally the voices of the rescuers arriving at the scene. I doubt very much they would have gone looking for the canopy before getting to the plane. Also, I should not of used "babbling", my apologies.

Richard

as722

My Feedback: (1)

Looking at the video and it looks like the plane didn't pitch up, it looks like the camera moved as soon as the air hit it therefore changing the angle of the view finder.

Albert

DelGatoGrande

My Feedback: (23)

Hey Staale! i can only guess my friend that too much rudder input is the reason..
it was the first knife of the owner with this airframe and he probably set it up toomuch than nesecery..

you take care my friend

best regards
George

SAP_2000

If so you would probably see glances of the canopy frame. + I think I can se the nose of the plane all the way down...

Glad I was not on board

SAP_2000

After flying knife edge for several seconds... And, do you really think the rudder is that effective?

You also take care

marquisvns

Last weekend my Gripen's canopy blew off, happened just on the down wind pass right after take-off. I bet I didn't secure it well [&o]
Subsequently had to fly 8 minutes at half to 3/4 throttle at low airspeed for it to grow lighter before landing.

I thank these scale soaring guys there to call out "I got it" as soon as it happens, and marched on out to retrieve it for me.

Barry

marquisvns

Also, I thought I was flying straight and level, but it knocked off a wing tip missile rail as well, cuz the soaring guys couldn't quite make it out what that piece was.

Koenieboy

Last year I lost the engine hatch of a Skymaster MB-399 of a friend. Also during knife-edge (20th flight)...
The engine-hatch was attached like it came out of the box. But the hatch was to flexible. I had a safe landing.

Lesson learned: spent a bit more money on planes with german engineering behind it :-). They are built to last.

It was an early kit, 5years old I think. But this my not happen in my opinion....

Airplanes400

My Feedback: (349)

You're all wrong ... the jet was shot down by an air-to-air or surface-to-air missle.

Geeze, doesn't anyone understand the power of 100+ mph wind getting under the canopy and blowing it off?

marquisvns

I thought my post confirms to at least to some degree that the lost of this dragon's canopy was probably not due to latching issue.....

Anyway, sorry about your lost Luis

willig10

Bottom line guys is this.

This airplane should have been able to handle all maneuvers including knife edge without the damn canopy which by the way is a 2 piece canopy i.e. forward wind screen and aft canopy section falling off. The OP said he was sure the latching pin was installed and secured properly.

The movement of the forward wind sill just forward and below the HUD glass is not an optical illusion. Something is moving and and it definately needs to be reinforced. As I stated earlier, there needs to be some fuselage formers installed to reinforce the nose and cockpit floor section.

Air loads etc. on this caliber of jet should not deform the airframe in flightat all, period.

Glenn

Gene Margiotti

My Feedback: (4)

Ditto what Glenn said.[8D][8D]

Gene

reyn3545

Everyone has an opinion on this one, so here's mine....

I'm assuming that in the early part of the video, the pilot mounts the cockpit (camera attached) to the fuse, then installs the canopy. You can see the canopy in his hand for a second, so I am assuming the cockpit and canopy are 2 separate pieces. There definately is a forward section of canopy that is always attached to the fuse.

At the moment that something goes wrong, I think the violent shift upward is nothing more than the camera shifting inside the cockpit. I can only guess that it was shifting due to airflow. Did the canopy come off? I don't know. More on that later. the camera returns somewhat to its original location and we can see the jet immediately start spinning violently.

That's what needs to be answered... what would cause the jet to spin out of control from a knife edge? You can tell from the brief shadow at 6:10 that the fuse is generally still intact, the wings and vertical stab are at least still connected to the plane.

There's not a huge aileron load in a knife edge, so I can't imagine that the ailerons were causing the spin. If the rudder failed, you would think the plane would continue to fly, maybe difficult to control from knife edge, but not causing that kind of violent spin.

The plane was certainly in a knife edge attitude at other times during the flight with no apparent problems, but I understand that aileron/elevator turns don't put the same load on the airframe as a knife edge pass.

So.. something failed, and the jet spins violently to the ground. I've seen lots of canopies blow off but admittedly haven't seen a what happens when a canopy blows off of this particular jet. I would think that if the canopy blew off of this jet, the cockpit would soon follow, and our pilot would have both the canopy and cockpit as evidence. The cockpit stayed attached to the fuse (I can't imagine that there's anything other than simple alignment tabs to hold it on) and the only thing to hold it to the fuse would be the canopy frame.

I don't think the canopy blew off. I don't think a control surface, servo, or servo mount falied. Something immediate and violent happened to this airframe.... structural. The image at 6:10 shows that the wings are connected, but other than that, we don't know anything about the integrity of the fuse. It could have been a collapse of the fuse itself from the side air forces, it could be a delaminated wing surface, although the plane certainly experienced higher leading edge forces during previous flights and maneuvers.

I think the fuse failed, forward of the wing, and the forward portion probably turned a bit in the same direction as the rudder was deflected. that allowed air to enter the fuse, probably from below the cockpit (causing the camera to jump upward briefly) and the failed integrity of the fuse cause the immediate spin, from which the pilot tried to correct, then he did the proper thing... shut the turbine down and start praying.

I guess there's no way to tell from a burnt up pile of plastic and wires exactly what went wrong, and I guess, to some extent, I can't blame Skymaster for taking a cautious approach to accepting blame for the failure. We all assume a certain level of risk every time we head out to the field. Hopefully Skymaster will make a legitimate offer to offset the possibility that the airframe was to blame. The aiframe is just a small part of the pilot's loss, and I think the pilot assumes the risk of inspecting the airframe. He can either add support to areas of concern or return it to the dealer before he installs the other components that make up our very expensive toys. Today's vacuum sandwich construction processes produce some very detailed, beautiful airframes, but at the end of the day, it's just compressed foam with epoxy to give it stability. One little air pocket in the wrong place can lead to a disaster.

MNModels

Nobody in the world has more hours on a Dragon and have crashed more Dragons than me. So that make me some sort of expert. I have lost canopies of Dragons that struck flying surfaces and every time i could land with no problem. I have flown Dragon with 8kg ,12kg and 16 kg turbines. No problems. Numerous Dragons have been sold from the balsa wing versions to the composite versions. None (even with 16kg thrust) was ever reported with nose sections blowing off or damaged. This does not say that all Dragons build was perfect. But most of them with exceptions here and there like all man build items.

Over 20 years flying Jets i have lost 5 jets. Completely burnt out like Dragon at hand. None of it was my fault and yet no manufacturer have ever replace anything. Not even at a discount price. I lost a Dragon with JR8411 aileron servo packed up. Lost it neutral. Rolling one way then other way till nothing left. Who is to blame?

I lost a Hawk with brand new Jetcat P160 that threw a blade in air destroying everything. Who's fault? I lost a Kangaroo going into failsafe destroying itself. Who was to blame?...The list can go on and on...

But in my opinion any manufacturer can not just go and replace everything without proof.

And i am sorry for Luis's lost. But the video proof nothing. All speculation. To open up another can of worms: Putting a cell phone in a cockpit on 2.4 may not be the wises thing to do. There are a reason why no cell phones are alowed on the flight line.

Until new evidence shows up nothing more to say.

Regards

Morne

jthomas235

My Feedback: (2)

I lost my Dragon at the Wilson, NC jet rally a few months back and appears to have been due to a structural failure caused by the failure of the mounting straps to the exhaust tube. Kind of hard to be 100% sure, but this is what several pioneers of jets (and I won't list all their names) determined after looking at the carnage. To clarify, it appears the exhaust tube shifted to one side or the other allowing the turbine exhaust to contact to the inner fuse. The fuselage began to fold right in front of stab. What I first noticed was the lack of rudder or elevator surfaces.........no wonder, all wiring was burned to these 3 servos. I had no stab control and could do nothing but shut down turbine and watch it hit the ground. I was coming out of the top of a split S and did notice the fuse start to fold on the vertical decent. The exhaust tube did eventually depart the fuse on the way down and was found 100 ft. behind the impact area.

This is what I think caused the failure of the exhaust tube mounting straps: I flew the Dragon without the front nose door. Without the door, it really made a cool howling sound and one of the reasons I bought this plane. The sound was like a second turbine type noise that would make the hair on your neck stand up on a high speed pass. I believe the excess air flowing through the fuse put stress on exhaust tube mounting straps. It was not clear to me if the pilot was flying with or without nose door in this post.

I found no fault with Skymaster in my case. Maybe I should have used the nose gear door or reinforced the exhaust tube mounting straps. I will own another Dragon one day. One of the best jets I've ever flown and for $1700, a heck of a deal for this size aircraft.

The pilot said he saw the canopy fly off. Maybe something else flew off? He should have been able to locate the canopy upstream of the crash site if this was the case.

I have safely landed my flying partners Dragon when the canopy came off in flight and it did not affect the way it handled at all. BUT, it was in level flight and at about 75% power when it happened. We saw something fly off the plane but did not know until we landed what it was.

What I think happened in this situation was that the canopy DID come off in flight and due to the knife edge position, loss of more weight ahead of the c/g and pressure of air entering rear of fuselage, put the aircraft in a tail heavy condition, lots of rudder dialed in and it snap rolled in. Fly a Dragon with the c/g 1" further back from the recommended c/g and pull on the elevator a little.........you'll be in a snap before you know it. But, easy to recover from if you just ease off the elevator a bit.

John

Woketman

My Feedback: (6)

After viewing the vid, this is my take: Note that whatever the camera and the little fake HUD are mounted on moves relative to the outer top of the fuselage, in front of the canopy. You can easily see that anytime he is pulling a lot of Gs (such as at the bottom of a loop), the top of the HUD brackets are almost even with the top of the exterior fuselage. The rest of the time (near one G), they are well above it. So there is some relative G related motion between the thing the cam is on and the fuselage, not a lot, but some. I think that the wiggly-ness of the video that someone mentioned (like on the takeoff roll) is an artifact of the way that the camera scans the image. You see that a lot with vids exposed to some high frequency vibes.

I think the guys that said that the fuselage folded are correct. Note the suddenness of the failure. It is so damn rapid that it breaks the mounting of the HUD and shifts it. That is VIOLENT, cause that HUD does not have a lot of mass at all. I think what happened is that the large assymmetric airload on the fuselage side during the knife caused a large bending moment in the fuselage (obviously). Then, the side in compression, trying to react said bending moment, failed in compression (a stability failure in my business, basically long column instability). As soon as that happened, the fuselage experienced large deflection, and that caused the aft protion of the canopy (the removable part) to part ways with the airframe (what the pilot saw leaving the plane). The fact that this happened on the very first time he did a knife edge lends credence to this scenario. Apparently, the fuse was nowhere close to strong enough for the knife edge side loads.

If I am right (and I think I am) then Skymaster needs some additional formers in the forward fuselage or carbon or both. It is an easy fix. They also owe him another plane.

Woketman

My Feedback: (6)

PS. I think that even if my scenario is not 100% correct, one thing is for sure: the very first time it was put into a knife, something structural gave up the ghost FAST. That tells me the airframe had some sort of issue. It should easily handle those maneuvers.

reyn3545

I'm no structural engineer, but I agree... from the limited info we can see, it sure looks like a structural failure. Maybe the pilot cracked the fuse while he was building it... I'm not trying to blame anyone for anything here... but it sure looks to me like the fuse caved in, resulting in an impossible to control aircraft.

No one owes anyone an RTF jet... but I would hope, that based on the apparent data from the video, Skymaster would offer him a deal.