RE: video: 20 ft wingspan B-24 crash on maiden flight....  
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All Forums >> RC Airplanes >> Crash & Rebuild >> RE: video: 20 ft wingspan B-24 crash on maiden flight....
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RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/2/2004 2:49:47 AM   
teryn1


 

Posts: 282
Joined: 12/31/2001
From: Green Valley, AZ, USA
Status: offline 		William, a great point, that was never touched upon. It's possible that the wing was deforming in flight. I did watch the building proccess of the plane over several months and I would venture to say, that more likely, the vertical tail was crooked and/or asymmetric thrust were the contributors to the left yaing moment seen in the video.

And yes right rudder would have really helped but I did not see any inputs on the video (or on TV)....

(in reply to William Robison)
       Post #: 76

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/2/2004 4:12:12 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		teryn1:

If he had a sloppy fit of the locating pins for the outer panels, letting them twist a bit, it could have done the same thing even without twisting the structure.

In the video one wing panel was seen pretty much intact after the crash. If it hasn't been used to cook a hot dog you could check it.

Bill.

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       Post #: 77

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/2/2004 5:15:59 PM   
randall1959



Posts: 863
Joined: 8/29/2004
From: Bolckow, MO, USA
Status: offline 		Unfortunately there appeared to be so many things wrong, not just in the design and power, but also in the pilot's ability to control the machine so the real problem may never been found. It's still kinda fun to critique the flight and try to guess what caused it. It's our nature to be inquisitive.

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       Post #: 78

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/3/2004 1:50:55 AM   
volkan



Posts: 1836
Joined: 9/16/2003
From: London, UNITED KINGDOM
Status: offline 		VIDEO IS UP AND RUNNING AGAIN

check out all 129 videos at

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(they work now!)

Cheers
Volkan

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(in reply to randall1959)
       Post #: 79

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/3/2004 2:17:45 PM   
volkan



Posts: 1836
Joined: 9/16/2003
From: London, UNITED KINGDOM
Status: offline 		This may intrest you:

B25 Crash

RIGHTCLICK ---> SAVE TARTGET AS.

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       Post #: 80

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/4/2004 4:51:26 AM   
w4kv



Posts: 39
Joined: 6/19/2002
From: Pittsburgh, PA, USA
Status: offline 		I'm not too distressed with the wing flex. The plane was grossly underpowered, and the relatively steep turn obviously stalled the left wing==plop.

Rehashing previously mentioned stuff:
Poor judgment
- -Runup with bystanders as a safety(!) stop.
- -Initial flight on a turf field.
- -Initial flight in a crowded area. (Why did he turn left, anyway?)

Pilot error
- -All of the above
- -Slow takeoff run.
- -Excessive bank in slow turn. (I don't think rudder would have helped much.) There is a high likelihood that the plane wasn't properly trimmed prior to the first flight.

The pilot probably had little experience in flying a craft so underpowered, and he seems to have allowed things to get out of hand low and slow.

(in reply to randall1959)
       Post #: 81

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/4/2004 6:24:37 PM   
dag21463


 

Posts: 21
Joined: 6/10/2004
From: fishers, IN,
Status: offline 		I would like to put in my two cents now. About 8 years ago I had a C-130 with 4 4stroke 90"s. On the test flight I had one of those things happen that would make any of our hearts stop. As the plane left the ground the left wing started to drop but what I noticed the most was how much the plane was yawing. I start to feed in rudder and aileron. After adding full control deflections it was becoming quite clear very quickly I was in troble. I then pull the power back and put the nose down and had control back. Just be for I got to the ground I add some power back and nursed the plane back around the pattern and landed it. The next flight I made sure I had a lot more airspped before leaving the ground and I still could only barely control the plane. The torque of the engines was unreal. I ended up having huge rudder movements to control the yaw. In the video I dont see any rudder being add in. But the video is not real clear. If he would have kept the air spped up he might have made it. The plane seems controlable at first then as the airspeed bleeds of in the climb it looks as if the torgue takes over. Just a few thoughts.

(in reply to w4kv)
       Post #: 82

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/4/2004 9:41:39 PM   
Turbo442


 

Posts: 59
Joined: 9/12/2003
From: Cornelius, OR,
Status: offline 		Here is an interesting B24 crash.

Matt

http://rob.com/pix/matt

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(in reply to teryn1)
       Post #: 83

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 2:15:48 AM   
teryn1


 

Posts: 282
Joined: 12/31/2001
From: Green Valley, AZ, USA
Status: offline 		John,
As has been discussed (obviously, you have not read this thread completely), the pilot did not intentionally turn the plane. There is more to this than meets the eye. Looking closely at the video, you will see full right aileron inputted from the moment of takeoff. This indicates that the pilot was either trying to turn right or maintain level flight (the latter is the scenario). I know for a fact that the pilot was not turning left intentionally, because there are high trees to the left of the crash site. Also, the plane was not in a steep left turn (as you indicate) until it encountered a mild stall. More importantly, the noticable LEFT YAW was the instigator for the crash in the first place.

And, by the way, how do you trim a plane before the first flight as you indicate?

Teryn

< Message edited by teryn1-RCU -- 10/5/2004 3:51:49 PM >

(in reply to w4kv)
       Post #: 84

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 5:52:58 AM   
MikeMc



Posts: 572
Joined: 2/19/2004
From: Union City, CA, USA
Status: offline
quote:

ORIGINAL: volkan

This may intrest you:

B25 Crash

RIGHTCLICK ---> SAVE TARTGET AS.


Prefect exmaple of correct camera technique. At the very end what appears to be panic on the part of the camera man really is not. See there was actually a 6' high visual obstruction that would have prevented video of the actual impact but at at the very last moment the camera man jumped up on his buddy's back to get the impact. You can hear them both talking still. Nerves of steel and quick thinking resulted in excelent camera work there. Obviously professionals at work.

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(in reply to volkan)
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RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 6:17:59 AM   
jameschen0702


 

Posts: 117
Joined: 7/18/2004
From: Irvine, CA, USA
Status: offline 		well..some of us crash small planes, some crash slightly bigger ones and some crash graceful giants! skill is from those who can make even a crash look pretty

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RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 10:20:54 AM   
Jimmy Bananas


 

Posts: 886
Joined: 12/30/2001
From: Urbandale, IA, USA
Status: offline 		I was just wondering if the pilot preformed the power to weight ratio test..In other words,if the plane weight 50 Ibs,then the thrust should be at least 25 Ibs....I do mine with a digital fish scale...Also some right thrust on the right side engines,might of helped...Sorry to see such a beautiful plane bite the dust....

(in reply to volkan)
       Post #: 87

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 1:47:56 PM   
dag21463


 

Posts: 21
Joined: 6/10/2004
From: fishers, IN,
Status: offline 		Was wondering where did you come up with that formula for power to weight? Real planes have nowhere near a 50% power to weight ratio. I had a 54 pound b-29 that had 13 pounds of thrust and the plane flew great. Also I fly a 160 hp piper(full scale) and it weighs 2440 pounds and the thrust of its 160 hp engine is around 575 pounds of thrust while sitting static on the ground. An air plane only knows one thing. AIRSPEED. thats what they told us in school 20 years ago. Now I know you have to account for the drag of the aircraft. I also have flow 1200 pound experimental aircraft that had only 85 ponds of thrust out of an utralite engine. Even airshow pitts that weight in at 1200-1800 pounds (S-1 or S2b type) only have 600 pounds of thrust. There are many programs out there that you can enter the airfoil of you prop, its size and the cord of the blade at different places along the cord, then inter the RPM you want to turn it and it will give you the thrust you want. Dont get me wrong I love thrust, I have a 1/2 scale pitts with a 16.5 hp engine that produces 85 pounds of thrust and the plane only weights 45 pounds. Also you are correct about the thrust. I had all of my b-29 engine 2.5 degrees to the right. I know that a multi you should have the engines thrust pointing away from the fuse alittle (as not to have an critical engine in the event you loose one) but I liked having the plane trimmed for straight flight. And the 29 still flew OK with 1 engine out. You can see my knew b-29 14' wing span in my gallery.

(in reply to Jimmy Bananas)
       Post #: 88

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 2:28:00 PM   
Mhale71


 

Posts: 647
Joined: 10/8/2003
From: sydney, AUSTRALIA
Status: offline 		Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!! Fight!!

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       Post #: 89

RE: video: 20 ft wingspan B-24 crash on maiden flight.... - 10/5/2004 5:03:56 PM   
raptor11


 

Posts: 23
Joined: 12/15/2003
From: In the Middle, GA, USA
Status: offline 		What slays me is that if it were a successful takeoff and flight, I would be reading a whole different point of view. Go figure.

< Message edited by raptor11 -- 10/5/2004 5:06:11 PM >

(in reply to volkan)