Go Back  RCU Forums > RC Airplanes > RC Jets
 Safety Matters >

Safety Matters

Notices
RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

Safety Matters

Old 06-15-2006, 01:13 PM
  #226  
My Feedback: (81)
 
Join Date: Jan 2002
Location: Apple Valley, MN
Posts: 3,236
Received 3 Likes on 3 Posts
Default RE: 2 death 4 wounded in model airplane crash

Lee, I was sorry to see your MiG go in. I was the guy who splated the 124 inch Avenger the day before. Good luck with future projects.

Everyone fly safe...that is the best insurance you have.
Old 06-15-2006, 07:17 PM
  #227  
My Feedback: (2)
 
Silver182's Avatar
 
Join Date: Dec 2001
Location: Littleton, CO
Posts: 1,095
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash

ORIGINAL: Woketman

Lee, was the switch that was found in the "off" position oriented such that the extreme deceleration at impact could have turned it off? In other words did you have to push it aft to turn it on?

Thanks and sorry to hear about the Mig. I've seen it years before in person and it was beautiful.

Hi Mark,
I thought I was the only one on this forum that would had a thought like that.... we always used to mount our switches so that upon impact "maybe" the switch would turn off.. preventing a possible electrical meltdown! Mark you may have just dated yourself

The fact is both switches were mounted with Velcro in a cushioned manner. I try not to hard mount anything that could self destruct...comes from my racing days. I did not paint an indicator color on the portion of the slider so that it would be visually obvious if it was ON or OFF. I could have and should have... Just another mistake I must correct for the future.

Thanks for the thought.. but I am sure now after retracing what I did on the ramp during startup.. yep I just neglected to set both switches to the ON position. As I stated before... sort of.. several things ran through my mind... until I was able to see the physical remains. My spotter Jerry, thought possibly a flap servo could have bit the dust... but on further consideration I did try to counter the roll to the left with right aileron with no visible change during the spiral in. The idea of R/F interference was strongest on my mind during the drive around to the crash site. During the drive, I turned my Icon R-2 scanner ON and checking the Channel I was using.. it was clear as could be! Of course the idea of a shooter passed in and out of my mind because Egils and my flight was so impromptu there was almost Zero chance of that.

I was sorta stunned when I discovered the switch.. but it didn't take long for me to figure out that it must have had something to do with the crash... as you know anything out of the ordinary in aviation is one of the best signals we have.... the secret is learning to never but never letting those anomalies pass by un-noticed.
Lee
Old 06-15-2006, 09:17 PM
  #228  
My Feedback: (2)
 
Silver182's Avatar
 
Join Date: Dec 2001
Location: Littleton, CO
Posts: 1,095
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash


ORIGINAL: BaldEagel

Silver

Just for your information the site from which you operate would not meet the requirements of our insurance or the "Air Navigation Order" for aircraft over 7Kg (15.5lb) in the UK as it is too close to "People, vessals, vehicles or structures" and that is in a country with restricted land mass compared to the US.

MIke
Hello Mike,
Your point is close to being spot on...I my self have been in sorta of a battle over the past year with the majority of our club members but not related to our north/south runway.. rather our longest (690 feet and most coveted) east/west runway! Until last year I was one of only two club safety officers for the last 14 years. I resigned over the fact that our east/west runway now as of last year.. has many new and very active campsites directly to the west of that runway. I believe that runway should be closed during the summer months, (boy did that stir up a hornets nest).. those campsites are full almost every day! See the newest campsite locations aerial view (below), and our east/west runway orientation & distances. In my opinion just too many possible targets WHEN & IF something goes wrong! The size, type, and speed of the aircraft in my opinion really doesn't make a difference.

Strange as it may seem the heading & direction of my MIG's "final approach" (beginning to turn base leg a little deep) is just about the only higher probability campsite risk factor heading when we are using the north/south runway. When that runway is active for the most part all flight is conducted to the east of a line extending north & south from the north/south runways east edge. A few cars, never many as this is the back door entrance to the Park, and the south entrance Guard shack are the only high risk targets within that flight area.

Mike you must understand we are out hear in the Great Western U.S.A., where on a good clear day... and there are many... you can see for a 100 miles. Because of this openness and relative wildness we are slow to give up anything that will restrict us.
Lee
Attached Thumbnails Click image for larger version

Name:	Xu62765.jpg
Views:	14
Size:	296.1 KB
ID:	478233  
Old 06-15-2006, 10:07 PM
  #229  
My Feedback: (6)
 
Join Date: Dec 2001
Location: Slidell, LA
Posts: 5,432
Received 8 Likes on 6 Posts
Default RE: 2 death 4 wounded in model airplane crash

Lee, you got me on the switch orientation!!

I am not sure if you remember, but I was at a Lockheed Martin seminar at the Deer Creek facility about 5 years ago or so. I went out to your Chatfield facility one afternoon. There were a few prop guys flying, no jets. I asked if the guys knew you and Dean and several said "yes". I can remember seeing a lot of clear, open ground, but I think one guy mentioned the camp ground (maybe under construction then?). I remember it was very windy that day. I bet its like that a lot there. Great facility though!
Old 06-15-2006, 11:32 PM
  #230  
GSR
My Feedback: (145)
 
Join Date: Oct 2002
Location: Seal Beach, CA
Posts: 1,970
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 death 4 wounded in model airplane crash

Looks like a nice flying site- As a campground it looks like the surface of the moon-Guess its for campers that aint into scenery. Scott
Old 06-16-2006, 02:20 AM
  #231  
My Feedback: (4)
 
Eddie P's Avatar
 
Join Date: Feb 2003
Location: Reno, NV
Posts: 1,915
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 death 4 wounded in model airplane crash

Here is a brief moment of comic relief.

http://www.youtube.com/watch?v=ILwJW...&search=Flying
Old 06-16-2006, 04:24 AM
  #232  
 
BaldEagel's Avatar
 
Join Date: Oct 2005
Location: Kent, UNITED KINGDOM
Posts: 9,672
Received 5 Likes on 5 Posts
Default RE: 2 death 4 wounded in model airplane crash

Well I am glad you think its funny to see aircraft being flown in inapropriate places, out of control and endangering humans, also highlighting the fact that model aircraft are dangerous. Invalidate your insurance anyone.

Mike
Old 06-16-2006, 05:26 AM
  #233  
My Feedback: (2)
 
Silver182's Avatar
 
Join Date: Dec 2001
Location: Littleton, CO
Posts: 1,095
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash


ORIGINAL: F4u5

Lee, I was sorry to see your MiG go in. I was the guy who splated the 124 inch Avenger the day before. Good luck with future projects.

Everyone fly safe...that is the best insurance you have.
Boy weren't we lucky to get those smacked Ass award T-shirts.....tell all the guys from Minnesota thanks for coming down to fly with us.
Lee
Attached Thumbnails Click image for larger version

Name:	Ro41888.jpg
Views:	12
Size:	40.3 KB
ID:	478357  
Old 06-16-2006, 05:34 AM
  #234  
My Feedback: (2)
 
Silver182's Avatar
 
Join Date: Dec 2001
Location: Littleton, CO
Posts: 1,095
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash


ORIGINAL: GSR

Looks like a nice flying site- As a campground it looks like the surface of the moon-Guess its for campers that aint into scenery. Scott
Scott,
Hehehe.... well the area doesn't in the summer look so bad.. but your right it does make all of us wonder why anyone would drive from home stay within the city and camp in these spots. I've often wondered if some guys use there campers like motels..hehe get it girl friends.. We wished the state would never have built the damn campsites.. but the old saying you build it and they will come sure applies here..
Old 06-16-2006, 10:52 AM
  #235  
My Feedback: (4)
 
Eddie P's Avatar
 
Join Date: Feb 2003
Location: Reno, NV
Posts: 1,915
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 death 4 wounded in model airplane crash

ORIGINAL: BaldEagel

Well I am glad you think its funny to see aircraft being flown in inapropriate places, out of control and endangering humans, also highlighting the fact that model aircraft are dangerous. Invalidate your insurance anyone.

Mike
Glad to see we still have a sense of humor, I was a little concerned about that frankly but now that has been laid to rest
Old 07-03-2006, 09:18 PM
  #236  
Senior Member
My Feedback: (1)
 
Jackjet's Avatar
 
Join Date: Dec 2001
Location: Apple Valley, CA
Posts: 1,137
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash

Sorry this happened to you.......... a $29 switch causes a $20k jet to crash.......damn.....been there............

Jackjet
Attached Thumbnails Click image for larger version

Name:	Ig12727.jpg
Views:	10
Size:	25.2 KB
ID:	486563  
Old 07-07-2006, 03:27 PM
  #237  
Member
 
Join Date: Feb 2006
Location: , CA
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash

What does the combustion chamber have to do with anything?
Old 08-17-2006, 12:03 PM
  #238  
Junior Member
 
cr2k's Avatar
 
Join Date: Apr 2006
Location: Madera, CA
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Safety Matters

While this may not be a "JET" it is an RC aircraft. The point should be that ALL of our "TOYS" can be deadly. A jet can be even worse as it flys much faster and has a very pointy front end.

Lawn darts were outlawed and they only weighd about a pound and were hand launched and caused deaths.

Jets weigh 15 to 50 pounds and are powered by an engine that propells them to over 200 mph!

That is why it is of utmost imnportance to call "Out of control" when you have lost control, to alert people.

I have posted signs around our field saying that R/C aircraft can go out of control and come down anywhere - Be Aware Look Up.
Old 08-20-2006, 01:06 AM
  #239  
 
Join Date: Jul 2006
Location: Ann Arbor, MI
Posts: 1,588
Received 0 Likes on 0 Posts
Default RE: 2 death 4 wounded in model airplane crash

ORIGINAL: mikedenilin

I never like these 40% 3D planes. They are like flying lawnmowers without a safety cover. The spinning prop blades are most lethal. I think that these 2 viticms were killed instantly by the spinning props.

I strongly believe that jets are safer than these large scale planes. Jet pilots are more aware of safety operations due to the waiver requirements. I really think that AMA should mandate a waiver program for the 33% upper planes or for large engine placement. I have seen some club flyers with wallets bigger than their brains flying these giants recklessly. They should be certified for safety reasons.

Any thoughts on this?

Mike
First, in view of the incident, I feel the same way about regulating anything 25% scale and larger. There is just too much that can happen with a model that big, and one safety oversight can kill somebody or change a life forever. I have read about the fail safes in jets that shut down turbines when contact with the transmitter is lost. I actually think that should be a requirement for anything that runs by remote control, whether it be a car, plane, boat, or robot. After reading this thread, it causes me to think about more than just the cost of the model.

On my first flight, the instructor and several other people asked me how long I charged the batteries in the plane's receiver. At first, I told them that I charged the batteries initially for 15 hours, as per the instructions. My plane was grounded for that day as a result of my answer. They told me to take it home, drain the batteries, and run the charger for 24 hours. I simply did what I was told, and did not question them. I saved the photos to the two incidents discussed here too, so I can perfectly understand WHY they were so serious about the batteries. I brought the model back to the field a few days later, and everything checked out fine during the range check. I followed their instructions, again, no questions asked. That day, I got two flights in safely, my first flights on the trainer box.

The duration of a battery's charge does not tell me everything I want to know about a battery's health, unfortunately. My model doesn't have a volt meter that can tell me what the charge level is on the batteries before flight. Although that UAV (it's a model aircraft to some, but I consider it as an unmanned aerial vehicle) is airworthy, I took it upon myself to take it out of service for that very reason. That plane is not going to fly until I get a volt meter that will tell me how good the batteries are before I even start the engine. Why am I doing this? Because the field is close to an expressway and a residential area. If a plane ever loses contact with the transmitter because of undercharged batteries and hits a car, hits a house, injures somebody, or kills somebody a few miles away, you can very well bet the authorities WILL find out who that model belongs to. Needless to say, it WILL NOT be mine if I can in any way help it. If somebody gets injured or killed, the cost of a new plane to replace the one that gets lost is the the last thing to worry about.

NorfolkSouthern
Old 08-20-2006, 11:33 AM
  #240  
My Feedback: (4)
 
Eddie P's Avatar
 
Join Date: Feb 2003
Location: Reno, NV
Posts: 1,915
Likes: 0
Received 2 Likes on 2 Posts
Default RE: 2 death 4 wounded in model airplane crash

ORIGINAL: NorfolkSouthern

On my first flight, the instructor and several other people asked me how long I charged the batteries in the plane's receiver. At first, I told them that I charged the batteries initially for 15 hours, as per the instructions. My plane was grounded for that day as a result of my answer. They told me to take it home, drain the batteries, and run the charger for 24 hours. I simply did what I was told, and did not question them. I saved the photos to the two incidents discussed here too, so I can perfectly understand WHY they were so serious about the batteries. I brought the model back to the field a few days later, and everything checked out fine during the range check. I followed their instructions, again, no questions asked. That day, I got two flights in safely, my first flights on the trainer box.

The duration of a battery's charge does not tell me everything I want to know about a battery's health, unfortunately. My model doesn't have a volt meter that can tell me what the charge level is on the batteries before flight. Although that UAV (it's a model aircraft to some, but I consider it as an unmanned aerial vehicle) is airworthy, I took it upon myself to take it out of service for that very reason. That plane is not going to fly until I get a volt meter that will tell me how good the batteries are before I even start the engine. Why am I doing this? Because the field is close to an expressway and a residential area. If a plane ever loses contact with the transmitter because of undercharged batteries and hits a car, hits a house, injures somebody, or kills somebody a few miles away, you can very well bet the authorities WILL find out who that model belongs to. Needless to say, it WILL NOT be mine if I can in any way help it. If somebody gets injured or killed, the cost of a new plane to replace the one that gets lost is the the last thing to worry about.

NorfolkSouthern
Hi NS-

The battery voltage on NiCD or NiMH, sitting idle under no load, doesn't tell you much. You have to place a load on the batteries and then look at the voltage drop to determine the condition of the cells. There are a few ways of doing this but a high quality charger like a Schulze Camelian or similar, which can condition packs and cycle them, will give you a much better indication of the pack's health.

Besides the attention to the battery condition, which is very good when taken into context, it is also very important to concentrate on the whole airplane as a series of systems: flight controls, airframe, powerplant, radio link (airborne and TX), servos, etc.. They all play an important role and their neglect can cause any number of problems.

However, in the particular case in Hungary, the model airplane and transmitter seemed to have been in perfect condition. It appears a mobile radio station hijcked the frequency that was in use to control the model airplane, and caused the resulting lock out that led to the crash. This is very much an issue of how the event was conducted and the oversight of the event coordinators.
Old 09-01-2006, 02:50 PM
  #241  
 
David Gladwin's Avatar
 
Join Date: Feb 2002
Location: CookhamBerkshire, UNITED KINGDOM
Posts: 3,927
Received 146 Likes on 94 Posts
Default RE: 2 death 4 wounded in model airplane crash

So, some guys are putting 36 pound thrust engines into a Bobcat , an airframe originally designed for 12 pounds of thrust from a RAM 500, with not a mention of flutter protection. Sheer madness. Please discuss, or of course, we can all stand idly by and wait for someone to give this sport one big black eye, as BV, quite rightly, calls it.
Regards,
David Gladwin.
Old 09-02-2006, 11:35 AM
  #242  
My Feedback: (73)
 
wojtek's Avatar
 
Join Date: Dec 2001
Location: Virgin, UT
Posts: 4,385
Received 13 Likes on 10 Posts
Default RE: 2 death 4 wounded in model airplane crash

David, Since I can obviously assume you are referring to me here, let me correct some of your thinking. First of all the BobCat Composite is not designed for 12 lbs engines. In fact a 12 lbs engine will provide a very marginal performance on this airplane ( that’s just my personal opinion). A few things to be considered:

- my BobCat weighs in over 25 lbs dry, and wet is right around 35 with a full load of fuel and smoke oil. That’s barely over a 1:1 t:w
- I have reinforced several areas of the airplane, and am very aware of its physical capabilities.
- How come I don’t see you pointing out that people are putting 36 lbs engines in on Rookies, and Bandits ? ( I have seen these blow apart when yanked too hard ) or p200s and p180s on eurosports ( also an airframe prone to failure ) why are you not calling them “mad “ also ?? I sense a little bit of bias here from your end …
- The BVM BobCat is one of the most solid and robust airframes out there. It is a very compact design with a large amount of strength and list coming off of the fuse. The stabs are not flutter prone because of the boxed in design, etc …
- There are things that you can do with 36 lbs that any less would not be possible with… like 90 deg verticals out of a slow almost stalled pass ? of how about out of a tail slide ? I have had 2 occasions on landing where the extra thrust has also definitely got me out of trouble, and actually prevented an incident. Ever see a BobCat almost hover in inverted high alpha flight ? 36 lbs is quite useful here … not to mention the super acceleration the plane has right off the deck ..
- Throttle response: the 36 lbs engine I am using has almost instant throttle response, I can not get that out of most other engines of lesser power such as a p60, 70 or 120 ( which I used to have on this plane )
- There is a big difference with things done by a beginner, vs someone who knows what they are doing. I guarantee that a higher percentage of pilots using 12 lbs engines in BobCats are of danger to others vs those using 25 lbs or more … its not a matter of how much power .. it’s an issue of what kind of experience is behind it. Out of all the “dangerous” crashes I have ever seen ALL of them were due to inexperience of the pilot, or the builder.
- It is jets we are flying here, and we fly them because they are fast. The technology is here that allows us to have stronger airframes, more power. With safety and responsibility of operation in mind we can embrace these things in our hobby which were not available to us not so long ago. Promoting safety is one thing, going on a witch hunt is another. So David, please do not be like one of the monkeys in the analogy bellow.


Start with a large cage containing five monkeys. Inside the cage, hang
a banana on a string and place a set of stairs under it.

Before long, a monkey will go to the stairs and start to climb towards
the banana. As soon as he touches the stairs, spray all of the other
monkeys with ice cold water. After a while, another monkey makes an
attempt with the same result; all the other monkeys are sprayed with
cold water. Soon, when another monkey tries to climb the stairs, the
other monkeys will try to prevent it.

Now, put away the cold water. Remove one monkey from the cage and
replace it with a new one. The new monkey sees the banana and wants to
climb the stairs. To his surprise and horror, all of the other monkeys
attack him. After another attempt and attack, he knows that if he tries
to climb the stairs, he will be assaulted.
Next, remove another of the original five monkeys and replace it with a
new one. The newcomer goes to the stairs and is attacked. The previous
newcomer takes part in the punishment with enthusiasm! Likewise, replace
a third original monkey with a new one, then a fourth, then the fifth.
Every time the newest monkey takes to the stairs, he is attacked. When
all of the original monkeys have been replaced none of them have ever
been doused with cold water. Consequently, none of the monkeys know why
they are beating the newcomer or why they are not permitted to climb the
stairs.

Nevertheless, no monkey ever again approaches the stairs to try for the
banana. Why not? Because, as far as they know that's the way it's always
been done around here.



best regards,


Voy
Old 09-03-2006, 04:47 AM
  #243  
 
David Gladwin's Avatar
 
Join Date: Feb 2002
Location: CookhamBerkshire, UNITED KINGDOM
Posts: 3,927
Received 146 Likes on 94 Posts
Default RE: 2 death 4 wounded in model airplane crash

Let me absolutely assure you, Woj, there NO bias on my part. I am concerned at grossly overpowering ANY aiframe ALL of which have a finite structural strength. In fact I hold the BobCat in the highest regard both aerodynamically and structurally, I have built, own and fly two and even brought one from Australia to the UK for the summer, I enjoy flying it so much with its jetCat 70. The structural strength and build quality of SOME Composite ARF models was unacceptable as I found when building a Eurosport, which in my kit had some internal parts not even glued in. I was also absolutely amazed at the blistering performance of the comp BobCat of Jason Fletcher powered with an 18 pound Wren SuperSport and I will acquire one when Bob gets it back into production and power it with a Wren SS in due course. After seeing Jason's model flying I just can't see the point of more weight and double the thrust.

Just before seeing JFs BobCat I had seen at an earlier meeting a gas turbine powered model disintegrate in flight, it wasnt pretty. I KNOW this model was very well built but cumulative fatigue eventually caused its structural failure, even though it was not overpowered and not flown "hard".

Clearly my concern is not unique. In an interview in JetPower a year or so ago, Markus Zipperer of JetCat voiced his concerns, too, of grossly overpowering models, describing it as, if i rememeber correctly, as "madness "!

I will give you a longer reply if and when I see the other reponses to this issue but in my view it IS an issue which requires sensible and frank debate if we are to preserve our freedom to operate gas turbine powered models with little or no external regulation.

Regards,

David Gladwin.
Old 09-03-2006, 10:33 AM
  #244  
My Feedback: (73)
 
wojtek's Avatar
 
Join Date: Dec 2001
Location: Virgin, UT
Posts: 4,385
Received 13 Likes on 10 Posts
Default RE: 2 death 4 wounded in model airplane crash

David,

I really appreciate you clarifying your position on this and I do understand your concerns ( to a certain degree ) … “overpowering “ a plane can be dangerous… either a: if its done to an inadequately constructed airframe or b: flown inappropriately with the excess power. I think that a plane like a bobcat is just fine with a P70 type engine for general flying around, and yea, it will go pretty fast .. but I bet it wont go vertical out a nearly stalled pass, it wont get you out of trouble on an aborted landing as quickly, and will not have as great of an acceleration as an “ overpowered” plane .. the weight issue is not really an issue , you are talking the difference of a pound and a half between a 17 and a 36 lbs engine .. most paint jobs weigh more , and its things like lights , smoke systems, redundant batteries, detailed cockpits , etc that are what really add the weight up in the se planes. Also, going back to another point, its all about how the plane is flown and handled .. I bet I could take a Bobcat way beyond its structural capabilities on a P70, or even a P60 … its not the power, its how its handled, and what’s done with it … best example in my opinion is something like a rookie, which is very adequately powered with a 17 lbs class engine, .. but can you hover one with those 17 lbs ?? so would 36 be overpowering the plane ? or what this plane really needs to perform certain maneuvers ?

Best regards,


Voy



P.S.

Dave, just curious, does the water in the toilet really spin in a different direction when flushed than on our side of the planet ?
Old 09-03-2006, 03:30 PM
  #245  
 
David Gladwin's Avatar
 
Join Date: Feb 2002
Location: CookhamBerkshire, UNITED KINGDOM
Posts: 3,927
Received 146 Likes on 94 Posts
Default RE: 2 death 4 wounded in model airplane crash

Woj, I entirely agree, its WHAT you do with the power that counts, such as using it to take the aircrafft to structural failure :

When I pulled over 50Gs on the plane and actually failed the wing,

thats what I think is the real danger, and something which IS in our control and which should be absolutely avoided. !

The answer to your question is yes, Coriolis, just as the air flows in reverse around a depression or anticyclone, back to wind low pressure on RIGHT, Buys Ballots law.

Regards, David Gladwin
Old 09-03-2006, 05:33 PM
  #246  
My Feedback: (73)
 
wojtek's Avatar
 
Join Date: Dec 2001
Location: Virgin, UT
Posts: 4,385
Received 13 Likes on 10 Posts
Default RE: 2 death 4 wounded in model airplane crash


ORIGINAL: David Gladwin

Woj, I entirely agree, its WHAT you do with the power that counts, such as using it to take the aircrafft to structural failure :

When I pulled over 50Gs on the plane and actually failed the wing,

thats what I think is the real danger, and something which IS in our control and which should be absolutely avoided. !

The answer to your question is yes, Coriolis, just as the air flows in reverse around a depression or anticyclone, back to wind low pressure on RIGHT, Buys Ballots law.

Regards, David Gladwin

David, as i pointed out earlier, similar stress can be exerted one a BobCat ( or similar airframe ) with a p70 or even a p60 .... When I failed my wing ( which was actually just a crack in a rib which has since been repaired) the plane was being flow on only a 27 lbs engine. I don't feel yanking that hard on a plane is an issue if it is done at the right time and place. In this case, the plane had traveled 100s of feet past anyone, and was heading AWAY from anyone ( or anything else for that matter). Again, its a matter of what is being done and WHERE it is being done ..

Also, on the 50 G thing .. Though I do fly my plane very hard, 50Gs is not something that was applied intentionally, and you are 101% correct that it should be avoided !! ... If you read the rest of my post on the other thread, you can see how using dual rated got me in trouble there ( not switching to low where I want to add some serious elevator and ended up with double the intended throw ) Actually having had this incident has given me a good idea what the structural capability of this plane are, and in fact made me feel a lot more comfortable with upgrading to a full 36 lbs of thrust, and feeling safer flying the plane. I also now know by experience what points are prone to failure and how the wing components are stressed, which in turn has allowed me to properly modify and reinforce the plane as needed for safe operation to handle 36 lbs, and heavy G loadings.

Another thing to take into consideration is that over time structural components can fatigue, wings do flex, and pull back and forth on the glue joints, skins, ribs, etc … hard landing here and there can also cause hidden cracks, and damage that can add up …. My BobCat for example has over 100 flights on it so far .. its had some bad landings, and some minor damage here and there .. for this reason I have downgraded it back down to a P120 for power.. Just not worth risking it, though it could probably take another 500 more. As for the Rhino, it is going in a brand new BobCat which also has been now seriously reinforced. Its just a matter of being safe …
Old 09-04-2006, 03:27 AM
  #247  
 
David Gladwin's Avatar
 
Join Date: Feb 2002
Location: CookhamBerkshire, UNITED KINGDOM
Posts: 3,927
Received 146 Likes on 94 Posts
Default RE: 2 death 4 wounded in model airplane crash

May I just ask how you arrive at the figure of 50 Gs, calculation, measurement or just a guess ! After all, to achieve 50gs on a 35 pound model means the wing needs to generate 1750 pounds. 3/4 of a ton, of lift without stalling or failing structurally. I have never worked with numbers such as 50 G and dont have the data on the BobCat aerofoil to do the maths (or better, have them done for me by an expert on these matters). Curious. I am not an engineer but I know that fatigue calculations on metal airframes are very well understood, those on composite structures much less so, perhaps we could have some professional input on this matter of cumulative fatigue on composites.


Regards,

David Gladwin.
Old 09-04-2006, 08:58 AM
  #248  
My Feedback: (6)
 
Join Date: Dec 2001
Location: Slidell, LA
Posts: 5,432
Received 8 Likes on 6 Posts
Default RE: 2 death 4 wounded in model airplane crash

I would not say that fatigue is "very well understood" on metal airframes. It is understood to a degree, but less so than static strength. For example, on the External Tank for the Shuttle, we require a static strength Factor of Safety of 1.40 but we require a fatigue Life Factor of 4.00 on metals. Much higher due to greater uncertainty. We have a few composite parts, and I believe we use the same Life Factor. I know we recently had to test a composite part to demonstrate the LF of 4.00 for the recent PAL Ramp removal effort prior to STS-121. I think we had to test because we could not show the LF good analytically like we do with metal (using FLAWGRO, a crack growth program). I am not certain if we had to do this because composites can not be analyzed for fatigue analytically or if we just did not have the data so we opted for testing. I will know soon as I have been slated to take a FLAWGRO class taught by our Materials department expert. I will be sure to ask.
Old 09-04-2006, 10:33 AM
  #249  
 
BaldEagel's Avatar
 
Join Date: Oct 2005
Location: Kent, UNITED KINGDOM
Posts: 9,672
Received 5 Likes on 5 Posts
Default RE: 2 death 4 wounded in model airplane crash

Well guys can someone tell me has this become the general forum for safety matters? or are we just way off subject? does anyone know what has happened with the fatal crash in Hungury? was the local radio station transmitting ilegally? was the german pilot flying without a fail safe? has he been prosecuted?

These are all answers I would like to know, but do not seem to be on this forum.

Mike
Old 09-04-2006, 10:57 AM
  #250  
My Feedback: (73)
 
wojtek's Avatar
 
Join Date: Dec 2001
Location: Virgin, UT
Posts: 4,385
Received 13 Likes on 10 Posts
Default RE: 2 death 4 wounded in model airplane crash


ORIGINAL: David Gladwin

May I just ask how you arrive at the figure of 50 Gs, calculation, measurement or just a guess ! After all, to achieve 50gs on a 35 pound model means the wing needs to generate 1750 pounds. 3/4 of a ton, of lift without stalling or failing structurally. I have never worked with numbers such as 50 G and dont have the data on the BobCat aerofoil to do the maths (or better, have them done for me by an expert on these matters). Curious. I am not an engineer but I know that fatigue calculations on metal airframes are very well understood, those on composite structures much less so, perhaps we could have some professional input on this matter of cumulative fatigue on composites.


Regards,

David Gladwin.
David, The plane was traveling around 180 - 190 mph. The radius of the 90 deg turn to vertical was estimated by what people who witnessed it would have estimated, and it was around a 50' radius ( and this is one of the conservative estimates ) … these #s give you a figure of right around 50Gs … now, this would have been for no more than even a second, but exerted on the plane nonetheless … David, PM me or email me at [email protected] and we can discuss this some more, as I guess it has gone a bi off topic ..



Best regards,


Wojtek

Thread Tools
Search this Thread

Contact Us - Manage Preferences Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.