UAV weight is not important

[coafin]

There must be some weight to increase inertial moments and reduce side wind effects, but if this weight is water packed in rubber bags, it is not dangerous to other planes or people.

I think FAA has not understood that.

Hardness vs. softness is also more important than mass.

What is needed, are impact tests to crash test dummies. UAV is like a car, and military UAV replaces binoculars and mountains, not aeroplanes.

[djklein21]

At 600 mph water=concrete

[kd7ost]

There must be some weight to increase inertial moments and reduce side wind effects, but if this weight is water packed in rubber bags, it is not dangerous to other planes or people.


Not fully true. Inertia is inertia and mass is mass. People jump off bridges and get killed when they hit the water. If the molecular density at speed cannot be as fluid as a gas, it will cause damage.

Dan

[Unterhausen]

There was a recent incident where a streamer and locking pin from the landing gear on an F22 was sucked into one of the engines, and caused $6 million in damage. In case people are not familiar with these locking pins, they are a few inches long and weigh a few ounces. If that had been an F16 in flight that had sucked up the equivalent weight uav, there would be a smoking hole somewhere.
If an airplane runs into a 5000 lb bag of water that is magically suspended in mid-air, the people in that airplane are going to be wishing they knew how to maintain altitude by flapping their arms. But that really isn't the point. Weight does matter, and the lower the weight of the uav, the less likely it is that there will be any one item that's capable of doing damage to an airplane with people in it.

[coafin]

There was a recent incident where a streamer and locking pin from the landing gear on an F22 was sucked into one of the engines, and caused $6 million in damage.

I remember the times, when a boat crashed to swimmer, and sunk.

Since then (3000 years ago) boats are built TO LAST small objects. Nowadays there is even a double hull, or double bottom. :D

What is a value of F22 or F16 during war time, if some kids can drop them easily and cheaply, with their toys ? Zero ? Or even negative, because pilot, fuel, cargo and lot of money is lost also.

[sodman12]

What is a value of F22 or F16 during war time, if some kids can drop them easily and cheaply, with their toys ? Zero ? Or even negative, because pilot, fuel, cargo and lot of money is lost also.
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umm because this is highly unlikely

[Tuner]

In essense their does not exist and unless it is like a large insect their will most likely be no UAV's that would be safe for a commercial airliner anytime in the next 10 years.

Even a small .09 or .049 engine at 400-500mph would slice right through a commercial airliners aluminum skin. IMO at least. Look what frigen Foam did to the shuttle. (yah dont get technicall on that)

In the end I think it is not unreasonable to request that ALL uav's have a system that can identify obstacles and avoid them most specifically other aircraft.
Easy NO! Neccessary Maybe not now? Neccessary for large scale deployment of commercial UAV's Definately.
The risk is low right now when the odds of a UAV and airplane being in the same airspace are very low but a collision has already happened with the border patrol using UAV's just recently if Im remembering the article properly. I live in AZ and we get occational news on the border patrol front.

Scott

Scott

[coafin]

In essense their does not exist and unless it is like a large insect their will most likely be no UAV's that would be safe for a commercial airliner anytime in the next 10 years.

Even a small .09 or .049 engine at 400-500mph would slice right through a commercial airliners aluminum skin. IMO at least. Look what frigen Foam did to the shuttle. (yah dont get technicall on that)

In the end I think it is not unreasonable to request that ALL uav's have a system that can identify obstacles and avoid them most specifically other aircraft.
Easy NO! Neccessary Maybe not now? Neccessary for large scale deployment of commercial UAV's Definately.
The risk is low right now when the odds of a UAV and airplane being in the same airspace are very low but a collision has already happened with the border patrol using UAV's just recently if Im remembering the article properly. I live in AZ and we get occational news on the border patrol front.

Scott

Scott

Maybe there are no birds in Arizona, because you havent heard of them. All cheap UAV's are lighter than them. But that is not the point. The point is that UAV mass distribution and hardness can be better than birds has. Thats why I hope crash tests should be the only valid test method.

Lets cut the crap about size, height and mass. Crash tests ! Crash tests ! I dont have problems with them, even to jet engine or 1000mph wind shield.

B2 and Mig-29 (top) are UAV-compatible. Maybe Mig-21 also. Nothing can go in.

[coafin]

. People jump off bridges and get killed when they hit the water. .

Dan

I was not talking about surface tension. It has no effect here. I can put some drops of shampoo to water-stabilator if you like.

[Tuner]

Good point in the end its all about what really happens in real world tests.

[Myron]

Hey Guys,

Interesting topic... There is a company out there that is currently doing and has done studies on "environmental impact" of all classes (size,weight,mass, inertia, ect.) of UAV's. All of the data is going directly to the FAA to help them and a few other groups right the regulations for all classes of UAV's in the NAS..
One would think that a bird has no effect on full scale aircraft but it does. I think most of us have all seen the video of the bird getting sucked into the intake of the military trainer and the subsequent crash of the aircraft. The FAA has a huge task in making everyone happy when it comes to UAV use in the NAS...

[LukeZ]

This might be just a slight bit off topic, but an economist might say the one that comes from a risk-adjusted collision. In other words, a collision might cause damage equal to 1 million dollars, but if the risk of it happening is 1 in 1 billion, the actual risk-adjusted cost would be less than one cent. Of course there is a social value placed on the hundreds of lives in an airliner that might exceed the ability to measure. But it seems to me that, in addition to the excellent suggestion for impact tests, it would also be wise to calculate the probability of impact.

Art Vanden Berg has a very interesting little spiel about the risks of collision on his high-altitude glider page here (http://www.members.shaw.ca/sonde/risks.htm). He points to the hundreds of radiosondes launched every day in Northern America, with never a recorded collision with an aircraft. He also references this very interesting MIT study done in 2003 (http://icat-server.mit.edu/Library/Download/205_Weibel%20R%20-%20Safety%20Considera.pdf), which he summarizes thusly:For very small UAVs (5kg or less), as long as it keeps clear of major airports by 7-10 nm, and below 10,000 feet in altitude, the risk was found to be on the order of 1 collision per 1 billion UAV flight hours.
In other words, this might imply that given some common-sense safeguards (don't fly near an airport, stay below some acceptable altitude), and a small enough size, the FAA would not be unreasonable in allowing largely unfettered access by UAVs to the NAS.


Luke

[sodman12]

Hey Guys,

One would think that a bird has no effect on full scale aircraft but it does. I think most of us have all seen the video of the bird getting sucked into the intake of the military trainer and the subsequent crash of the aircraft. The FAA has a huge task in making everyone happy when it comes to UAV use in the NAS...


airliners with jet engines are build to take a hit from a large flying bird. plus all have 2 engines

[kd7ost]

I was not talking about surface tension. It has no effect here. I can put some drops of shampoo to water-stabilator if you like.

Surface tension has no effect here you say?
How bizarre.

The space shuttle burned up in the upper atmosphere. It wasn't even in enough atmospheric density to sustain human life. How do you explain that surface tension? Water is a lot thicker and speed to mass matters. I don't care how much shampoo you put in it. In fact, a water balloon full of shampoo or water mixed with shampoo would most likely kill someone if it hit them in the head at 200 + mph. Of course if you have a 747 flying along at 20 mph and it hits a water balloon with shampoo coming at it at 10 mph, you'll probably be OK. :D

Dan

[Hovertime]

Whats more dangerous to the shuttle entering atmosphere - 5kg of frozen water floating in the upper ozone layers, 5kg of melted lead suspended there by fishing line, or 5 pounds of compressed fur held there by magic?

Hope UAV forum wont get infested by certain disease... :rolleyes:

[clolson]

I can transport double my capacity/weight of UAV's if I keep at least 1/2 of them flying at any given time.

[Unterhausen]

all cockpits and jet engines are bird strike tested. They will all fail at a certain weight bird, it's not possible with today's technology to change that. The "birds" used for the testing is a gelatin slug, so they are nowhere near as hard as a glow engine.

[kd7ost]

all cockpits and jet engines are bird strike tested. They will all fail at a certain weight bird, it's not possible with today's technology to change that. The "birds" used for the testing is a gelatin slug, so they are nowhere near as hard as a glow engine.

I think what we're all jabbing at is this blanket statement.

There must be some weight to increase inertial moments and reduce side wind effects, but if this weight is water packed in rubber bags, it is not dangerous to other planes or people.

It's quite a broad stroke. Even if there is some validity to it given certain conditions, it's fundamentally an incorrect statement at face value. It might be fun to have a serious conversation about it though.

I'll start off

coafin,

What kind of plane are you thinking of where the water bags help increase inertial moments and reduce effects of side winds? What are the water bags made of and how big? What shape? Inside the fuselage or outside hanging in the breeze? I would argue that only small and quite momentary side winds could be dampened this way. That's kind of rare I think when we talk about winds. Harder winds would still cause the plane to move sideways. It just moves at a slower rate. But, once that mass is in motion, it takes longer to stop it and return it to its original course. (All of Newtons Laws apply) It dampens slower under pilot control when there is no wind. It will make the plane more sluggish to react to control input. I'm not saying that's always a bad thing at some level, but there might be other ways to reduce effect of cross winds without increasing inertia (weight and mass) of a flying object. Generally speaking, more mass can cause harder impacts resulting in greater damage. That’s something we all understand.

Dan

[coafin]

Surface tension has no effect here you say?
How bizarre.

The space shuttle burned up in the upper atmosphere. It wasn't even in enough atmospheric density to sustain human life. How do you explain that surface tension? Water is a lot thicker and speed to mass matters.
Dan

I havent made any tests or simulations, but I think, the mass -that is needed to increase moment of inertia- can be soft and distributed. Water in many small bags.

Then collision (once in 100 years) is like flying in rain.
In the long run, I hope air intakes will be better located, like B2 has. Not because of UAVs, but birds and hailstorms. They are a threat.

[coafin]

I think what we're all jabbing at is this blanket statement.



It's quite a broad stroke. Even if there is some validity to it given certain conditions, it's fundamentally an incorrect statement at face value. It might be fun to have a serious conversation about it though.

I'll start off

coafin,

What kind of plane are you thinking of where the water bags help increase inertial moments and reduce effects of side winds? What are the water bags made of and how big? What shape? Inside the fuselage or outside hanging in the breeze? I would argue that only small and quite momentary side winds could be dampened this way. That's kind of rare I think when we talk about winds. Harder winds would still cause the plane to move sideways. It just moves at a slower rate. But, once that mass is in motion, it takes longer to stop it and return it to its original course. (All of Newtons Laws apply) It dampens slower under pilot control when there is no wind. It will make the plane more sluggish to react to control input. I'm not saying that's always a bad thing at some level, but there might be other ways to reduce effect of cross winds without increasing inertia (weight and mass) of a flying object. Generally speaking, more mass can cause harder impacts resulting in greater damage. That’s something we all understand.

Dan

I was thinking side wind bursts, that shake video. Video quality and speed is a safety issue also. In fact, maximum speed and angular speed should be limited automatically if radio or video quality is having problems like noise or lag.

[Myron]

So lets say you have an "un-important" 3lb UAV operating in a combat zone with many UH-60s, Jetrangers and MD500's and all the other birds Uncle Sam uses. Lets say the the military bird is zipping along outbound at 100 Mph with 10 marines on mounted up. Lets say that a 3 lb UAV is inbound at 40 mph and you have a windscreen
impact.. Thats a 140mph impact with 3lbs... Its GOING THROUGH the windscreen!!!
Being a member of the SC203 and the ASTM(along with some others here) the UAV weight IS AN ISSUE... You can try to mask impact data and theory all you want.. its simple physics.. The motor and battery will rip through the windscreen(unless it is bullet proof) and create havoc for the poor guy flying the bird... How in the world can you make a statement that weight is not important?

Myron

[coafin]

How in the world can you make a statement that weight is not important?

Myron

The main idea is :

-not 1 heavy engine, but 3-5 lighter distributed
-not 1 heavy battery, but 6 smaller cells around

Usually only one part can hit to windscreen or jet intake. In this model, it is safer. Maybe not enough, but to the threat level similar to birds.

Crash test includes everything, mass, hardness and mass distribution.

[TMorita]

The main idea is :

-not 1 heavy engine, but 3-5 lighter distributed
-not 1 heavy battery, but 6 smaller cells around

Usually only one part can hit to windscreen or jet intake. In this model, it is safer. Maybe not enough, but to the threat level similar to birds.

Crash test includes everything, mass, hardness and mass distribution.

Just rip the bring into it.

Toshi

[avianaut]

There is work being done around the world to enable safe UAV operations in commercial airspace. Technical, and operational, solutions are being developed and will probably both be employed. UAV manufacturers and operators, and regulatory authorities et al are all working together to make it happen. It's expected to take years, but it will happen. Eventually UAV's will operate seamlessly and safely within the airspace system, possibly the only way you'll know it's unmanned is there'll be a notation on the flight plan. I don't believe there will ever be crash tests to determine if a UAV could, or not, bring down another plane ( I find that quite amusing!).

I've seen a surgical glove half full of liquid water smash the windscreen of a minibus at about 20mph. I've repaired birdstrike and hail damage on fast jets and airliners. Yes, even small soft things can do a lot of damage.

Cheers.

[Dog8]

This hole thread is a bit bizarre.