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-   -   How much damage? (https://www.rcuniverse.com/forum/ama-discussions-74/11613276-how-much-damage.html)

Sport_Pilot 04-01-2015 08:49 AM


A small screw or nut can destroy turbine engine.
Yes it can and very likely on a bizjet or military aircraft, but airliner engines are designed and tested to withstand 5 pound birds at them, and hale the size of baseballs. So your warning is valid.

phlpsfrnk 04-01-2015 08:50 AM


Originally Posted by ramboamt (Post 12014651)
Yes this is a good video of what happens when a foreign object is ingested into a jet engine. Did you noticed the, at the end of the video, sailor sitting to the left of the other sailors had only bandages and all of his appendages, the engine was "FOD" by his head set i.e. plastic and steel and some small rubber bits, and his body blocking the air flow into the inlet causing a compressor stall, the flames out the tail pipe. This goes to show that Plastic, Steel and Rubber can destroy an engine.

Also keep in mind that being hooked to the catapult the A6 was probably at ground idle at the time.

Frank

Sport_Pilot 04-01-2015 11:50 AM


Originally Posted by phlpsfrnk (Post 12014678)
Also keep in mind that being hooked to the catapult the A6 was probably at ground idle at the time.

Frank

They are at full throttle well before the catapult is launched.

I-fly-any-and-all 04-01-2015 12:12 PM

catastrophic failure seems most likely but lets see a demonstration video of a jet turbine inhaling a quad copter!!!

Bozarth 04-01-2015 12:23 PM

Polls like this are junk. Let's take a poll - guess how many pebbles I have in my hand. Junk.

Kurt

mackeyjones 04-01-2015 01:47 PM

My Question is why is it a risk that some people seem willing to take, I am pretty sure most people have enough commonsense to not want to be the first person responsible for taking down an aircraft with a quad.

littlecrankshaf 04-01-2015 06:02 PM


Originally Posted by FMRR (Post 12014674)
Gentleman, I am only posting a comment because I have seen this question a few times now. So I hope I am perfectly clear. A small screw or nut can destroy turbine engine. You are putting the flight crew and passengers in extreme jeopardy. I am beside myself why anybody would think it's ok to fly anything in the flight path of a passenger or miltary aircraft. .

You are certainly right...but a flock of birds can too... Fortunately I have never known of anyone purposely trying to fly a model in the path of full scale. We sometimes forget one of the biggest reasons there are so few aircraft incidents...the vastness of airspace is the single biggest reason. As humans we can see and avoid fairly well while flying our toys. Unfortunately there are a few idiots of late that seem to minimize that advantage by flying when and how they shouldn't. They, individually are the problem...not you or me, I suspect.

Sport_Pilot 04-01-2015 11:22 PM

I agree, what people think and what the facts are, are often two different things. Even scientists and doctors are often wrong because of this. I was watching a show on PBS last night on the history of cancer cure, and originally doctors thought cancer spread radially from a tumor. Not until the 50's or 60's did they learn that the cancer was already spread through the body through the lymph and blood stream before the turmor was found. A poll of doctors at the time would have been opposite the facts.

phlpsfrnk 04-02-2015 02:05 AM


Originally Posted by Sport_Pilot (Post 12014760)
They are at full throttle well before the catapult is launched.

True, but it was certainly not at full throttle when the crew is preparing the plane for launch which is what the film was showing when the crewman caused the FODD of the port engine.

Frank
(SCPO (E8) USN Retired)

Sport_Pilot 04-02-2015 02:48 AM

Your video states he was sucked in when the engine was throttled up, but did not say how much power it was producing. He was not pulled through that was his helmet and other cloths that went through. Here is a video with the whole story.

http://www.poetv.com/video.php?vid=41479


True, but it was certainly not at full throttle when the crew is preparing the plane for launch which is what the film was showing when the crewman caused the FODD of the port engine.
The crew was not preparing it at the time, the crew had just left from preparing and the pilot given the signal to throttle up, the person training the crew stepped foward to inspect the work and was sucked in. Per the video above the engine was not at full power, but was likely at or near full thottle.

init4fun 04-02-2015 03:48 AM


Originally Posted by Sport_Pilot (Post 12014672)
Softness doesn't matter, a pound of mud in a bag would do as much damage as a pound of lead, maybe more because it is larger. At high velocity mass matters most, it's like jumping in a lake of water from a tall bridge, it will kill you just as fast as jumping on a concrete road.


:cool: Hi Sport ,

Your quite right about that , and for those who think different , I'll relate this ;

In Massachusetts , our biggest airport is Boston's Logan airport . Over the years , we've been darned lucky that we have had very few aircraft incidents . One that all in this thread should know about happened in 1960 and was (I'm pretty sure) the worst crash ever at our airfield (as to lives lost) . An aircraft (Lockheed L-188 Electra) had just taken off and flew through a flock of the tiny little birds called "Starlings" . Tiny little birds , starlings are , but a whole flock of em was all it took to stop the engines and cause a crash ! With much loss of life (62 dead / 10 survivors) . To the dead and grieving , it mattered not that it was several hundred 3oz birds instead of just a few Canada Geese , the end result was the same .

So to those who poo poo the notion of something as small as a quad causing any major damage I say , just look at the history of Eastern Airlines flight 375 on Oct 4 1960 , brought down by nothing more than a flock of 3oz birds ! Now , with the metal involved in brushless outrunners , I really doubt it would take anywhere near a whole flock of quads to inflict major damage to an aircraft's engine ......

Sport_Pilot 04-02-2015 04:30 AM

A whole flock of 3 ounce birds could be well over 20 pounds of birds and if we are talking about a 20 pound ARF it would most likely take out the engine, but the OP said a 2 pound ARF and your example does nothing to prove that a 2 pound ARF will take out an airliner. See the link below for bird strike certification.

http://www.skybrary.aero/index.php/A...rd_Strike_Risk

Note that it is a single 8 lb bird or a small turkey or large goose. Or for small birds 16, 2 pound birds. Hundreds of starlings are more than 16 pounds. Yes a 2 pound quad could take out an airliner engine, but not likely. This is fact, not an opinion poll.

phlpsfrnk 04-02-2015 05:35 AM


Originally Posted by Sport_Pilot (Post 12015131)
Your video states he was sucked in when the engine was throttled up, but did not say how much power it was producing. He was not pulled through that was his helmet and other cloths that went through. Here is a video with the whole story.

http://www.poetv.com/video.php?vid=41479



The crew was not preparing it at the time, the crew had just left from preparing and the pilot given the signal to throttle up, the person training the crew stepped foward to inspect the work and was sucked in. Per the video above the engine was not at full power, but was likely at or near full thottle.

Okay sport, I'll grant you what it said in the video however it also stated at 5:24 "since the engine was slow" but I'll concede the videos statements about Mil power. Please note the hand positions of the plane director in the moments before the FODD and then his cut engine signal. That said from my personal observations while aboard the Roosevelt the application of Mil power does not occur till some moments after the hookup and launch does not occur till everyone is clear and signals the plane director that they are clear.

Frank

mattster1971 04-02-2015 06:54 AM

Just restrict use around airports and restrict heights in other areas, its easy. Now to just stop your neighbor who is filming you through your bedroom window in the morning as you get dressed. That is the craft you should be more worried about.

Sport_Pilot 04-02-2015 06:57 AM


Originally Posted by phlpsfrnk (Post 12015185)
Okay sport, I'll grant you what it said in the video however it also stated at 5:24 "since the engine was slow" but I'll concede the videos statements about Mil power. Please note the hand positions of the plane director in the moments before the FODD and then his cut engine signal. That said from my personal observations while aboard the Roosevelt the application of Mil power does not occur till some moments after the hookup and launch does not occur till everyone is clear and signals the plane director that they are clear.

Frank

I gathered that the power was applied just before he stepped foward and the engine had just started to accelerate, but not near full speed yet.

littlecrankshaf 04-02-2015 07:00 AM


Originally Posted by mattster1971 (Post 12015229)
Just restrict use around airports and restrict heights in other areas, its easy. Now to just stop your neighbor who is filming you through your bedroom window in the morning as you get dressed. That is the craft you should be more worried about.

Are you an FAA employee???

ahicks 04-02-2015 07:10 AM

There are certain basic truths. Regarding this topic, or any topic associated with model aircraft of any type operated in the proximity of full scale traffic - that truth?

You can't fix stupid.

Trying to educate people with the mental awareness of an 8 year old? Not going to happen.....

f16man 04-02-2015 07:45 AM

Any thing that is ingested into a jet compressor fan will damage it as they are made of titainium not high carbon steel made for cutting metal, bird bones, quad copters, helmets, screws, nuts, or any thing else that could bang around and cause breakage or unbalance of the turbine,,, if you think that's not true see what GE or R R would suggest weather to just let her rip or tear down after an ingestion of any kind..................

ramboamt 04-02-2015 11:03 AM

From Wikipedia about bird strikes:
The point of impact is usually any forward-facing edge of the vehicle such as a wing leading edge, nose cone, jet engine cowling or engine inlet.
Jet engine ingestion is extremely serious due to the rotation speed of the engine fan and engine design. As the bird strikes a fan blade, that blade can be displaced into another blade and so forth, causing a cascading failure. Jet engines are particularly vulnerable during the takeoff phase when the engine is turning at a very high speed and the plane is at a low altitude where birds are more commonly found.
The force of the impact on an aircraft depends on the weight of the animal and the speed difference and direction at the impact. The energy of the impact increases with the square of the speed difference. Hence a low-speed impact of a small bird on a car windshield causes relatively little damage. High speed impacts, as with jet aircraft, can cause considerable damage and even catastrophic failure to the vehicle. The energy of a 5 kg (11 lb) bird moving at a relative velocity of 275 km/h (171 mph) approximately equals the energy of a 100 kg (220 lb) weight dropped from a height of 15 metres (49 ft).[SUP][9][/SUP] However, according to the FAA only 15% of strikes (ICAO 11%) actually result in damage to the aircraft.

f16man 04-02-2015 11:56 AM


Originally Posted by ramboamt (Post 12015372)
From Wikipedia about bird strikes:
The point of impact is usually any forward-facing edge of the vehicle such as a wing leading edge, nose cone, jet engine cowling or engine inlet.
Jet engine ingestion is extremely serious due to the rotation speed of the engine fan and engine design. As the bird strikes a fan blade, that blade can be displaced into another blade and so forth, causing a cascading failure. Jet engines are particularly vulnerable during the takeoff phase when the engine is turning at a very high speed and the plane is at a low altitude where birds are more commonly found.
The force of the impact on an aircraft depends on the weight of the animal and the speed difference and direction at the impact. The energy of the impact increases with the square of the speed difference. Hence a low-speed impact of a small bird on a car windshield causes relatively little damage. High speed impacts, as with jet aircraft, can cause considerable damage and even catastrophic failure to the vehicle. The energy of a 5 kg (11 lb) bird moving at a relative velocity of 275 km/h (171 mph) approximately equals the energy of a 100 kg (220 lb) weight dropped from a height of 15 metres (49 ft).[SUP][9][/SUP] However, according to the FAA only 15% of strikes (ICAO 11%) actually result in damage to the aircraft.

We are still comparing meat and hollow bones to motors batteries and radio gear , all the math calcs and scientific bull will never convince me a quad would not damage a jet engine, ,I know I would not like to be a passenger on that plane.........

vertical grimmace 04-02-2015 12:10 PM

Not to mention when the Lipos vent out. The whole aircraft would explode! : )

Sport_Pilot 04-02-2015 03:13 PM


all the math calcs and scientific bull will never convince me a quad would not damage a jet engine
It would cause damage, but if only a two pound quad the engine would most likely keep running. The hardness of the material almost doesn't matter at these speeds. Also the engines can take very significant hail damage and ice is hard.

edh13 04-02-2015 03:23 PM

Predicting FOD damage in an engine is like trying to guess where the pachinko ball is going to land. Throw the same bolt in the same engine a dozen times and your results will be anything from one chipped blade to a “corn cobb’d” compressor section. I’d be just as worried about the quad hitting the windscreen.


I’ve seen a couple threads about ‘what could possibly happen’ if a small quad hit a plane. As if there is an acceptable risk!!??
THERE ISN’T

vertical grimmace 04-02-2015 03:30 PM

The question is, "What will happen to a quad operator who hits a full scale aircraft?" That is the question.

THERCAV8R 04-02-2015 08:26 PM

It doesn't Matter. Stay Away from the big Stuff!!!!


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