I did not forget, thus the discussion of damage from rocks, motors, batteries and mythbusters. The hardness matters little at these speeds. I just do not believe that a sUAV less than 5 pounds will stop a modern airliner engine. A bizjet or military jet, yes, but not a large airliner fanjet.

Sport_Pilot, would you not agree that a commerical regional jet like a CRJ 200 is roughly equivalent to a Gulfstream 650 business jet? There are thousands of them flying around at the airports most likely to be harrrassed by the irresponsible FPV pilot. Are you going to deny that a collision of one of these would cause potentially sever damage?

If something can stop or damage one type of engine it can certainly do the same to another type they all work on the same principle even if they are different sizes.

+10 anything besides air in and air out of a jet engine will create a certain demolition of that engine, frozen chickens or not.
1 drone with Lipo batteries weighing 4-5 lbs will certainly destroy that engine, fan blades and all. The result will be an engine shutdown, and a competent Airline Pilot will take immediate control and shut it down before it explodes and doe's damage to the airframe. I just don't get people talking about frozen chickens, or it's impact with a jet engine. If it's more than AIR IN and AIR OUT, there will be damage to any jet engine.

sport,
please post a reference to where you got the
sUAV 5 pounds or less idea.
the FAA considers sUAV to include even up to our 55 pound airframes.

and ya might want to take a 1800 to 2100 mah 3 cel lipo, a machete, and a hard stump and see just how a lipo reacts to being cut in two.
it is eye opening.

Sorry I didn't realise we were limiting this discussion only to drones weighing less than 5lbs. But if so I do agree the smaller the drone the less potential damage it might cause on impact.

Not sure if you fly drones or follow them but there are plenty of ready to fly units weighing more than 5lbs that anyone can buy and fly. e.g. DJI Inspire at 7lbs.

A quick search on YouTube will show you that plenty of people are building drones larger than 5lbs and flying them with no idea about airspace or flight paths.

Frozen chickens came up as an example after I stated hard metal objects would cause more damage to a jet engine than soft flesh. Sport claimed it made no difference and quoted the mythbusters experiment using frozen and thawed chickens.

I agree with you that any solid object hitting the fan blades at high speed can damage them. I still maintain the harder the substance ingested the more potential damage.

An example: Jet engines can ingest huge volumes of water without damage or flame out. Try putting that same volume of water through as large blocks of ice and it might be a different story.

Jet engines can ingest huge volumes of water without damage or flame out. Try putting that same volume of water through as large blocks of ice and it might be a different story
In the case of water, most of it gets slung outward by the fan blades and away from the central compressor and burner cans. What does get into the compressor basically evaporates and goes through without causing any problems due to the air heating up as the pressure increases

No, not at all.

They are different types of engines and built to different standards.

Large amounts of moderate sized hail can go in and out with no damage to the engines. Besides, I never claimed there would be no damage. Just that the engine would not quit when injesting a sUAV.

They do, and the hail they are required to ingest does damage, but the engines continue to run.

I disagree with that as well. Not that there are no idiots flying drones larger than 5 pounds, Just that there are very few.

But the water in liquid form doesn't damage the engine therefore the hardness does make a difference. Which was the whole point of our discussion.

:cool: Rob , My Friend , I really commend you for sticking to your guns and trying to get sport to see the truth in that , just about anything larger than a droplet of water really COULD cause problems . It been gone over several times here that it's no sure thing that a 5 pound object will destroy an engine , but that it's very highly likely . I've also previously stated that in my A&P training , we were shown films of the things that happen when even so much as a 5/8" box wrench goes down the pipe and I'm not willing to put sport's limited credentials over my FAA sanctioned training , no matter how many posts he makes in attempted defense of his flawed position .

Rob , I know you fly full scale .

I hold an (Inactive) FAA A&P mechanic's rating .

Exactly what ARE sport's credentials that the whole internet world should just say "oh sure , a 5 pound anything would be laughed off by an engine like a bug on the windshield"

NO way sport , ain't happening , Believe what you want to about this seemingly indestructable mythical turbine engine , but in the real world you'd likely be in a world of poop even with something as small as that little wrench .....

(inactive because if you don't use it for longer than two years , you got to go through a couple of FAA hoops to recertify . I spent a bit of time in a different industry than aviation before retirement )

Thanks for the comments Init and very helpful to have your input as an experienced FAA certified mechanic on this topic.

While I agree that modern engines are very reliable and may survive a small bird strike or some hail damage it seems like common sense to most that a hard metal object entering a spinning turbine is going to cause more serious damage.

As you rightly say, even something small can create big problems.

Does my 8.5 years in aviation, 3 working avionics on EA-6B Prowlers and the rest either working on Boeing commercial jets or instructing those that do, count for anything? I've seen several turbines destroyed by FOD and one person eaten head first, not a pleasant site seeing legs laying on the flight deck in front of a S-3A Viking's engine with the rest of him looking like hamburger behind it.

https://www.youtube.com/watch?v=_jfXX7qppbc

https://www.youtube.com/watch?v=0qpD6MDYEGY

https://www.youtube.com/watch?v=851y6F79Qtk

Check this out if you want to know the truth and what gets tested on jet engines for airliners and how the engine
stays running after ingesting birds, water and hail.

I wonder who really knows what they are talking about.

HYDRO: I disagree with your assumption. I worked on B-52D bombers in the Air Force as a Jet engine over two Aircraft Mechanic. We loaded the wings water tanks with 18,000 LBS. of Water. They water inject the J-57 engines with water which when mixed with air created more compression because the air is more dense. That produces more thrust.
When the Pilots turn on the injection systems, black smoke comes out the exhaust, which you can see for miles. I would tell you how much fuel they can carry but I won't because it may be a security issue with the Air Force if they ever found out. Let me please say it was liquid water, not 25 LB, blocks of ice, that's another story. I also worked on KC-135 Air tankers, but only in the support and recovery teams. I do know what I am talking about, I did it

Sounds like you are agreeing to me...

Mistaken post

Ya know something ? I just walked away from the computer but came right back because it just came to me , It's not inexperience nor hubris that's behind all these assertions of the turbine engine being 100% infallible , Nooo , I think it's the fear of the fact that somehow admitting a flight of birds or perhaps large hail COULD put the fire out will have them on edge any time they fly . They don't wan't to have the distrust that in the very rare chance , pray to God it ain't , but that it could be them , or me or you or anyone else , on their very next flight . Look no further than Captain Sullenberger and his display of proper airmanship once the fire went out cause the poop (:rolleyes:birds;)) literally hit the fan . I myself was amazed when my research turned up foreign object strike as the #1 cause of air fatalities , followed closely by human error . Outright mechanical failure not caused by external forces was so low it almost wasn't on the chart . But it was FOD , and most of that being Sully's birds , that have caused the most aviation trouble !

So again , YES , a model aircraft COULD cause problems for any full scale that hits it , and for this reason the model MUST be kept out of the full scale's path by the model's pilot responsibility . WE toy flyers have the duty to stay out of the way and not ever test whether a turbine would stay running after swallowing one of our toys . We already know birds CAN bring one down , that should be good enough knowledge that no one need test the theory with a model .....

LC: Hydro & FLAP happy:These baby's sure were on Water.
This is the first thing I say the day I arrived at K.I.Sawyer in May of '65 standing on the 2nd floor fire escape because a ORI had just started and they didn't have timeto process me in just then. I thought they were going to loose the last one from Wake Turbulence Then came the KC's man they had a ride.
OH LC: do U remember on those B-52 D's What the P&W J57's dash number was?

http://upload.wikimedia.org/wikipedi..._AFB_1986.JPEG

U are right The B-52 D had Turbo Jets not Turbo Fans witch would be even more Likely to flame out ingesting gobs of water
Engines: Eight Pratt & Whitney J57s of 12,100 lbs. thrust each <---Turbo Jets


B52 H the last dash has Turbo Fan Engines. And because they tell the Fuel Capacity of the H model (the only ones flying still Flying)
I'd guess it would be OK for U to tell the Fuel Capacity of the B-52 D model.

• Powerplant: 8 × Pratt & Whitney TF33-P-3/103 turbofans, 17,000 lbf (76 kN) each
• Fuel capacity: 47,975 U.S. gal (39,948 imp gal; 181,610 L)
  

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BOEING B-52D STRATOFORTRESS

Posted 11/17/2014 http://www.nationalmuseum.af.mil/sha...ransparent.gif Printable Fact Sheet
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After it became operational in 1955, the B-52 remained the main long-range heavy bomber of the U.S. Air Force during the Cold War, and it continues to be an important part of the USAF bomber force today. Nearly 750 were built before production ended in Oct. 26, 1962; 170 of these were B-52Ds.

Finally someone with some common since.

OH, and here. https://www.youtube.com/watch?v=851y6F79Qtk I'm just going to leave this here so that those
that do not think much damage can be caused..........

Water is not solid and thus has no hardness nor form, hail is solid and very large hail will do damage to the engine. I never said hardness doesn't matter, just that electric motors (of small sUAV) are not hard enough nor large enough to do enough damage to stop the engine.