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My m20F used to have a turbo, but has been returned to stock with overhauled engine.  The Ram air was deleted along the way and all cables and hole are gone.  It cruises at 140 Kts at 4 or 5k feet at about 9gph.  On takeoff it has about 28"MP when ambient is 29.  I am a student and have been as high as 10500, but i didnt take down cruise numbers.  

Ive been thinking of removing scoop and possibly installing challenger filter, i hate the oil that comes off the brackett filter!

Are these cruise numbers about usual?  Do you think this scoop causes more drag than benefit?  It just uses the screws from filter to hold it on.  

20171105_182728.jpg

Edited by Grandmas Flying Couch
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Now that you have made it public you have this mod, you might be better taking it off unless you have a field approval for it. I dont see where it increases the wetted area much, and probably would help get air into the low pressure area intake. Good move on getting rid of the Brakett, they are messy and that stuff gets into your servo.

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6 hours ago, mike_elliott said:

Now that you have made it public you have this mod, you might be better taking it off unless you have a field approval for it. I dont see where it increases the wetted area much, and probably would help get air into the low pressure area intake. Good move on getting rid of the Brakett, they are messy and that stuff gets into your servo.

Anybody on the ramp can see that it's there.  I didn't put it there, so I'm not too worried about it.  If I got into a crash, I doubt that would be the cause.

5 hours ago, Yetti said:

Funny enough my Mooney specific A&P said to change to a Brackett Filter

 

5 hours ago, Hank said:

I've heard enough about the filters, both good and bad, that I've not changed mine, either. My last A&P also advised keeping the Brackett, so I have. It's simple to maintain.

I don't know what to make of it.  I would use a Donaldson, but they don't make one of the curved ones for the M20F, E.  So I guess it's the bracket, it's only $10-15 a filter cartridge.  That goop is nasty though.  I live in a dusty environment so I need good filtration, I've read the K&N lets more through.  

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12 hours ago, Grandmas Flying Couch said:

Anybody on the ramp can see that it's there.  I didn't put it there, so I'm not too worried about it.

There is a story of plane being grounded for less here, and its' owner also didn't do it. You could undoubtedly build a good case of why you shouldn't be fined, have your licenses suspended etc., but then again, why go thru it when you are questioning the validity of the mod anyway. It only takes one FAA compliance guy who believes the FAA's role is as an enforcement agency vs. a regulatory agency to make your day and weeks thereafter a bit of a pear shaped mess. Do they read this list? Call me paranoid, I think they do. If you don't have a 337 for it, you might consider getting one or remove it to make your plane legal.

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12 hours ago, Grandmas Flying Couch said:

Anybody on the ramp can see that it's there.  I didn't put it there, so I'm not too worried about it.  If I got into a crash, I doubt that would be the cause.

Good luck telling the FAA that, they could care less who put it there. You have something unapproved sticking off the nose of your aircraft. It is you as the owner/operator who has final responsibility for this stuff. I suggest listening to Mike and removing it or getting a field approval (highly unlikely).

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Before Corvalis and Columbia, the airplanes were called Lanceairs.  They were certificated, and were an alternative to Cirrus for those who do't like auto interiors or parachutes.  Really nice machines, especially of the day.  Driven out of business by the worst bad luck I think I've seen in aviation not involving loss of life or limb.

I heard second hand about a fellow who shaved down a seat cushion in his Lanceair.  He was a tall fellow who hit his head on the ceiling of the cockpit, so he shaved down some of the padding in the seat cushions to give his head a bit more room.  Some FAA guy saw it, grounded the plane and made him put the full on cushion back.

The only reason I would think of to leave the nonconforming item on my aircraft is what I'll have to pay to fix it is the same whether or not the FAA tells me to do it.  Perhaps the FAA will never see it, and I can keep flying it forever.  The one down side to this argument is if someone from the FAA does see it and grounds your aircraft, they may do so at a time you really want to fly it.

And yes, the OPs F is slow.  My C goes about as fast.  

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I don't care to play armchair lawyer on the internets, so to answer OP's original question and get back on topic:

You will lose 1" MP through the intake system. So that's about right where it should be. The challenger system is just a re-branded K&N automotive filer with the applicable 200% airplane tax. Yes they do flow more air, however, they also have a much worse filtration ratio. One of the lowest in the industry. I have a K&N on my truck, and on a dyno  I gained absolutely nothing. The filter is not the restriction in the autotmotive intake, the lower intake system is. On an airplane, it might be different, but for $235 versus $10....that's ~24 filters (about 1200 hours) before the Challenger pays for itself. Even then, you won't get the gain of simply reinstalling your ram air. Also, 140KTAS at 4k sounds normal. You don't see better TAS unless you get high. At 8-10k I get 147KTAS in my C model. You should be equal or faster. Go fly high and double check. If not, I doubt its a power problem, its probably a rigging problem. And yes, I'd remove the scoop. It looks like its only adding drag.

kn-v-oem-1.jpg

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I'd take that off right away. If it's not in the logs then I'd toss it and move on. If it is, have someone make log entry for removal of unapproved scoop.  Then again maybe it needs an entry anyway, I don't know.  My IA would not approve as airworthy at annual inspection. 

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4 hours ago, mike_elliott said:

There is a story of plane being grounded for less here, and its' owner also didn't do it. You could undoubtedly build a good case of why you shouldn't be fined, have your licenses suspended etc., but then again, why go thru it when you are questioning the validity of the mod anyway. It only takes one FAA compliance guy who believes the FAA's role is as an enforcement agency vs. a regulatory agency to make your day and weeks thereafter a bit of a pear shaped mess. Do they read this list? Call me paranoid, I think they do. If you don't have a 337 for it, you might consider getting one or remove it to make your plane legal.

I'll take it off, I'm headed out there to remove a broken zerk on the gear and grease the gear.  I guess it's not worth the trouble.  I didn't think the FAA was going around that much.  It may even be in the log books, but I think it's causing more drag than not.  So I'll ditch it.  

 

2 hours ago, Raptor05121 said:

I don't care to play armchair lawyer on the internets, so to answer OP's original question and get back on topic:

You will lose 1" MP through the intake system. So that's about right where it should be. The challenger system is just a re-branded K&N automotive filer with the applicable 200% airplane tax. Yes they do flow more air, however, they also have a much worse filtration ratio. One of the lowest in the industry. I have a K&N on my truck, and on a dyno  I gained absolutely nothing. The filter is not the restriction in the autotmotive intake, the lower intake system is. On an airplane, it might be different, but for $235 versus $10....that's ~24 filters (about 1200 hours) before the Challenger pays for itself. Even then, you won't get the gain of simply reinstalling your ram air. Also, 140KTAS at 4k sounds normal. You don't see better TAS unless you get high. At 8-10k I get 147KTAS in my C model. You should be equal or faster. Go fly high and double check. If not, I doubt its a power problem, its probably a rigging problem. And yes, I'd remove the scoop. It looks like its only adding drag.

kn-v-oem-1.jpg

Thanks, Raptor, I've followed your continuous thread about your "D"!  I wen't through a dozen squawks and 6 months before I could fly, I would clutch my pillow and read your thread late at night for inspiration LOL!  I too found a MX that will work with some owner assisted stuff.  I will get rid of the scoop and stick with the brackett.  My brackett filter has gotten really dirty in 40 hours so it must be working!  I fly in the desert so dirt is a major concern.  I feel like if an FAA inspector came up to me about the scoop I would grab the drill pull the five screws hand him the scoop and reinstall screws.  I'm reasonable, don't know if the FAA is.  

Edited by Grandmas Flying Couch
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I would be curious about your manifold pressure.  See if you can fly it the same day you take it off and then after.  You should be able to do it in almost the same air.  I would think that would help.  You could get reasoning for a field approval if it does make a difference.

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29 minutes ago, Grandmas Flying Couch said:

I'll take it off, I'm headed out there to remove a broken zerk on the gear and grease the gear.  I guess it's not worth the trouble.  I didn't think the FAA was going around that much.  It may even be in the log books, but I think it's causing more drag than not.  So I'll ditch it.  

 

Thanks, Raptor, I've followed your continuous thread about your "D"!  I wen't through a dozen squawks and 6 months before I could fly, I would clutch my pillow and read your thread late at night for inspiration LOL!  I too found a MX that will work with some owner assisted stuff.  I will get rid of the scoop and stick with the brackett.  My brackett filter has gotten really dirty in 40 hours so it must be working!  I fly in the desert so dirt is a major concern.  I feel like if an FAA inspector came up to me about the scoop I would grab the drill pull the five screws hand him the scoop and reinstall screws.  I'm reasonable, don't know if the FAA is.  

You're welcome and thanks for following. If you are flying in the desert, it makes for good reason for oil analysis', watch the silica levels. You might need to change the air filters sooner. Even a little dirt will wear an engine out quick

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I've seen additional scoops on the oil cooler but never the intake scoop.

With the prior turbo system installed- I'm surprised that the system needed it. Turbos don't or shouldn't care too much about intake air losses, as they can suck more air than is pushed thru them. 

I'd ditch it for the reasons posted in prior posts.

-Matt

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  • 3 weeks later...

I tried a K&N and found that the "fuzz" wears off in a year or two on my D model. Lots of "holes" in the filter when it does that. Went back to Brackett. I too live in a dusty area and sometimes need to change the foam filler twice a year (cheap). I get most of my dirt on it from wind blowing across the ramp. 

Quick question- If the F came with a ram air system hows does it qualify as returned to factory type certified design without the ram air system?

Is that an approved removal modification? I don't know, never done it. And, I don't think 1 Fed in a thousand would even know it wasn't there.

And yes, some Feds do walk around looking at airplanes. Its called ramp checks and they can look even if you're not around and they can hand a "do not fly" tag on it! 

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14 minutes ago, cliffy said:

And yes, some Feds do walk around looking at airplanes. Its called ramp checks and they can look even if you're not around and they can hand a "do not fly" tag on it! 

Interesting concept. Has anyone here ever gone out to the airport and found a "do not fly" tag on his plane? The lawyer in me is interested in the legalities of this situation.

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We have a member on here that found one on his airplane. I don't remember the outcome but it was a lot of grounding stuff they wrote up. There was a long thread on it a year or two ago. One item they found was "dents" in the wing. 

The Feds have to do so many  "ramp inspections" per year, or so I understand. 

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17 minutes ago, cliffy said:

We have a member on here that found one on his airplane. I don't remember the outcome but it was a lot of grounding stuff they wrote up. There was a long thread on it a year or two ago. One item they found was "dents" in the wing. 

The Feds have to do so many  "ramp inspections" per year, or so I understand. 

Now that you mention it; seems like I remember reading about that.

I wonder if their "do not fly" tag enumerates the deficiencies. If so, could the owner's A&P look at those items, make a determination it was airworthy and allow the owner to ignore the tag? Would it take an IA? I suppose if the owner disagreed with the tag, he could fly it off and wait for an enforcement action!       Interesting.  

Of course, the smart way would be to call the FAA guy and talk to him about what was wrong and see if you could solve the problem.

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An interesting item about IAs is that they don't have the power and can't just wave a magic wand and declare something "airworthy". They can only declare it airworthy because it matches some kind of approved data that makes the issue "airworthy". 

Lets take dents for instance. Did the airplane come with dents from the factory? No? Then its not airworthy if it has dents UNLESS there is an approved manual (data) that gives sizes, shapes and location of "approved" dents. All large airline equipment has such a manual, our small airplanes rarely do. Therefore, if you have dents in the wing of your Mooney, and the Feds drop a tag on it, the IA can't just say its of no consequence and sign it off. If the structures manual has dent limits then the IA can refer to that section and sign it off if it meets limits. Hail damage and hangar rash comes to mind here. 

When an IA signs off a "Major Repair"  on a 337 he must show reference to some kind of approved data like 43.13 section, chapter and verse, STC, etc. He can't just say it looks "airworthy".  Likewise, when the Feds write up "corrosion found on the flap" the IA can't just say it is "airworthy" because its not too big. If its not in the book, it has to be fixed according to the book. 

Now, one can always try for a "ferry" permit to get the airplane to another airport for the work to be done but the Feds may not approve that either depending on how much they wrote up. 

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1 hour ago, DonMuncy said:

Interesting concept. Has anyone here ever gone out to the airport and found a "do not fly" tag on his plane? The lawyer in me is interested in the legalities of this situation.

I 'owned' a Cherokee 140 before this. My uncle stopped flying it years before, so it was derelict on the ramp. Just another ramp queen like most airports. The FAA came by one day and wrote me a letter saying they inspected it and determined it to be in an unairworthy state, for better or less. I threw it in the trash, the plane wasn't ever going to fly again, sold it for scrap months later.

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I believe the situation with the dents can be resolved by hiring a structural DER. I believe his opinion has to be accepted. From what I understand the airlines have structural DERs on staff for situations that are not in the books. The engineer will analyze the damage and design an acceptable repair for the damage.

Edited by N201MKTurbo
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Usually they send the info to Boeing and they detail the allowable limits and the repetitive inspection times and if the part has to be replaced in the future. For example only a .015” dent is allowed on the leading edge of a 737NG tail. 

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Had many dents detailed in the structure manual on many Boeings over the years, especially near the doors where the equipment went BANG!

Yes to the DER as the commentary was for the IA to refer to "something" of an "approved" nature for the IA to sign off and not just wave a magic wand and say it was airworthy.

Now can anyone tell me why the 737 has no deicing on the tail?  :-)  Just a little drift but an interesting story. 

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