Cabin vent scoop

[rbridges]

my VOR antennas are in my wing tips.

[TheTurtle]

Just found my vent will close with the knob but will only open a 1/4" and thats only sometimes.  If I set it to Open and then pull the vent by hand it opens.   Cant tell if the knob is slipping on the shaft or what.  Been lubing it the last few days to see if it will break free.  May take the knob off and see whats in there this week.

[MARZ]

On 8/14/2016 at 7:18 PM, cnoe said:

Here's what the knob mechanism looks like above the headliner. Quite simple.

It's for sale on Ebay. Been there quite a while.

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A simple device - yes

Damn near impossible to get to for cable replacement - absolutely

Plan on the better part of a day if the cable is broken if not lube generously 

[HRM]

On August 14, 2016 at 7:03 PM, Yetti said:

I have to look at it to see which way is open.

LOL. BTDT (Been there, do that).

[jetdriven]

2 hours ago, TheTurtle said:

Just found my vent will close with the knob but will only open a 1/4" and thats only sometimes.  If I set it to Open and then pull the vent by hand it opens.   Cant tell if the knob is slipping on the shaft or what.  Been lubing it the last few days to see if it will break free.  May take the knob off and see whats in there this week.

It's a standard 1/4"shaft radio knob.  It's easy for that set screw to strip out in the plastic knob.  But you can source another knob off eBay easily.  Some call them amplifier knobs.  

[TTaylor]

Just now, jetdriven said:

It's a standard 1/4"shaft radio knob.  It's easy for that set screw to strip out in the plastic knob.  But you can source another knob off eBay easily.  Some call them amplifier knobs.  

Actually the 75 has an aluminum knob about 1.5" in diameter.  The usual problems in the system are the cable getting rusty, the inner cable getting kinked, the gears needing lucubration, and a broken or pulled loose inner steel cable.  The only thing that makes it difficult is you must disassemble much of the airplane to get to it and then still work through very small openings.

[bjoseph604]

On August 14, 2016 at 11:46 PM, jetdriven said:

Just eliminate the scoop.  It's quieter and flows more air. This is a 1977 airplane. 

BTW I love that paint job.  Very nice

[dougm]

I've got a 63 C model.   The cable going to the overhead scoop is broken.  Is there anyway, short of pulling the entire head liner out, to replace this cable?

hope hope hope hope

Using high speed aeronautical tape to hole it open for now. 

Doug

[Bob_Belville]

6 minutes ago, dougm said:

I've got a 63 C model.   The cable going to the overhead scoop is broken.  Is there anyway, short of pulling the entire head liner out, to replace this cable?

hope hope hope hope

Doug

Not in a '66E. But there's not that much holding it up and if you haven't had the headliner down in years you probably ought to do it. In addition to replacing that cable you probably will put fresh tape on the whole vent plenum and confirm that the drain line from the vent is connected and not plugged up.

Again, I'm familiar with a '66 and it's possible your '63 is different. 

[dougm]

Thanks

I guess I'll have to dig in.  Looks like a headache job just for a vent.  But you're right.  Needs to be checked anyway.

[jamesm]

Hi Byron,

How did you  make NACA air  scoop/vent in the dorsal fin area ?

Did you  have to fabricate the NACA scoop vent ?  (you did real nice job)

Do you recall the skin thickness  for the patch over  the original scoop above the main cabin  vent?

Did you see a speed increase in your cruise  speed  when you  from the original vent location to dorsal vent location ?

What is diameter tube/duct from  NACA scoop to cabin vents ?

Is there a main shut off going to the  NACA scoop vent ? or  does each vent shut off the vent ?

Did you have to fabricate a manifold for the  new vent location ?

By chance do you have pictures of  NACA air scoop and manifold ?

 

Thanks,

James '67C

 

[jetdriven]

20 minutes ago, jamesm said:

Hi Byron,

How did you  make NACA air  scoop/vent in the dorsal fin area ?

whole dorsal fin came from a crashed plane. It has the NACA scoop molded in. I got the entire kit from the same crashed plane as a matter of fact.

Did you  have to fabricate the NACA scoop vent ?  (you did real nice job)

Do you recall the skin thickness  for the patch over  the original scoop above the main cabin  vent?

.032" aluminum 2024 flush patch  

Did you see a speed increase in your cruise  speed  when you  from the original vent location to dorsal vent location ?

a knit or two but not a huge difference. However it's much quieter and flows a heckuva lot more air  

What is diameter tube/duct from  NACA scoop to cabin vents ?

around 2.5"

Is there a main shut off going to the  NACA scoop vent ? or  does each vent shut off the vent ?

yes to both  

Did you have to fabricate a manifold for the  new vent location ?

came from th crashed plane  it's a aluminum box that goes from the single 2.5" aluminum tube in the tail to the 4 smaller hoses . It bolts to the back of the hat shelf  

By chance do you have pictures of  NACA air scoop and manifold ?

send me your email address in my feed or send me an email it's in my profile I'll seems you some stuff 

 

Thanks,

James '67C

 

 

[HRM]

On August 25, 2016 at 7:29 PM, jamesm said:

How did you  make NACA air  scoop/vent in the dorsal fin area ?

You can buy them pre-made. The operative question is: how did it get approved to be on there?

I'd like to know what the logbook entry looks like.

Not to cause trouble, but if that was an unapproved mod, and a serious mod (close to the empennage), and then you take it off a crashed aircraft and put it on yours...wow!

That all said, being in the Republic of Burning Hot Summers I wouldn't mind letting the hangar elves do it to my E.

[Hank]

Harley, if I remember, he took the parts from a later J and put them into his early J. Kind of like another member swapped out much if the cabin interior from a later J into an early one because he really, really hated the throttle quadrant and wanted the push/twist controls instead.

It's still not easy, though.

[jetdriven]

It says basically " removed entire fresh air system from m20J s/n 24-0160. Closed up roof scoop hole. Removed complete and entire fresh air sysyem from 24-1085 and installed in this plane.  Minor alteration using factory parts, if it's even that. It's all factory parts  

The dorsal fin looked pretty good to me and it was undamaged.  I did add some glass to the flange so i could countersink it and install flush rivets. I hate dome rivets and scalloped fiberglass flanges.  I like them flat and tight. 

Edited August 27, 2016 by jetdriven

[Bob_Belville]

Byron, I suppose that the NACA scoop has less drag than the roof scoop when the latter is open but how would they compare when the movable scoop is closed?  

[HRM]

14 hours ago, jetdriven said:

It's all factory parts

Thanks, that says it all. The fact that the factory was doing this is a plus for those of us sweltering in the Tejas heat as that location is golden.

[jetdriven]

Here's where the scoop used to be. 

[HRM]

13 hours ago, jetdriven said:

Here's where the scoop used to be. 

Sooooo smooth 

[ArtVandelay]

Here's where the scoop used to be

I notice you have 2 GPS? antennas off center and right next to each other, never seen that before.

[rbridges]

I like the air scoop in front of the tail.  Looks more integrated and less like an afterthough.

[jetdriven]

9 hours ago, teejayevans said:

I notice you have 2 GPS? antennas off center and right next to each other, never seen that before.

One is for the KLN-89B and one is the external antenna for the Aera 500.  

[mike20papa]

Byron's attention to detail and his working to fit components to exacting tolerances .. well, you have to see it to believe it.  Great looking Mooney!  Joe

[KSMooniac]

14 hours ago, jetdriven said: It's all factory parts

Thanks, that says it all. The fact that the factory was doing this is a plus for those of us sweltering in the Tejas heat as that location is golden.

I hope to do the same sometime in the next year...it is a far superior system compared to the pop up scoop. Easy, paperwork-wise, to go from a later J to an early J. Might require a 337 to retrofit on a pre-J, but I can't imagine any FSDO denying such a mod since Mooney parts are used and it doesn't affect structure, controls, etc. You can also bury an ELT antenna under the fiberglass dorsal fin.

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[Stetson20]

On August 15, 2016 at 8:50 AM, cnoe said:

... and I want to replicate his blade VOR antenna and clean up the mess on my vertical stab. Getting rid of my towel bar and old whisker mounts ought to be worth about 15 knots (that's 1.5 actual knots and 13.5 "visual " knots).

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Ahh.. So that's how Matt comes up with his estimates on speed increases.