Cold Breeze in Cabin

[takair]

Every winter I've noticed a cool breeze on the back of my head that feels as though it is coming from behind me.  The heater is putting out plenty of heat from under the panel, actually makes your legs and lower body uncomfortably warm while the back of your head and neck are cold.  the back heat vents in front of the back seats, floor level, do not put out much heat.  I've tried plugging the vent in the hat rack area.  The gaspers all seal well and the air does not seem to come from the gap between the interior panel and spar.  Basically, I can't figure out where the air is moving from.  Is it simply the thin windows transferring cold?  Anybody have this issue in an older bird?  The 64 had crude heat outlets, but I'm not sure that is the problem.  Maybe I need to take someone along to sit in back and figure it out, but perhaps someone has ideas.  Was not as big a problem living in Georgia, but between Northeast Winter and hair loss, it's time to track it down.

[Yetti]

There are big vents to the outside in the back of my plane at about rear seat level.

[takair]

1 hour ago, Yetti said:

There are big vents to the outside in the back of my plane at about rear seat level.

I've seen those on other aircraft, but mine does not have them.

[carusoam]

My C leaked from the overhead vents. 201er's nanook style hat was stylin', and functional.

I don't know how to seal the vent from the outside.  The inside was a piece of plastic rotated generally over the holes.

I bet there is a rubber seal in there that is 40plus years old..?

Best regards,

-a-

[takair]

8 minutes ago, carusoam said:

My C leaked from the overhead vents. 201er's nanook style hat was stylin', and functional.

I don't know how to seal the vent from the outside.  The inside was a piece of plastic rotated generally over the holes.

I bet there is a rubber seal in there that is 40plus years old..?

Best regards,

-a-

Good thought, but mine actually has metal gaspers, like an airliner.  They seal really well....no air coming in there.  It really is odd....as the air feels like it is moving forward at head level.  

[Piloto]

Just get the hood on. It works all the time.

José

[Marauder]

Good thought, but mine actually has metal gaspers, like an airliner.  They seal really well....no air coming in there.  It really is odd....as the air feels like it is moving forward at head level.  

Check the door seals Rob. Especially the front edge of the main cabin door.

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[tigers2007]

Mine has a very loud hiss - that might explain my less than 32F cabin temp.

Is it possible to just seal the vent off for the winter? I taped up mine on my C150 and it was quite effective. Used clear packaging tape.


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[takair]

5 hours ago, Marauder said:

Check the door seals Rob. Especially the front edge of the main cabin door.

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I did the door seals a couple of years ago and can't feel air coming in there.  I also did the baggage, but can't be sure that I don't have a problem there...now that I think about it...  Will have to figure out some way to check that in flight.  The vents are all tight, from what I can tell.  This air moves forward, which is the really odd part.  I suppose it could simply be circulation caused by the heated air coming in the front and this is the cold air being displaced.  Doesn't sound like anybody else is experiencing quite the same thing, in other words, nobody has said "they all do that"...so there is still hope of finding this.

[Yooper Rocketman]

Living in the U.P. and dealing with more nasty winters than I care to admit with GA airplanes, I can give you a few tips.

Most vent systems "pressurize" the entire overhead, so closing the interior air vents only stops the air from flowing from the vent.  It will still force it's way out of every crack and gap.   In both Mooney's I've owned and both organizationally owned Bonanza's I've flown for Northwoods Airlifeline, I have "closed cell" plugs I install in the outside vent openings during the winter.  I may have the description wrong on the "closed cell" foam, but I'm using the foam the is usually more rigid than seat foam, and seems to have a "waterproof" type nature to it.  A lot of more valuable items shipped by UPS or FedEx (like aircraft instruments, etc.) use this foam as it holds shape pretty well but still will bend or compress with enough force.  I cut this foam into "right sized" fillers, sometimes needing two to fill the vent opening completely and keeping the slip stream profile as friendly as possible.  Here is an example of the product I use. http://www.packnetltd.com/industrial-packaging/foam-packaging/?gclid=CNbgss2f9tACFZ26wAodRPIHFA  (in the pictures look at the white one, third from the left). I never purchase the stuff, I just spot it once in a while in shipping boxes and save larger pieces to cut my plugs from.

The back side of your luggage area is NOT insulated.  I have a several specially cut pieces of 1" Styrofoam for this area.  One is cut and fit against the lower back wall of the compartment.  A second one is cut and fit against the upper back wall (back of the hat rack).  The last one fits the floor of the hat rack.  Now these are not "approved aircraft materials" so, I am essentially "carrying" these pieces as "cargo"  .  You could do the floor of the luggage area too, but I find the carpet moderates some of the cold already.

You mention your heater gets hot enough already, but I have found some pretty significant leaks in the heater control boxes in the engine compartment (most times an easy fix with some caulk or silicone).  I have also been surprised on some of the holes and sealing of wires and control cables coming through the firewall.  Every place you can stop cold air penetration will impact the overall cabin temp.

While we are at it, how's your oil temp doing.  I need to block off half the oil cooler in the winter on my Rocket to keep oil temps in an approved temp range.  I do that with a small piece of rubber floor mat, cut to fit nicely over half the oil cooler.

Hope this is of some value.

Tom Sullivan

 

 

[DXB]

Yooper is on the right track I suspect.  I have the identical problem. My heater really puts out. If I run it at full blast, I will sit there sweating, wearing a hat, and wondering why the back of my head is still freezing cold, 

[TTaylor]

There are many threads on the subject.  I often use a tube from the front heater vent to the back seats for winter flights to put the heat in the back. I can do this with an electric gear, still possible with J bar but has to be moved for take off and landing.  I replaced the wind lacing on the door and bagage compartment and that helped but in general the back on Mooney's are much colder than the front.

[Bart Chilcott]

I've noticed this in my 65 E. Mine isn't an issue but occasionally, during temps less than 30 F, its as if a very very light cold draft hits the back of my neck.  My rear heat outlets work great and I've never had a rear passenger complain of being cold.  On the contrary, they usually ask me to turn the heat down.  But still, I can feel it like a very light draft.  I always suspected it was air being forced in small openings and being forced to the rear of the plane by the front heat vents. 

[Oscar Avalle]

I had a similar problem and was able to resolve by replacing the fiberglass insulation with a newer kind of insulation. I also replaced the door seal and the baggage door seal. Both things helped significantly.


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[Bennett]

Suggestion: On the J and the 261 I had LASAR install a passive pin for the upper section / front of the door. When adjusted properly, the door is held tightly against the door frame. This keeps a tight seal to eliminate wind noise and drafts from that area.


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[Marauder]

Suggestion: On the J and the 261 I had LASAR install a passive pin for the upper section / front of the door. When adjusted properly, the door is held tightly against the door frame. This keeps a tight seal to eliminate wind noise and drafts from that area.


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You have more details on this mod? Interested in learning more.


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[mooniac15u]

I had a similar problem in my M20D.  With just the heater it got hot up front and I could reach back with my hand and feel the temperature gradient.  Resealing the door helped a lot.  I also found that adding some vent along with the heat helped circulate the air better because the vent air had a lot more velocity.  The trick is finding the right mix.

[mooniac15u]

16 hours ago, tigers2007 said:

Mine has a very loud hiss - that might explain my less than 32F cabin temp.

Is it possible to just seal the vent off for the winter? I taped up mine on my C150 and it was quite effective. Used clear packaging tape.


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The pilot side window window can sometimes cause a hiss if the seal is going bad.  Next time you are flying try pushing on the window and see if the hiss changes.

[Bennett]

You have more details on this mod? Interested in learning more.


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The pins were, as I understand it, developed originally for Bonanzas. The doors were being sucked outwards at high speed. I saw these pins a long time ago at Oshkosh, and again, as I understand it, the STC was expanded to Mooneys. I will take a couple of photos the next time I am in my hangar. I know other Mooney pilots who have added the pin with the same success. You might check with Dan or Paul at LASAR for more details.

[Bob_Belville]

47 minutes ago, Bennett said:

The pins were, as I understand it, developed originally for Bonanzas. The doors were being sucked outwards at high speed. I saw these pins a long time ago at Oshkosh, and again, as I understand it, the STC was expanded to Mooneys. I will take a couple of photos the next time I am in my hangar. I know other Mooney pilots who have added the pin with the same success. You might check with Dan or Paul at LASAR for more details.

Paul is recuperating from recent heart surgery...

[Yooper Rocketman]

I needed to install the foam fillers on the Bonanza today for a flight tonight so took pictures of them while installing in my Mooney.  You can see some minor damage to my front vent fillers from using a screwdriver to remove them every spring (fit very tight, but work great).

Tom Sullivan

 

 

[Hank]

5 hours ago, Bennett said:

Suggestion: On the J and the 261 I had LASAR install a passive pin for the upper section / front of the door. When adjusted properly, the door is held tightly against the door frame. This keeps a tight seal to eliminate wind noise and drafts from that area.


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I've heard of that. Just make sure an experienced person does the drilling. If they're off just a little but, it won't work,and there's no "do over" drilling into the door frame . . . .

[Bennett]

Paul is recuperating from recent heart surgery...

Thanks for the heads up. I spoke to the folks at LASAR. Paul had triple bypass heart surgery, and is said to be doing well. Sherry is with him. I wish him well.


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[Hank]

3 hours ago, mooniac15u said:

The pilot side window window can sometimes cause a hiss if the seal is going bad.  Next time you are flying try pushing on the window and see if the hiss changes.

I opened my window in to flight for the first time Saturday, to get good reflection-free photos. When I went to close it, it sucked out of my hand and slammed pretty hard.

[Guest]

In many cases the sealant is missing from the cable pass through in the rear bulkhead beside the battery box in the tail section.  It appears to be some sort of plasticine.

Clarence