rear side vents

[podair]

Hi

my back seat passenger often complain they are freezing. It seems a lot of cold air is coming from the base of the rear seat on my 1967 M20F, just between the back of the back seats and the baggage area. There are two large rectangular vents there and as they are directed towards the baggage compartment I am not sure what their function is (there are little louvres on the side of the fuselage at that level, approx at the trailing edge of the wing). Is there any objection to blocking these with foam or something else?

actually looking at my parts manual, it says 'baggage compartment exhaust'....

[Piloto]

Those are exhaust vents. They need to be open to allow air flow in the cabin.

José

[Bob_Belville]

Try partially closing off the (large) heat outlets to the front seats (above the rudder pedals) with the heat full on to force more warm air to the rear outlets which are smaller than the front ones. 

[Shadrach]

 

Are the louvers bent?  These vents should be removing air from the cabin, not introducing it.  Our F is the same year as yours (they are clones save for the prop and the gear: S/N 670422). We have never had a heating issue; it's like a convection oven in there.  The center vent will really put out some heat and the forward facing foot well warmers will even keep my wife's Ice cub...er uh..I mean feet, warm.  something is not right with your system.

 

http://mooneyspace.com/gallery/image/30457-dirty-bird/

[Shadrach]

Try partially closing off the (large) heat outlets to the front seats (above the rudder pedals) with the heat full on to force more warm air to the rear outlets which are smaller than the front ones. 

 

 

 I think your system may differ Bob.  We have a small diameter, high velocity forward facing elbow that blows into the foot wells and then a large (about the size of my iphone) vent with controllable louvers on the center post (behind the J-Bar if you have one).

 

http://mooneyspace.com/gallery/image/36491-f-model-heat-ducts/

 

[jetdriven]

Leaking rudder pedal boots make a huge difference in cabin temp. Another is if the cowl flaps are open. On a J model at least, open cowl flaps kill the temperature

[Bob_Belville]

 

 I think your system may differ Bob.  We have a small diameter, high velocity forward facing elbow that blows into the foot wells and then a large (about the size of my iphone) vent with controllable louvers on the center post (behind the J-Bar if you have one).

 

 

 

 

Yes, mine is different. But is there a control to close off airflow to the front in order to increase airflow to the rear seats?

[podair]

Front seats are fine, the heating vent below the throttle is like a blast furnace, but little gets to back. basically I cook and they freeze.

there are small vents in the rear footwells but hardly any hot air is coming from that. there is definitely a big draft coming from the back of the rear seats.

[podair]

Looks like my setup is different as I have electric gear so there is a large fairing and a large heating vent. two little vents in the pilot and copilot footwells.

[Bob_Belville]

Front seats are fine, the heating vent below the throttle is like a blast furnace, but little gets to back. basically I cook and they freeze.

there are small vents in the rear footwells but hardly any hot air is coming from that. there is definitely a big draft coming from the back of the rear seats.

Yeah, what I'm saying is you need to throttle down the flow in the front so more flow will go to the rear. 

[Ratherbflying]

We've had the C for two winters now... Back seat passengers freeze to death. The panels that were supposed to cover the inspection ports that are under the back seat were missing. So while it is in for annual I cut some new panels and taped them down. Haven't gotten to fly her yet... Waiting for the EDM 900 to be installed before we button her back up and get in the air.

But I have to believe it's going to be warmer back there.

[TTaylor]

Backseat of our 1975 20F is cold no matter what we do. I have actually run a tube from the front heater vent to get hot air back to the rear seats. There have been several threads on this that may give a few options. It is amazing how the front seats can be too hot and back are freezing.

[Shadrach]

I think there are 2 issues at hand:

1) I think a lot of folks had the fiberglass insulation removed when SB2-208b was done, and did not replace it. I don't blame them for taking out the fiberglass, it's pretty nasty stuff and loses it's effectiveness with age (mice love it). However, the cabin does need to be insulated. We used a self adhering closed cell foam from Spruce.

2) The areas around the cabin structure incorporate the use of aluminum tape to seal the cabin. Over time, this tape becomes brittle and the adhesive fails allowing unwanted cold air to make its way into the cabin.

Unfortunately the tedious work of taping and insulating a cabin is not the kind of work that most A&Ps want to mess with (and many owners would not want to pay shop rates for it). It's a great project for an A&P supervised owner to complete and will help make for a more comfortable plane, if not a quieter one.

[Shadrach]

We've had the C for two winters now... Back seat passengers freeze to death. The panels that were supposed to cover the inspection ports that are under the back seat were missing. So while it is in for annual I cut some new panels and taped them down. Haven't gotten to fly her yet... Waiting for the EDM 900 to be installed before we button her back up and get in the air.

But I have to believe it's going to be warmer back there.

That looks great! It would be even better if it was insulated. I would consider a layer of non adhesive closed cell foam mat.

 

http://www.aircraftspruce.com/catalog/appages/supersoundproofsheet.php

[RobertGary1]

The tape under the rear seat does need to be replaced occasionally. Mooney recommends aluminum tape. Don't use duck tape as it will hold moisture against the panel. I found this helped with my passengers' "frozen butt cheek syndrome". Before that the kids were sitting on piles of blankets.

 

-Robert