High Alt = Cold in my Bravo

[irishpilot]

I've been doing some long-haul high alt flights (FL160-FL200) and it gets cold. I've noticed that with all my vent levers closed there is still cold air blowing from the vent underneath the front coffee cup holders. If I turn on the heat, it comes out lukewarm from that same vent. It's cold enough to require a sweater with hoodie.

 

Below 15k, the heater is fine. Questions are:

 

1. is the center console vent always on?

2. Any tricks to help button up the cabin to keep warm air in better?

 

Fly Safe,

Safety Forum Mod

 

 

[exM20K]

contact Mooney customer support or any good MSC.  There is an approved procedure to close off some of the holes in the heater box on the firewall.  I did this in my Acclaim, and it made a huge improvement.

-dan

[donkaye]

9 minutes ago, irishpilot said:

 

I've been doing some long-haul high alt flights (FL160-FL200) and it gets cold. I've noticed that with all my vent levers closed there is still cold air blowing from the vent underneath the front coffee cup holders. If I turn on the heat, it comes out lukewarm from that same vent. It's cold enough to require a sweater with hoodie.

 

Below 15k, the heater is fine. Questions are:

 

1. is the center console vent always on?

2. Any tricks to help button up the cabin to keep warm air in better?

 

Fly Safe,

Safety Forum Mod

 

 

 

I've never had any issue with the heat on my M20M or any other M20M I have flown.  Make sure the cabin heat control is fully out and the cabin vent control is fully in.  If you're not getting adequate heat there may be something wrong with the shroud and that should be checked.

[PDXBravo]

I've had a similar experience and have posted about the same:

In my experience, when the OAT gets colder -30C, the heater struggles to keep temps in the cabin warm.  I wear a warm jacket and winter cap when I anticipate flying in these colder temps.  I'm also looking in to a portable heater to plug in to the 12v to help boost cabin temps.  

[jlunseth]

Well, it sounds from your description as though the problem is really that the cabin vent is not fully closing, resulting in cold air being mixed in with your heat.  In my aircraft (231) that is adjustable I am pretty sure.  I think I had my A & P look at it years ago.  That is the first thing I would look at, make sure the vent fully closes.  The heat is also adjustable, you could have that adjusted up. Maybe the last guy was warm blooded and needed all that cold air.

[Davidv]

5 hours ago, donkaye said:

I've never had any issue with the heat on my M20M or any other M20M I have flown.  Make sure the cabin heat control is fully out and the cabin vent control is fully in.  If you're not getting adequate heat there may be something wrong with the shroud and that should be checked.

Me neither, in fact, I've never pulled the cabin heat more than about a half inch open otherwise it gets too hot.  I usually crack it, wait for it to heat up, then close it.  I would take the advice of some of the others above since it seems you have some sort of leak.

[irishpilot]

thanks for the responses. I double-checked the vent controls and they are fully seating. I will have my A&P look at the fresh air vent. It sounds like that needs adjusting.

Fly Safe,
Safety Forum Mod

[carusoam]

+1 on Dan’s description of engineered holes in the air vent system... continuously allowing air flow when closed...

 

there have been updates to the system closing some of the holes...

 

check with Mooney docs before making any mods...

use a CO monitor too...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Bravoman]

21 hours ago, donkaye said:

I've never had any issue with the heat on my M20M or any other M20M I have flown.  Make sure the cabin heat control is fully out and the cabin vent control is fully in.  If you're not getting adequate heat there may be something wrong with the shroud and that should be checked.

Not on topic but I noticed your submission to IFR magazine in the latest issue. Your panel looks great!

[LANCECASPER]

We need to see the panel

[donkaye]

7 minutes ago, Bravoman said:

Not on topic but I noticed your submission to IFR magazine in the latest issue. Your panel looks great!

I hadn't had the chance to read that issue yet, so was surprised when you mentioned it.  Thanks for calling my attention to it.

[donkaye]

1 hour ago, LANCECASPER said:

We need to see the panel

I've posted it a number of times on MooneySpace, but here it is again in flight.  It is a dream panel.  The addition of the GFC 500 was the icing on the cake.  The autopilot holds altitude based on the G5.  As you can see, it is perfect.  Change the Baro setting and the airplane corrects altitude automatically.  Enroute VNAV is magical, once you figure it out.  I love the YD.  This panel confirms the benefits of using one manufacturer when possible for interface simplicity.  The EIS system wasn't available when I did  the upgrade, however, due to the additional capability of the MVP 50 and the additional screen real estate gained,  I would have chosen it anyway.  Luckily the WX 500 did easily interface, as did the Shadin used as a backup for fuel management.  I added the GCU 485 a month before the GFC 500 was certified for the Bravo.  It is used mostly for Baro setting only now.  Had I known the certification of the GFC 500 was a month away, it would not have been necessary. With the latest system update to the G500TXi you can change the display aspect ratios between the PFD and MFD on the fly, which I find very useful if I want a better look at the MFD..

[mike_elliott]

did you get your autopilot issues fixed, Don?

 

[donkaye]

19 minutes ago, mike_elliott said:

did you get your autopilot issues fixed, Don?

 

The answer, "For the most part".  I'd really like to fly another M20M that has added the GFC 500.  Only two things could be better.  In turns where the bank angle goes to 30° (the maximum allowed on the GFC 500) there is some damped oscillation that diminishes after a couple of oscillations.  It's acceptable.  Also, on approach, there is some oscillation on the glide path that is also acceptable.  I did fly Adam Fineberg's (201Mooniac) J model that exhibited none of these issues.  It was perfect.  So, from my perspective, the J is perfect, the M almost.

[kmyfm20s]

I have never had a problem with heat. No matter how high or cold out it will blow hot air for me. I have the opposite problem that the blowing vent air in the summer time is diluting my A/C making it harder to cool the cabin. I did improve my door seals which helped a lot. I could hold a pierce of paper and it would suck right up to the door before. This would suck out cold or hot air. I want to find out more about the vent hole closures. 

[DavidB]

Brother Carl's answer:

It will always be cold in the climb. The heat comes when you level off and lean the engine back. This heats up the exhaust pipes and  with the larger air volume flow (from increased airspeed) you can get plenty of heat. I've flown the Bravo at 20K with OATs of -12C (+10F). This is with center Heat full open and center Air full closed. Naturally you also have to close off the overheads (front and back) and the two side blasters on the side walls. I usually wear a long sleeved shirt with a t-shirt and light jacket. No need for hood or gloves. I've spend a ton of time at 17.5K both summer and winter. When I had my 1981 K model Mooney (with the Merlin wastegate), I had many trips at 27K and it's always cold that high. The Lycoming turbo in the Bravo isn't that robust so I usually stay below 18K unless I really need to go higher.

[carusoam]

So little heat when you don’t have a muffler...

you get choices... muffler or turbo?

during the climb, the EGT is being kept controlled going deep ROP...

you get more choices... good TIT in the climb or heat?

PP’s chilly thoughts, not a Turbo driver...

Best regards,

-a-

[irishpilot]

I'm going to fly high again tomorrow. I have a feeling my fresh air vent isn't fully closing.

Fly Safe,
Safety Forum Mod

[JohnB]

On 10/11/2019 at 12:38 AM, DavidB said:

Brother Carl's answer:

It will always be cold in the climb. The heat comes when you level off and lean the engine back. This heats up the exhaust pipes and  with the larger air volume flow (from increased airspeed) you can get plenty of heat. I've flown the Bravo at 20K with OATs of -12C (+10F).

That is interesting, I'll have to see if that's the same on mine next high flight. What I do is if I know im going to go high, I turn on the heater at a low altitude before it gets chilly and just leave it on, so when I get up to altitude its already comfy. Yes all vents, side and overhead vents need to be closed which takes an effort to remember to close all of them. I also noticed that I was getting some air into my door seals, so I installed inflatable door seals which Im not sure you can get anymore which helped dramatically with noise but also kept it warmer on going higher.

[irishpilot]

I flew at FL190 this morning. the fresh air vent isn't fully closing. will have my A&P adjust.

Fly Safe,
Safety Forum Mod

[Tony Armour]

On 10/11/2019 at 3:46 AM, carusoam said:

So little heat when you don’t have a muffler...

you get choices... muffler or turbo?

during the climb, the EGT is being kept controlled going deep ROP...

you get more choices... good TIT in the climb or heat?

PP’s chilly thoughts, not a Turbo driver...

Best regards,

-a-

Except the Bravo does have a muffler and a turbo ;-)

 

[Tony Armour]

18 hours ago, irishpilot said:

I flew at FL190 this morning. the fresh air vent isn't fully closing. will have my A&P adjust.

Fly Safe,
Safety Forum Mod
 

The fresh air on a Bravo is designed to flow some air 100% of the time. It’s been some years but I “think”* it may come from factory holes in the door that opens and closes. It’s designed to do that. Could that be changed, yes, would I do that....very carefully......maybe just make the holes smaller, less of a leak. That said, in cruise if you are dressed comfortably for a 65 degree day the heat should be more than adequate. If I have ever kept the heat wide open I don’t remember but it’s possible I guess. I don’t have a lot of flights at 23k, 24k in the past few years. My flights are typically 14k to 16k now days.

*I believe back in the day I pulled the hose off because I thought the door wasn’t closing all the way. Not for lack of heat really but did not want the door operating incorrectly.