Two small repairs -- suggestions?

[AndreiC]

Hello fellow Mooney owners,

I have two small-ish repairs I'd like to do to my '70E, which would fix non-airworthiness, but annoying issues. I need advice on how to proceed.

1) On takeoff, the ram air door opens a little bit, enough so that the warning light comes on while the gear is down. It is probably pushed inwards by the air pressure. I asked Mark at Top Gun in Stockton, about this, and he said that the problem is that the metal plate around the lever controlling the ram air is rounded out. (This is the thin aluminum plate that has the markings power boost/air vent; I attach a pic below.) He said in the original design you were supposed to first pull the ram air lever to the right past a notch, and then move it down in order to open ram air. The notch has been rounded out after 50 years. Do people have a suggestion how to address this? Can the metal plate be bought somewhere? (I am not sure if P/N 140049-034 is just the placard, or has the entire aluminum piece.)

2) The cold air lever in the panel does not work well (I am referring to the knob that you pull out, next to the hot air knob). When I open it, plenty of cold air comes in, but when I close it, the metal flap inside the air distributor only goes back in 3/4 of the way. Moreover, even if I push this metal plate down all the way by hand, it still lets a fair bit of cold air through. On a nice day this is only a minor nuisance (or none at all), but when it is cold outside I would like to limit the amount of cold air coming into the cabin. Is there a seal in the cold air distributor (the one on the passenger side, on the firewall, inside the cabin) that is shot? Or is there something else I should be looking at?

Thanks,

Andrei.

[Shadrach]

1)I don’t know what the metal plate you’re talking about looks like as the earlier birds like mine have a push/pull control with a button lock.  Good chance a machine shop could fabricate that part. Just need to remove it to have it reverse engineered. You definitely want filtered air during takeoff.

2) reads to me like your heating and ventilation system needs to be thoroughly inspected. The slider that you mentioned does not have a seal, but it should be fairly precise in its movement, and sit flush against the side of the mixing box. The cable and slider door should be lightly lubricated at annual.. if it’s not closing completely with the cable, someone needs to find out where it is binding.

[Echo]

Andre, I would put sponges in the ram air ducts during the winter.  This helped stop cold air coming into plane during the winter.  CB fix.

[M Terry]

in my f model I had a similar problem with the Ram air. Mine works by moving  the lever connected directly to the ram air "over center" so that outside pressure holds it closed rather than pushing it open. It may be as simple as loosening the nut on the end of the cable and moving it to where it goes over center when the control arm is moved to the closed position

[Shadrach]

10 hours ago, Echo said:

Andre, I would put sponges in the ram air ducts during the winter.  This helped stop cold air coming into plane during the winter.  CB fix.

Truth be told the heating and ventilation system is the one of the cheapest and most straight forward systems on the airframe. It requires so little that it is often neglected. 
Having a properly sorted HV system makes for much more pleasant all season experience.

[AndreiC]

On 3/22/2024 at 2:36 AM, M Terry said:

in my f model I had a similar problem with the Ram air. Mine works by moving  the lever connected directly to the ram air "over center" so that outside pressure holds it closed rather than pushing it open. It may be as simple as loosening the nut on the end of the cable and moving it to where it goes over center when the control arm is moved to the closed position

My E is same exact year model as your F, so maybe they use the same system. When you say "the nut at the end of the cable" do you mean at the cowling, or at the control arm end? I did not look at the mechanism closely... Thanks!

[Andy95W]

21 minutes ago, AndreiC said:

My E is same exact year model as your F, so maybe they use the same system. When you say "the nut at the end of the cable" do you mean at the cowling, or at the control arm end? I did not look at the mechanism closely... Thanks!

My biggest problem is usually the nut at the control knob end.

[Ragsf15e]

1 hour ago, Andy95W said:

My biggest problem is usually the nut at the control knob end.

Ha! I was going to say the opposite end.  Either way, having the over center work properly makes all the difference.  Mine required adjustment near the actual ram door and access was difficult but possible through the pilot side cowl.

[Ragsf15e]

On 3/22/2024 at 3:51 AM, Shadrach said:

Truth be told the heating and ventilation system is the one of the cheapest and most straight forward systems on the airframe. It requires so little that it is often neglected. 
Having a properly sorted HV system makes for much more pleasant all season experience.

I agree.  I was trying to think of a nice way to say that the air/heat system is already cheap and easy to maintain.  No need to go CB on it.  Also, while I don’t want to lose my CB card, I don’t like the idea of shoving sponges into air intakes…

[Echo]

6 minutes ago, Ragsf15e said:

I agree.  I was trying to think of a nice way to say that the air/heat system is already cheap and easy to maintain.  No need to go CB on it.  Also, while I don’t want to lose my CB card, I don’t like the idea of shoving sponges into air intakes…

Why not?  You still have overhead vent.  This worked great in the winter for me.  There was zero issue in removing them in the spring.  I had enough cold air coming throgh the eyeball at knee level that "the fix" was easy and expediant.  Cheap and easy are relative.  If there is a "danger from using a sponge" I am all ears...

[Hank]

3 hours ago, Ragsf15e said:

I don’t like the idea of shoving sponges into air intakes…

 

3 hours ago, Echo said:

Why not?  You still have overhead vent.  This worked great in the winter for me.  There was zero issue in removing them in the spring.  I had enough cold air coming throgh the eyeball at knee level that "the fix" was easy and expediant.  

This works well in colder parts of the country. Here in Sweet Home, such things aren’t necessary--if it's too cold, just wait a couple days. We had frost Monday and Tuesday mornings, and Wednesday and Thursday were near / over 80°.

[Ragsf15e]

37 minutes ago, Hank said:

 

This works well in colder parts of the country. Here in Sweet Home, such things aren’t necessary--if it's too cold, just wait a couple days. We had frost Monday and Tuesday mornings, and Wednesday and Thursday were near / over 80°.

I guess I just think adjusting the heat/cold system so it works is pretty much as easy as leaving it broke and shoving sponges instead.  I live somewhere real cold and I haven’t had an issue with too much cold or not enough heat.  

[Shadrach]

15 hours ago, Echo said:

Why not?  You still have overhead vent.  This worked great in the winter for me.  There was zero issue in removing them in the spring.  I had enough cold air coming throgh the eyeball at knee level that "the fix" was easy and expediant.  Cheap and easy are relative.  If there is a "danger from using a sponge" I am all ears...

It’s likely not a risk and presents a fine short term solution in a pinch. As a long term solution, it looks like needlessly deferred maintenance.  If a window regulator on my car fails, I’ll duct tape the window shut to keep the weather out until I can schedule the repair. I would not call it a permanent solution.

The HV system is well designed and when properly maintained, does not leak from either cold or hot side.  The Wemac vent (plum cooler) on the pilot side should not leak air either.

[M Terry]

On 3/24/2024 at 11:08 AM, AndreiC said:

My E is same exact year model as your F, so maybe they use the same system. When you say "the nut at the end of the cable" do you mean at the cowling, or at the control arm end? I did not look at the mechanism closely... Thanks!

at the cowl end.  An A&P had "repaired" it. but I found the nut just bouncing around in the cowling. It clamps on to the stiff piano wire that extends out of the cable housing. Mine does not have any type of locking mechanism in the cockpit. Other models have a locking mechanism at the handle rather than the over center mechanism in mine

 

[Shadrach]

20 hours ago, M Terry said:

at the cowl end.  An A&P had "repaired" it. but I found the nut just bouncing around in the cowling. It clamps on to the stiff piano wire that extends out of the cable housing. Mine does not have any type of locking mechanism in the cockpit. Other models have a locking mechanism at the handle rather than the over center mechanism in mine

 

Yes, I think the change happened in 69 or 70. Incidentally, the button lock version on my early F has required little more than lubricant and a new rubber seal every 8-10 years. I expect the cable will be due for replacement in the next 5 years.

[carusoam]

Cabin air has two types of systems… older is slide gates… newer is butterfly valves…

slide gates require a minimum of annual maintenance, to clean and lubricate…

butterfly valves are better, but use a rubber seal that needs a replacement every decade or three…

A damaged piece of rubber can easily get in the way of a proper seal.

 

ram air is similar, moving parts and rubber seal… but way more important to have operating correctly…   Any parts released by the ram air door are sent directly to the engine… no filtration in between.

 

inspecting the systems can be a bit challenging… depending on how much mechanical skills one has.

Always good to have a pair of manuals on hand… parts and service barely give enough information. But they are a great place to start…

may help to have a friend to operate the lever in the cabin, while the owner’s eyeballs are on the other end…  

Some of these systems have enough resistance to hold them in position.  It may be possible to clean and lubricate them so much, that they move on their own….

By the time an owner has gone through these efforts… it is an easy discussion with the mechanic to show them what is going on…

PP thoughts only, not a mechanic…

Best regards,

-a-