Open doghouse mod

[AJ88V]

When I was shopping, I saw an E model that had the doghouse reconfigured so that the top was removed and rubber seals extended to the underside of the cowling.  Owner/A&P had done it and it looked a lot less complicated than my enclosed doghouse.

Anybody know about this mod?

[47U]

12 minutes ago, AJ88V said:

Anybody know about this mod?

Not really a mod.  As near as I can tell, when the E was introduced in 1964 it had the doghouse.  When the F came along in 1967, it had an open baffle system.  The E adopted the open baffle in 1968.  The C/G had the doghouse throughout their production runs.

I’m sure there are some C/G’s out there with an open baffle, either through a cowling STC or field approval, but there are complications to be solved when going down that road.  If @Sabremech has a moment perhaps he can share a thought.

[DXB]

24 minutes ago, 47U said:

Not really a mod.  As near as I can tell, when the E was introduced in 1964 it had the doghouse.  When the F came along in 1967, it had an open baffle system.  The E adopted the open baffle in 1968.  The C/G had the doghouse throughout their production runs.

I’m sure there are some C/G’s out there with an open baffle, either through a cowling STC or field approval, but there are complications to be solved when going down that road.  If @Sabremech has a moment perhaps he can share a thought.

Sure would like to know if there's a easy way to convert the C to open baffle and if there's any cooling improvement - the C with the doghouse is a piece of dogsh*t for cooling, and it also makes maintenance access harder.  That said, I'm not sure why Mooney converted the E to open baffle in '68 and left the doghouse in place on the C until the bitter end in ~77 (?).  Key differences with the E/F include the C's oil cooler location on the left front of the cowl and of the carb heat air intake in the back top right of the doghouse. 

[Shadrach]

1 hour ago, DXB said:

Sure would like to know if there's a easy way to convert the C to open baffle and if there's any cooling improvement - the C with the doghouse is a piece of dogsh*t for cooling, and it also makes maintenance access harder.  That said, I'm not sure why Mooney converted the E to open baffle in '68 and left the doghouse in place on the C until the bitter end in ~77 (?).  Key differences with the E/F include the C's oil cooler location on the left front of the cowl and of the carb heat air intake in the back top right of the doghouse. 

I don’t know when the oil cooler was relocated by the factory, but the majority of Es and F’s and Cs have the oil cooler mounted in the same location on the lower pilot’s side cowl.

[AJ88V]

Since I started a thread about the doghouse....  One of my ignition wires (pilots side) exits the back of the doghouse and makes a very sharp bend to go around the battery box (1970 M20C).  Never had a problem with it (misfire, failure, radio noise...) in 10+ years, but it just seems wrong.  I don't see a way to reroute it so it has a gentler arc.

Anybody else have this issue?  Any solution?

[Hank]

9 minutes ago, AJ88V said:

Since I started a thread about the doghouse....  One of my ignition wires (pilots side) exits the back of the doghouse and makes a very sharp bend to go around the battery box (1970 M20C).  Never had a problem with it (misfire, failure, radio noise...) in 10+ years, but it just seems wrong.  I don't see a way to reroute it so it has a gentler arc.

Anybody else have this issue?  Any solution?

This is what they look like in my 1970 C:

[AJ88V]

9 minutes ago, Hank said:

This is what they look like in my 1970 C:

Great pic. Thanks.  Guess it's all my ignition wires (was writing from memory)  Yep, that's what mine look like too, maybe a little tighter bend.  Will talk to my mechanic about it at annual next month, but there doesn't seem to be any room to shift the battery box position (again, from memory).

[AJ88V]

Poking around about the whole 'open doghouse' subject, I found this pic in case folks don't know what I'm referring to:

https://mooneyspace.com/uploads/monthly_2018_10/1B96E978-A3C8-4AD1-90C2-72804C9624E8.jpeg.77cfea65df342064965fb8e9e3392f90.jpeg

I was unable to find such a doghouse on an M20C model.  Maybe another subject to take up with my mech next month.  He services mostly antique aircraft and is pretty ready to develop alterations and file paperwork.  Suspect this mod would be 'major' though, since it wasn't installed ever on a C model from the factory.

[Hank]

12 minutes ago, AJ88V said:

Great pic. Thanks.  Guess it's all my ignition wires (was writing from memory)  Yep, that's what mine look like too, maybe a little tighter bend.  Will talk to my mechanic about it at annual next month, but there doesn't seem to be any room to shift the battery box position (again, from memory).

No, the battery box is bolted to the firewall.

Removing requires one person standing outside with a wrench, while a second person slides under the pilot side panel, pulls the carpet back and keeps the bolt from turning while the outside guy removes the nuts. There are four bolts, and some of them go one direction, some the other.

I've had the pleasure of doing this to send the left magneto out for repair; my A&P put it back together and timed it. The right magneto looks very easy to access! Which is the reason the left one died on me . . . .

[47U]

19 minutes ago, Hank said:

No, the battery box is bolted to the firewall.

Removing requires one person standing outside with a wrench, while a second person slides under the pilot side panel, pulls the carpet back and keeps the bolt from turning while the outside guy removes the nuts. There are four bolts, and some of them go one direction, some the other.

I can remove my battery box in less than 10 minutes.  I have the avionics access panels (no 201 windshield mod) in my ‘63C.  I can reach the nuts on the inside sticking my right arm through the avionics access and my left hand on the engine-side of the firewall.  This is possible because my avionics guy does a very clean installation.  Artwork even, if you will.  If your wiring is haphazard, you might not be able to do this.

Or, with a lot of work, the battery could be moved to the aft avionics bay, if your CG supports that change.  

[Hank]

30 minutes ago, 47U said:

I can remove my battery box in less than 10 minutes.  I have the avionics access panels (no 201 windshield mod) in my ‘63C.  I can reach the nuts on the inside sticking my right arm through the avionics access and my left hand on the engine-side of the firewall.    

Duh! It never entered my point head to try this! Lesson learned . . . .

[takair]

Regarding opening the doghouse, I’ve considered this but….the models with open doghouse seem to have a reinforced upper cowl. Perhaps someone with open baffles can take picture of the upper cowl next time it’s off?  I suspect mine would tend to bulge and crack without some reinforcement to accommodate the extra pressure?

[Hank]

I would love to remove my doghouse and replace my 2-year-old baffles with a different set! Because it's almost impossible to find a sheer metal guy willing to repair ugly, cracked, leaky doghouse!

While I've heard about people making the change, they all seem to use the IO engine, which leaves my C out in the cold. Sadly, as a fresh retiree, hiring a DER for a one-off approval will not be happening. I'm saving my pennies for Dynon SkyView install with AP, when the AP is approved.

[Sabremech]

I used Vans RV baffling for the mods I did to the four cowlings. # 1 and # 2 baffles aren’t tall enough for the Mooney cowling and I made those pieces as I didn’t want to rivet on extensions to fill the gap. 
They are great baffles and fit well along with easy to assemble and install. You can add the little bit of sheet metal on this front two cylinders and be in good shape for quite a while. My FSDO liked that I used known parts for my mods. 
David

[hammdo]

What David did with mine:

 

[jetdriven]

Did you notice if it cooled better?

[hammdo]

David did this with his cowling mod before I bought his plane. Here in Texas, 390s or less CHT- depending on my fuel flow - during the summer…

-Don

[Sabremech]

9 hours ago, jetdriven said:

Did you notice if it cooled better?

It did cool better. Several factors I believe that helped in that were closing off the area behind the prop and ring gear with baffling along with the exit air below the cylinders being equal on all four cylinders. The gaps were adjusted to all being the same. That came from reading about airflow and cooling from a Reno air race engineer. 

David

[cliffy]

Moving the battery is not that hard using Mooney parts and its only a log book sign off as a minor alteration. 

[AJ88V]

14 hours ago, cliffy said:

Moving the battery is not that hard using Mooney parts and its only a log book sign off as a minor alteration. 

I have thought  of doing this as well.  Opens up the engine cowl and shifts the CG rearward.  Also gets the battery out of the hot area next to the engine and makes it really easy to install a jumpstart plug.

Moving the CG rearward is a benefit in the short-bodied planes about 97% of the time, but I have flown the plane full seats (kids in rear) and luggage, and moving the battery back might be a real problem for that.

[AJ88V]

On 8/22/2024 at 7:18 PM, hammdo said:

What David did with mine:

 

This is for Sabremech's cowling? (sorry, pretty new here, so not sure what everybody has on their planes)

I see it's on a M20C model.  Would you be willing to share the paperwork that went with this?

The open baffles look tons simpler to maintain and work with.  Even better if it cools better (and my 1970 C doesn't cool as well as I'd like, especially in climb, even modified with adjustable cowl flaps).

Edited August 24 by AJ88V

[47U]

3 hours ago, AJ88V said:

This is for Sabremech's cowling? (sorry, pretty new here, so not sure what everybody has on their planes)

Here’s a link to catch you up… there is a lot of thread drift in areas, but if you have the time to sift through…

 

[Sabremech]

4 hours ago, AJ88V said:

This is for Sabremech's cowling? (sorry, pretty new here, so not sure what everybody has on their planes)

I see it's on a M20C model.  Would you be willing to share the paperwork that went with this?

The open baffles look tons simpler to maintain and work with.  Even better if it cools better (and my 1970 C doesn't cool as well as I'd like, especially in climb, even modified with adjustable cowl flaps).

I can share with you the data you request. 
David

[Shadrach]

On 8/21/2024 at 5:12 PM, AJ88V said:

Poking around about the whole 'open doghouse' subject, I found this pic in case folks don't know what I'm referring to:

https://mooneyspace.com/uploads/monthly_2018_10/1B96E978-A3C8-4AD1-90C2-72804C9624E8.jpeg.77cfea65df342064965fb8e9e3392f90.jpegFetching info...

I was unable to find such a doghouse on an M20C model.  Maybe another subject to take up with my mech next month.  He services mostly antique aircraft and is pretty ready to develop alterations and file paperwork.  Suspect this mod would be 'major' though, since it wasn't installed ever on a C model from the factory.

The airplane in the link does not look modded, it looks like a stock 67 or later E or F. That’s very much what my 67 F looks like with the cowl removed.

[AJ88V]

20 hours ago, Shadrach said:

The airplane in the link does not look modded, it looks like a stock 67 or later E or F. That’s very much what my 67 F looks like with the cowl removed.

Sorry for the confusion, Ross.  I didn't mean to imply the pic I showed was a mod, only that there is a variant for the FI-engined birds and was posting it to show others who may not be familiar

21 hours ago, Sabremech said:

I can share with you the data you request. 
David

Thanks, David.  I'll PM you.  Not to put any pressure on you, but do you think this could be applied to a conventionally-cowled C-model?

22 hours ago, 47U said:

Here’s a link to catch you up… there is a lot of thread drift in areas, but if you have the time to sift through…

 

Thanks for the link, 47U.  Looks like I have a lot of reading to catch up on.