aerobat95 Posted March 17, 2012 Report Share Posted March 17, 2012 Hey guys, as I sit here trying to figure out what I am going to do next to my Mooney I started to think about the clam shell roof vent. If the vent is closed how much drag do you think it produces? I have never used it other than from time to time on the ground to make sure it still works. Has anyone ever removed it? If the plane sits out in the rain is it a source for a leak? As far as what to do next....I am thinking about the tail mods from Lasar.....I have a TDY coming up that will be a month long (going to safety school where I will learn to investigate airplane crashes....basically the military's equivlent of the NTSB) and I won't be flying so I thought what better time to do some mods.... Ray Quote Link to comment Share on other sites More sharing options...
scottfromiowa Posted March 18, 2012 Report Share Posted March 18, 2012 -1-2 knots full open. -None, it's closed... -Nope. If I removed it my wife would die on a hot day... -Not if you have a cabin cover... -Spend it flying/enjoying your plane... Quote Link to comment Share on other sites More sharing options...
DaV8or Posted March 18, 2012 Report Share Posted March 18, 2012 I don't need mine, but I really want it. In the summer on the ground it really helps. When it's closed, there isn't any drag really. If the drain hoses are cracked or clogged, I suppose there could be water getting in. A cabin cover should prevent this problem. I can understand closing it in for good, but not something I want to do. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted March 18, 2012 Report Share Posted March 18, 2012 I just went all through mine. Curiously, the entire front of the plenum was open (right where the windshield frame hoop is). You could put a pack of Marlboro's through it. I sealed it with foam and now it blows like a hurricane with the scoop half open. Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted March 19, 2012 Report Share Posted March 19, 2012 It is useful when it is hot down low, and I wouldn't remove it completely unless you replace it with the later model ventilation system that has the NACA scoop on the dorsal fairing, and all of the internal plumbing to bring the air forward. Norman (testwest) did that on his '77 J for drag reduction, but involved replacing the top fuselage skin, and I believe he said he got the last one. It is probably easy to fabricate a new skin for that region, but perhaps not. The hard part will be getting the new duct work parts to install the new style system. (I'd love to do that some day, but it is a low priority for me. The scoop is draggy when open and noisy.) Quote Link to comment Share on other sites More sharing options...
jezzie Posted March 19, 2012 Report Share Posted March 19, 2012 Ray, There are instructions that is shown on the Mooney Retro fit drawing #940129 if you decide to remove the overhead scoop as I did when I added the dorsal fin scoop. This is on page 2.0 item 4. If you want a copy of it PM me. Eldon Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 13, 2012 Report Share Posted June 13, 2012 How much air flow do you guys get with the overhead vent? Mine has almost no flow to it? Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 13, 2012 Report Share Posted June 13, 2012 Memories from an old M20C... Too much, in the winter at 11,500' Not enough, in the summer at 2,000' Memories from a modern M20R... Plenty of air flow and heat when needed... The old systems were not designed well. Corrosion has often killed their operabillity. They can be rebuilt with some effort. -a- Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 13, 2012 Report Share Posted June 13, 2012 Wonderful... Too damn hot now to rebuild it when I need it and when it's cool in the fall I don't need it anymore... Looks like another long summer of a complaining spouse! Quote Link to comment Share on other sites More sharing options...
omega708 Posted June 13, 2012 Report Share Posted June 13, 2012 Quote: BigTex How much air flow do you guys get with the overhead vent? Mine has almost no flow to it? Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 13, 2012 Report Share Posted June 13, 2012 I pulled the Cabin Overhead Ventiliation System drawings from the parts manual and at the speeds these planes fly, why we don't have more air than we know what do with flowing through those vents. It might be that the valves over the deflectors might not be fully open. Something's not right... At least I hope it's not working as designed and not a design flaw. Quote Link to comment Share on other sites More sharing options...
omega708 Posted June 13, 2012 Report Share Posted June 13, 2012 If you have those drawing electronically, I'd love to have a copy... -JLG Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 13, 2012 Report Share Posted June 13, 2012 Sure... It's a PDF. PM me your email address. Quote Link to comment Share on other sites More sharing options...
omega708 Posted June 13, 2012 Report Share Posted June 13, 2012 Quote: BigTex Sure... It's a PDF. PM me your email address. Quote Link to comment Share on other sites More sharing options...
DaV8or Posted June 13, 2012 Report Share Posted June 13, 2012 Mine works pretty good. I do have the 201 windshield though. I have yet to be in any GA piston plane where the air vents were enough in heat of summer. A/C is the only thing that will really satisfy you when it's really hot. Quote Link to comment Share on other sites More sharing options...
moodychief Posted June 13, 2012 Report Share Posted June 13, 2012 To augment the air coming from the vent above, we have a collapsible camping fan that runs on D batteries. When it is just my wife and I, we set it on top of a headset bag in the back seat and shoot the air forward. At 9,000 feet in the summer I have had to turn off or put on low setting because my wife was getting cold. It is a cheap way of moving air in the cabin. Quote Link to comment Share on other sites More sharing options...
Skybrd Posted June 13, 2012 Report Share Posted June 13, 2012 My former E model Mooney had the roof vent sealed when I bought it. I found it sealed with RTV and the top vent control cable missing to the door opening. I flew this newly purchased Mooney back from Oskhosh to Bakersfield and at times almost fried. When I arrived at my home airport, unsealed the vent and jury rigged a hold on the door to open or close it. I ended up buying used parts to repair the missing cable and now it's back to the correct operational condition. I found out the vent system has a drain system using a drain hose if water or rain enters it. My two cents on this issue: is to keep your roof vent operational since on hot days it will be needed. Quote Link to comment Share on other sites More sharing options...
M20F Posted June 13, 2012 Report Share Posted June 13, 2012 Have a 67 M20F with stock windshield and I get in my opinion really good air flow from the roof vent. This is one of the cooler airplanes I have flown in. The under the panel vents though leave a lot to be desired (the only cooling I get is from the roof top vent). Quote Link to comment Share on other sites More sharing options...
Gone Posted June 13, 2012 Report Share Posted June 13, 2012 I like my roof vent as well. Clarence had to do some surgery on it a two years ago when the thing siezed up, but it works fine now. I have had to replace the knob and I now carry the small allan key that fits into the machine screw for it. Clarence's own modified E model has a NACA vent in the dorsal extension that replaces his roof vent and he says he likes that better. I have never experienced it, but I think it is quite a job to replace the dorsal with the fiberglass one just so you can hide the ELT antenna and put a NACA vent in. Quote Link to comment Share on other sites More sharing options...
M20F-1968 Posted June 13, 2012 Report Share Posted June 13, 2012 I removed mine from my 1968 F model, but I had an Ovation available to pull parts from. Namely the entire new ventilation system. It wouyld be difficult to find these parts without the factory as a source. I changed the top skin and it is a die formed part so it too would be a difficult skin to make unless you have a very good sheet metal mechanic. The top skin is also a thin skin and difficult to work with which is another reason you would need an experienced sheet metal mechanic. The other obstacle is the authority to do the work. I do so with DER approval. John Breda Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 13, 2012 Report Share Posted June 13, 2012 My roof vent opens just fine but just no flow. It sounds like I just need to dig into it and see what's going on. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted June 13, 2012 Report Share Posted June 13, 2012 The J plenum is open in the front. Blocking it off with FAA-approved mattress foam robbed from the street curb really helped to up the air volume. That dang thing sure is noisy though. Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 13, 2012 Report Share Posted June 13, 2012 There is a vent on the pilot side that is duplicated on the copilot side on newer models. Wemac??? The naca duct in the tail seems to work well. But dual wemacs work the best. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Lood Posted June 14, 2012 Report Share Posted June 14, 2012 The vent on my F works very well. In fact, I don't think I have ever opened it more than 1/4. As soon as I turn the knob, the airflow is there immediately and to my opinion, the worst part in the system are the round, plastic disks on the inside. Apparently, these are supposed to direct airflow in different directions when turned, but just looking at the way they are formed, it seems that they might actually restrict the airflow instead. Mine are really flimsy and I just dont like them. I wouldn't close the vent. It helps a lot in summer - even on the ground. Quote Link to comment Share on other sites More sharing options...
flight2000 Posted June 14, 2012 Report Share Posted June 14, 2012 I share the same experience as Lood. Mine works really well, but my plastic vents actually work as well for directing air. Mine also has two "eye ball" vents in the front (one on each side) that allows air into the cabin so between the two, we get enough air moving that stays fairly cool. Get high enough and I've had to close the vents because it got to cold... If yours isn't working that well, it might be clogged or a duct has a hole in it allowing the air to escape before reaching the cabin vents. Brian Quote Link to comment Share on other sites More sharing options...
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