M20F Vacuum system & Step simplification

[podair]

Hi I am currently redoing my panel and am looking at the various hoses sticking out of my vacuum regulator in my 1967 M20F, after the two main outputs on the reg. It appears there are a number of them on Tees that are surplus to requirement, considering the M20F came initially with a Brittain a/p and DI which I assume were vacuum driven but are no longer installed. The only two things I believe need Vac are the AI (Sigmatek 5000b) and the retractable step. I have a large black 3/8in hose connected to the vac warning lights. The step is connected to the AI with a 1/8in clear hose. The main 3/8in hose is connected to the AI, and another one is just blocked off. There is another 3/8in hose coming out of the AI as well, going to the air filter in the footwell. They are huge hoses which seem crammed in the place with tight bends so if I can simplify things , the better. 

As these large black hoses take a lot of space in a cramped area, can I simplify the system as following:

-1) connect the 3/8in to the AI as before, and the one going to the filter

-2) connect the AI gauge output to a 1in UMA suction gauge and remove the two low and high lights 

3) connect the step to the other 3/8in output with an adapter to 1/8 ? I don't like the fact that the step gets its vacuum from the AI , I'd rather it goes to the regulator/filter. Is this normal? From the manuals it seems it was connected to the DI so I guess it is. 

Alternatively, leave it connected as before , have the retractable step connected to the AI and the vac gauge to a 3/8in fitting instead of where the switch was. Or keep the switch and the two lights but it is all quite bulky. I quite like the idea of a light instead of a gauge for the suction but a gauge is useful as well and less bulky than the two lights and associated wiring.

 

In short, instead of the bulky T below can I just run a new 3/8 hose to the AI and remove that metal clamp on the other one?

 

edited to add... are these black hoses 3/8 as I refer to them above or 5/8 ? I think 5/8 coming from the pump , and 3/8 going to the instruments, correct?

 

Edited February 20, 2018 by podair

[BDPetersen]

When I removed my vacuum AI to install a G5, I discover that instrument had an extra tap that serviced the step retract. I was puzzled as to what it was for awhile. 

[podair]

OK so not only on mine then. I guess looking at the original parts manual it has always been that way. I hope there is a filter somewhere down that line as I don't like the idea of the AI being the vacuum source for the retract system when sometimes the boot falls off and perhaps debris can get into the system. However thinking about it maybe the small vacuum motor is protected, but when the boot falls off the step doesn't retract, so it must be exposed somewhat. I would prefer to hook it up to the regulator directly but maybe there is a reason to stick to the original setup.

 

 

[Shadrach]

I'll take a look at the MM as well as the my panel pics from my 67F.   I still have the Brittain system and all of the instrument hoses are small, black soft hoses with .25" ID if I  recall correctly.  There is nothing inherently wrong with the the vacuum supply for the step coming from the AI.  As someone who has worked behind the panel of an F, I would simply urge you to be thoughtful about converting a coupled string of hoses to a single.  The coupler may be there to facilitate maintenance.   I would certainly remove that unused T fitting but I would also consider the access ramifications of going with a single continuous hose. It is nice to be able to easily break a line rather than contorting your hands and arms through the backside of a panel through hoses, wires and zip ties that weren't properly flush cut (all of the zip ties in your photo look like cat scratchers).

Slightly off topic, invest in one of these for zip tie work:

https://www.globalindustrial.com/p/tools/Pliers-Vise/Pliers11/midget-lightweight-diagonal-cutters-d275-5?infoParam.campaignId=T9F&gclid=EAIaIQobChMIieqv-c602QIVVwOGCh3a0wC9EAQYBCABEgIGL_D_BwE

or better yet something like this...

https://www.grainger.com/product/1A887?cm_mmc=PPC:+Google+PLA&s_kwcid=AL!2966!3!50916772077!!!g!71846424079!&ef_id=Wm9gGQAAAHp5bDCT:20180220142753:s&kwid=productads-adid^50916772077-device^c-plaid^71846424079-sku^1A887-adType^PLA

 

 

Edited February 20, 2018 by Shadrach

[takair]

4 hours ago, podair said:

OK so not only on mine then. I guess looking at the original parts manual it has always been that way. I hope there is a filter somewhere down that line as I don't like the idea of the AI being the vacuum source for the retract system when sometimes the boot falls off and perhaps debris can get into the system. However thinking about it maybe the small vacuum motor is protected, but when the boot falls off the step doesn't retract, so it must be exposed somewhat. I would prefer to hook it up to the regulator directly but maybe there is a reason to stick to the original setup.

 

 

An alternative is to convert the step to electric.  In converting our manual crank to electric, we saved 1 lb.  I'm pretty sure the vacuum step conversion will be similar, if removing all of the hoses and accessories.  Our design work is done and working with the FAA on PMA.  Not sure how that works with UK or French registered aircraft.  Where is your aircraft registered?  I know they are sometimes reluctant with an STC, but this will be a minor alteration.  PM me if you are interested in more details.

[cliffy]

I'm going electric step from manual  :-)

[podair]

thanks for the advice Shadrach. Cat scratches indeed, looking at my hands after removing the instruments! What a pain it is to work in that space. That's partly the reason I want to simplify things, everything is packed so tightly and difficult to access. Mind you that photo is a lot nicer than now with all the cable ties removed, a huge mess. I will definitely get one of these cable tie clamps (I have the cutter already). 

After second thougths I think I will keep the step as is to the AI (maybe look at electric step). I think I will fit new vac hoses to the AI as the new position of the AI puts a lot of stress and bending on the old hoses and I can't see the point of keeping the blocked off Ts and their associated clamps. Not sure yet whether to keep the vac switch and lights or fit a gauge instead, any opinions anyone? G5 is for next Xmas anyway but I will keep the AI as backup.

So I will have two hoses coming out of the regulator, one to the AI (and a further one from the AI to the filter in the footwell as well as the smaller one out to the step) , and another to the vac switch or gauge. 

 

Edited February 20, 2018 by podair

[Shadrach]

2 hours ago, podair said:

thanks for the advice Shadrach. Cat scratches indeed, looking at my hands after removing the instruments! What a pain it is to work in that space. That's partly the reason I want to simplify things, everything is packed so tightly and difficult to access. Mind you that photo is a lot nicer than now with all the cable ties removed, a huge mess. I will definitely get one of these cable tie clamps (I have the cutter already). 

After second thougths I think I will keep the step as is to the AI (maybe look at electric step). I think I will fit new vac hoses to the AI as the new position of the AI puts a lot of stress and bending on the old hoses and I can't see the point of keeping the blocked off Ts and their associated clamps. Not sure yet whether to keep the vac switch and lights or fit a gauge instead, any opinions anyone? G5 is for next Xmas anyway but I will keep the AI as backup.

So I will have two hoses coming out of the regulator, one to the AI (and a further one from the AI to the filter in the footwell as well as the smaller one out to the step) , and another to the vac switch or gauge. 

 

As an aside, Our Mooney (67F) has been in the family since early 1968. It was a factory demonstrator at a local dealership when my Dad bought it.  I say this because I can say without qualification that our vac operated step has been functioning beautifully for half a century and is still going strong.  Its a bit less enthusiastic when the temps drop below -6C, but then who isn't??? It has always worked as it should and I've no reason to improve on it. 

I think Takair has come up with an interesting solution in the electric conversion. If I had a failure and were unable to get parts, or wanted to go all glass and get rid of the vac system, I would go that route. 

 

Edited February 20, 2018 by Shadrach

[podair]

Great to hear the Mooney has been in the family that long, fantastic! I have had mine for 10 years now and only missing the first couple years in logs. It was imported new to Denmark from the factory (I have the invoice) in 1967 sn 60327 (what's yours?) and has been on the same registration and orange paint since then.   

The vac step looks reliable enough to keep going, just slightly annoying at times when the rubber boot falls off. Easy to spot as I lose 3-4kt in cruise!

[kpaul]

28 minutes ago, Shadrach said:

functioning beautifully for half a decade and is still going strong. 

5 years does not seem that long.  How about half a Century? 

[Shadrach]

1 hour ago, kpaul said:

5 years does not seem that long.  How about half a Century? 

 Edited!  I’m too young to be losing it. I blame it on having a two-year-old and an infant in the house!

Edited February 20, 2018 by Shadrach

[Shadrach]

2 hours ago, podair said:

Great to hear the Mooney has been in the family that long, fantastic! I have had mine for 10 years now and only missing the first couple years in logs. It was imported new to Denmark from the factory (I have the invoice) in 1967 sn 60327 (what's yours?) and has been on the same registration and orange paint since then.   

The vac step looks reliable enough to keep going, just slightly annoying at times when the rubber boot falls off. Easy to spot as I lose 3-4kt in cruise!

670422. Given Mooney’s production volume in 1967 they are probably a few months a part.

Ours is a time capsule but still shows well from a distance.  All original paint.  I just found this random photo online of me and my wife taxiing at Peachtree Dekalb in Atlanta. I’m trying to imagine why a stranger would take a picture of an old Mooney and  post it on line.

Edited February 20, 2018 by Shadrach

[podair]

transatlantic cousins I guess... original paint too, looks ok when I get around to clean it , apart from abrasion on the leading edges. 

I once waited for a taxi early evening at a small airfield in the UK and in the space of a quarter of an hour at least half a dozens guys had stopped by on their way back home from work, looked at the apron, taken a notepad out, and snapped a few photos. A few days later the photo was on a website. Whatever floats their boat I guess, much better photographers than I am, so at least I have a decent selection of snaps of my plane on the web. Here is one, as well as one taken at Gatwick airport in 1969 (look at the cars in the parking lot!) !

damn step is sticking out on that one!

 

Edited February 21, 2018 by podair

[podair]

back to the original question...

Any objections by anyone if I connect the step to the second port on the vac regulator and connect a gauge to the gauge output on the AI?

Just makes more sense to me and helps with the tubing. 

 

[Shadrach]

28 minutes ago, podair said:

back to the original question...

Any objections by anyone if I connect the step to the second port on the vac regulator and connect a gauge to the gauge output on the AI?

Just makes more sense to me and helps with the tubing. 

 

If the port is available, I don't see why not. It's really up to whomever is signing the logs.  Also, I would keep the Hi/Lo Vac annunciators and add a gauge. Our bird came from the factory with both.   When the pump fails, the annunciator will tell you before the gyros wind down and tumble (I speak from experience). 

[Shadrach]

37 minutes ago, podair said:

transatlantic cousins I guess... original paint too, looks ok when I get around to clean it , apart from abrasion on the leading edges. 

I once waited for a taxi early evening at a small airfield in the UK and in the space of a quarter of an hour at least half a dozens guys had stopped by on their way back home from work, looked at the apron, taken a notepad out, and snapped a few photos. A few days later the photo was on a website. Whatever floats their boat I guess, much better photographers than I am, so at least I have a decent selection of snaps of my plane on the web. Here is one, as well as one taken at Gatwick airport in 1969 (look at the cars in the parking lot!) !

damn step is sticking out on that one!

 

Great photos!  What's the performance like with a 3 blade?

[Guest]

14 hours ago, Shadrach said:

670422. Given Mooney’s production volume in 1967 they are probably a few months a part.

Ours is a time capsule but still shows well from a distance.  All original paint.  I just found this random photo online of me and my wife taxiing at Peachtree Dekalb in Atlanta. I’m trying to imagine why a stranger would take a picture of an old Mooney and  post it on line.

I’ve run in to numerous guys from England while sitting beside my plane at Oshkosh, they cruise the rows taking pictures of planes making notes etc.

Clarence

[Igor_U]

67F here; S/n 670091. A bit older then yours (first flight was October 1966) as '67 models were produced in fast pace.

I have no original paint pictures but I believe it was orange and white.

Below as picture taken after a new paint job over 10 years ago.