Speedbrakes failed after only 31 years of use

[larryb]

On 4/11/2018 at 9:45 AM, gacoon said:

That was a very good guess - I did email Precise Flight and cables are $100 and conduits are $80, that is per side.  I'm still inclined to remove them as I would get a very good weight payoff.  This is right out of the POH:

Speedbrakes 12.5 lbs, Standby Vac 12.04 lbs, Vacuum System 8.3 lbs.  Looking at gaining 32lbs useful load.  Digital AI is lighter also, but you really do not save any weight as the standby battery brings it back to about the same as the original AI.

Note: when I emailed Precise Flight they were nice enough to send me the old Mooney Vacuum speedbrake install manual, nice to know we can still get access to that.

 

 

 

I really appreciate my speed brakes, no way would I remove them.  They were certainly a desire when I upgraded from my J which does not have them to my K which does.

When flying an instrument approach at my home airport ATC often needs us GA types to keep our speed up to play nicely with the jets. Without speed brakes I could not do this and get down to gear speed without leveling out and going above the glideslope. Then there is the slam dunk approach or descending into an airport in a mountain valley. For my trips these are all pretty common.

If you went to the electric AI you could remove the standby vac system and save  your 12 lb.

[kortopates]

 
I really appreciate my speed brakes, no way would I remove them.  They were certainly a desire when I upgraded from my J which does not have them to my K which does.
When flying an instrument approach at my home airport ATC often needs us GA types to keep our speed up to play nicely with the jets. Without speed brakes I could not do this and get down to gear speed without leveling out and going above the glideslope. Then there is the slam dunk approach or descending into an airport in a mountain valley. For my trips these are all pretty common.
If you went to the electric AI you could remove the standby vac system and save  your 12 lb.

I couldn’t agree more Larry. Despite how little I use mine, I still appreciate them whenever I do occasionally use them. Rarely do I need them coming down from up high in the FL’s; it’s always been descending for an approach. They occasionally get used for other things too light encountering severe turbulence to help slow down to get the gear down soonest.
For the couple hundred $ it took to refurbish them after over 30 years it’s one of cheapest to maintain accessory’s on my Mooney.
And Iam OCD on saving weight too, my K has over 1100 lbs useful load because of it despite speed brakes and 115 cuft O2 cylinder!


Sent from my iPhone using Tapatalk

[kortopates]

BTW, doesn’t Jimmy assign a $4000 value to speed brakes? Thus it would be the same subtraction from the previous value.

 

 

Sent from my iPhone using Tapatalk

 

[carusoam]

Great Post, Mike!

Thanks for sharing the details!

Best regards,

-a-

[Bob_Belville]

@Precisemike, @kortopates

Like Paul I use my SBs only rarely but really appreciate that a previous owner added the mechanical version to my M20E in 1997. 

• Zero maintenance in 22 years,
• Jimmy values SB @ $2000,
• With the mechanical SBs I've learned to keep my hand on the control lever while using the SBs to lose a few thousand feet in a hurry. When I get through the cloud layer or get close to the pattern altitude after crossing higher terrain near my home drome I remember to retract the SB and continue normal approach.

Thanks for a great product Mike!

[shawnd]

I am now in need of the bellows assembly as well for my speedbrakes in 252, p/n: 20412-4-0. The fabric portion is torn causing a leak. Anyone have a spare or have good ideas on how to repair, will be appreciated. @M20Doc?

[jetdriven]

They don't support spares for The mechanical speed brakes.  And the electric SB kit is $7800 and a lot of labor to install them too.  

[shawnd]

Yeah very likely no new ones but was wondering if there’s working spares from parts pile. Or innovative ways to fix it. 

[ArtVandelay]

They don't support spares for The mechanical speed brakes.  And the electric SB kit is $7800 and a lot of labor to install them too.  

I have the older electric ones (series 100?), do they support them?

And there’s some cam adjustment docs but they apply to the 2000 series.

[Will.iam]

On 12/14/2019 at 3:59 PM, kortopates said:

I couldn’t agree more Larry. Despite how little I use mine, I still appreciate them whenever I do occasionally use them. Rarely do I need them coming down from up high in the FL’s; it’s always been descending for an approach. They occasionally get used for other things too light encountering severe turbulence to help slow down to get the gear down soonest.
For the couple hundred $ it took to refurbish them after over 30 years it’s one of cheapest to maintain accessory’s on my Mooney.
And Iam OCD on saving weight too, my K has over 1100 lbs useful load because of it despite speed brakes and 115 cuft O2 cylinder!


Sent from my iPhone using Tapatalk

Wow 1100 lbs where else did you manage to lighten the load? What were the more heavy items?

[PT20J]

25 minutes ago, ArtVandelay said:

 

 

I have the older electric ones (series 100?), do they support them?

And there’s some cam adjustment docs but they apply to the 2000 series.

 

 

I had a 100 series unit overhauled by Precise Flight in June 2021 - $1200. I had to ask them to send the documentation that's not currently on the website.

Service & Maint manual.pdf

100 Series ICS.pdf

100 SERIES SCHEMATIC WIRING.pdf

 

 

[hais]

On 8/4/2016 at 4:38 AM, BobAustin said:

Problem solved

Located a rep[acement "vacuum pot" and David at DuGosh installed it. 

Works great.  Took 4 hours to remove and replace.

Wouldn't it be great to have a searchable knowledge bank on here you could file this solution under?

[hais]

Moderators : thoughts on hosting and linking one of these?

 

https://helpjuice.com/blog/open-source-knowledge-base#docuwiki

[shawnd]

I fired up this old thread to hopefully get an answer for a fix or spare for the vacuum bellows assembly  people started responding to years old responses, though does have valuable data. 

[jetdriven]

1 hour ago, ArtVandelay said:

 

 

I have the older electric ones (series 100?), do they support them?

And there’s some cam adjustment docs but they apply to the 2000 series.

Probably. But they arent selling any parts for the kind that are actuated by the rubber bellows. Someone could do well engineering a repair to that bellows.

[Guest]

3 hours ago, shawnd said:

I am now in need of the bellows assembly as well for my speedbrakes in 252, p/n: 20412-4-0. The fabric portion is torn causing a leak. Anyone have a spare or have good ideas on how to repair, will be appreciated. @M20Doc?

Sadly there are no repair schemes available, I’m not sure what to suggest.

[jetdriven]

if you send the rubber bellows maybe we can take a look. Its rubber

 

[DonMuncy]

I had a Lotus Elan with "pop up" headlights that used a rubber bellows that sounds similar to what is being discussed. When one of mine leaked, I used a hot patch like we used to use on inner tubes. It worked for years.

[Guest]

1 hour ago, shawnd said:

I fired up this old thread to hopefully get an answer for a fix or spare for the vacuum bellows assembly  people started responding to years old responses, though does have valuable data. 

PM sent to you.

[PT20J]

2 hours ago, DonMuncy said:

I had a Lotus Elan with "pop up" headlights that used a rubber bellows that sounds similar to what is being discussed. When one of mine leaked, I used a hot patch like we used to use on inner tubes. It worked for years.

Bet you didn’t look as good in it as Diana Rigg did in the Avengers. 

[DonMuncy]

Just now, PT20J said:

Bet you didn’t look as good in it as Diana Rigg did in the Avengers. 

Not by a long shot. I really enjoyed that series. I also really liked the car. Better than any other vehicle I have ever owned. Too bad it was typical british with oil leaks everywhere, Lucas electrics, etc. If I was younger and had made the time, I would have liked to fix it and still be driving it. I have had a couple of Miatas, and they are close, but much heavier than the Elan.

[PT20J]

10 minutes ago, DonMuncy said:

Not by a long shot. I really enjoyed that series. I also really liked the car. Better than any other vehicle I have ever owned. Too bad it was typical british with oil leaks everywhere, Lucas electrics, etc. If I was younger and had made the time, I would have liked to fix it and still be driving it. I have had a couple of Miatas, and they are close, but much heavier than the Elan.

I hear you. I always wanted a Jag XKE. Then I joined a work car pool and when it was only two of us and Ed’s turn to drive he would bring out his XKE. I was never certain of getting to work.

[0TreeLemur]

Gear down at the FAF.  Those are about all the speed brakes needed on a J, no?  I mean really, is shock cooling a serious problem with an IO-360?  Some writers write that it's a myth.   Just curious.  Other than convenience for occasional use to let a controller slam-dunk you, do speed brakes do something you can't do otherwise in a J?   

 

[larryb]

Yes. They allow you to fly an approach at 150 kt and slow to gear speed and also stay on the GS. That may not matter everywhere but it does matter when you have to sequence with the jets at a big airport.

[0TreeLemur]

Aaah.   I don't do that very often.