What is the legality of removing my step and patching the resulting hole?

[takair]

5 hours ago, Ragsf15e said:

You’re making a good sales pitch for the electric step!  Mine is a ‘68, so fixed.  Making it retractable would entail making a bigger opening in the side of the airplane for it to pull up?  Does water get sprayed up there during ground ops?

I’ve looked at retrofitting a few Mooneys that don’t have retractable steps.  The simplest way would be to acquire parts from a salvage plane or from someone removing one to save weight :-).  However, it will require some sheet metal work on the bulkhead, in the form of an additional doubler....so it rapidly gets somewhat expensive.  I’ve also considered a new retractable step assembly that adapts to the existing fixed step structural attach points.  It can be done, but I’m not sure it would be a popular retrofit....questionable ROI.  I was hoping it would work for long bodies as well..but their step is not attached to the bulkhead at all.  The step on a long body is mounted somewhere near the middle of the baggage area and would either eat into the baggage area or require some intricate kinematics.   
 

As for water, I’ve seen no hint of moisture getting in there and have some sensitive avionics inches above it.  With the step retracted, the fairing closes it up fairly well.  When it is down, the biggest hazard might be wildlife, but I’ve never had them get in that way as far as I can tell.  Seems they prefer getting in through torn rat boots on the gear.

[Nokomis449]

13 hours ago, Ragsf15e said:

Mine is a ‘68, so fixed. 

 

12 hours ago, bluehighwayflyer said:

The last retractable steps were in ‘67.  

My '68 G, #680092, has a vacuum step.

[Raymond J1]

In order not to have to ask myself all these questions, I decided to redo everything according to the original. However, I admit that a vacuum leak on the step servo puts in difficult the directional, the artificial horizon and the positiv control. And this eventuality bothers me. I did some testing, the equivalent of 15 " of manifold pressure are sufficient for retraction with the original chrome slide. So right now I'm looking to connect this particular servo to the intake manifold directly. This would allow me to keep the initial principle of operation : automatic rise at Engine Start, descent of the retract step at reduction.

 

[Pasturepilot]

19 hours ago, Ragsf15e said:

 Does water get sprayed up there during ground ops?

I’m based on grass. The clippings from the runway do pile up yearly back there and require a good clean-out at annual, so I’d have to say water would also be entering as well for rainy day ops. 

[takair]

6 hours ago, Raymond J said:

In order not to have to ask myself all these questions, I decided to redo everything according to the original. However, I admit that a vacuum leak on the step servo puts in difficult the directional, the artificial horizon and the positiv control. And this eventuality bothers me. I did some testing, the equivalent of 15 " of manifold pressure are sufficient for retraction with the original chrome slide. So right now I'm looking to connect this particular servo to the intake manifold directly. This would allow me to keep the initial principle of operation : automatic rise at Engine Start, descent of the retract step at reduction.

 

Raymond,

While this is a good idea to make the step function, the failure mode can be quite expensive, in the form of a lean running cylinder, should you have a leak in the servo.  While a vacuum leak right now affects vacuum equipment performance, when connected to your engine it could effect power, efficiency, and reliability of the engine.  I suppose close monitoring can mitigate this, but it is something to consider.

[N201MKTurbo]

That won’t work!

When you increase manifold pressure, you lose manifold vacuum. At full throttle, there is no manifold vacuum and your step will drop.

Cars can use vacuum for brakes and actuators because they rarely run at high power settings and most have vacuum tanks to store vacuum just in case.    

[Nokomis449]

Vacuum steps use vacuum from the vacuum pump, not the engine. what he's saying is he has to run the engine up to get the vacuum pump spinning fast enough to pull the step up. I would be afraid that a larger tear in the step bellows would lead to failure of the vacuum instruments in the panel.

[takair]

9 minutes ago, Nokomis449 said:

Vacuum steps use vacuum from the vacuum pump, not the engine. what he's saying is he has to run the engine up to get the vacuum pump spinning fast enough to pull the step up. I would be afraid that a larger tear in the step bellows would lead to failure of the vacuum instruments in the panel.

I read it as he wants to go straight to the engine; “So right now I'm looking to connect this particular servo to the intake manifold directly.”

[Ragsf15e]

9 hours ago, Nokomis449 said:

 

My '68 G, #680092, has a vacuum step.

Interesting.  Im 68-0164.  I guess they ran out of retractable steps somewhere between there and just started bolting on the steel tubes!

[Nokomis449]

Ah, when he said he decided to "...redo everything according to original...", I assumed he meant keeping it plumbed to the vacuum pump but he had to increase engine power for it to create enough vacuum.  I guess I'm having issues with reading uncomprehension.

[aviatoreb]

There are two things on my airplane, hanging in the wind that sometimes I look at and think about chopping off.  Not the wings.

easiest would be the step, but the step is nice to - step on. I am told the more modern aero steps don't make much difference if removed,  Like less than half a knot, so hard to measure a difference, so why bother.

The other thing I look at is my towel bar vor.  One of these days I may wire that to antenna hidden in the wings.  Seems like that really should make a small but measurable difference.

[Nokomis449]

@Ragsf15e, do you have the Johnson bar or electric gear? I'm wondering if there is a correlation between electric gear having fixed step, and manual gear having vacuum that year. I know electric gear was an option that year, maybe the fixed step was, too. 

[orionflt]

8 hours ago, Raymond J said:

In order not to have to ask myself all these questions, I decided to redo everything according to the original. However, I admit that a vacuum leak on the step servo puts in difficult the directional, the artificial horizon and the positiv control. And this eventuality bothers me. I did some testing, the equivalent of 15 " of manifold pressure are sufficient for retraction with the original chrome slide. So right now I'm looking to connect this particular servo to the intake manifold directly. This would allow me to keep the initial principle of operation : automatic rise at Engine Start, descent of the retract step at reduction.

 

Going directly to the engine is not a good idea, if you have a failure of the servo or the lines to it you will create a major manifold leak in your engine. That is going to affect power and performance.  
the FAA will not approve that modification because of that. 
BTW, that type of mod would require FAA approval. 
 

Brian 

[Ragsf15e]

2 hours ago, Nokomis449 said:

@Ragsf15e, do you have the Johnson bar or electric gear? I'm wondering if there is a correlation between electric gear having fixed step, and manual gear having vacuum that year. I know electric gear was an option that year, maybe the fixed step was, too. 

Well according to the logs, she was born with a johnson bar, but then modified with electric gear at the factory before being delivered.  Weird.

I definitely do not have all the flush rivets that the earlier models have.

Edited February 21, 2021 by Ragsf15e

[Nokomis449]

Where exactly are these flush rivets you speak of?  I'm at the hangar for a few more minutes and will check...

[Nokomis449]

Just now, bluehighwayflyer said:

In front of the spar on the bottom of the wing, from memory.  Also, are the screws holding your windows and windshield in place flush or pan head?  

Gotcha.  Rivets are flush under the wing.  My side window screws are pan head, and the windscreen screws are flush.

[Ragsf15e]

If you look at a ‘67, I think all the rivets on the top of the wing all the way back are flush.  My ‘68 only has flush on the first 1/3 as you move aft.

[McMooney]

Somehow my fixed step fell off the pkane today 8)

[orionflt]

That tends to happen when you tighten the bolts the wrong way. 

[McMooney]

Somehow my fixed step fell off the pkane today 8)

[carusoam]

Mooney... always flush rivets past the first critical third...

Like tiny speed brakes... they are extra affective in this area...

 

rotating Jim’s pic...

-a-

[Ragsf15e]

Interesting, I’m sure there’s something different about flush rivets that changed at ‘68... ill take similar pictures of my wing next time out.

[jetdriven]

5 hours ago, bluehighwayflyer said:

I’d be interested in hearing if any M20s have flush rivets over the entire top of the wing?   I don’t think they do, though.  Both my current ‘65 C and my previous ‘78 J are the same in this regard.  I think this is as good as it has ever gotten on the top of the wing.  Does anyone have more flush riveting up top than this?

Man the tin work on the 67-68-69 birds was really something.  Skilled craftsmen. 

[carusoam]

Speaking of the legality part...

The first line of defense...

Is it on the MEL, minimum equipment list?

Each POH has an MEL for the plane... for VFR, Day/night and IFR, Day/night...

 

How would we know if flying with a missing aileron would be OK, or not?

Essentially, how would I definitively know if the step wasn’t an essential part of the airframe..?

Would I simply ask my favorite mechanic?

Interesting PP question... 

Best regards,

-a-

[MB65E]

1 hour ago, carusoam said:

Speaking of the legality part...

The first line of defense...

Is it on the MEL, minimum equipment list?

Each POH has an MEL for the plane... for VFR, Day/night and IFR, Day/night...

 

How would we know if flying with a missing aileron would be OK, or not?

Essentially, how would I definitively know if the step wasn’t an essential part of the airframe..?

Would I simply ask my favorite mechanic?

Interesting PP question... 

Best regards,

-a-

I would back track that aileron question to the 337 requirement. Would a missing aileron appreciably change or alter the flight characteristics? Yes. Thus required for flight. 
-Matt