Manual step conversion

[takair]

Electric conversion update:  I have everything I need and  built up outside the plane.  New actuator is better than I hoped.  Looks like the “kit” comes in right around 0.5lb. Hoping this will be offset by removal of the crank and long cables.  Won’t do that until I’m comfortable it all works.  Just need a reasonably mild day or will need to crank some heat in the hangar.  Worst case, I will try it all out the week after Christmas.  The actuator is half travel and will use a pulley and cable to double the travel, pulling the step up.  Going down I needed some return mechanism.  I guess the vacuum steps have a spring return.  I’m going with a bungee for the crank conversion to keep the weight and complexity down.  It just needs to get the step moving down.  Will require minimal wiring if your battery is in back or you have some source of 12v back there.  Step will come up with either the beacon turned on or master on and come down when power off.  

[Skates97]

I may be wrong but I thought my vacuum step on my 65D just came back down from the weight of the step when the vacuum pressure dropped. I have played around with it a little because it sometimes sticks and pushing up and letting it come back down I did not feel anything other than the weight of it. 

[takair]

1 hour ago, Skates97 said:

I may be wrong but I thought my vacuum step on my 65D just came back down from the weight of the step when the vacuum pressure dropped. I have played around with it a little because it sometimes sticks and pushing up and letting it come back down I did not feel anything other than the weight of it. 

I wonder if it is serial number specific?  I have seen diagrams with and apparently without the spring.  In looking at the geometry, gravity alone would likely have a hard time pulling it down consistently unless very well maintained.  

[HRM]

6 hours ago, takair said:

I guess the vacuum steps have a spring return.

Mine has a very complicated spiral spring that I once foolishly played with. I will never do that again.

[Skates97]

4 hours ago, takair said:

I wonder if it is serial number specific?  I have seen diagrams with and apparently without the spring.  In looking at the geometry, gravity alone would likely have a hard time pulling it down consistently unless very well maintained.  

I will have to take a closer look during annual this coming week.

[takair]

12 minutes ago, Skates97 said:

I will have to take a closer look during annual this coming week.

Can you take some pictures?  I’m curious what this spring looks like, if yours has it.

[Skates97]

13 minutes ago, takair said:

Can you take some pictures?  I’m curious what this spring looks like, if yours has it.

Will do, expect to have some for you by mid week as I'm taking panels off in preparation for my IA to come.

[carusoam]

Bi-metallic(?) Looking flat spring...  winds up when the step is up.  Gets unwound when the step is down...

When the new owner raises the step by hand, from the outside... this spring comes unsprung and twists up to release the energy... getting it wound back up properly is a small challenge.  

dirty tracks inhibit motion.  A little dirt, and the step doesn't come down...  a little cleaning and pushing the step up, the young pilot learns  a lot about flat spring winding...  

I came across another flat spring use the other day... a pull start device on small engines rewinds using a flat spring... abusing the start system has a familiar failure to it. Hence learning about flat springs again... 

Expect the force of the wound up spring to be about the same force of the weight of the step and associated leg...

Be careful with springs.  They have a tendency to release energy quickly and can be made of sharp edges... safety glasses and gloves alert...

PP thoughts and fuzzy memories... not a mechanic.

Best regards,

-a-

[RLCarter]

"Clock Spring" They can be tricky to re-wind, too much tension and the bind up and break too loose and they won't retract. I've done hundreds of them on pull starters mainly