Hangar door???

[GeoHorn]

This Topic/Thread was very kindly split-off from one discussing Kubota Prices because it inadvertently hijacked the original. Thx NIW.

January 2022 we purchased a L2501 HST with quick attach that included a new unused set of 42 inch forks.
Just under 70 hours and was like new. Bucket looked like it had been lightly used and PTO had never been used. Paid $18,500 no tax.
I don't think we could find one for that price now - only 14 months later.

You were lucky to fine THAT one even at That Time. It was a one-off.

In May, 2018 I bought my 390-hour M4700DT with FEL & bucket for $17K. I doubt that could be repeated either. Here’s the moment of unloading:

 

[Orangeglow]

GeoHorn, that is a very nice tractor, and looks to be in awesome shape. Very interesting door arrangement.
Is that something you came up with on your own, or a manufactured one ?

 

[GeoHorn]

GeoHorn, that is a very nice tractor, and looks to be in awesome shape. Very interesting door arrangement.
Is that something you came up with on your own, or a manufactured one ?

I did that door on my own. I went without a door for two years and spent the time with a lawn chair and beer visualizing it before coming up with the final design.
My intent was to avoid the problems of bi-fold doors (loss of overhead/height) and of hydro-swing doors (hazard of wind when open…. which both types suffer.) I also did not like the idea of side-rolling doors (didn‘t want the physical effort to open/close them…nor have them subject to the danger of collapse due to wind. Saw that at the airport one day when a storm “inflated” a hangar and dropped the door onto ‘planes and trucks stored inside for protection from that very storm.)

I wanted the door to withstand wind regardless of position. I also didn’t like the cost plus shipping plus installation of the other types.
I ended up with this idea…using a common boat-lift …and SS cable rated at 7K working load… in triplicate…which provided a good safety-margin …(door weighs 2400 by calculation of materials)…. and does not require a brake …no matter what position I stop the motor the door cannot move.…no matter if the boat-lift gears fail …the door simply holds it’s present position. It’s 120-volt 1/2 hp motor that my portable generator can operate in the event of power failure. The only drawback is it takes 3 minutes for the door to fully open or close. As I’m never in a hurry to get anything out of the hangar that poses no issue for me.
It’s a 44’ wide door…so the cables picks up the door at 11’ from each end…. creating a balance such that the door cannot sag or bend if horizontal…..but further, I made the entire framework out of 11-ga 2” X 6” rectangular-tubing….and doubled the pickup point tubing to act as a “spar”. The pickup point is 14” below center so the top of the door automatically swings into the hangar when the cables pick it up. Each end of the 14’ H door has a steel wheel (ordinarily seen on side-moving rolling doors sitting on tracks) which is captured in the door-opening/uprights …it being made of I-beam…so the wheels are “captured” within the web of the uprights. This prevents the door from moving In or Out regardless of wind… and the wheels rest on stops built into the I-bean webs so the door, when closed, is supported on those wheels…and allows the (now bottom-heavy door because of the pivot-point-wheels being 7” above center)… the door automatically closes completely via gravity. Now that the door is closed…even a high wind does not move the door because of that high-center position of the end-wheels.
When fully open, I lose only 7” of height (the thickness of the door and it’s R-panel/trim.)
The door‘s top is held inside the hangar via trolley-tracks (usually used for sliding barn doors). Since the door’s weight is primarily held by the boat-lift/cable system, only about 150 lbs of weight is held by the trolleys…rated at 600 lbs each…time two trolley-tracks. (Yes, I’m fond of overbuilding, especially something that’s going to be over my head.)
Since the boat-lift operates by a set of 3 cables (any one of which is over twice the capability of the door weight) and those cables are counter-wound around a pipe-spindle… very little stress is placed upon the building.
I also added a “slave” cable …a closed-loop which operates as an auto-stop system… using ordinary cable clamps and a gate-hinge…so when the door reaches it’s travel limits…a pair of switches (in series for redundancy) open the motor electrical supply circuit…to stop the door. To override that system …to “start” the door in-motion… I used the push-to-start switch from a junk clothes-dryer, which momentarily energizes the motor to move the door off it’s stop-switches… When the door reaches the other end of it’s travel the stop switches are re-engaged.
Of course, I can …and usually do…. stop the door in half-way positions as desired. (Kinda fun to sit beneath that canopy in a rain and enjoy coffee or a beer with the dog. The wife thinks I must really be accomplishing something important out there.)
I made weather-seal out of 12” wide EDPM rubber folded in half, held in-place by the R-panel fasteners. I found the material in Houston in 45’ lengths.)
This was all accomplished in 2004, and I’ve had zero issues with it.
Here’s a few pics:

 

[jyoutz]

I did that door on my own. I went without a door for two years and spent the time with a lawn chair and beer visualizing it before coming up with the final design.
My intent was to avoid the problems of bi-fold doors (loss of overhead/height) and of hydro-swing doors (hazard of wind when open…. which both types suffer.) I also did not like the idea of side-rolling doors (didn‘t want the physical effort to open/close them…nor have them subject to the danger of collapse due to wind. Saw that at the airport one day when a storm “inflated” a hangar and dropped the door onto ‘planes and trucks stored inside for protection from that very storm.)

I wanted the door to withstand wind regardless of position. I also didn’t like the cost plus shipping plus installation of the other types.
I ended up with this idea…using a common boat-lift …and SS cable rated at 7K working load… in triplicate…which provided a good safety-margin …(door weighs 2400 by calculation of materials)…. and does not require a brake …no matter what position I stop the motor the door cannot move.…no matter if the boat-lift gears fail …the door simply holds it’s present position. It’s 120-volt 1/3 hp motor that my portable generator can operate in the event of power failure. The only drawback it it take 3 minutes for the door to fully open or close. As I’m never in a hurry to get anything out of the hangar that poses no issue for me.
It’s a 44’ wide door…so I the cables pick up the door at 11’ from each end…. creating a balance such that the door cannot sag or bend if horizontal…..but further, I made the entire framework out of 11-ga 2” X 6” rectangular-tubing….and doubled the pickup point tubing to act as a “spar”. The pickup point is 14” below center so the top of the door automatically swings into the hangar when the cables pick it up. Each end of the 14’ H door has a steel wheel (ordinarily seen on side-moving rolling doors sitting on tracks) which is captured in the door-opening/uprights …it being made of I-beam…so the wheels are “captured” within the web of the uprights. This prevents the door from moving In or Out regardless of wind… and the wheels rest on stops built into the I-bean webs so the door, when closed, is supported on those wheels…and allows the (now bottom-heavy door because of the pivot-point-wheels being 7” above center)… the door automatically closes completely via gravity. Now that the door is closed…even a high wind does not move the door because of that high-center position of the end-wheels.
When fully open, I lose only 7” of height (the thickness of the door and it’s R-panel/trim.)
The door‘s top is held inside the hangar via trolley-tracks (usually used for sliding barn doors). Since the door’s weight is primarily held by the boat-lift/cable system, only about 150 lbs of weight is held by the trolleys…rated at 600 lbs each…time two trolley-tracks. (Yes, I’m fond of overbuilding, especially something that’s going to be over my head.)
Since the boat-lift operates by a set of 3 cables (any one of which is over twice the capability of the door weight) and those cables are counter-wound around a pipe-spindle… very little stress is placed upon the building.
I also added a “slave” cable …a closed-loop which operates as an auto-stop system… using ordinary cable clamps and a gate-hinge…so when the door reaches it’s travel limits…a pair of switches (in series for redundancy) open the motor electrical supply circuit…to stop the door. To override that system …to “start” the door in-motion… I used the push-to-start switch from a junk clothes-dryer, which momentarily energizes the motor to move the door off it’s stop-switches… When the door reaches the other end of it’s travel the stop switches are re-engaged.
Of course, I can …and usually do…. stop the door in half-way positions as desired. (Kinda fun to sit beneath that canopy in a rain and enjoy coffee or a beer with the dog. The wife thinks I must really be accomplishing something important out there.)
I made weather-seal out of 12” wide EDPM rubber folded in half, held in-place by the R-panel fasteners. I found the material in Houston in 45’ lengths.)
This was all accomplished in 2004, and I’ve had zero issues with it.
Here’s a few pics:

Probably the best engineered shop door anywhere.

 

[GeoHorn]

Probably the best engineered shop door anywhere.

Better or more complete description/pics are available when I first posted at a different forum:

Hangar Door - The International Cessna 170 Association

 

[skeets]

GeoHorn,,, did you spend some time at your local airport comming up with that door

 

[GeoHorn]

GeoHorn,,, did you spend some time at your local airport comming up with that door

This hangar/door is on my own property. I never saw any door like this one anywhere, although in Tyler Tx I saw a door which opened by tilting inward simultaneously while raising …but it had complicated curving overhead tracks and hydraulic operating system. In Seattle I saw a wooden hangar door which opened on swing-arms with a homemade cable/winch device like a very large overhead garage door from the 1950s , but that door was very crude, sagged, and was only 30’ wide and 10’ tall for a small puddle-jumper.

My light-bulb went-off while I was at the lake and saw a boat-lift use cables to lift a boat, similar to this one pic’d below. I only needed to add two more sets of pulleys/sheaves to re-direct the cables out over the door-opening-header to complete the idea.

I had friends/family suggest I should patent or otherwise protect the design-idea, but over 20 years ago I posted the plans on the internet at an aviation webpage…so even if the idea were capable of being protected …(and I seriously doubt it)…. publishing it on the internet would kill that idea. Anyone desiring to do something similar can see my materials list at the link posted previously.

Another pilot (U.S. Air Force) up in Wichita Falls (Sheppard AFB) was needing a door on his open hangar but he was limited in space due to adjacent hangars and couldn’t use any door that opened to the side which would block access to the other hangars… and he had a limited budget (as anyone who’s been military understands that problem)…. so he came down and we designed an alternate plan for him that used the boat lift in a different orientation which reduced the operating-system size so it could fit inside a flat-roofed bldg. He made his door out of 2” square tubing because he thought I’d overbuilt my door. It worked out for him…but he only had that hangar two more years and was re-assigned…so I don’t know if the subsequent owner found any deficiencies in the lighter structure or not.
Wind loads, even on a closed door, can be considerable with a door this size, so I didn’t want to be marginal on strength.

 

[GeoHorn]

The entire cost (not including my labor and the BBQ & Beer for my two buddies who helped me) for materials was about $1700 in 2002. It’d probably be another $1K due to steel prices these days. The boat lift (7500 lb rating - more overkill) was only $300 and the cable (spool of 500’) was bought surplus at $200. I only needed 150’ of cable…still got the rest I’ve been using for other projects and in-case I ever need to replace any. I inspect everything and grease the sheaves (pulleys) every year. No problems or excessive wear yet. (I had expected to have to replace the 3/4” Grade 5 bolts being used for sheave-axles by now but they show hardly any wear marks at all.…which confirms for me that this is all a low-stress design.)
The only replacement made so-far was at 15 years I replaced the single V-belt at the motor, primarily out of an over-abundance of caution.

Here’s a pic of the boat lift motor/gearbox/spindle installation: