To design a metal building (without a hangar door) coordination is needed to get the correct code and loads on the metal building for it to be engineered correctly and also coordination is needed to get the anchor bolt reactions correct so that the foundation is formed for the least amount of concrete for the intended use of the metal building.
For a metal aircraft hangar all of the above requirements still applies but now 1 or more huge doors need to operate on and hang from the frames.
When a call comes in to design a hangar we start with the door. We ask the size and style of the door they would like, meaning “is it a bi-fold, where it will fold up to a wedge?” or “is it a hydraulic style where it tilts up from the front of the building?” Those 2 options are the most common. Other options are a rolling door that would roll on the ground or a rolling door that would hang from tracks?” There are also some exotic tilt types but we rarely see them.
For an example we will use a bi-fold because we mostly design buildings for that type of door. The most important thing with a hangar is to figure the hangar door opening size carefully. You need to estimate the needed size opening for any future airplanes you might acquire for the most use. Take for example if we figure a Cessna T210F Turbo. The wing span is 36’ 6” (11.13M) and the height is about 9’ 8” (2.95M). If you are trying to estimate a door size always figure more not less. I feel for this aircraft a good hangar door size would be about 46’ by 12’. You can find aircraft sizes on our web site HangarBuildings.com and the sizes link is at http://www.hangarbuildings.com/sizes.html
Going on with our example, if we figure the width at 46’ the math would work out to be 46’ – 36’ 6” = 9’ 6” and if you take the 9’ 6” of free space and divide it equally on both sides it would 4’ 9” on each side from the wing tips to the building structure. That seems easy. I think if you had to you could easily fit a little larger aircraft in the same hangar although you would need to take more care clearing the wings on each side.
The height is another matter. If you run the straight math it works out to 12’ – 9’ 8” = 2’ 4” which seems easy. But what a lot of people do not think of is that when you pull out your aircraft nose first, if it has a tricycle gear like the Cessna 210, it all depends on the slope of the front apron of concrete right in front of your hangar. If the slope is small for drainage the tail will only swing up a little. If the slope is greater the tail will swing up a lot. It is hard to figure the math until it is built but for designing the hangar we usually recommend plenty of room so that tail of the aircraft you are designing for will easily clear the tail with a standard slope.
Another thing to think about when designing a hangar is the overall height of the building. The FAA has some rules about building close to a runway. They use a sloped line from center line to figure maximum height. You might want to confirm your buildings works within that height.
For overall height when designing a building I figure the needed door height + door wedge + 1’ of building trim. The door wedge is determined from a table according to width and other factors and if it is a hydraulic style it is only about 9”. For our example it would be 12’ + 3’ 6” wedge (for that door) and 1’ building trim to equal 19’6“ tall at the sidewalls. The slope of the roof does not matter much although 1/12 is usually the least cost.
Once we have the information of the door size, the code and loads and zip code for delivery we are ready to design. For our example we would start with an overall building size of about 52’ (46’ opening + 3’ on each size for frames) by 40’ (our Cessna 210 is 28’ or 8.53M long) by 19’ 6” tall as explained earlier.
We would then set the frames, girts (wall framing) and purlins (roof framing) like a standard pre-engineered building but then we would add another main frame just behind the left end wall to hold the weight of the door. Then from that frame we would hang stub columns that would hang down to catch the top of the door spaced for the hinge points of the door. Once a hangar door is installed and opened the force (moment force) on the building as it hangs out front is huge. So hangars use back braces. For our back braces we usually use 6” pipe from the second main frame back to the bottom of a couple stub columns. This makes for a very solid design and a good looking building you can be proud of.
It is critical that whoever designs your hangar understands the coordination needed to make sure the door fits together on the building and works correctly once installed. We prefer to work with Schweiss Hangar Doors (bifold.com), although, we can design for any door.
On our example, from the person that called who needed a hangar for a Cessna 210. We have preliminarily designed the building from our tables of door sizes, wedge sizes and standard door layouts for costing but now the builder or owner is ready to purchase the building. They need to do 2 things, commit to the hangar door supplier and confirm we have loads and codes correct for the design – because they are always changing. Once that happens Schweiss (or your door supplier) would send us the door engineering for that exact door that they are building for that hangar at that location. We take that engineering and detail the building to fit that door exactly. We adjust the hinge points, the weight and the exact overall measurements so that the door will roll up and down on our beams correctly.
When you are getting quotes for hangars note if the supplier or designer has included the panels, fasteners and trim for the hangar door also. When the door supplier sends us the engineering for that specific door it also has trim and panel details. So make sure when you note the colors you want on your building that the door panels and door trim are colored as you would like.
In this example I have explained a single stand alone hangar. There are endless possibilities of building hangars into other type buildings like homes, offices, FBO’s or long multi unit T-style hangars where the partition walls define hangar spaces and hangar doors would hang from large beams on the sidewalls.
If you need a hangar, let’s design one together.
We make it easy!
Larry Stevens