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Hunting for a Home: Experiences Searching for a Hangar

Hunting for a Home: Experiences Searching for a Hangar

“It’s impossible to find a hangar anywhere,” was the refrain every pilot around me sang, but within a month my new plane had a roof over its wings. Was it just luck? No matter how I acquired my hangar, it seems they are in short supply around here. “Here” being northern New Jersey, a modest drive west of New York City, but pilots from around the country seem to sing the same song.

There are many airports around here, from Newark Liberty International Airport (KEWR), which would be a preposterous base for an aircraft unless you own a Fortune 500 company and your aircraft is a multimillion-dollar jet, to grassy airstrips visited only by the taildragger crowd. 

Fortunately, New Jersey really is the Garden State, just like it says on the license plates. Once you get a few miles from the I-95 corridor there are abundant, small and friendly airports west of NYC and north of, let’s say, Princeton. Even Charles Lindbergh built an airfield on his New Jersey estate. Many of these small airports are set amid rolling farmland and some of the most idyllic scenery in the country.

After visiting a number of these airports, I found the hangar facilities fell into three categories.

1. Common hangars

One airport offered only a single common hangar that housed about 20 airplanes and helicopters, from Cessna 172s to a Learjet. With so many different types and sizes, a pilot really needs to rely on the airport staff to pull out his plane, which might not be possible outside of working hours. Or your plane could be waiting for you on the tarmac if you call ahead—and fueled up, too. 

Most of my friends shuddered at the prospect of serious “hangar rash” with so many aircraft being moved around. Also, there may be little security. I’d never leave my headsets or portable GPS in that sort of hangar. 

I doubt if an owner could do much maintenance either, maybe just a simple oil change. You might be allowed to keep a small tool box along a wall, but the airport management would certainly not be responsible for any loss of that either. 

Common hangars usually have some space available and are often the cheapest roof over your plane.

2. Shared hangars

Another airport had a couple hangars to share, big enough for three or four airplanes, but with no space available. This situation is better than a giant common hangar, as a tenant would get to know the other aircraft and how to move them if needed. 

There’s still a risk of hangar rash, not just from moving aircraft. I can see even the most careful pilot twanging a wing with a broom handle while cleaning up. 

Shared hangars are more expensive than a common hangar, but are more secure, with only the aircraft owners having access. It could be a social environment, too, which is good if the other pilots are responsible and fun people—or a nightmare if your hangar partners are a bunch of slobs.

3. Private hangar

This is the way to go if you can afford it, and these are the ones impossible to find. Of course, the owner(s) of a single aircraft have to pay all the rent, but at least they can control the use of their hangar.

Private hangars have many advantages:

• Security—Keys to the hangar and access to the plane are limited. You can lock up your headsets, flying and maintenance gear, including tools.

• Storage—Although the FAA is cracking down on “non-aviation uses” of hangars, especially at airports that receive federal funds, there’s room to store some stuff. An FAA investigation found hangars that held cars and boats, with nothing related to aviation, and they believe this takes space from people who actually want to house a flyable aircraft. Items stored in a private hangar should have some association to aviation, such as tools, aircraft skis or floats, covers, oil and other aircraft maintenance items.

• Workplace—For homebuilders, a hangar may be primarily a construction site. The FAA is not completely on board with the idea of a hangar being used to build a plane, when so many people need space to store flyable aircraft. Using a hangar  (sometimes for years) for a plane that doesn’t need the access to runways is a real issue.

• Maintenance—I’ve seen workshops of varying complexity in hangars, from a small box of tools to a full machine shop. Having a private hangar allows owners to pull apart their plane and leave the parts spread across the floor, whether for an oil change or an annual inspection.

• Social—Hangars can be a simple slab of concrete surrounded by tin to protect your airplane from the worst of nature’s elements, or it can be the ultimate recreational space. All pilots know that the coolness of an individual’s personal space is increased exponentially when an aircraft is parked within. (“You’ve got a pool table in your man cave? Bah! I have a P-51.”) Hangars are places where pilots can gather to relax, drink and talk flying.

Other cost factors

Besides the cost differential of common versus private hangars, I found prices were driven by a few other factors.

1. Location—With proximity to a large city, or a suburban town where big-city big shots live, the greater the price of hangars. No surprise there, especially if half the airport is used by business jets. 

2. Amenities and upkeep—Hangars are as scarce as hen’s teeth at those beautiful, almost park-like airports, with neatly cut grass, a restaurant and a thriving community of pilots. Other airports only offer ancient, drafty, tin hangars with rusty doors, potholed runways and muddy taxiways. You get what you pay for.

3. Subsidies—One of the airports I considered was a state property, and the rental rates were the lowest around; your tax dollars at work. But, of course, they had no space available.

“Are you one of us?”

Does social politics play a role in who gets a hangar? Do taildragger airport managers scoff at nosewheelers? I wondered, as pilots at a particular airport would say, “Yeah, the manager told me there were spaces available,” but when speaking to that manager, “Unfortunately, there aren’t.” 

Then, an instructor would say, “Yup, he told me yesterday there was space available,” but when asked again, “Sorry, we’ve got no space.” 

Is it the pilot or the plane? I kept hearing, “We’d love to have your airplane here.” Is he more interested in the airplane than the pilot? Do the managers want only the coolest aircraft at their field? I suppose anything’s possible.

No doubt, if a pilot’s reputation as a troublemaker precedes him, I’d want the manager to claim there’s no room, too. I hope I’m not that guy.

No room at the inn

When all options fail, you may have to tie down your aircraft outside. If your airplane is worth any amount greater than the average car, it really deserves protection. 

But, without a roof over your plane you should invest in a full set of wing and fuselage covers, engine plugs and pitot tube covers. Reflective shields will protect the interior from the summer sun, helping to slow the inevitable cracking of plastic and vinyl, and perhaps extending the life of your avionics, too.

The only advantage of a tiedown over a hangar is cost—as little as $50 per month—but you get what you pay for. Usually, that’s just a square of grass (if you’re lucky) or mud, and perhaps a concrete anchor to tie down your plane. 

Place some metal grid or industrial rubber matting on your tiedown spot if you don’t want to wear a muddy hole in the ground where you climb in. Most pilots buy a locker to hold a small ladder, cleaning supplies and oil, and place it alongside their plot. (You’ll want the locker to store your covers while you’re out flying, too.)

If you tie down, be prepared to shovel snow or be grounded. Most airports can’t remove snow from grassy tiedown areas, and when the snow melts you still may not be able to taxi over the soft ground. A heavy rainstorm might also keep you mired in mud.

For more cash you could get a tiedown on tarmac, which is better than a muddy spot and will usually be plowed after snowstorms. You’ll still have to deal with rain-soaked aircraft covers, bird droppings, frosty wings and muddy feet in your cockpit. You’ll also worry when there’s a forecast for hail in the area, and need to be wary of birds and bugs building nests in any available nook of your plane. 

As in a common hangar, tied-down aircraft are not very secure. Any theft from a plane that I’ve heard of, usually a headset or GPS, was from a tied-down plane.

Tied-down aircraft cost a little more for insurance, too. Avemco, for example, gives a 10 percent discount on the hull coverage premium if you hangar your aircraft. That’s due to the number of claims from on-the-ground weather incidents, such as hail damage. All in all, hangars are better.
Beggars can’t be choosers

If you have few options, you’ll have to take the best you can get, as-is. I’m very happy with the airport I found, and feel lucky to have found a hangar there. It’s a beautiful spot, with a friendly group of pilots, a wide variety of aircraft, an EAA chapter and a pretty good restaurant. 

I think my good fortune was just the luck of timing. It was autumn when I needed my space, so I think some pilots had sold airplanes and moved out during the summer.

However, there are a few items that my hangar lacks, which could be worth keeping in mind during your hangar search.

1. No running water, not even a hose faucet anywhere along the row of hangars. I can’t hose out the hangar or wash my plane, or even fill a bucket to do some cleaning.

2. My hangar has only one electrical outlet. I need to run a 40-foot extension cord to get power anywhere else in the space. A few more outlets would have been convenient.

3. The hangar has a small lip from the concrete floor to the tarmac. This seems really minor, but it can be a struggle to push my plane over that by myself. I did install a couple metal ramps, but it’s still a pain.

4. If I had my choice, I would have picked a south-facing hangar. Mine is in the shade all winter, and significantly colder than the ones across the taxiway. On a chilly but sunny winter day, those hangars get almost toasty.

Finding a hangar for your airplane can be more difficult, with fewer choices, than finding a home for yourself. And there are no realtors to help. If you’re thinking of buying an aircraft, start early to explore the airports in the area where you’d like to fly. 

Talk to pilots hanging around the airports, look over the facilities and let people know you’re in the market. A guy who knows a guy who’s thinking of moving out of his hangar could put you in the right place at the right time to find the right home for your plane.

Dennis K. Johnson is a writer and a New York City-based travel photographer, shooting primarily for Getty Images and select clients. He spends months each year traveling, flies sailplanes whenever possible and is the owner of N105T, a newly restored Piper Super Cub Special. Send questions or comments to .

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The Best Entry-Level Pipers

The Best Entry-Level Pipers

Longtime Piper pilot and Piper twin owner Kristin Winter discusses the cream of the crop in entry-level VFR Piper aircraft.

Photos by James Lawrence

My introduction to flight came in a Cessna 152, in which I did most of my primary training. As a leggy Norwegian from the Upper Midwest, it was not a great fit; it was a barely fit. Add springtime convective turbulence and a flight school that had us plan all of our cross-country flights at 3,000 feet, and that poor little Cessna and I never quite hit it off. I learned what airsick was before I learned what airspeed was. 

A chance flight in a Piper Arrow II transported me upward in my eventual flying career—in more ways than one. I was smitten with the solid stability of the Arrow even in our brief dalliance. (For details on this flight, take a look at “Saved by the Arrow,” published in Piper Flyer in June 2016. —Ed.)

After passing my private pilot checkride, I cast longing looks at the two Arrows nestled among the gaggle of Cessna 152s and 172s. Unfortunately, the evil stepmother in this fairy tale—in the person of the FBO manager—decreed that I must have 100 hours before I could snuggle into one of the Arrows without a chaperone. This sent me in search of something similar that satisfied my urge for stability.

Discovering the Piper Cherokee 140

Back in the 1970s, there were seven FBOs on this suburban airport, a condition unheard of in the 21st century. A couple of hundred yards down the taxiway was a small FBO owned by a long-term instructor and airline pilot. 

For a reasonable price, there I could explore the charms of what I consider the best entry-level Piper for local flying and short cross-country flights: the PA-28-140, commonly known as the Cherokee 140. 

Here was a pair of 1967 models sporting Mark 12 navcoms, the greatest tube navcoms ever made. (For those less fossilized than myself, glowing vacuum tubes were what powered electronics until transistors and other solid-state circuitry took over a few years after these aircraft were produced.) One of the 140s had a coffee grinder-style ADF that required the pilot to carefully tune and listen for the ident to have any hope of finding the right frequency. 

For night flying, the instrument panel was lit by a red floodlight on the ceiling, just behind the trim crank, which was also on the ceiling and looked like a window crank from a 1950s Chevy (and probably was). It was perfect. I felt like I had stepped into an Ernie Gann novel. 

I put at least a hundred hours on those two planes as I forged toward my instrument rating, which was back when one needed 200 hours to qualify for it. I have flown numerous 140s since, and they are honest, straightforward little airplanes.

 

Production notes

The Cherokee was the replacement for the Tri-Pacer. It was designed to be simple to fly, simple to manufacture, and simple to maintain. This new model also got a new home as Piper opened up a factory in Vero Beach, Fla., which has been the home of the Cherokees and their derivatives ever since. 

Originally the aircraft was produced in 150 and 160 hp models and was called the Cherokee until the 1963 model, when it became the Cherokee B. With the B model, the buyer could choose a 150 hp engine, a 160 hp engine or a 180 hp engine. For the 1965 model, it became the Cherokee C, with the same engine options as the Cherokee B.

The aircraft got its “Cherokee 140” moniker when Piper decided to promote the basic Cherokee as a trainer. Piper removed the rear seats and tweaked the prop, and Lycoming tweaked the engine slightly to reduce the horsepower from 150 to 140 hp. 

The PA-28-140 came out in early 1964. In 1965, the horsepower was upped back to 150 and it was offered with rear seats. (Piper sold a kit to add the rear seats to the 140s sold a year earlier.) About the only thing that remained was the name. 

For 1964 and most of 1965, buyers could purchase a Cherokee 140 with 140 hp and thereafter, with only 150 hp engine as an option. From 1964 through 1967, buyers could also get a Cherokee B or Cherokee C with their choice of a 150, 160 or 180 hp engine. 

It was a confusing mishmash of models that Piper simplified with the 1968 model year, when the company trimmed the offerings to two: the Cherokee 140 with the 150 hp engine, and the Cherokee D with the 180 hp engine.

The Cherokee 140 did not undergo too many significant changes over its run, which ended in 1977. The most notable changes included going from push-pull engine controls to a throttle quadrant; a standard “T” configuration instrument panel; and moving the pitch trim from the overhead crank to the wheel on the floor next to the Johnson bar for the flaps. 

Various minor and cosmetic changes and refinements were made too, but these Cherokees are all the same basic airplane and they all fly the same way. Cherokee 140s were kept simple on purpose, as they were aimed at the trainer market and designed to keep the hundreds of Piper flight centers equipped back in the heyday of General Aviation training and activity. The production run only ended when the Tomahawk was introduced as the new Piper trainer.

Flight characteristics

If I had to describe a Cherokee in one word, it would be “honest.” They are simple and straightforward to fly, to land, and to maintain. In smooth air they can be trimmed to hold altitude so well you would think it was on autopilot. 

For northern pilots, it is nice that Cherokees are warm in the winter. The heater and the insulation are adequate to keep the cabin comfortable, even when it is below zero outside. 

They pretty handle well in a crosswind due to the low center of gravity and the wide stance of the landing gear, though the roll response is not stunning. The manual flaps also give you instant and immediate control, so if one needs to dump lift after touchdown, it is easy and quick.

I have a blast flying Cherokee 140s, but never flew one that had 140 hp. I doubt any that were made have not been converted to 150 hp. My first choice for an entry level, VFR, fun airplane that is a realistic option for a 200- to 300-mile trip carrying a couple of passengers would be a Cherokee 140. 

Cherokee 140 considerations

Today a Cherokee 140 can be had for the price of a new Toyota. It would be hard to spend more than $40,000 on one, and many are available for $30,000 or less.

Maintenance is simple and annual inspections should not much exceed $1,500 even in an expensive part of the United States, provided the aircraft is maintained as it goes and flown regularly. 

It is also one of the cheapest aircraft to insure, even for low-time pilots. At 7 to 8 gph, fuel burn is reasonable and the aircraft can be STC’d for auto fuel if it is available in one’s area.

Most Cherokee 140s will have a useful load around 820 to 850 pounds, which means you can fill the tanks with 48 gallons of useable fuel and still put almost 600 pounds in the aircraft. That makes it a good three-person aircraft, though there are some limitations on back seat legroom. 

At maybe 110 ktas burning about 8 gph, it has on-paper a range of around 450-plus nm with a VFR reserve—though backseat passengers might not be able to stick it out for four hours. Three hours is a reasonable maximum for these planes, yet they are also an economical choice for local flights and the proverbial hundred-dollar hamburger run.

 

The PA-38: also a good choice

My second choice for an entry level VFR aircraft might surprise some. I will make a pitch here for one much-maligned Piper, suitable for those who only need two seats. The Tomahawk is a very nice little plane. I have hundreds of hours in them. 

The poor Tomahawk got a bad rap as the tail structure needed some beefing up and a few pilots got them into a spin that they couldn’t get out of. 

Of all the planes I have flown—which covers most everything Piper has made in the last 50 years—the Tomahawk is the most fun just to do touch-and-goes. There is no other airplane that I can consistently grease on the runway than a Tomahawk. 

It is also just a fun little airplane, if you stay off soft strips. It would be a good choice to learn to fly in and to just bop around in. The visibility is unmatched with the bubble canopy and the panel is logical and well-laid-out.

The Tomahawk was designed as a trainer, so don’t expect it to be a great traveling machine. As it happens, I have flown as much as 400 nm in one leg, which is about as far as its 30 gallons of fuel will take it. It will cruise between 100 and 105 ktas burning 6 to 6.5 gph. 

The Tomahawk deserves a more complete treatment than I can give it here. There is nothing intrinsically wrong with the little Tomahawk, despite disparaging names like “Traumahawk,” typically uttered by pilots who have never flown one. It is by far my favorite two-place trainer, and I would love to have one just to go around the patch and do touch-and-goes.

 

Compare and contrast

The Cherokee 140 and the Tomahawk are two excellent starter aircraft for VFR or light IFR, if properly equipped. 

The 140 has more capability and is more expensive to buy and feed gas than the Tomahawk. There are also a lot more of them out there. For that reason, the Cherokee 140 gets my nod over the fun little Tomahawk, which is somewhat rarer to find in the market. 

Both of these airplanes are great entry level choices for a first-time buyer looking for an economical plane for fun local flying and short trips. 

Look for Winter’s further explorations of the best Pipers for other missions in future issues of Piper Flyer. —Ed.

Kristin Winter has been an airport rat for almost four decades. She holds an ATP-SE/ME rating and is a CFIAIM, AGI, IGI. In addition, Winter is an A&P/IA. She has over 8,000 hours, of which about 1,000 are in the Twin Comanche and another 1,000 in the Navajo series. She owns and operates a 1969 C model Twinkie affectionately known as Maggie. She uses Maggie in furtherance of her aviation legal and consulting practice; she also assists would-be Comanche, Twin Comanche, and other Piper owners with training and pre-purchase consulting. Send questions or comments to .

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Installing Shoulder Harnesses

Installing Shoulder Harnesses

Adding shoulder harnesses in at least the front seats should be a must for any aircraft that does not have them. A&P/IA Kristin Winter reports on the recent installation of a three-point system on an aircraft that previously had only lap belts.

Before the early 1970s, Piper did not provide shoulder harnesses for its aircraft. In fairness, that was only slightly after the auto manufacturers did the same thing. 

Lack of shoulder harnesses have resulted in life-altering brain injuries from accidents in which the front seat occupants could have walked away virtually unharmed. Fortunately, a number of companies have STCs for the retrofitting of shoulder harnesses in Piper aircraft. 

Several retrofit options

The largest manufacturer of restraint systems is AmSafe. It supplies much of the OEM market, be it a GA manufacturer or a commercial aircraft manufacturer like Boeing. 

The only product AmSafe currently offers as a GA retrofit is its seatbelt airbags. (Winter has a set of seatbelt airbags she plans to install in her Twin Comanche, and will report on that project in a future issue of Piper Flyer. —Ed.)

The largest holder of shoulder harness STCs for Piper aircraft is Alpha Aviation in Minnesota. Alpha Aviation has STCs covering early PA-23, PA-24, PA-28, PA-30, PA-32 and PA-39 aircraft. 

B.A.S. in Washington has an STC for the PA-28/32/34. The kit offered by B.A.S. is a four-point shoulder harness/lap belt system. 

Aero Fabricators, a company affiliated with Wag-Aero, has several STCs as well. Wisconsin-based Wag-Aero offers kits for J-3, PA-11, PA-18 and PA-20/22 aircraft, as well as PA-28s. 

Univair in Aurora, Colo. markets AmSafe shoulder harness restraint systems for J-3s, PA-11s, PA-12s and PA-18s.

A brief look at the kits

Most of the STC kits have two sets of components. One is the belts and fittings. 

Some shoulder harnesses have inertia reels, and some include a fixed belt. The latter type generally costs less, but can be a bit less convenient for the pilot when he or she has to loosen the belt in order to reach something in the cockpit. 

The other set of components in a kit is whatever is required to provide the necessary structure in order to mount the shoulder harness with enough strength to provide the necessary protection to the user. 

This typically involves some reinforcements that need to be attached to the fuselage, usually involving riveting. For that reason, this is not a project for an owner alone unless he or she possesses an A&P license and the tools necessary for the job. 

In addition, a shoulder harness installation constitutes a major alteration, and requires that an A&P/IA inspect and sign an FAA Form 337.

Required tools and supplies

The tooling necessary to complete this project will vary a bit depending on what structure is required. Some airplanes may already have the structure installed because shoulder harnesses were an optional item for that particular model year; others may need quite a bit of reinforcing pieces installed in order to provide the necessary support. 

Regardless of the kit, the tools necessary for installing solid rivets—and possibly blind rivets as well—will be a necessity. 

Any practicing A&P is likely to have the necessary tooling, but for an owner that is interested in participating and wants his or her own tools, the major item is a 2X rivet gun. U.S. Industrial Tool, Sioux Tools and Chicago Pneumatic are just a few of several rivet gun manufacturers. 

The most important part of the rivet gun is a good “teasing” trigger that lets the operator control the force and frequency of the blows. The gun also needs a rivet set, which is the part that actually touches the rivet, and a spring retainer to hold it to the rivet gun. 

In addition, a selection of Cleco temporary fasteners and pliers will also be necessary. 

It goes without saying that the ability to drill holes will be key. A #30 drill bit is used for a 1/8-inch rivet and #40 is for a 3/32-inch rivet. There are some excellent YouTube videos done by EAA on the basics of sheet metal work. (See Resources for additional information. —Ed.)

This is a project that any owner with mechanical aptitude can tackle with supervision by an A&P. Doing so will be a great learning experience for those interested in understanding more about what is involved in aircraft maintenance.

A Comanche 250 project

Recently I participated in, inspected and signed the Form 337 on the installation for a 1959 PA-24-250 Comanche which had never had shoulder harnesses installed. The new owner was keen to have the safety advantage of shoulder harnesses. 

The Alpha Aviation kit for the Comanche 250 was very complete and of excellent quality. (See photo 01, page 22.) The kit included all required parts and hardware including restraints for two front seats, an 8130-3 Airworthiness Certificate, an installation manual and a copy of the STC and signed STC authorization. 

First steps

The first step is to gently remove the headliner from the area to provide access to the structure above the rear window. (See photo 02 on page 24, top.) Removing the headliner can be a challenging project and needs to be undertaken carefully to avoid damaging the headliner.

The structural portion of the kit consisted of a stringer and two doubler plates. The two doubler plates are riveted together with a carefully-laid-out pattern, and to this doubler plate assembly is mounted the attachment point for the inertia reel for the shoulder strap. Then a longitudinal stringer and the assembled doubler plate must be fitted and riveted to the airframe above the rear window. 

 

Measuring and positioning 

Careful measurement is key to making sure that the stringer and doubler are properly positioned. This is done by riveting the bottom of the assembled doubler to the existing stringer that runs above the window, as shown in photo 03 (page 24, bottom). Note that blind fasteners were used here. 

The installation of the assembled doubler sets the position for the new stringer, which runs from the door frame back to the frame at the back bulkhead. 

The photo below shows the assembled doubler and the stringer fitted to the aircraft and held in with spring sheet clamps, referred to colloquially as Clecos. Clecos have been used since before World War II and are indispensable for aircraft sheet metal work. The most common type require a special set of pliers to install and remove them. 

 

Clecos are color-coded based on the size of the hole they are designed to fill, and are used to pull tight the two sheets of metal. As mentioned earlier, there are several good videos available from EAA that cover Clecos and other basic sheet metal techniques and tools. 

The temporary fastening process

As is good practice, the initial holes were drilled to a smaller size, in this case 3/32 inch, which later were enlarged to 1/8 inch as called for in the instructions. This technique works to clean up any shifting that takes place so that each hole is reasonably precise. 

Once the structure is fitted and all the holes are drilled, the parts are removed in order to clean off the burrs and excess material from around the rivet holes. The parts are then reassembled and held in place with the Clecos.

Anchoring with rivets, and final steps

Solid rivets are generally preferred and more economical, but are not always practical, and the kit from Alpha Aviation provides both solid rivets and blind CherryMax rivets. 

CherryMax rivets are souped-up pop rivets made to an aerospace standard and are designed with a locking collar to fasten the stem into the rivet as the stem forms much of the strength of the fastener. 

CherryMax rivets are used when you can’t get a bucking bar to the back of a solid rivet. They can be seen in photo 04 (below) as they are used to attach the lower side of the assembled doubler to the aircraft’s existing stringer. CherryMax rivets have a number of special pullers that can be used to install them; some are hand-operated and some are pneumatic. 

Once all the rivets are installed, a strong support base has been created to anchor the inertia reel and shoulder harness, as shown in photo 05 (below). 

Reinstallation of the headliner, carefully cutting a hole for the bolt, and subsequently bolting on the inertia reel completes the installation—save for the log entry and completing the Form 337. 

 

Labor may vary; added safety will not

The labor necessary to install the shoulder harness kit varies with the amount of structure that must be added. It can take anywhere from a handful of hours to a couple of days’ worth of labor, but shoulder harnesses are most needed in the kind of accident that can happen to even the best pilots. 

No restraint will help if you hit a mountain at cruise speed—but landing mishaps, loss of runway control, or even a controlled glide into favorable terrain after an engine failure are more common. These scenarios are where a shoulder harness might make all the difference. 

Know your FAR/AIM and check with your mechanic before starting any work.

Kristin Winter has been an airport rat for almost four decades. She holds an ATP-SE/ME rating and is a CFIAIM, AGI, IGI. In addition, Winter is an A&P/IA. She has over 8,000 hours, of which about 1,000 are in the Twin Comanche and another 1,000 in the Navajo series. She owns and operates a 1969 C model Twinkie affectionately known as Maggie. She uses Maggie in furtherance of her aviation legal and consulting practice; she also assists would-be Comanche, Twin Comanche, and other Piper owners with training and pre-purchase consulting. Send questions or comments to .

RESOURCES >>>>>

Shoulder harness STCs
–PFA supporters
Alpha Aviation Inc.

 

B.A.S. Inc.

 

Univair Aircraft Corp.

 

The Wag-Aero Group

 

GA seatbelt airbags
AmSafe, Inc.

 

Fastening tools and supplies
Chicago Pneumatic

 

Cherry Aerospace

 

Sioux Tools

 

U.S. Industrial Tool & Supply Co.

  

Educational videos
EAA’s Sheet Metal Channel
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The Right Mix: An Aircraft Carburetor Overview

The Right Mix: An Aircraft Carburetor Overview

 

Many Piper aircraft depend on a carburetor. Piper Flyer contributing editor and A&P Jacqueline Shipe explains the operation of this fairly simple—and very reliable—invention.

One of the most recognized carburetor manufacturers for the GA fleet is Marvel-Schebler. The company has been around a long time, having its beginnings in the early 1900s when George Schebler and his friend Burt Pierce worked together to design the first carburetor using a tin can with a flap to regulate airflow. 

They both went on to patent their designs, with Pierce calling his carburetor the “Marvel.” Both the Marvel and the Schebler designs were successful and used on a variety of engine types. 

In the early days of General Motors, the two merged and became known as Marvel-Schebler Carburetor Co. (Author’s note: Burt Pierce also designed the still-popular Marvel Mystery Oil through Marvel Oil Co., which he founded in 1923.) In the beginning, the Marvel-Schebler Carburetor Co. made carburetors for cars, boats, tractors and airplanes. 

The company has since changed hands several times, being purchased and resold by Facet Aerospace Products, Zenith Fuel Systems, Precision Airmotive and the Tempest Group (who called it Volare Carburetors until it acquired the Marvel-Schebler trademark in 2010). Today, Marvel-Schebler Aircraft Carburetors LLC produces a complete line of aviation carburetors and parts.

Although Marvel-Schebler is the most recognized brand for aviation carburetors, there are other FAA approved manufacturers, including AVStar Fuel Systems in Florida. 

AVStar was formed in 2007 and has gone on to become the supplier for Lycoming Engines as well as numerous individual customers. AVStar manufactures a line of carburetors as well as kits and parts for use in almost all carburetor models in the General Aviation fleet.

 

 

 

How a carburetor functions

Aircraft engines rely on a steady source of fuel to provide the energy needed to support combustion. Liquid fuel must be vaporized and mixed with the proper amount of air in order to burn properly in the cylinders. 

Many General Aviation planes depend on a carburetor to provide a continuous, reliable source of properly mixed fuel and air to each cylinder. The aircraft carburetor has a relatively simple design and is typically very reliable.

Most aircraft carburetors are fairly straightforward in construction. A top part, called a throttle body, houses the throttle valve, mixture control and venturi; a lower bowl section, called a reservoir, holds a consistent volume of fuel. 

Almost all aviation carburetors are float-style carburetors. This means that a float mechanism regulates the fuel level in the reservoir (i.e., bowl). 

 


The float mechanism

The float is hinged on the rear, allowing it to pivot up and down. A pencil tip-shaped float valve is attached to the top rear of the float. 

Fuel enters the carburetor through the inlet screen, flows down through the float valve and its seat, and into the carburetor bowl. As the fuel level rises, the float and the attached float valve also rise until the float valve is implanted in the seat, shutting off the fuel flow. 

As the fuel level in the bowl drops, the float and float valve also descend, allowing fuel to once again flow into the bowl.

The float travel from full-up to full-down is relatively short; it is stopped on the descent by a tab on the rear hinge. The level to which it rises up is stopped by the attached float valve and seat. 

 


Adjusting fuel level

It is important to maintain a correct fuel level in the bowl. If the fuel level is too low, the engine will run too lean; if it is too high, the engine will run rich and fuel may leak continuously from the discharge nozzle. 

The fuel level is adjustable by adding or removing washers under the float valve seat to extend or lower it, or by bending a tab on the float itself at the point of contact with the float valve to extend or lower the valve.

 

 

 

Airflow

Airflow through the carburetor throat begins at the aircraft air filter and proceeds through the airbox into the throat of the carburetor. 

A venturi in the carburetor throat narrows the airflow opening, increasing the speed of the air, thereby lowering its pressure. (This is based on Bernoulli’s principle of airspeed and pressure being inversely proportionate; the same principle explains how an airfoil generates lift.) The outlet for the fuel discharge nozzle from the bowl is placed in the center of this low-pressure area. 

The air chamber on top of the fuel in the carburetor bowl is vented to atmospheric pressure. The pressure difference from the atmospheric pressure on top of the fuel in the bowl versus the low pressure on the fuel discharge nozzle causes fuel to flow out the fuel discharge nozzle. 

A throttle valve (i.e., a butterfly valve) located just downstream of the venturi controls mass airflow through the carburetor throat. As airflow increases, the suction effect on the fuel discharge nozzle also increases proportionately, allowing more fuel to flow. 

 


Fuel flow

Before fuel flows from the bowl out the fuel discharge nozzle, it is routed through the mixture control valve. The mixture control valve is attached to the mixture control arm. 

The mixture control valve on most models contains a shaft (also called a stem). The bottom of this shaft is shaped like a half-cylinder. It rotates in a cylindrically-shaped sleeve with an opening on the side. 

When the mixture is set at full rich, the open part of the shaft/stem is aligned with the opening in the sleeve, allowing full fuel flow through the valve and out of the nozzle. As the mixture control is pulled back to leaner settings, the opening becomes more and more narrow until it is completely closed at cutoff.

When the mixture control valve is open, fuel flows from the mixture sleeve through the main metering jet (this is a fixed orifice that controls the maximum amount of fuel allowed to exit the main discharge nozzle once the mixture control is set to full rich) and into the discharge nozzle well, where it begins to be mixed with air from bleed holes in the nozzle. From there, it flows up and out the main discharge nozzle and into the intake pipes for the cylinders. 

At low throttle settings with the throttle valve nearly closed, there is not enough suction on the main discharge nozzle to cause fuel to flow out of it, but there is a slight amount of airflow between the edge of the throttle valve and the wall of the throttle body. 

This small area of airflow around the edges of the throttle valve acts as a venturi, forcing airflow to speed up as it passes between the edges of the throttle valve and the carburetor throat and lowering the air pressure. 

In order to provide adequate fuel for idling, small openings are made in the throttle body in this area of low pressure. Ports connect the openings with the inner section of the main fuel nozzle and draw fuel from the nozzle at low throttle settings. This arrangement provides an adequate fuel supply for idle speeds. 

 

 

Idle adjustment

The idle speed and mixture are adjustable, and are the only two adjustments that can be made on most carburetors. Most planes should idle at speeds of 600 to 650 rpm. The idle speed adjustment is simply a stop screw that limits the rear travel of the throttle arm. (It screws in to increase idle speed; moving the screw counterclockwise decreases idle speed.)

The idle mixture adjustment is a large screw on the top rear of the carburetor that screws a needle closer to or further from its seat, which allows more or less fuel to flow through the idle passageways. 

The idle mixture is made leaner as the screw is turned in and richer as it is backed out. It should be adjusted so that there is a 25 to 50 rpm rise in engine speed when the mixture control is pulled all the way back to shut down the engine. 

If there is no rise when the mixture is pulled back to cutoff, the idle mixture is too lean. If there is a rise of more than 50 rpm, it is too rich. 

There have been instances where the idle mixture screw has vibrated loose and fallen out. If this happens, the engine won’t idle at all, but will try to shut down when the throttle is reduced to idle settings.


Basic maintenance and troubleshooting

Aircraft carburetors are generally reliable and seldom require much attention. The internal parts of a carburetor rarely need maintenance if the airplane is flown regularly and clean gas is used. 

An inlet screen that the fuel supply line attaches to can be removed for cleaning. Generally it stays pretty clean, because most debris gets caught in the aircraft fuel strainer before it has a chance to enter the carburetor. 

Over time, the throttle shaft bushings wear, especially on training aircraft that endure several power changes and throttle movements every hour. Worn bushings can allow a slight intake leak and cause an overly lean mixture. 

Most carburetors have an accelerator pump that squirts a stream of extra fuel into the intake air as the throttle is advanced so the sudden burst of extra intake air doesn’t create a lean condition and cause the engine to stumble, especially if the throttle is opened suddenly. The accelerator pump has a plunger that gets worn with use and periodically requires replacement.

Any leaks coming from a carburetor are cause for concern. A carburetor that leaks when sitting with the engine off most likely just has a tiny bit of debris trapped between the float valve and seat. Draining the fuel from the carburetor bowl and then flushing it by allowing it to refill and draining it again will most likely clear it up. 

 


Long-term storage of an aircraft

A carburetor on a plane that has sat with the aircraft fuel shut off may not allow fuel to enter the bowl when the fuel is turned on due to a stuck float valve. Gently tapping the side of the bowl with a small rubber mallet sometimes jars it loose and allows fuel to re-enter the bowl. 

If a stuck valve is suspected, momentarily crack open the supply line with the fuel turned on to be sure gas is getting to the carburetor, then re-tighten. Next, slowly remove the drain plug to see if there is fuel in the bowl. An empty bowl indicates a stuck valve or an obstruction in the inlet.

For folks that have an auto gas STC, it is best to never leave a plane with auto fuel sitting in the tanks, lines or carburetor for extended periods. Auto fuel causes deposits of varnish to form on the inner surfaces of the fuel system and often seizes the mixture control valve in place. 

If a plane is left sitting for a season, it will be far better for it to sit with Avgas in it. (Better yet, you may wish to “pickle” the aircraft. For more information, take a look at Steve Ells’ 2015 article “Flying, Interrupted: Modern Engine Preservation” in the archives at PiperFlyer.org.) 

Aviation carburetors are some of the most reliable inventions ever made. Their simple design and quality construction offer years of trouble-free service as long as they are flown regularly and proper steps are taken to ensure a clean fuel supply.

Know your FAR/AIM and check with your mechanic before starting any work. Always get instruction from an A&P prior to attempting any aircraft maintenance tasks.

Jacqueline Shipe grew up in an aviation home; her dad was a flight instructor. She soloed at age 16 and went on to get her CFII and ATP certificate. Shipe also attended Kentucky Tech and obtained an airframe and powerplant license. She has worked as a mechanic for the airlines and on a variety of General Aviation planes. She’s also logged over 5,000 hours of flight instruction time. Send question or comments to .

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Avstar Fuel Systems Inc.
 
Marvel-Schebler Aircraft Carburetors, LLC
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