Joe Lisanke’s Bearhawk Completes the DAR Inspection

Source: 2016 Q1 Beartracks, Joe Lisanke
The project began in 2000 with plans, form block, and some ribs purchased from another builder. It’s a standard build with a few finish items and fairings added for fun and education. The wings were built from plans with the assistance of my neighbor Buzz, who is also a pilot. The fuselage and controls were provided by Avipro (now Bearhawk Aircraft). They did a wonderful job on those parts. The fuselage is very straight and the welds strong. I was very pleased with all the components purchased from them.
The cast door and window handles are still available from B&B Aircraft Supplies. The fairings are all made from laying up fiberglass over a structure of cardboard, plaster cloth, modeling clay, and masking tape. They are one time only use molds, simple and cheap to make. I found some cast metal inside door handles at a fly-in parts vendor that have a VW logo on them. They may have originally been for any early model bug. Those were attached to the front and baggage door frames and pull the release pin when operated.
The panel is a mixture of steam gauges and MGL Extreme 3-1/8” small units that back each other up. The K type thermocouple color coding is counter intuitive: red=negative, yellow=positive. The radios are older King nav coms. Those can still be found online at attractive prices from people who are upgrading their panels to newer Garmin types. You even see some parts radios for sale as low as $100-$200. One circuit board or display could cost over $1000 from an avionics repair facility.
I adapted an ’86 vintage GM DIS ignition unit from the junk yard in place of one of the mags. The older units come in 4 and 6 cylinder configurations, and the only difference is the number of coils, 2 or 3. (http://www.megamanual.com/ms2/GM_DIS.htm). Units self-time for basic timing by receiving pulses from a trigger wheel and pickup coil, 60 degree spacing, with an additional notch at 10 degrees ATDC#1. From that, the electronics knows TDC #1 cylinder and fires coils in the firing order. Waste spark fires two plugs at a time, but the cylinder under compression consumes the most power. Megasquirt (http://megasquirt.info) has documents and finished timing units for those interested in full timing advance curve and EFI. The units are fully programmable. The factory GM ECM and additional sensors could also be incorporated into a design, but that tends to get rather complex to build and maintain. I plan to replace the other mag with the new E-Mag 6 cylinder unit that’s coming out soon.
I used Stewart Systems process for covering and am overall pleased with it. The fabric glue is amazingly strong and allows a glued seam anywhere. The two big issues were with osmotic blistering and delamination of primer coats, both of which were caused by surface contamination. The system demands very clean working conditions and scrupulous cleaning between coats. I used Polyfiber on a previous plane and it was much more forgiving of both of these issues. If you are working in a dusty, drafty area like my hangar, then Stewart probably isn’t the best choice. Plusses for Stewart: fabric attachment, glue products, tapes and supplies. Plusses for Polyfiber: paint layers chemically bond together easily.
Thanks to Ray Howell, the DAR who did the application and inspection. He is wonderful to work with, and a terrific inspector with 28 years of experimental and LSA experience. Thanks to Bob for such a great design!

Engine Storage Procedure

Source: 1995 Beartracks, Bob Barrows
Some of you may already be shopping for an engine for your BEARHAWK. If you are planning to use a Lycoming engine that has just been pulled from another airplane you need to find out the last time the engine was run. If the engine has been in storage for over a year AFTER BEING RUN you will need to pull the cylinders on one side and lube up the cam. In our area we have noted 5 cams going bad after 50-200 hours after being returned to service. If you have a new engine or a fresh rebuild you do not need to worry about the cam since these engines have special lubricant on the cam and lifters. If you are planning on a bolt-on used engine and you are not sure how long it has sat – go ahead and pull the cylinders on one side and use some assembly lube on the cam lobes and lifters.

You also want to be sure that you know the locations of all the oil filter screens on your engine, several models have 2 screens so you should check them both at each oil change. Be very alert to excessive metal found in the screens.

A little preventative maintenance now could save BIG TIME later!

Small Continental Engine Cooling, Center Hole

Source: 2015 Q3 Beartracks
Bearhawk LSA Builder Jerry Cornwell brings up an interesting question about Continental engine cooling. Some Bearhawk LSA operators have found that the engines run warm. He points out that most of the old airplanes designed around the A65 have an extra air inlet in the middle of the cowl, to direct air along the bottom of the engine and onto the oil tank. A quick survey of my Continental-powered hangar neighbors reveals the following “faces”. Jerry does seem to have a point. Perhaps LSA builders could consider something similar. Bob says he’s not done so on the prototype because he’s concerned about the additional drag.

Cowl Air Pressure Testing

Source: 2015 Q3 Beartracks, Jared Yates
Readers may recall Bob Triplett’s reference to measuring air pressure differential under the cowl by connecting tubes to a mechanical airspeed indicator. There is a great article on this topic by Jimmy Tubbs from ECI. This article is so useful because it brings quantitative measurement to a topic that is often relegated to intuition and guessing. Bob spoke about wanting to test his pressure differential to narrow down the cause of a high CHT. In my case, I’m interested in diagnosing a high oil temperature. Bob Barrows suggested that I measure the pressure differential on the front and back of the oil cooler, to see if it is getting adequate airflow. I already have reason to believe that it is getting good oil flow.
The concept is that for air to flow, there must be a pressure differential. For example, Lycoming has provided that a top/bottom pressure differential of 6.5 inches of water should be considered a minimum to adequately cool the O-360 in cruise. What does water have to do with any of this? It’s just a measure of pressure. A certain volume of water will have a certain weight, and when water settled in the bottom of a U-shaped loop of tubing is subjected to air pressure, it will move up or down. Our altimeter settings are delivered in “inches of mercury,” but any liquid can be used to measure air pressure. We aren’t talking about cubic inches of liquid; we can cancel out the width and diameter dimensions, because they are the same on both ends of the loop. The more dense the liquid, the smaller the movement of the liquid, and thus instrument– so that’s one reason why mercury has been a popular choice for barometers.
When it comes to measuring pressure in a bouncing airplane, mercury is sub-optimal for several reasons, so maybe that’s why Lycoming provides the number in the more convenient “inches of water” unit. Airspeed indicators are similar to barometers, except that instead of measuring pressure relative to a standard (that’s what an altimeter does), they measure pressure relative to two sources. Usually those two sources are pitot and static, but it will gladly measure whatever one connects to it. This means that an airspeed indicator can also measure pressure differentials in the cowl. Folks who have been building airplanes for a while probably have airspeed indicators sitting around, but I didn’t. I posted a question to the Matronics Aeroelectric list to see if anyone had a suggestion for a device that could measure low air pressure, and I learned that I could actually solve this problem on my own, by building a manometer. Contrary to the name, this isn’t a device that measures machismo- that’s a stud finder. Rather, it’s just the name for an instrument that uses a column of liquid to measure pressure.
To make the manometer, I purchased a 20 foot roll of clear vinyl tubing from the hardware store, with a 3/8 OD and 1/4 ID. I used some very thin scrap aluminum tubing to create some piccolo tubes. This tubing is available at hobby shops, and occasionally at big box home stores, but leftover brake lines might work well too. This task only requires two piccolo tubes, but I had plenty of stock and got a little carried away making extras. I smashed one end in a vice, and drilled several unorganized 1/16” holes. The goal is to create a static air source at the desired measurement site, and the piccolo tubes help negate possible errors created by moving air over the end of just a plain, squarely cut tube end. This is related to why we put static ports on both sides of the fuselage.
I sourced a piece of non-PMA cardboard (homebuilding has its advantages) and marked graduations in 1/2” increments, with small 1/4” lines. In retrospect, it would have been better if I had numbered the whole inches instead of the halves, but it still worked fine. I used small wire ties to attach a loop of the tubing to the cardboard, and added some small aluminum splicing tubes at the top. In theory, one could run a single tube all the way from the top of the engine, into the cabin, around the loop, and back out to the underside of the engine. I didn’t want to do it this way because it would complicate adding water, and because I wanted to test several differentials on a single flight. This required running a four labeled lines back to the cockpit, which I could connect to the manometer one pair at a time. To get the lines through the firewall, I disconnected the duct from the heat muff to the cabin heat box, opened the cabin heat valve, and ran the lines through there.
I did the flight testing by myself, but it would also work to have someone else to help with the readings. As always, the first priority is to maintain control of the airplane, and not get distracted with science experiments.
Between the top of the engine and the bottom, I found a difference of 4” in climb, and 7” in cruise. On the ground with 1700 RPM, the difference was 3/4”, and in flight at idle and 70 knots the difference was 2”. These meas-urements and my CHT indications agree that I have plenty of airflow for cylinder cooling.
I disconnected those lines and connected lines from the front and back of the oil cooler. In climb, cruise, and descent I read 4, 6, and 3.5 inches. To put those numbers into more familiar units, 5 inches of water equates to 98 knots on an airspeed indicator, or .18 psi. These are very low pressures.
Next I measured the difference between the top of the engine and the front face of the oil cooler. This would show how much of a loss I had just in getting the air from the high pressure area to the cooler. In climb, cruise, and descent, this showed a steady 2” in all phases. In climb, that’s half of my pressure differential, and 1/3 in cruise. Next quarter I’ll have de-tails on the corrective action. Until then, I’ve included a photo of the old installation in case you’d like to make any guesses. This method would be great for sizing cowl inlets and outlets, and deciding if remedies like cowl flaps or louvers are required for a particular installation.

Bob Triplett’s 4-Place Bearhawk

Source: 2015 Q3 Beartracks, Jared Yates
Oshkosh can be a busy and hectic time, usually with too many exciting things to see and do. This year, I had time for a leisurely discussion in with Bearhawk builder Bob Triplett, as we sat comfortably in the shade under his recently-completed kit-built Bearhawk 4-Place. Bob comes to the airplane building hobby with plenty of experience, with airplanes specifically, and fabrication more generally.
He has been a machine shop teacher since 1977, and has worked as a tool maker and machinist for many of those years. This meant building custom manufacturing machines, and in one case, he made part of the extrusion die used to make Lucky Charms cereal. These days Bob is “supposed to be retired,” but he spends lots of time working in a high-end antique auto repair shop. He showed me some photos of a recent timing chain for a 1924 Voisin that he built link-by-link, modifying an existing chain to accommodate a non-standard width. Bob is a maker of things.
The Bearhawk is his “fifth or sixth” airplane, and it follows a Tailwind, an intensive Cub restoration, a Cessna 170, 172, and 195. The 195 was a literal basket case, which he acquired as several baskets of parts. He enjoyed the wide and spacious cabin, but in 350 hours of operation he replaced multiple cylinders, and always had oil leaks. This was part of why he chose the Bearhawk. The slightly smaller Bearhawk cabin is still plenty large for his cur-rent needs, and he says that both are able to handle the same amount of wind. The operating costs are obviously much lower on the Bearhawk.
The empty weight of N94RT is 1395, which includes auxiliary fuel tanks, autopilot servos, 8.50 tires, a 10-inch tailwheel, and a well-apportioned interior. Bob started with a Scott 3200 tailwheel, but upon investigating the source of a noise it made during operation, he found that a piece of it had cracked. He made a Barrows-designed tailwheel to replace the Scott, and has appreciated the slightly flatter ground attitude. I asked if the axle had nuts on both sides to facilitate attaching a towbar. Bob machined his own axle by cutting threads on both ends. “I could have used a bolt,” Bob said, “but then I’d have to buy a bolt.” Bob adds a recent update: “I recently made some changes to the wheel by making new bolt to bearing bushings that extend all the way through the wheel with a sleeve on either side to hold the wheel in the center of the fork and changes out the elastic nuts for castle nuts and cotter keys. This will be a better long term solution. I installed this wheel 30 minutes before leaving for Oshkosh. There may be two additional changes that I may make to the wheel before I get totally finished with it.

Bob’s fiberglass landing gear fairing, and fancy interior

Left: Mark Johnson studies the engine installation. Center: Bob Barrows prefers more frequent fastener spacing on wing inspection panels, similar to rivet spacing. Right: The cabin heat is fed from two muffs into a custom-made Y manifold. It gets cold in Wisconsin!

The engine is a parallel-valve Lycoming 360 that Bob removed from a Pitts. He replaced the cam, which required replacing the cam gears, and replaced the oil pump gears and installed new ECI cylinders. The prop is an 80” MT (MTV15B210). At 2400 RPM and 23.5” MAP, he sees 10.5 GPH and 115 knots, with CHTs in the low 400s. He’d like to see lower CHTs, and has tried installing a plenum above the cylinders. His next step is to try measuring the pressure in the cowl to see if the airflow should be adequate for cooling. Oil temperatures started out high, but he’s switched to a high-density 8-row oil cooler, and after that he’s seen temperatures less than 190 degrees F.
The paint job turned out very nice, with Polytone on the fabric and Aerothane on everything else. The interior is very classy, with lots of specially-made touches. Parking next to his airplane would make mine seem pretty ratty.
Bob used the new Additional Pilot provisions of AC90-116 for his initial flight testing. Bob’s Qualified Pilot (QP) handled the stick and rudder tasks while Bob monitored engine parameters and the overall situation. The QP had thousands of hours of experience in general, but no experience in the exact model. Like many other first-time Bearhawk pilots, he was surprised by how soon the airplane lifted off in the takeoff roll. The two completed a pre-designed test plan in about an hour of flight time. Later that day they repeated the process. One of the landings was a little bit firm, but the airplane was well-suited to absorb the energy. Of all of the planes he’s owned, Bob prefers the Bearhawk’s landing gear, due to its dampening and forgiving nature.
Bob had a great parking spot on the line at Oshkosh, and he had lots of visitors. It sounds like he is enjoying his Bearhawk, and I certainly enjoyed talking with him about it.

Fixed Pitch Prop and a Lycoming 0-540

Source: 2014 Q4 Beartracks, Heath Sneller
There seems to be some interest in running a fixed pitch prop with a Lycoming 0-540 engine so I’ll just share my experiences. This set up isn’t for everyone and I won’t try to convince anyone that this is the best or only way to go, but it has met my build goals and so far has worked out pretty well. After I decided to go with a fixed pitch prop I contacted Craig at Catto Props and told him I wanted to go 120 mph and burn 8 g/hr. They will build it to go fast, slow, or anywhere in between. He did some number crunching and said that a 3 blade 80” diameter prop with a 55 degree pitch should work, and I believe he reached these numbers using a cruise altitude of around 8,000 ft. This sounded good to me so I told him to build it. Catto props use a wood core with a carbon fiber wrap and I elected to have the nickel leading edge put on.
In order to use this prop you have to change out the lugs on the end of the crankshaft that the prop bolts engage or use an aluminum spacer from Saber Mfg. I used a spacer from Saber and I believe it’s around 2 ¼ inches, this way if I ever decide to put a constant speed prop on down the road I won’t have to change my engine cowling. Another thing to consider when ordering a prop from Catto is that you can get a custom fit spinner. The spinners that they use are from Vans and they drill the holes for the screws and make the cut outs for the prop blades. I ordered one with my prop and had to do just a little sanding in the blade cut outs to make it fit (about 15 minutes of work), so to me it was worth ordering.
So how does it perform? That depends on your mission. If it’s just me in the airplane and a slight headwind I can be off the ground in less than 100 ft (temp makes big difference), with a 1,000lbs of people and fuel and a temp of 90 degrees it takes around 1,000ft. This works for the type of flying I do, I am not going to take my family into a one way bush strip but if I want to play around by myself or with a small load in the airplane I can get into and out of just about anywhere.
So how does it cruise? During my testing phase at 3,500ft msl and 2050rpm it gave me TAS of 100mph and burned 7.5 gph. On a recent hunting trip I flew at 5,500 and 6,500ft msl turning 2250rpm and burned 7.8gph with a TAS around 110-115mph. So far in the first year of flying it I have put on 90 hours and 70% of that has been just local flying at 1,000ft agl burning just over 7 gph at 2000 rpm. I really don’t care to go fast or high, the only time I get above 1,000agl is to get a smooth ride with passengers on board. If I flew at 8,500ft I could probably get close to a TAS of 120mph and a fuel burn of around 8 gph, but I like to stay close to the ground and look at stuff. The things on my airplane that probably rob it of speed are 8.50×6 tires, round tubing for shock struts, and that my gear legs are not streamlined.
Overall with this set up it is very close in speeds and fuel burns to the Cessna 172 I use to have, it just uses a lot less runway and can haul a lot more weight. If I want to go fast it will but it’ll just burn a lot more gas. With a constant speed prop I know I could go faster and get off shorter when fully loaded but for now it works and meets my mission.

Bob Triplett First Flight

Source: 2014 Q3 Beartracks

Congratulations to Bob Triplett on a successful first flight for his new Bearhawk 4-Place! The engine is an O-360 A1D and the prop is an MT-15-B. The empty weight came to 1396 and the first flight was out of Rice Lake Wisconsin, RPD. Bob says “It gets of the ground very fast. We flew 1.1 today. The rigging is almost perfect as we can fly hands off for a good period. Reluctant to let go too much as it is a new plane and something could go wrong any time. We have some new airplane problems. High oil temp issues with high cylinder head temps. It seems to be coming down and is to be expected with a new engine. We will see how the engine breaks in. The trim system seems to perform well. Not as sensitive as some. Did an approach stall with no tendency to drop a wing tip. It tracks very straight down the runway. Very happy with the ground handling. It is on 850 tires so the visibility could be better but that is the price for the larger tires. This might end up being a keeper for some time.” See Beartracks 2012Q4 for more details and photos of Bob’s project!

New Hot-Rod Bearhawk Patrol in Virginia

Source: 2014 Beartracks, Jared Yates
Hatcher Ferguson and Don Aldridge have just completed their second Bearhawk Patrol, and it is a showcase of experience and ingenuity. The two built N22HD with performance in mind, and spared almost no expense. The fuselage is welded from a VR3 tubing kit, and the quick-build wings are from Bearhawk Aircraft. The engine started out as an ECI IO360, and now it flies as a fire-breathing 210HP example of “the best they could make it.”
Sky Dynamics of Moneta, Virginia modified the engine with a light-weight cold-air sump and induction system, lightweight flywheel, and 4-into-1 exhaust system. After the modifications Sky Dynamics ran the engine on their dyno to validate the performance gains. Two P-mags drive the electronic ignition system, and the fuel injection servo is from Don Rivera at Airflow Performance. Hatcher and Don Aldridge initially purchased a used Silverhawk fuel injection system on eBay, but the engine ran terribly with it. They took the servo down to Airflow Performance and found that it had been contaminated with water. Airflow Performance swapped out their servo for another, and now it runs beautifully. All of that power is turning an 80- inch carbon fiber Whirlwind prop, and Hatcher reports takeoff rolls consistently under 100 feet. Why did they install such a high performance engine? When I asked, the answer was along the lines of “to see if they could.”
Hatcher and Don know that the best way to further boost performance in an airplane with this type of hot-rod engine is to reduce weight. They considered weight savings in nearly every construction decision that they made. For example, they eliminated the skylight, rear seat throttle control and brakes, and the baggage door. They installed light-weight single puck brakes, used micro nutplates throughout, substituted #6 screws for #8 screws whenever possible, and minimized the size of welded tabs. The lightweight tailwheel assembly is Bob’s design, built by Eric at BHTailwheels.com. They redesigned the seats to reduce the width of the rear and increase the width of the front, and had a hot-rod shop shape the foam and sew the leather upholstery. The miniature Becker radio and transponder save a few pounds, as does the vacuum-pad alternator. The lithium battery saves approximately 15 pounds over a comparable Odyssey, but it still turns the engine over with plenty of gusto.
In some cases they added a little bit of weight to make the airplane more safe and functional. The LED lights and strobes give better inflight visibility to other airplanes, and allow for flights later into the evening when the flying is good. Hatcher says “they’re all LEDs, which hardly weigh or draw anything.” When that engine is running at full power and burning 17-18 gallons per hour, cooling is a concern. A cowl flap adds a little bit of weight but keeps temperatures normal. In the end, this airplane’s empty weight is 1168 pounds, 30 pounds lighter than their last.
A local expert helped fabricate a two-piece all fiberglass cowling. This doesn’t save any weight, but the new cowl is much easier to install and remove, and it has a more complex shape that reduces drag. The installed cowl is the third one made from the female mold. The first was two heavy, and they reduced the thickness of each of the next two. Hatcher speculates that they could save a few pounds by using carbon fiber instead of fiberglass, and fortunately they can use the same mold with carbon fiber to test that theory in the future.
What’s not to love about such an advanced flying machine? The paint, according to Don and Hatcher. Everything was going well as they applied the Polyfiber covering system to the powder-coated airframe. After they started painting top coats with the same Imron paint that they used on their blue Patrol, DuPont discontinued the product and they had to switch to the new “XL Pro.” The new product didn’t match the old product to their satisfaction, so they had to repaint several parts, at an estimated expense of 10-15 pounds. Hatcher says that he’s not satisfied with the way the paint turned out, but I’ve yet to meet an amateur airplane painter who will tell you he is. If the two fly it to Oshkosh next month as planned, I suspect that they won’t receive any complaints about it, especially if it is parked anywhere near mine!
The big question is, how does it fly? The specifics are still pending as they refine the calibration of their instruments. Hatcher reports that it handles just like their last Patrol, but has a much shorter takeoff, steeper climb, and faster cruise. They have only taken it on a few short trips, so they don’t have good cruise performance data yet. Hatcher says for local flights he uses about 13” MAP, 2300 RPM, and gets 100-110 miles per hour at 5.9 gallons per hour. If he runs the engine hard in level flight, his cruise speed begins to approach the realm of VNE, which is the main reason that their Patrol is a little bit slower than their RV10. Bob Barrows has flown the airplane and says that he likes the way it performs. Like most experimental airplanes, this new Patrol still has a few tweaks in the works. The static RPM is only around 2600, and Hatcher would like to gradually adjust it up to 2700. He would also like to fit a set of his giant wheel pants (for 6-8.50 tires) and build some fairings for the shock struts. I asked if they had kept track of how much they had spent on the project, and Don said “Yes, but we don’t discuss that!” with a laugh. Both are quite pleased with the way the airplane turned out, and I’m looking forward to seeing it in person!

LSA Builder Update from Rolly Clark

Source: 2014 Q1 Beartracks, Rolly Clark
Mr. Barrows flew down to 52A back in October to make up an engine mount for production at AviPro’s factory. He would be using my fuselage as a jig. I was very eager to see Barrows in person and look his LSA prototype over. I could hear him coming for about 3 minutes before I could see him. I was curious as to what he would bring with him. He brought an O-200 case, three sticks of 4130 tubing about 30 inches long (guessing), four steel disks about an inch in diameter, and some aluminum disks to simulate the Lord mounts. He also brought an electric grinder and a hack saw! I had tried to set my fuselage up according to the LSA Book, with everything plumbed and square and the string that represents the thrust line pulled from the tail to the spot where the engine case would set. After greeting, he went to work setting up my fuselage for the job. He said, “you’ve the right idea but we need to change a few things.”

He then took measurements from plumb bobs (he let me help) and made marks on the floor of my hangar, and generally got things organized. He admired the C-170 that was also in my hangar and told me how he used to fly one picking up and delivering engines to customers. After an uncomfortable experience with it, he decided he need an airplane that was better suited to his purpose. I took that to mean it had more power and room and easier to load and un-load. The result of course was the 4-place Bearhawk.
It was interesting to watch him work – not much wasted motion. He said a fellow named William Wynne would be driving up from Florida to help and this fellow was a Corvair aero engine expert. Well, that really got my interest up as there is a very active EAA group in Carrolton, Georgia, where they have built a bunch of Peitenpols and put Corvair engines in them. I had flown over there about a year ago. I watched them fly and looked them over carefully. That Corvair engine is very impressive and it does a good job in the Piets! Incidentally, these Pietenpols were modified a little and were called “Big Petes”. The main change was to make the small cockpits big enough for the big Georgia boys to fit. About the time Mr. Barrows got everything all set and ready, Mr. Wynne drove up pulling a covered trailer that housed his Air Corvair equipment.

After greeting all around, he pulled out a ramp and unloaded what he needed. It consisted of his MIG welding rig (gasp!) and his Corvair case, and his Corvair complete engine. Six cylinders and 110 HP!
What a beauty! Those gentlemen worked that afternoon and the next day and had two prototype engine mounts for production purposes to show for their work. I tried to stay out of the way while watching what they were doing. I would also go out to the LSA, which was tied down on the ramp, and look at what I thought I might find interesting. When all the welding, etc., was finished, Mr. Barrows offered me a ride. I am a very experienced pilot and it does not take me long to evaluate an airplane. It is a good flying airplane with good control harmony.
Control response is just right all the way down to the bottom of the envelope. It slips well, which is good if you are high on final. Mr. Barrows airplane is very basic with only the minimum required instruments – no electrics, no nothing. When I was getting in the plane, he handed me some earplugs! They were needed! The airplane is loud. There are no mufflers and exhaust pipes are right under your feet.
I plan on mufflers, and an electrical system on my plane. I am next to the ATL Class B and feel the need. Mr. Wynne went next and I watched the take-off. Not much runway needed! Rapid climb. Looked good. When they got back, I helped them load their equipment. Mr. Barrows asked me to give him a prop, which I did and then off he went back to Virginia. Mr. Wynne and I visited some more while he was finishing preparing to leave. He gave me some interesting advice about electrical needs on my airplane.
I hope to get this airplane done and in the air in the next several years, but in the meantime I look forward to the learning experience of building this unique airplane.

Engine Preheater

Source: 2013 Q4 Beartracks, Russ Erb
This past winter here in Southern California there were several mornings when I wanted to go fly that the air temperature had dropped below freezing, and I was concerned about causing extra wear on the engine from starting it with cold oil. Additionally, I would have to burn extra fuel while idling, waiting for the oil to warm up. I found out that a friend has an oil pan heater on his Cessna 180 that he will plug in the night before for situations like this. I asked him how he made the decision to install an oil pan heater, and he replied it was there when he bought the airplane. After all, it was previously based in Maryland.
Even so, he agreed that it adds less than one pound to the airplane (in my case that moves the cg in a favorable direction anyway) and if it made me feel better, then it was probably worthwhile. It was only $150, which in airplane terms is quite inexpensive.
The heating pad is a peel-and-stick to the bottom of the oil pan, but it requires removing the paint from the oil pan first, and applying pressure to the pad for an extended period of time after installation. This last part was a challenge, since it was too long to hold it in place by hand, and there was a bunch of other stuff in the way. My solution was to take a 2×6 and cut it to match the shape of the pad (which was not flat), and to cut reliefs around the other obstructions. This block was then held in place with a broomstick cut to length. The fuel line fitting into the carburetor conveniently held the broomstick in place.
Pressure was applied to the broomstick using a small floor jack. Care was used to not apply too much force, stopping when the broomstick started to buckle. To keep the jack from rolling out of position it was placed on a 2×4 so that the wheels were off the floor. The 2×4 appears white because it was wrapped with paper from a previous use.
The heating pad has a thermostat so that it won’t exceed a set temperature. This means you can leave it on overnight without overheating the oil. However, you don’t want to leave it plugged in all of the time, because the warm oil will tend to evaporate the dissolved water, increasing the risk of internal rust and corrosion. Not so bad overnight, but could be bad after many days of being plugged in.

Bearhawk.tips

Tips for building your Bearhawk airplane