The Aircraft We All Wish We Could Buy New
When a person begins the search for the model of aircraft that will best fit your most common mission profile, you attempt to define and prioritize wants and needs that will fit into your defined budget. Compromises are evaluated between things like: 2-place or 4-place, speed, cargo capacity, VFR or IFR? Will it be used on unimproved strips or paved runways? Then the costs to acquire operate, maintain and insure come into play.
The Light Sport category of new aircraft brings several possibilities into play. But most are only small two place aircraft and still run well in excess of $100,000. One can look into new Normal Standard category aircraft, but quickly discover that it requires an even larger amount of investment.
The end product: A 170B that is basically better than new.
This dream project began with the question: "Can a Cessna 170 be made a bit faster and have a modern panel?" Answer: "YES it can!" There are over a hundred STCs that apply to the C170 that allow one to customize it to your exact mission profile. I wanted a 4-place plane with large cargo area. My wife loved the visibility of the 170 because of the low panel and high wings. The doors are large and removable. The seats are also removable for bulky cargo and the load capacity and short field performance is spectacular. And the 170 is a very rugged plane that can handle rough use.
The Candidate
Kris is a good friend of mine I have known since childhood. He has a wonderful habit of buying planes and old cars and rebuilding them. He is a masterful technician who is as comfortable with a rivet gun and sheet metal break as most of us are with a TV remote. His impeccable work quality is recognized by the local FSDO and he has successfully adapted many modern features into old planes by way of field approvals.
The stripped-down and primered fuselage of our candidate
Kris recovered this plane from near abandonment off a ramp at a rural Pennsylvania airport were it sat unused for many years. Brought back to the Midwest with the intention of parting it out, it was discovered this plane was "ugly as sin" on the outside, bit was "pure and clean as an angel" inside. As a result, Kris decided to keep it as his next project. He began by removing the skins from all the wings and control surfaces to facilitate cleaning, inspection and zinc chromating. The floors and firewall was removed so the entire fuselage could receive the same treatment.
The Build Plan
The plane is a 1955 Cessna 170B. The "B" model was preferred because of the best wing design of the three 170 models. It has the largest ailerons and big Fowler style flaps that are adjusted quickly and easily with a convenient single lever between the seats. The "B" also re-routes control cables to the subfloor, making a clean useful load area. And because it was certified under Civil Air Regulations (CAR) Part 3, it is much easier to get modifications done and approved (more on the changes to the cabin, wings below).
The panel structure stripped to its core and primered, with repainted T-yoke, new U-joints, and a fresh new firewall added.
The Engine
The stock engine in a 170B is a 6-cylinder, Continental 300 cubic inch with 145 HP. There are several STCs that provide for the upgrade of the engine to the 4-cylinder Lycoming -360 series that makes between 180 and 210 horsepower. There is negligible weight difference between the O-300 and O-360, and the extra power is a real bonus! We chose the Del-Aire engine STC. We bought a Lycoming O-360-A2D with only 65 TTSN, and replaced the 'shower of spark' mags with new Bendix dual impulse coupling mags. This allows for hand starts even with zero battery voltage. The starter motor and alternator were changed to lightweight B&C models and an MT compact propeller governor installed to save weight. A spin on oil filter adapter was also added along with the Bracket air filter. The intake and exhaust ports were polished to aid in airflow. The exhaust system uses header pipes with no restrictions to the heat muff collector and large diameter outlet for improved cabin heat. The engine was dressed up by adding a bit of "bling." The paint used is Lycoming Grey with a bit of hardener added for shine. The baffles were painted black before installation. Push rod tubes, rocker covers and intake risers were chrome plated. Copper lines and brass fittings all received a good polish before installation.
A shiny new blinged-out Lycoming O-360.
A shiny new blinged-out Lycoming O-360.
Propeller
A 79" MT Composite 3-blade constant speed propeller from Flight Resource was selected to harness the engine HP and turn it into thrust. The MT prop is lighter than the fixed pitch prop and allows the owner to use the full power of the engine at takeoff and set for low rpm for economy cruise. The composite blades tame and absorb the notoriously strong firing pulses of the -360 series engine and the prop has stainless steel leading edges for unlimited life and durability. It provides the highest static thrust of any prop available for this engine.
Wings
A Sportsman STOL kit was added to the wings. It elongates and droops the leading edges of the wings a bit. This results in a lower stall speed and improved low speed handling without the penalty in cruise speed. Gap seals are then added to both the flaps and ailerons to further control airflow and reduce drag. The wingtips are changed to a molded Horton style that also aids lift by controlling air moving out and away from the wing. The wings, flaps, ailerons and tail section interiors were all washed and painted with zinc chromate before installation.
Wings freshly painted with base coast and wearing a Sportsman STOL kit.
Landing Gear, Wheels and Brakes
The stock gear Cessna installed on the 1955 C170B is nearly perfect. It is a bit stiffer than earlier years and has a nice looking shape. A P-Ponk gear box reinforcement kit was installed as well. The plane will be equipped with Federal AWB Hydraulic Wheel Skis, so the stub axles and brackets were fitted at this time. New Cleveland wheels with dual cylinder brakes were installed that allow for the use of tires up to 32" to be stopped with ease. Of course, all brake lines are new and the master brake cylinders were rebuilt as well. It will be fitted with 8.00 tires to begin with.
Late model "lady leg" 170 gear + PPonk beef-up kit were used, with the occasional addition of Federal AWB wheel-skis.
Fuselage
The goal is to make this a strong, light weight 4-place plane that can carry over 1000 pounds of fuel, cargo and passengers with ease and comfort. With the advent of active noise canceling headsets, the need for heavy sound insulation is eliminated. The entire interior of this plane was stripped, zinc chromated and painted. No interior trim panels will be used.
A spartan, very functional interior was used.
The seats were stripped of the old, heavy springs and wool padding and replaced with Ceconite bases covered with modern aircraft padding and fabrics by Sport Aircraft Seats of Wasilla, AK. New seat rails and inertia seat belt systems from BAS are used too.
Skylights were installed as done in the Cessna 120 and 140 models. A baggage door from a Cessna 172 was installed along with the Extended Baggage STC by Selkirk.
What 170 pilot hasn't done the balancing act when checking their fuel? The addition of the grab handle is a nice one.
New control cables, bearings and pulleys were installed throughout. A BAS retractable tail pull handle will make it easy to move around. Because the plane will be operated on skis and the possibility of floats, a float kit from a Cessna 180 was used. This kit uses larger reinforcing doublers spreading any stress over a larger area. A V-Brace by F.Atlee Dodge will strengthen the forward cabin door frame areas.
New fuel lines were bent and installed with new AN fittings. Cowl steps and grab handles on each side will make it easy to get up to the fuel tanks or windshield without a ladder. All the windows were replaced with new. The hand pump and hydraulic lines for the skis installs between the seats.
Fancy new entry steps were added.
Instrument panel
A new panel was cut and only the basic instruments required by the type certificate will be reinstalled. The engine STC adds the need for manifold pressure and fuel pressure gauges. A Garmin 496 in a AirGizmoz mount provides GPS navigation. A Electronic Flight Instrument System from Grand Rapids Technologies provides the means to monitor every aspect of the engine operation, fuel burn and power being produced. The EFIS display also takes GPS data from the Garmin along with pitot and static air data and feeds from a remote magnetometer and built in AHRS to provide a full function backup guidance and flight direction system. It even includes AOA functionality.
Wiring
All original wiring was removed and will be replaced with modern Teflon coated wires. Fuses are replaced Klixon breaker-switches. Whelen tip strobes were installed to help to be seen. Interior panel lighting is a combination of dim-able self-lit, post lamps and a LED light strip under the eyebrow of the panel.
Radios
A new 720 channel digital radio and King Mode C transponder is in place for now. ADS-B will be accomplished later by swapping the current transponder . An external GPS antenna was mounted at this time. A PS Engineering 4-place stereo intercom with multiple aux (music) inputs makes communication and entertainment in the cabin perfect. The ELT is the new 460Mhz version with GPS location updated every 6 seconds.
Paint
The exterior is finished with a full coat of Imron White, then a bit of contrasting color will be added. The entire interior is painted with a light grey US military enamel. These paints cover with one coat and are both extremely durable and easy to clean.
Reassembly Begins
All the big parts had now received the cleaning, primer, and paint routine. The engine was mounted to the airframe and the tail was reinstalled along with the gear, brakes and wheels. It was beginning to look like a real plane again!! The radio shop was ready. Once there, work began to install, wire, and test all the radios, avionics and plumbing. This takes much longer than you would expect, so be patient with your shops. I can not tell you how many times this panel was installed and removed during this process!! Each time a part was added, you need to do it again to check fit and function and verify no interference with other parts of the plane.
Then we were able to insulate the cabin side of the firewall and install the new control cables from the engine to the panel. Next up was punching holes in the firewall for the fluid, electrical, tach, primer, pressure and control cables. Yes it is scary; measure three times and hope to cut once! Then route cables, checking again for interference and binding. The same is done for primer, oil, fuel and manifold pressure lines. About this time we fired up the panel while in the plane and performed a pitot static and function checkout of the radio, transponder, encoder, intercom and panel lights. It all worked perfectly!!
Now the avionics shop turns the plane back over to my command to complete the connections for heat controls, governor, carb heat, mixture and throttle. We replaced all the fluid lines firewall forward with new. The gascolator was replaced with a modern aluminum style one. The old wet cell battery was replaced with a gel cell battery and stainless battery box from F. Atlee Dodge. New power and ground cables installed from Bogart. The engine side EGT, CHT, Fuel Pressure, Oil Pressure, Oil Temp sensors that feed data to the Grand Rapids engine/flight data collection system were installed. Care was taken to keep these completely separate from the direct-reading "steam gauges" required of the TCDS.
Now it was time to move the plane again from the avionics shop to my shop were the plane would be based. We padded and wrapped the entire fuselage and loaded it onto a flatbed car hauler and drove it 50 miles to my home field. Here, I would enjoy being only 4 miles from home with heat, good lighting and all my tools at hand to complete the assembly.
The flaps and ailerons were sent out to be re-skinned while the paint shop finished adding the color coats to the cowl and other small parts. The goal was to hold off on mounting the wings until as late as possible because it is easier to move around the plane without them.
Since this plane is equipped with Federal AWB Hydraulic Wheel Skis, we installed new hydraulic lines beneath the floor that terminated next to the brake line exit at the gear leg. The placement is critical to allow the rear seat to be installed and not interfere with the hand pump that mounts just behind the fuel selector/flap tunnel.
Before closing up the rear part of the fuselage, one more check is made to adjust elevator, rudder and trim for proper tension, function and limits. We found the elevator cable run with a twist that required a trip to the most rear of the plane to re-do. A digital camera sure made it easy to spot the trouble and get it correct.
Next the door window frames got cleaned, primed and painted. New plexi is installed and the window hinges are then riveted to the doors. Door and window seals using modern soft rubber makes the cabin draft free and quiet.
We now install the BAS inertial reel harnesses and test fit all the seats to the plane. This is the first time to sit on the actual seats in the cabin with the panel fired up and see it all come to life…what a great feeling!
A must-have for backcountry pilots: inertial reel shoulder harnesses. These are BAS Inc.
The cowling, flaps and ailerons come back from the paint shop. We finish testing and securing sensor wires around the engine, double check and mark with Torque Seal all connections in the engine compartment, then mount the lower cowl...it fits and all the color lines line up!! Same with the top cowl and doors!! Now take it all off and rivet the inspection door hinges and add Teflon tape to prevent chafing of the paint as it contacts the fuselage.
Next is installation of the wings. With 5 or 6 talented, trusted, and patient friends, we moved them into place, test fit, adjusted and repeated until each one fit securely into place with spar attachments lining up and no contact with the new one-piece plexi windshield. We set the rear washout adjust blocks into the center position to begin with. (It turns out that is perfect and no further adjustment was needed upon test flight.)
New stainless steel control cables are now installed with new pulleys. One gets very patient at feeding washers and nuts into blind areas with a magnet and dental picks. There is a good reason the retainer pins (cotter keys) used with the cable/pulley systems are aluminum as opposed to steel...they are often placed in areas were it would not be possible to remove them unless they were "soft" enough to be grabbed and pulled out with long thin picks. Their function is simply to retain the cable, in the event of it becoming slack, within the operational groove of the pulley. Checking cable runs, looking for overlaps or rubbing is easy with modern, small digital cameras. We used an eight foot long section of 1/8" aluminum tubing to guide many of the cables through the wing.
New seat upholstery and a basic, utilitarian backcountry interior.
The aileron bellcranks, cables and pulleys are then installed. Next the ailerons are mounted and everything adjusted until they operate in both directions evenly and to specified up and down angles.
The flap operation bellcranks and cables and pulleys are then installed and set to initial factory settings. The flaps have seen improvements designed by MacFarland to prevent the track/guide wear issue common on these Cessna’s. We installed the latest upgrade kit and installed the flaps, made adjustments and then installed trim fairings.
Next we moved to the left wing and installed the landing/taxi lights, pitot, stall warning and associated wiring into the cabin. It took a lot of time and patience to adjust the interior wing root faring that have the air vents in them because of the change in wing shape with the leading edge cuff installed.
Now with new fuel tank caps, we connect the fuel and vent lines, add some fuel to each tank to check for debris, flow and leaks…yup, we had to redo the top gasket of the fuel selector valve!! The fuel flow sensor requires calibration, so it provided an opportunity to run a lot of fuel through the system. The mechanical fuel level tank gauges were not functioning, so the tanks were drained and new floats and gaskets installed.
The 3-blade MT Composite Prop got mounted along with the final fit of the flywheel and alternator belt. We rented digital calibrated scales and determined new empty weight….it is 1405 pounds. That is only 70 pounds more than the last W&B report done some 30 years ago and with all the original factory engine, instruments and interior.
Now the rest of the paperwork is collected together and reviewed. The changes and new part replacements to this plane required over two dozen 337 forms to document the installations. My A&P (IA) and I did a very thorough inspection and he approved the plane to return to service! It is now only one week before AirVenture 2014 and I wanted to be there to park with the C170 group.
The tanks were then filled with fuel, and following a careful preflight check with notes of key measurements to be monitored, the engine is started for the first time and runs great. The prop is cycled several times to purge air and verify operation while the plane taxis to the end of the runway. Oil temp and CHT is now good for take off. Full power applied and she is off the ground faster than I expected. I continued to run at full power in shallow climb circling the field to about 3000’ agl and began to check and record temps. Oil Pressure and temp came down and became stable after about 50 minutes. I slowly reduced power, landed and we all celebrated with a beer and high fives. The engine went through 3 quarts of oil before consumption stabilized. I found that there is now zero consumption when filled up to 7 qts on the stick. If you go to 8, it will drop to 7 in short time and then stay there…so I will keep it at 7 qts. I run a semi-synthetic with CamGuard added. The first oil and filter sample was tested and came back ‘normal’ in all tests for a new break-in engine.
I took the plane to OshKosh and parked with the C170 type club. Great Fun!! On the way back, I made a precautionary landing in a field when my fuel pressure began to drop into the red. It turned out to be a collection of spider webs and bug debris had clogged the filter in the gascolator. Easy to fix and move on. When I got home, we flushed the tanks, lines and cleaned all filters again. No issue since then.
Performance
I have about 50 hrs of flight time on her now. I took a 5-day trip covering nearly 2,700 miles from Wisconsin to Wyoming, Montana and back. This trip allowed me to spend a lot of time exploring various power and RPM configurations to determine fuel flows and speeds this plane is happy with. The new gauge I love the most is fuel flow and the remaining fuel. It is so comforting to now exactly how much fuel you have at any time and be able to know precisely how much will remain when you land at a given waypoint or destination. Using this feature, I was able to determine best range settings for power and prop.
John having too much fun on his Federal AWB hydraulic wheel skisPhoto: Don Zank
Because this is a carbureted engine, it runs rough at lean of peak settings, so I operate in cruise at 50 degrees rich of peak. It seems at nearly all power, RPM, OAT and altitudes that temp on the hottest cylinder (#3) turns out to be about 1,400 once leaned out and settled in.
The MT propellers love to operate at low RPM. I can not describe in words how cool it is to cruise around at 1,900 RPM and 22" of MAP. It is so quiet and smooth!! For my trip out west, I found happiness at 2,000 RPM, 23" MAP, density altitude 6,000’, fuel burn at 7.8 GPH and TAS at 116 MPH. Bump it up to 24" and 2,300 at 8.7 GPH for 126 MPH TAS. Best speed was at 3,000’ D.A.; 27" MAP; 2100 RPM and 8.9 GPH at 139 MPH TAS.
N170KW enjoying the scenery at Russian Flat in western Montana
The take off and landing ability of this plane is nothing short of being called spectacular!! I operate from a grass strip at 1,000’ MSL. It is easy to get the wheels off the ground in as little as 200’ using those big flaps to jump it in the air, then easing them back off with the nose down until climbing speed is made to clear any obstacles. It flies very slow, with full flaps and power, you can get it to stall just under 40 MPH IAS. Stalls are rather a mush than a break. When you add full weight there is not nearly the change noticed in performance that I had to be aware of with my O-300 on the front. When the lakes freeze up and snow covers the land, we install the skis (takes only 40 minutes) and continue the fun year around! This is a great plane to take ice fishing on remote lakes that one can only get to by plane.
The interior trim has now been completed. We went simple and light weight. I would not have installed the front side kick panels except they have the integrated heat ducts needed to move some heat to the rear of the plane. A custom made cowl blanket to keeps engine preheat in. The control wheels and grab handles received black leather covers.
Summary
Yes, I have invested an enormous amount of money into this plane to make it new. The justification is simple: A new Husky, Scout or Maule will claim $200,000+ of your money. A new Cessna 172 will be way north of that. I wanted a 4-place, aluminum plane with conventional gear, digital panel, floats, hydraulic wheel skis and a useful load of nearly 1,000 pounds that can fly all day long on 8 GPH in and out of short, unimproved strips with visibility nearly unmatched. The fact is, there is no such plane produced today at any price. So, as we began the story, a "better than new" airplane for about half the price of new!
Full photo gallery
https://backcountrypilot.org/features/category/featured-bush-planes/better-than-new-cessna-170b-rebuild/56-better-than-new-cessna-170b-rebuild#sigProGalleriacf7a0fa8dd
