JOESOAP's Guide to Flying the Bell Jetranger
This is intended as a basic guide for the Bell Jetranger. As with other parts of this website, it is a work in progress. Check all information before using for planning purposes.
Ahhh. The reliable old Jetranger. A good helicopter by all accounts. Well, most accounts anyway. As with all aircraft, people have favourites and I am never shy to admit that the Jettie is one of my favourites.
The original Jetranger was designed in the late 1960s as a competitor for the US Army Light Observation Helicopter program. The OH58A was the original version and was also known as the Bell 206A. That's about all I can tell you about the A version.....
The 206B was the next version and is also known as the Jetranger 2. It was powered by a Rolls Royce (formerly Allison) 250-C20 engine producing 400 SHP.
Around 1978, the next version, the 206B3 was produced. It had an upgraded engine, the Rolls Royce (Allison) 250-C20B or C20J engine producing 420 SHP. It also has a larger oil cooler and larger diameter oil pipes, different tail rotor blades, redesigned full tank so as to allow up to usable of 91 USG without need for the optional range extender and one or 2 other improvements.
Around 1983, the doors were upgraded with extra locking pins and better handles. Later options also include the option to fit a 250-C20R engine which produces 450 SHP. In my opinion, the power improvement is not enough to make it worthwhile. The C20R engine can be problematic at times.
Weight and balance
Max weight for the Jetranger is 3200 lbs (3350 with external load). There was a optional STC kit released by Bell a year or 2 ago, which allows for an increase in Max internal weight to 3350 lbs, but unless you operate somewhere cold at sea level, you are unlikely to be able to use the extra payload.
Basic weight for most Jetrangers is around 1850 lbs, so if you have a full load of passengers (1000 lbs including pilot), that allows for 350 lbs of fuel (50 USG) or around 1.5 hours endurance with reserve.
Obviously if you have floats fitted, the basic weight will increase and for a Jetranger with floats, a good ballpark figure is 40 USG of fuel with pan-style floats and 45 USG of fuel with lightweight pop-out floats if you are going to have a full load.
Fore / aft center of gravity limits should be monitored when loading passengers, as especially with low fuel and somebody really heavy in the front, it is possible to push the C of G beyond the forward limit. If this happens, it is possible to run out of aft cyclic control when getting airborne. Not great if there is an obstruction in front of you. There is also a minimum pilot weight limit of 170 lbs and pilots weighing less than this will need balast in front with them to ensure they do not exceed aft C of G limits (especially with full fuel)
Preflight and Start
There are 2 things that most pilots will do or almost do at some stage. The first is to engage the starter without untying the blades. The second is to overtemp on start.
The first can be easily avoided by a good preflight and LEARNING GOOD HABITS. When you preflight, untie the blades and turn them backwards 90 degrees. When you get into the aircraft before start, check the controls and look at both blades for movement. If there is only one in front of you, you will realise that the blades are still tied.
The second is not as easy to avoid. Starting limits are 810'C for 10 seconds and 927'C max. More than either is a hot start, which will illuminate the warning light if fitted and requires inspection.
Unless you have really messed up, damage will not normally be evident, but don't expect the innards of the engine to reach their life limits before having to be replaced.
So how do you avoid a hot start? Well, first off, don't crack the throttle before the N1 reaches 12%. If it doesn't get there, use external power to start. If you do a lot of trips away from base, try to get a portable external power pack to take with you. Secondly, use 2 hands to start. Hold the cyclic with your knees, push the starter button with your right thumb and DON'T LET IT GO till the N1 is 58%. DO NOT RELEASE IT if the temperature starts running away. Check for oil pressure rise and open the throttle postively through the gate with your left hand, then roll it back to the stop and depress the idle cut off button. Keep it depressed so that you can roll the throttle off if necessary without having to fight with it. (This procedure is for a Jetranger with the Bendix FCU. For CECO FCU, the throttle needs to be rolled open slowly till light-off. The vast majority have Bendix system fitted.)
Back to the pre-flight. What should be checked that the flight manual doesn't mention ? Well, I like to check the transfer tubes on the side of the engine to see if they are loose, check for cracks in the engine casing, check the temp strips on the driveshafts, check for excessive oil splatter from the short shaft (not a good sign). Obviously all oil levels are important. Even though tail rotor blade failures are rare on Jetrangers, I always check for cracks near the blade root. It is also possible for Jetranger 2 TR blades to be fitted on a Jetranger 3. They are slightly shorter and have a bit more twist than the Jetranger 3 blades. More importantly, they do not provide as much TR thrust, so if you fly a Jetranger 3 with Jetranger 2 blades, you can run out of tail rotor authority in hover at altitude. Jetranger 3 blades have -127 or -131 as the last 3 digits of their part no. Jetranger 2 blades are -129 and -133....
On the main rotor head, check the Jesus nut is on and wire locked. Check blade hubs and blade roots for cracks (once again not a common problem for Jetrangers, but you never know).
So now it's started. Probably the most difficult part of flying the Jetranger. Once started, run it up to 70% N1 and switch the Generator on. Check the charge rate when flicking the switch, so that you know the generator is working properly. Check hydraulics, anti-ice if fitted and all instruments and gauges as per the flight manual
After one minute, increase to full throttle without exceeding 40% torque. Trim to 100% Nr, and complete the pre-takeoff checks.
When lifting off, the stick will normally need to be displaced slightly rearward and right when lifting and obviously, left yaw pedal is needed as collective is increased.
Limits here are 100% torque and 810C TOT. The flight manual lists 110% torque for 5 seconds as a non-intentional transient limit. I would suggest not to use it, unless it is to avoid crashing. If you can't hover with enough spare torque to get you through transition or out of where you are without exceeding normal limits, leave a passenger behind.
Normal Operation and Avoid Areas
At this stage, if you haven't heard of LTE, go and do some research to find out about it. If during any low speed flight or hover the helicopter begins to yaw past where you can stop it with yaw pedal, immediately increase forward airspeed.
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