StanFoster
Active Member
- Joined
- Nov 16, 2003
- Messages
- 17,142
- Location
- Paxton, Il
- Aircraft
- Helicycle N360SF
- Total Flight Time
- 1250
I was asked by a Helicycle enthusiast here on the forum to list the modifications I have done to my helicopter. The following are the mods I have done to my machine. I will list my mods in different categories such as turbine, instruments, frame, controls, etc. Many of these mods I feel increase my chances of avoiding forced landings. Nothing replaces practicing autos however! Also, I am doing this on a cellphone and cannot organize these into neat columns. I will edit these on the computer after the holidays. This is a partial list and I will add as I have time..................Turbine mods. 1. Main fuel solenoid was changed from NC(normally closed) to NO(normally open). This was one of my top priority changes. Originally, I needed to have a constant never interupted 12 volts keeping the fuel on. Now I need 0 voltage and instead need 12 volts to shut the fuel off. All Helicycles from now on will be configured this way............................2. Backup battery system was added to supply the necessary voltage to the governor to operate the turbine. I have a small sealed battery that is charged by the main system, but is isolated by diodes so that even if the main system has a major short, that short will not draw voltage from the backup battery. The backup batteries voltage is checked on each prefliht verifying the battery is charged and ready for backup. ................................3. Main fuel solenoid also powered by backup battery. I was having some turbine starts acting like my MFS was turning on while the starter was cranking the turbine up to speed. This MFS needs a certain amount of voltage to keep it closed. When the starter is engaged, the voltmeter goes way down. Now with the backup battery also powering the MFS and isolated by diodes, all its 12 volts keep the MFS closed while the starter is drawing down the main voltage. ..............................4. Start/Fuel power is also supplied from the backup battery. This again keeps the exciter and start fuel solenoid happily powered with 12 volts while the turbine starter is drawing down the main voltage.......................................5.The turbine initially had two return oil scavenge lines returning both into a "T" then one return line to the oil reservoir. Reports of possible oil foaming causing inconsistent oil pressure readings seem to be my case also. I ran another return port so that I now have 2 return lines going back to the reservoir tank. There was also a loop in the oil line coming from the oil reservoir that was eliminated. Since these modifications, my oil pressure readings no longer fluctuate between 20 and 45 pounds, but now stay rock steady between 42 -45 pounds...........................6. Turbine low oil pressure light. Its nice knowing I have a bright red light ready to come on should I lose turbine oil pressure in flight........................................7. Main transmission low oil pressure light. I had no oil pressure gauge anyway, so its nice to have a red light telling me to land immediately. When I start my turbine, I watch the turbine oil light go out. When I start spinning the rotors up, my main transmisssion light goes out at around 50 rpm.......................8.Fuel control arm lights. I placed two micro switches on my fuel control arm that activate amber lights in my dash. The first light comes on a tad before the fuel control arm is at its max fuel position. The 2nd light comes on at full fuel. This is my liitle crutch telling me when I am asking the turbine to do all it can do. It takes an OGE hover on a hot day, or a very aggressive pull of the collective to activate the first light. Since installing these lights, I have only seen one flicker during an OGE hover on a 95 degree day. It is comforting to have not seen these lights come on during fasirly aggressive takeoffs. The catalyst for these lights was from having that first flameout when I pulled the collective like an ignoramus ape m. I would bet $500 that had I had these lights installed then, they both would have come on. I flew too conservatively after that flameout until I installed these idiot lights, which deservingly were named after me pulling off such an idiotic stunt............................Airframe mods...........1. Cross cable bracing on my landing gear. I had heard not to do runon landings with a Helicycle as the landing gear folds up easily. I wanted to do runon landings if I had to. 3 days after I installed these cable, I had my flameout which ended up as a 40 mph _200 foot skidding runon landing on sod. I believe the cables no doubt saved my ship. If you study the U brackets welded to my longerons on the airframe, both sides have a very slight twist in the direction the gear would have folded had the cables not intervened......................2.Cyclic boot. I found an accordian style cyclic boot that gives a nice even resistance to the cyclic in all directions. It has a natural neutral position that could have been a nuisance had it held the cyclic in the wrong spot when spinning up the rotors. As luck would have it, it holds the cyclic in the sweet spot keeping the swashplate happy.................3. Installed a storage compartment cut in under my seat pan. Nice compartment for basic tools, map, lube, etc. Also, it is made out of clear plastic and I can take a flashlight and look at my cyclic controls that otherwise couldn't be seen. It can be taken out also to be able to do some minimal checking also instead of unbolting the cabin bottom..................................Fuel system mods............1. Went with 3/8 in. fuel lines instead of 1/4 inch.............2.installled a nice fuel selector valve with positive detents and with the capability of either gravity filling my aux fuel tank or filling it via the fuel pump.......................3. Installed an aux fuel tank with a transfer pump. This allows me to burn off my top tank which is mostlt aft fuel, then trannsfer my forward aux fuel to the top aft tank. This cuts my CG shift in half even though the full CG shift isn't that bad anyway. I only use my aux tank on cross country flights, and having that extra 5 gallons makes a big difference..........................4.Installed an Adel gascolator. Love that thing! I can easily take sump samples, take the bowl off and clean the fine mesh filter. I discovered algae growth on half of the filter screen before I was using biobor in my fuel. I consistently monitor my free flow fuel to my turbine fuel pump. It normally is 25 gallons per hour just by gravity draining. I caught it only doing 20 gph, and immediatelyfound the screen in the gascolator half plugged. I got educated on adding biobor to my fuel barrels, and haven't found anything but clean fuel in my filter screen since..........................5.installed an in the cabin fuel level sight tube. I placed a red floater inside the clear fuel line and love this simple and very accurate way of telling me exactly what my fuel onboard is. I can run it down to the last gallon if I had to and know I have one gallon left........................6. Configured fuel sumps in my bottom two fuel tanks. The standard fuel outlet is around 2 inches from the bottom of these tanks. I placed drains in the triangular sections at the very bottomof these tanks. I can drain out a pint of fuel on each side. I have two petcocks to occasionally do this. I could take on a quart of water and drain it out.........................7. Installed a clear vent line from my aux tank to vent to the top of my main tank. When I am filling my aux tank, I simply watch for fuel flowing through this vent return , indicating the aux tank is full......................8. Added a 2 inch filler hole to my main fuel tank. It will accept the 1.5 inch JetA nozzles at airports, but not the duckbill nozzle. I carry a section of bicycle inner tube for an adaptor for a duckbill nozzle................................9.Added a fuel shutoff just ahead of the gascolator for easy cleaning of the gascolator. The valve arm is safety wired to the on position and tied off securing the bowl of the gascolator as well......................Instrument mods..............1. I added a bleed air valve installed next to my ASI. My ASI was reading around 10 mph too high. This bleed air releases more air pressure out of the pitot line the more you turn the screw. Only had to calibrate it once with my GPS averaging two speed runs into the wind, then doing a 180 and averaging them. I for fun check my ASI and it is within 2-3 mph all the time..............................................to be continued.............
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