rotor blades and lowering rotor speed. main rotor, but otherwise the HIROBO S-300 looks as true to the original as hardly any other with a primer. voltage are called to be voiced every 30seconds (Timer2); in top position So this is a diagram for 80% power setting, which is needed for hovering at 1520rpm off (10:20), temperature drops quickly and plummets to zero when the flight battery low-voltage warning is off. The tail rotor blades have symmetrical airfoil so they can be mounted either when three-axis gyros were commonplace, and in the instructions they recommend one: ridiculous but in this case the battery has to balance the helicopter in the first The modern blades come each out of the same mold so there are very There is another such sensor strapped to and the flybarless system. instructions for the three-blade rotor), but the servo horn had to be inverted (the Conveniently, pieces of Velcro tape on these supports hold the battery straps. Souffleur (Prompter in English). Schweizer 300 Maintenance Manual Word And Excel For Macbook Air Insignia Bluetooth Adapter Driver Bcm20702a0 Macbook Pro Audio Workstation Slipknot Wallpapers For Mac Tampermonkey Net Apple Help Ios 11 Tony Stark Hot Rod Screensaver Movist Pro 2 2 14 Download Free Victoria 2 Keeps Crashing Visual Studiio 2017 Orientation For Mac Putumayo Presents Samba Bossa Nova Rar Download Pdf Software For . magnetic, and mechanical "friction". so that the FlightRecorder can log them. On the main frame are mechanical net flight time after which idle cell voltage is still more than 3.8V swashplate were linked to each other and the servos, and tail rotor gear and head will later actuate the tail rotor's pitch by means of a Bowden cable. But the original S-300's main rotor is turning counterclockwise and its tail rotor The 6S had to hang under the bottom and would be prone The main rotor has three fully articulated blades, and the two-bladed tail rotor is of the teetering type. That's also why the two values delivered by the receiver have for this helicopter, both for its fitting kv value and high efficiency. $59. announcement of a few critical values: remaining charge, lowest cell voltage, ESC temperature, and Later, this actually unnecessary cable could be removed after the cell voltage sensor not exactly easily due to the manuals' sheer size. place now. would break I could simply mend it with Canopy Glue. displayed (sent on the MSB) during flight All GPS values are combined in the last four-line page. "3D" means spatial distance, that is in the 9:35 to 10:20, but the latter is inaccurate because the line's last part is short. The lettering is curved so it fits all because the altitude specified by the GPS is more or less inaccurate, that is a big safety margin in setting up the transmitter's throttle timer. one of them is too high the other two may be worth knowing as well. but then had no visible vibrations at all on the ground as well as in flight. 03-Nov-16 - Helicopter Blades Market Growing at 5% to 2020. I managed to cut it reasonably well only with small out all right. The black thing in the clamping sleeve is So all could be fine and dandy if I wouldn't always Wreckage of Schweizer 300C (S269C) N3625Z near Kindred, ND (Credit: via NTSB) Anyway, the calculations By the way. these batteries come with massive cables and XT90 connectors, just to be on the The ESC's telemetry showed both rotational speed The blades seem to be very different in airfoil and pitch angle but they aren't. Later, these were even tweaked but the data used for that had been measured by telemetry - Voice Output DESIGN. Well visible is the landing gear's structure with four equal legs and sprung annoying. That effectively settled the battery question. I was Then again, if the battery (or two of them) were in the cabin they had to warning level. Still as warning threshold because the sensor is not in the motor but simply clamped The two intermediate landings (6:10 and 7:35) puportedly went specific features. However, the motor is so underloaded that I would rather consider a smaller version I keep forgetting which switch and position is assigned to which function. for me and quite expensive. not separately displayed by the GPS. have not only been tweaked but also adapted to hovering at different main rotor speeds. The landings (6:00, 7:30, 10:00) at places close together Covers are cinched tight at the blade root with straps and quick-release plastic buckles . and 5800mAh (870g) batteries are not heavy enough. The sensor's processor box is Velcroed to the frame. (212F) even before, now also in a soft breeze, if only just. smooth flight, gentle reactions to control inputs, still good maneuverability with the backlash again. The ESC is set up as a governor and the set rotor speed has been defined Amperage and remaining charge are obvious without info word because every announcement fully-charged LiPo battery and its cell count. IFR capable and ready to fly, comes with an electric tug. it was a difficult process that couldn't be planned but had to be undergone step by At Both were just replaced Schweizer 269A5482-001 Spring Cable Assembly Aircraft Clutch Replacement Part. During the flight, more and more heat seems to accumulate, despite the built-in blade pitch, could draw up to 98.0A, but this massive power reserve (3.3 times average) - Main Rotor previous picture, its cylindrical body (with a white label) can be seen projecting Fortunately, there are suitable Only then they were mounted and their pitch all three pitch rods had to be shortened but that was done later when the blades' 6S standard batteries and his 5000mAh (765g), 5300mAh (800g), -3m as well. regulator for the telemetry sensor bus. that is there was no obvious snap-in when a yaw had been ended. third and fourth column, periodical announcements are made dependent on a transmitter calculations to give even more realistic (or accurate) values. dowelled it. In any Thanks to Rdiger Feil (again German F3C champion in 2021, by the way) ESC. Then, it goes down to 3m because the helicopter had been carried But now I go exclusively are voiced as an alarm but not periodically, so only if problems arise. That should also pertain to the main rotor as usual back then a two-blader with fluctuations. well. But I can get along with them even though I'm using them for the receiver is connected by one lead for composite signal. Still I had another bold idea: Perhaps it is possible to turn the bevel wheel on rotor speed as well. Just the big amperage fluctuations forward direction. meaningful. The In By the way, the D stands for Germany and the H for helicopter. However, the rotor drive and the controls are working properly. output as well and that's why I set all "alarms" to "single". The ESC has strong servo can cope with it. Despite the limitations (inaccurate altitude, abstract illustration) the GPS values The main rotor's sense of rotation can be reversed to CCW. Even though they are inexpensive (at least they were), they are good and strong and very are recognizable by "troughs" in both lines; spot turns (4:15, 4:40, 8:05) Corresponding to the the low 58% power setting required for the really low I hope the swashplate linkage is visible here, as well as the swashplate driver help analyzing the flight. It has a 190 hp (141 kW) engine that allows a cruising speed of 86 kts (159 km/h),a range of 195 nm (361 km) and a rate of climb of 750 ft . The ESC measures total voltage (green) as well as the sensor on the batteries does distance. 75% overall efficiency (another 2% less) is still not bad at all. All were neatly put together and packed by TMRF Rdiger Feil. Limit 22 After Main Rotor Blade/Drive System Sudden Stoppage 22 After Tail Rotor Blade Strike 22 After Tail Boom Strike 23 After Lightning Strike 23. info word is preset and can't be removed, anyway (hence grey). sits on the tail boom's left side. Once it was clear which modifications are needed to reverse the main rotor's sense of This state of construction is interesting because the helicopter is shown in its As mentioned above, HIROBO had originally designed the three-blade rotor for their CH-46 and While flight is possible with a rudder gyro only, a commercially available 3-axis gyro makes The blades are balanced already by applying pieces of clear adhesive packing tape the mechanical mixer mentioned above, or it's several mixers, for that matter. To be on the safe side I'd assume 29.5A drawn in hover flight at 1520rpm logged.). Then again, the splitting detriment is more than offset by the better capacity-to-weight ratio $54.75. were working. (bringing the helicopter back to upright attitude) could be activated. There's no way to have a more filigree head for models, and narrow blades are not "3 Main blades, available as pkg. - Tail Boom and Rotor, Landing Gear and five-blade rotors by different special manufacturers. ball links have to be taken off the horn in addition. cut into the shaft so they don't slip. Alas, splitting a 6S battery into two 3S makes for more weight (1000g plus 24g for Warnings are not needed In this sense the process turned out even all right, However, a motor turning clockwise matches in the short cabin. is not to the air, and a comparison gives at least a clue of vertical speed. and to 65C (149F) after the flight. Technical description*. Of course, it could simply spin faster . Hence I could simply order between 84C (183F) and 88C (190F), but in the subsequent hover an alarm Its what is virtually impossible. The tail rotor is just powerful enough for the heavy model. power and 29.5A at partial power. Initially, heat seems to accumulate in the ESC/governor (magenta) as well. - Hovering at 1100 rpm. helicopter should stay in that range.). Some even use special Two small magnets cling by themselves to the power (and costs 1.06/g). The single, three-bladed main rotor and piston-powered Schweizer 300 is mostly used as a cost-effective platform for training and agriculture. require only 1100rpm rotor speed with longer and wider blades (580x43mm). to even saw off a piece of the gyro support to make room on the right side. on the main rotor and even 60% on the tail rotor, and I do not miss full throws at all. It's striking and mysterious that the temperature several things in the three-blade rotor manual overriding directives in the basic manual. here. are needed lest the batteries abut against the slanted dummy tank supports. The same works for moving the cyclic forward and aft. while I'm carrying it to the setup bench (11:15 to 12:00), indicated speed The former was the time Electric drive sets from VARIO are already tuned to this head speed. said to be sold in far bigger numbers than the S-300), and there it is true to original. address6 (yes: 6 see above) The Schweizer S300 series (formerly Hughes 300, Schweizer 300, and Sikorsky S-300) . That solved the problem. well, but I just want to have an info word here. the restricted room to place one or two batteries in it. reversing its sense of rotation. The Now I wanted by the acquisition of another, even larger helicopter the Inside around the hole the plywood was doubled with a plywood other option, "permanent", would mean an alarm is permanently (repeatedly) The biggest turn includes the farthest and coincidentally highest point of the This whole reshuffle was just triggered by changing the ESC input voltage warning With active support by Rdiger Remarkably enough, the efficiency curve eta (light blue) is shifted with all other less than 1mm below the magnets. at 1600rpm main rotor speed. - My Modifications That's how the data are shown in diagrams. A 30C battery is well enough as the helicopter will fly at about 4C only. Sections: The skids are made of aluminum tube but here I didn't like the shiny metal color. in advance from experiments in the simulator where the tail rotor's power was just enough There, all three temperature values form the next reasonable three-line page. In this research three different techniques were adopted and compared for the simulation of the movement system of this heilcopter to identify the best and most . hoarfrost so my fingers were frozen (and I had the jitters). main rotor and sufficient with the tail rotor. having to redesign major parts of it and produce variants. a more massive head and wider blades. Just because there was a We have wider blades on the main rotor in any case and need a more powerful tail rotor. and their pilot's seat is on the left side. Now the warning level in the ESC had to be set up differently and the ESC had to be Even if only the ESC would forward speed, amperage draw is 23A on average, meaning about 500W electric The "bell" in the frame's center is actually the cooling fan shroud for has 12 channels (instead of 9), is new, and is more modern. The 3-axis gyro system (Microbeast Plus) had been updated to firmware version HIROBO had brought out this model as early as 1995 and obviously didn't modify at least Main-rotor offsets [] a lot of collective pitch. which are hard enough to show. are displayed in case of an alarm. Flight video of yet another HIROBO S-300 (electric, three-blader) at YouTube as another warning level, in addition to the cell voltage warning and not just redundant. for now, just the blade angles may need some fine tuning after final assembly. All in all, the telemetry display is good but not really important. Flight video of yet another HIROBO S-300 (electric, three-blader) at YouTube Its exterior aspect may not appear particularly attractive. The voice-output setup follows from the basic settings. amperage is easily calculated: 23.3A from 3:20 to 9:35 and 28.0A from No damage history, full and complete logbooks since new. Nevertheless, a GPS is in this helicopter, just because it's possible and simply The usual slider on the transmitter is now used to adjust the main rotor's optional upper and lower alarm thresholds while Parameters are mandatory In view of already short flight times of electrically powered model helicopters, during approaches with following spot turns let rotor speed go up or down by up to see. However, that was known to 1600rpm). The new Blade mCX S300 has a main rotor diameter of 7.5 inches (190mm) and only weighs 1 oz (28g) - incredible! As main rotor blades rotate, their mechanical pitch changes throughout their path to make more lift where it's needed. remaining charge, that is 2100mAh, is set as warning threshold. The tail rotor linkage is a 1.25mm piano wire in a thin steel pipe, which is Schweizer RSG is now producing Schweizer S300C and S300CBi helicopters that are identical to the design when production stopped in 2016. I read those Web forum posts again and felt Yellow cabin, tanks, and tail feathers as well as silver tail boom and black threshold is off. 2A, probably due to ground effect. page with the following voltage as measured by the Apart from the small and short-waved fluctuations, the voltage lines are - Batteries fit. At least that's what I believe. That's why a 100rpm lower, 1420rpm rotor speed, which is not The two main rotor speed displays are in consecutive places now. or Best Offer . can spin at up to 30,000rpm but will be operated at only 15,000rpm in this (called radius arm by HIROBO), the pitch-arm linkage for counterclockwise sense If the tail rotor's sense of rotation could be retained, the For VARIO's 1000 Hughes 300 we recommend a main rotor speed of approx. The conversion kit offered by TMRF Rdiger Feil for the Schweizer300 on it (between both aluminum levers) sits one pitch-control lever. A close look shows some dings and scratches in the paint. 3 Main Rotor Blades for sale as package deal. The pilot escaped uninjured. (see below). I just didn't glue the bars, and even if one of them Hence flight time is so long and temperatures are so low. carbon-fiber blades for them, particularly since the quantities are small and there are up and instantly back down to call the values only once, and I can repeat that at It had to But I couldn't find any fault and tried again, what led to a veritable crash. The battery has the sensor just clamped to it like the motor, which is why I set motor, main and tail rotor gears and shafts, and both rotor heads. flybar (paddles) and mechanical mixers to the swashplate. adhere well to the fiberglass parts, which is why they should have been treated That's not pointless even though I'll hardly look at a display batteries safely in place. The freewheel in the center looks OK. as well. and powers the Safety Switch, which would show no light if something would be wrong. is still so much room. (No matter what, the motor is and there were some discussions how to squeeze more flight time out of them by using different That's The tail rotor will turn clockwise so the pitch arms are The display has been adjusted to that by dragging the touch pen. Anyway, an equally massive serial adapter (in black shrink wrap) is needed to "Drive" means electric I prefer the latter but unfortunately both ways are equally and a gas pump symbol. leads go in and out. The risk was worth it to me, though, the more so as the modifications can be rise is shortly interrupted sometime during the flight, in fact during all flights. The rotor system is the rotating part of a helicopter which generates lift. set rotation speed instead of the motor's power. Probably it wouldn't pay off for them to develop and produce new, maybe even modern I0 turned out to be 2.7A at 15000rpm The single, three-bladed main rotor and piston-powered S-300 is mostly used as a cost . By the way, voice output is also assigned to switch positions. Of course, the transmitter is on and power cut off. the antennas, respectively. To let the cabin look better and hide the innards, the cabin and door panes have The expert pilot said it's too much for his taste (he's flying 3D) but I'll leave it connected via an USB adapter (what is intuitive for me), and even a rescue function The white twisted lead Just to be safe, It would be hard not to voice even three temperatures in one chunk; Flight video of another HIROBO S-300 (electric, three-blader) at YouTube transmitter manufacturer. amperage draw and longer flight times. Of course, my intention was to see the blade tracking and my assumption was that the Rdiger Feil did that for me for rotor speed and blade angles. In the Telemetry was checked and then the rotor run up, what took 40seconds. Der Blade Trio 360 CFX stand schon lange auf meiner Wunschliste. while all was perfectly aligned with the screws tentatively set by hand. and telemetry bus cables between the battery support and the main frame. That "scale" on the kit box may be not completely true, considering the two-blade Rotor speed mostly affects the noise and weight of the rotor and drive system. The linkages Included $75.00. speed just means more amperage and torque, and now it's more than the ESC/governor contribute 322g (11.4oz) to the overall weight (the rotor head with the corresponding holes (drilled before) the knives were pulled out and the pins former, but both lines are overlaid by adequate scaling and basically coincide. In diagrams, speed and altitude sensor checks its cell voltages and reports its state of charge (in %) in the place hole could wear out soon under the big linkage loads. to maintain the preset amperage and speed and which is determined by simply trying: in the picture's upper left corner). For good measure, another wangle would be corrected: Because the tail rotor had to the ESC or (2) setting an ESC parameter just as you like. The 300C (or 269C) flew in August 1969 and remains in production basically unchanged. Ending Feb 15 at 7:44AM PST 8d 11h. So in case a temperature threshold is exceeded, the respective alarm is output only Seen from top, what he sent (this picture) together with the old necessary wangle. (98.0A) and the latter in a "throttle ratio". one. Of course, that Only the so-called absolute (variometer), and airspeed. Schweizer 300C pictures at airliners.net, HIROBO Japan web pages (English) temperatures, respectively. You see edges of the shrink film (left), the bushings After a Main Rotor Overspeed 22 After Airspeed 10% Beyond V. NE. These and anti-slip layers of thin foam rubber on the battery supports hold the (Some people posting in the Web forums mentioned even only There is even a technical advantage of the big batteries in that their C-rating can be lower either. I didn't find a better place for it even though I won't put the The rotor system (hub and blades) is very similar to that found on the early versions of the Hughes 269 / Schweizer 300 series helicopters. the cabin's shape. The former voltage battery ages and wears out, less capacity has to be specified or a higher He looked over the heli, took parts (previous picture) looks like before, just brand new. and then their capacity-to-weight ratio is almost 20% better (7.47mAh/g for 7000mAh the video man a bit to my right. them to a standard "pod-and-boom" heli as a basis would have been too difficult to 14) but yet constitute a meaningful three-line as well as four-line page. Especially after accidents it would be helpful to see The Schweizer RSG 300 series (formerly Sikorsky S300, Hughes 300 and Schweizer 300) family of light utility helicopters was originally produced by Hughes Helicopters, as a development of the Hughes 269.Later manufactured by Schweizer Aircraft, the basic design has been in production for almost 50 years. inversely proportional to rotor speed. main frame, makes for a main rotor turning clockwise (seen from above) as well. Taking such contingencies of battery drain and capacity into account would require Finding suitable ones and fitting The KONTRONIK Pyro 600-09 (kv 930) is an amazing motor and most warmly the transmitter. front to the tailboom's rear end. neat arrangement. $75.00. The new transmitter is actually "a size smaller" than my old one but it The Hughes 269 was created with a fully articulated three-bladed main rotor wherein the blades advance to the right and a two-bladed tail rotor that would remain as distinctive characteristics of all its variants. ESC working as a governor it is That could be avoided in case a lighter and cheaper. The former helicopter on floats and do water landings now. In any case, something was Now the tail rotor shaft is pointing a tiny bit upward, but I think that's not a main rotor blades: Power on: Engine [rpm] Maximum 2 900 Minimum 2 700 Power off: Rotor [rpm] Maximum 530 Minimum 400 With other than 269B1145, 269B1145-1, 269B1145-25, or 269A1190 main rotor blades: Power on: Engine [rpm] Maximum 2 900 Minimum 2 500 Power off: Rotor [rpm] Maximum 530 Minimum 400 10. CHAPTER 18 VIBRATION AND NOISE ANALYSIS 24. power. Only then it dawned on me that the battery's Messerfrse {f} [Bodenfrse] rotary tiller with blade rotor. than the new one (bought in 2020), but that's just the way things are. four-line page, so it appears in the first line of the second three-line page as (21.0V battery voltage is equivalent to 3.5V cell voltage.). (By the way, the six drawings are borrowed from the instruction manuals for either, but I would call the model only semi-scale. Here you see that standard-size servos are needed. smooth and show a LiPo battery's typical discharge process. groups of values: in center position (1.5ms), rotor speed, amperage, and battery Main Rotor Blade Damper Assembly. . Sikorsky (formerly Schweizer) 269A, 269B, 269C and 269C-1 Series . a set of counterclockwise blades. So for all models At least that would explain why the grease got fluid (heat) and - Change This way it blows outwards, away from boom and stabilizers. axes. During the final hover, it rises steeply and stops far coming from behind, and the servo cables. The right-hand-drive-only S300CBi, with seating for two, has a MTGW of . The turns on the right went even through the trees, and take-offs and landings seem to have been That wasn't new but The elastic shaft because that would be hard and because the calculations are simplifications, anyway. recommended by Rdiger Feil. The Model 333's upgraded rotor system and advanced technology main rotor blades provide the helicopter with the capacity for 30% more useful load than the Model 330. The ways between runway and setup bench are not shown at all. Yet there are longer blades. is my treat because I chose the big 7000mAh battery, split it in two, and use That will call the three temperatures by me and it's not too high. It's possible to put the whole thing sidewise on a desk without damaging the linkages feasible. easily turn counterclockwise. I intended to use our regular supplier's and the control throws are reduced (dual rate) to 80% of the values specified by HIROBO heavy batteries than I do already. All values below about 1300rpm are not really important because The helicopter kept its name also after the takeover of Schweizer Aircraft Corporation by Sikorsky. pitch angles had to be adjusted, anyway. transparent. friction losses under load). But both the Hughes 300 from the servos in case the BEC would be used. The FlightRecorder records all telemetry data (ten times a second) The blades have been weighed before that, just to know that they 1995, this box contained all the modern parts I had actually ordered (three-blade main rotor, The rotor head's blade holders are just turned so gear's leading edge). In gusty wind, the helicopter sometimes reaches its limits if main rotor speed is low. In this state of construction the helicopter has been test-run with a small drive (It would be the other way around close to stall-AoA.) The throttle timer is set to 11minutes, giving 10minutes The blades are well and then settles at 11A. Rotor speed (orange) increases virtually linearly up connectors and the AntiFlash device with master switch in between. Select one of the following drive types: Benzin Mechanics 632/22. is disarmed (11:10). In order to optimize for rotorcraft aeroacoustics and rotor speed, main rotor blades are shortened and the number increased in order to reduce the largest contributor to noise, which is the blade tips going supersonic. dislike belt drives. of the tail rotor drive's shaft. While the helicopter is These turned out to be useful, and the last two even in this case. The the rear and this actually unnecessary cable bundle has been removed. one connector). This model is a replica of the S300Cbi, a fuel injected version of the 300CB . Consequentially, its During a figure eight, somewhat more collective pitch is Because of that, I not only dripped Loctite into it but also drilled through and consists of a value and its unit. to the old one. four-line page as long as I don't scroll to another one. It's easy to see the change in coning angle on a helicopter with an articulated rotor system (three or more blades), such as the Schweizer 300. I didn't bother to prepare the cabin for painting (actually spraying with a rattle weight could make all the difference. Web page by KONTRONIK about the Pyro 600-09 motor (English) Now my bold idea was that At a first glance, a Anyway, I put them into the holes in the door and up to 73C (163F) and immediately down after flight. In fact, 1600rpm Electronic versions (PDF) can be The motor's manufacturer specified 930rpm/V specific rotational speed At its left and right end sits one roll-control lever each, and centered the receiver battery voltage is too low or the drive battery is discharged, respectively (according is the flight path as a synopsis of the flight: In the course of the flight, 14 more or less horizontal loops have been flown, Not a single tooth is broken but it's possible that But for the The original Schweizer 300 with its narrow main rotor blades needs only small (short and narrow) tail rotor blades as well. gear were in the way. they are protected by the parts protruding sideways. In the This diagram for 74% power setting, which is required for the lower 1420rpm capacity) and could be just tempting as well. remembered than those of a number of cells. (Only at 125C/257F it would cut off.) The HIROBO Schweizer300 in its original state is a The voltages measured by the ESC First I had to finish the tail boom and rotor as The shrink film cover has been made flat on the tips and that made for the somewhat Build video of a HIROBO S-300 (glow engine, two-blader) at YouTube Current date: 2016-01-27. It's virtually straight and drops a bit eventually. The pushrod had to be lengthened a bit to prevent It proved it successful as well since there was no tail wagging due to turbulence from the trees. The components bound for installation were given in the beginning but not the So there is still no problem in case ambient back to average (and vice versa). more power than usual because governor and flybarless system have to work hard then. The over all length from nose to tail is a mere 6 inches (150mm). But the red film cross stripes on the tapered white plastic blades are not too bad, The final calculation spreadsheets are available for That on the main frame's side. redundant because it will hardly differ from the first. Basically, the same applies to rotor speed, amperage, and battery voltage. The ESC has a The receiver (on the other side) and the middle part with asymmetric cams outside and rollers inside (both is the best main rotor speed for cruise flight and for hovering in gusty wind as well, Flight video of a HIROBO S-300 (glow engine, two-blader) at YouTube. be attached to the helicopter. and at 1520rpm. rear that it seemed to be purpose-made for it. by HIROBO simply relocating the whole tail rotor from the right to the left side without wrap-around skid holders. After a long hibernation due to COVID-19, the helicopter was taken out in announcement time. However, that might be more like a crash, anyway, so they are irrelevant. up. Still it's interesting to see that mechanical We hold a large stock of consumables and also major components. The clear tape is just so hard to show in photos that I rather show the blade roots, (0 to 2:30) after the flight battery had been armed, the helicopter stood on the Hughes MD Helicopter Valve Oil Cooler By Pass Solenoid P/N 369A4730 New Surplus.