South Herts Models
GLOWSWITCH and ACCESSORIES HANDBOOK
12-14 Bell Lane, Bell Bar, Hatfield-Herts, AL9 7AY Tel: +44 (0) 1707 654470 Fax: +44 (0) 1707 652446
[email protected] www.southhertsmodels.com
Issue 2
South Herts Models Glowswitch and Accessories Handbook
Contents 1
Who Needs On-Board Glow Support?
2
Installing the Glowswitch.
3
Setting up the Glowswitch.
4
The Cent-r-Lok Glow Plug Connector.
5
Support Battery Selection.
6
Two and Three Volt Support.
7
Battery Charging with the Master Charger.
8
Battery Charging with Other Chargers.
9
Multi-Cylinder Engines.
10
Adjusting Trimpots from the Underside.
11
Start-Up Boost.
12
Power Panels and External Starting Batteries.
13
Interference.
14
Miscellaneous Technical.
15
Disclaimer.
16
Warranty Terms.
Full List of SHM Products
Page 2 of 10
March 2006
Issue 2
South Herts Models Glowswitch and Accessories Handbook
March 2006
1. Who Needs On-Board Glow Support? Purists will tell you that if your engine is set up correctly it will never let you down. Absolutely true. Except that the correct setting changes constantly – particularly so for aircraft. Most engines have a reasonably wide operating range and it is usual to set the fuel mixture for the worst aircraft attitude – a steep or vertical climb. That leaves the mixture slightly rich in straight and level flight, but safely within the working range of the engine. Difficulties usually occur at the middle and lower end of the RPM range when the combustion temperature drops and combined with the cooling caused by the rich mixture leaves the glow in danger of being extinguished. In those circumstances engine failure is always a possibility, but the risk is greatest when the throttle is re-opened and the increased fuel supply chills the plug even further. To solve the problem came the idea of carrying a support battery and, using a switch, to turn on power to the glow-plug at a pre-set low throttle position – about 25% to 30%. This worked quite well, but the on-board battery needed to be big and heavy, because it is switched on, regardless, at low throttle. The other snag was that if you opened the throttle beyond the pre-set position, the glow switched off again. Not much help in an overshoot! Various improvements have been introduced over the years, but they still work blind – they don’t know what is needed at the plug – they just assume it. The same snags as before apply in an overshoot situation open the throttle too far and they switch off. Early in 2000 we introduced the Telco Intelligent Glowswitch or IG. The IG works differently from all the others. It actually monitors the glow-plug temperature! As the glow-plug temperature changes, its resistance changes minutely, and this change is monitored by the IG’s microprocessor. If the glow temperature drops below a pre-set value the IG will switch on the support battery for as long as it takes to get the plug temperature back to the pre-set level – whatever the throttle setting! The IG can be adjusted to suit the engine and, once set, there is no need for further adjustment unless you have made major changes (glow-plug, fuel or propeller). Consider this: It doesn’t overheat or damage the plug. It will not cause pre-ignition (detonation) by over advancing the ignition timing. Only a small on-board battery is needed. In an overshoot it stays in operation so you can climb safely away to re-join the circuit for a safe landing. External glow start not needed, but can be used if preferred. Low or no nitro fuel can be used (lower cost, less corrosion). Safer for the ‘plane, safer for onlookers. You’ve spent time and money on your model. Why not ensure its reliability. 2. Installing the Glowswitch. The IG senses the glow wire temperature by measuring its resistance every few milliseconds. If the glow wire has cooled from the set value, then the IG will re-connect the battery to restore the glow, but only when needed, so power consumption is very small and there is no over-advancement, pre-ignition or overheating of the plug. You might leave your engine ticking over for several minutes without the plug being heated, but when you snap open the throttle, the IG will briefly (if necessary) re-heat the glow. 2a. The IG will provide glow support at all times except at max and min throttle settings or when the Rx is switched off. When you switch on you must cycle the throttle stick to set maximum and throttle cut positions. The IG will be disabled (after 2½ seconds) when you fully close the throttle and when you fully open it for priming. The IG will store these min/max values until the receiver is switched off so you must do this every time you switch on the Tx/Rx. 2b. If you don’t need the automatic disable feature, then it is only necessary to disconnect the white signal wire from the IG’s flying lead. You won't have to cycle the throttle stick for every flight, nor will you need a Ylead, just plug the IG into a spare Rx output. This way the IG will remain enabled as long as the Rx is switched on, so don’t forget to fit a safety switch. If you want to enable/disable the IG from the Tx independently of the throttle, leave the white wire connected and use an output controlled by a slider – min and max positions will disable the IG, anywhere else it will be enabled. If you are good at programming your Tx you may be able to do this from a switch. Page 3 of 10
South Herts Models Glowswitch and Accessories Handbook
Issue 2
March 2006
Connect the IG (with or without the Y-lead depending on your preference for 2a or 2b above) as shown in the circuits below. Be careful to ensure that the crankcase connection is made to battery positive as shown. Many chargers and glow clips are wired the other way round and if connected that way the IG will be damaged and require factory repair. CH-IG Charger connector
Throttle Servo Throttle channel
CH-MC Charger
Black
IG-1
GP
+
Y lead
Receiver
Black + white tracer
Black
CL-1 Black
YA/PB Cell
OBSERVE POLARITY
Glow-plug
Trimpot
Red
CL-1 Red to crank-case
+
SS-HC
OBSERVE POLARITY Single IG (IG-1) wiring arrangement showing SHM part nos. Arrangement 2a is illustrated.
CH-MC Charger Black
GP 2 GP 1
Throttle channel
Receiver Spare channel
White wire disconnected
IG-2
+ +
Black + white tracer
Black
CL-2 Black YA/PB Cell
Throttle Servo
CH-IG Charger connector
OBSERVE POLARITY
CL-2 Black
Red
CL-2 Red to crank-case
+
SS-HC
OBSERVE POLARITY
Red LED is for GP1, Green LED is for GP2 Twin IG (IG-2) wiring arrangement showing SHM part nos. Arrangement 2b is illustrated.
3. Setting Up the Glowswitch Turn the glow level trimpot(s) fully clockwise, switch on Tx and Rx and cycle the throttle, trims and throttlecut from maximum to minimum. Move the stick to your usual starting position and start the engine. Select your tick-over setting and slowly turn the trimpot(s) anti-clockwise to find the position just before the engine starts to falter. When adjusting twin cylinder engines make small trimpot adjustments to each in turn so as to maintain a balance between the two cylinders. You may need to close the throttle more than usual because the glow support will raise the RPM. Repeat the adjustments until you are satisfied with the tick-over. When satisfied, snap the throttle fully open after a longish period at tick-over. The engine should pick up easily and quickly to full RPM. If not, add a little more glow support by turning the trimpot(s) clockwise a little and repeat the test. The IG uses its LED(s) to signal its status as follows: Flickering: The LED will flicker when the IG is testing the glow and will brighten when it is boosting it. A single repeating flash: No significance – this happens with some plugs when the engine is not running. It just means that continuous power is not needed to maintain the plug temperature. A double repeating flash: The IG is seeing less than 1V from the support battery. The support battery may be flat, faulty or switched off, or the wiring could be faulty or damaged. A quadruple repeating flash: The Rx battery is showing less than 4.4V – 6V users please note. The IG turns off when the Rx is switched off, so you can leave everything permanently connected, ready for next time. We strongly recommend that you fit a high current safety switch (SS-HC) as shown in the circuits above. There are often occasions when you will want to make adjustments without draining the support battery and it will serve to prevent accidents when priming, prop changing etc. It is also useful when starting ‘pumpers’ as the glow can be turned on once the pump is primed and the throttle set for starting. NB. In the above circuits the switch must be ON (closed) for charging. Page 4 of 10
Issue 2
South Herts Models Glowswitch and Accessories Handbook
March 2006
4. The Cent-r-Lok Glow-Plug Connector A poor plug connection will cost useful glow power and, worse, will cause radio interference. SHM’s Cent-r-Lok connectors lock securely to the plug and are supplied with 500mm of 24A rated Aero-HT silicone rubber cable ready fitted with 4.8mm push-on connectors to fit the Cent-r-Lok tabs.
Tap tite screw Spring- washer
T ab Crank-c ase connect ion tab
C lamp spr ing
Steel ba ll B arrel
Ass embled C ent- r-Lok p lug conne ctor
The Cent-r-Lok assembly.
The Cent-r-Lok comes as a kit of parts ready for assembly complete with 500mm Aero-HT cables. The assembled Cent-r-Lok fits securely, without the use of tools, to OS and YS plugs. The incorporated push-on tabs mate with Aero-HT cables which means they can be re-wired at any time – also without the use of tools. 5. Support Battery Selection Choosing the support battery size is easy enough. The following table gives a guide to battery requirements. The suggestions should be read in conjunction with your assessment of your own engine usage; battery usage will increase if you spend a lot of time at low throttle or with much throttle changing – as in pattern flying. All SHM batteries are fitted with 4.8mm push-on tabs and are supplied with 500mm Aero-HC silicone rubber cables and push-on receptacles. Work Load (Including Starting)
Single IG-1
Twin IG-2
Adequate for a normal club day
YA-160 1600 mAh
YA-300 3000 mAh
For a busy flying day
YA-300 3000 mAh
YA-450 4500 mAh
For a flying weekend
YA-450 4500 mAh
YA-900 9000 mAh
If, however, you can afford the weight, you may feel more comfortable with a larger cell. Here is a table of weights to help you in making a choice. Battery Type YA-160 (NMH) YA-300 (NMH) YA-450 (NMH) YA-900 (NMH) PB-250 (Cyclon) PB-450 (Cyclon)
Weight (grammes)
Weight (ounces)
25
0.9
55
1.9
85
3.0
160
5.6
178
6.3
270
9.5
Page 5 of 10
Issue 2
South Herts Models Glowswitch and Accessories Handbook
March 2006
6. Two and Three Volt Support Cells Multi-cylinder engines and multi-engines call for high current output while long cable runs (over 1m) may call for higher battery voltages to counteract cable losses. These requirements can be met by using 2V sealed lead-acid Cyclon cells as listed above. These cells can deliver huge currents with hardly any loss of voltage. If you have a long cable run, but only one or two glow plugs to service, you can avoid the extra weight of 2V Cyclon cells by using two standard NMH cells wired in series. Connected this way they will produce nearly 3V so care should be taken, when setting up, not to overheat the glow-plug. It is a good idea to remove the plug and adjust the glow (starting from fully anti-clockwise) to a maximum of bright orange and then mark the trimpot position as the setting never-to-be-exceeded. 7. Battery Charging with the Mastercharger NMH, NiCd and Cyclon cells can be charged using the SHM Mastercharger (CH-MC). This charger plugs directly into 220-240V UK 13A mains sockets. The charge rate required is selected by choosing the appropriate setting on the charger. The current control pod then regulates the charge. NB These settings apply only to the SHM Mastercharger. The mA figures in brackets are typical end-of-charge currents as a guide for charging other cells. Battery type
Overnight Charge (C/10) setting
Continuous Charge (C/20) setting
YA-160 (1.4V) YA-300 (1.4V) YA-450 (1.4V) YA-900 (1.4V) PB-250 (2V) PB-450 (2V)
4.5 (170mA) 7.5 (340mA) 9 (420mA) 12 (600mA) 7.5 (280mA) 12 (520mA)
3 (90mA) 4.5 (170mA) 6 (250mA) 9 (420mA) 4.5 (120mA) 7.5 (200mA)
Charge rate selection for the SHM Mastercharger
The Mastercharger comes fitted with a DC power connector that mates with the CH-IG on-board charging connector. 8. Battery Charging with Other Chargers For other makes of charger our separate charger connector CH-OC can be used to provide connection to the on-board charging socket (CH-IG). If you are using an ‘intelligent’ charger it is advisable make the charger connection directly to the battery. In the circuit below the battery can be charged while the SS-HC slide-switch is turned off.
Bottom view of SS-HC showing internal operation. For single pole use the two sides can be linked as shown
Full and part isolation of ‘intelligent’ chargers.
None of this complication is called for if you use a ‘linear’ charger such as the Mastercharger which can just be connected to the + and – screw terminals of the IG as illustrated in the basic circuits shown earlier.
Page 6 of 10
South Herts Models Glowswitch and Accessories Handbook
Issue 2
March 2006
9. Multi-Cylinder Engines A combination of IG-ls and IG-2s can be used for multi-cylinder engines. Setting up is done the same as before, by making small adjustments to each plug in turn. NB. Do not power the IGs independently – use only a single battery station as shown otherwise the IGs will not operate correctly.
Receiver
Black
-
IG-1
Black
GP
+ Y lead
Add choke FC-GM if needed
Glow-plug
Trimpot
Red
Red to crankcase
Add choke FC-GM if needed
IG-2
Black Black
+ + Red
Red to crankcase
Black
Tie both sides of the SS-HC together to increase capacity
GP 2 GP 1 Add choke FC-GM if needed
IG-2
+
SS-HC
Black
GP 2 GP 1
BATTERY
Throttle Servo
Black Black
+ +
Red to crankcase
Red
Multi-cylinder application
Use multiple Y-leads or make up a cable loom to provide the necessary branches from the Receiver. Each IG should have its own separate crank-case connection to the engine otherwise measurements made by the IGs will be distorted. Allow for the combined current of all glow-plugs when choosing the support battery. Reckon on a figure of 3.5 to 4 Amps per plug. 10. Trimpot Adjustment from the Underside It is sometimes useful to be able to adjust the trimpots from the underside. For instance if the IG is fixed to the inside of the fuselage then the trimpots will face inside the a/c making them hard to reach. However, all th IGs now have a 1/16 (1.6mm) hole under the trimpots. Use a pin through the centre of the trimpot to mark through to the other side. A precision screwdriver (no more than 1/16th diameter) can then be used to turn the trimpot from the other side of the IG. Remember that the sense of rotation is then reversed – fully anti-clockwise corresponding to maximum glow. Under no circumstances should any attempt be made to enlarge the through-hole as this could damage the circuit. 11. Start-Up Boost (IG-1b and IG-2b) Introduced in March 2006) Some engines benefit from a hotter glow for starting than is needed for normal glow support. All suffix b IGs are provided with a two-pin header for connection to the HH-SB start-up boost switch. The HH-SB switch is fitted inside the model and, when operated by a magnet from the outside, turns the IG fully on, ignoring the trimpot setting (3V battery users please note). A powerful disc magnet HH-DM is also available, ideally it should be fitted to a finger ring, thimble, glove etc so that it operates the boost when you hold the model for starting. NB the boost switch is most sensitive at its tip. No danger of leaving it switched on boost after starting and no interference with the appearance of the model. The operating range is approximately 13mm (1/2”) when using the HH-DM magnet and is not affected by non-magnetic construction materials such as wood or plastic. Making a magnet finger ring: Cut a strip of 16g aluminium about 3mm wide. Cover it entirely with heatshrink, and form it into a ring to fit your finger. Cut off surplus material and shrink a short sleeve over the join. Roughen up one face of the magnet and epoxy it to the ring at the join. Page 7 of 10
South Herts Models Glowswitch and Accessories Handbook
Issue 2
March 2006
12. Power Panels and External Starting Batteries Most people rely on the IG and on board battery for starting. However, power panels may be connected directly to the IG at [GP and +] for starting purposes as long as they don’t draw their power from a battery of over 14V (ie a 12V accumulator is OK). In all cases check polarity; positive to + and negative to –.
IG-1
GP
Black Black
+ External start connection
Red
OBSERVE POLARITY A simple external start arrangement for single cylinder engines.
Glow-plug 2 Blue
Solder Joints
Glow-plug 1 Green
Shrink Sleeve + Red GP1 Green GP2 Blue
Black 0V Red +2Vmax
Shrink Sleeve Switchcraft onboard socket
Neutrik jack plug
Socket: Switchcraft 35RAPC4BH3, Plug: Neutrik NYS231, Cables: Silicone rubber insulated 16 X 0.2mm
An external start for a twin cylinder engine is a bit more involved. The twin start circuit can be used for IG-1s by omitting the two blue wires from the on-board socket. In use, the on-board battery will be disconnected automatically when the jack plug is inserted. The external battery should be disconnected or switched off during insertion/removal of the jack plug. A kit of parts can be obtained from South Herts Models. 13. Interference There are no known interference problems arising from the use of the Intelligent Glowswitch. In fact IG installations have been tested to the standards required to meet the rigorous EU legislation on that issue. Generally whenever high currents are being used there will be an increased risk of interference. This applies more often to electric powered models, but can apply whenever the ‘signal to noise’ ratio is poor. A model flying at a distance may play up, while back at the flying site a range check proves OK. [How many times has that happened?] Here are some ‘Best Practice’ rules for aircraft installations: i)
Keep power cables separate as far as possible from control cables. Don’t bundle them all together – it may look neater, but it encourages capacitive cross-coupling. ii) Twist power carrying cables together into twisted pairs or triplets – this reduces their magnetic field. iii) Twist signal cables together into twisted pairs or triplets – this will reduce their sensitivity to magnetic cross-coupling. iv) In models where a lot of electrical noise is present or the ærial tuning is compromised (by an all aluminium skin for example) it will help to ‘de-couple’ potential noise carriers. This can be done by passing a suspect cable (this could be a servo cable or a power cable) two or three times through a ferrite toroid (FC-GM). These toroids are large enough to feed a servo cable through up to five turns, the more the better, without removing the plug (but even once through will help). FC-GM chokes so formed will cut down noise without affecting the wanted signal. Place them near to noise sources or near to the Rx or even both. v) DO A RANGE CHECK with the Tx ærial pushed down as recommended by the radio manufacturer.
Page 8 of 10
Issue 2
South Herts Models Glowswitch and Accessories Handbook
March 2006
14. Miscellaneous Technical The current draw of the IG-1 from the Rx battery is 5mA, rising to 10mA when the LED and glow output are both continuously on. The figure for the IG-2 is approximately double that of the IG-1. Current draw on the glow battery when not boosting the glow is equivalent to being on for 0.6 sec in every 60 (ie 1% of the time). The approximate weight of the IG-1 is 12gm, and that of the IG-2 is 20gm. 15. Disclaimer The information provided in this handbook is offered in good faith for general guidance only. Details given are correct to the best of our knowledge at the time of printing, but subject to change without notice as a result of manufacturing variation and design improvement. 16. Warranty Terms Products returned as faulty within 12 months of purchase: If due to a manufacturing fault: Free replacement. If no fault found there will be an inspection and return postage charge. Out of warranty and damaged units: If repairable we can quote for the repairs. Both the IG-1 and the IG-2 have been tested in typical installations (without the use of filters) and were found to comply with EN 61000-6-1: 2001 and EN 61000-6-3: 2001 and therefore comply with the emission and immunity requirements of the EC directive 2004/108/EC. As with any change or addition to an r/c system, you are strongly advised to carry out a range and performance check before operating the equipment.
Page 9 of 10
Issue 2
South Herts Models Glowswitch and Accessories Handbook
March 2006
Full product list
Description
Part No
Weight gms
Size (mm)
Telco Intelligent Glowswitch Single Version.
IG-1b
12
40x25x20
Telco Intelligent Glowswitch Twin Version.
IG-2b
20
60x30x20
Helping Hand start up boost switch
HH-SB
8
500
Helping Hand Disc magnet
HH-DM
3
11ø x 5
Cent-r-Lok connector pair with 500 mm HT-5 cables.
CL-1
17
500
Cent-r-Lok connector triplet with 500 mm HT-5 cables.
CL-2
20
500
Aero-HT airframe cables 0.5m - black & red.
HT-5
14
500
Yuasa AA size NMH 1600 mAh cell & HT-5 cables
YA-160
25
14ø x 50
Yuasa SubC size NMH 3000 mAh cell & HT-5 cables
YA-300
54
23ø x 43
Yuasa C size NMH 4500 mAh cell & HT-5 cables
YA-450
83
26ø x 50
Yuasa D size NMH 9000 mAh cell & HT-5 cables
YA-900
160
35ø x 67
Cyclon D size 2500 mAh 2 V cell & HT-5 cables.
PB-250
180
35ø x 67
Cyclon Tall D 4500 mAh 2 V cell & HT-5 cables.
PB-450
270
35ø x103
Slide Switch 12/24A.
SS-HC
3
28.5 crs
Regulated Charger for on-board NiCd, NMH & 2V cells
CH-MC
-
-
On-board charging connection
CH-IG
7
300
CH-OC
12
500
Ferrite noise filter (pack of 4)
FC-GM
15
20x12x13id
Installation kit - single cylinder - 1600 mAh cell
SGL-160
-
-
Installation kit - single cylinder - 3000 mAh cell
SGL-300
-
-
Installation kit - twin cylinder - 3000 mAh cell
TWN-300
-
-
Installation kit - twin cylinder - 4500 mAh cell
TWN-450
-
-
Glowswitch & Accessories Handbook
SHM-GH
-
-
Vulcan BMkII drawings
V-BMkII
-
-
Vulcan drawings non-EU airmail supplement
V-Air
-
-
Separate charger connector.
Page 10 of 10
