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Old May 26, 2012, 11:02 PM
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Simple on board glow driver

I'm thinking of simple ways to heat the glow plug in flight....without spending $50 for a digital driver. The classic way is a micro switch that turns on the battery when the throttle is at a set point. Simple in concept but sometimes finicky in operation.

I saw one guy who just used a switch to turn on the circuit and left it on for the entire flight. This really sounds like a good way to do it...at the expense of having to charge the on board battery more often. http://www.geistware.com/rcmodeling/...low_system.htm

Another article showed how to setup the circuit so that once the engine is running the current to the plug is reduced, thus prolonging the battery power between charges. Here is a link to the article: http://www.rcmplans.com/issues/reque...082000-1-1.pdf
The basic idea is to add a power diode in the circuit to drop the voltage by .6 volts. I'm thinking that this circuit without the micro switch feature might just work very well.

Any thoughts?
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Old May 27, 2012, 09:41 AM
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I saw a post somewhere, where the author used full time glow heat and 0% nitro fuel; said it worked great. One thing about the battery/microswitch method: This system will always light up a dead cylinder in a multi wheras the fancy solid state units often do not.
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Old May 27, 2012, 10:44 AM
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You could use a 2volt "D" size battery (Rechargeable) and a Fox 2 volt glow plug.
http://www.atbatt.com/sealed-lead-ac.../0810-0004.asp
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Old May 27, 2012, 01:08 PM
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Why would you change plug in order to use a heavy lead battery?

NiMh batteries are lighter and have correct voltage for the regular 1.5V plugs.
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Old May 27, 2012, 01:28 PM
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There's a TWO YEAR OLD thread here at RCGroups about lead-acid cells & glowplogs...

Dear Broken Wings:

The PIPE Here...you MIGHT want to get a look at a two year old RCGroups forum thread that touches on that VERY subject (but NOT IN a model)...

...as I've used that EXACT cell you're speaking of to get my four strokers going in the past, as an example of my expertise at whipping up my own "homebrew" field support equipment for four-stroke RC flying...it's something I brewed up entirely on my own nearly 30 years ago, and because of a very special semiconductor device as the ONLY solid-state device in my design, I CAN use ordinary four stroke glowplugs (OS Type F) with it, and it simply NEVER blows one at any time.

It's mostly my responses as posts number SIX, EIGHT and NINE in that linked thread that I'm hinting at...read, learn and most of all ENJOY !!

Yours Sincerely,

The PIPE....!!
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Old May 27, 2012, 02:06 PM
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Quote:
Originally Posted by 706jim View Post
I saw a post somewhere, where the author used full time glow heat and 0% nitro fuel; said it worked great. One thing about the battery/microswitch method: This system will always light up a dead cylinder in a multi wheras the fancy solid state units often do not.
A warmer plug will advance the ignition and you even may get pre-ignition which can overheating, and in extreme cases damage to the engine.

Top Flite Taurus glowplug engine starter battery (0 min 54 sec)
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Old May 27, 2012, 05:17 PM
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The idea of an on board glow has been put to use with positive outcome for many. Not a universal need but it some cases it really works well . As already pretty well known

Some flying styles benefit from the reliable extended idle , it is also so convenient to simply turn on your radio , set the transmitter to a suitable point , flip the prop and fly. No need to haul loose parts up to the plane , its all there !

Switching the plug off at throttle settings above idle is the better way to go in most cases.

You have already mentioned the inexpensive micro switch method. The switch system is quite trouble free if it is set up well from the start Usually a second series switch is used in order to positively shut off the glow when not in use.

The question of "need" for on board glow for extended idle is a moot point IMHO however . While most anyone can get a decent, reliable idle without added idle heat , the on board glow has the potential to make the best setup engines idle even lower,longer . ..but that is just a bonus .
Often over looked is a safety benefit from not having to connect the outboard glow.

Another method you already mentioned is a simple pulse width activated switch.
You could build your own but for most people the $30 to $60 units on the market work well and by the time and cost are considered ,pretty cost effective. PM me for a reccomendation and link to a very well made , local unit at a reasonable price .
A side benefit of the electronic switch is that it automatically turns off the glow when the radio is switched to "off"

Rather than a heavy 2.0 volt battery and the need for voltage drops or current limiting, the trusty old 1.2 volt NiCad can perform well and makes plenty of heat for standard 1.5 volt plugs. The 4AH capacity "D" size NiCad is usually quite adequate for very long flying sessions , provides a lot of capacity at fairly low weight and a single cell is generally more satisfactory than multiple cells in parallel. The single "D" NiCad is a very robust storage device .

[IMG][/IMG]

Here is a photo of the flight line box.


Note there is a wireless glow driver charging on the modified power panel . The power panel adds considerable versatility.
First , of course the standard plug wire setup, second the direct to plug wireless glow driver with an ammeter built in . Thirdly , the same connection that allows for charging the wireless driver can also serve to charge the on-board glow . Not often needed ,but the capability is there for those real long flying days . Also , having the charger handy there is less need for extremely large batteries as some use with their wireless glow drivers .

All of that said , I will add that only one of my planes has on board glow . It is a Saito 4 stroke powered trainer. this is a loaner/student plane and the glow was initially intended to simplify operation and provide a measure of safety . This it did very well ! The bonus of being able to idle almost forever , at very low speeds then throttle up instantly, repeatedly was just a pleasant dividend.

Not here to say "Do it my way" Just sharing a few methods that have worked for myself and others . Your needs , choices and results will of course vary .

Best wishes, feel free to PM
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Old May 27, 2012, 05:32 PM
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I have a 1/4 scale Super Cub,with a fully cowled engine,and an inaccessable glow plug...I installed a remote wire to the plug,and a "D" cell inside the plane.I put a micro switch in the side of the fuselage,and when I'm starting the plane,I just press the switch.....nothing to carry or hook up,can't accidentally leave it on.
I haven't needed on board glow for low idle though.O.S.91 4 stroke.
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Old May 28, 2012, 07:52 AM
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In the Netherlands we can buy penlites in the super market. These are available of 2700 and even more mAh, Two parallel? 5400 mAh!!

part 2 (2 min 31 sec)


The penlites shown in the video are the best for camera and glowplugs but also transmitters and receivers.
Matter of investment, experiences and standardization.

.
TF
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Old May 28, 2012, 08:36 AM
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Quote:
Originally Posted by Gary Cee View Post
The idea of an on board glow has been put to use with positive outcome for many. Not a universal need but it some cases it really works well . As already pretty well known

Some flying styles benefit from the reliable extended idle , it is also so convenient to simply turn on your radio , set the transmitter to a suitable point , flip the prop and fly. No need to haul loose parts up to the plane , its all there !

Switching the plug off at throttle settings above idle is the better way to go in most cases.

You have already mentioned the inexpensive micro switch method. The switch system is quite trouble free if it is set up well from the start Usually a second series switch is used in order to positively shut off the glow when not in use.

The question of "need" for on board glow for extended idle is a moot point IMHO however . While most anyone can get a decent, reliable idle without added idle heat , the on board glow has the potential to make the best setup engines idle even lower,longer . ..but that is just a bonus .
Often over looked is a safety benefit from not having to connect the outboard glow.

Another method you already mentioned is a simple pulse width activated switch.
You could build your own but for most people the $30 to $60 units on the market work well and by the time and cost are considered ,pretty cost effective. PM me for a reccomendation and link to a very well made , local unit at a reasonable price .
A side benefit of the electronic switch is that it automatically turns off the glow when the radio is switched to "off"

Rather than a heavy 2.0 volt battery and the need for voltage drops or current limiting, the trusty old 1.2 volt NiCad can perform well and makes plenty of heat for standard 1.5 volt plugs. The 4AH capacity "D" size NiCad is usually quite adequate for very long flying sessions , provides a lot of capacity at fairly low weight and a single cell is generally more satisfactory than multiple cells in parallel. The single "D" NiCad is a very robust storage device .

[IMG][/IMG]

Here is a photo of the flight line box.


Note there is a wireless glow driver charging on the modified power panel . The power panel adds considerable versatility.
First , of course the standard plug wire setup, second the direct to plug wireless glow driver with an ammeter built in . Thirdly , the same connection that allows for charging the wireless driver can also serve to charge the on-board glow . Not often needed ,but the capability is there for those real long flying days . Also , having the charger handy there is less need for extremely large batteries as some use with their wireless glow drivers .

All of that said , I will add that only one of my planes has on board glow . It is a Saito 4 stroke powered trainer. this is a loaner/student plane and the glow was initially intended to simplify operation and provide a measure of safety . This it did very well ! The bonus of being able to idle almost forever , at very low speeds then throttle up instantly, repeatedly was just a pleasant dividend.

Not here to say "Do it my way" Just sharing a few methods that have worked for myself and others . Your needs , choices and results will of course vary .

Best wishes, feel free to PM

I want to see some more pictures of your Flight Line Box, it looks Awesome!

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Old May 28, 2012, 11:58 AM
Whatever works well .
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Hello BW ,Good to hear from you again ! Will try to post some detail photos . I did brake up a few extra "clamshell" aluminum tank halves . I can send you a pair if you have acces to a TIG or MIG welder and can handle the rest of the work . PM me for details .

BTW RE: the 2X penlight vs D cell idea , yes we have the import penlight cells here as well . They are quite cheap here too .However , there is a price paid for large capacity in inky-dinky NiCads . They are not very robust , they do not have a long life at high rates of discharge as compared to the "big boys". Generally speaking the 4.0 AH is better suited to this application . The very high quality D size, US made cells in the photo above have worked out very well. I picked a bunch up at a ham radio swap about 7 years ago . The one in my plane has been working well for 5 years now . Worth mention is that there are D size NiMH batteries rated at 10 AH but the 4AH NiCad still seem the best suited for this application from my experience and observations .
In order to increase the capacity of the penlight cells , they simply thin down the internal components . This results in far less durable cells that are not as suitable for high discharge rates in most cases.

Just my personal real world on board glow experiences here . The little intermittent ground support devices are a different application . In that application I like to use the good old 1.2AH to 1.8AH sud C NiCads . Having the ability to top off the caharge conveniently at the nearby, light weight flight box negates any need for larger capacity . Besides, with OBG I rarely have to use an outside power source for that plane.
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Old May 28, 2012, 01:12 PM
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Quote:
Originally Posted by Gary Cee View Post
Hello BW ,Good to hear from you again ! Will try to post some detail photos . I did brake up a few extra "clamshell" aluminum tank halves . I can send you a pair if you have acces to a TIG or MIG welder and can handle the rest of the work . PM me for details .

BTW RE: the 2X penlight vs D cell idea , yes we have the import penlight cells here as well . They are quite cheap here too .However , there is a price paid for large capacity in inky-dinky NiCads . They are not very robust , they do not have a long life at high rates of discharge as compared to the "big boys". Generally speaking the 4.0 AH is better suited to this application . The very high quality D size, US made cells in the photo above have worked out very well. I picked a bunch up at a ham radio swap about 7 years ago . The one in my plane has been working well for 5 years now . Worth mention is that there are D size NiMH batteries rated at 10 AH but the 4AH NiCad still seem the best suited for this application from my experience and observations .
In order to increase the capacity of the penlight cells , they simply thin down the internal components . This results in far less durable cells that are not as suitable for high discharge rates in most cases.

Just my personal real world on board glow experiences here . The little intermittent ground support devices are a different application . In that application I like to use the good old 1.2AH to 1.8AH sud C NiCads . Having the ability to top off the caharge conveniently at the nearby, light weight flight box negates any need for larger capacity . Besides, with OBG I rarely have to use an outside power source for that plane.
As normaly the engineer has to work with the facts, no fairy tales.

I did make a picture extracted form the datasheet of the supplier.
The internal average resistance is 18 mOhm for a cell, so for a 2 A the voltage drop is about 36 mV.
2 Ampere? Yes two cells parallel to glow the plug.
And for what current these cells are rated? See the drawing, 7500 mA for each cell, so 15 A two cells parallel.
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Old May 28, 2012, 01:39 PM
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And some information about the "big boys" from Power PS Sonic, the PS-D.


Gary Cee wrote:
Generally speaking the 4.0 AH is better suited to this application . The very high quality D size, US made cells in the photo.

Specs, read with me:
20 mOhm so for the same 4 A to heat the glow plug, the voltage drop is more 80 mV.
And what is the high rate discharge cutoff current????
Just as the penlite 3C? No it is 1 C and that is 4 A, no higher values are given so you have to be very carefull not make a shortcut!

I think these are outdated, at least they would be in Europe and that was the reason to find them on a swap meet.


TF
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Old May 28, 2012, 02:05 PM
Whatever works well .
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Cees
Please,try not to trash ths thread into a contest over your battery being zooperior too



Yes Cees, as I already stated , the Powersonic batteries I have been using are quite "OLD SCHOOL" ...I bought them about 7 years ago , they are still working ! That is the point . The small capacity , large package cells generally last longer.
This is for the application that is at the root of the thread On Board Glow ..not a little ground support device .Most people do quite nicely with a 1.2 AH or 1..8AH single cell for that application.

A simple, single D cell gives me enough standy glow to fly for over 4 hours as well as start the plane for a good , long flying day . One ,solitary D has been doing that for over 5 years now . No extra wiring , no problems from one weak cell going dead in the pack and pulling the remaining cells down (a coomon event with parallel connected cells . Just one battery doing a simple job.

The subject is on board glow, not your ground support using a pair of AA batteries . I have not said the AA will not deliver 2 ampere , I have said that the D cells are better suited and generally will live longer over the long run . This is based on many years of actual application .
I have given as well the reason for the longer life expectancy, not as a "fairy tale" but due largely to the actual fact that the internals are more robust when the actual AH capacity for a given case size goes down. This is what engineers call a compromise or trade-off .
Yes, your AA batteries will work at OBG but what your two AA will do for 70 minutes at a charge , the 4AH will do for over two hours per charge .Generally speaking the 4AH D cell will also do this for far more charge/discharge cycles .

Want more capacity ?
Here is the data sheet that we use to predict the operating conditions for the 10AH D cell that I mentioned above and you may have missed:

http://cellpacksolutions.com/pdf/dat...l/GP1000DH.pdf

Note that this D cell will deliver the 2 amperes for 5 full hours that your pencells strain to make for 70 minutes ! I , personally would still prefer the 4AN D cell as best suited for my needs and the extended charge discharge cycles.

That is what I offer; My real world experience with On Board Glow . From what I have seen you don't care to employ OBG so I am surprised at your interest

Comparing OBG to a small , intermittent ground support is apples to oranges in many ways . For ground support I still use the 1.2 > 1.8 AH sub C ,singly, not in parallel .In most NiCad applications a single large capacity cell is preferred over two or more small cells when wired in parallel .

The OP has been offered some suggestions along with the real world experiences behind those suggestions . The power source decision is wide as are the individual conditions that will ultimately drive the decision.
As I have understood from some of your other posts , you do not care to employ OBG anyhow .
That works too ! As I have already related OBG is not a universal need , just an individual preferrence under certain conditions or specialised needs .

Again , the subject is OBG , not ground support.

Please, lets not start a flame fest here
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Old May 28, 2012, 02:09 PM
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Gary,

To finish my comparison:

Penlite:
31,5 gram each cell so 63 gram for the 5400 mAh.

And your Big Boy with the 4000 mAh, 4000/5400 x 63 gram? So 46 gram?
No 113 gram so 35,4 mAh / gram for the Big Boy, indeed, take along your Bobcat!!

The energy weight comparison for the penlight is 5400 /63 gram = 85,71 mAh /gram, more than twice as much.

Whe you compare these data, the single penlite can do the same job, only keep the wiring short to compensate the some lower voltage.

Gary, these are facts, nothing else, that's why I show them!

TF
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