On Board glow

[tigerman]

Have a laser 80 fitted inverted run OK but thinking of fitting an On Board Glow to the model .Have been impressed by other models at our model flying site with On Board Glows fitted that are so easy to start and seem to be so reliable.What the general opinion on On Board Glow are they what they seem or are there some down side to them? Would be interested to see what the for and against are before I proceed with fitting one!

[Phil 9]

what are you hoping to gain from an on board glow?

if your engine is already running fine I would not bother

I have tried them in the past just because I like experimenting but for all the extra work installing and maintaining the system I did not feel I gained anything. The on board battery I had was small to save weight and it would always run flat before the days flying was out. in the end I found it simpler to heat the glow from an external source for starting.

Unless you have a multi cylinder engine I don't feel there is much to gain from using one if your laser is correctly set up

[Martin Harris - Moderator]

I don't know what type you used Phil, but my experience with South Herts Models intelligent glows has been quite positive. They sense the amount of support required at (from monitoring the glow filament resistance) and cut off at full throttle after a short delay. Battery endurance has never been a problem.

I know that onboard glows aren't really necessary if the engine is tuned correctly but I've found them useful on fully cowled scale models, where holes or remote glows are difficult to hide.  The glow battery weight is normally put to good use to assist with the C of G position.They also allow a little latitude on the low end mixture which can be set slightly on the rich side which I feel gives slightly better reliability in the case of something slightly restricting fuel flow for any reason.

Edited By Martin Harris on 05/11/2016 18:07:45

[Former Member]

[This posting has been removed]

[Phil 9]

I had one from just engines that (if I remember correctly) was controlled by the throttle and cut off when it moved up passed your pre-set point . it did work as described but it did not prove necessary for the sport model I had it set up on.

lasers have a high reputation for reliability and I did pose the question to the OP of what he was hoping to gain.

on board glow systems to have there place but I think it is over kill for the average club model

[Jon H]

We do not recommend the use of on board glow. All they do is add complication and weight and can mask slow run tuning errors which cause erratic or unreliable running at the point where the glow cuts out.

The only engine that I have ever used OBG on was a 5 cylinder radial that would not run without it due to not being able to adjust each cylinder's mixture individually.

If the tuning is set correctly then adding the glow will do nothing other than add weight to your model

[Martin Harris - Moderator]

Posted by Jon Harper - Laser Engines on 05/11/2016 18:01:01:

We do not recommend the use of on board glow. All they do is add complication and weight and can mask slow run tuning errors which cause erratic or unreliable running at the point where the glow cuts out.

I would add that I normally disable an on-board glow while doing any set up work.

[..]

I think there ok for convenience BUT not an answer to a poorly running engine. I've got one in a P47 Thunderbolt but plan to remove it soon.

The tuning of the engine is different to the settings on a motor started with a conventional glow starter, so all is ok until your onboard battery gets low and then you have a mistuned engine that's going to struggle to run anyway so I end up unconfident in the glow set up. It's like a bit of a vicious circle and after trials personally  I trust the well tuned motor rather than risking unknown battery capacity so it's a no from me. 

Edited By Justin K. on 05/11/2016 18:36:08

Edited By Justin K. on 05/11/2016 18:37:26

[Former Member]

[This posting has been removed]

[Bob Cotsford]

I've got them on several models with inverted or fully cowled engines. It saves reaching around under the model to fit and remove the glowclip, the latter with the engine running. I've never found battery capacity a problem with any of the brands I've tried. Currently I'm fitting HK units that will run off a multi cell pack, eg NiMh 4 cell, Life or whatever I have to hand when installing it.

[J D 8]

Second Bob's comments about safety , have fitted the type that you push a button that flashes for about 15 seconds as glow is on then turns itself off.

[David Ovenden]

I can also throughly recommend the South Herts Models unit. Works brilliantly especially in cowled scale models.

[Jon H]

Posted by Steve J on 05/11/2016 19:00:00:

My Laser has an on board glow.

I fill up the tank, I spin the engine to clear the cylinder, I flick a switch on my transmitter to turn the glow on, I spin the engine again, it starts almost immediately, I rev the engine a bit, I turn the glow off and I go fly.

Steve

This use case is fine, as the glow is only used for starting. Personally I wouldn't do it as its more weight to carry and if the on board battery runs flat you cant get it going, but that sort if thing is down to preference. The 15 second active type John mentions fall into the same camp.

Perhaps I should clarify our recommendation by saying that we do not recommend on board glow is used for anything other than starting the engine. Having the system come on at low throttle after the engine is started is not recommended.

[Phil 9]

Posted by The real Ron Truth on 05/11/2016 20:37:27:

Ive used them for years without problems. sounds like some just aren't very good at setting them up.

like who?

Mine was set up fine and worked. but I found the engine worked equally with out it. therefore I found it unnecessary for my particular model. there are better batteries available now than the one I used, but I did like to get many flights from my model in a day as trips to the field for me where restricted by work. so adding a limiting factor into the model did not suite me.

It is personal preference whether you use one or not. it depends on the type of model and style of flying you do that will dictate if it works for you.

[The real Ron Truth]

Ive run ic for years with glows but found they work best as an emergency option and not when starting etc as they could be a tad erratic and unpredictable. i got bit when i forgot i had one armed and flicked the prop.

If you need a very low tick over for landing , they are worth setting up on a flick switch rather than through the throttle which also drains the battery dead fast.

[Bob Cotsford]

I have mine on a separate channel mixed to the throttle with a switched condition so they are not armed until I set the tx switch and even then they only come on at lower throttle settings for starting - no chance of a full throttle start!

[Jon H]

If the engine will not run slow enough to land then it is set up incorrectly anyway. Most glow 4 strokes will idle at 2500rpm or less (depending on size, smaller engines idle faster). In the case of the Laser 80, 1800-2200rpm is where I would expect to see it and this will be plenty slow enough to land with.

Note also that lower nitro fuel, and particularly lower oil fuel can significantly improve idle performance. A friend recently discovered this when I finally convinced him to drop from 10% to 5% nitro on his Enya 120R 4 stroke. Both mid range and idle were smoother with the reduced nitro content.

[tigerman]

Jon was right I had the same problem but like Jon said I play about with the slow running jet and got to tickover a treat,no need for an on board glow,By the way the Top flite Texan fly a dream on the Laser 80,more than enough power I fly it around on about half throttle,it will go vertical on full power but that does not look scale so half throttle is enough for me!

[Ian Jones]

If you must have an onboard glow heater then I would suggest that only the likes of South Herts Models intelligent glows are of any real value. They only supply heat when it's actually needed, whatever the the throttle stick poisition is. I've seen it happen where a throttle activated glow heater has been fitted to an incorrectly tuned engine, too rich at the low end. The model being brought in for a landing and missed the strip so the pilot went for a go-around, moving the throtlle stick to full - thereby switching off the glow heater and succumbing to a dead stick induced by the rich mixture needing the heat that was no longer there.

 

Edited By Ian Jones on 08/11/2016 19:02:05

[Jon Laughton]

I use on board glow for inverted engines to avoid the difficulty of accessing the glow plug from below or turning the model over when running. I have found no problems with this arrangement at all

I also use a remote glow point for the same reason..

[Jon H]

Ian - i dont disagree with any of your points

Jon - in this circumstance its fine as long as it can be turned off once the engine is going. i wouldnt use one myself due to weight/complexity and because a remote glow serves the same function.

[Jon Laughton]

Jon (Harper) the versions I use are programmable to turn off at a certain point in the throttle range...easy to set up and very reliable

[Jon H]

Hi Jon

We dont recommend those for the reasons already detailed. Once the engine s running there is no need for it to be on.