Laser Engines - Technical questions

[Nick Somerville]

I have read a variety of solutions on here regarding lighting the glow plugs on a Laser V twin. I am not electronically minded but wonder about the benefits of an on board system. I don’t use a panel indicator for my current laser glow engines and simply use a glow stick via a remote connector. So I could stay simple and just buy another glow stick and fit two remote glows connections  at the bottom just behind the cowl of my Sea Fury.  Will just need to remember to remove both after start up. On the other hand the space behind the cowl is very tight so if there us a simple on board option it could be worth considering. Thoughts welcome please.

[Ron Gray]

For my Laser twins I have a remote connector which is connected to both plugs, using my RCATS glow driver I can light both plugs. The only change from this is with the in-line twins which, don't like that setup due to them being anodised, so I use 2 remote connectors and 2 drivers.

[ASH.]

Nick, look out for an SH (South Herts) twin intelligent onboard glow..

 

Both plugs will stay lit so no chance of flameout..  Plus, it only comes on when it detects low plug voltage ie. when cold fuel comes in on an aboarded landing.

Edited August 7, 2021 by ASH.

[Frank Skilbeck]

Ron, the other thing you could try is to power both plugs in series with a 3v battery, that way you would avoid the insulating anodising as I assume the threads in the cylinder head are not anodised. I power the plugs on my V Twin this way with 2 subC cells in series. 

[Nick Somerville]

45 minutes ago, Ron Gray said:

For my Laser twins I have a remote connector which is connected to both plugs, using my RCATS glow driver I can light both plugs. The only change from this is with the in-line twins which, don't like that setup due to them being anodised, so I use 2 remote connectors and 2 drivers.

Looked up RCATS driver and couldn’t find a supplier in the UK. They do look like a good solution though especially as they automatically adjust for the twin plugs. Where was yours from Ron?

[Ron Gray]

58 minutes ago, ASH. said:

Nick, look out for an SH (South Herts) twin intelligent onboard glow..

 

Both plugs will stay lit so no chance of flameout..  Plus, it only comes on when it detects low plug voltage ie. when cold fuel comes in on an aboarded landing.

As Jon would say, a correctly setup and tuned engine doesn’t need onboard glow drivers!

 

51 minutes ago, Frank Skilbeck said:

Ron, the other thing you could try is to power both plugs in series with a 3v battery, that way you would avoid the insulating anodising as I assume the threads in the cylinder head are not anodised. I power the plugs on my V Twin this way with 2 subC cells in series. 

As my 200 in-line is in a ‘test mule’ I didn’t worry about having 2 separate connections but will get over the anodising issue when I fit the 160 in-line in the Mustang. 
 

18 minutes ago, Nick Somerville said:

Looked up RCATS driver and couldn’t find a supplier in the UK. They do look like a good solution though especially as they automatically adjust for the twin plugs. Where was yours from Ron?

Directly from the ‘states Nick, expensive but worth it!

[Steve Dunne]

Excellent glow drivers - charge once a year, use every day.

https://www.rcatsystems.com/rc.php

 

Steve.

[Jon H]

If you use on board glow (not recommended) make sure you can turn the blasted thing off. Trying to tune the engine with OBG getting in the way is impossible and more often than not the glow drivers themselves cause more problems than they avoid. 

 

You dont need a glow driver for reliable running. If a cylinder is cutting out then it is either incorrectly tuned or the carbs are not operating together. IN either case it is very easy to rectify. None of my own engines have on board glow and on the 4 occasions i have lost a cylinder it was always a fuel flow problem. I either ran out, had a blockage in the needle, or a split clunk line or similar issue. I have never had one just give up for no reason. 

 

For starting i use a 2.4v battery (a 2v lead acid would probably do) and i put the +ve lead on one plug, and the -ve lead on the other plug so they run in series using the engine to complete the circuit. I do the same with the 4 plugs on my OS Pegasus with them wired 2 in series 2 in parallel. I then run these wires to points on a cowl or similar where two croc leads can grab them.

 

Honestly, just keep things simple. Less junk onboard means less to go wrong and less dead weight to carry. It takes less than 5 minutes to set the slow running needles and once set the only reasons for cylinders dropping are ones a glow driver cannot solve. Even if a cylinder does drop out throttle back to about 80% of full power and just ignore it. The engine will run on the remaining cylinder and the model will keep flying. On my P39 (80 inch, 21lbs, 20x10 prop 300v) i lost a cylinder due to debris ingestion just as i left the ground. Landing ahead was not an option due to a large hedge, but throttling back as described and climbing as gently as i could (straight line, no turns for 20-30 seconds) before leveling off (gain speed another 5 seconds) and starting a gentle descending turn had the problem solved. 

 

The thing that saved my bacon was i already decided what to do if i lost a cylinder about 2 years before so all i had to do was enact my plan. 

 

 

[Martin McIntosh]

I have a couple of the SH twin glow drivers kicking around somewhere, ex Lanc. May wish to use one of them myself for my latest project if only I could get my hands on a 300V.

[Jon H]

whats the new project martin? anything exciting?

[Manish Chandrayan]

Should  we expect to ever again see a 300/360 v in stock please? 

[Martin McIntosh]

The 77" SF Jon.

[Jon H]

At 77 you might get away with a 200, depending on how heavy it is. I guess its a plan build? Do you know the weight?

[Martin McIntosh]

From the specs. it looks like a 200 will only turn an 18x8 at about the same revs as a 180 so at nearly twice the price would not be worth it.

I have not been able to get an estimated AUW or any other information about the plan so I am in the dark here other than Black Horse quote an optimistic 15lbs for theirs.

[Jon H]

200v's are a good bit quicker than a 180. Somewhere in the order of 300rpm normally. Admittedly that is a smaller amount of extra power than the price difference might suggest but a 300 is a great deal more and would likely be a touch excessive unless you were up at 20lbs. My P39 is 80 inches, 21lbs and is got loads of power with a 300. The fury is 23lbs i think and well powered by a 360. 

 

i would say 15lbs is a little imaginative. 17 or 18 would be my bet. If so a 200 would be more than man enough for the job. 

[Martin McIntosh]

As you know I can build light and have gone to a lot of trouble selecting wood, retracts etc of the lightest available type and I shall be getting rid of nearly all the ply in the construction because it is old fashioned and generally a waste of time. I was wondering about a 300 in case this does not work out well, but they still appear to be way distant regarding availability anyway.

The plan suggests a 120 or a 25cc two stroke depending on which part you look at, and considering how much unneeded clobber there is on the original I am hoping to get it very light.

[Tomtom39]

On 17/08/2021 at 08:11, Manish Chandrayan said:

Should  we expect to ever again see a 300/360 v in stock please? 

Jon. Are you going to building anymore v300 or 360's?

[Jon H]

Gents, i will not be answering any stock/production related questions so please stop asking. This thread is for technical questions. 

Edited August 19, 2021 by Jon - Laser Engines

[Tomtom39]

2 hours ago, Jon - Laser Engines said:

Gents, i will not be answering any stock/production related questions so please stop asking. This thread is for technical questions. 

?

[Manfred Straucher]

Hello,
I have a 1/4 scale Fokker D.VII kit from Balsa USA here and a Laser 180 and a 240V sitting on the shelf. Which of the two would be better suited for the Fokker? The manufacturer states a 180 four stroke as a possible engine for a weight of 18 - 20 lbs. Searching internet forums, I see that most are putting in a Zenoah G38, and the Fokker usually weighs between 23 and 25 lbs. My question now is if the Laser180 is still suitable at this weight, or if I would be better off installing the 240V. Is the 240V even suitable for a slow flying biplane?

Manni

[David Davis]

Welcome to the forum Manfred.

 

I'm sure that Jonathan Harper of Laser Engines will be along in a while and will give you the correct advice but for what it's worth, I have an un-built DB Sport & Scale SE5 kit which is also 1/4 scale. The SE5 was a little smaller than the Fokker D.VII having a wingspan of 8.1 metres as opposed to 8.7 metres for the DVII. Jonathan recommends the Laser 180 as the best engine for the SE5, so I expect that the 180 should suit the DVII too.

[Jon H]

Manni

 

DD has set it out well. 

 

I would be very wary of builds on internet forums, especially if those builds are in the USA. Most US modellers build a great deal heavier than we do here in Europe and often their choice of powerplant is as much to blame as anything else. 

 

As you say, the model is expected to weight 18-20lbs according to the manufacturer and that should be quite easy to achieve in my view. At this weight either engine will offer excellent performance but i suspect the 180 is going to be happier on a large prop than the 240v. I cant actually remember ever testing a 240v on a 20x6, but i can give one a try if you like? 

 

In any case, there are no wrong answers here and either engine would do the job. We normally recommend the 240 for faster flying models than this but as you already have it there is no harm in using it if you want to. If the model did end up at 23lbs it would still fly with the 180 even if climb performance was a little sluggish.

[Frank Skilbeck]

Manni, my Mick Reeves 1/4 scale camel flies on a 200v, has flown on a 20x6 and now a 19x6, enjoy the DVII, I have had a couple of smaller ones (Flair one flying on an old Laser 61) and they all flew lovely.

[Dirk Witvrouwen 1]

On 19/08/2021 at 14:24, Manfred Straucher said:

Hello,
I have a 1/4 scale Fokker D.VII kit from Balsa USA here and a Laser 180 and a 240V sitting on the shelf. Which of the two would be better suited for the Fokker? The manufacturer states a 180 four stroke as a possible engine for a weight of 18 - 20 lbs. Searching internet forums, I see that most are putting in a Zenoah G38, and the Fokker usually weighs between 23 and 25 lbs. My question now is if the Laser180 is still suitable at this weight, or if I would be better off installing the 240V. Is the 240V even suitable for a slow flying biplane?

Manni

 

Once flying, don't forget to let us know how the Laser180 (or V Laser) fairs in the BUSA DVII. Always good to have flying references with feedback.

[Artto Ilmanen]

I finally got the carbs of my 300v in sync again

 

(thanks Jon and Ron ?)

 

As I do not have the cowl on I think it's time to check the valve clearance.  Unfortunately, I have forgotten how to do it: was it 0,05mm-0,1mm? And a cold engine? The piston at TDC after the intake valve closes?