Laser 180 Petrol

[bert baker]

The price will be what it will be,and what ever Laser set it at

I recently fitted a runtronic spark unit and a walbro carb to play at petrol on a laser,...the cost at today's prices for them comes to £182.00,

Couple that to the price of the engine and hey it soon gets up there,

 

Quality comes at a cost,,

 

Edited By bert baker on 03/08/2018 20:59:17

[SR 71]

Hi Jon can the needle valve be turned to the side, never owned a laser but very interested in the petrol one

[Former Member]

[This posting has been removed]

[bert baker]

Don't turn the needle asembly in the body of the carb ,, was what the advise always used to be,, don't think it has changed

Edited By bert baker on 03/08/2018 21:48:51

Edited By bert baker on 03/08/2018 21:49:25

[Ron Gray]

Posted by bert baker on 03/08/2018 20:58:03:

Quality comes at a cost,,

Well said that man!

[Jon H]

Posted by Percy Verance on 03/08/2018 21:31:36:

You'll find it doesn't matter where the needle is on a Laser SR, you'll never need to touch it again once it's adjusted. And that was the glow versions. With petrol you certainly won't need to adjust it.

In all the years I ran my Laser 100's, I think I adjusted the needles twice. And I bought my first on in 1993.

I recommend that all engines have their tune checked for every flying session. Its not always necessary but I recommend it none the less.

As for the petrol, its less likely to hold tune than a glow as the whole thing (petrol that is) is just more sensitive. It is a pretty easy job though as the needle is either right or wrong. There is no fuzzy area at all which makes it easy to set. Just make sure the engine is warmed up when you do it.

Again, its all in the instructions...

[Gordon Whitehead 1]

Posted by SR 71 on 03/08/2018 21:08:08:

Hi Jon can the needle valve be turned to the side, never owned a laser but very interested in the petrol one

If you mean can the carb assembly be rotated so that the needle points out sideways wrt the cylinder, as on the Saito 180 FS and ASP 180 FS, it's possible that the throttle arm/slow running screw assembly will interfere with the silencer to prevent a full 90deg rotation. If a flex tube exhaust is used, then in the absence of the silencer body I suspect that the carb assy will readily achieve the full 90deg rotation.

Anyone with a spare Laser laying around could check that for you. Mine is in a cowled installation so I can't help you with that.

Gordon

[Ron Gray]

 

I’ve been lucky enough to have got a pre-production Laser 180 gasser, or to be more precise a GA30, and have fitted to my Great Planes Giant Super Sportster ousting the NGH38 that had been in there. So far I have only ground run it twice and am planning on taking up the field for air testing tomorrow.

I thought that these 2, uncut (!) vids may be of interest but also my observations/findings on the installation and first time running.

The instructions provided by Jon are excellent and cover not only the engine settings but also the plumbing required, which must be followed for successfull running. The engine requires a 3 line system but not the usual setup as the normal fill line is used as a return as well as the fill, Jon provides a 3 way connector for this but I used the fill valve that was already installed in the ‘plane and as mine was a 2 pipe system I added the 3rd pipe to the tank. Sounds complicated but Jon provides a nice clear diagram showing how to do the plumbing.

The instructions go to great lengths to explain how important it is to ensure that there are no air bubbles in the feed line and you will see how this effects the starting of the engine in the second video. To ensure air is removed, the carb needs to be well primed and this is made easier if you use an electric starter. If you’re used to Walbro type carbs on other gassers then the method for cold starting a Laser is subtly different, especially so with mine as it hasn’t yet been fitted with a choke plate! Anyway, after priming to remove air bubbles, it’s a few flicks with throttle open choke closed (finger in my case), ignition off of course, then a few flicks with throttle closed, ignition on then flick to start. You can see from my videos that the engine ran then stopped and this was due to air in the system also you can see that I also over primed the engine and it took a few flicks to fire it up. All of this is a learning curve for this engine! The other thing to mention is that, as per the instructions, the needle adjustments are very, very sensitive. Again, looking at the second video you will see that when I adjusted the top end I turned it too much and the engine died, but after restarting I didn’t make the same mistake and got it running WOT at 8.6K turningba 17x8 wooden prop, not too shabby! The transition from low to high was immediate with no hesitation so the low needle was left alone, so she is now ready for flight!

Bearing in mind that this is a pre-production version it’s absolutely brilliant, runs and sounds awesome. Assuming that the flying goes well tomorrow, Laser have a winner on their hands.

Vids

https://youtu.be/bNEVHUxDxwE

Edited By Ron Gray on 13/08/2018 15:40:30

Edited By Ron Gray on 13/08/2018 15:45:51

[Ron Gray]

Here's the second video, couldn't embed it in previous post as can only copy the URL when using a mobile device to upload!

[Jon H]

Nice one Ron. One thing you might want to play with at some point is spark advance as its set for aspen and you may, or may not, find improvement. There is not much scope to move it but feel free to play through the range available and see if there is any sort of difference

[Ron Gray]

Ah, didn’t think of that. Maybe I should get some Aspen first to see what, if any, difference it makes, mind you, I don’t mind the smell of petrol, actually quite like it!🤪

[Jon H]

Posted by Ron Gray on 13/08/2018 18:16:17:

Ah, didn’t think of that. Maybe I should get some Aspen first to see what, if any, difference it makes, mind you, I don’t mind the smell of petrol, actually quite like it!🤪

just use your normal choice of fuel. no need to get crazy

[Piers Bowlan]

Jon, have you done any testing regarding the GA30 noise levels when turning the 17X8 wood prop? I just wondered if it was any noisier, or no different to, the Laser 180 glow?

[Ron Gray]

It was one of the things I was going to do today as I’m flying my 180 glow powered Hurricane as well as the Sportster so will be able to compare the in flight noise difference.

[Jon H]

Posted by Piers Bowlan on 14/08/2018 06:44:20:

Jon, have you done any testing regarding the GA30 noise levels when turning the 17X8 wood prop? I just wondered if it was any noisier, or no different to, the Laser 180 glow?

I have not tested anything. There are too many variables for me to get any useful information on noise and we also lack the required equipment.

In flight though the 155 in my pulse and 180 in my stampe are certainly no louder than their glow counterparts. I would say that off throttle the petrols are quieter than the glow used to be, while flat out they have a little more crackle in the exhaust note but its still not loud. When flying as wings and wheels the engines were barely audible over background noise.

[Ron Gray]

I would agree with Jon, in fact several of my flying buddies with me at Wings and Wheels were really impressed with how quiet the engines were in comparison with everything else flying at the same time.

[Piers Bowlan]

Thanks Ron & Jon, that is encouraging news. The best news would be info on when the first production engines will become available. I have an NGH 38 that was destined for my World Models Pa 25. I would much rather fit the Laser GA30 but with other projects on the go the Pawnee can wait until next year for it's engine, no problem.

[Ron Gray]

Having spent the day in flight testing the GA30 I can assure you that it is more powerful, quieter, cleaner and easier to start than the NGH38 (the engine the GA30 replaced in my Giant Sportster! Here is an update of the day’s events.

I planned to fly the Sportster back to back with my Y T Hurricane as that is powred by a Laser 180 although it is a bit smaller and lighter airframe. This would give me a good comparison of power, noise etc.

So first flight. I carried out the same priming and choking that I had done in the videos shown above but I had far more problems getting it to run due to air in the line (I need to investigate why this is happening as I have ‘correct’ plumbing and a good felt clunk in place). In the end I reverted to the electric starter and that got over the problem, subsequent starts were by hand and there were no further air issues. Take off and climb out were very rapid and took me a bit by surprise, the overall speed of the Sportster was far in excess of that previously experienced. However, it soon became apparent that the prop was undersized for the airframe as not only was it too fast it was also quite noisy. The first flight lasted about 8 minutes. Next up was the Harry Kane and immediately it was noticeably quieter in both volume and ‘softness’, it was also slower than the Sportster.

No adjustments were made for the second flight but after about a couple of minutes into the flight the engine starting running a bit rougher than the first flight. I continued for another couple of circuits then landed and without stopping the engine ran it to full throttle, which was fine, then set about adjusting the slow running needle. Now here I had a problem, I adjusted the needle to make sure that the transition from low to high was smooth but did find it difficult to notice any difference irrespective of the amount of turning of the needle. I double checked the top endvagain and took off. The engine was still running fairly rough, especially in the mid range and I had now lost the edge to the top end. Landed and went through the sequence again and still not much change in the air but on the ground it was spot on. Anyway, this sequence of events went on for another 3 flights. I then changed my approach and with the engine running at about 4K adjusted the low end needle. Now I was able to see a difference in the mid range running. Having flown the Harry Kane for a couple more flights I decided to try it’s prop, an 18x8, on the GA30.

The next flight showed me that the change in prop was a move in the right direction as the noise was substantially reduced plus the Sportster flew much slower but was still able to pull big loops and aeros. I still need to slightly tweak the running but an 18” prop is the smallest I will use for this engine / plane combination.

So, in summing up my findings:

For the first start of the day, use an electric starter to ensure that all air is drawn through the pipeline.

Be very careful when adjusting the top end needle, it is very sensitive.

Adjust the low end needle with the engine running at mid revs.

Be aware that it is a noisier engine than the glow equivalent but maybe an exhaust extension could help this.

Get used to a lack of muck getting thrown out of engine!

[Former Member]

[This posting has been removed]

[Jon H]

Thanks for the update Ron.

The only part that really surprises me is the noise issue. I had not found the engine to be nosier but the note is different for sure. At high power there is a sharper crackle but at part throttle I find the note much softer. Clearly airframe and so on makes a difference here.

I tend to electric start my engines as, frankly, its just quicker. I do usually hand start the stampe as its set up perfectly now and its not an issue, but everything else I leccy start as they are usually buried in cowls anyway.

With the tuning side, it is more or less impossible to set the tuning 100% on the ground. Its really a case of flying it and seeing how it performs, then making a small adjustment. You can get it close on the ground, but its never going to be perfect. The main needle is very sensitive and I find that actually makes the engine easier to set up as its either right or wrong with little grey area to get lost in. That said, I have never tried the 4000rpm approach as i always tuned in the air so this could be an easier method for ground tuning. If others have the same trouble I will recommend they try it and see what happens. Its tidbits like this that are really helpful to me as I can revise the instructions.

I will also send you another regulator Ron as I have been experimenting further with the spring pressure. Give that one a try and let me know if its better/worse/indifferent. You can also use it as a no return valve in the feed line if you like but I have not found I have needed it on any of my test engines so far so I would use that as a last resort. I will try and get you a proper choke plate as well so you can give it a priming spin with the starter.

[Ron Gray]

As you point out Jon, airframe can make a difference and I do know that the Giant Sportster is a noisy airframe due to its large wing areas which are open construction, ditto the fuz. This is the third engine to be run in this airframe and all have been noisy but to be fair, the GA30 is the least noisy! what would be interesting would be to replace the 180 glow in the Harry Kane with the GA30 and see what that is like!

Tuning on the ground can only get you so far so it is a question of tweak / fly, tweak / fly and repeat until correct then leave alone and you are so right about the main jet, you get it wrong and the engine stops!

On the starting front, it was very satisfying to just simply flick it over once (no back flip necessary) and for the engine to burst into life (obviously after the leech start). So much so that a few of my flying mates commented that they wished theirs (gassers and glow) started as easily.

[bert baker]

Oh if only I could get one

[Former Member]

[This posting has been removed]

[Ron Gray]

Today I will be mostly flying the Giant Sportster with the GA30!

Last time at the field I had the devil’s own job to get the engine to run correctly, it just wouldn’t rev past a fast idle, so I gave up and flew other models. Last weekend I de died to have a look at what the problem was and with lots of help from Jon we were able to ascertain that it was air in the system causing the problem. Jon came up with the suggestion of using my filler pump to suck the air from the system by attaching it to the carb feed pipe and this really worked well, there was a lot of air trapped in the GA30’s pump. Having got rid of that the engine started and ran without cutting out but because I had previously altered the low end needle (to try to get over the running problems) I then needed to alter that too, by about 2 turns!!!. The engine is now running correctly so back up to field today and I will do another report tonight.

One thing about these problems is that I have got to know the engine and it’s ‘requirements’ and as stated in a previous post it is not the same as a Walbro equipped gasser. The other thing is that most of my problems are a tually covered in the instructions that come with the engine, my only criticism being that some of the answers are a bit ‘hidden’ and one thing that should be made a lot clearer is, do not dick around with the low end needle until you have had some flying as ground tuning is only very rough tuning. The other thing is that air in the system is a killer and it must be purged from the system before any other adjustments are made.

Anyway I’m not late for flying so will close this and return later!

PS still in love with the GA30!

[Jon H]

Following the back and forward with Ron trying to sort out his issue I will be rearranging and re writing some of the section in the instruction. Part of the point of this beta test is to give the instructions a test drive and as they have been found to be not 100% clear I will be making some changes.

I also suspect that Ron has been suffering due to the lack of the proper choke that will come with the engine. I will be sending this too him asap.

Air bubbles are the engines arch nemesis and clearing the fuel system of air before starting is very important.