[Laser 180 Petrol]

Posted by Jon Harper on 03/11/2014 11:33:17:

The engine is the same as the glow version mechanically, although a great many other things have been tested (cam timing, comp ratio etc etc) to see if any improvements could be found. This example is running slightly different valve timing to a standard 180 but the performance difference between the two is negligible.

the last flight I did included a bit of a stress test for the big end bearing and engine as a whole. Long story short, I left it at full throttle for a solid 10 minutes before getting bored of the fact that nothing was going wrong and so went back to flying more normally. This mirrored a 5 minute test I did on the bench which showed a heat build up and slight loss of performance after about 2 or 3 minutes flat out on the ground, the engine did continue to run though but lost about 300rpm by the end of the 5 minute test. The purpose of repeating the test was to see if the same problem existed in flight with proper cooling and even at double the duration the engine was perfectly happy so cooling is not an issue.

Hi Jon

Thanks for the update. It's very encouraging the big end bearing holds up well. It's very obvious that when running on petrol a special attention to cooling arrangement is needed no matter what make the engine is. I recall having read an article written by Pe Reivers on MVVS engine temperatures. The point of the article was that if no ducting / baffles are used a petrol engine is sure to overheat.

Also, from what I have read on petrol Saitos (FG-57TS, FG84R3, etc) the general consensus seems to be the baffling is of outmost importance to control operating temperatures.

Good luck with R&D and please be assured that there will be buyers of Laser petrol engines (myself included) once you feel ready to launch one.

I would love to see a Laser 310V / Laser 360V petrol. Maybe if you can sort out the challenges related to a compact & well performing carb small enough, then, a petrol V-twin could be developped. I guess the current line of V-twins feature the same big end bearing as the 180 single?

Further, both CH Ignitions & RCEXL have their versions for un-even twins. I think the lates Saito's use the RCEXL (rebadged to Saito).

-Artto

[Laser 180 Petrol]

Posted by Jon Harper on 10/10/2014 12:42:08:

All the details I have so far are:

29cc capacity

Bronze bush big end

40:1 fuel mix

prototype running on walbro/tillotson carb but more development is to come as its not suitable for a model.

Fuel consumption approx. 12cc/minute when flying normally with 17x8 prop.

Props in the 17-22inch range

I have no details of running time (hours) but the engine has been run like this for over a year of testing without any mechanical distress.

So the prototype engine is mechanically the same as the glow version? i.e. you have just installed a different carb arrangement and the CDI?

Btw. I'm looking forward to seeing a flying video!

-Artto

[Laser 180 Petrol]

Posted by Jon Harper on 12/10/2014 10:44:22:

Cautiously I would hope for first 1/4 of 2015 as the engine needs to be tested in the winter to see how it handles the cold and snow.

I happen to know one person that might be a compenent official Laser destructer tester..including winter tests in cold and snow

 

Seriously, this is an interesting thread!

-Artto

 

 

Edited By Artto Ilmanen on 02/11/2014 10:46:40

[Petrol 4-strokes]

Hi folks

Some one told me Laser Engines have been testing the engines running them on petrol. If I have the correct understading the current range of Laser engines (at least most of them) are mechanically suitable for petrol. The power output is said to be similar to glow but the transition is inferior due to lack of suitable carburettors. Even the walbro type carburettors are said to be not up to the task.

So let's hope Laser engines continue the testing to find or develop a suitable carburettor for petrol. I personally like the idea of odourless Aspen fuel, easy to get + economical. The pump feature of the petrol carburettor is nice too. It makes installation of the tanks very straightforward without need to think about tank height or distance, etc. The spark ignition, while being more complex vs. glow plug, has the advantage of maintaining the ignition timing always the same regardless athmospherical changes. So all these matters taken in consideration I would be very happy to invest in a Laser petrol engine while being happy with their marvellous glow engines, too.

one more thing: with the rise of EFI (see Evolution 62GXi EFI) I would be very happy to see EFI petrol versions of Laser engines..

[Sea Fury FB11 Build]

Posted by Glyn R on 11/06/2014 15:09:09:
The op topic is getting lost. Can anyone help with forward folding rear U/C.

Glyn R

You are right, sorry. Please admin can you move my posts on Laser engine to the correct sub forum?

-Artto

[Sea Fury FB11 Build]

Posted by Artto Ilmanen on 11/06/2014 07:20:37:

Posted by Jon Harper on 06/06/2014 10:09:37:

If there was a 4 stroke petrol available that was not crazy money and would run reliably on that non stinky aspen fuel then for sure I would be up for it, but sadly, no such beast exists

As for the fury, how heavy are you expecting? I have heard reports of the YT up at 25lbs

Some one told me Laser Engines have been testing the engines running them on petrol. If I have the correct understading the current range of Laser engines (at least most of them) are mechanically suitable for petrol. The power output is said to be similar to glow but the transition is inferior due to lack of suitable carburettors. Even the walbro type carburettors are said to be not up to the task.

So let's hope Laser engines continue the testing to find or develop a suitable carburettor for petrol. I personally like the idea of odourless Aspen fuel, easy to get + economical. The pump feature of the petrol carburettor is nice too. It makes installation of the tanks very straightforward without need to think about tank height or distance, etc. The spark ignition, while being more complex vs. glow plug, has the advantage of maintaining the ignition timing always the same regardless athmospherical changes. So all these matters taken in consideration I would be very happy to invest in a Laser petrol engine while being happy with their marvellous glow engines, too.

p.s. Glyn R, I take the liberty to mention that the twin carb is not complicated to operate. Even I who is not an expert by any means can do it properly, thanks to the great service / instructions of Laser engines.

-Artto

one more thing: with the rise of EFI (see Evolution 62GXi EFI) I would be very happy to see EFI petrol versions of Laser engines..

[Sea Fury FB11 Build]

Posted by Jon Harper on 06/06/2014 10:09:37:

If there was a 4 stroke petrol available that was not crazy money and would run reliably on that non stinky aspen fuel then for sure I would be up for it, but sadly, no such beast exists

As for the fury, how heavy are you expecting? I have heard reports of the YT up at 25lbs

Some one told me Laser Engines have been testing the engines running them on petrol. If I have the correct understading the current range of Laser engines (at least most of them) are mechanically suitable for petrol. The power output is said to be similar to glow but the transition is inferior due to lack of suitable carburettors. Even the walbro type carburettors are said to be not up to the task.

So let's hope Laser engines continue the testing to find or develop a suitable carburettor for petrol. I personally like the idea of odourless Aspen fuel, easy to get + economical. The pump feature of the petrol carburettor is nice too. It makes installation of the tanks very straightforward without need to think about tank height or distance, etc. The spark ignition, while being more complex vs. glow plug, has the advantage of maintaining the ignition timing always the same regardless athmospherical changes. So all these matters taken in consideration I would be very happy to invest in a Laser petrol engine while being happy with their marvellous glow engines, too.

p.s. Glyn R, I take the liberty to mention that the twin carb is not complicated to operate. Even I who is not an expert by any means can do it properly, thanks to the great service / instructions of Laser engines.

-Artto

[Laser Tank Position]

Hi Kev, I would say not a problem, I have a T28 with the carb about 25mm above tank and a spitfire with carb about 40mm below tank and a typhoon with carb about 70mm below tank.>>

All laser’s and no problem with the running of any of them, that’s another good thing about laser engines.>>

Steve >>

 

Hi Steve

 

I'v been running my Laser 240v with the Cline regulators but as I tested the engine without them, out of curiosity, I noticed it runs smoother without the Clines. So I'm converting my tank set-up and fly the model without the Clines.

In my case (a GP Yak 54) the carbs are about 50mm below the tank centerline as the engine is inverted.

 

How do you adjust the carb in the Typhoon? I'm just thinking that if you adjust it to max power on the ground what happens when you fly inverted or vertical? Won't it go lean?

 

(I'm thinking that if I mounted my engine cylinders cylinders pointing up the adjustement of the carbs might be less fussy as when you adjust them to max power on the ground the engine would go rich due to the hydrostatic pressure change (if the tuning changes at all) when flying inverted. This is safer with respect of avoiding dead stick etc. )

 

I appreciate any comment

 

Edited By Artto Ilmanen on 06/07/2013 14:52:48

Edited By Artto Ilmanen on 06/07/2013 14:54:28

[Laser Tank Position]

Posted by Percy Verance on 11/03/2013 13:21:52:

Hi Artto

The Perry VP20 has adjustable flow, using the large nut on the end, as do the other Perry pumps. I guess that in an installation such as Graham's, the facility to regulate the fuel flow rather than pump it would be of greater importance?

Just as a point of interest, do take your pressure feed form your silencers or the crankcase?

Hi Percy

I take the pressure feed from the silencers, see my reply #66 in this thread for the pctures:

http://www.rcmf.co.uk/4um/index.php/topic,87565.40.html

Rgds Artto

P.S. i got the hint to use the Clines in one conversation with Neil Tidey..

[Laser Tank Position]

Posted by Percy Verance on 10/03/2013 18:50:03:

Hi again Graham

With regard to Artto's suggestion. Using the Cline system would also be an excellent solution. However, Artto is using his Laser V twin, and that is probably why he's choosing to use the Cline regulator. The V twin is too smooth to produce the vibes required to operate a regulator such as the Perry VP20. In fact the info supplied with the VP20 specifically state it will be unsuitable for use with twin cylinder engines.

Edited By Percy Verance on 10/03/2013 18:52:36

Edited By Percy Verance on 10/03/2013 18:56:58

Hi Percy

Based on some other discussion in this site I was under the understanding the Perry VP-20 does not feature a regulator? I tried to check this in the Perry web site but I couldn't find any usefull info on the matter. However, you say you have been using the VP-20 so how's the thing is there a regulator in the VP-20 or not? (In your post you do refer to "..oscillating pump/regulator.."

thanks, Artto

[Laser Tank Position]

Posted by Graham Cramp on 08/03/2013 04:34:04:

Hi all,

I've just bought a Laser 100 to fit into a Topflite P47, I've just offered it up to the fuselage and without any accurate measurements it looks like the carb will end up around 60mm below the tank centre line... Looks like some serious work to get the tank any lower because the wing will be in the way - does anyone think this will be a serious problem? Or does anyone have any ideas to line them up better?

Thanks

Graham

 

Hello Graham

(in case you notice a problem caused by the tank height after having actually flown the model)

You might want to try the Cline regulator system to cure the tank height problem. I'm using them in conjunction with my Laser 240v.

The Cline system is a demand-type regulator that gives the carb the amound of fuel the carb wants. So there isn't any fuel pressure against the HS needle. Further, the hydrostatic pressure remains the same in all circumstances.

I got mine from:

http://www.billsroom.com/pcfs/

Regards Artto

 

 

 

 

Edited By Artto Ilmanen on 08/03/2013 06:43:12

[Laser Tank Position]

Hi Steve,

 

I called Neil at Laser engines. He wasn't too concerned about the height of the tanks but he said the tanks mounted 150mm away from the carbs would never work. He recommended carrying out needed modifications to get the tanks closer to the carbs, less than 60mm or so. Alternatively a use of pump such as cline might be another solution.

 

Any experiences on the cline system / Perry pump with Laser engines?

 

Btw Neil was of great help and a very nice person!

 

artto

[Laser Tank Position]

Hi Steve and John

 

Thanks for your help I guess I will test the set up; let's see then! I will post my experiences once something to report

 

regards artto

[Laser Tank Position]

Hello Steve and others;

 

I'm mounting a Laser 240 twin in a Great Planes YAk 54;

 

It seems the tanks c/l will be about 50mm higher than the carbs centerline which should be ok, based on the posts above.

 

However, how far can the tanks be from the carbs? I know the general principle is "as closed as possible" The challenge is: the tanks won't fit (without modifications) inside the engine box = this means a 15 centimetres or so distance to the carbs from where the tanks meet the bulkhead .

 

Is this way too too far or worth trying and testing? I know Lasers draw fuel very well but I am lacking "a rule of thumb" on how well Lasers draw fuel when the nose is pointing up..

 

Any hints / comments from more experienced laser owners are wellcome and appreciated!!

 

thanks, artto

[Zlin 50]

Stephen and Lee,

 

Thanks for the help! Nice to know someone else has followed the same path..

 

Btw I just realized RCU has published a review on the Zlin I haven't read it through yet, though..

 

Mine is now ready for maiden with a Saito FA-125. I'm using a spinner bolt which weighs 28 grams instead of a heavier aluminium spinner. I also mounted a home-made flex muffler which is pretty light. (Fortunately we don't have very strict noice regulations) So I had to add about 50grams of lead on the nose.

 

I will try a 16x6 APC prop first I would like a 3-blade one, though. Let's hope the weather stays mild and calm so I can maiden the model soon. (I'm loving in Finland so let's cross fingers..)

 

rgds Artto

[Zlin 50]

Hello all

 

I'm reading the manual on the page 19:" Wing Assembly"

 

4) "to help strengthen the wing tube, use machine screw M3x2,5mm to secure and lock the wing tube at the end of wing tube as position already market and predrilled.."

 

??? I had a look inside the wing and it seems a screw 2,5mm long can never reach the wing tube and lock it..(?) Is there something I don't understand now.. ?? Besides, I must have lost the associated screws somewhere..

 

Anyways, can I just forget about securing the wing tube this would make transportation of the model easier, too? Or shall I risk loosing the model if doing so..any ideas from more experienced modelers?

 

thanks artto

[Zlin 50]

Hi Lee

 

No, I don't have any experience in checking the side thrust in flight..Is there some special procedure to do it? I am happy to hear any hints..

 

thanks mate

[Zlin 50]

Posted by Lee Smalley on 03/08/2011 16:09:13:

Hi Artto, firstly i ignore the fixing locations as suggested by the kit, i mark the centerline of the firewall vertically and horizontally, then i mount the engine on the mount making sure the prop driver is the prescribed distance from the firewall, then i (with the cowling roughly fitted line up the engine with the centerlines marked and the center of the cowl exit, its a tough thing to get right first time!!

Hi Lee,

 

Thanks for the hint I guess I can act accordingly next time. In this case it's too late, I'm afraid. I used the kit instructions and drilled the bolt holes accordingly, etc.

 

So maybe all I can do is add a tiny amount of side thrust to help the prop exit more centrally and rotate the cowling just a little, if necessary.

 

artto

[Zlin 50]

Posted by Lee Smalley on 03/08/2011 14:17:25:
Hi Stephen eventually people find out the rudder is one of the most important surfaces of them all, try this it might help.
Get a quiet day with no one around and just racy around do dummy take of runs with much lower power, up and down the strip and do it continuously for a full tank, this will get you really used to the rudder effect and how the model reacts on the ground practice just squeezing the rudder to hold a straight line down the strip, as for engine alignment if you are putting some right thrust in the engine then you have to offset the engine to the left on the firewall so that the prop exits centrally I fitted mine with no additional side thrust and had no problems

Hi Lee,

 

Thanks for your reply so in your model the prop exits centrally without any modifications when using the original engine mounts? This is confusing as this is what I'm doing yet the prop doesn't exit centrally...

 

Or, did you twist or turn the cowling to make the prop exit centrally?

(sorry if this sounds insisting just want to make it clear for myself..)

 

artto

 

 

 

[Zlin 50]

Lee and Stephen,

 

 

How did the cowling fitted in your models? In my case the engine sits to the right off centre in the extent the spinner won't sit in the centre of the cowling either?? Did you encountered the same? If yes, what was your solution?

 

 

thanks in advance, artto

[Zlin 50]

I think there plenty of us who want to read more on how your 2nd Zlin flies..btw did your first Zlin pull left only at the take of or in the air as well?

 

I hope you'll have your "quality time" and manage to go flying..

 

 

[Zlin 50]

Thanks Stephen,

 

Thank you for your comment. I think I will add some side thurst, too. I'm sorry to hear about your lost of the Wot 4 and other circumstances that haven't allowed you go flying..

 

artto

Edited By Artto Ilmanen on 30/07/2011 05:45:50

[Zlin 50]

Hello all,

 

It seems the engine sits to the right off centre,when looking from the front? (Saito 125) Anyone else having noticed the same? Maybe added side thrust is needed..I don't know.

 

Any hints? / suggestions?

 

rgds artto

[Zlin 50]

Anyone using a Saito or Laser engine?

 

rgds Artto