Laser Engines - Technical questions

[Jon H]

13 hours ago, Artto Ilmanen said:

Any thoughts or first hand experience on some set-up to measure engine temperature? 

 

As always i recommend you start it, tune it, and fly it. Forget all the baggage, just fly it. 

[Artto Ilmanen]

9 hours ago, Frank Skilbeck said:

Artto have a look at the Powerbox PBS-T250, but you'd need the programming lead to change the operation to Futaba. 

 

Thanks Frank,

 

Yes, with Futaba you need to purchase the programming lead which is 29€. But then again, this is one-off cost that can potentially be used for other purposes, too?

 

Anyways, so far this seems to be maybe the best alternative - at 49€ you get the temperature unit with 2 temperature probes.  And the unit can handle up to 5 temperature probes (additional probes can be purchased separately for 9,8€ unit price which is quite reasonable).  Anyways, much more attractive a solution compared to genuine Futaba which is 100€ for just one temperature probe.

 

One thing that I do not like is the way the manufacturer suggest to mount the temperature probe:

 

extract from the manual (https://www.powerbox-systems.com/uploads/tx_pbsdocuments/6621_BA_PBS-T-250_EN.pdf):

 

"..The temperature sensors are designed to be attached to the cylinder head using a screw-lug. Drill a 3.5 mm Ø hole in one of the cooling fins, then fix the temperature sensor in place securely using a suitable self-tapping screw or M4 machine screw. A small quantity of heat-conductive paste under the sensor improves the temperature measurement."

 

-> in no way I'm going to butcher my beautiful Laser engines! There must be another way to do this. A picture of the temperature probe:

 

https://www.powerbox-systems.com/produkte/sensoren/temperaturfuehler.html

 

 

 

 

 

 

 

[Artto Ilmanen]

19 minutes ago, Jon - Laser Engines said:

 

As always i recommend you start it, tune it, and fly it. Forget all the baggage, just fly it. 

 

Jon,

 

I see your point. This being said, as you pointed out in another conversation my the PTFE piston pads of my 300V had deformed somewhat indicating the engine had run a tad hot (while not overheated). The model on which the engine sits has baffling helping with cooling the engine. Therefore I feel tempted to try, maybe temporarily, the temperature sensors to tell me if my cooling ducting is working or if  the cooling arrangement still needs some changes.

 

 

 

 

 

[Jon H]

6 minutes ago, Artto Ilmanen said:

the PTFE piston pads of my 300V had deformed somewhat indicating the engine had run a tad hot (while not overheated)

 

This is extremely common and not a big issue. I would say that 6 out of 10 engines i service are like this and the deformation i mentioned was relatively insignificant. I only changed them so it didnt get worse. Some engines over the years have had the pads melt to the point where they lock up the piston, but i think i have only seen about 4 or 5 examples of that in the whole time i have been here. Often the heat that melts the pads is partly due to friction on the cylinder wall. PTFE is low friction, but over time it has an effect. 

 

But, had i not mentioned the pads and just swapped them like i normally do (and did on one of your 150's) you would not be worried about heat. My idle comment of 'yea it might have run a bit hot so double check your baffles' has been conflated into a Chernobyl Reactor 4 situation when it was nowhere near that bad. If you fit a temperature sensor you will be even more worried about heat than you are now. I cannot give a temperature limit figure, so knowing how hot your engine is will be not be of any use as you have no value to compare it to. Quite often engines are at the hottest on the ground while having the last rpm wrung out of them. This is why i vague up my rpm numbers as i know a number of customers who will not be satisfied to see 8400rpm if i said it should do 8500 and will wring the neck of the thing trying to get the extra 100 revs. 

 

My point is too much information can be extremely detrimental and very distracting. While you are worrying about your 'missing' 100rpm or are focused on your tx beeping at you about engine temperature you arent giving your full attention to flying the model. Without a recommended temperature limit for the engine temperature sensing is basically a curiosity and of no real value anyway so you might as well just remove the distraction.  

 

Why dont we provide temperature data? The reason is we simply do not know what the limits are. I can make a very well educated guess, but we do not have the resource to test it in a meaningful way. To do it properly and provide real data you would need to endurance test countless engines at different temperatures and observe the results after hundreds of hours of running just like they do will full size engines in aircraft, cars etc. The time involved, the facilities required, and variation in model fuel/oil quality used also makes the job completely impossible. 

 

So i am going to tell you the exact same thing i have been telling you the last 10 years. Install it right, tune it up and just fly it. Dont worry yourself into an early grave, just fly it. 

 

 

[Artto Ilmanen]

3 hours ago, Jon - Laser Engines said:

 

This is extremely common and not a big issue. I would say that 6 out of 10 engines i service are like this and the deformation i mentioned was relatively insignificant. I only changed them so it didnt get worse. Some engines over the years have had the pads melt to the point where they lock up the piston, but i think i have only seen about 4 or 5 examples of that in the whole time i have been here. Often the heat that melts the pads is partly due to friction on the cylinder wall. PTFE is low friction, but over time it has an effect. 

 

But, had i not mentioned the pads and just swapped them like i normally do (and did on one of your 150's) you would not be worried about heat. My idle comment of 'yea it might have run a bit hot so double check your baffles' has been conflated into a Chernobyl Reactor 4 situation when it was nowhere near that bad. If you fit a temperature sensor you will be even more worried about heat than you are now. I cannot give a temperature limit figure, so knowing how hot your engine is will be not be of any use as you have no value to compare it to. Quite often engines are at the hottest on the ground while having the last rpm wrung out of them. This is why i vague up my rpm numbers as i know a number of customers who will not be satisfied to see 8400rpm if i said it should do 8500 and will wring the neck of the thing trying to get the extra 100 revs. 

 

My point is too much information can be extremely detrimental and very distracting. While you are worrying about your 'missing' 100rpm or are focused on your tx beeping at you about engine temperature you arent giving your full attention to flying the model. Without a recommended temperature limit for the engine temperature sensing is basically a curiosity and of no real value anyway so you might as well just remove the distraction.  

 

Why dont we provide temperature data? The reason is we simply do not know what the limits are. I can make a very well educated guess, but we do not have the resource to test it in a meaningful way. To do it properly and provide real data you would need to endurance test countless engines at different temperatures and observe the results after hundreds of hours of running just like they do will full size engines in aircraft, cars etc. The time involved, the facilities required, and variation in model fuel/oil quality used also makes the job completely impossible. 

 

So i am going to tell you the exact same thing i have been telling you the last 10 years. Install it right, tune it up and just fly it. Dont worry yourself into an early grave, just fly it.

 

 

Hi Jon,

Thank you for your advice - I believe what you wrote is good, not only for me but also for many other Laser enthusiasts as I happenen to be not the only one thinking of measuring Laser engine temperatures.

 

I see - so the PTFE piston pads deforming is, like you write, pretty common. I thought my case more like an unusual case but I was wrong. Anyways, for that reason I may have overcomplicated things again.  Sorry for that. I do want to follow your advice as you, as the manufacturer representative, know best the right use of the engines. This being said, this cooling / ducting / baffling theme and what are the associated good working practices can sometimes be "black magic". Hence the use of technology to prove things are fine can feel alluring. But anyways, I content with your help, Jon.

Edited October 31, 2023 by Artto Ilmanen

[Frank Skilbeck]

7 hours ago, Artto Ilmanen said:

 

"..The temperature sensors are designed to be attached to the cylinder head using a screw-lug. Drill a 3.5 mm Ø hole in one of the cooling fins, then fix the temperature sensor in place securely using a suitable self-tapping screw or M4 machine screw. A small quantity of heat-conductive paste under the sensor improves the temperature measurement."

 

-> in no way I'm going to butcher my beautiful Laser engines! There must be another way to do this. A picture of the temperature probe:

 

https://www.powerbox-systems.com/produkte/sensoren/temperaturfuehler.html

 

 

 

Yes, that could be a problem, but could you use one of the existing bolts, either cylinder head or the exhaust/carb retaining bolts.

 

We've used the multiplex temp dual sensors on my mates Moki 215cc radial to check temps on two cylinders, but these were just pushed between the fins and sort of held in place with a tie wrap a bit further back, so how accurate they were is open to question.

 

We did talk to one of our mates who's into electronics about making one that used infrared sensors, so they could standoff the cylinders, he knocked up a proof of concept prototype using his Frsky gear and got it talking to the transmitter, but then other things got in the way and it didn't go any further.

[Artto Ilmanen]

Hi Jon & gents,

 

I'm installing a Laser 150 on my ESM Focke Wulf

 

If side mounted the top of the tank seems to be about 7-8 mm higher than the centre for the carb: see picture if no mods done

 

If I understand your instructions correctly  the top of the tank should be in line with the the spray bar?  See the other picture

 

Anyways, if I lower the tank as instructed I need to either find a tank which is not more than 50mm of height, which is the space available until the wing comes in way (the 12 fl oz Dubro in the picture is 57mm). Or I can modify the wing to have some more space for the tank.

 

Anyways, the right size & shape tank might be the easiest solution.  I came across this, Sullivan Flexi tank, any experiences?  According to what the manufacturer says "they can be reshaped with a heat gun if desired."  -> maybe this could help with reshaping the tank to fit into the 50mm space available.

 

https://sullivanproducts.com/product/rectangular-flextank/

 

As a side note, for some reason I haven't been able to find a tank of 50mm of height as max  (Sullivan, Dubro, Kavan) 

 

 

Another route to ensure the tank height is correct is I could, of course, rotate the engine somewhat so the cylinder would be pointing to 10 o'clock or something to help with respect to the tank height vs the carb. See picture. Not sure how elegant this is, though.. 

 

 

Any thoughts or recommendations?

 

Artto

 

 

 

 

 

 

 

[Chris Walby]

See what Jon has to say, but IMHO you are over thinking this a bit! I have had to take quite a lot out of fuselages and wings to get engines and tanks lined up when inverted and the bottom line is "you only have to do it once". I do prefer engines at 9 o clock from a tuning, priming and tank position, but then I am much less fussed about seeing the cylinder head on the ground (people must have very good eyesight if they can see a cylinder head in flight!).

 

By the time you have a bit of air gap in the tank I think it will be ok and as long as the tank is not too far rearward in relation to the engine all will be ok

[Paul De Tourtoulon]

I would use the top photo, it looks perfect to me.

[Artto Ilmanen]

Thanks gents,

 

I do not mind modifying the model if needed. The only thing I’m thinking is the wing - will it become weaker if I carve it 5-7mm to make room for the tank.

If I Interprete Jon’s instructions right the second picture is how the tank should be in line with the carburetor?

Edited November 12, 2023 by Artto Ilmanen

[Ron Gray]

If you line the tank cut out with ply or lite ply then you won’t weaken the wing, my ESM Hurricane and Mustang have both been altered like that with no ill effect.

[Artto Ilmanen]

39 minutes ago, Ron Gray said:

If you line the tank cut out with ply or lite ply then you won’t weaken the wing, my ESM Hurricane and Mustang have both been altered like that with no ill effect.

Thanks Ron. This makes sense.

 

As a side note - have you been flying your Bearcat with the 240V? What are your experiences?

 

I had been thinking of a 240V for my Focke but having spoken with Jon the 150 seems to be a better choice for the Focke

[Ron Gray]

I haven’t flown the Bearcat for a while, it is a bit overpowered with the 240v but I needed the nose weight anyway!

[Artto Ilmanen]

18 hours ago, Ron Gray said:

I haven’t flown the Bearcat for a while, it is a bit overpowered with the 240v but I needed the nose weight anyway!

Thanks Ron,

 

Yes, these models seem to be tail heavy easily. I try to avoid use of unnecessary ballast by mounting the rx batteries inside the cowling. We'll see.

 

Anyways, I think I'll go for the side mount route with the 150. After second inspection I noticed that I don't need any more cut out of the wing at all as there is already some by the factory.  What comes to the tank height vs carburetor I found a picture by Jon on the other thread so I believe it's clear now. The read line in the picture is "in the middle of the carb".

 

 

 

 

 

Edited November 13, 2023 by Artto Ilmanen

[Jon H]

On 12/11/2023 at 05:44, Chris Walby said:

you are over thinking this a bit

 

Agreed. 

 

90 degree side mount and its job done with the tank aligned in the position the kit is designed for. 

 

1 hour ago, Artto Ilmanen said:

mounting the rx batteries inside the cowling

 

Not recommended. Batteries are not impressed by heat, oil and vibration so tuck them up behind the firewall out of harms way. If additional ballast it needed (it will be) take another engine mount and install it under the engine. You can them mount the lead on the 2nd engine mount and get it a long way forward for maximum effect. 

[Artto Ilmanen]

1 hour ago, Jon - Laser Engines said:

 

Agreed. 

 

90 degree side mount and its job done with the tank aligned in the position the kit is designed for. 

 

 

Not recommended. Batteries are not impressed by heat, oil and vibration so tuck them up behind the firewall out of harms way. If additional ballast it needed (it will be) take another engine mount and install it under the engine. You can them mount the lead on the 2nd engine mount and get it a long way forward for maximum effect. 

 

Thanks, Jon. I just want to follow your instructions as rigurously as possible. 🙂  And as such, some modification, although pretty minor, is needed  (lower the tank) to get the tank height as instructed by you.  It's hard to know when and to what extent one can deviate from the official instructions.

 

Thanks for the hint concerning the rx batteries. While I have never had any issues in the past when having them mounted inside the cowling, maybe I have just been lucky!

 

 

[Paul De Tourtoulon]

Those old Sanyo 1.700 SCR cadmium nickel battery's were good the one in my Marutaka Enya 90-4c finally died Sunday, it was under the fuel tank wrapped in a plastic bag and surrounded with foam.

 

 I have only fixed one battery element to pre-heat the plug in the engine cowling, as Jon says Don't put the radio battery there.

the second( photo ) battery is one that was held in place with Velcro and a plastic tie, as you can see the soldered steel ribbon that connected them up sheared, it has been powered by vibrators, KB.61, OS 80fs, Rcgf 15cc, Enya 120-4 and lastly Saito 100🙃

[mikem65d]

Gd morning from the US,

 

Is there any contact info for Neil Tidey?

I use to chat with Neil from time to time back in the early 2000's.

Neil was always the nicest modeler to talk to about his Laser design and always took care of customers.

 

Thx

Mike

Edited November 21, 2023 by mikem65d

[Jon H]

Hi Mike

 

Neil retired many years ago and is no longer connected with the company. As a result it is not appropriate to share his personal contact information. 

 

If you need any technical assistance i can deal with that no problem. 

[Jason Channing]

1 hour ago, mikem65d said:

Gd morning from the US,

 

Is there any contact info for Neil Tidey?

I use to chat with Neil from time to time back in the early 2000's.

Neil was always the nicest modeler to talk to about his Laser design and always took care of customers.

 

Thx

Mike

If you PM me ill pass on your details to Neil and he can contact you.

[Jon H]

1 hour ago, Jason Channing said:

If you PM me ill pass on your details to Neil and he can contact you.

 

I think you are missing the point. Neil has retired, has no connection to the company and his privacy should be respected.

 

i just spoke to Neil to make sure i was not misrepresenting him and he agrees with what i have already said. He asks that his personal information is not shared in any form for the reasons i have stated above. 

 

 

 

 

[mikem65d]

13 hours ago, Jason Channing said:

If you PM me ill pass on your details to Neil and he can contact you.

thank you Jason

[mikem65d]

13 hours ago, Jon - Laser Engines said:

Hi Mike

 

Neil retired many years ago and is no longer connected with the company. As a result it is not appropriate to share his personal contact information. 

 

If you need any technical assistance i can deal with that no problem. 

No John,

no technical questions

I learned all I have about his design back in 2007-9 from Neil.

This is an entirely differnt inquiry and one that only Neil can approve.

 

 

[David Davis 2]

This is not really a technical question either but there is a bloke over on the Laser Engines Facebook page who is under the impression that the V twins are no longer available owing to the popularity of the flat twin. His post is quoted below.

 

" ... I was told by Laser that there’s no interest in making them as the flat twins are in demand. Heck I have had no luck in bya few pieces I want for a 200V that came into my possession."

 

Is this true?

[Jon H]

5 hours ago, mikem65d said:

thank you Jason

 

So you both have chosen to ignore Neil's request that he not be contacted? If so that is pretty disgraceful. 

 

5 hours ago, mikem65d said:

This is an entirely differnt inquiry and one that only Neil can approve.

 

If it is anything engine related that is most unlikely.

 

2 hours ago, David Davis 2 said:

This is not really a technical question either but there is a bloke over on the Laser Engines Facebook page who is under the impression that the V twins are no longer available owing to the popularity of the flat twin. His post is quoted below.

 

" ... I was told by Laser that there’s no interest in making them as the flat twins are in demand. Heck I have had no luck in bya few pieces I want for a 200V that came into my possession."

 

Is this true?

 

 

Experience has proven that most of our customers struggle with installing and operating the V twins and this has gotten worse and worse over the years i have been here. The FT series was designed to be easier to install and easier to use in the current ARTF offerings most people now fly and they have been more or less trouble free since roll out. Consequently i generally recommend a flat over a V in most cases as it saves the customer the hassle of technical problems and it saves me the time of having to deal with it. As i cant keep the FT's in stock, and they are the model i would offer to most people, there is no point diverting limited resources to building the V's i wont sell. As always, the problem would be solved by just building more engines, but as i cant do that with the resources i have i will prioritise the flats for the time being. 

 

Spares and support are available for the V's in service though so i do not know what he's talking about there.