Laser Engines - Technical questions

[Jon H]

Answered on the Spitfire thread Artto

 

Don, sorry i missed this. 4 is plenty. There is a boring story behind the 8 holes in the larger mount, but the smaller one just copied it and ended up with 8. 

 

Scott, in fairness, the first 3 minutes i was just laughing at you. Then i saw the mount and added a few for that 😉 

[Artto Ilmanen]

Hi Jon,

 

I tired to search for the latest Laser factory recommendation for suitable fuel mix but could not really find an answer:

 

As you know, my engines are 2 x 150, 240V and a 300v all manufactured between 2004-2013.

 

I just checked and it turns out I have plenty of Aerosave, ML 70 (+ some sical), Klots KL 200. All these are high viscosity good quality oils.

 

As per earlier discussions I have been blending my fuel 5% nitro, 10 oil (or 9%oil +1% Sical) and the rest methanol.

 

Is this still your recommendation?

 

Or could I go for 5% nitro, 7% oil and the rest methanol? (which is the blend, as fas as I know, the blend of the new Laser 5 Pro fuel) Or should one avoid this low oil % if self-mixing the fuel, just to maintain safety margin?

 

thanks

 

Artto

[Jon H]

For fuel mixed at home we recommend 5 nitro and 10 oil as it makes the maths easy! 

[Artto Ilmanen]

Thanks for the prompt reply, Jon!

 

While I can't see issues with my mathematical skills to calculate the correct blend I will follow this rule. 😀

 

 

[Don Fry]

1 hour ago, Jon - Laser Engines said:

For fuel mixed at home we recommend 5 nitro and 10 oil as it makes the maths easy! 

Is that by volume or weight?

[Jon H]

6 minutes ago, Don Fry said:

Is that by volume or weight?

 always volume as the ingredients are different densities 

[Nick Somerville]

Slightly off topic but I consider worth mentioning. I subscribe to the Laser Engines FB group and purchased a V200 advertised thereon by a Georgia Ward. Without going into details I was scammed. Turns out he has sold Laser Engines he has said to have purchased from ‘Steve’ at Kings Lynn Models before but also these never appeared. Naturally I feel a complete idiot for being scammed for the first time in my life and trust I have learnt my lesson. I do like Laser engines though.

On a positive note I rarely have good things to say about banks. However, after a lengthy phone call to Lloyds, they have refunded the the whole amount regardless of whether they can retrieve it from the scammer.

[RottenRow]

Nick, this guy has been doing this for years… using the BMFA site and eBay in the past.

Previously it was radio gear, cars and other items being sold that never existed. He often had copies of invoices or receipts from Kings Lynn models that appeared to prove that he had the items concerned.

He has been convicted of several of these crimes in the past but the ridiculously lenient judicial system we have just allows him to do it again and again. 

As you say, off topic but worth a mention. He has also previously used other names, one being Michael Ayers, but doesn’t appear to have any problem with using his own name either!

He is known to the police in Norfolk…

At least you got your money back from your bank.

Brian.

[Artto Ilmanen]

Nick,

 

I saw your post on FB - Sorry to hear of your story. Fortunately you did not loose your money, eventually. Also A lesson to learn for myself:  I have been happily transferring money to random hobbyist (in Finland, where I live) with confidence I was going to be provided the items as agreed. Yet I have never been scammed but, hey, that had been your experience too, Nick! 

By the way, I actually posted a my add to swap my 240V to a 300V as I will be starting a project to rebuild a Yellow Aircraft Spitfire and a 300V might be a better engine for the model.  Jon says he had been thinking of a 240V for his YA Spitfire but eventually decided on the 300V, though. And as my 240V is sitting on a shelve without home in anyways. Now that you posted your horror story of a scammer I'm not expecting many contacting me on my add, though..😃

Edited February 16, 2023 by Artto Ilmanen

[Jon H]

30 minutes ago, Nick Somerville said:

I was scammed

 

What is wrong with people? Get a job you lazy beggar and stop ripping people off. We should bring back the stocks for people like this. 😡

 

Artto, as the 240 and 300 share the same mount you could always build the model with the 240 and then swap it later if you find its not enough for your taste. You would need to make some mods for a 300 to fit as the exhausts hang out the sides. I plan to make new exhausts for mine as its ugly otherwise. 

[Artto Ilmanen]

57 minutes ago, Jon - Laser Engines said:

 

What is wrong with people? Get a job you lazy beggar and stop ripping people off. We should bring back the stocks for people like this. 😡

 

Artto, as the 240 and 300 share the same mount you could always build the model with the 240 and then swap it later if you find its not enough for your taste. You would need to make some mods for a 300 to fit as the exhausts hang out the sides. I plan to make new exhausts for mine as its ugly otherwise. 

 

Very true, Jon. 

 

I did a custom exhaust for my GP Super Chipmunk / Laser 150 so I do not fear that process too much.

 

But, I'm not very much fancying the cylinders of a 300V poking outside the YA spitty cowling. Not much, but still. That's one of the reasons I was toying with idea of a reduction gear as my understanding is the YA spitty calls for a prop larger than 18X8 which is a good prop for the 240V. I know Jon, that you have been running the 240V with a 19X8 so maybe that could be ok. However, the reduction gear, at least theoretically, would allow the 240V to reach its best power (at 9000+ rpm on ground) yet enable a large propeller to give good thrust for vertical maneuvres. But then again, theory is theory and maybe nothing to be gained in practice. Also in commercial wise not a business for Laser to develop & sella a reduction gear setup. Perfectly understandable.

 

Also, as time goes on who knows if there will be an inline 310 (I suppose there won't be any new configuration based on the 150 cylinder) which could be the "crème de la crème" solution for the YA Spitfire. Maybe it's worth the wait 🙂 even though the inline requires substantial rebuilding of the model to handle the length of the engine plus the cooling arrangement.

 

[Jon H]

9000 is a bit quick, even for a 240. 8000-8500 is better and i run mine around 7300 at the moment in the hurricane. Its pretty happy with that. 

 

I wont be doing a 310 inline as i cant fit it in the crankcase. I would need a bigger case, like the 180, so if i am doing that i might as well skip the 300 and do a 360. I already have the drawing, i just have to convince the boss to build it. Again, no parts, no enthusiasm, no progress. 

 

Its a shame as a 60cc inline would not be prohibitive as a glow, would have no competitors, and would suit a great many models in the 80-100 inch range. I mean i have about 5 models at home right now that would accept one. Alas, no. 😞 

[Artto Ilmanen]

ok Jon,

 

I think my 240V run about 8200-8400 with the Menz 18x8. 

 

Is the prop 19x8 Menz what you are running in the Hurricane? I assume with larger prop / 7300 on the ground you are more after thrust in verticals than horizontal speed?

 

[Jon H]

47 minutes ago, Artto Ilmanen said:

ok Jon,

 

I think my 240V run about 8200-8400 with the Menz 18x8. 

 

Is the prop 19x8 Menz what you are running in the Hurricane? I assume with larger prop / 7300 on the ground you are more after thrust in verticals than horizontal speed?

 

 

I forgot I changed to 20x8 aerostar but cant remember the revs. I will check next i fly. I think 7000? not sure. 

 

But yes the Hurricane was too quick and i wanted to keep the speed in check. 

[Artto Ilmanen]

Thanks Jon,

 

Perfect, no rush but always got hear of results with different prop setups

[thebluemax]

Hello Jon,

Hope all is well. 

I just got my hands on a GTM 1/4 scale D8 kit.  The recommended engine is the 200V, which is shown on the plans.  Assumng the 200V is still a good choice for this kit, I was wondering if the FT-200 would be a better option?  Looks like the FT-200 would fit inside the cowl and the cylinder heads would be closer to the center line of the prop shaft.  In either case a Laser is in the future for this kit. 

thanks in advance for your time,

Bill  

 

 

 

[Jon H]

Hi Bill

 

An FT or a V would do well here but the FT would get my vote as it would be easier to cool. Tank placement would be easy, exhaust too. 

 

If you want a v i can sort it, but i think the FT would be a slightly better choice

[thebluemax]

13 minutes ago, Jon - Laser Engines said:

Hi Bill

 

An FT or a V would do well here but the FT would get my vote as it would be easier to cool. Tank placement would be easy, exhaust too. 

 

If you want a v i can sort it, but i think the FT would be a slightly better choice

Thanks Jon for the quick response.  Ok for the FT. I would like to get on the waiting list for the FT.  I am already on the list for the 310 which is for my  Platt FW-190.

 

I will send an email with my info.  Also need to update my info on the 310 waiting list.

Edited February 16, 2023 by thebluemax
added sending an email

[Artto Ilmanen]

Jon, Gentlemen,

 

I'm learning something regarding dome nuts - maybe this is of interest for other Laser enthusiasts, as well:

 

I want to have a dome nut for my Great Planes Super Chipmunk and Laser 150 so I contacted Sarik Hobby and Just Engines. It turned out Just Engines have 2 options:

 

• one option is to use a dome nut that can be recessed so steel propeller nut + washer can be used to secure the propeller in place: The dome nut is recessed so it just covers the single steel nut (5mm or about 4 threads left to tighten the dome nut):

 

https://www.justengines.co.uk/shop/accessories/spinners-domed-nuts/medium-domed-spinner-nuts/?v=f0aa03aaca95

 

• the other option is to leave out the steel nut and secure the propeller with a washer + dome nut. In this case 11mm of thread length left to secure the propeller - and no recess of the dome nut (as no steel nut to cover)

 

hmm.. could one of these alternatives work? Also, when an electric starter is being used? Which might be the best one?

 

Some pictures of the propeller axle thread lengths with and without a steel nut

 

 

 

 

[Chris Walby]

IMO, either. Won't go into detail but the "double nut" requirement is not necessary on Laser engines (Jon told me so!).

If you are using an electric starter then the single domed nut might be a better option (do use this myself) is ok, although I have engines with nut and domed nut, but that's because the domed ones cam from JE like that.

 

Should not be an issue, but with wooden props you would have to take the domed nut off to check/tighten the std nut whereas if its just the domed then its easier to check/tighten.

 

PS the kick back/prop throwing that other engines do is less lightly due to the less radical valve timing used by Laser engines. Note, less radical does not = less powerful, just an easier engine to live with. Works for me!

Edited March 10, 2023 by Chris Walby

[Artto Ilmanen]

Thanks Chris,

 

Sounds promising. I have never used a lock nut with Laser engines and I have never had any issues. The only thing that was puzzling me is the dome nut is of aluminium and thus less capable to take stress of tightening the prop vs a steel nut. 
 

[Paul De Tourtoulon]

I have a couple of 4 strokes with domed nuts, I use the two lock nuts and bore out the dome nuts to hide them.

[John Rickett 102]

This is a Just Engines domed nut on a Laser 155. The original washer and nut are retained.

 

 

 

It will accept a starter. The trick is to arrange the glow to come on after the starter has been applied and then there is no kick back. 

[Don Fry]

2 hours ago, Artto Ilmanen said:

Thanks Chris,

 

Sounds promising. I have never used a lock nut with Laser engines and I have never had any issues. The only thing that was puzzling me is the dome nut is of aluminium and thus less capable to take stress of tightening the prop vs a steel nut. 
 

But still good enough. 

[Artto Ilmanen]

Ok, thanks for everybody for the hints and sharing experience.

 

It seems that both OS and Laser 155 have longer prop threads than Laser 150. With a Laser 150 the single dome nut might the most straightforward way to go as Chris pointed out earlier. 

 

I try to ensure the dome nut, whatever I buy, is made of good quality aluminium and not from the most cheapest and softest chinese stuff.