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Laser Engines development.


Jon H

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The next batches of engines are almost ready and will be heading out the door in the next week or so as i get them all run up. I will be glad to get them out as these things are like tribbles! I cant move without one being in my way. Still, better than having none. 

 

 

Next, a bit of a frustration moment. A number of customers who have had/want these engines have asked me about mounting it inverted so the main needles point down. On the face of it this is a completely reasonable request, but there are issues. 

 

This engine was designed to be nailed on the front of an ARTF sport/aerobatic/scale model (like Ron's WWXL above) with the minimum of effort for club level enjoyment. The needles pop out the top of the cowl for easy adjustment and the tank can live where the model designer intended it to live. Cooling is nicely set up, exhausts out the bottom, very little adjustment needed on slow run needles from the factory as the setup is the same as the bench...its a win all round. 

 

This is in comparison to our V twin where the primary complaints about fitting a V in the same model were the need to move the tank, added work to baffle the engine for cooling, difficulty tuning the engine as many really struggle with slow run tuning which needs altering in this configuration, and the contortion needed to reach under the cowl with the engine flat out to tune the main needles and not burn your hand on the exhaust. The WWXL is especially bad for this as its a biplane. 

 

if you flip your flat twin over as the needles are offensive to the eye you not only design back in the two problems the engine was designed to remove (reach around needles and needing to lower the tank) but you also design in a new problem as the exhausts are now on top of the engine and you need to route the pipes down and round to get them out of the bottom of the model. This would be a complete nightmare for cooling and reliability not to mention difficult to make. I have already had one 'inverted' engine back as it apparently wouldnt run and yet it worked perfectly on the test bench when i tried it. Tank placement and slow run needle tuning were the cause of the problem due to the inverted installation but the customer was unable to diagnose and solve it. I have even heard ideas of removing the link rod and turning the carbs 90 degrees with one servo for each carb mixed on a throttle curve with reversed this and that...no. Please no. Its been tried on the V twins in the past...no, just dont even try it. Slop in linkages, servo geometry and a bunch of other stuff just makes this a reliability and setup nightmare. 

So please for the sake of my sanity just install the blasted things the right way up as they were designed to be used this way and it will make everything so much easier. Its almost like some people deliberately go out of their way to make their own lives difficult and it boggles my mind a bit. especially after i did all the hard work and made an engine you dont need to mess with in the first place, and its all to solve the non problem of needles poking out of the cowling. They need adjustment, so you need access! If you cut the holes neatly they will hardly show and you can even make little shrouds for them if you want to make it as neat as possible. 'But its a scale model'...If needles poking out of the cowl are really that offensive then it is the wrong engine for the job and an inverted v would be better as you remove the exhaust problem you get with the inverted FT. And define 'scale model'. If its a championship entry then sure i get it. If its a club scale model then reliability and simplicity will always trump exact scale fidelity. All of my scale models have non scale engine bits hanging out be it an exhaust, a head, needle

 

I am not trying to offend anyone that was considering mounting the engine inverted, this is more a plea to consider the broader ramifications as i cannot help with technical issues if the engine is not installed as it is supposed to be. 

 

If needle poking really is the end of the world the only solution i could offer would be to design and sell a remote needle kit but remote needles have caused problems for years so that is not an ideal solution either. If however this is deemed to be something folk want then i can do it and it would be compatible with all the engines in our range. 

 

 

 

 

 

 

 

 

 

 

 

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Based on my experience of fitting the 200FT to the WWXL, if the model had been new (and not having 3 previous engines mounted!) the installation would have been dead easy. As Jon says above, the fuel tank would have been in the designer’s location and the work required to the cowl somewhat easier. Even cutting the cowl to make it a ‘ clam’ has the advantage that it’s easier to get the cowl on and off and half of it can be left in place when accessing the engine. Yes there are 2 needles that stick up but you soon don’t notice them. The 2 attached photos are from the ‘other’ thread.

 

5FB3D65F-A02B-473D-A3DC-9CD4E74E5581.thumb.jpeg.228362943297201acf8a64ae7fdab565.jpeg

 

B7F08A53-12E4-4805-A756-5690666AD277.thumb.jpeg.81ca9c97148f42035d9f7890b008b8eb.jpeg

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  • 2 weeks later...

image.thumb.jpeg.8cbbddd71025453fbe44aef7ca44098d.jpeg
 

I totally agree re the accessibility of the main needles. I have two small holes atop the cowl and short L shaped extensions poking through for the Fury. I was a bit iffy at first about cutting the holes but as soon as the model is more than a few metres away you just don’t notice. Makes tuning a lot easier, though it’s a cowl off for mucking about with the low end adjustment. One of the benefits of the L shaped extensions is that they give a visible reference of my adjustments. 

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While old allen keys are convenient, I prefer small L extensions from softer wires or short pieces of braided cables that are sweated with solder at both ends to take the set screws snugly without fraying the ends. 

Advantage being that in a prang, stiff wire needle extensions can lead to damages to the needle or the housing. 

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The hole in our needle is designed for a 1.5mm allen key and i recommend these are used. Braided cables are not recommended as their resistance to torsion is poor, especially if it is unwinding the twist in the cable. This makes accurate needle adjustment very difficult due to the rather springy and indirect drive. I have this exact issue with an ASP 160 twin using a braded extension. Admittedly its quite long and perhaps an extreme case, but its very irritating. 

 

While the allen keys are more likely to cause damage in the event of an accident you have already crashed by that point anyway so being worried about damage in that event is a bit pointless. Also how often do you break needles? Suffering a lifetime of inaccurate tuning to save yourself buying a needle once every 5-10 years seems a poor trade. However, if its a concern use some fine carbon fibre rod with a nub glued on the end as it will snap like a carrot when you bash it ? 

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Sweating some solder on to the ends will get rid of the said lifetime of inaccurate springy needle adjustment issues. But given that I hardly tweak my needles unnecessarily I will continue to use the repurposed scrap cables ? 

While gluing in a nub on the outer end of the carbon rod will be perfect, not many will wish to glue the rod in to the needle. And we do know what happens to those carbon rods when we try and tighten a set screw on to them. Don't we??      

 

In the end we do what works for us and we prefer. Back to Lasers then ? 

Edited by Manish Chandrayan
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You cant sweat solder into the whole length though, so the middle is still all floppy. But, if you never touch your needles clearly accurate tuning is not something you are worried about anyway ? Engines should be retuned at the start of every flying day. Why settle for imperfect? it only takes a few seconds. 

 

As for carbon rod and grub screws they only break if you use the wrong size rod, and/or you then use a 2 foot spanner to nip up a 3mm grub screw. You dont need that much torque, just go easy on it. 

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Quite coincidental thus discussion about extending the needles using old allen keys (as per the Laser intent). My latest model, the Mustang powered by a 160 in line had to have a belly landing due to UC failure (I have already posted the bid of this). Whilst it did land on its belly rad inevitably the nose came in contact with the ground but the Allen key extended needles did not suffer any damage!

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1 hour ago, Manish Chandrayan said:

As long as we agree to disagree, all will be fine on the Earth  

 

Everything i have said is the official position of the manufacturer of the product. There is no agree to disagree. 

 

 

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  • 2 weeks later...

Quick update and a show of hands needed. 

 

160 and 200 flats are still proving popular and i am doing what i can to keep up while trying to fit in other work as well. 

 

The 300 flat twin has been abandoned in favour of a 310 as we are near the end of our NOS 150 liners and there is no point making more so we might as well go for gold and make it an FT-310 from the get go. The 300v will then run out the last of the liners we have and then it too will be killed off and turned into a 310v. 

 

The next thing i need is a show of hands. Do i continue with the flats and make a 360 size, or should i focus on a 360 inline instead? Personally i would like to do both (and my 3 radials), but i am told that rapid firing so many new products out at once is bad due to the time involved meaning we wont be able to do anything else. I am sure i mentioned that at some point. its almost like we need separate production and R&D staff and not just one bloke doing everything...who knew? ?

 

Anyway, 360 flat twin for probably 700 quid or so, or an inline of probably 850? Both low oil glow. My interest is in the inline as it has no competitor in the market, would fit a great many WWII type models, and, most importantly, i need about 4 for my own models! The 360 flat would also be very handy for a variety of models and could be a competitor to the saito 57 and 61 twins if i bolt my petrol bits to it. i have designed the inline to accommodate petrol as well. Petrol versions would be more expensive clearly due to all the extra bits but maybe £900 and £1100 respectively? Not sure, but that would be the ballpark i suspect. 

 

Let me know your thoughts but please only vote if its an engine size/type you are actually in the market for in the foreseeable future. If the answer is both, say both and i will see what i can do to drive things forward. 

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Hi Jon,

 

Thank you for the update. The 300 and upwards are too large for my sizes of models, so I'll not vote thanks, but I am interested in the smaller inlines, 160i or 200i. More so after having watched Ron Gray fly his 160i powered Mustang on Saturday. Gorgeous!

 

Are the 160i and / or 200i going to be produced for sale any time soon? The flat twins seem to have overtaken them.

 

Thanks.

 

Brian.

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Yea the inlines went to the back burner over winter as they needed air time and with winter weather dampening down flying hours there was no point building more so i went ahead with the flat instead. I have been meaning to get back to them but the flats have proven even more popular than expected so it delayed me a bit. 

 

I do have inline parts coming together and was doing an inventory of what i have so i can build more. If the planets align i might even have made some headway by the end of the month. 

 

So we dont get too far off track here give me a call this afternoon if you like and we can go through all the stuff you need to know, your model choice and all that. 

 

In the meanwhile, i am off to run up some FT200's and my prototype 310v from a few years back. 

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