Laser 70- short review
Brian D. Felice
that I've seen 'in the flesh'.
The particular engine is a 70, the smallest Laser currently makes.
Quality and workmanship are obviously extremely good. Perhaps the most
notable example of this is the rocker cover; while this is a trivial
example, it does show the attention to detail and desire to make a first
rate product. It's fully machined from solid aluminum and overcuts are
nearly nonexistent. The rest of the engine shows the same commitment and
attention to detail.
It's often mentioned how short Laser engines are compared with other
4 cycles of similar displacement and this is true. The Laser 70 is
actually slightly shorter from the bearer beams to the top of the rocker
cover than a YS .53 is. What is usually not mentioned is how narrow the
crankcase is; this is actually even more impressive although perhaps not
as important as engine height is to those trying to cowl around one. A
lot of displacement has been squeezed into relatively small package.
All steel wearing parts are hardened and the cylinder is NicaSil
plated. The piston is nearly conventional except it has a "ring and a
half"; there is a second ring below the first compression ring although
this is listed as an oil control ring rather than a second compression
ring. The cylinder and head are quite wide making for massive cooling
area. These engines are reputed to last a long time and their design and
appearance would certainly seem to indicate this.
Unlike most current 4 cycle model engines these engines are somewhat
different regarding the valve train and valve train location, and the
carb. and muffler mounting are quite different. Rather than using
threads to hold on the exhaust nipple and muffler, Neil Tidey uses an
O-ring and clamp arrangement to secure both the carb. and muffler (there
is no header per se). This allows quick removal / installation as well
as full 360 degree positioning of each item. The muffler mounts directly
to the head and it's quite small; even considering it's size most of it
can be tucked behind the cylinder leaving very little muffler sticking
out. There is no intake pipe for the carb. either, it mounts directly
behind the head and points directly into the intake valve. A clever and
simple way to mount both devices. The entire valve train is mounted
behind the cylinder. There are two independent cams located behind the
crankshaft and these operate conventional push rods and rocker arms. One
unusual aspect is that the rockers and valves are set at quite an angle
compared to conventional model engines. This is where Lasers gain a
significant height advantage over more conventional engines; there is
more of the rocker behind the cylinder than there is above it. Further,
this layout will protect the entire valve train assembly from crash
damage; to bend a push rod or push rod sleeve one would have to actually
break the cylinder. After a crash that bad the push rod condition is
quite meaningless.
Running- The engine started readily, ran and idled well. Fuel was
K&B 500 (12 1/2% nitro, 17% synthetic oil and 1% castor oil) although
the owner usually uses 10% nitro with 15% all synthetic oil. Power
output is reasonable for a normally aspirated (non- supercharged) engine
of this displacement and weight, turning an APC 12-8 to 10,500 rpm
peaked. No difficulties, oddities or problems were noted.
Overall, a high quality, well made engine. About average in weight
but short and wide for it's displacement. Noise output seemed about
average although I did not measure it.
OPINION: The following is my take on these engines. Or, this is the
part that should generate the most flames :-)
It would not be a mistake to buy one of these engines and I can't
imagine anyone happy with any conventional, normally aspirated 4 cycle
model engine wouldn't be quite pleased with one of these. They are
better made than the average Japanese 4 cycle and use superior materials
(hardened valve train components, cylinder lining, ring(s), etc.).
The upside: These engines are short and have narrow crankcases for
their displacement. Fitting them into a tight cowl space, which is one
of their long suits, is where they hold their best advantage. Further,
the generous finned area would make them cool better than most Japanese
engines of similar displacement. Laser engines become something of a
bargain when comparing their twins to Japanese twins. All Laser engines
currently made are "V" twins and they cover quite a range; from 1.60 to
3.0 cu. in. displacement. While the price increases substantially, it
does not jump into the ridiculous territory that Japanese multis seem
to.
The downside: there are two basic problems. 1) Lasers actually offer
little over conventional Japanese engines other than simply being made
of better materials. As the Japanese engines seem to last for years and
years, one has to wonder how much of an advantage this is. Put another
way: this engine may well fix several problems that no one has. 2) In
the US, the single cylinder engines are rather expensive compared with
Japanese engines of similar displacement and power output. In the UK,
Japanese engines cost so much that Lasers are actually competitive price
wise and therefore a good value; here this is not the case. A Laser 70
is £200 ; at current exchange rates, this calculates to $300. An OS .70
is readily available for less than $200 and compares will with a Laser
70 overall, and for $215 a Saito .91 can be purchased which is both
lighter and more powerful.
For specifications, prices and photographs, the link is:
http://www.laserengines.com/index.htm
Brian
"You can always tell an Engineer....
But you can't tell him much."
David Larkin
I was hoping you would comment on Jim's engine and find your comments
interesting.
Perhaps there are some more comments that can fairly be made:
The LASERs are designed for sport and scale use and consequently perform
reliably in cowlings, and in different mounting positions - there is no
need to add a nicad if you mount your engine inverted! The fact that
LASERs are so user friendly is not insignificant. Pleasure of ownership
and operation is important. The fact that LASERs are overwhelmingly the
most successful engine for FAI R/C Scale use says something for their
reliability and dependability in this type of application.
Within the single cylinder LASER range there are differences of approach.
Some are designed with particular emphasis on power, others have been
designed more with compactness in mind, than specific power.
I think if you had actually made noise measurements you would have found a
significant difference between the LASER and other four strokes. I have
difficulty hearing my LASER 80 if several planes are flying.
While LASERs are expensive, I see a number of repeat orders from LASER
users. Consequently I infer that their owners are happy with the value
offerred.
Best regards
Dave Larkin
Cregger
centerline must be within 3/8" of the carburetor's spraybar, how would this
affect fuel tank installation in "normal" model airplanes? Especially with
inverted engines.
--
Ed Cregger
ecre...@mindspring.com
Brian D. Felice <bdfe...@flash.net> wrote
> I thought I'd write a short review of the very first Laser engine
> that I've seen 'in the flesh'. (snip)
Chris Hinds
Important point though. The Laser 70 also spins 12x8@10500rpm using 0%
Nitro (but only on 15% oil, if you add more they tend to slow a fair bit -
20% makes them run really badly especially those over 1cu.in). Sorry
couldn't let that one pass :)
Relatively the Laser is far easier to handle at least on the designed fuel
(unsure about how they handle on Nitro), in that I have never had a kick
back from any of my friend's Lasers (damn - must get one). These include a
70, 80, 150 and a 100 and soon a 200V-Twin.
Laser also can be made to idle incredibly low. I think I got the 150 down
to a flight idle of 1500rpm on straight fuel. For some reason my pal wasn't
happy flying with a 1300rpm idle :)
Regards
Chris
Brian D. Felice <bdfe...@flash.net> wrote in message
news:39303DBC...@flash.net...
Jim Archer
efficiently than most four strokes. The only time I've ever had the
slightest problem was with an old (1964) Laser 61 mounted upright in an old
Lou Andrews Aeromaster. The guy who built this mounted the tank very low,
leaving a distance of aver an inch between the _TOP_ of the tank and the
spraybar. This model does tend to load up a bit during _prolonged_ inverted
flight.
Most Lasers that I have seen are mounted inverted.
--
Best regards
Jim (night owl) Archer, Norwich, UK
http://www.jimarcher.cwc.net
Cregger <ecre...@mindspring.com> wrote in message
news:8gq0vf$gic$1...@slb7.atl.mindspring.net...
> Since I abide by the rule that says that the level of the fuel tank
> centerline must be within 3/8" of the carburetor's spraybar, how would
this
> affect fuel tank installation in "normal" model airplanes? Especially with
> inverted engines.
> --
> Ed Cregger
> ecre...@mindspring.com
>
>
>
> Brian D. Felice <bdfe...@flash.net> wrote
>
> > I thought I'd write a short review of the very first Laser engine
> > that I've seen 'in the flesh'. (snip)
>
>
>
Brian D. Felice
Yes, I know the Laser is cut to use zero nitro fuel and have no doubt that
it does this with ease. I did forget to mention this but also feel that it's
virtually insignificant in the states (US) anyway as we usually use either 10%
or 15% fuel anyway. I've never even seen no-nitro fuel for sale here locally
although it is available mail order. Bear in mind that I wrote that from the
point of view of the American modeler and no-nitro fuel isn't a significant goal
here.
I saw Jim start the Laser one time by hand and it certainly started readily
on the 'backflip' but then again, so do most Japanese engines. There did not
seem to be a significant difference in it's behavior when compared to other 4
cycles of it's displacement.
The only engines that have truly impressed me with low idle have been OS
.70's and .91's. They will continue to idle at speeds that should have shut them
down handily. The Laser had a fine low end that was absolutely reliable and more
than acceptably low but not in the best OS class.
I only saw this engine in action a handful of times and do not own one; I
would certainly not consider myself a Laser guru. It may well have subtle
attributes that escaped me. Also, I tend to compare all 4 cycles with regard to
OS engines because they are so common here and they are extremely conventional-
it's easiest for me to think of other engines as to how they deviate from OSs.
Rgds,
Brian
"You can always tell an Engineer....
But you can't tell him much."
Brian D. Felice
Yes, it's clear that Lasers have a good and loyal owner base. Clearly
different than, for example, MDS :-) Lasers have been around long enough to
know that this loyalty is not the result of three good engines. If I were to
buy one, I would also fully expect that any major flaws that occurred during
manufacturing had been sorted out at the factory. Mass production will always
yield a few badly flawed examples no matter how good QC (QA to the younger
people) is. Neil gets around this by simply running each and every engine that
he makes and that alone would be worth something to the person starting a
brand new 'brand X' engine only to find that it had a broken ring.
You may be entirely correct about the noise output. I did not measure it
nor were there any other 4 cycles around to compare it with other than my YS.
It was significantly quieter than the YS but this is to be expected due to
turning slower, using less nitro and being a smaller engine. Certainly it was
not any louder than, say, an OS .70 although the exhaust system is both
smaller and lighter. I know the recommended BMFA noise levels are very low and
these engines seem to have no difficulty meeting them.
Brian
"You can always tell an Engineer....
But you can't tell him much."
Brian D. Felice
The example I saw (Jim's 70 in a AcroWot) was side mounted and presented no
problem. I don't know if you could center the spray bar to the C/L of the tank
should the engine be mounted upright or inverted. I also don't know how much of
a problem it would be to offset the spray bar to C/L by, say, 1/2 to 5/8 of an
inch though; it may not be a significant problem. These engines typically don't
use muffler pressure so I assume they have a reasonably sized venturi in the
carb. in the first place. Any tank placement problems are aggravated by the now
common practice to use a very large carb. throat for a given engine size.
Brian
"You can always tell an Engineer....
But you can't tell him much."
David Larkin
Aldrich visited the factory and was shown around. He was impressed. Afterwards
he was chatting with Neil and said that while he reallly liked the engines he
wasn't in the market for one just then - but could he have a reject part as a
souvenir? This caused a pained expression to pas over Neil's face "Actually,
George, we don't make any reject parts." However he gave George a valve cover to
take home.
Also Neil keeps very close tabs on the behaviour of his product. It's a habit of
his, I'm told, to ask club members if they would mind if he unbolted their
engine and took it back for stripping and examination. This way he can see how
everything is standing up under field conditions. Improvements are fed in to
the production progressively as they are developed, like the switch to ABN and
the switch from Supertigre to Irvine carbs. So if you are buying engines for a
twin it is best to buy a pair to the same spec. I bought two LASER 50s some
months apart and ended up with one standard and one ABN engine, though Neil says
they have close enough the same power output.
"Brian D. Felice" wrote:
> Dave,
>
> Yes, it's clear that Lasers have a good and loyal owner base. Clearly
> different than, for example, MDS :-) Lasers have been around long enough to
> know that this loyalty is not the result of three good engines. If I were to
> buy one, I would also fully expect that any major flaws that occurred during
> manufacturing had been sorted out at the factory. Mass production will always
> yield a few badly flawed examples no matter how good QC (QA to the younger
> people) is. Neil gets around this by simply running each and every engine that
> he makes and that alone would be worth something to the person starting a
> brand new 'brand X' engine only to find that it had a broken ring.
>
> You may be entirely correct about the noise output. I did not measure it
> nor were there any other 4 cycles around to compare it with other than my YS.
> It was significantly quieter than the YS but this is to be expected due to
> turning slower, using less nitro and being a smaller engine. Certainly it was
> not any louder than, say, an OS .70 although the exhaust system is both
> smaller and lighter. I know the recommended BMFA noise levels are very low and
> these engines seem to have no difficulty meeting them.
>
> Brian
>
> "You can always tell an Engineer....
>
> But you can't tell him much."
>
Lyman Slack
Great review and I have to say I concur 100% -- I'm running one in
my "Custom Live Wire" (Built for a recent Vintage R/C event from 1958
plans). Great engine as far as I'm concerned; I also have a 1.20 waiting to
fit into the very small cowl of the TF Bonanza currently on my bench.
Take a peak at the model in the "Hanger" section of my site
http://fdt.net/~lyslack/
One great point: The manuals for all the Laser line are shown on
their Web Site.
Cheers -- \_________Lyman Slack__________/
\_______AMA6430 IMAA1564___/
\_____Flying Gators R/C_____/
\___Gainesville FL________/
Brian D. Felice <bdfe...@flash.net> wrote in message
news:39303DBC...@flash.net...
David Larkin
I feel should always be brought to a prospective owner's attention. The LASER
instructions suggest that you place the tank in the usual location relative to
the spraybar in an aircraft intended primarily for aerobatics, but that a
departure from optimum location is acceptable. Bear in mind that the LASER
has very good fuel economy so the tank size required is quite small, and that
two seperate tanks are used for the twins. Usually optimum tank location
isn't a problem for inverted or side-mounted engines unless you have committed
yourself to a forward servo mounting location or something like that. It
would be more of a problem with an upright engine, but upright engines are a
relative rarity in fully aerobatic designs.
LASERs have good fuel draw, do not use muffler pressure but benefit from a
little extra pressure provided by facing the vent line into the propwash.,
Cregger wrote:
> Since I abide by the rule that says that the level of the fuel tank
> centerline must be within 3/8" of the carburetor's spraybar, how would this
> affect fuel tank installation in "normal" model airplanes? Especially with
> inverted engines.
> --
> Ed Cregger
> ecre...@mindspring.com
>
> Brian D. Felice <bdfe...@flash.net> wrote
>
> > I thought I'd write a short review of the very first Laser engine
> > that I've seen 'in the flesh'. (snip)
WFTEX
Ken
David Larkin
is just to ensure that the pressure at the vent is positive and there is no
suction.
James G. Branaum
muffler to put a tap on.
Jim Branaum j...@flash.net AMA 1428
"Another modeler supplying glue to the AMA"
"WFTEX" <wf...@aol.com> wrote in message
news:20000528201105...@ng-bg1.aol.com...
Richard Crapp
my tank vents for the twin tanks down in the bottom of the cowl with no
ill effects. The 300 V is upright in the WACO and has 7" extensions to
the exhaust. doz. 8.400 on the 20 x 8 Bolly. STRAIGHT fuel. BTW.
In article <GDnY4.192$IO4....@news.flash.net>, James G. Branaum
<j...@flash.net> writes
--
Richard Crapp