AeroFinn

Yup Menz 20x8 is probably the best overall prop for the 300v (I haven't tested the CF props) I'm hoping the APC narrow blade prop pulls less than the Menz at idle so the model slows down for landing better. That's why I'm trying the Apc. But I guess I need to grab a Menz 20x8 to make side by side comparison.
I also anticipated to get lower idle with the Apc due to more mass but this isn't the case as I need to richen the LS needles more than with wooden prop

Carosel43

The 300v on my la7 will idle about 1500 or so. That's plenty slow enough and I have no issues with response. As I said before, 7300-7600 rpm is typical depending on the day

AeroFinn

I won't be making it too complicated. So in case if I'm not happy with response with the Apc 20x8 I'll just go for the Menz 20x8
Thanks

Telemaster Sales UK

I planned to fly at England's greatest Fly-In at the Greenacres Club near Walsall in the West Midlands which was held on 21st and 22nd June. I could not test-fly the models I had built for the event in time, but I had another model, a Senior Telemaster,(STM). I'd always had a soft spot for the Telemaster since passing my A Certificate on a Telemaster 66 powered by a Merco 35. The Senior Telemaster however, is a big eight-foot trainer, which was the flagship of my fleet when I used to import the Telemaster range into the UK from America; it is powered by a Thunder Tiger 91 fourstroke but I had run the bearings on this engine through not using after-run oil. No problem I had another identical engine so it was only a question of swapping the engines over wasn't it?

Now dear reader, read on...

Having given up on the Foam-E WOT 4, the Acrowot and the Baby Barnstormer, I dragged the dusty "well-flown" STM out of its retirement in the loft. (Note for novices, the term "well-flown" in aeromodelling parlance means extremely scruffy!) The engine was bolted to a Du-Bro Quiet Mount. I had two options:

1. Remove or drill through the balsa block underneath the engine to get access to the nuts or...
2. Find my long Allen Keys and remove the whole mount.

I decided on the second option. The assembly came out quite quickly, undo four nut and bolts, engine's free, go upstairs to the engine stash, get spare Thunder Tiger, bolt to mount, fit mount to model, connect carburetor push rod, fit propeller, fit spinner, fit exhaust... funny, it doesn't seem to have much compression. Connect glow lead, apply starter motor,... whirrr,... whirr... nothing. Valve clearances! Check and adjust whirr..., whirr.... Nothing! Off with spinner, prop and throttle push-rod, Allan keys out, mount off, undo four nuts and bolts, back upstairs to the engine stash and consider options.


I had five.

1. Fit an OS FL 70.
2. Fit a Laser 70.
3. Fit a Laser 91.
4. Fit a much loved OS 61SF two-stroke. If I could only have one engine, it would be this one.
5. Give up!

As we have just celebrated D-Day giving up wasn't an option. The Du-Bro mount was duly refitted finger tight and the remaining engines were offered up. The 70s were a bit too narrow besides I had flown an STM fitted with an OS 61 fourstroke and it barely flew it. It was quite dangerous on take off. I thought that the model might be a bit underpowered fitted with either 70 so they were rejected.


The Laser 91 fitted but the silencer fouled the rubber mount so I could not get it far enough back in the mount for me to be able to drill the forward mounting holes. The OS 61 SF fitted but I would have to cut away the nose block to allow for the silencer and main needle. I didn't want to do this but didn't I have a brand new nylon mount for a 91 fourstroke up in the loft?


Mount retrieved and drilled to suit Laser 91, Du-Bro mount removed, four new holes drilled into firewall, find four socket bolts and nuts, bolt mount to firewall, find four suitable self tappers, mount engine, drill another new hole in the firewall for the new throttle pushrod, attach to throttle servo, propeller fouls nose! Fit a spinner with the back plate behind the prop. Propeller clears!


It doesn't sound much does it, but I was working on this model until 10pm and I still had to fit a remote glow connector as the glow plug faces forwards on this engine. Having done that the engine was fired up the following morning. All good so its off to the local club's flying field for a test flight which went well.

There were hundreds at the event but and if there had been a prize for the scruffiest model there it would have won! I flew the model around a number of shakey left-hand circuits in a cross wind but nothing which the old STM couldn't handle with the Laser performing heroically chuffing smoke over the top of the wing! It ticked over like a Swiss watch as it landed and I taxied it back to the starting box.

One up for British engineering!

Telemaster Sales UK

Here is the old thing!

Carosel43

looking good, what prop are you turning?

Telemaster Sales UK

14x6.

Telemaster Sales UK

Further to my post about the Greenacres Fly-In, I saw a 1/4 scale Bristol Monoplane there powered by a Laser 180. It sounded fabulous. Mind you so did an Evolution radial in a Bucker Jungmann.

AeroFinn

Hello guys,

I'v now been flying my Great Planes Yak 54 with a Laser 300v-twin on it for about 2-3 hours

weight: 7,3 kg or 16+ lbs + fuel (2 x 300ml)
fuel: 5% nitro + 17% Aerosave full synthetic oil + rest methanol
max rpm: 8200 + with APC 20x8 or maybe a bit more now, I haven't checked the peak rpm lately.

This model is a joy to fly and operate! The engine has been very reliable: I haven't lost even a pot in flight!
The vertical performance is unlimited, even if the engine tune is slightly on a rich side. Therefore sequence flying is very easy as you have power in reserve to compensate wind, etc. (I don't fly 3D)

I'v paid attention to proper cooling arrangement (see pictures) as the engine is completely hidden inside the cowling.

-Artto

Hobbsy

My Feedback: (102)

Ernie, this was my first LASER, a 1.80 V-twin, it would howl like a 283 Chevy at full blatt with a Graupner 16x8. Here are some numbers for my LASER .70
I ran the Laser .70 today sporting new Boca bearings with ceramic balls running in stainless steel races.
Fuel WildCat 5% nitro/16% 80/20 lube.
Plug==Fox Miracle
Prop==APC 12x7
Peak rpm 10,500

Telemaster Sales UK

Got my old 150 V twin running in the back garden. It produces a hell of a waft! One cylinder seems to have greater compression than the other mind.

Telemaster Sales UK

Flashed up my Laser 70 in the back garden yesterday. It was too windy for flying.



I'm going to fit it it into this model, an Acrowot, once I've repaired it! These are very popular in the UK.

Telemaster Sales UK

I see that the Saito enthusiasts and the owners of BUSA modes have formed "brotherhoods" with every member being allocated a membership number. Is there any interest among Laser enthusiasts for a similar arrangement or are we too sophisticated for that?

If there is any interest, I propose that the brotherhood be called "The Laser Owners Brotherhood International" or LOBI for short and I nominate Carosel43 as Brother No 1!

Merry Christmas fellow Laser enthusiasts and a Happy and Prosperous New Year from me!

Carosel43

Oh no I have been nominated for something! does it mean I need to do any more work?

The acrowot will be cracking with the 70 though. I think a 12x7 will be a good bet.


Oh, and I am very impressed with your super technical engine storage tree stump

Telemaster Sales UK

No you just have to accept the title "LOBI Brother No 1." I'm quite happy to compile and maintain the list if there is any interest, and to be LOBI Brother No 2!

I thought of calling the brotherhood the "International Laser Owners' Brotherhood" but the acronym would be ILOB and you don't have to do that with an engine as powerful and reliable as a Laser!

As for the tree stump every Englishman should have one! They're ideal for storing engines as you saw.

A few weeks ago I bought two secondhand engines, an old Meteor 60 and an OS 48 Surpass for £28 from my local model shop. The OS required a new carburettor but as it was too windy to fly, I spent last Sunday afternoon running up some old friends. As well as the Surpass, the Meteor and the Laser, I also ran a Super Tigre 40, an OS 61SF and a baby HP VT 25. Good fun!

WhiteRook

My Feedback: (38)

what size laser engine would i need for a 26 to 30 pound warbird with a 88 inch span?

Hobbsy

My Feedback: (102)

Whoa Tel, maybe I should be LOBI's first member, I started this thread on 3/3/2007.

Telemaster Sales UK

White Rook, an 80" Lavochkin flies with a 300 Laser V Twin. A 360 (60cc) is available if you feel you feel the need for extra power. http://www.laserengines.com/product-...inder-engines/

Hobbsy, if you want to start LOBI be my guest.

WhiteRook

My Feedback: (38)

mabey i can find a 300 used , awfull pricey new, thanks
it would be a really good fit on my bates tempest , short nosed like it is.

AeroFinn

I think you'd better go for a 360v. Check carousel43's youtube video on La 7 w/ 300v for reference. The model weighs about 18-19 pounds I believe.

CH Ignitions

My Feedback: (11)

Hi Guys , I finally had a chance to play more with this very long project.
I had quite of bit of challenge to determine and machine the parts to fit right.
I am not quite sure if this is something that I will market...But it can be done.
That is first reason that kept me going and going after several miserable failures in the row.
Enjoy it as much I "hate it to do it"....LOL

Thanks
Adrian

https://www.youtube.com/watch?v=3H5Alwq137g

Carosel43

very interesting video Adrian. You have great pickup and im guessing quite a small venturi carb with acceleration pump? It seems to be hurting the top end performance as I would normally expect 7400rpm on 20x8 menz prop. In my own work on this I have found there is a very difficult balance to be had between the top end power and acceleration/midrange and carb sizes are critical.

Im not sure if anyone has seen this but this is the Laser factory works prototype of the Laser 180. In the video it is running an apc 17x8 and is being setup for new fuel. It will also take 18x8 to approx. 7400rpm, 19x8 approx. 6700rpm, 20x8 approx. 6300rpm and 22x8 approx. 5200rpm.

See what you think

https://www.youtube.com/watch?v=k1Tg9rYacDk

Telemaster Sales UK

It looks alright to me!

AeroFinn

Hi Adrian

Very interesting! Thanks for the video. As a reference, last time I flew my 300v with a Mejzlik 20X8 prop I got 7700rpm. This was in a cold weather (-5deg celsius) and the fuel was 5% nitro and 15% Aerosave. I normally get about 300+rpm in the summer. In summer my 240v runs 8400rpm with 18X8 Menz and 8200 with 18x10 APC. This is with 5% nitro, too.

Adrian, did you try to run the engine with dual carbs?

In another forum Gordon W reported having run the 300V on gas/ petrol fuel with original carbs + cline fuel regulators and a perry pump. He said the max rpm with a Mejzlik 20x8 was 7900. He had some issues with the reliability, though. This was probably due to the original glow carbs not being suitable for gas / petrol.

Carousel 43: Thanks for the link. As I said in another forum, this is very nice. Any news on the topic?

-Artto

CH Ignitions

My Feedback: (11)

Hi Guys, sorry for the delay, I did not got the replay notification... Thanks Jon for letting me know.
I will need to buy a Mejzlik 20X8 prop so we can compare apple to apple and I will try to see if
I can get the 7400 RPM range.
I will try to play with more carbs...I have quite of bit. The venturi on this is 9.5mm . I will tried and I will try couple of bigger venturi . Another thing I will Mod this Carb,
I will increase the venturi in steps. At one point I will loose it. so I need to find that point.
Thing is my time is limited and have to build ignitions , I have bunch of engines in line for fix/convert from customers.
I make everything from A to Z and have a full time job also. Maybe in couple years...this will make enough and I will do only this.
My wife helps a lot, she solder the PCB for ignitions and I tune them, box and test.
The 2 tubes that connects the manifold have a 8.5mm ID and that I think is fine, the 2 piece"*******" manifold is V5 si I made 4 previous .
I run it with regular carbs with gas but...it was so long ago and I do not quite remember the RPMs...but I remember that was a bear to set them up and
will be so sensitive to tank position.
I wanted to make it with 2 carbs....but then will be double trouble, more weight and then double tuning, linkage in between and the angles of this engine...
is not quite user friendly. That is why I wanted to go with single carb. The self pump issue I solved it by using the crank pulse, from the intake as I usually do
was not enough for WOT, It will die/starve.
What else....here is a picture of the "*******" that eat me alive until I got it to fit where I want it and how I want it.
Like I said...I will continue with development and hope for a 7400 RPM. The gentleman that loan me this engine told me that I can keep it longer.

The parts are for view ONLY !

Thank you guys

Adrian