Laser Engines - Technical questions

[John Rickett 102]

Artto,

 

If you don't know anyone handy with a lathe, you could ask Just Engines to make you a shaft extender, with the hex end substituted for a Gipsy Major spinner shape. They are happy to undertakes one-offs and at reasonable prices.

  

https://www.justengines.co.uk/?s=shaft+extender&post_type=product&v=79cba1185463

 

[Chris Walby]

Odd colour for a steel adaptor 🤣 Worth remembering that Jon does not advise weighted spinner or heavy lumps on the end of the crankshaft although an adaptor would be ok I suspect.

 

Almost every electric model I have has either aluminum dome nuts or back plates etc plus IC aluminum backplates, cones or domed nuts and can't say I have had any issues (apart from the exploding plastic ones!). As I said only issue is the wooden props hubs compressing and needing nipping up every now and then.   

 

 

[Artto Ilmanen]

On 23/09/2021 at 17:09, Jon - Laser Engines said:

5/15x24 unf or m8x1.25 depending on age. My bet would be m8 if the 10 years is accurate

 

Sorry Jon - I believe there is a typo here and you meant 5/16x unf? ( as we spoke on the phone?)

 

 

 

 

[GrumpyGnome]

On 10/03/2023 at 17:40, John Rickett 102 said:

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. 

 

I'd need three hands for that....

[Jon H]

On 12/03/2023 at 08:13, Artto Ilmanen said:

 

Sorry Jon - I believe there is a typo here and you meant 5/16x unf? ( as we spoke on the phone?)

 

 

 

 

 

yep, 5/16. Too quick on the buttons. 

 

On 10/03/2023 at 21:50, Chris Walby said:

Jon does not advise weighted spinner or heavy lumps on the end of the crankshaft

 

This is mostly when an issue when people try filling a spinner with lead or hanging a 2lb lump on it. A big ali spinner or small adaptor thing is going to be fine. 

[John Rickett 102]

On 12/03/2023 at 09:52, GrumpyGnome said:

 

I'd need three hands for that....

 

I’ve found that while Lasers are quite benign, the 180 is the one most likely to kick back when starting, this can either loosen the prop nut or throw the prop altogether. Having had a thrown prop damage a model, and the prop, on more than one occasion as well as having to search for the washer and nut, I thought there had to be a better way.  

As with most problems there is usually more than one solution to spinning the engine prior to applying the glow.  The easiest is enlisting the assistance of a helper, however if (like me) you are often Billy No-mates, adapting the power source to automatically provide the delay is an alternative.

 

 

For a number of years, I’ve preferred using a power panel as it allows for the current draw to be seen and adjusted for various plugs. One of these little timer modules can be bought for about £5 and has the ability to alter both the timing of the delay and the ‘on’ period from 0.1 sec to 99.9 seconds, which should cover most people’s requirements.

 

 

I've set the delay before ‘on’ at three seconds, this gives time to pick up the starter and spin the engine, after which the glow comes on for 10 seconds. If the engine doesn’t fire up in 10 seconds then something is wrong, but a press again of the START switch initiates the sequence again.

In addition to the timer module itself, all that is needed is a monetary switch to trigger the timing. I wanted the ability to bypass the timer and use the ammeter and rheostat to initially set the required current draw, so installed an additional switch to put the timer in or out of the circuit as required.

 

 

My starter box is a bit Heath Robinson as I already had the panel and a 3300mAH 12v battery so just fitted the bits in the unused space, nevertheless it works and enables me to start a glow engine unassisted and without fearing a kick-back.     

Edited March 13, 2023 by John Rickett 102

[Paul De Tourtoulon]

Seems very complicated, I got a Saito 100 second hand that threw props, even when taxed out to the runway when opening her up, I shimmed the engine cylinder

0.2 mm that did the job.

 

 Opps I forgot I also shimmed my Enya 120 4c with 0.4,,,

Edited March 13, 2023 by Paul De Tourtoulon
opps

[Jon H]

I have to confess i have never had a laser throw a prop at startup unless something was wrong with its spinner. My P39 did it twice before i discovered the prop was bearing on the smooth ali backplate of the spinner rather than the knurled part. This was because the wood prop was used on another model before and the hub was compressed in the middle. Once i figured that out it was never an issue. My little Hurricane did something similar as the nylon prop didnt stick well to the nylon spinner backplate. A layer of folded over 400 grit paper soon solved both problems. 

 

 

 

 

 

[GrumpyGnome]

4 hours ago, John Rickett 102 said:

 

I’ve found that while Lasers are quite benign, the 180 is the one most likely to kick back when starting, this can either loosen the prop nut or throw the prop altogether. Having had a thrown prop damage a model, and the prop, on more than one occasion as well as having to search for the washer and nut, I thought there had to be a better way.  

As with most problems there is usually more than one solution to spinning the engine prior to applying the glow.  The easiest is enlisting the assistance of a helper, however if (like me) you are often Billy No-mates, adapting the power source to automatically provide the delay is an alternative.

 

 

For a number of years, I’ve preferred using a power panel as it allows for the current draw to be seen and adjusted for various plugs. One of these little timer modules can be bought for about £5 and has the ability to alter both the timing of the delay and the ‘on’ period from 0.1 sec to 99.9 seconds, which should cover most people’s requirements.

 

 

I've set the delay before ‘on’ at three seconds, this gives time to pick up the starter and spin the engine, after which the glow comes on for 10 seconds. If the engine doesn’t fire up in 10 seconds then something is wrong, but a press again of the START switch initiates the sequence again.

In addition to the timer module itself, all that is needed is a monetary switch to trigger the timing. I wanted the ability to bypass the timer and use the ammeter and rheostat to initially set the required current draw, so installed an additional switch to put the timer in or out of the circuit as required.

 

 

My starter box is a bit Heath Robinson as I already had the panel and a 3300mAH 12v battery so just fitted the bits in the unused space, nevertheless it works and enables me to start a glow engine unassisted and without fearing a kick-back.     

 

Hmmmmm.  I can do that with my EdgeTX equipped tranny and on-board glow...... maybe I'll give it a go!

 

[Chris Walby]

Not wanting to be too controversial, but the only time I have had a Laser fire backwards was because I was not following the correct starting procedure.....

 

I'll go an sit on the naughty step now. 🤣 

[Paul De Tourtoulon]

55 minutes ago, Chris Walby said:

Not wanting to be too controversial, but the only time I have had a Laser fire backwards was because I was not following the correct starting procedure.....

 

I'll go an sit on the naughty step now. 🤣 

So what's so different ?.

[Paul De Tourtoulon]

Fiddling with my second hand 'vintage' OS .80 fs in my Skyraider, what sort of rpm would a laser .80 give you on the ground with a Graupner 12 x 7 prop and 10% nitro ?.

[Jon H]

2 hours ago, Paul De Tourtoulon said:

Fiddling with my second hand 'vintage' OS .80 fs in my Skyraider, what sort of rpm would a laser .80 give you on the ground with a Graupner 12 x 7 prop and 10% nitro ?.

 

No idea, never run a prop that small and i wouldnt recommend a prop smaller than 14x6 for an 80. APC 14x6's do about 9-9200

 

Why is your OS running such a tiny prop? it must be revving its rod off 

[Paul De Tourtoulon]

13 x 6 apc at 9.100rpm and the same rpm with the 12 x 7 Graupner.

 

 My Skyraider was hanging on the 13 x 6 prop and as I throttled it down to see how stable it went into a wicked spin, next job

sort out a 13 x 7 / 13 x 8 /12 x 8

Edited March 18, 2023 by Paul De Tourtoulon
props

[Jon H]

1 hour ago, Paul De Tourtoulon said:

13 x 6 apc at 9.100rpm and the same rpm with the 12 x 7 Graupner.

 

Ouch. I expect between 10200 and 10500 on a 13x6 apc, and that is on 5% nitro. 

 

I wouldnt expect an OS80 to be that far behind. Which version of the engine have you got?

[Paul De Tourtoulon]

I don't know which version it is as I can't find much information on the .80's,  I also have one in my Hurricane, as it is Sunday I will spare my neighbors, so tomorrow I will see what that one is giving and what Apc prop it is turning and then swap the prop to the Skyraidrer, I have half a dozen different props to play with.

[David Ovenden]

My recollection us that the OS FS80 was rated at only 1.1bhp. The first version FS90 was 1.3 and the OO FS91 surpass improved that to 1.6bhp. Whilst these bhp figures don't proper idea of give real world performance, they do show that the old FS80 wasn't the most powerful engine. However, a perfectly good engine for its day. And still a useful motor now. 

[Paul De Tourtoulon]

Opps You can't see me, but I am wearing a 'Dunces' hat,,,

 

My Hurricane's OS .80 is in fact a .90🤐, a completely different engine, on the .80 it has the old .60 open rocker carb, so I won't be doing much just fiddling with different props till my Laser project gets under way to replace it.

 

 There is an American Video on it with it turning a wood 13 x 6 at 7.900rpm.

Edited March 19, 2023 by Paul De Tourtoulon
video

[Paul De Tourtoulon]

Oh dear, I see that after humans now Laser engines are being tortured,,,

There is even a video going around of the front cooling Fins being cut off like finger nails.🤢

Edited March 27, 2023 by Paul De Tourtoulon
fins instead of google translate, blades, fogotten the proper name.

[Jon H]

1 hour ago, Paul De Tourtoulon said:

Oh dear, I see that after humans now Laser engines are being tortured,,,

There is even a video going around of the front cooling Fins being cut off like finger nails.🤢

 

Yes for some reason folk feel the need to chop, cut, file and drill into their engines. I have to ask myself why. If it needed more holes drilled in it or pieces chopped off, do you not think we would do it before it left the factory? Its not like we forgot. 

[Chris Walby]

Serious Complaint

 

What's wrong with this world, there I am yesterday up at the flying field in wind and cold with my FT200. Its not been run since last year and just look at what happened!

 

All checks complete, engine primed and the darn thing starts first time and then to add insult, it didn't even need need a tweak in the main needles. just flew around sounding awesome. I even tried flying inverted and bunts, but it was having none of it and just kept running. I landed having cold fingers and it hadn't even used half a tank.

 

I gets worse as after 4 flights it was time to go home and on packing up only found two small and not even patches of wet oil on the fuz. I mean how are you meant to get all the mud off the wing when there is so little oil!

 

What was wrong with the good old days of unreliable engines, hours of freezing your fingers off trying to get it started only to quit with the nose up test or on the take off roll!

Its either therapy or start this ASP up I have and let it slobber down the fuz with the smell of castor in the air. With the age old question...when is it going to dead stick on me!

 

Rant over 🤣

 

[Don Fry]

Got an old Laser 150, BA bolts, silencer with a single o ring. O ring is worn, not gas tight.

What size are they?

sorry re English, left I pad on car roof, using the phone.

[Jon H]

They are BS012 Don. If you cant find any send me an sae with a few quids worth of stamps to cover the payment and i will send some back to you. Its not worth putting it on a card

[Mike Mc]

Laser 70 Prop

 

I finally got my new Laser 70 flying on a 10cc size Ultra Stick. It has more power than I expected, perfect for sport flying. I am running an APC 13x6, the flight performance is excellent, but it turns 10,100+ peak, fly at about 9,900. Is that too much RPM? Should I get a 13x7?

 

.

 

Edited April 8, 2023 by Mike Mc

[Paul De Tourtoulon]

Sorry to hear about your bad day Chris, an Asp, Mds would probably have been more fun, or like our regular plane crasher,

he has his Seagull D 520 with an inverted Super Tiger, running a Kavan 4 stroke plug and the bottom of the fuel tank 2 +cm above the needle valve, and all I hear is the carb leaks, it won't start or when he eventually gets it in the air it's the usual dead stick into the fields with the UC down and hanging on by its wires,,,😅