By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

Laser Engines - Technical questions

All Topics | Latest Posts

Search for:  in Thread Title in  
Andy Stephenson29/11/2020 22:58:47
avatar
353 forum posts
46 photos

Guys,

I have had it hotter than hell using a paint stripper gun and I've tried all the other stuff and more.

My DIY hub puller just bends after cranking the thrust bolt to the max. I will have to find a way to reinforce it.

A.

Piers Bowlan30/11/2020 05:10:42
avatar
2351 forum posts
68 photos

Andy, I am no engine man but have you tried immersing the engine for several hours in glow fuel or any other solvent to soften the baked goo?

J D 830/11/2020 08:34:21
avatar
1769 forum posts
88 photos

It does sound like you need more of a man of a puller, that and some heat with puller on. Ron's tap method also works.

Martin McIntosh30/11/2020 09:35:57
avatar
3714 forum posts
1295 photos

Never needed to strip a Laser but have done many others with the same problem. Often, a heat gun is not enough and they require rather more which means a blow torch. I do not possess a puller but a good smack on the prop nut(s) with a hammer usually does the trick as long as the prop driver is hot enough. Constant pressure from a puller is unlikely to be effective.

Jon - Laser Engines30/11/2020 11:15:24
5758 forum posts
275 photos

You either need a beefier puller or a press. I use a press here as its the only chance i have on some of the older engines where the thing has been together for 20 years or whatever. Some of them take an astonishing amount of pressure to get them out. Heating it up wont really do much to help in this instance.

Andy Stephenson30/11/2020 13:29:27
avatar
353 forum posts
46 photos

Finally success, I ventured out to get the parts I needed to beef-up my puller and with the front housing back in the puller, with no heat this time, I cranked up the thrust bolt with as much force as I could muster and it finally came off with an explosive crack and the taper collet shot off like a bullet. I have measured up all the bearings and ordered a set of 3. Now to clean up all the gunk which has accumulated and been cooked on. The liner still looks in perfect condition which was a concern until it was apart.

Andy.

J D 830/11/2020 13:40:35
avatar
1769 forum posts
88 photos

Well done. Cant beat a bit of beef.yes

Paul james 830/11/2020 13:55:35
avatar
186 forum posts
48 photos

If using the puller often as not once you have a bit of tension wound on you can shift the offending part by giving the puller a sharp tap with a hammer.

As for cleaning I always use boiling water and aerial biological washing powder, cleans them up a treat.

Any light surface corrosion or tarnishing I get off with scotchbrite.

Andy Stephenson30/11/2020 14:55:37
avatar
353 forum posts
46 photos

Jon,

I have now stripped the entire engine down but in the process of re-bedding in the valves I have discovered that both springs had broken about, 1 1/2 turns off the end of each, can I buy replacements direct from you, and it wouldn't hurt to have some split collets, I haven't lost one yet but there's always the risk when refitting them by hand.

Thanks,

Andy.

Ron Gray30/11/2020 15:23:37
2533 forum posts
1013 photos

Difficult to do at first but when messing around with those fiddly collets stick the whole thing (including your hands) inside a clear plastic bag and do the work in there!

Jon - Laser Engines30/11/2020 15:43:47
5758 forum posts
275 photos

Andy, give me a call when you can and we can sort it out. Springs are readily available as are collets should you loose one.

Andy Stephenson30/11/2020 17:31:03
avatar
353 forum posts
46 photos

Ron,

I tried that trick when I first de-coked a Laser but it just steamed up and I couldn't see anything.

Jon,

I'll call you tomorrow to arrange the parts I need.

Andy.

Maurice Dyer19/12/2020 14:49:57
173 forum posts

Just a thought, I want to buy A LASER 70, but if I mount it upright, isnt the carb fuel inlet to high for the fuel level ?

Conversely will it flood if I invert the engine, Its going in a Panic

??

Maurice

Edited By Martin Harris on 19/12/2020 17:45:33

Anthony Scott 219/12/2020 15:04:56
118 forum posts
9 photos

A common conundrum, easy answer side mount it.

Tony

Edited By Martin Harris on 19/12/2020 17:46:04

Martin Harris - Moderator19/12/2020 15:16:20
avatar
Moderator
9811 forum posts
264 photos

Jon has often said that there's little or no problem lifting fuel - flooding from too high a tank is the real problem.

Edited By Martin Harris on 19/12/2020 17:46:30

Andy Stephenson19/12/2020 16:19:07
avatar
353 forum posts
46 photos

I agree mostly, I think there's too much worry about tank position. It stems from old freeflight designs with much less sophisticated engines. On another forum there was some hysteria about getting it spot-on only to read on that it was for an aerobatic design where the fuel is all over the place during manoeuvres and especially when prop hanging. If on the ground, the fuel is leaking due to the tank being high just close the throttle until needed. If it's low an extended prime may be necessary.

Edited By Martin Harris on 19/12/2020 17:46:52

Martin Harris - Moderator19/12/2020 17:53:05
avatar
Moderator
9811 forum posts
264 photos

Copied from the Laser Development thread:

Posted by Jon - Laser Engines on 19/12/2020 16:26:25:

Gents if we could keep this thread for the development stuff that would be great. We have the technical thread for these sorts of questions.

The short answer is as Martin put it. Dragging fuel up hill is not such a problem, having it force fed is.

If inverted keep the top of the tank in line with the carb. If the tank is too high fuel will drip and the engine will stop when inverted. Its not possible to tune this out, the tank placement needs to be correct for the engine to work. If upright, just dont put the tank higher than the carb and it will be fine.

In the case of the panic its engine upright and modify the top deck a bit so the tank sits in the right line between the struts. Make a fairing, some guys have made it look like a dummy canopy, and you are good to go.

Also, no, you cant use a pump, no, you cant use a cline regulator. These rarely give satisfactory results and are quite expensive. Moving the tank is free and you are fixing he actual problem rather than trying to bandage it.

Vincent Barlow21/12/2020 21:10:11
22 forum posts

I have what seems a silly question that may have been asked previously, can the carburettor and silencer be swapped around. Many Thanks

Andy Stephenson21/12/2020 21:26:46
avatar
353 forum posts
46 photos

Vincent,

Definitely not without making a lot of modifications, the intake and the exhaust are fixed in the design, although I notice on the Vee twin engines the cylinders are mirror versions of each other.

Andy.

Frank Skilbeck21/12/2020 21:36:16
avatar
4935 forum posts
114 photos
Posted by Vincent Barlow on 21/12/2020 21:10:11:

I have what seems a silly question that may have been asked previously, can the carburettor and silencer be swapped around. Many Thanks

Jon will probably chip in soon, but it maybe possible if you swap the cams over and adjust the valve timing accordingly.

All Topics | Latest Posts

Please login to post a reply.

Support Our Partners
Subscribe now
Sussex Model Centre
electricwingman 2017
CML
Slec
Sarik
Advertise With Us
Latest "For Sale" Ads
NEW POLL - has the pandemic altered your event safety perceptions?
Q: Has the covid pandemic deterred you from attending shows and events in 2021?

 No, I'll be attending just as many as I usually do
 No, but I'll choose my event with greater care
 Yes, I'll attend fewer events going forward
 Yes, I wont attend any where previously I have

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E!