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Laser 200 in line twin - retro fit


Ron Gray

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Oh yes, plan is to run the engine tomorrow. New tank fitted with dual feed clunks, one for each carb. I used a standard 3 pipe setup but changed the fill to a feed and have a filler valve in the line. Also fitted a remote glow connector for both plugs, same as I use on my V twins.

 

Rock n Roll

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Martin, your comments on cooling are correct and exactly what i am aiming for. You are also right about the gap between the cylinders being a potential hole in my plans. The problem is, its complicated enough without having to install a baffle there as well, and the carb/exhaust do block this area to some degree. I also want some flow around the exhausts to prevent the heat contaminating the nearby cylinder. This is especially true for the front exhaust as it sits quite close to the rear cylinder and i want a nice breeze through there to keep the heat away. 

 

If the testing shows we need it, i will recommend it later, but so far i have found the engine to be pretty good on the heat front and on the bench with no baffles at all i still have to try quite hard for the rear cylinder to start complaining. I am hoping that things are not as critical as i fear they could be and we can all relax a bit. Again, had i already been able to test fly my own prototype Ron would have had an easier time as i would already have some baseline experience to work from. Alas, covid. 

 

If the weather holds i hope to get mine test run at the weekend. Its been installed for weeks but too cold for me to bother running it. I need to make my cowl and baffles too, as well as try and win back the crown for 'most hacked about cowling'. Its a very prestigious prize and every test mule aircraft should strive for it. 

 

 

 

 

 

 

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And here is the video of it second run. I did the first one this morning with the cowl on but I had a problem with my remote glow so it only ran on 1 pot, mind you it still pulled 5K on just 1! After the rain stopped I took it out again with the cowl removed so that I could put 2 separate drivers on the plugs. Things to note, I need to adjust the slow running as it's still not quite right, but top end is giving me 8.2K on an APC 18x8. Ignore me kicking the wing but hang on to the end when I tweak the top end and just listen to that sound!!!!!

 

 

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Final video of ground testing. I adjusted the slow running so that ticker was smoother than yesterday then put the cowl on and ran the engine to get it nice and warm. I wanted to make sure that there was enough cooling of the engine and Jon suggested that if I ran it a full throttle for a minute or so then cut the throttle back and then wide open agin, if it responds to the throttle then it should be ok. I'm still waiting for YouTube to process the vid into a 4K one but its taken hours so I've posted it in SD, come back tomorrow and it may then be in glorious 4K!

 

 

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1 hour ago, Low pass Pete said:

Can I ask what connectors do you use for remote glow connection at the plugs please.  All the commercial ones I can find do not stay connected on my Laser 155.

I used to use the ones from South Herts Models, brass tube with ball bearing surrounded with wire coil, but as they’re no longer available I use these Fastrax . However whilst they stay in place and are fine, they are a little bit too long so I’m going to try these Traxxas. The problem I’ve found with this engine is that due to the anodising I can’t get a good connection so my ‘usual’ setup for twins, one remote plug connected to both glow plugs, just doesn’t provide enough current, hence why when I first ran the in-line it only fired up on one. So now I have 2 separate remote plugs, one for each.

 

Edited by Ron Gray
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1 hour ago, Ron Gray said:

I used to use the ones from South Herts Models, brass tube with ball bearing surrounded with wire coil, but as they’re no longer available I use these Fastrax . However whilst they stay in place and are fine, they are a little bit too long so I’m going to try these Traxxas. The problem I’ve found with this engine is that due to the anodising I can’t get a good connection so my ‘usual’ setup for twins, one remote plug connected to both glow plugs, just doesn’t provide enough current, hence why when I first ran the in-line it only fired up on one. So now I have 2 separate remote plugs, one for each.

 

Thats really helpful Ron, thanks.?

Edited by Low pass Pete
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