Author Topic: Retlas  (Read 67668 times)

Offline Chipmaster

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Re: Retlas
« Reply #330 on: September 09, 2018, 09:15:25 AM »
Yes Jo youíre right, a stud and nut will be in keeping with the engine, I wasnít thinking  :Doh:
The covering and route for the wires is still being considered.
Andy

Online Jasonb

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Re: Retlas
« Reply #331 on: September 09, 2018, 01:39:34 PM »
Nice slotted screw with a slightly domed top would also look the part and be easy to access should you want to make adjustments.

You could also run the wires inside a bit of brass tube with just the end exposed to allow for adjustments

Offline Chipmaster

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Re: Retlas
« Reply #332 on: October 23, 2018, 08:48:46 PM »
I made a wooden box to support the cooling tank and contain the Minimag ignition system. The brass cooling tank was painted to avoid having to keep it polished. No firm plans for the exhaust system yet, whether to have a simple pepper pot style silencer on the end of a short stubby pipe or route a longer pipe down beneath the engine.  :thinking:

Andy

 
P1080484 - Copy by Andy, on Flickr

P1080488 - Copy by Andy, on Flickr

P1080498 - Copy by Andy, on Flickr


Offline Roger B

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Re: Retlas
« Reply #333 on: November 03, 2018, 07:21:34 AM »
Looking good  :praise2:  :praise2: My only thought on the exhaust would be to keep it away from the wood work and paint to avoid oil and soot.
Best regards

Roger

Online Alyn Foundry

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Re: Retlas
« Reply #334 on: November 03, 2018, 11:29:58 AM »
Good morning Andy.

Yet another missed thread, the engine and ancillaries are looking beautiful, well done!

The Retlas was loosely based upon the Size 1 vertical gas engine. They would have used the same exhaust bottle as was fitted to our size " 0 "  because the " 0 " appeared much later after the " 1 " did. I know Geoff had some cast recently but he's still reeling from the bill they hit him with!! They had so much trouble in getting sound castings they charged him £90.00 each!! :o

You might like to think about the air filter/muffler ? This part was unique, in style to the Gardner range. It would have to be made a little bigger for the Retlas however. Oh, and I cheated a little with the " 0 " by just using some Steel tube, the original outer case was actually made from sheet, rolled into a tube and riveted together.

The whole is a real credit to you Andy!

Cheers Graham.

Offline Chipmaster

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Re: Retlas
« Reply #335 on: November 03, 2018, 08:54:29 PM »
Hi Graham - thanks, almost there.

Strewth, £90.00 for a small exhaust bottle makes the Robinson HA platform castings sound cheap as chips. Mike C and I borrowed your patterns and had a small batch cast by the AJD Foundry and they cost about £20 each. I only wanted one but it's size isn't in proportion with the Retlas. I have used it with the engine and it is very effective.
Here are a few pictures of it.
Silencer (1) by Andy, on Flickr
Silencer (2) by Andy, on Flickr
Exhaust bottle 8 by Andy, on Flickr
Exhaust bottle 7 by Andy, on Flickr
Exhaust bottle 1 by Andy, on Flickr

I think I'll fabricate an exhaust bottle as I did for my Gardner O Type years ago.

My Gardner O Type [6] by Andy, on Flickr

I agree with you about the air filter / muffler, I'll make one following the style in your plans for the O type.
My Gardner O Type [1] by Andy, on Flickr

Andy


Offline Chipmaster

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Re: Retlas
« Reply #336 on: November 03, 2018, 09:06:06 PM »
Hi Roger, I agree, the exhaust should be aimed away from the wood. I'll try a vertical outlet first and if it's a messy exhaust turn it to horizontal, pointing away from me - poor spectators  :mischief:

Andy

Offline Chipmaster

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Re: Retlas
« Reply #337 on: November 13, 2018, 08:20:44 PM »
i made an air filter / muffler in the Gardner 0 type style this afternoon by boring out a piece of stainless steel and pressing in stepped brass ends.

 Andy

Offline Ye-Ole Steam Dude

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Re: Retlas
« Reply #338 on: November 13, 2018, 09:12:54 PM »
Hello Andy,

That is beautiful and just adds a touch more to an already beautiful engine.

Have a great day,
Thomas

Offline Chipmaster

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Re: Retlas
« Reply #339 on: November 14, 2018, 10:29:19 AM »
Hello Thomas,
that was another finishing touch, thanks for the compliment, I hope to have the engine running again very soon.
Now Iím looking for clips to fasten the tubes to and from the water tank.
The tube is 5/8Ē ~ 16mm od. The commercial worm drive or Jubilee hose clips available look wrong because the bands are too wide.
Thinking of my BSA and Triumph motor bikes about 50 years ago, I think  the clips used on the oil tank hoses were slender and might look right but theyí donít  appear to be made today...perhaps because they allowed oil leaks.
Andy

Offline michaelr

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Re: Retlas
« Reply #340 on: November 14, 2018, 11:08:42 AM »
What about O clips they start about 6mm band width, but I would think the band width could be reduced to suit your requirement's.
https://docs-emea.rs-online.com/webdocs/151b/0900766b8151b32d.pdf


Michaelr

Offline Chipmaster

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Re: Retlas
« Reply #341 on: November 14, 2018, 11:46:53 AM »
Thanks Mike, those O clips look far better so Iíll try them.

Andy

Online Jasonb

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Re: Retlas
« Reply #342 on: November 14, 2018, 03:51:50 PM »

Offline Chipmaster

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Re: Retlas
« Reply #343 on: November 26, 2018, 12:28:39 PM »
The Retlas has needed quite a lot of adjustments to the governor, valves, gas system and ignition to get it to slow   down and run without bouncing around. I have got it running reasonably slowly as can be seen in this video that I made yesterday afternoon. By the end of this video the engine was no longer clamped to the workbench and it sat still but there's still a way to go to get it 'right'.

t=1s

The Retlas can be violent, after all at about 120 cc it's a large model and in its present state it is best attached to something immovable like my workbench for these trials otherwise the governor arm swings about wildly, so much so that the counterweight becomes superfluous. I have considered whether it would be possible to dampen its movement.

I have thought about whether the engine could be pacified by reducing the air intake diameter. Does anyone have  any experience of the effect of altering the air intake on a hit and miss engine?

The whining of the timing gear is a bit too loud. When I built the engine I made an eccentric shaft for the half time gear copying the Gardner 0 type method for adjusting backlash. I find the whine stays the same no matter what adjustment I make - tight or loose. The shafts are also spot on parallel. I know straight cut gears are usually noisy but.....perhaps these gears from HPC just arenít a Ďgoodí meshing pair. Once Iíve got the engine running nicely I might look into getting a pair of helical gears that might solve the problem. I have also tried reversing the pinion on the crankshaft and reducing the engagement by moving the pinion outwards along the crankshaft but the whine stays put. I attach a picture of the gears, there is a lot of backlash with this setting.

To be continued....
Andy

« Last Edit: November 26, 2018, 12:52:29 PM by Chipmaster »

Online Jo

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Re: Retlas
« Reply #344 on: November 26, 2018, 12:44:27 PM »
 :thinking: The mesh on those gears seem a bit wide Andy. Is the adjuster eccentric bushes that would allow the two shafts to be closer together.

Jo
Enjoyment is more important than achievement.