ETW's Wyvern Gas Engine

[tangler]

Understood.

But one wouldn't like to let the side down.

After all the stripping down and re-fitting, I'm now going to see if she still goes......

Cheers,

Rod

[Roger B]

I missed the video of it running first time round. Really good    The paint job and finishing details are excellent    I hope you have no problems getting her running again.

[Ian S C]

Rod, I hadn't seen this part of this thread when I guessed (in the ME site) that your water tank was a bean tin!      Ian S C

[tangler]

Well, she does still go, but not with the ETW carb (see my warning about CO).  I'm going to make a simple air bleed carb based on the Matador design - that works fine.

I did wonder about disguising the bean tin but thought that corrugations might be reasonably authentic for the period 

Thanks for the kind comments.

Rod

[tangler]

Wyvern is now sporting a new carb, hacked out of 7/8" brass bar.  This is a simple spray bar, based on the dimensions of the Matador design.



She runs OK but is very sensitive to the mixture control, the needle just needs to be open about an 1/8 turn.  She would therefore seem to be over rich.  I haven't got an air bleed hole.  The feed and spray holes are both 1mm diameter.  Some R&D is required after the Guildford show.  Any advice would be most welcome.

I've made another video but she's jumping about a bit on the cheap Workmate clone.

[youtube1]https://www.youtube.com/watch?v=WS60rqETM5I[/youtube1]

[Jo]

I wish my R&B run like that 

A simple trick that I noticed on Eric's ignition box for running his engines on a workmate is his has a dowel the size of the holes in the top of the workmate in the bottom. Which is poked in one to the holes to hold the ignition firm on the top of the workmate   

Jo

[tangler]

I wish my R&B run like that 

She will.
 
Wyvern still needs a good whack from the electric drill to get her going - no flick of the wrist like some of the other Wyvern Youtubes 

See you Saturday 

Rod

[Jasonb]

A longer taper on the needle should give you finer adjustment. One up from that is to have the needle seat into a hole with a matching taper. A lot of the carbs on the hit and miss engines that I have done are very much on/off if built with the quite steep tapers shown.

J

[RayW]

Hi Rod,
I am new to the forum but have been following your progress closely as I have been building a Wyvern, but quite a few steps behind you. Thanks for all the helpful hints and ideas that I have picked up (stolen) along the way. Like you, I had one or two traumas but thrilled to say that the engine actually fired and ran briefly on the very first spin of the flywheel so looks like I did something right. There a still a few details that I want to sort out before getting to the painting stage, but well pleased with progress to date. Have posted a short video of the second run on YouTube.
<a href="https://www.youtube.com/watch?v=-3yJFchXy_Y" target="_blank">http://www.youtube.com/watch?v=-3yJFchXy_Y</a>


Ray Wilkinson

[tangler]

 

[Themule]

Rod - did you come to a conclusion on the carb design in the end? I have come to a point in the build where I am about to start on the carb - not sure whether to follow the original design or not.

Andy

[RayW]

Hi Andy. As you will see from my video, my Wyvern runs well on the carb as per the plans. I made it exactly as shown, with gas and petrol jets, but have only tried it on propane so far with excellent results. If you have any questions about the build please free to ask.

[tangler]

Very pleased to see Ray's engine running so well with the original carb design, albeit on propane.  I really don't know what's wrong with mine (bad workmanship?) but I really must have another go at it.

Ray, are you using a demand valve on your propane feed?

Cheers,

Rod

[RayW]

Hi Rod. No demand valve, just the carb and an adjustable regulator on the gas bottle. Pressure is extremely critical. You only need a whisper of gas and the least bit too high or low and it won't run.

[Themule]

Thanks Ray - Thats good to know. I will crack on with it and see how I get on. Every other part is now made, apart from finding some tungsten disks for the contact breaker and soldering them on and of course timing and fitting. Its the first IC engine I have tried so lets see. Thanks again. Andy