5 Cylinder Rotary Air Engine

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5 Cylinder Rotary Air Engine

This topic has 23 replies, 11 voices, and was last updated 23 May 2020 at 23:23 by duncan webster 1.

Viewing 24 posts - 1 through 24 (of 24 total)

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15 September 2018 at 21:14 #4285
Nigel (egi)
Participant
@nigelegi
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15 September 2018 at 21:14 #371906
Nigel (egi)
Participant
@nigelegi
Not sure where to post this as this is a rotary compressed air/steam engine designed to drive a propeller. 9mm bore and stroke and all designed by me, sadly I only have one rough sketch to go by. There are a few more details on my gallery pages and I do keep wondering if I should create some plans, just not sure how much interest there would be.
15 September 2018 at 21:16 #371908
Nigel (egi)
Participant
@nigelegi
The image doesn't give away the size of this engine and so thought this image might help.
15 September 2018 at 21:23 #371909
Wout Moerman
Participant
@woutmoerman25063
Very nice! I am very interested in compressed air engines and would love to see a plan or sketch. The porting is I n the rear of the crankcase? Can you explain the mechanism a bit more? Just 1 opening in the stationary part?
15 September 2018 at 21:24 #371911
Wout Moerman
Participant
@woutmoerman25063
And what kind of plane will it fly? Any idea for a airtank? Or am I getting carried away?

Edited By Wout Moerman on 15/09/2018 21:36:45
15 September 2018 at 21:26 #371912
Nigel (egi)
Participant
@nigelegi
Yes, the air goes in through the crank, which is stationary, this then comes out through the side of the crank and so is timed into each copper pipe that takes the air to the cylinder head. The piston is pushed down and at the bottom of the stroke there are holes in the side of the cylinder to let the air out.
15 September 2018 at 21:35 #371913
Nigel (egi)
Participant
@nigelegi
Posted by Wout Moerman on 15/09/2018 21:24:47:

And what kind of ane will it fly? Any idea for a airtank? Or am I getting carried away?

It took quite a long time to build and must admit that I probably won't build a compressed air tank or flash boiler.

Although it would look good in a Sopwith Camel or similar aeroplane.

Maybe some plans so that someone else can go the hole way with the build
15 September 2018 at 21:36 #371914
Nigel (egi)
Participant
@nigelegi
The piston and master corned with a 2mm drill acting as the gudgeon pin
2 October 2018 at 16:26 #374240
Steve Crow
Participant
@stevecrow46066
Hi Nigel, I'm very impressed with this build. I still can't get my head around the way the air intake works. Maybe you could post some more photos or a sketch to demonstrate.

I'm making a flat twin at the moment that uses a ball valve for the intake, similar to Gasparin Co2 engines.

Cheers

Steve
23 January 2019 at 08:47 #392489
Jordanbelfort
Participant
@jordanbelfort91109
Nice and very informative post…
23 January 2019 at 09:20 #392505
Howi
Participant
@howi
+1 for plans please
23 January 2019 at 12:27 #392547
Howard Lewis
Participant
@howardlewis46836
A compressed air version of the Gnome, Le Rhone,or Clerget. Excellent!

Howard
23 January 2019 at 15:08 #392571
J BENNETT 1
Participant
@jbennett1
Just curious, but why did you go for a rotary engine rather than a radial. Also, have you any idea of power output and air consumption?
23 January 2019 at 20:49 #392660
Nigel (egi)
Participant
@nigelegi
Not sure really why this configuration, but I sketched a rough idea and started by making the crankcase that is shown in the video **LINK**

The crankshaft is fixed and the air enters the end, comes out halfway down and enters one of the copper tubes – the tube will be the one connected to the piston that is at Tec
23 January 2019 at 20:52 #392661
Nigel (egi)
Participant
@nigelegi
I've not measured the power or air consumption and not pushed it too far – it runs and has become a showpiece sadly
23 January 2019 at 22:14 #392686
daveb
Participant
@daveb17630
I recall fizzy drinks bottles being used for on board CO2 tanks. Can't remember how much pressure they would take but it was a lot. Should be easy enough to pressure test a few bottles with a boiler test set.
23 January 2019 at 22:20 #392688
Nigel (egi)
Participant
@nigelegi
It would be nice to build a sopwith as an indoor free-flight model. The air tanks used for paintball might be a way forward
24 January 2019 at 09:52 #392729
Ian S C
Participant
@iansc
daveb, the ones with soft drink bottles used air pressure, the CO2 motors used the little CO2 gas cylinders.

Ian S C
24 January 2019 at 10:12 #392735
SillyOldDuffer
Moderator
@sillyoldduffer
Posted by daveb on 23/01/2019 22:14:16:

I recall fizzy drinks bottles being used for on board CO2 tanks. Can't remember how much pressure they would take but it was a lot. Should be easy enough to pressure test a few bottles with a boiler test set.

Quite a few people, many of them not very bright, have pressure tested plastic bottles. The most common reason is they want them to go bang! Mostly they report attempts to measure burst pressure, and their methods aren't likely to be accurate.

The highest burst figure I've seen was about 300psi, the lowest 80psi. Mythbusters reported bursting 2L bottles at about 150psi – they're more credible source than most,but don't get everything right!

Safe working pressure is another matter. One source claims the bottles are designed for 120psi and – in normal use – the internal pressure doesn't exceed 80psi. The other issue is the number of cycles the container can safely do before weakening. As plastic bottles are disposable it's unlikely the makers rated them generously. It's also unclear over what temperature range the bottles are safe. Cold would tend to make the plastic brittle and heat would tend to soften it.

If you know what you're doing, I don't think it unreasonable for a model maker to deliberately take the risk that his plastic bottles might explode. The amount of energy stored in the bottle is low. It's not in the same league as a boiler. Although the bang is loud enough to damage hearing and flying plastic might damage eyes, I think gloves, ear-defenders and protective glasses would be sufficient protection. Provided you're not actually holding the bottle when it goes off, that is!

Liquid carbon dioxide – as stored in a Sparklets bulb – is about 900psi.

Dave
26 January 2019 at 20:30 #393143
Nigel (egi)
Participant
@nigelegi
Posted by Howi on 23/01/2019 09:20:21:

+1 for plans please

I only have a rough sketch and no cae ability, sorry

Edited By Nigel (egi) on 26/01/2019 20:33:18
27 January 2019 at 11:07 #393200
Ian S C
Participant
@iansc
Only a rough sketch, that's often more than I have when I build on of my hot air motors.

Ian S C
27 January 2019 at 11:34 #393207
Nigel (egi)
Participant
@nigelegi
This was the limit of the plans that I constructed – really just to check the master and slave conrod clearances
23 May 2020 at 16:39 #474264
Nigel (egi)
Participant
@nigelegi
With lockdown I've been running more of my old engines and thought this was rather fun, the 5 cylinder rotary runs on what is effectively not much more than a fishtank pump, in this case it's the air pump for the lumbar support in a car seat.

I need to create some drawings as it runs so well.
23 May 2020 at 23:23 #474379
duncan webster 1
Participant
@duncanwebster1
Posted by Nigel (egi) on 23/05/2020 16:39:13:

……….

I need to create some drawings as it runs so well.

Very nice, an interesting project, get it written up for ME
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