So I've been building an ultralight

[Zebidee]

I also need to finish off the electrical, which is quite funny I dragged my feet on that seeing as how I used to be an auto electrician 😂

I think I understand this reluctance.

It is a funny thing, but if I've ever done something professionally I hate doing it on my own time. Feels too much like work. Like, I spent many years until my mid-30's in all kinds of accounting roles, I'm good at it, but hate tasks like tracking costing for my own projects. I won't even do my own tax returns though they are simple enough.

[danny_galaga]

I also need to finish off the electrical, which is quite funny I dragged my feet on that seeing as how I used to be an auto electrician 😂

I think I understand this reluctance.

It is a funny thing, but if I've ever done something professionally I hate doing it on my own time. Feels too much like work. Like, I spent many years until my mid-30's in all kinds of accounting roles, I'm good at it, but hate tasks like tracking costing for my own projects. I won't even do my own tax returns though they are simple enough.

We call it 'plumbers tap' 😄

[bobbyb13]

"The cobblers children have no shoes..."
 

[danny_galaga]

So there's been a difference of opinion on what comes with the second hand engine I bought. There are some parts s missing off the carbies. Would cost over $300 landed for a few bits of metal that aren't even made for aircraft. Well one piece is but it's just a flat bit of steel. So I got some scrap metal for that piece, and AliExpress and a Go kart spare parts shop for the other bits. More like $50 and the satisfaction of not paying the Ro-tax 😄

[Zebidee]

Love how dodgy it seems at first glance: used motors with missing parts, bit n pieces from Aliexpress and go-karts. Yet I am optimistically confident you are doing it right (interpret as: I have no idea  ).

Work a little WD40 or similar into that throttle cable sheath and check it occasionally for corrosion - I got my 1975 Holden HZ ute airborne thanks to a stuck throttle, somehow survived, hate to think what it'd be like for someone airborne already.

[danny_galaga]

Love how dodgy it seems at first glance: used motors with missing parts, bit n pieces from Aliexpress and go-karts. Yet I am optimistically confident you are doing it right (interpret as: I have no idea  ).

Work a little WD40 or similar into that throttle cable sheath and check it occasionally for corrosion - I got my 1975 Holden HZ ute airborne thanks to a stuck throttle, somehow survived, hate to think what it'd be like for someone airborne already.

😄

First car I ever drove was a HQ. Tanks 😊

Interestingly, the Rotax carbies are full throttle as a default.springs hold them wide open. The idea being if a cable breaks you can still where you are going. If it broke and went to idle, you're gonna have to land. Only thing is that the engine is only rated to full power for a number of minutes. I think if it happened to me, I would switch off one of the ignition switches. You lose maybe 150 rpm. Would still be NEARLY full power but not totally wringing it's neck. Then alternate the switches every 5 minutes or so the plugs don't foul.

This weekend, I think I have everything I need to put in some oil and coolant and start him up. Of course nothing is ever easy. Imma guess you know how to change the oil on a car. Well forget all that on the Rotax! It's a dry sump engine. Basically to fill it up, you take off the return line on the oil tank. Point that into a container. Plug up the hole in the tank. Pressurise the tank to 10psi via the vent line. Take out the top spark plugs. Now spin the propeller around by hand maybe 100 turns 😜

Even most other aircraft enginesis roughly the same procedure as a car. Grrrr. Lucky there's a compressor in the hangar...

[nitrogen_widget]

so what is the difference between a rotax and a rotary engine or are they basically the same thing?

[danny_galaga]

Rotax is a brand, not a type. They make engines for motorcycles, jet skis, go karts aircraft.

A rotary engine is similar to a radial. So the cylinders are in a star formation. But CRANKSHAFT is bolted to the firewall and the propeller is bolted to the crankcase. The whole engine spins. Good cooling, HUGE torque (a 110hp rotary had more torque than a GT40!). but you can imagine a large unwanted gyroscopic effect. They were pretty much history after WWI.

The Rotax engine I'm running is a 4 cylinder 'boxer', like Subaru or Porsche etc.

[danny_galaga]

Milestone for the millstone


https://youtu.be/cPObCLKcieQ?si=Wp_gPVCQ2n4YtV4l

[nitrogen_widget]

is that how it's supposed to sound?
or does it need tuning?

[pbj]

I’ve told this story here before but it bears repeating.

So, I drove a home built car once.  It weighed 1400lbs and had 168 horse power.  It was the fastest vehicle I have ever driven.  But the guy that originally built it never drove it more than around the block. He was some kind of engineer that worked on satellites and had the guys in the shop assemble it after hours.  It was modeled after a BMW concept roadster that never went into production.

My dad bought it and let my wife and I take it down the highway.  And I’m not joking, you farted on the gas pedal and you were over 100mph.

Everything was great until it was time to go back home and we had to sit while a gate opened.

The genius had used an oil temperature gauge with rubber hosing.  While you were moving; there was enough air flow to keep things cool.  Have I mentioned the engine was open air and mounted directly behind the driver and passenger?  Gas tank was right beside it.

Anyway, long story short, the hose melted and sprayed oil all over the engine block.  I used to have hair halfway my back.  It caught fire.  I am thankful every day that a young girl came running out from the neighborhood pool with a fire extinguisher and saved me and kept the car from exploding.  I had second degree burns on my neck and back and got a clipper cut.  The haircut lady  was apologizing the entire time.

Quadruple check everything, Danny.  No weird ---That which is odiferous and causeth plants to grow--- shortcuts. 

[danny_galaga]

Nitrogen widget, yeah notice it was fine to start and then went really rough? First I thought the carbs might simply be unbalanced, but I'm pretty sure now there's a blocked jet or cracked O ring etc in one or both carbies. I was able to easily get the bowls off to have a look. First glance looked good but then noticed the petrol 'varnish' that can build up. Cleaned all that out and checked the pilot jets but nothing out of the ordinary . So this weekend I'm taking them off completely and giving them a more thorough inspection at home. Mat need overhaul kits, which are over 200 USD each carbie. Ouch!

PBL, oil and fuel pressure lines in the cab give me the Willie's, for exactly your unfortunate experience. Electrical for me.
And yes, I'll be double quadruple checking everything. The aircraft mechanic at the field will also get his boys to go over it too. He will do the first hour flying. I'd love to be the first but it's not recommended. This guy has tested probably hundreds of aircraft in his time.

[danny_galaga]

Carbie. Notice the choke is quite a complicated beastie. Carbie also compensates for altitude so that it leans out the higher it goes. Not perfect, but acceptable

Edit: LEANS, not MEANS. stupid auto correct

[Zebidee]

Yikes, that does not look like fun.

I think I've already related how I once pulled apart the carbie from my Datsun 120Y, cleaned it, reassembled it, and everything worked 100%... but there were 4 parts left over!

Something like that clock we've probably all pulled apart as a kid.

Then there is the challenge of balancing twin carbs

Good luck! Give yourself a good clean space to work in. Take lots of photos (so you know how everything goes back together).

[danny_galaga]

Also, I'll completely do one carbie at a time, so I can also reference the other one

[nitrogen_widget]

is throttle body out of the question?
for an old car those things are great.
so easy to tune.

not sure if planes can even use them since more stuff can go wrong with them.
what about fuel injection?
or same reliability issues?

my dad has an old triumph that needs a full restore.
it was a straight 4 with dual carbs and if one had an issue he wasn't going anywhere enjoyably because two cylinders were getting more gas than the other 2.
Imagine it's like that?

yes i have not much of an idea so curious.

[danny_galaga]

There is a fuel injected version of this engine. Fuel injection is fairly popular in aircraft now, but not ubiquitous like in the auto world. Too expensive and too much mucking around for me to convert.

[danny_galaga]

Apparently the weight of the carby floats can increase over time. Something to do with it retaining too much fuel or summink. It's a big enough deal that I was going to just replace them regardless. But surprise, surprise- they ain't cheap! Luckily I found my little set of weights I made over 30 years ago when I had access to a really accurate set of digital scales. Smallest weight is 0.05 grams (50 milligrams ). So I knocked up a simple beam balance scale ⚖️ and weighed the floats. They come in pairs and can't weigh over 7 grams. Both sets came out at 3.2 and 3.15 😎

Yes, I could buy a set of accurate digital scales quite cheaply, but where's the fun in that? Building the scales was probably the most fun I've had with this airplane for months 😄

[nitrogen_widget]

sounds like the floats are not water or fuel tight right?
what about new floats?
IDK my small engine experience is my old log splitter with a pull start you have to wind manually and a magneto stopped providing spark and after futzing with magneto and about an hr of yanking on it with no luck total, my solution was to go look for a newer engine. which i found. it was so old it has a belt drive electric start, but it does have a coil. so newer!

i just have to wire it up properly now because it was on an old dead mower someone apparently stole the wiring from?.

[danny_galaga]

sounds like the floats are not water or fuel tight right?
what about new floats?

You need two pairs of these.

https://www.aircraftspruce.com/catalog/eppages/tempest_ms80-430.php?clickkey=409219

[Zebidee]

Wow, you could probably buy a new log splitter for the cost of those floats!

I'm somewhat fascinated with why the floats get heavier over time, and if so, why the heck Rotax (or Marvel/Schebler) make them out of whatever material allows this to happen.

[danny_galaga]

Wow, you could probably buy a new log splitter for the cost of those floats!

I'm somewhat fascinated with why the floats get heavier over time, and if so, why the heck Rotax (or Marvel/Schebler) make them out of whatever material allows this to happen.

So they can sell you new ones 😁

The link I pointed to is an aftermarket one. They guarantee they won't soak up fuel.

[Zebidee]

Perhaps the aftermarket are worth it, but still seems like they are gouging.

I'm wondering, can you dry the old ones out? Like, wash them then leave then in the sun for an afternoon?

[danny_galaga]

Perhaps the aftermarket are worth it, but still seems like they are gouging.

I'm wondering, can you dry the old ones out? Like, wash them then leave then in the sun for an afternoon?

It's all academic. You might have missed the bit where I weighed them and they were well within spec.

I don't think 'drying' them out will achieve anything. In normal operation, the floats are in the fuel 24/7

[Zebidee]

Didn't miss anything, and agree. Just curious about the processes involved (chemical I assume) to make them heavier.

[danny_galaga]

Yeah, I'd never heard of such a problem before. Any other fuel float I'd seen was either stamped soldered brass or plastic. Apparently the older type of floats can spring a leak though so it's not simply a matter of 'they made 'em better in the old days'

[danny_galaga]

Well, it turned out I had the fuel IN line mixed up with the fuel RETURN line. It meant the carbies were only getting a small flow of fuel 😄

Well at least I know more about Bing carbies now I guess...

https://youtube.com/shorts/TQjM3ppLkf4?si=uFY5rDSDK6ggkx_7

[danny_galaga]

Progress. Brakes still suck though.

https://youtube.com/shorts/HykMX5Zuwoc?si=oqlwhcOXLNMEqSZ

[pbj]

Is 19-2010 when you started building this?

[Zebidee]

He's doing well, considering this was his first prototype

Power is 100% renewable, no carbies, no lithium battery to burn down your house, and you can recharge in seconds.

https://youtube.com/shorts/SyB1-iq5EBE?si=Xf8NBXdRZTjCmGel

[danny_galaga]

Is 19-2010 when you started building this?

😎

http://forum.arcadecontrols.com/index.php/topic,159241.msg1674921.html#msg1674921

[danny_galaga]

Well, I finally fixed the brakes. I can now turn left AND right when taxiing now 😀

[Zebidee]

  Whenever anybody talks about brakes on an aeroplane, I *always* think about Bugs Bunny saving the day with "air brakes" in the classic HB cartoon "Hare Lift".

Here's a link for your benefit - it is a shortened version of the cartoon, only 3 minutes with beginning and end, the air brakes bit is right near then end. Love it, classic nonsense!

[RandyT]

Well, I finally fixed the brakes. I can now turn left AND right when taxiing now 😀

Meh, waste of time.  You could have just made a circular runway and traveled it counter-clockwise

[danny_galaga]

Zebidee- love it!

RandyT. Even with a circular runway, a tail dragger is hard to keep under control on the ground with just one brake working 😄

[CheffoJeffo]

Posting here so that I receive notifications. All I ever see on FB are postings about food. 

[danny_galaga]

Posting here so that I receive notifications. All I ever see on FB are postings about food. 

That was just a phase...

[danny_galaga]

Decided I should put a battery isolator in.

[Zebidee]

You should also add some switches/buttons for the stinger missiles, bunker-bombs, self-guiding torpedoes and .50 cal machine guns.

It's the only way to be sure.

[danny_galaga]

You should also add some switches/buttons for the stinger missiles, bunker-bombs, self-guiding torpedoes and .50 cal machine guns.

It's the only way to be sure.

Have I mentioned the right hand toggle switch?