John_M_

Looks like Mike's got some parts still available for the ASP / Magnum FT160's.

https://www.mikegoesflying.com/produ...-engine-parts/

John_M_

Ahh, so now I see where the leak is on Cat's cylinder head... the bronze seats & guides are cast in as one piece... but when they bore through the bronze cup to open up the ports, there is an area around the valve seat over the ports that could leak if there are casting porosities / imperfections between the bronze and aluminum head castings,

Cat 1

My Feedback: (1)

Yes John... the leakage is more apparent around the port clearance.. Im assuming its also harder to get a long lasting gas tight fit around a large cast in part than it would be to do the same with a pressed in style seat,

John_M_

Yes, when you cast around a slug of metal with a hot molten alloy, you can get super heated gasses form at the boundary layer of the different metals that can get trapped, causing the porosity... as well as the expansion and shrinkage as the part is initially cast, then cooled... preheating the mold slugs before the pour, would prevent most of the dissimilar shrinkage and off gassing... It wouldn't be an issue until you remove some of the metal around the port... now you exposed the boundary layer of the two metals across the machined port, reducing the seal area around the seat over the port... When you machine the two parts separately with an interference fit, and then pressed together, you have a tight seal at the boundary layer.

Raleighcopter

The air pumps I ordered should be here this week. I'll be able to see how they operate soon. I've been looking into integrating it into the xiao controller. If 256 steps is sufficient like Chris tells me, I'll just need to pick a digital pin, add a MOSFET, and use analogwrite to control it. Reading rpm will be fairly easy too.

This is important. I don't want to write software that you cannot use, Chris. Do your graupner receivers have s.bus ports or do I need to pick up a couple more actual channel pins?

Cat 1

My Feedback: (1)

Sorry I missed you query Dave.. The graupners can output s.bus (and many other protocols) but I'm not sure if the port (one of the channel pin sets) can be used concurrently with the other channel output for providing the other channels. I will check that today. I have used it as "single line" to a controller but I think in this case we need the other channels to be active for the rest of the plane.

Raleighcopter

How about a mixture channel input and a separate control channel input rather than sbus then. Sbus will require an additional transistor and resistor. I could program it so a signal less than 1500uS sets the air pump multiplier from your program and if it's over 1500uS it could do things like choke, tune acceleration, etc.

John_M_

All the sbus channels are available off the sbus port... use a hub so you can provide an sbus input to your MCU... the hub will allow you to use the sbus channel outputs if you plan to use them... the hub is no more than a common pin buss, in the case of futaba, their hub is just a 3 port buss... you can make your own, if need be.

For my CDi, I ended up cascading two MCU (Arduino's or XIAO)so I could use both interrupts and micros together without causing the timer latency associated with interrupts... I don't think you'll run into that issue with what you're doing, but its some info that I got from one of our members that sets up the MSD digital mags.

Cat 1

My Feedback: (1)

Dave - I think regular inputs would work well enough and do away with the S-bus programming and setup - I did have a "Primer" setup with a single input as you can use the "not running" trigger (in my original code) and look for a high or low signal from the channel input - I used this successfully

Raleighcopter

the xiao should be able to use interrupts on all pins except it cannot have an interrupt on pins 5 and 7 at the same time. there's plenty of pins available such as pins 1, 6, 7, 8, 9, and 10 so we should be good. i think i'll use interrupts for the additional channel and for reading RPM.

ultimately, i need to know how we woud like to use the air pump and how to do that in conjunction with the solenoid valve or possibly a configuration that doesn't use a solenoid.

i could see starting the pump manually for a short time period to prime the engine.
i could see adding a multiplier to the air pump function to tune the tank pressure and to tune the increased need for fuel when the engine accelerates.
i can see using the pump to pump fuel back out of our tanks at the end of the day by pressurizing the tank.

did i miss anything? anybody else have any ideas they want to throw out there?

John_M_

Interrupts will work well in your situation, but doesn't pair well with micros / timers where you need fast response...

Don't do away with the STHIL solenoid valve, thats your remote "digital needles" for tuning... use the air pump to mimic exhaust tank pressure... otherwise, if you get rid of the solenoid valve, you're back to a traditional carb setup, tuning the hi/lo needles, but with remote adjustable tank pressure... use the 2 together with their own channel mixes, one for the fuel mixture, and the other to adjust tank pressure in response to RPM... two adjustable mix curves that an be fine tuned... then you can save each profile under each model memory... you'll probably find that tank pressure will be more common to each engine ( with small variations ), than the fuel mixture.

Raleighcopter

I think Chris was interested in using just a pump on some engines, or at least seeing if it will work. I like the idea of a solenoid and a pump too but if Chris can make it work with just a pump, the controller should support that setup.

John_M_

Oh, I'm sure it will work with just the air pump for tank pressure... Chris has proven that it can mimic exhaust tank pressure... it would be similar in the way you tune a std carb setup with exhaust pressure, but you can now manipulate the tank pressure... It could also be adapted to glow fueled engines as well... My interests lies solely in adapting the walbro pumper carbs, although I have a remote servo operated choke, a remote primer using the air pump possibly, would be interesting.

Raleighcopter

It would be posh, you see. Just like that big cub of yours with an onboard starter.

Glowgeek

No need for an air pump, or any type of primer, if you leave fuel in the tank between flying sessions. Longcterm storage is a different story, If you let the carb dry out a large syringe, like those found in farm stores, work quite well to temporarily pressurize the tank through the vent tube. I have used that technique for years on 2 stroke cube carbs and Saito gassers.

From my limited experience, so far, I'd rather install a crap trap than an air pump.

Raleighcopter

But you see, a syringe isn't posh, and we're trying to be posh too.

Glowgeek

I'm still waiting for someone to try the air pump alone, with no solenoid, using a 2N glow carb and gas. That will be an eye opener, perhaps.

Raleighcopter

Chris!

Cat 1

My Feedback: (1)

Dave and all,

Sorry for the slow replies - We are fighting cold here - real cold!!!! -30C today all day and approaching -50C tonite with wind chills - What a start to winter - El Nina is going to beat us up this year.

I plan to use both the systems (pump and solenoid) on the boxer and I think it will be the standard for most systems - I am going to try just the pump on the OS .37 because being a heli engine and the carb is already close to a reasonable tune when converted. The pump will just fine tune the mid range. I think the code could be written in such a way that you could select option (in setup) to enable and disable both parts ?

Chris

Raleighcopter

It's been a 50f here and I'm miserable. I can't imagine -50c.

Raleighcopter

fresh from China. They're cute too.

John_M_

50f... its gets down in the 30''s here in California this time of year in the early hours of the morning... Cat's water bowl has a 1/4" ice puck floating... cat looks at me, like do something about it already... I know the weather Cat has to deal with... I've been to Chicago in December, -15 and the humidity is zero, all frozen on the ground... you step off the plane and your lips shrivel up and bleed.

Cat 1

My Feedback: (1)

John.. The cat needs one of these - Keeps my puppy watered and happy




Looks like we will be spared from -50 tonite - only -48 with the wind



The humidity does funny things when it gets so cold - it crosses a line at around -40 where it can be 100% humidity and ice fog forms but the moisture content is so low it hurts as you describe - keeping the house humidity up is a real chore in the winter as you have to balance super dry with frost on the interior windows. Does make for a awesome science trick though - this is from Christmas a few years back - The high point of my acting career !!!

John_M_

Well I could do the bowl warmer, but it only occurs for just a few days in the cold months... he has a bowl inside were he resides most of the time ... I saw a placard on Amazon that said, "Its The Cat's House, We Just Pay The Mortgage" .



That kind of humidity can't moisturize ... I've seen the lake effects form over rivers in those minus cold temperatures, odd to see fog meandering through the country side.

Glowgeek

I know what cold is, part of why I live where I do.

When I stepped off that Twotter 630 miles north of the AC it was -68°f with 45 knot winds. That's about 128°f with wind chill. That feak'n hurt! Hint, hint......standard issue military extreme cold weather gear is not that great. I scoff at -40C.