Raleighcopter

Two thermistors are working. Had to fix the thermistor library I'm using. No thermistors plugged in so no real data but they're 5904 and 5905. Rpm will be 5906 and the air pump command will be 5907

Glowgeek

Great work, Dave. You're making some headway now.

Rcplanedan

would it be a bad idea to recirculate the breather back to the intake , most asp 4 strokes are setup like this..i ran a couple of flights like this today .near on zero mess on the plane, the orings on the push rod tubes to the heads had gone hard ..since shops were closed i just cut some glow fuel hose and made some temporary seals, worked very well for time being..

1967brutus

I can't say WHY experiences differ, but some people report that recirculating crankcase effluent back to the intake works without problems, however I have poor experiences with it.
My FS91 had that from factory but it resulted in very irregular running.
I used transparent tubing, I couldsee the oil blobs moving through the tube and every little blob entering the intake, seemed to disturb the engine a bit.
I did not like it, I plugged it off. Others seem not to notice any irregular running.

I can only conclude that the engines all run the same, and that some people are more bothered by smaller irregularities...

Rcplanedan

every little blob entering the intake, seemed to disturb the engine a bit.
I did not like it, I plugged it off. Others seem not to notice any irregular running.

I can only conclude that the engines all run the same, and that some people are more bothered by smaller irregularities... [/QUOTE]
I definitely noticed it made a slight difference to running of the engine, well it does seem a tad rough from idle to to part throttle..but its definitely not a real problem ,well for me anyway 😉,

Raleighcopter

the same applies to various gas conversion methods. they accept a crappy running engine and then use that to say a solution like ours isn't needed because their engine runs fine. it's a bit like stepping over a pile of dog**** in the middle of your livingroom and acting like it's not there because you can still use your sofa.

Raleighcopter

i had no idea pc boards were so cheap. i can get 50 2 layer,1.5x2" boards for $10 shipped. i guess i need to learn eagle or one of the pcb design tools and generate some design files next.

stay tuned.

Glowgeek

RE recirculation crankcase venting:
The best I've seen this work, the least amount of negative effect on engine running, is to port it into a velocity stack.

Raleighcopter

re: recirculating crankcase venting, don't do this with a new engine as you'll be recirculating the bits that need to wear off during the break-in process back through your engine.

John_M_

That os GF40 I ran in the super cub had a internally plumbed recirculating crankcase breather ( piston driven pcv system )... recirclated through a passage in the cam follower bushings up the pushrod tubes into the rocker box, and then down through a small orfice into the intake port... that engine always had a mid throttle burbel that couldn't be tuned out 100%... I ended up plugging that orfice in the intake port, and then venting the rocker cover with a small threaded barbed nipple ( similar to what Bert has done )... I left the pcv check valve in the crankcase backplate, and just vented the crankcase out the rocker cover... big improvement in throttle response and got rid of that mid throttle burbel... mind you this is with a walbro gas carb, so the oil content in the fuel mix is only 5%... and there was other crankcase volume displacement issues occurring as well.

I think venting out through the rocker boxes and then out through a piece of tubing in a position to limit the oil residue from getting on the airframe is the better way to go.

John_M_

You must be a dog owner

Raleighcopter

I am a dog owner without a pile of crap in my living room.

Glowgeek

I have never tried to recirculate crankcase oil through the intake tract with a gas engine. Even though a gas premix uses 3x-4x less oil than a methanol premix, gas has a much narrower stoichiometric range. Maybe it would work well with gas if recirculated through a velocity stack. Something to try, perhaps. Makes some sense to me that the oil droplets would have a chance to re-atomize as they pass through the venturi. Not sure about the evaporative side of it but still, worth a try.

I agree, Dave. I don't recirc crankcase oil until the engine is well run in.

Raleighcopter

i spent a few more minutes writing code. Still untested but now it should measure RPM. just need to program the air pump control now. maybe tonight but certainly before the week is up as i'm traveling for work on wednesday and will have some hotel time to work on it. although incomplete, it's posted on github as experimental software at this point is anyone is interested.

Glowgeek

Dave, is the new controller Xiao? Will I be able to mod my controllers with the new PCB and components and flash them with the new firmware?

Raleighcopter

If you can unsolder the leads from the Xiao and clear the pin holes you should be able to flash it and attach it to the new populated circuit board. I may make it use the castellated connections so it's smaller and you don't need to clear the pin holes of solder. I haven't gotten that far yet. I've got one prototype built so far and I need to finish the software and test it before (learning kiCAD and) moving to the circuit board. I do plan to deal with the part of the code related to the display after the board is designed and ordered. After that, I'll design a case and bezel/case for the remote display. I imagine the controller will look about like an 8 channel receiver without antennae.

Glowgeek

Awesome. Clearing the solder won't be an issue. I have to say, being so long since I've flashed my Xiao boards the hardest part will be downloading and uploading the new firmware. I'm pretty sure I've forgotten everything I learned.

Glowgeek

Dave, one last request. Would like to be able to simply plug in the CDI rpm output into the controller. Possible?

Raleighcopter

I'm using one of the uln2003 channels to buffer rpm from the cdi. You should be able to plug the cdi directly in to the controller.

Raleighcopter

making progress....

Glowgeek

Hee, hee.......haw. Good one, Dave.

Well, what do you know, the cartoon programmer is left handed too!

Cat 1

My Feedback: (1)

SOOOOO.... For some reason I stopped getting updates on posting from RCU and I thought the thread had gone Dead. Was pleasantly surprised that I have much catching up to do.

In June I got the bump to the "Big Chair" at work. My former boss and the company parted ways and I got the Nod. In charge of the whole maintenance department effort now as the "Director". Keeps me busy and has really cut into my "free time", but its a good challenge and a good way to cap off my Aircraft Maintenance career. Will add a few more pennies to the retirement savings too...

Will take a bit to catch up with "the effort" but some of it looks very exciting.

Chris

Glowgeek

Congrats, Chris. A great career accomplishment. Are you sure you're still allowed to talk to us meager engineers?.........What, with you being a fancy shmancy exec and all.

Rcplanedan

it was a thought of course,seeing that as from the box asp fs91 and asp fs120 i have both run crank case breather back to intake, well i had never run one in this configuration, so after a dew flights with the boxer, sure i discovered that yes it surely doesn't run quite as smoothly, so back to atmosphere it goes now..
Haha sure i let the dog crap on my living room floor,but no more of that,its just terrible i know😳

Rcplanedan

probably better to just keep the waste discarded to atmosphere,,its definitely waste after all..