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  1. n3puppy

    POLINI THOR 250

    Arctic Blast ZR - $8255 plus freight and set-up https://arcticcat.txtsv.com/snowmobile/mid-sized/blast-zr Yamaha version is the Venom - $8199 plus freight etc. https://www.yamahamotorsports.com/trail/models/sxvenom
  2. n3puppy

    premix oil

    Rotella has many uses ;) Back in the day - Late 1970's - had a good friend who was a supervisor at an OMC Evinrude Plant. Told our snowmobile club that OMC 50:1 oil was nothing more than Rotella. They bought it in 55 gallon drums, added blue dye coloring and repackaged into OMC...
  3. n3puppy

    Vibration free powerplant.

    The OPOC engine has been around for 139 years and keeps reappearing. Why? Because it offers a number of potential advantages if some of the mechanical limitations are solved. As technology improves it may make a Spark ignition, petrol fueled OPOC economically feasible. Way back in the 70's...
  4. n3puppy

    Vibration free powerplant.

    While the title doesn't say opposed - In Posts #11, #12 and #16 Niels explained the type of engine he was discussing and asking input on - OPOC. Not opposed engines as used in Snowmobiles, VW.s, Corvairs, BMWs OPOC engines have been around since 1882...
  5. n3puppy

    Vibration free powerplant.

    There was never an OPOC (opposed piston opposed cylinder) snowmobile engine of the type being discussed here. Neither were VW's, Corvairs, or BMWs.
  6. n3puppy

    Vibration free powerplant.

    That is what I was thinking - Propellor loads - but a little different view. What happens in a climbing turn? Load is different on inside and outside props due to arc of the turn. Granted not as bad as widely spaced twin engines mounted on different wings. But still there.
  7. n3puppy

    Vibration free powerplant.

    Ok my question. The Junkers 3 post talks about not needing gears to keep pistons in sync. Use permanent magnet generators to do that. I can see how at cranking speeds to start, it could work. But at full power - If the magnets are strong enough overcome combustion forces and keep pistons in...
  8. n3puppy

    BlackFly Electric Ultralight

    Openers Blackfly "Ultralight" shown at Oshkosh is apparently going on sale soon. (weeks?) Seems more like a giant drone than a plane, and CBS news report this weekend is convinced it is a flying car. https://news.yahoo.com/taking-flying-car-test-drive-134641018.html I don't know how much...
  9. n3puppy

    The Lazair Ultralight

    Calculated Thirty eight Fox 35's required, each swinging a 10x6 prop. 38 ten inch props plus clearance will fit on Lazair 36 ft wing span. :)
  10. n3puppy

    Bosch Points Ignition to CDI Conversion?

    One thing to ask if you get ahold of Steve - can't remember, but seems like there may be a preferred place to have the stator when doing all the TDC trial and error. Bolts in the slots. - full advance, full retard, in the middle? Would think there is a preferred starting spot so when you do...
  11. n3puppy

    Bosch Points Ignition to CDI Conversion?

    First things first - measure the diameter of the magnets on both flywheels to be sure they are close. (Coils on stator clear magnets. ) Long time ago I helped a friend do an Airscrew conversion on a 277. He bought the kit and did it himself. STRICTLY FROM MEMORY -long story short You want...
  12. n3puppy

    Airplane Wanted Wanted - Quickie Q1 Project

    Like I said not going to pollute 1bad88's want ad explaining two stoke vs 4 stroke operation. Have nothing to prove already know. Start a thread if you want to learn... BUT since you asked - A 11.5cr Rotax 670 with dual 40mm carbs dynoed 26.5hp @ 3500rpm 26.5hp is NOT double the [email protected]
  13. n3puppy

    503 CHT rings???

    I don't remember seeing official Rotax guidance on the crush washer BUT The CHT sensor manufacturers typically say to remove the crush washer and the CHT ring replaces it. They like the ring in contact with the head for best temp readings. With both the washer and CHT - the plug will sit...
  14. n3puppy

    Airplane Wanted Wanted - Quickie Q1 Project

    All things equal (CC, Rpm, CR, Etc) Two stokes will not make twice the Hp of four strokes. No need to further pollute 1BAD88's Want ad for a Quickie project with unrelated motor discussions. Start a new thread in the 2-stroke section and we can discuss the common sense scientific reasons why...
  15. n3puppy

    617/618UL Big Bore Option

    You should delete that calculator from your bookmarks- it has been wrong for 10+ years Not rounding error - Somebody coded the formulas for mm to inch conversion wrong Use your excel sheet - 78x68= 649.85728995097 like all the calculators I showed (649.86) 649.86 rounds to 649.9 - NOT 650.1...
  16. n3puppy

    617/618UL Big Bore Option

    He is talking about the fact 78x68 does not seem equal 650.1 cc As he says it is "under 650" cc Here are some calculators that give different results than whatever math you are using. 1) 78x68=649.86cc https://performancetrends.com/Calculators/Engine-Displacement/Engine-Displacement.php 2)...
  17. n3puppy

    Mosquito Harness 2 Stroke

    Is that Mosquito the one with the Radne Raket engine? If so - the electric start models come with a automatic decompression valve instead of the manual button one. They sell the complete kit for the auto valve.
  18. n3puppy

    Engine identification

    Based on the ignition coils and damping box, seems a points engine. That would mean 462 or 532. Black cylinders like a 462, but anybody could have painted it All the 462's I've seen had the coils mounted over the recoil assembly. Not between the carbs like this one has. Kinda narrows it down...
  19. n3puppy

    converting Rotax 503 from fan cooled to free air???

    I have personally never seen one cut that way. I imagine you would need to cut in a way that keeps any housing mounting bolts near the Recoil for strength. Would also seem a good idea to fashion some type of cover for the area where the fan belt traveled to keep dirt and other stuff from...
  20. n3puppy

    converting Rotax 503 from fan cooled to free air???

    RV7- Do you have any photos of that Extractor Shroud install ? Sounds very interesting - would like to see how it bends around to get close to the prop.
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