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  1. TiPi

    B&S 49-series (810cm3/49ci) - TiPi's conversion for aircraft use

    April 2024: not the numbers I'm chasing ☹️ I had it running again and today did a WOT run for about 4 minutes. The final rpm as measured with the external photo tach is very disappointing: 3,365 which translates to 28hp (30hp at 3,600rpm). No improvement on the OEM configuration!!! I haven't...
  2. TiPi

    Industrial engine options for Part 103

    There is no metal-metal contact, these thrust bearings run like the mains & big ends as hydro-dynamic bearing. The oil film is keeping the surfaces apart. I have an unofficial statement from B&S that the max allowable axial load on the 49 is roughly 1800N eg 2-3x the thrust force of the prop.
  3. TiPi

    Industrial engine options for Part 103

    there would be locations and times where you only have to go outside to get a 30-50kts wind. I might try that here, we get some steady 20-25kts winds at times. Just have to modify the test stand to measure thrust as well. I have a prop that I could use if it is big enough (built for a Kohler CH750).
  4. TiPi

    Industrial engine options for Part 103

    Rusty, I think you can forget the "single cylinder industrial engine" for your criteria. They will be at over 200% of their design power level and will not be reliable enough to take flying. As has been pointed out already, heat rejection is one issue and the other is the case and cover itself...
  5. TiPi

    Formula-I?

    Thanks Hot Wings, what I had in mind is the whole lower table for the one hp choice eg so that you can see what speed is achieveable with that hp at the different G-loads and what the stalling speed is. That would give you the approx safety margin in the turns. Playing with the hp and wing...
  6. TiPi

    Formula-I?

    wouldn't it be more useful to display the "achieveable speed" at a given hp (eg 35hp) and the stalling speed at the different G-loads?
  7. TiPi

    Passive Variable Pitch Propeller

    Hoffman has been making mechanical variable pitch props for a long time. My first flights were in an Schleicher ASK 16 motor glider, Limbach engine and Hoffman 3-position prop. They also make a 2-position (take-off/feathered). The propeller HO-V 62R() is a two bladed lightweight propeller with...
  8. TiPi

    Direct drive propeller (Mz34)?

    You are in a torsional vibration scenario for the belts to be chewed up this fast. So you need to look into what causes this harmonic TV and change what you can to move it outside your rpm range. Most likely a lighter prop and maybe a heavier flywheel, or both. Not much else you can change on...
  9. TiPi

    Harbor Freight Predator 670 V-Twin Horsepower tests

    Thanks fo the tips. I have 2 wide-band O2 sensors installed, with a change-over switch between L & R (and the signal output from the AEM is logged in the MGL Xtreme). I couldn't run the engine long enough to get any useful data due to an oil leak. Next run I should be able to get that all logged...
  10. TiPi

    Harbor Freight Predator 670 V-Twin Horsepower tests

    I haven’t had much luck yet with my modified Nikki. I opened up the venturi from 22mm to 23mm and the engine isn’t running well yet. I have another 28mm carby to try and then the BIG 32mm from a 1000cm3 Generac engine. Both of them have idle mixture adjustments, the OEM is fixed.
  11. TiPi

    Harbor Freight Predator 670 V-Twin Horsepower tests

    Is it possible that you increased the LSA by around 20deg? That’s massive. It should be around 108 to 112 deg
  12. TiPi

    Formula-I?

    Luciole is very limited in weight, can only have a stripped-down 38 (627cm3). SD-1 has a FWF weight limit of 40kg, the 1000cm3 engine is going to be heavier than that (FWF limit is 40kg, not engine weight). PIK-26 has been flying with the 2CV engine and is probably the only one of these 3 models...
  13. TiPi

    Milling machine/lathe options

    Agree, installed a 2-axis one on my mill and now I'm only stuffing up 50% of the time☹️ They are a great help, especially when locating holes across a work piece and to mark & drill the holes on the test club/prop flange/flywheel etc.
  14. TiPi

    Milling machine/lathe options

    I treated myself to a Sieg SX2.7L mill and a Sieg SC10 lathe a couple of years ago. They are also sold under different brands all over the world. The lathe can handle 305mm dia (12") and 700mm long (27") with a drive power of 1.5kW. The mill has a 750W motor, table X-axis travel of 500mm and...
  15. TiPi

    Universal electronic ignition options?

    it looks like that is the average current the primary circuit draws to charge, depending on no of cylinders, rpm and dwell time the average power will be lower than that.
  16. TiPi

    Universal electronic ignition options?

    This is a graph of the spark energy for CDI and conventional (induction) ignition systems at a system draw of 8A. The minimum spark enery for cold start and lean conditions is around 30mJ. The CDI would need around 3A to achieve that level of energy.
  17. TiPi

    Harbor Freight Predator 670 V-Twin Horsepower tests

    KISS - IMHO, Arduino is not protected well enough to work alongside HV wiring, they can be quite sensitive to EMF and other stray voltages. A large portion of the cost of the "established" hardware is going towards EMF protection and testing. You will still need a good quality coil pack...
  18. TiPi

    Universal electronic ignition options?

    With a re-drive, you will need some minimum rotational inertia on the crank. The prop doesn't count much as it is coupled through a "soft" connection. It will run like s**t at low rpm and most likely damage the belt. The lightest flywheel would be an alu disc with a steel ring (or lead-filled...
  19. TiPi

    Universal electronic ignition options?

    I would be interested in seeing some comparison of the spark intensity (energy) and voltage (gap width) of the Rcxel with the magneto. "Very low power draw" means very low spark energy. They might be ok for our engines but you need some minimum spark energy for consistent ignition of the mixture...
  20. TiPi

    Universal electronic ignition options?

    Another option is PVL, a German company that makes ignition modules, alternators and rectifier/regulators for kart and other small engines: https://www.pvl.de/en/products/electronic-electrical-engineering/
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