Being limited by Covid quarantine resources, I clamped a 24” piece of ¾” X ¾ maple across the disconnected hub and added weights until it began to barely move: 375 – 400 grams @ 1 ft. Being that it would be difficult to imagine maintaining 2600 or 3000 rpm without needing to add more mass to...
The cooling fan on the stock 173cc engine is 6.5" in diameter and the fin height is slightly under 1". A comparable Fasco A118 has a 5.75" fan and a 1.125" wide fan and is driven @3000rpm with a 1/15 Hp motor. 746/15= 49.7watts. I'm working on way to figure the hub friction.
Not exactly. Air cooled, similar carbs and mufflers, yes, but my engine does not have a cooling fan. Why do I think they can still be comparable? The work of the cooling fan is replaced by the work necessary to drive the two preloaded tapered Timken roller bearings and hub seal that support the...
The attachment below compiles the data from the two links I mentioned at the start of the thread.
I converted the numbers and plotted them as fuel rates (g/hr) on the ordinate and power (watts) on the abscissa. A horizontal line can be drawn at any fuel rate to compare the power developed by...
I posted the wrong link in my very first post. It was missing the most important part; Appendices A, B, etc.
Here is the link I meant to send:
https://ww3.arb.ca.gov/regact/sore03/app_g.pdf
I am compiling a spreadsheet with similar units converting lbs/Hp hr to g/kW hr.
I'm thoroughly enjoying the thoroughness. Speaking of Master and Doctoral theses, I don't remember any comments on the one that I had posted in the previous thread.
I'll post it again: https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=8100&context=masters_theses
I'm making some assumptions, however, would it not usually be the case that if one was dealing with FMEP, and not friction torque, the choice in measurement units would not be Nm. I'm not sure if I have ever seen FMEP converted from kPa back to a torque in Nm for a paper, but once again I could...
Good point. I might be wrong, but I took Section 7.4 to include Figures 12 and 13. Section 7.4 talks specifically about engine motoring with 0-20W. While Figure 12 refers to only two engines, Figure 13 refers to over 30 engines. I would think that the data for motoring complete engines might be...
Along the lines of FMEP, once again it's about what a family of numbers points towards. Check out Figure 13 of this SAE paper.
https://pdfs.semanticscholar.org/f9c7/4733a470b57d42dc9d3180ef8ebad83d2656.pdf
While there is only one point close to my engine (692cc), the number for my engine @1500...
Agreement here as well. I had seen the 250g/Hphr but have made a point to shy away from single numbers and prefer a family of numbers as a general rule. There are so many allowances regarding J1349, J1995 etc. and testing without air filters and mufflers I don't really know what I am comparing...
Thanks, Brian. I guess what I am wondering is if anyone might have any numbers from tests they have conducted themselves or have references for otherwise to demonstrate that the numbers in the links above are incorrect somehow. Granted all of these engines are running rich with $9.99...
Below are a couple of links to BSFC numbers for engines with similar technology criteria and displacement per cylinder. Does anyone have any numbers that would indicate for this type and size engine that these numbers are incorrect? The first link shows a sweet spot of about 440g/kW hr.for 179cc...
