Originally Posted by
jymster
Andrea, the other issue you will most likely have with the IL300 is that it will not run successfully inverted, at least in my experience. I know at least two people who have tried, both with the engine inverted in Tiger Moths, and neither had much success it getting the engine to run properly inverted. Hence the reason why I plan to put mine in a Gypsy Moth, upright. You might have better luck installing it upright with a reduction drive that puts the prop drive inline with the cylinder heads, so the engine can fit inside the cowl. Much like the full size inline aircraft do (e.g. P-51). You can then also swing a bigger multi-bladed scale prop. Just my two cents worth.
jymster, I did take several measurements on a set of high(ish) resolution 3-views and compared them to the drawings of the engine in the owner's manual, obviously scaling the engine so that it is at the correct scale size. It seems like there's a little bit more space if I mount the engine upright in the Re 2005, but even if I do that I'll have to move the engine back some 10cm to 15cm (4" to 6") away from the prop, hence the need for a rather long and most likely supported prop extension. I'll certainly build a mockup of the nose to investigate the matter and determine the exact engine position before the actual construction begins. Does anyone have experience with long prop extensions? What would be the maximum safe unsupported length?
For sure I'd prefer to mount the engine upright anyway (why does the text editor always want to write "Mount" with a capital letter?), as it makes flooding less likely and would ease the oiling of the valvetrain before each flight.
I thought about the reduction drive option, but came to the conclusion that it's a much higher risk option: with a prop extension all one has to worry about is to add a properly supported ball bearing at the front. The engine takes care of the radial support at the rear end and also provides longitudinal support (i.e. it takes all of the prop thrust). A reduction drive (be it gear or belt) would need a completely independent prop shaft, which would require a much more capable support system able to take axial, radial and (possibly) tilting loads. I'd love to do it, but for now I'll pass...
The 1:5 scale prop for that plane would be a 24" 3 blade prop. I know that the engine can spin a 20" 2 blade, so a 18" 3 blade should be doable. Perhaps after some experimentation and when the engine is fully broken in it may be possible to switch to a 20" 3 blade. And the scale spinner would be 6" in diameter, so perhaps it may cover a little bit of the prop and give a small rpm boost. I've never used large prop spinners, so I'm not sure what to expect in that regard. Not a scale prop, but not too far either IMHO.
Just a little question for anyone willing to answer: the serial number in my Il-300 seems really low (less than 170). The engine has been available since 2006, so I was expecting something above 1000. 170 engines in 9 years mean what, less than 20 engines per year worldwide? I know these engines do not sell in large numbers, but I was expecting a little more...
My FR5-300 has a serial number close to 2000. True, it's been on sale since the mid '80s, but that figure indicates an average of 100 engines per year worldwide. Perhaps my Il-300 was stocked by the importer a long time ago and sold only now? Does anyone have any info about other serial numbers to compare (doesn't need to be the exact number, just an idea of what kind of figure it is)? No real need for this, it's just that I'm curious...
Andrea.