Fin 35
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Posts posted by Fin 35
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Many thanks for the replies and suggestions. I'll leave the engine as-is for now and see how it goes. If there are issues, I'll try a larger breather nipple first. Bearings are on order and I've even turned some fitting plugs, so the process will be nice and easy. My friend was thinking about putting it in a scale model but I think I've persuaded him to build a Super 60 with the aileron update - at least until he gets his 'A'. Instructors will be queuing up to buddy that one. Can't wait to test it on the bench!
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I'm refurbishing a fascinating old Enya 35 4C open rocker engine for a friend. It doesn't look like it's had much running but it's gummed up with old castor oil and the bearings are rusty, so I'm replacing them. My question is about lubrication of the rear timing gears. There doesn't appear to be a vapour path to them from the crankcase, other than through the sliding fit of the timing shaft at the rear of the crankcase. So I assume I should partially fill the rear "gearbox" casing with oil via the tappet holes. This would serve to lubricate the gears, cams and timing shaft rear ball race. Any thoughts?
I've also noticed that the crankcase breather was blocked (!) and that the hole is only 0.9mm, which seems small compared to modern engines. The rear crankshaft bearing is unshielded and the front one is shielded on its front face only. Again, the only path I can see for oil vapour to reach the front bearing is via the sliding fit of the crankshaft through the front bearing housing. It seems odd that there isn't hole, or am I missing something?
Presumably the rockers need a squirt of oil before each flight?
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The spare conrod that I ordered (before the polishing exercise) arrived today. It has the same casting/forging line as the others but it's generally a bit neater. It's tempting fate but I doubt I will ever need it.
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Just to be clear, the engine that gouged its piston was not a Saito.
Both of the Saitos I've referred to here were perfectly clean inside and out, and nicely greased for their first run. My only concern with them was the line on the conrod and I think we have cleared that up - literally!
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I didn't intend to dismantle the engine, just to remove the backplate to check for swarf. I've only started doing this recently after a bad experience with a new engine that gouged the piston very badly on the first flick with fuel in it, but that's another story.
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Thanks Paul, you inspired me to cut metal, well, file and polish it at least. First prize goes to Alan! I think I took about 0.25mm of the higher surface (although I didn't measure before/after) and then worked my way down to 1200 wet and dry and metal polish. It's not a mirror finish and there is still a slight crevice/dimple in the middle but I didn't want to push my luck.
Many thanks for all the comments. I don't think we will hear of many conrods snapping any time soon but they won't win any beauty contests either!
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I ordered the last one today! I wonder what it will look like.
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Stress and acid indigestion ?
When I run my nail over it there's a step, high on the long face, low on the short face.
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Another photo attempt...
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That was the first thing I did - disassembled one of the engines, and it looks like a crack. I was hoping it may be a casting line but its jagged and goes down each side of the rod thickness for about 1mm. New photo is not great but it gives you an idea.
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Yes, the crack is in the same position on both engines, in line with the outer radius of the crankshaft balance weight.
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I've just removed the backplate from an un-run Saito 62B, only to find a crack all the way across the conrod to a depth about 1/4 of the thickness. I have two of these engines, both new and un-run, so I looked in the other - exactly the fault! I contacted MacGregor but they were not aware of this issue and directed me back to the supplying model shop. Has anyone else seen this in 2020 vintage Saito engines?
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Nice photo of a very elegant Flyboy Roy. I like the model in the background too. I've just posted some photos of my Flyboy2, made in lock down from a spare fuselage that I couldn't bear to chuck in the bin! I've been flying it since last year and it's quite a fun little machine, with ailerons and an Enya 30 up front.
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I acquired on of these little models last October (from somebody's loft of course) and fitted some radio gear over the Christmas holiday. Having read the posts here I was expecting trouble and I was not disappointed. The Dutch roll was hilarious. For safety I hand launched it and all was well until I touched the rudder. It's essentially set up as a freeflight model with a tiny fin to give it strong spiral stability at the expense of Dutch roll damping. I had a few flights with it in that state, with the CG at about 69mm for the LE (34%). It was quite aerobatic in it's own sweet way: loops, rolls, spins, outside loops, but all a bit hairy. I have just enlarged the fin and flown it again - what a difference. The Dutch roll is all but gone and it flies like a standard aileron trainer, although I still have to be gentle with the rudder. I've moved the CG back to 75mm (37%) and that's about as far as I think it should go. Down thrust and right thrust are both about 2 deg but I've fine tuned with throttle to down elevator at 5%. It has a nice glide on deadstick and doesn't require too much trim change with speed. Engine is a sweet little Enya 25 that is still running-in. All up weight is 1.33kg which gives a hefty wing loading of 61 g/dm2. Our strip is a bit long this time of year so I've not attempted a ground takeoff, but hand lunches need to be energetic at full power with a 10x5 prop. I definitely recommend enlarging the fin - mine has a height of 190mm with and average chord of 110mm, TE the same but much reduced LE sweepback. I extended the rudder height but not its chord. Oh, and I'm using 35MHz of course
Enya 35 4C open rocker lubrication
in IC Engines
Posted
Just finished rebuilding the engine and ran it on the test stand. Started on the 2nd backward flick and ran beautifully. The forward facing glow plug is a bit exciting with a glow stick - fingers very near the prop! Now I have to give it back to its owner 🥲