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Old Jan 10, 2013, 10:45 AM
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Originally Posted by RknRusty View Post
The KK needles fit the red backplate from the Cox Black Stuka engine. The needles even look the same. I also have an unknown white Cox backplate with the same threads. I screwed one in a couple of days ago just to see. I was thinking about making a remote NV.

Hank Nystrom at Texastimers sells a 128tpi NV that supposedly presses into a Norvel. I've been meaning to compare the measurements but haven't gotten around to it. He's still closed until Jan 11 or so. I think it would be easiest to just chuck the venturi in the box and put the new NV right through the holes in the engine. Bore them to fit and JB Weld it in place. They are splined too, so it should fit nice and tight. It might go into the hole where the old NV is. That way you'd still have the screen. A screen is good for me.
Interesting info..thank you.
I had made the same observations that you describe,, however I asked to double check, as I have no product engines on hand, before ordering.
Apparently that was my mistake.
Wonder what Bernie was on about then ?
I suspect removing the Norvel venturi insert entirely would lead to a very small prop and tricky starting. That's a Big hole.
Have seen bespoke diy plastic bathtub inserts.. presumably to address that problem.
Remote NV assembly is a helluva good idea.
Despite being teeny engines these things can still bite hard.
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Old Jan 10, 2013, 01:41 PM
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Originally Posted by Bare View Post
... Despite being teeny engines these things can still bite hard.
I cussed.
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The coolest looking cut I ever had. The tips of a Master Airscrew are kinda sharp. I'm glad it wasn't an APC.
Actually an MP Jet .061 did that. Its NV is Stupid close to the prop! I could calculate how long my thumb was in the blades if I knew the RPMs.
The black speckles are spray paint.
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Old Jan 10, 2013, 05:13 PM
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Hmm

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Originally Posted by aspeed View Post
I made some brass sleeve bushings for a few worn out Baby Bees that wouldn't run reliably any more. The cranks would rock up and down after a while, and we practised a lot with the mouse racing. Talk about wasting time with the bushings, you get the tolerances just right and lapped, press it in the crankcase with a .001 interferance fit, and the you have to lap it again. We had to run the B Bee though, them's the rules. We used to drill out the backplate hole to go faster, and then you would need an extra pitstop etc.
Phosphor Bronze , as long as you get the right one ..

I used to rebush a lot of my worn rods , as well as cases for the crank ..

Aaaaah the good old days ...

In races where fuel economy counts , having fuel spray out the front race was bad .. 2 tricks , one was to machine a very slight ring on the inside just in front of the front race and then run a small channel back to the carb as a fuel return ..
[ Path of least resistance n all ]

2nd way was with a small phosphor bronze rings pressed in [ machined space ] behind the front bearing to act as a seal [ needed to be lapped for a sweet fit - not tight enough to slow the motor , not so lose as to not stop the fuel spraying out the front race ]

If you wanted , you could machine a TD case , so as to fit a PB bush near the web and at the front for a twin PB bush set up .. Bushes wear , you replace them .. Threading them into the case may be possible rather than a press fit .

Though that would need serious machining skill to fit correctly [ threaded bushes ] , Press fit is usually the go , but makes removal [ sometimes tricky ]
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Old Jan 10, 2013, 05:53 PM
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I never wore out a front intake plain bearing case, just the reedies. I have had a few motors that leaked a lot out of the front. A Stels .049 which I had to make a new bushing(when drilling out the case, I found out there was actually one in made of aluminum.) I have a couple of MDS BB .15's that leak like crazy. I was told that is good as it lubes the front bearing, it is a piped motor, but they are really bad. Also a Thunder Tiger .07. Really pretty motor, but really sloppy crank fit. I soldered that bearing, and oddly enough it is pretty good now.
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Old Jan 10, 2013, 05:57 PM
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Old, are you a machinist? Do you have the equipment to do all the measuring and fitting in your shop?
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Old Jan 10, 2013, 08:08 PM
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Machinist = Yeah

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Old, are you a machinist? Do you have the equipment to do all the measuring and fitting in your shop?
Used to have a lathe - used to do lots of stuff ..

I would love to own another lathe .. When you have a lathe its , naaa that can wait ! you dont have a lathe , and its , Oh maaaan ! I need a lathe !

I have a ETA 15 needing a new rear intake disc + a head to complete [ man I need a lathe ] Some Super tigers needing some TLC , + I could use a lathe for doing some trick Flashlight Mods .
Problem is it needs a 32mm Bore [ Spindle ] so I can make crank shafts ...
I need some new cranks for some empty cases I have ...
Was thinking 12mm crank for a Gold Top Taipan 2.5 ... and some other cases I have , PITA making cranks , but been there done that .

Too many things needing money ATM , so might be another year before I can seriously contemplate another lathe .
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Old Jan 10, 2013, 08:28 PM
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Did you press in the crankpins, or grind/machine it?
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Old Jan 10, 2013, 09:19 PM
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Machine

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Did you press in the crankpins, or grind/machine it?
I machined the crank pin on cranks I made , would be easy enough to do a pressed in pin , but since I had to machine from bar , why not machine the crank pin .. [ was a little time consuming ]
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Old Jan 12, 2013, 01:17 AM
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The problem is worn ovility in the crank case causing air intrusion from the front of the case, exacerbated as the case temperature increases.
The steel crank might appear to be wear free, but it must be matched to a new aluminium case.
Back in the 20th century we humble balsa bashers would simply replace a motor like this, perhaps keeping your favorite matched piston/cylinder for another day (i.e. playground dirt plough).
Back then our LHS carried all sorts of parts and tools for these motors.
Now it's the 21st century and we have better stuff that doesn't break down every ten minutes.
They don't build them like they used to.
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Old Jan 12, 2013, 10:02 PM
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Back to the Li'l Satan for a moment. I took it out with its newly rebuilt Tee Dee and it screams around the circle very nicely with a 5-1/4x3 MA prop. The video is uploading now so I'll post it in the morning. It flies really well but a bit too stable with large loops. I'll remove a tad of nose weight before I try it again.

I took my Newest Norvel powered Baby Flite Streak for it's maiden and got some good videos of both planes. I was anxious to maiden the Streak so I switched planes after testing the Satan.

Here is the Satan video. Full screen is enabled.
Lil Satan good running Tee Dee (0 min 0 sec)


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Old Jan 13, 2013, 09:34 AM
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Runs nice and clean. What did you end up doing for the 'rebuild'?
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Old Jan 13, 2013, 10:56 AM
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It's a whole 'nother engine, a lightly used Tee Dee .049. I polished the crank and put my last NIP Cox #4 cylinder/piston set on it and broke it in with about 8 ounces of fuel. I also bored the venturi out from .125" to .1406" and polished it, and put the screen back on. I'm a firm believer in screens for CL stunt planes. Still with the KK fine thread NV and a pressure bladder.
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Old Jan 13, 2013, 07:49 PM
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Originally Posted by RknRusty View Post
I cussed.
Attachment 5437457
The coolest looking cut I ever had. The tips of a Master Airscrew are kinda sharp. I'm glad it wasn't an APC.
Actually an MP Jet .061 did that. Its NV is Stupid close to the prop! I could calculate how long my thumb was in the blades if I knew the RPMs.
The black speckles are spray paint.
Don't let any kids see it, they'll all want a tattoo like that. You'll start a new craze!
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Old Jan 13, 2013, 09:26 PM
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Wandering a bit from where you started, cut off another 1/4" from the prop, the tee dee didn't sound like it was turning anywhere near 20k in the video.
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Old Jan 13, 2013, 09:54 PM
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I figure 18,000 rpm on the ground with my trusty little pitch pipe. It is a D. Likely hits 20,000 in the air. I can't check that unless the microphone is in the circle.
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