Oddities

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Oddities

Postby Ken McClenahan » Wed Oct 12, 2011 10:51 am

After over 60 years of flying model airplanes, I have accumulated all kinds of engines and engine parts and when I look at them I keep finding all kinds of oddities and have no idea how I got most of them.

Back in the early 50s a neighbor kid got a used glow conversion side port Gwin Aero 35 that was eventually passed on to me. I ran it and found that it got a 10x6 prop all the way up to a whopping 3,000 rpm. The performance was so bad that I threw the engine away but I kept the glow plug, which happens to be a O&R plug with a 3/8" diameter thread.

I have a Sky Fury 0.049 glow head even through I have never owned a Sky Fury.

There was a Collecto in the Denver area last month so I handed four engines (a first version Wen Mac, a Thermal Hopper with almost no running time, a David Andersen Mark III 15, and a long shaft Fox 59) over to a friend who was attending to see if he could sell them, but there was no interest in any of them. When I got the engines back I was looking at the Fox and found that the needle valve extension was on the right side right behind the exhaiust port. I got this engine from the original owner back in about 1952 and have never run it. Thinking that if anyone ever ran the engine they would not like burning their fingers while trying to adjust the needle, I decicded to turn the spray bar around. This turned out to not be an easy project because the spray bar was made out of round brass bar stock instead of hex stock so there is no way to hold onto the spray bar body except with a pair of pliers. Having 60 year old castor oil on the threads did not make it an easy thing to turn the nut. When I got got the spray bar out I checked the thread on the spray bar with a thread pitch gage and found that the thread is a 10-64 thread! Apparently the entire sray bar including cutting the threads was done on a lathe.
Ken McClenahan
 
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Postby Jim Thomerson » Wed Oct 12, 2011 2:38 pm

I'm pretty sure the Fox needle bodies, and needles, were made on an automatic screw machine. It is kind of a specialized lathe which is programed to do several operations to a piece of metal, cut it off, and then load another piece and do the same. Kind of like turret lathes which have several tools on a rotating head which come into use in sequence. This was all done mechanically before computers.
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parts

Postby Brian McCarthy » Thu Dec 22, 2011 10:50 am

Hi Ken, I have an old '50s KB19 (pre-Greenhead)motor, minus its 4screw backplate, -unobtainable in the U.K. If you happen to one in bottom of your trash bin! maybe we could make contact?....Brian.
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Oddities

Postby Ken McClenahan » Thu Dec 22, 2011 8:40 pm

Hi Brian,

I gave away all of my K&Bs except for a series 64 35 over 40 years ago and I never had a spare backplate for a 19. If I were faced with your problem I would just make one out of bar stock (I have a Unimat).

The backplates for the white head and green head 19 and 23 are all identical if that helps. The part number is 19-5 (I have the instruction
leaflets).

Ken
Ken McClenahan
 
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Location: Lone Tree, CO

Postby Brian McCarthy » Fri Dec 23, 2011 1:17 pm

Hi Ken,
thanks for note, yes thought of that route, -may be able to cobble something together without a Lathe. Have a rebuilt running KB23, had 19 running on 'borrowed' backplate but Motor doesn't have great compession
threw out more oil than smoke!, so poss' needs more work?
I love the old American motors of my youth especially K&Bs, -have a few of them now. Many thanks......Brian.
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Oddities

Postby Ken McClenahan » Fri Dec 23, 2011 8:55 pm

Hi Brian,

The K&B 19 needs lots of castor oil (say at least 20%). fairly high nitro fuel (I used to use K&B 1000), and a 9 X 4 prop. It wants to run up around 15,000 rpm.

Ken
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Postby gossie » Sat Dec 24, 2011 4:35 pm

FWIW I mix my own fuel for both K&B 19 and 35 Greenheads.

50% Methanol, 25% Nitromethane, 25% Castor oil.

9X4 APC works perfectly on the 19 and 10X5 APC on the 35.
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Oddities

Postby Ken McClenahan » Sat Dec 24, 2011 8:24 pm

As an after thougth it did occurr to me that I only used the K&B 19 and 23 for free flight while using a pen bladder tank and racing jets instead of the stock needle valve assembly. I also ended up using Fox Hi Nitro fuel (god only knows how much nitro). A 9 X 5 prop might work better for control line when using a suction fuel system.

The 9 X 4 props I used were tornado nylon (this was back in the 50s).

I used 10 X 5 Tornado Plasticote props on the GH 35s (the perfect prop). We did ROG with a 20 second engine run for free flight back then and that combiantion would put a Harry C way over a 1000 feet up even where I live at over 5,000 feet altitude.
Ken McClenahan
 
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K&B Fuels

Postby Brian McCarthy » Tue Dec 27, 2011 8:37 am

Hi Ken / Gossie,
thanks for tips on Fuels, wer'e fairly limited with only a couple of off the shelf suppliers, almost impossible to do home brew as certain products are unobtainable to private buyers. I run Model Technics 'Castor Straight' -20%Castor with either 5 or 10% Nitro /Methonol. 15%+Nitro mix are available but only with the synthetic oils. All my motors inc' the more modern seem happy on 10%,- expensive -at £15-$23.00 Gallon, Nitro IF obtainable is listed at $44.00 -1/2 Gallon.
I only fly C/Line Glo' Engined stuff, with a bunch of like minded old Guys mostly 60s+ (me) -meet Wed's-just for fun.....Brian.
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