Author Topic: O.K. 15/19 (Read 2781 times)

rustler · « **on:** March 24, 2011, 11:17:09 AM »

The spraybar on these engines appears to be a press fit. To remove, which way do you push it? Does the threaded part pass through the venturi or the fuel nipple? Just like to make sure.

FLOYD CARTER · « **Reply #1 on:** March 24, 2011, 02:51:33 PM »

If these are made like the OK Cubs, the press-fit N.V. body can be pushed out with pressure on the side that the fuel line is attached. Generally, they aren't removed unless damaged.

F.C.

Steve Helmick · « **Reply #2 on:** March 24, 2011, 07:54:37 PM »

Oh, it was a .14, not a .15, Ian. But they made power like .09's, so it's not really important.

Back in my combat days (early/mid '60's) I always wanted an OK Cub .35 powered Voodoo to set in my pit area. The idea may have been to seem a "Rube", and catch my opponents unaware, but I'm no longer sure. Luckily, I never had the money to actually carry out this plan, and I will escape this world having only owned one OK Cub, an .049B from the EZ Peezy assmbly kit. What a POS!

Steve

Bill Adair · « **Reply #3 on:** March 24, 2011, 08:16:23 PM »

I have a couple of NOS (New Old Stock) Cub .049 spray bars, and a case with no spray bar installed. Both spray bars have a larger diameter shoulder on the fuel nipple end. That would lead me to believe that they are pressed in from that side.

If I'm not mistaken, that means that you would want to press it out from the threaded end.

I've been told that the thread is 5-44, but haven't been able to find a thread gage that has that fine a pitch.

Bill

rustler · « **Reply #4 on:** March 25, 2011, 12:39:04 AM »

Thanks everybody. I assumed one wouldn't push the thread back through the venturi, but thought I'd better check.

Floyd/Steve/Bill - I've come to appreciate the O.K. series engines. The 15 (or .149?) in question has the blunt ended O.K. needle which I find hard to set, - seems like 1/16 of a turn from cutting lean to cutting rich! It's about to be replaced with an O.S. 10 needle assy.
Power? On 10% nitro my Perky with this engine does an exact 60mph. A very civilised little beast. Done nicely in pseudo-U.S. trainer colours, e.g. wrong no. of red/white stripes on the fin. (Photo maybe when I get photos sorted).

A Rube? Can guess what it means. Did this with a kit Veron Combateer, fixed wheel u/c included, when we were testing the Rivers Arrow prototypes. We flew the rounds r.o.g. just to compound the image and lull the opposition into a false sense of security, and then surprised everybody, blasting our way right through to the final! By then it was a bag of torn tissue and I lost, but what a fun experience.

Good grief. Just realised we have two opinions, one says push threaded end, the other says the fuel end. Back to the dwg. board.

Bill Adair · « **Reply #5 on:** March 25, 2011, 01:07:33 AM »

Ian,

The OK Cubs from .049 to .19 all used the same miserable needle valve I believe! No taper to speak of, and very course threads compared to other 1/2A engines of the period (44 tpi vs 72 tpi).

I picked up some precision nva's (128 tpi) from Hank Nystrom at Texas Timers to replace mine, but haven't got around to that yet. I did test fit one, and it is slightly smaller in diameter than the Cub .049 spray bar opening. J-B Weld should take care of that, and hopefully there is enough slop in the hole to allow the needle to be angled back a few degrees from the spinning prop. If not, a slight adjustment with a needle file should do the trick.

texastimers dot com

Bill

Dan Bregar · « **Reply #6 on:** March 25, 2011, 06:04:48 PM »

Steve

Good strategy ! You certainly would "have seemed the Rube" with that combo. LOL !!

And you have one more thing to be grateful for. The fact that you only owned one OK cub !

Andrew Tinsley · « **Reply #7 on:** March 26, 2011, 07:29:53 AM »

Don't know what people have against OK Cubs. They provide hours of happy fiddling trying to get them to run reliably with a modicum of power. You can get this enjoyment for not much money too! Mind you, I have not yet cracked the problem of getting them to fly. Yet more hours of unadulterated joy to come!

Regards,

Andrew.

Dan Bregar · « **Reply #8 on:** March 27, 2011, 03:07:25 PM »

Andrew

Sounds like you have a good understanding of the OK Cub !

Jim Kraft · « **Reply #9 on:** March 29, 2011, 09:10:09 PM »

I have an .049, an .074, and a .19, and they all run great. Not great power houses, but do "OK".

dennis lipsett · « **Reply #10 on:** March 30, 2011, 07:49:06 AM »

I'm always amazed at the comments of never getting an OK cub engine to either run or to fly one. Surely I and every other 9 year old kid who had them and flew them were not some sort of genius. I had quite a few of them in my youth and flew a lot on scientific and Enterprise models with them. Francisco Blue Blazer and Cox red can fuel were the norm. The needle valves wern't good and we learned to change the tip to a more pointed end, and most of us used Fireball hot plugs instead of Cub.I still remember a few models like the Sterling spacemaster with a Cub 074 on it. It must have made some sort of impression on me if I still remember it.I even used that same engine on a baby Flite Streak.
Like Cox baby Bees who a lot said that they never could get to run the cubs have an undeserved bad reputation. Granted they were not powerhouses but all of mine ran and still run. They are light duty sport engines,that won't set the world on fire but they did give some of us some pleasent memories.
dennis

Jim Kraft · « **Reply #11 on:** March 30, 2011, 01:37:27 PM »

You got that right Dennis. I don't know how many Scientific hollow logs I went through with my trusty OK Cub .049. It also did double duty in my Half Pint race car. I later put an .074 in the race car, and ran it till I broke the rod. I made a new steel rod for it, and it actually ran with it. When we were kids we use to do stuff because we didn't know you couldn't.

Dan Bregar · « **Reply #12 on:** March 30, 2011, 06:18:12 PM »

From my experience, perhaps the 074 was their best engine. I had one on a Guillows profile trainer I, and flew the snot out of it. It had almost decent power. Started and ran well on Testors 39 glow fuel. Considerably more guts than the anemic 049. Never had any trouble running them, just disappointed in the power department.

But as a twelve year old They worked OK (no pun intended) till I started learning about toy airplane engines and found higher performing engines that put a big smile on my face.

Phil Bare · « **Reply #13 on:** March 30, 2011, 06:36:55 PM »

Quote from: Jim Kraft on March 30, 2011, 01:37:27 PM

You got that right Dennis. I don't know how many Scientific hollow logs I went through with my trusty OK Cub .049. It also did double duty in my Half Pint race car. I later put an .074 in the race car, and ran it till I broke the rod. I made a new steel rod for it, and it actually ran with it. When we were kids we use to do stuff because we didn't know you couldn't.

Yep, my longest lived ever and most flown airplane was a Baby Ringmaster powered with an OK Cub .049A. It is untelling how many gallons of fuel that that little engine had put through it and unlike some other airplanes powered with other brands, it never once attempted to take off backwards. :-) I still have that engine some where, as well as an .039, a .14 and a few other OK Cubs. Even have an OK .60.

Bill Adair · « **Reply #14 on:** March 30, 2011, 07:11:50 PM »

Even though an OK Cub .049 was my very first model airplane engine (never flown), my experience with Cubs is mostly limited to a few I've put together from NOS parts. All of them have run well, and were very easy to start with one single exception.

A friends Cub .049A gave me absolute fits starting, until another friend discovered that the top tank mount screw hole had been drilled all the way through into the crank case! The engine would start and run a prime just fine, but when the tank was filled, it would die after a few seconds, and refuse to hand start again.

We never figured out if it was tank pressure, or fuel being drawn into the case via the screw hole. Plugged the hole with JB Weld, and it has run fine ever since!

All you guys with Cub .049A engines should check to be sure none of the screw holes were drilled all the way through into the case.

So far we have found three of them with the same problem, and a friend in Australia reported a fourth!

Bill

rustler · « **Reply #15 on:** March 31, 2011, 01:13:20 PM »

Err....rummm... Getting back to the original question - did we decide which end to push to get the spraybar out of an O.K. .149? Tried miking mine today to see if I could detect a shoulder either end, but too close to call.
All the O.K.'s I have tried to run have run fine. These have been 1 149, 1 19, and 2 049's.

Jim Kraft · « **Reply #16 on:** March 31, 2011, 02:49:42 PM »

I just went and checked my stash, and I have a few extra spray bars. They are knurled on the feed side, but not on the needle side. Looks to me like it should push out from the threaded side. (needle side) It is the same size on both ends, but the knurling makes the feed side about a .001" thicker.

Andrew Tinsley · « **Reply #17 on:** April 03, 2011, 04:16:14 AM »

Hello Ian,
Just checked mine and I agree with Jim, the knurling on my spare spray bar is exactly as Jim said. Mine are 0.49 Cubs, but I suspect that the smaller Cubs are all the same.
Sorry, but I was a bit tongue in cheek about running 0.49 Cubs. Once the needle is ground to a decent taper, they do start and run after a fashion, but I have never got any of mine up to Baby Bee standard and although I have flown one in a very light 1/2A plane, they really need working on to get anything near reasonable flying power. "Fit and fly" they are most certainly not, but if you are prepared to pt in some work, they can be quite nostalgic in the sense of being underpowered for the overweight models we built as kids.Brings back memories!

Regards,

Andrew.

rustler · « **Reply #18 on:** April 03, 2011, 01:56:49 PM »

Andrew et al - thanks for all the input. I'm going to assume the s/bars ae knurled as described, and give a mighty push on the threaded end. I have tried to improvise with a pair of pliars but no joy with moderate pressure, and reluctant to try more. I could "sacrifice" it but would like to keep the original just in case I need an original engine. I'm going to turn up a couple of purpose made punches.
These are unlikely ever to match a Cox, but I have very satisfactorily flown 049, 149, and 19.
Our late pal Oliver Gowing, disappointed with the performance of his Veron Nipper with Amco 0.87, substituted O.K. 19 and nearly had his arm off! I guess 20ft. lines didn't help!

Jim Kraft · « **Reply #19 on:** April 03, 2011, 02:50:03 PM »

Ian; You might just try a block of wood and a hammer. I think I did one of mine once that way. The knurling is just straight lines in line with the spray bar. You could even warm the case with a heat gun. I know I have changed them before, but it has been a while. Good luck with yours, and long live the OK Cubs.

brian thomas bennett · « **Reply #20 on:** April 03, 2011, 03:56:42 PM »

the cub 1.49 i had kept bursting into flames!!! it set fire to my kk gazelle

George · « **Reply #21 on:** April 06, 2011, 11:05:06 AM »

Adding more taper to the needle need not be complicated. I just use a file, then sandpaper on about 1/2" of the needle...works fine.

Surprisingly, I remember reading (back in the fifties) that the Cub .149 was slightly larger displacement that the K&B .15 of the day.

One thing about both the Cub .14 and the .19 is that they are LOUD!

George

dennis lipsett · « **Reply #22 on:** April 06, 2011, 06:44:33 PM »

If you know anyone who has a ball link pliars that are routinely used in Helicopters you may have an excellent tool to remove the NVA. I used mine on a cub 049 . Don't buy a pair, their $25.00 just borrow a pair from someone you know. Of course if you use ball links on your models you should not be without a good pair of ball link pliars.

Dennis

Jim Kraft · « **Reply #23 on:** April 06, 2011, 08:40:27 PM »

You got that right George. I think my OK Cub .19 and my Fox 15 slant plug, are two of the loudest engines I have. Not counting my Fox 59's and Super Cyclone.

dennis lipsett · « **Reply #24 on:** April 06, 2011, 10:34:21 PM »

Quote from: Jim Kraft on April 06, 2011, 08:40:27 PM

You got that right George. I think my OK Cub .19 and my Fox 15 slant plug, are two of the loudest engines I have. Not counting my Fox 59's and Super Cyclone.

.
Most of Duke Foxes engines were short stacks. I guess he didn't want to use any extra metal at a time when it really wasn't needed. The Cubs,Coxes et all had no stack so the noise was really right in your face,everywhere. Stacks did the service of slowing the exhaust speed down a little. usually just enough to take it below the threshold of pain.
dennis

rustler · « **Reply #25 on:** April 07, 2011, 02:25:08 PM »

Quote from: dennis lipsett on April 06, 2011, 06:44:33 PM

If you know anyone who has a ball link pliars that are routinely used in Helicopters you may have an excellent tool to remove the NVA. Dennis

Thanks Dennis. What's Ball Link Pliars?
I don't think I know anyone who flies helicopters. If I do they've kept pretty quiet about it.

dennis lipsett · « **Reply #26 on:** April 09, 2011, 02:31:24 PM »

Ian,

Ball link pliars are exactly what the name implies. They are used to put on/take off ball links on helicopters. They have a nub on one end and a slot on the other. The nub goes over the screw head. The slot behind the ball link you squeeze ant it pops off. Reverse the pliars to put them on. Heres a picture or two to explain better the i probably have,