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Author Topic: Suggestions for Cub .049A power.  (Read 1785 times)

Offline frank mccune

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Suggestions for Cub .049A power.
« on: January 28, 2021, 10:51:15 AM »
         Hello All:

         I was gifted two of these engines and am curious as to what airplane I should build for them.

         How well do they run for u control?

         Comments/suggestions

          Tia,

          Frank

Offline john e. holliday

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Re: Suggestions for Cub .049A power.
« Reply #1 on: January 28, 2021, 11:46:45 AM »
The OK Cub .049A I had years I flew most of the 1/2A kits available back in the late 50's and early 60's.  I even out flew a Golden Bee a club mate had on a combat wing by Consolidated.   When they came out with an ad for the .049A a couple of years ago I bought two.  Put them on a block of wood and tried to run them.  Even had some 20% nitro fuel I tried on them.  They would run the prime out and quit.  Checked the fuel lines and needle valve for leaks.   Finally got disgusted and put them away in the shop.  I still have my original in the shop some where.  Hope you have better luck with yours. D>K
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Online Ken Culbertson

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Re: Suggestions for Cub .049A power.
« Reply #2 on: January 28, 2021, 12:03:43 PM »
         Hello All:

         I was gifted two of these engines and am curious as to what airplane I should build for them.

         How well do they run for u control?

         Comments/suggestions

          Tia,

          Frank
If you can get them to start.  I never got mine to run past the prime.

Ken

I see I am not the only one!
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If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Online Larry Renger

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Re: Suggestions for Cub .049A power.
« Reply #3 on: January 28, 2021, 08:28:52 PM »
My first useable engine was a Cub and it ran just fine. I have had a few since and they all run. I even hopped one up to at least Cox Medallion standard or better. Had it on a 1/2 A Spacer at Taft and coming back from a flight a fellow modeler was flabbergasted and said “That’s a Cub?”

They can run just fine and can be hopped up with a few simple mods and really hot fuel. The compression is low, the fits tend to be loose, so they can handle the Nitro just fine. A hot battery for starting is a good thing. The best mod is to substitute the needle assembly from a Cox rtf backplate for the Cub one. (more later) Orient the exit hole about 15 deg below horizontal for optImum fuel draw.

There is a weird ledge in the port in the crankshaft that obstructs flow. I grind that smooth. I also clean up and smooth the entry to the bypass ports. If truly inspired, the crankshaft balance can be improved. With all this done you can amaze your friends with what a Cub can be.

An ideal model for a stock Cub is the 1/2A Snapper. Full pattern capable on very light lines. Not quite so good would be the Brodak 1/2A kits unless you lightened them up a lot! Perhaps a Goldberg Jumpin Bean is in the ballpark.

If all you want is to go round and round, of course all the ScientIfic and Blackhawk replicas would be fine.

The Cub needle really sucks. It pretty much works by a blunt end shutting off the fuel hole. Almost an all or nothing approach making perfect adjustment impossible. Not the standard smooth taper giving easy control of the metering. Chamfering the top of the venturi would be a good thing too.
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline john e. holliday

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Re: Suggestions for Cub .049A power.
« Reply #4 on: January 28, 2021, 08:57:36 PM »
Thanks Larry,  may have to find mine and see what can be done. D>K
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Offline Dave Hull

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Re: Suggestions for Cub .049A power.
« Reply #5 on: January 29, 2021, 12:16:04 AM »
I was never a OK Cub fan. Then a co-worker (a good friend) gifted me a couple of engines and tin box of spare parts and whatnot from his childhood. Said he was trying to get the house organized. So I proceeded to clean them all up and put some of the missing parts back on. They were looking pretty solid, so I told him how they came out. He said he regretted giving them away so I immediately offered to give them back. I walked back to my office and grabbed 'em right then.  I had hopes that the elaborate plot would get us another retread modeler and club member. Still hoping, but guess now I really need to twist his arm. Would love to see them mounted to one of his original-type models. Probably a Zig-Zag or somesuch.... although if you are going to go Musciano, ya really ort ta go with the Cyclone.

I'm not sure it is legal in the USA to hop up a Cub. I think that would fall under "indefensible acts" or something like that. But Larry does like to live dangerously....

The Divot

Offline Dane Martin

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Re: Suggestions for Cub .049A power.
« Reply #6 on: January 29, 2021, 10:32:51 AM »
Our OK Cubs run well


Offline Gregory Hammond

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Re: Suggestions for Cub .049A power.
« Reply #7 on: February 01, 2021, 01:47:48 AM »
Cub Controller by Walt Musciano :)

https://outerzone.co.uk/plan_details.asp?ID=5562


Designed for the cub way back when!

Offline kenneth cook

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Re: Suggestions for Cub .049A power.
« Reply #8 on: February 01, 2021, 04:21:14 AM »
                I love it Dane, loud little suckers. I have a .074 in my Dakota free flight and it has a note to it. If you ever had the pleasure to hear the OK .19 run, you will be surprised how loud that is.

Offline Norm Furutani

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Re: Suggestions for Cub .049A power.
« Reply #9 on: February 01, 2021, 10:39:24 AM »
I’ve been curious about the Sig Mini Zilch. See: https://sigmfg.com/collections/control-line-kits/products/sig-berkeley-mini-zilch

Cute little plane, Maybe the Cub would be an appropriate engine?

NormF 

Online Larry Renger

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Re: Suggestions for Cub .049A power.
« Reply #10 on: February 02, 2021, 07:40:11 AM »
I think the plane would be too small. It was designed for the old .020 K&B
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline bobsrc

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Re: Suggestions for Cub .049A power.
« Reply #11 on: February 04, 2021, 10:49:12 AM »
I think the plane would be too small. It was designed for the old .020 K&B

The Cub will work OK.  I flew one of the prototypes with a Babe Bee with no problems. 

Offline GallopingGhostler

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Re: Suggestions for Cub .049A power.
« Reply #12 on: February 05, 2021, 08:47:24 AM »
The Cub needle really sucks. It pretty much works by a blunt end shutting off the fuel hole. Almost an all or nothing approach making perfect adjustment impossible. Not the standard smooth taper giving easy control of the metering. Chamfering the top of the venturi would be a good thing too.

Yup, I have that problem on both of mine, the A & B. There is a bad leak around the threads of the needle. They use an odd split collar around the needle, which makes sealing with a short piece of silicon fuel line nearly impossible. The needle is very twitchy, hard to get a good consistent run.

Thanks, I think your idea of a Cox NVA from an RTF back is a good approach to try. I did that with a Testor McCoy .049 Rotomatic to fix its botched NVA (bought used off an Internet auction).

Offline Bill Adair

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Re: Suggestions for Cub .049A power.
« Reply #13 on: February 06, 2021, 08:50:03 PM »
My main complaint with the Cub .049A was the plastic tank. Mine appeared to be shrunk and distorted. The leaks around the mount screws flooded the engine while starting. Had to use an external tank and got some good runs that way.

Bill
Not a flyer (age related), but still love the hobby!

Offline Dane Martin

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Re: Suggestions for Cub .049A power.
« Reply #14 on: February 07, 2021, 10:38:53 PM »
                I love it Dane, loud little suckers. I have a .074 in my Dakota free flight and it has a note to it. If you ever had the pleasure to hear the OK .19 run, you will be surprised how loud that is.

I have lots and lots of 1/2a Cubs, up to the .099 but I don't have a .19! Now I gotta find one. Lol

Offline Dane Martin

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Re: Suggestions for Cub .049A power.
« Reply #15 on: February 07, 2021, 10:47:48 PM »
Cub Controller by Walt Musciano :)

https://outerzone.co.uk/plan_details.asp?ID=5562


Designed for the cub way back when!
I've never seen this model, but I just downloaded the plans. I gotta have one!!

Offline Wayne Collier

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Re: Suggestions for Cub .049A power.
« Reply #16 on: February 09, 2021, 01:17:28 AM »


The Cub needle really sucks. It pretty much works by a blunt end shutting off the fuel hole. Almost an all or nothing approach making perfect adjustment impossible. Not the standard smooth taper giving easy control of the metering. Chamfering the top of the venturi would be a good thing too.

So all I did was remove the needle and then got some pliers and slightly crushed the part the needle screws into. Just enough to make the needle hard to turn. Makes it easier to creep up on the sweet spot because it’s harder to turn too far. Also because of the slight bind, once it’s there it stays. Over doing this can ruin the part. If that happens, follow Larry’s advice and use a Cox needle assembly.
Wayne Collier     Northeast Texas
<><

never confuse patience with slowness never confuse motion with progress

Offline Dennis Leonhardi

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Re: Suggestions for Cub .049A power.
« Reply #17 on: February 14, 2021, 02:04:22 AM »
I had a Cob .049A on a Scientific "hollow log" back in the '50s.  Put on very large elevators and had fun doing the "Sabre Dance" with it.  The engine wasn't a "one flip starter" but ran really well.

My experience with several .049 to .099 Cubs in the '50s was (1) the good ones were usually very reliable and strong, and (2) the poor ones weren't worth wasting time on - but they were usually few and far between.  I rather suspect more recent products were of lesser quality.

Dennis
Think for yourself !  XXX might win the Nats, be an expert on designing, building, finishing, flying, tuning engines - but you might not wanna take tax advice from him.  Or consider his views on the climate to be fact ...

Offline Oldenginerod

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Re: Suggestions for Cub .049A power.
« Reply #18 on: February 16, 2021, 01:07:23 AM »
My main complaint with the Cub .049A was the plastic tank. Mine appeared to be shrunk and distorted. The leaks around the mount screws flooded the engine while starting. Had to use an external tank and got some good runs that way.

Bill
One danger with the plastic tanks is that after a few overtightenings of the tank screws, the tank compresses, requiring the screws to be tightened in further than they are supposed to be.  The upper screw is supposed to be into a blind hole, so either the screw bottoms out and can't be tightened enough to stop the tank leaking, or when you mention flooding, someone has overtightened the upper screw and punched a hole into the crankcase allowing fuel to be sucked directly into the crankcase past the screw threads.  This can be corrected by sealing the threads of the upper screw if it hasn't damaged the case too badly.  Maybe shorten the screw before it punches through.

Rod.


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