AllTheGoodNamesAreTaken

My Feedback: (180)

I've been trying to get "into" 1/2a lately, buying a few kits and engines in an attempt to (re)explore small R/C modeling. The more I fiddle with these little Cox reedies, the more I ponder how Cox managed to sell millions of these things? There are so many things that have to be just right to get the thing to lite up and run, let alone consistanly and with consistant decent power. I don't get it....
Maybe it was more about the excitement and challenge of actually getting it to run that fueled sales.

Ok enough ranting...

So I built my DNU with a Xenalook (Ebay) reedie with SPI aka "The Stinger". I'm using one of those "SlickMounts" from JK Aerotech with the film canister tank. The first few runs with the engine were very promising. I was getting over 20K with a Cox 5x3 with the safety tips. So I head to the field.... I fill'er up, flip it with my finger a couple times and she's off... only the engine out of nowhere starts lumbering along revving up and down until the plane ceases to fly. Crap.. what went wrong? Oh, it's out of fuel... Hmmm that was only about a 20 second "flight". Ok, fill it up again, start it, nope the needle seems fine. Engine is screaming... give it a gentle toss... 10 seconds later its lumbering along again as if someone is bliping the throttle. Another 10 seconds and it quits.

Maybe my fuel is foaming? I'll try a different tank packed in foam next time.... OK, now I've got a Sullivan 1oz round tank. Now the engine is extreamly difficult to start... crap did I burn it up? So I keep flipping.... Oh yes, it fires up! Only it's running like before. High RPM to low to high.... Oh I see what's wrong, the head is loose. That's easy. Tighten it up. No change. Just surging... Maybe the head is leaking? Am I supposed to have a gasket under the glow head???
Oh, and the needlevalve, I tried puting some fuel tubing in place of the spring (which wasn't doing it's job of keeping the needle in place) and it makes it really difficult to adjust the needle. I try to adjust the the needle but the fuel tubing wont alow it to turn. I have to turn the needle a half a turn then let it spring back to make a 1/8th turn adjustment...

Someone help me before I sell off all this little stuff!

RocketRob

My Feedback: (1)

- I think you have pretty well summed up the "Glamour of 1/2A"

Remby

My Feedback: (3)

Wow, where to start. The engines run as good as any other, as long as the fuel gets in right, and the head can work to light the fuel, it will run. So, it is just the basics, and the small engines need care in the fuel, and glow heads working.
The unsteady running can be caused by a number of areas, more so (IMO) with the reedies. But, if the basic two rules above are followed, it will work. I would suggest removing the engine from the model, and bench mount it. Retry to run it, if it still lacks the wanted performance, it can be a found by stepping through the engine's parts, focus on the two basic rules. It should part of the process to know and understand what you are after, and the engine needs.
If the fuel flows right, and it has spark, it will make the rest easy.

DeviousDave

"good" 1/2A's didn't come along until the 1990's.

combatpigg

My Feedback: (3)

Jeff, the guys who have been tinkering with Cox engines for decades take it in stride, like those who are born with a handicap don't think they are handicapped. You do end up chasing problems around with those d@mn things. If I'm headed out to do a "serious day" of Cox flying, I bring a box full of engines.
If you are serious about trying 1/2A, get a AP .061, a jug of all [or mostly] castor fuel, a hand full of Nelson plugs, a couple of Hayes 2 oz tanks, a couple of Cox rubber props, some small Sullivan brand fuel line, a Berg RX, HS 65-81 [or equivalent] servos and get your hands on some 220-300-350 mah nimh packs.
Now you should be pretty well set equipment-wise for any 1/2A project with stuff that really works for the long haul. The only "Mickey Mouse" thing I have to do with the AP .061 is safety wire the muffler to the crankcase...it takes 30 seconds to do.

AllTheGoodNamesAreTaken

My Feedback: (180)

It isn't other engines or 1/2a in general that I have a problem with. I have a TeeDee .049 in my QTee that runs decent and reliably, along with a Norvel or three. I just wonder how Cox sold millions of reedies when they're such a pain in the @$$.

So.... do I NEED the copper head gasket, and what's the trick for the needle valve?

TFF

When they were selling millions they were $4 a piece bought by 12 year olds You can smell the difference of an .049 running. I think the older the engine, the better they run and the intigral tank reeds run better than the last of the breed. The ones they sell today, they are just trying to get rid of[&o].
How much nitro are you running?

icerinkdad

On the head gasket yes, YES, and Yes again... the head will not seal without a gasket and maybe more than one to get the compression right (if it is overcompressed the prop will swing back and forth and sound a little like an old sewing machine). On the needle valve what kind of engine is it exactly? The ones out of the plastic ready to fly models that do not have a built in tank often have springs that are undersize. Using a piece of fuel tubing works but it sounds very much like you have the tubing too long. It needs to be just long enough to fit with the engine running slightly rich. Take a modeling knife and slice off thin slivers till you get it to grab the needle at just the right setting... that said I always use the spring that Cox used... but have found that some of them made in the past 15 years since Estes took them over have too short a spring... that can be gently streached to fit and work.
Bob Furr
Bob

jeffie8696

Testors with the front rotary valve are my favorites. Admittedly the Cox engines are temperamental but very seldom do you see a new Baby Bee so consider the fact they have been sitting around rusting for many years .
Plenty of little tricks to make them run better.

combatpigg

My Feedback: (3)

I've run many Coxes without any head shims, it depends on the individual engine and choice of prop. The lighter the load, the more compression you can get away with. Same goes for nitro content.
For consistant runs with the SS, I threw away the spring and packed fuel tubing around the needle, then sheetmetal screwed an aluminum plate to the top of the backplate. This crushes the fuel tubing around the needle and keeps it from moving.
Some engines tend to shake the head loose, a copper gasket could help. When I go out for a day of 1/2A combat, it's to fly combat and not piddle-fart around with engine trouble. I learned that the best way to keep a head from coming off is to use more clamping force. 2 pairs of round nose pliers have been getting the job done for me for about 20-25 years, the Cox wrench routine might suit others, but how many others consider pitting 24 planes for a dozen fifteen minute matches a normal day's worth of flying?

dckrsn

So.... do I NEED the copper head gasket, and what's the trick for the needle? '

IMHO, definitly use the copper glo-head gasket.
As far as the needle valve trick, the stiff vinyl type
tubing doesn't work as well as the softer silicone tube.
Try a slightly larger (inside diameter )tube if you're already
using silicone.
Also lots of rich running can varnish the piston skirt and
cylinder lining. And then there's resetting the crank/piston
socket. There is a lot to know, and there's dozens of
posts in this forum that explain it all in detail.
I've loved these little jewels since the 60's.

dennis

My Feedback: (90)

I'm not going to get into any debate about the Cox Reed valve engines,however, I will say that as a 12 year old I was able to fly one of those every day consistantly with no problems other then keeping it clean. Also most of my peers and I were able to strip and clean and reassemble the engine in rapid order.
The point is that the more you use something the more you get used to the quirks of the thing.
As to heads and gaskets, the gasket is necessary or at best lap the face of the plug to get a clean seal, don't use cheap fuel you ought to know that you really do get what you pay for. 25% nitro is the minimum to consider running in a 1/2A and cool power in any of it's formulas is not in the running as a 1/2A fuel.You need castor oil as a lubricant, 25% is best or the leadloy cylinder will wear out faster then you can read this sentence.
Granted the better running Cox's got some TLC before we ran them and then we made sure that the cylinder was kept devarnished, which causes a lot of the problems that your having and also the ball socket was tight.Don't ever use a Mecoa or charlies goodies head adaptor.
A Cox engine is not tough to run it just requires a little forethought and getting through a rather short learning curve.
Oh and since I'm well over 60 I guess that we ran those back in the stone age when believe it or not we had just as high expectations of success and fun with the little critters.
Dennis

Mr Cox

That pretty well sums up my first flights with a BabeBee engine, as a twelve year old kid, what's not to love about that?

There are only a few things that are important and once you get those right you'll have a very nice reward. Certainly beats the no-soul electrics...

Have you tested it on a bench using a regular tank? (if not I would recommend doing that to rule out the head, reed and fuel etc.)
Sounds to me like you have a fuel draw problem. I've never tried the slick mounts myself but I would imagine that they are sensitive to vibrations, is there a regular clunk in the tank? Can't really see how that would work without the clunk jumping about and sucking air...

Jim Thomerson

Depending on who you talk to, Cox engines are (1.) fantastic jewels which start first flip, run reliably and put out lots of power; (2.) mismade pieces of junk which will not start and which run poorly if they ever do start. Most of the # 1. people will bore you with talk of their first SpaceBug or Thermal Hopper.

vicman

My Feedback: (10)

Cmon Jeff,
It's just like a TT .25 only diffrent. Oh yeah you struggle with being fast with those too[>:]

That just wasn't nice at all...I'm sorry...Sounds to me like yer giving it too mighty a toss at launch and maybe a tad rich.

PM me about next weekend we need to get togeather.[8D]

combatpigg

My Feedback: (3)

To answer the original question directly, at one time a Cox plane was just about the ultimate, most high tech toy you could give a boy. Christmas mornings in the 1960s....lots of young boys at the school yard with their fathers trying to get those planes to start and fly. I mostly remember lots of cussing, blood and parts all over the asphalt playground . I think us kids would have been better off getting BB guns and chemistry sets.

AllTheGoodNamesAreTaken

My Feedback: (180)

I think the head is leaking so I'll try adding a copper gasket tomorrow.

The SlickMount has a regular clunk. I had the same surging issues with the Sullivan tank, so if it's a fuel draw issue, it's engine related as I used two completely different fuel supply systems.

Vic,
Just be glad I don't race the Q25s. At least now you have a chance at winning a race... You better pray I don't figure this reedie thing out or you'll once again know what it feels like to loose a race to me.

Oh, and I'm not tossing it too hard. It almost flies out of my hand when I first launch it. The problem is, that power only lasts 15 seconds or so in flight.

vauxhall

I think some of you guys baffle yourselves with science. I must be unlucky, never had any issues running Cox 0.049's, apart from a couple of oldies I've bought with the reeds gummed up shut. Generally I just open the NV, prime the cylinder, hook up the battery and after a couple of flicks away they go. They're ALMOST fool proof. If all else fails, read the instruction sheet.
Have you held the model's nose tilted up before launch to make sure the Cox is drawing fuel OK?.........John

AllTheGoodNamesAreTaken

My Feedback: (180)

Ouch...[]

vicman

My Feedback: (10)

Hmmm. I think you were in the race field that day...in both classes no less

Come and git you some![>:]

I have a shim in mine.

The reason I said what I did is that when mine struggles in the air it is usually caused by a needle issue.

lousyflyer

Jeffie8696 said: "Testors with the front rotary valve are my favorites." Did you mean they were your favorite to look at? 'Cause I never saw one that would run after the prime was gone! But that old Testor's P-38 Lightning was a gorgeous plastic plane, whether it would start or not! Come to think of it, I never saw a Cox Pitts Special with the .020 PEE WEE run either. I think most of us never realized how critical a good starter battery was to starting these engines. I never saw one of those Testor's Sprite Indy cars run either. I remember struggling to start a Cox Slingshot Dragster by hand - THAT was a real pain in the hand. I heard a couple of years ago that the best way to start the dragster was off the spinning back tire of a 20" bicycle! We never thought of that one. Man, that dragster hurt like heck if it ran into your foot! All the Babe Bees I ever had ran great and started right up as long as they were clean. One little piece of sludge or trash in the fuel could ruin your day, though. I think I'd rather smell glow fuel than women's perfume!

combatpigg

My Feedback: (3)

The Testors engines were only designed to last up until about noon on Christmas day.

gcb

The average kid who would receive one of the Cox RTF's would get an airplane with tank, etc. already set up to run. The engine had not been run so the reed is not stuck, nor clogged. Add FRESH fuel (Cox), a fresh battery (just purchased) so everything was ready to go.

NEW Cox reed engines are also ready to go - unmodified. I don't think I ever bought a Cox that would not run from new.

Now when you start modifying them to run better or faster, you're on your own. If you get a Sure Start, run it on a balanced 6x3 prop, with 15%-25% nitro, 20% oil (half castor), you may never need to reach for a reset tool, and only occasionally need to replace the standard glow plug.

And never, ever expect it to out perform a 40-50 year newer designed engine...let alone an .061.

It's just an engine, not a miracle engine...

Of course opinions vary...just as engines do.

George

Clay Walters

As a kid in the 1960's the Cox Baby Bees, Golden Bees, and the later Black Widows could all be tempermental at first. But once a few tanks were run thru and needle valves set we just burned up 1 gallon of K&B 1000 after another. Every one of them (& .010 and .020's too) started good, waned somewhere around mid-tank, sputtered a little and then finished out strong and ever stronger with a fantastic surge right at the end of the tank. Heck, its how you knew you were about to land.

I've run two SureStarts on the Slickmount and they do the same thing. When one runs without quiting its a looong run. But, they've yet to be airborne so I understand things may be different then.

Regards,

Clay

WINANS

I find it kind of funny that some folks have such a tough time with half-A's. What I know is that me and my frineds, from the ages of ~9 to 19, were able to have one heck of a time flying half-A everything. It was just such fun, and rewarding, and not all that tough to do. What an experience that was for me - Control line, free flight, R/C, and a hundred different models.

Maybe expectations have changed, but peoples capabilites have not really changed.

Scott