jmercer52

My Feedback: (14)

One of my buddys just gave me a new Cox engine, but I can't tell what size or style it is. I have lots of .049's, but this one is either a .074 or a .090. It has a beam mount style crankcase with a "rear" reed valve. It also has a "rear" mounted RC carb and a muffler that slants out to the right side.
The head is not like a regular Cox, it has a replacable short reach glow plug in it, although it still has the two slots that you can use to tighten the head down with... if i had the wrench ;-(
I would also like to know what size prop to use on it. I ran it on my test stand with a 7x6 prop/15% fuel. It ran ok, but I think it needs a little smaller prop and a little more nitro. It just didn't sound like it running at full power.
Thanks for any help!
Danny

Tim Wiltse-RCU

Danny,

What you have is a Cox Queen Bee .074. Not that you want to hear this but it is the biggest piece of junk Cox made. It will trun a 6x3 or 6x4 prop as good as a healthy Cox Black Widow or Medallion. It should use just regular short glow plugs or you can use Cox .09 TeeDee or Medallion glow heads. Over all it's best to leave this engine cleaned up and sitting on the display shelf.

LAter,
Tim

DICKEYBIRD

What you have there is a Queen Bee .074. They usually have a 7x3.5 Cox prop but these are scarce nowadays. It is said they have the power of a Tee Dee with twice the weight.

I have one and hope to someday tweak it for a bigger prop and make it useful.

jmercer52

My Feedback: (14)

What's so bad about it? It seemed to run ok with me, but I just figured that the prop was too big and I know that Cox and most small engines need more nitro to run good... Other than the fact that it does weigh a bunch!
Does it have any bad habbits... like throwing a rod or something...? It a real nice looking engine and I really like the fact that it has a carb on it, it even seemed to idle down pretty good, if you call 5000rpm an idle. But I know what to expect from small engines, I've been using .049's for about 15 years on my Gentle Lady and small park flyers.
As a compairson, it ran and idled as good as any of my throttled .049 Cox or Norvel engines, but it is heavier. I think I'm going to try to find a 7x4 prop and see if I can find a small can of 25% Cox fuel somewhere and give it another try.
Thanks for the info on the type of engine it is... I thought it was an .09...
Danny

Big Al-RCU

Danny, there’s nothing BAD about it, especially considering what you have invested in it, other than it is a bit heavy and will never develop the output that you might expect from that size engine. My son and I had one in a low wing sport plane (Spacewalker I think, or something similar). Looked like a perfect combo. Problem was, it was a dog in the air. It’s favorite flight mode was to mush around nose high on the backside of the power curve. Not good.

Our engine had some slop in the piston/rod ball joint. Taking that slop out did make a noticeable improvement. Unfortunately there isn’t a proper staking tool available for the .074. We were lucky to have a watchmakers staking set available and after 15 minutes and a ‘thousand’ (more or less) taps with a flat nose punch and rotating the piston between taps, were able to get it tight. I would not advise doing this freehand tho, probably better to make a special punch.

If you want to fly it, (and why not?) then treat it as an ‘antique engine’ and put it in a suitable airframe. That would be a slow flying plane with a light wing loading. Might be lots of fun. Just don’t expect it to be comparable to the current crop of engines.

Al Lenz

Clean

Check this link http://www.mh-aerotools.de/airfoils/cox_frameset.htm for a purty good reference of cox engine history. Under the Bee engines tab at the bottom of the page you should see a picture of your engine.

flyinrog

My Feedback: (1)

I've written this before, it is a quote from a cox pamphlet

"providing the same power as a competition Cox tee dee .051 the Queen Bee .074 offers modelers dependable reed valve performance, a muffler for quiet flight and complete throtttle control. the .074 reaches 16,500 rpm and smoothly idles down to 5,500 rpm with a 6 x 3 prop"

ptulmer

My Feedback: (5)

Darn it, MAN! I didn't know the QB was a reedie! Now I want one.

Danny, at 5k rpm, it won't move much air, so that's a good idle for 1/2a.

DICKEYBIRD

Hey Patrick...just think of it this way: not only is it a reedy, it would also be a great candidate for practice on that new lathe of yours. Wonder how much weight one could carve off?

Tim Wiltse-RCU

DB,

The only way he's gonig to lighten a Queen Bee is with a plasma cutter and a stick or 3 of TNT

LAter,
Tim

ptulmer

My Feedback: (5)

Well, a very intelligent man (CP) once told me that reducing the weight of an engine by removing aluminum is like getting a haircut to lose weight. (The point being most of the dead weight is in the sleeve, but who knows what you can do with a Cox cylinder...) Shoot, I wonder what a Nelson head would do for a QB? Anybody done any nice mods to one?

SGC

Doesnt the 074 cylinder have the same outside dimentions as the 09? ie its an underbored 09 cylinder. If so will an 09 cylinder screw on/ will an 09 rod fit the crankpin ? if so use an 09 piston /cylinder and get more power for less weight.
Stewart

jmercer52

My Feedback: (14)

Hey Mr. Clean, that web site address you sent was full of GREAT info, one of the best I have seen on Cox engines! Your right, it is a QB.074.. Now I wonder if SGC is right about the .09 cyl/piston interchange... I mean, hey why not get a little more power for the same weight? Anyone know if that will work?
I pulled the muffler and exhaust ring off the cyl today and it does weigh a bunch by it's self, but I figured it run cooler without it. My flying field doesn't have to worry much about noise, it's on the grounds of a deaf school and we don't bother anyone when we fly... they can't hear us.

Clean

If the stroke isn't the same from the crankshaft you won't get more punch, you'll get nothing. Larry Renger would be the person to ask about that. I originally found the link to that cox site here, don't know who posted it first just knew it was here somewhere. Thanks to Mr Google all you need to know is what you're looking for and mr Google does the rest. Glad I could help though.

combatpigg

My Feedback: (3)

I bought a QueenBee after reading a Chris Chianelli review about how great it was.......that fact alone excludes me from the "wise man club" . I'll admit to being a "wise guy". I think there is performance potential lurking with almost every engine.......except this one