WoodCutter

My Feedback: (8)

Hello all. Even though I'm up to my ears in projects right now it's still nice to be planning some more airplanes for down the road. I'v gottwo brand new 1990's vintage cox Black Widows in boxes just crying out to get put in an airplane...
I remember using the Black Widows years ago on U/C planes but I've never run any kind of Cox on an R/C model before. I know that the fuel pickup in the tank needs to be turned to the bottom of the tank, the instructions tell me that...

The question I have is .. how well can a model be flown with a tank with no 'klunk' to follow the fuel around with. I have seen pictures on this forumshowing airplanes with golden bees with tank mounts on their noses. It seems to me that as soon as one pulls any kind of negative g's or even throws the model around at all the fuel will move away from the pickup and the motor will cut out.
Does this happen with these tank mounted motors?

I am thinking about buying a 1 oz klunk tank from Cox International and a standard backplate style mount to be able to run a more normal set-up. The .049s however are not set up to run with muffler pressure, andI didn't think they whereknown for having a good fuel draw. The last time I ran a model set up that way was with an MP Jet .061 on a mini pattern plane. (no muffler pressure tap) If I remember right I always had problems getting a consistant run. I had to set the needle sloppy rich for the launch in order to not have the run not get too lean at the end.

Now I'm sure that the Black Widow with it's own tank could just fly around in gentle circles with no fuel feed problems but truthfully I would probably get bored with doing that. I would want to be able to do some aerobatics.

I would appreciate if people with more experience with these motors could enlighten me about how they perform?

Thanks,
Robert
WoodCutter

nitroairplane

I have flown 8cc stunt tanks on rc with the pick up at the bottom.

gene6029

I fly R/C with several Cox .049s, with no problems. I have done nothing to the std pick up in the tanks. I use the Black Widow, Golden Bee, & also the Baby Bees in my models. My models loop, roll & occasionaly fly inverted with little to no problems. They will on occasion momentairily stutter, but usually keep running. I only run reedie motors, so i use the motors that have the tanks attached....Gene

DeviousDave

A guy can have a lot of fun with a simple aerobatic airplane and a Black Widow..... They are pretty peppy engines.

vicman

My Feedback: (10)

nice looking quick shot there Gene.

gene6029

Hey Vicmam, long time no talk! Just another one of Bob Harris's great designs! Happy Holidays to you & your family...Gene

1320Fastback

I was given a new Golden Bee a while ago. Not being in RC for very long I wanted to experience these old motors so I put it in my retired trainer.

This plane hung in my garage for 2 years until a few months ago. It is heavy having gone thru many repairs some of which added much weight because I didnt understand yet that weigh is EVERYTHING in flying.

I did move the pick up to the bottom of the tank and this Golden Bee has the secondary vent so inverted fight is no problem.

It usually turns heads everywhere I fly it and people always say they had them long ago and I always say... Get em back out!

WoodCutter

My Feedback: (8)

Hello everybody
Thanks for the encouraging words about the standard tank set ups. I still would like to know how well these engines draw fuel with the plastic backplate style mount (no tank) and the standard large engine practice fuel tanks.

I'm discovering that there are quite a few old posts on this forum and elsewhere that talk about the cox engines so I'm going to try and research this one a bit longer before deciding.
Thanks,

WoodCutter

combatpigg

My Feedback: (3)

The better the shape the engine is in [no crankcase pressure leaks and good compression], the better they will draw fuel.
High rpm [5x3 prop vs 6x3] increases fuel demand also...but if your tank is in a normal location the 6x3 prop allows the engine to rev high enough to develope good fuel draw.

The drawback to running a vented system with no muffler pressure is the switching back and forth from 2 cycle to 4 cycle running when you climb and level out...but that's the way it goes.


I've had great luck running them with a Hayes 2 oz tank and Sullivan small fuel line.

pmerritt

My Feedback: (118)

IT's getting to be GREAT catfishing season.  They will make a great weight for some 30# test line with some steel leader!

digital_trucker

You won't have any problems with aerobatics. If you fly inverted long enough, yeah...you might have an issue. Like Gene said, if you push it hard enough you might get a stutter or two. Cox Reedies don't need muffler pressure, and in fact pressure can cause problems with how the reed valve function. Just set the needle for optimum power, richen it back up a tad and go nuts....just like any other engine.

captaincrunch

You can screw it to the end of a baseball bat like we did when I was a kid. Fire it up, give it a toss and see how far it goes.

Tee Bee

Most of my .049 planes use a 1oz vented Sullivan tank. Installing a properly functioning flop tube is the most difficult part since the line is so short. A more flexible line than the one that comes with the tank is needed. I usually use Sullivan 1/2A fuel tubing for this. I've also used used flexible wire insulation stripped from the wire for this purpose. The clunk usually requires more weight than stock as well. Just get creative and it will work. The reedies are capable of drawing the fuel just fine. A stock Surestart with a 6x3 usually runs about 7 mins or so with that setup. A performance-modified reedie with a 5x3 lasts around 5 mins. My TDs run about 4-5 mins.

My engines usually run fairly consistent throughout the tank leaning slightly toward the end. Start off a tad rich and fly away. Make noise. Have fun.

skaliwag

My Feedback: (1)

What about a DNU?

flyinrog

My Feedback: (1)

look up at the sticky on the LST 1/2a trainer...all you need...Rog

WoodCutter

My Feedback: (8)

Thanks all, that was what I was looking for. Sounds like a fun project either with the built in or external tank.

WoodCutter

1320Fastback

Few pics of mine

2:45 seconds up and 1:40 down