Brand new Cox .049 Engines at 1/2 price! (Full Version)

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Cox International -> Brand new Cox .049 Engines at 1/2 price! (7/5/2012 9:39 PM)

Because our engine lineup has grown too big, we are discontinuing 12 models. Of these engines, a total of over 80 are in stock (between 2 and 10 per engine) and we are offering them at 1/2 price in our clearance section here:

http://coxengines.ca/clearance/?&sort=orderby&sort_direction=0&objects_per_page=51

on a first come, first serve basis. Also, 10 of these models will have one each listed on eBay as auctions staring at 98 cents here:

http://stores.ebay.ca/XENALOOK/CLEARANCE-/_i.html?_fsub=2420964015&_sid=476927475&_trksid=p4634.c0.m322

This is your chance to own a Cox engine at half the going market rate
 
Bernie

www.coxinternational.ca



stackerjack -> RE: Brand new Cox .049 Engines at 1/2 price! (10/8/2012 4:55 PM)

Hi,
Could anyone please tell me where to find the power rating of various Cox 049 engines please. All the data I've found so far says 15000 to 17000rpm using 25% nitro.
This is more or less the same for all different models, with 1 or 2 minor exceptions.
Thank you
Jack



MJD -> RE: Brand new Cox .049 Engines at 1/2 price! (10/8/2012 5:19 PM)

Rpm isn't power, those numbers are just typical operating range, and indeed a good range to run most of them except in specific applications. The most info in one spot can be found at Dr. Hepperle's site http://www.mh-aerotools.de/airfoils/cox_frameset.htm



TampaRC -> RE: Brand new Cox .049 Engines at 1/2 price! (10/8/2012 5:49 PM)

If I have two identical Cox engines,  and one turns 15000 rpm and the other turns the same prop at 22,000 rpm,  wouldn't you say the one that spins it at 22,000 has more power?



WINANS -> RE: Brand new Cox .049 Engines at 1/2 price! (10/8/2012 9:23 PM)

It fully depends on what load (prop) they are turning.

Added later: I wasn't observant enough to read that he include 'same' prop in his question. Too zippy for my own good.



BMatthews -> RE: Brand new Cox .049 Engines at 1/2 price! (10/8/2012 9:36 PM)


quote:

ORIGINAL: TampaRC

If I have two identical Cox engines,  and one turns 15000 rpm and the other turns the same prop at 22,000 rpm,  wouldn't you say the one that spins it at 22,000 has more power?





Of course it does. But it doesn't answer stackerjack's question.

Stackerjack, I doubt if hp figures would do much good for you or us. Instead it's all about what sort of model and how fast it can fly. That is a far better yardstick of power than some hp figure.

Cox engines are generally at their best when fed higher nitro fuels. That means 15 to 30%. If you can't get such fuel you're better to stick to other options. And as I understand these things higher nitro glow fuels in the UK are a rather princely sum which you may not want to pay. Mind you a Cox engine uses it frugally so perhaps it's worth the cost? Generally these engines are at their best with a 5x3 to 6x3 prop.

The sort of model which flies best with a basic Cox Reed engine is going to be about 36 inches span, weigh in at 22 or less oz of weight and will not be intended for 3D maneuvering. Basically we're talking about a good performer that isn't overly fast, won't climb vertically but will entertain with lots of maneuvers that can be done by whatever style of model and will deal with moderate winds with grace and land at less than sonic speeds.

On the other hand that same engine will get a powered glider of up to 6 foot span and weighing in the mid to high 20's oz range up to thermal country pretty well with a 2 minute engine run. It'll be more of a strong uphill glide than a true "climb" but when the noise stops you'll be up high enough that you'll get some long flights as long as you don't toss it around and force it down.

That help?



MJD -> RE: Brand new Cox .049 Engines at 1/2 price! (10/8/2012 9:46 PM)


quote:

ORIGINAL: TampaRC

If I have two identical Cox engines,  and one turns 15000 rpm and the other turns the same prop at 22,000 rpm,  wouldn't you say the one that spins it at 22,000 has more power?




Yes, I understand that turning the same prop faster requires more power, thank you for asking [:)]. But his post says nothing about prop size, he is only quoting rpm ranges with no reference to load. There is little to nothing published anywhere about Cox engine power that I have ever seen, with the exception of Dr. Hepperle's website.






stackerjack -> RE: Brand new Cox .049 Engines at 1/2 price! (10/9/2012 7:52 AM)

Thanks for your help, and the description of model size suitable for a Cox Engine. I'm planning to use it in a 1.4M span Hawk 1400 (Not a Hobby Hawk, but similar).
It's electric at the moment, but I just love engines too much.
All I need to know now, is WHICH Cox 049 is best.
Thanks again,
Jack



stackerjack -> RE: Brand new Cox .049 Engines at 1/2 price! (10/9/2012 7:56 AM)

An engine that will turn the same prop. faster does indeed have more power. If you change prop. sizes, then torque comes into the equation.
For those people not exactly sure of the difference between torque and horse power, suppose you have a car with a 100hp engine. If you use a low gear, you will get the best torque available, but the engine will never produce more than 100hp.



exocet-RCU -> RE: Brand new Cox .049 Engines at 1/2 price! (10/9/2012 8:09 AM)

With a 1.4 m wingspan, I think any of the ones listed should do the trick. For ease of use and not having to plumb a tank into the glider, you might consider one of the ones with a tank on it. You won't get as long a run time but, as Bruce said, you will get enough to get up high enough to catch a thermal or have a pretty decent glide time down.

Tim



MJD -> RE: Brand new Cox .049 Engines at 1/2 price! (10/9/2012 3:45 PM)


quote:

ORIGINAL: stackerjack

An engine that will turn the same prop. faster does indeed have more power. If you change prop. sizes, then torque comes into the equation.
For those people not exactly sure of the difference between torque and horse power, suppose you have a car with a 100hp engine. If you use a low gear, you will get the best torque available, but the engine will never produce more than 100hp.


Thee engine produces the same amount of torque at a certain rpm and throttle setting regardless of what gear it is in. You're talking about torque at the wheel which is amplified at the expense of rpm by the transmission.

Back to Cox engines, I see where the rpm numbers you quoted come from. The reason these all look the same is essentially because they are the same top end on various tank arrangements plus cosmetic touches like anodizing.

I think you would be fine with the Skymaster - http://coxengines.ca/cox-.049-engine-skymaster.html

It has the larger tank you'll want for run time to get altitude.




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