What about a cox .049 engine endurance contest???

Mark Diedrichs Sun Jul 14, 2019 6:25 pm

Maybe a cox engine supplier would donate a.049 engine. Here's how it may go. The engine will be mounted on a bench test jig. Prop to be determined. Half gallon of 15% mix should be fair. Let's see how long it runs??? Whoever guessed the closest time wins !!!! What Y'all think, should we go for it??? Mark

ticomareado Sun Jul 14, 2019 7:59 pm

Oh, but you forgot global warming.

**RknRusty** Sun Jul 14, 2019 9:55 pm

If it's assembled with thread locker in the backplate screws, then it should run until the reed stops sealing or the head comes loose. Or the glow coil falls apart. Higher nitro, like 20% or 25% might be better for it. I think it should run cooler than the 15%. The engine should be well broken in at the start, enough so that the con rod can be reset, preventing that as a cause of failure. If we allow a non standard plug like a Merlin drop-in, a cold one will have a thicker, more stout glow coil.

Does the operator leave it running unattended while sleeping at night, Lol? I bet it'll easily outrun a half gallon of fuel.

I'd like to know.
Rusty

crankbndr Sun Jul 14, 2019 10:44 pm

Unless I made a gross error I figure 1/2 gal should run a Golden Bee 16 hours. Old Bugger

GUS THE I.A. Sun Jul 14, 2019 11:48 pm

Several years ago, the site hosted a type of endurance contest: to fly one engine, over the course of a year, and log the elapsed flight time, then report it at the end of the year. That was a fun event - R/C and control line categories were involved. At least I knew how many flights, and the duration of them for a year, I made.

KariFS Mon Jul 15, 2019 3:27 am

RknRusty wrote:
Does the operator leave it running unattended while sleeping at night, Lol?
Rusty

I would have to be pretty tired to be able to sleep next to a screaming .049 lol!

Oldenginerod Mon Jul 15, 2019 6:17 am

KariFS wrote:
RknRusty wrote:
Does the operator leave it running unattended while sleeping at night, Lol?
Rusty

I would have to be pretty tired to be able to sleep next to a screaming .049

I'd suggest to reduce the amount of fuel to keep the run time to 5-6 hours (without giving anything away). I have no idea how much that might be, but maybe the "runner" of the engine could do a pre-test to get a rough idea of the figures to keep it within a range, then publish the quantity of fuel and call for guesses.
The idea has merit, but I don't think anyone will expect someone to run it "around the clock". Then again, if someone has the time, space and lack of neighbours/family, even that's a possibility.
To keep to the theme, maybe use a Texaco??

**RknRusty** Mon Jul 15, 2019 2:26 pm

Rod, that Texaco might poke along for about a half a year or more... I'm just talking in jest, I actually have no wild guess how long a Cox .049 reedy will run non-stop, 24/7. And I know they shouldn't be left unattended, but if it's in a "certifiable" safe test cell, I'd let it run day and night, night and day.. Like I said in my first reply, if the screws don't loosen and the head doesn't blow out, the reed is the weak link.
Rusty

Mark Diedrichs Mon Jul 15, 2019 7:26 pm

Think it should be a out of the box, cox .049 engine. no break in or lock tight or piston rod reset. We are talking as is. No mods or tweaks . Put it in a engine jig and let her rip!!!!! All day, All night until she gives up the ghost!!! Think it would be a great contest/ learning experience. Wonderful & why not!!!! Can you smell what the CEF is cook'in. I hope it comes true, Mark

crankbndr Mon Jul 15, 2019 7:53 pm

I’d love to do it just to [bleep] off my neighbors but would take two. Prolly run for days Very Happy

Jason_WI Mon Jul 15, 2019 9:08 pm

Interesting read on endurance testing cox engines.

https://www.rcgroups.com/forums/showthread.php?1325147-Cox-oil-testing-findings

Ken Cook Mon Jul 15, 2019 9:17 pm

A similar test was discussed many years ago on another forum . Some of the members were former Cox employees who mentioned a very absurd amount of run time given to the engine. There was little wear on the engine when taken apart. I have run engines (Non Cox) for nearly 8 hours straight just to get rid of old fuel. I personally don't see any ill impact on doing the same to a Cox .049 assuming the proper fuel is offered.

I read Jason's post and I would like to offer my experiment which included a product Cox .049 engine. I was using 30% nitro 24% oil Morgan heli fuel full synthetic. I tightened the ball socket to almost no play prior to running. I put a entire gallon through this engine. I took the engine apart and there was no more noticeable play in the ball socket than what I started with. I personally didn't measure the parts and pieces but it concluded that the suspect of using full synthetic fuel would destroy a Cox engine for me. I use it in the cooler months due to using bladder on TD's. Castor based fuels congeal and the run goes lean after the bladder pressure starts to deplete. Synthetic fuels have a thinner viscosity therefore it doesn't impact the bladder like the castor fuels do.

balogh Tue Jul 16, 2019 12:53 am

On page 1 of this document Larry Renger ex COX executive refered to an endurance test COX had run on a stock engine and even after 400 hours run it could be restarted with an electric starter.

https://documentcloud.adobe.com/link/track?uri=urn%3Aaaid%3Ascds%3AUS%3Af4a8e1a1-ae17-4d1e-8c48-acf43ca4e3c3

If the above link does not open you will find the doc at the very bottom of Instruction Sheets to the left here..

My humble experience with COX engines is that unless abused - run lean or on too low castor ratio - they will deliver terrific long hours of dependable performace.

batjac Tue Jul 16, 2019 5:29 pm

Okay, I'll bite. My flying field does not have a requirement for mufflers, so I could set up a test stand (saw horse) at the field and mount an engine on Bernie’s universal test stand. I always play with my toys, so I can’t say as I have a new, bone stock engine to play with. So, I will buy a brand new engine from Bernie (Cox International Product Engine), put a starter spring on it, and take it to the field for an endurance run.

As has been stated, a gallon would take forever, so I propose running a quart. I’ll pony up the engine and accessories if someone(s) else is willing to pony up a quart of fuel. Nitro/oil content up to them. Anyone who wants to (excluding myself, of course) can put their guess as to how long it will run on an official endurance guess thread. I’ll run the engine continuously for the full quart, videoing the start, and hopefully the end. I’ll time the complete run, and whoever guesses closest to the actual run time wins. I’ll box up and ship the engine out to the winner after announcing.

What Say Ye?

The Long Haul Mark

Mark Diedrichs Tue Jul 16, 2019 5:44 pm

What??? batjac, I just hear crickets!!!!!,

batjac Tue Jul 16, 2019 5:45 pm

Sorry, I'm at work, and our auto-ergonomic keyboard software posted my reply before I was finished typing.

The Mark Interrupted

roddie Tue Jul 16, 2019 7:40 pm

A few years ago I mentioned the possibility of a CEF/Lindbergh event.. which would be more of a "duration" record for keeping a Cox-powered C/L model-airplane in the air.. without refueling. The model would have to R.O.G. and remain airborne to qualify for an official time-aloft. Models would be required to be at least a stand-off scale representation of Charles Lindbergh's Ryan M-2 based N-X-211 ship designed by Donald Hall.

Think about that for a few minutes.. Huh...

It would require doing some research, choosing an efficient airfoil, deciding on a "scale/size".. and designing an air-frame to be critically lightweight.. yet strong-enough to support the fuel-payload.

A prospective-pilot would need to be able to "fly" the model for a much-extended period of time, which is a major consideration.

Levent Suberk Tue Jul 16, 2019 7:50 pm

Here is the thread Roddie mentioned:

https://www.coxengineforum.com/t4827-yo-ron-please-bump-your-endurance-run-thread-to-the-top-again?highlight=endurance

Levent Suberk Tue Jul 16, 2019 7:54 pm

batjac wrote:Okay, I'll bite. My flying field does not have a requirement for mufflers, so I could set up a test stand (saw horse) at the field and mount an engine on Bernie’s universal test stand. I always play with my toys, so I can’t say as I have a new, bone stock engine to play with. So, I will buy a brand new engine from Bernie (Cox International Product Engine), put a starter spring on it, and take it to the field for an endurance run.

As has been stated, a gallon would take forever, so I propose running a quart. I’ll pony up the engine and accessories if someone(s) else is willing to pony up a quart of fuel. Nitro/oil content up to them. Anyone who wants to (excluding myself, of course) can put their guess as to how long it will run on an official endurance guess thread. I’ll run the engine continuously for the full quart, videoing the start, and hopefully the end. I’ll time the complete run, and whoever guesses closest to the actual run time wins. I’ll box up and ship the engine out to the winner after announcing.

What Say Ye?

The Long Haul Mark

Thanks for this. Nitro content is important for runtime, I think. Can you tell nitro percent? Very Happy

ticomareado Tue Jul 16, 2019 8:06 pm

Thanks Jason for the R/C Groups link. I printed that one for my paper archives. I wonder what exactly is tricresyl phosphate (TCP) and where can it be sourced in reasonable small quantities?

Mike1484 Tue Jul 16, 2019 8:35 pm

I believe TCP is a paint plasticizer . I use it with Duco Cement ( glue ) to keep it from shrinking on my indoor models . and warping them

Mike1484

Oldenginerod Wed Jul 17, 2019 5:14 am

batjac wrote:Okay, I'll bite.

What Say Ye?

The Long Haul Mark

I say yes. Sounds good. Keep it simple. When you mention endurance, different things come to mind. Mark Diedrichs original suggestion said nothing about the mechanical endurance of the engine or the ability of a Cox powered aircraft to stay aloft for an extended time. We're talking fuel consumption here. That's what Mark (Diedrichs) suggested and that's what Mark (Batjak) has agreed to run. All we need to do now is make a guess how long it will run and await the results. Of course, the fuel mix and prop need to be announced early so people can do a little experimenting of their own, but we don'e need an exact run time. It's just "closest to the pin".

So CEF friends, lets not meddle too much with rules etc. or the whole thing may become a chore. It would be great for a couple of members to contribute, as Batjak has suggested, with fuel. He has said that he will cover the cost of the engine, but I'm sure a contribution in that area would be appreciated as well, then there's shipping cost to the winner as well. All pretty simple and inexpensive if we choose to keep it that way.

Rod.

ticomareado Wed Jul 17, 2019 7:58 am

Mike-- Anybody who does indoor microfilm models is at the pinnacle of aeromodelling as far as I'm concerned.

Mike1484 Wed Jul 17, 2019 11:50 am

We don't do microfilm much anymore , most planes are plastic ( OS film or poly micro ) . Most of the indoor flyers are very dedicated to flying just indoor and they are very good at it . The Lindberg endurance thing sounds interesting . Maybe just limit the fuel capacity to the Bee stunt tank .

Mike1484

gkamysz Wed Jul 17, 2019 12:38 pm

ticomareado wrote:Thanks Jason for the R/C Groups link. I printed that one for my paper archives. I wonder what exactly is tricresyl phosphate (TCP) and where can it be sourced in reasonable small quantities?

TCP is a well known extreme pressure or antiwear additive for lubricants. It's not new. I would be surprised if commercial fuels and lubricants didn't already use it.

I'm in for the Lindberg Event! Spec class takes much of the airframe influence out of the equation and Bee tank keeps the flight time reasonable.

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