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i think i have the crazy... please talk me in or out of it

#1
So. i really want to get into nitro rc, but i do not have the money for your traditional first nitro plane... then i found this...

http://coxengines.ca/cox-.049-rc-cruiser-engine.html


and now i want to put it in a swappable!!

Can i get any advice on yes or no? i know i will have to beef up the structure of the power pod, but my main questions are these:

will it give me adequate power?
(i love scale flying so not being able to hang on the prop is not a deal breaker)
(i am considering doing this in an ft racer with fixed gear in a 20's era pylon racer style)

will i end up being too nose heavy even with a receiver pack toward the rear?

if i lacquer the foam board before i build, will the foam board able to survive the fuel and exhaust from the engine?

Is this an appropriate size engine, or can i go bigger?



so there it is, my quest to turn an airplane never meant to fly with nitro, into a nitro bird..



knowledge heavily requested and greatly appreciated.
 
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xuzme720

Dedicated foam bender
Mentor
#2
I have used an .049 on a 2M glider so you should have no issue with power, and the motor is very light so balance shouldn't be a problem. Remember, you will only need a smaller Rx battery and not a large flight battery. I have never tried fuel on minwaxed foam so that might be a deal breaker, but you could test it on some scrap foam first...
 
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#3
I was considering doing two power packs. Tracing out the power pod and making one with the beef package. Then experimenting with balsa reinforcement at the front end or maybe a plastic wrap to create a barrier in the pod itself. Would a .049 be able to swing an 8x6 or a 10x8
 

xuzme720

Dedicated foam bender
Mentor
#4
I think they are better suited to a 6x3 or 6x4...
I can't remember that I ran anything bigger than that...
 
#5
hmm.. supposedly according to the cox website. the biggest prop the recommend is an 8x4.. what exactly will the characteristics of that prop be, and what sort of power will i need to carry for flight.

i was also wondering about the break-in of the engine.
 

xuzme720

Dedicated foam bender
Mentor
#6
The Cox I had was closer to this so you might be able to get away with a larger prop since your version is carbed...
Break-in is a few tanks run really rich and let cool in between tanks. Slowly start to lean it out after those first few tanks. Should be broken in after maybe 6 tanks IIRC.


I went out and got mine to make sure. What I have is this one and I have a 6x4 prop on it... I guess that doesn't help you much though.
 
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pgerts

Old age member
Mentor
#7
8*4 is way to big unless you go for the diesel version. The cox is made for hight rpms and not torque like Electric motors. The new cox Engines will be sold by HobbyKing! Anyway - unless you want the sound - Electric is better/cleaner.
 
#8
8*4 is way to big unless you go for the diesel version. The cox is made for hight rpms and not torque like Electric motors. The new cox Engines will be sold by HobbyKing! Anyway - unless you want the sound - Electric is better/cleaner.
oh i get that electric is quieter and cleaner. this is more of a challenge thing. can i make a nitro conversion for a swappable. ill be duplicating the power pod so that i can make a pod for each power-plant. this is completely an experiment.


eta: i also like fiddling with engines and crap. so loud and dirty is fine by me. larger nitro just seems to expensive for me at the moment.
 
#9
xuz, what kind of power were you getting with yours. am i going to be dealing with stupid amounts of climb, or will this thing fly a bit more scale (underpowered for sport but fine for scale)
 
#10
You need a little howto from Bruce aka xjet

By the way, yes you can get the 049s to turn an 8x4 but they do so at a low rpm, low power output. This was typically done for an event called 1/2A Texaco where models were basically just RC assisted FF planes that were scaled down versions of old timer planes. They took little power to stay aloft and had fuel limits SO folks would get long runs out of the overpropped cox engines and then glide forever. More conventional propage would be 5 or 6 x3 or 4. APC made a high output scimitar prop that was a 5.7x3 inch prop that screamed real nice on a TeeDee/Black Widow .049/.051. Would use them in Control Line ships all the time.

They are fun to play with. Be aware that 1/2A is more finiky then larger displacements and the cox engines like/need all castor for their ball seat on the pushrod. That will need reset eventually and THAT is a technique I never really got good at. But I had a bunch of fun with engines before they needed reset. Although I had several of these later production engines that not only needed reset out of the bag, I even ruined several of them during their first runs. Cox international took over the production after that so their quality is probably much much higher then the ones I bought from Cox/Estes.
 
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xuzme720

Dedicated foam bender
Mentor
#11
Well, I was using the one I have, to pull up a 2 meter sailplane, with the .049 on a power pod strapped to the wing. I had decent climb rate but it definitely wasn't anywhere near vertical. I'm sorry but I never measured the actual thrust I was getting.

I think it would be ok for any of the swappables and should not be very underpowered if underpowered at all. Since you are looking at one with a throttle, you can always throttle back if it gets too hairy.
 

Yogenh1

Junior Member
#14
I started with the Cox .049 back in 1975 and at that time they had a great engine. I started with the Cox 2 channel radio that that had out then. It sold for $150.00 back then. That was my start into RC. I think that a 6-4 prop would give just what you want. That is what I used all the time
 
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#15
fuel proffer!

from every thing I've read on the internet Minwax polyurathane liquid in the can is fuel proof. I haven't tried it yet with glow fuel but I do use it when I want to paint a dollar tree foam board airplane. Just pour it on and wipe off all the excess. It does make the paper very tough without adding a lot of weight. I built a cub (60 in ws) using Minwax and a spray paint finish. I posted it under fixed wing electric. Yes it is 90% foamboard & yes it flies great. I've got one of the new cox rc engines, Might have to try what you are doing myself. good luck with your project.
 

Tritium

Amateur Extra Class K5TWM
#16
Cox .049 on a control line plane (really just a balsa plank) was my first taste of powered flight other than 15 cent balsa rubber band powered grocery store models.

Coroplast is definitely the way to go and can be had after an election (roadside election signs) for nothing usually. Even highway departments use it for road signs now in many locations.

Thurmond
 
#17
I fly nitro planes a lot and have a fair amount of time and knowledge into them, and think that it would work if you monocoted the airframe first. The exhaust is the major problem in nitro because it gets into every little place that you can think of when not built properly and ruin electronics and what not.
 

PeterGregory

CrossThread Industries
#19
There are a couple of threads online that come to a conclusion (as I have) that electric and glow engines are.... they have offsetting positives and detractions so they are about the same, all things considered.

I have both, and I give FT credit for the cheap performance electric foamies got me back in the hobby this year. I revived and expanded my fuel engines alongside the electrics. When I first started building a hangar of FT $TFB planes, I had more fun than anyone ought to have. But gradually I heard the Call of Glow Engines. Foam and Balsa shall live side by side. You can fly electrics in far more places than glow and not draw too much attention. I now have electric, glow, diesel, and gas - up to a Genoah 38.

BTW, You can get even cheaper Cox .049's on eBay. New or used. Here's a new SureStart under $25:
Cox SureStart.jpg

Note! The current formulation of Cox Super Fuel being sold IS NOT CORRECT for Cox engines and through pressure from the online community the company (Hobbico) is reformulating. I got stuck with $50 of that fuel which is what would be on the shelves at this time. BUY SIG Fuel(!) over the internet which is what the guys in-the-know do. I ended up having to buy the Sig 25% Competition Fuel, another $50 for a gallon.
SigChamp25Fuel.jpg

Cheers,
Poughkeepsie Pete
 
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