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1/2 A Roland CII

Old 06-27-2011, 06:06 AM
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ZoomZoom-RCU
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Default 1/2 A Roland CII

Well, she's ready to maiden, (almost), engine tweaking in the works. She sports an APC .09, which is almost to the point I'm comfortable trusting her to leave terra firma.


ZZ.
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Old 06-27-2011, 10:09 AM
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Default RE: 1/2 A Roland CII

ZZ -

Make sure you have sufficient cooling. I didn't see any exit holes in the cowl - the rule of thumb is to have 2 to 2.5 times the exit area as input area to allow for air expansion. Otherwise, you'll get air compression in the cowl and have little, if any, cooling air.

Plane looks nice - I like the color scheme, just like you're ready for the dawn patrol!!

andrew

Old 06-28-2011, 05:45 AM
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Default RE: 1/2 A Roland CII

Thanks Andrew,

Yeah, cooling is one of my main concerns. The engine head does stick up pretty well into the airstream, more than it seems in the pics, but I am also gonna run the engine a little rich to try and handle that issue as well.

ZZ.
Old 06-28-2011, 06:53 AM
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Default RE: 1/2 A Roland CII

yes that engine will get very hot and will quit. you need to cut some cooling holes on either side of the cowl behind the engine!!!!
Old 06-28-2011, 06:58 AM
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Default RE: 1/2 A Roland CII

How are you venting the exhaust?
Old 06-28-2011, 08:41 AM
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Default RE: 1/2 A Roland CII

This APC has a round drum shaped rear muffler, which allows you to turn the exhaust port 360 degrees, so I simply am venting it straight down and out of the bottom of the engine compartment with a hose. Seems to be working well. i'd love to try this little engine in an ME109 design, again that is, if you could get enough air flow to it to keep it cool.

ZZ.
Old 06-28-2011, 07:01 PM
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Default RE: 1/2 A Roland CII

you will still need more cooling holes than that tiny thing you have.

IT WILL OVER HEAT LOSE POWER AND DIE!
Old 06-29-2011, 06:13 AM
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Default RE: 1/2 A Roland CII

Did some tests last night, she seems good to go. Engine is being run a tad rich, but after about 3 or 4 minutes of steady running you can still stand to put your finger on the engine head for 2 to 3 seconds before having to take it off, so that seems good. One aspect you guys probably cant see is that there is a large gap behind the engine, (and between it and the rear mounted muffler) that allows airflow to pass around the motor-head and out the backside, up and behind it. Its hidden in the pics behind the "ocarina" goofy looking fake muffler mounted on top of the engine. She also seems to transition well between low and high idle, with no stalls or cut-outs, so, as things stand, we'll probably give her a go sometime after the 4th weekend. I'llpost some vids when they are available.

ZZ.
Old 06-30-2011, 06:41 AM
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Default RE: 1/2 A Roland CII

She looks very realistic..! The first photo really brings that plane to life. Nice job ZZ........[8D]
Old 06-30-2011, 06:57 AM
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Default RE: 1/2 A Roland CII

Hey, thanks CP!!

ZZ.

This ones for you

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Old 06-30-2011, 11:56 PM
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Default RE: 1/2 A Roland CII

NOW I think I know why that photo looked so realistic.....

....hey, if this model over heats and the engine dies, doesn't that earn more points for being "scale"?

I goofed around last year with a hand carved 9x2 prop on a .074 and it gave a semi-scale plane a low pitched semi scale sound, but probably not good for the longevity of the rod or crankpin.
Old 07-01-2011, 04:30 PM
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Default RE: 1/2 A Roland CII

Lol.

ZZ.
Old 07-01-2011, 05:23 PM
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Default RE: 1/2 A Roland CII

ZZ,

What prop is that you have there?

Thanks,
KP
Old 07-01-2011, 05:42 PM
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Default RE: 1/2 A Roland CII

Cp if the engine over heats and dies then he crashes the plane does that count for more scale points?
Andrew and I didn't see much for cooling air and wanted to help the guy out. We couldn't see any or much exit airflow on the model.

The model is done as a very scale plane. Great job
Old 07-01-2011, 07:36 PM
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Default RE: 1/2 A Roland CII


ORIGINAL: airraptor

Cp if the engine over heats and dies then he crashes the plane does that count for more scale points?
I don't know, it's been over 10 years since I landed a plane with the engine still running.
They either run out of fuel or they blow up.
Old 07-02-2011, 07:48 AM
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Default RE: 1/2 A Roland CII

What prop is that you have there?

I believe its a 7x3 or 7x4 . Seems to be running at a nice steady rate, with a LOT of airflow over the wings. My estimate is that she'll probably lift off and fly on 1/3 throttle.

I very much appreciate everyones' help and suggestions, please don't think that just cause I'm not making suggested mods, that I'm ignoring you. She does seem however to be performing in a similar fashion to other successful machines I have built and flown. But fear not, if she fails to meet my expecations, your suggestions will most certainly be utilized.

I don't know, it's been over 10 years since I landed a plane with the engine still running.
They either run out of fuel or they blow up.


Yikes! You do have dead stick experience CP!!!! In that vein, I did have an experimental suffer from a wing strut connector failure, fold one wing back over the other, and spiral in. It was spectacular. Yeah, I lost the plane, but it was one of the few I've ever lost that I was grinning as she spiralled, all the way down, and for some time after to boot. She was, "experimental" after all. I learned to "fix the weakest link" after that occasion as well. Whole plane lost cause of a badly designed linkage that relied more on glue than mechanical attachment. Ah well.

ZZ.







Old 07-02-2011, 09:13 AM
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Default RE: 1/2 A Roland CII


ORIGINAL: combatpigg

I don't know, it's been over 10 years since I landed a plane with the engine still running.
Until the NORVELs and some recent throttle designs from COX International for COX engines, it was pretty much fly until you ran out of fuel. Probably 90% of my landings were deadstick.

Old 07-02-2011, 11:28 AM
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Default RE: 1/2 A Roland CII

Until the NORVELs and some recent throttle designs from COX International for COX engines, it was pretty much fly until you ran out of fuel. Probably 90% of my landings were deadstick.

Good point, and it was always "fun" with the designs that had not the best glide characteristics. Some you'd have to swoop in as if you were a crow landing, and flare right at ground level to touch down and keep from stalling out (at least someof mine..lol). I'm working on a fixed fuselage coupled to a rogallo wing design right now that I tested out in .049 scale first. Flies beautifully, but when that surestart runs dry, its so stable it doesn't like turning without engine assistance. I've found nose diving, then a sharp pull up and a stall turn to the right (towards the weighted wingtip) can get her back home.....if of course you have enough altitude! Always fun figuring things out.

ZZ.

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