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Can anyone recommend a F/F design for a Cox Black Widow?

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Can anyone recommend a F/F design for a Cox Black Widow?

Old 09-04-2005, 01:07 PM
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serendpt
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Default Can anyone recommend a F/F design for a Cox Black Widow?

I recently acquired a Cox Black Widow that I'd like to put into a free flight model. I'm looking for something relatively easy to build and won't fly too fast. Perhaps even an old timer design would be suitable. Any recommendations?
Old 09-04-2005, 08:05 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

This is a tough question. A Black Widow will fly a free flight model from as little as 30 inch span and on up to a lightly built 2 meter glider without the radio in it. Big is good as it will deal with the power better. But smaller models are easier to keep within a more confined field. Also they are easier to transport. A smaller all sheet model will also be less likely to hook a thermal. In any event I recomend a Dethermalizer of some form just to be sure it doesn't fly away. Also the DT can be used to control the flight time and avoid long chases.

The trick for flying smaller models with this engine is to turn the prop around backwards so the flatter side is facing forward.

But if you don't mind a slightly larger model then a simple cabin model of about 46 to 48 inch wingspan is good. I would also recomend that to control the power and flying speed that you use an 8x4 prop on the engine with 2 or 3 extra head gaskets and only 5% nitro fuel. This should fit in with your plans to keep it cheap as high nitro fuel is often costly in some countries.

Let us know a bit more about what sort of model you want to build.
Old 09-05-2005, 04:55 AM
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serendpt
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

I was aware of the prop trick but didn't think about the extra head gaskets. What material can these be made from, should I not be able to source any locally? I haven't opened this engine up yet so I'm not sure if there is a head gasket there.

I'm looking for a design that I could fly in a 1 acre field. I'm not keen on the small, fast designs, I'd much prefer something larger that would fly sedately. Something along the lines of Vic Smeed's Tomboy looks about right, but I'm not familiar with the flying characteristics of this plane. Browsing the online plans catalogues can be an excercise in frustration as they're not always categorized well.
Old 09-05-2005, 05:29 AM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

Hi

Even a hand launched glider would be difficult to confine within 1 acre and no wind. Gas free flight is a lot of fun but requires around 10 or more acres. Obviously this is an opinion. I cut my teeth on 20 acres of farm land and lost many a model in the process.

Gene
Old 09-05-2005, 01:21 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

I have to agree with g-rock. One acre is far too small for any form of gas free flight if there is ANY wind at all. Even if there isn't any wind a model will easily fly outside the bounds of an acre or two on a regular basis at that size of engine and plane. The only design that would fly even half way reliably within a smaller area is the all sheet balsa Dakota biplane. But a Black Widow would be far too much power for that design even with the prop on backwards. You've have to put a strip metal exhaust baffle around the cylinder to throttle it down a bit. But if you did that and drill out the tank bell for a small external fuel supply then it would work. The Dakota biplane is about a 25 inch span and generally flies up to about 150 feet of climb in about 40 seconds of power and then glides back to earth in about a further 20 to 30 seconds. Such a "brick like" performance means that it is one of the very few models that does not need a dethermalizer. But even with the Dakota or a model sort of like it you really need an area about the size of at least 2 soccer pitches side by side. And even then you would only be good to fly the model in winds up to maybe 4 to 5 mph or it would drift off the field before it came down. I've attached a picture with some Dakotas below....

The Tomboy is a lovely model and probably one of the more common sport models just because it is such a good flier. But it was designed for a very low power diesel engine and with a Black Widow it would be a real screamer. But as above, if you were to make up a little sheet metal strap that goes around the exhaust ports to act as a throttle then you could use the BW to fly such a model.

RC would be OK. But if an RC unit is not within your budget what about control line flying?

There is one gasket in the engine. If you unscrew the glow head there will be a thin copper metal ring in there. That's the gasket. The normal way to reduce the compression is to add spare gaskets but if you only got the engine and don't have any extra glow heads then you won't have any spare gaskets. In that case you could make your own from thin and SOFT aluminium. Something like 0.2 to 0.3 mm would probably do the trick. Of course to make such a small part from soft aluminium will require some great care or special tools.
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Old 09-05-2005, 02:39 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

Hey brian know where I can pick up a copy of plans for the dakota you got there? Would love to build one of those!
Later RobinB!!
Old 09-05-2005, 03:23 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

I saw a program on TV Last night about control line flying..I was impressed at the arobatics the guy was doing .Maybe consider that, YOU would stay on your 1 acre,and be able to, build a plane your engine would handle..Lots of free plans around too,just a thought
Old 09-05-2005, 08:22 PM
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serendpt
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

As you can see, I have precious little experience with free flight It's been a good twenty years or more since I flew rubber models. Back then, every field was a candidate, and if it turned out to be a bad idea it didn't matter, I was young enough to climb over fences and swim through murky rivers to retrieve my plane. Funny how you age, you'd think you'd grow bolder with experience, but now would think more than twice about entering a field of bulls to retrieve a model plane!

I was initially hoping to build something that would make use of the Black Widow without breaking the bank, and that I could gain a little powered free flight experience with. I love the Tomboy and similar designs, but a diesel engine would be a bit out of budget right now (exchange rate and all.) I don't think the Black Widow is a suitable candidate for diesel conversion, either.

As for control line, that was the other consideration. As D Bronk said, plenty of suitable free plans and I could still keep it within the confines of my field. Something to think about...

Thanks for the ideas, everyone, Ill let you know what I decide.
Old 09-05-2005, 08:44 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

Here's a site of free plans for cl, many for 1/2a..[link=http://uk.geocities.com/[email protected]/_cat001.html#row3]tony elmore's plan site[/link]
Old 09-05-2005, 10:34 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

If your thinking about a C/L model , try the second version of the Ferdinand. I built 1 as a teenager and its a nice flyer on a cox 049, I taught a few M8's to fly control line with it.
Stewart
Old 09-06-2005, 12:08 AM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

I've flown several Dakotas with Baby Bees (built my first one in '52 or '53). The one I fly now has an OK Cub .049. If you're looking for a high quality laser cut kit, go here- http://www.bmjrmodels.com/. Check out their 'Twin Lizzie' for Pee Wee power. Jim
Old 09-06-2005, 02:16 AM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

No need for that diesel. The black widow will work fine but you just need to choke it down a bit to contain the power so it's in tune with the gentle style of flying it sounds like you're after.

This is a sketch of the exhaust strap I was describing earlier. The gap between the two ears should be about the same width as one of the exhaust ports. The bolt and nut can be something small like 2-56 or 2 mm. It's just used to pinch the restrictor in place.
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Old 09-06-2005, 06:29 AM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

Hi,

You need an old plane called the Sioux. Was kitted by Veco and plans are available thru RCM for the "R/C Sioux" Great plane, and fits your bill. Have fun, I'm building another one....

Dan
Old 09-06-2005, 08:50 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

I have an article from an old Aeromodeller about tethered freeflight (an oxymoron ). the basic idea is that you build a slow flying airplane and attach a fairly long strong thread to one wing trailing edge about 2/3 the way out to the tip. You let the airplane take off with the thread slack. Drag of the thread will turn it to the thread side if you stand still or back up. If you walk along the airplane will fly straight. If you walk (run?) faster the airplane will turn the other way. I haven't tried it, but it sounds interesting for small field flying.
Old 09-06-2005, 11:31 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

I have a Black Widow on an Aerodyne 36" Mercury. I believe it was originally made by Scientific. I modified it with basswood spars and two dowels for the front of the wing mount instead of the one center dowel. I have a Hitec AM two channel radio in it with HS-50 servos. It will go so high that it nearly disappears. The radio is a must here in east Tennessee. I also have a Golden Bee, and a single bypass Babe Bee with a Black Widow tank. I call it "Black Bee".
Old 09-07-2005, 07:03 AM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?


ORIGINAL: BMatthews

This is a sketch...
Yer showin' off now Bruce!
Old 09-07-2005, 02:53 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?


ORIGINAL: DICKEYBIRD


ORIGINAL: BMatthews

This is a sketch...
Yer showin' off now Bruce!

What can I say... CAD is my friend...
Old 09-07-2005, 08:10 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?

Between you and bsindel, maybe I'll learn enough to put some Isometric views into my stuff.
Old 09-07-2005, 10:41 PM
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Default RE: Can anyone recommend a F/F design for a Cox Black Widow?


ORIGINAL: BMatthews

But even with the Dakota or a model sort of like it you really need an area about the size of at least 2 soccer pitches side by side. And even then you would only be good to fly the model in winds up to maybe 4 to 5 mph or it would drift off the field before it came down. I've attached a picture with some Dakotas below....

Bill, I must confess That were it not for Harry Potter I would have had no clue to what you were referring to when you said "pitches". Evidently Quidich and soccer are played on a similarly named piece of ground. In my younger days (not that long ago, mind you) I played sports such as football and baseball on a "field".

Aside from the name of the place from which it is flown, the Dakota is a neat bird indeed. I have one (presently unflown and thus intact) with a Cub .049 B in the nose. I have l likely field, currently planned in soybeans about a half mile from my shanty. Given the combination of a calm day and getting the Cub to start I will give it a try.

jess

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