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what's a good slick airframe for a pair of OS55ax's

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what's a good slick airframe for a pair of OS55ax's

Old 09-22-2014, 02:47 AM
  #51  
rcjunky67
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Originally Posted by stevegauth30
You talking about the kougar?
Well, yeah. mostly cause I have one sitting on the shelf . I don't really think I'm missing out if it get's bashed into something else. Like I said, it's gonna be a tester to see what I can come up with.

I've got 2 brand new 55ax's and a kougar kit that I ain't doing anything with. Way I got it figured, just need to figure out how to build nacelles into a foam core , sheeted wing... s'matter? coffee not kickin in yet? haha
Old 09-22-2014, 02:50 AM
  #52  
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Originally Posted by stevegauth30
No, still sitting on the shelf, covered in dirt. I'll get around to it. I've seen plenty of ducted fan jets running two stroke glows. It can be done. Just a thought. Hey, if you bash the kougar into a twin, you can call it a " TWOgar."
heck yeah, 'Twogar' , that's funny, your getting ahead of me on your posting !
Old 09-22-2014, 02:52 AM
  #53  
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Well, heck, Watcha waiting for? Tear that box open and let's get on with it. I don't have any experience with foam cores, but I've seen build threads of people who have built them. I know you can glue wood into the foam as to make hard points to mount to. Just think it out good and you'll come up with something. Especially with the help of people in these threads. Anything is possible.
Old 09-22-2014, 02:56 AM
  #54  
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I'd thought that the 55's were more of a torque motor than speed. I know I've seen the rpm range listed as, 2000 to 17k. But I've never seen one spin over the mid 14's and that was with a 9x7 prop on 15% nitro. how fast would a fan need to spin and how big would it need to be in diameter and how many blades at what pitch would be the equivelant for a say 12x6 prop?
Old 09-22-2014, 02:58 AM
  #55  
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Now I'm lost. I have no experience what so ever with ducted fans, only know I've seen em.
Old 09-22-2014, 03:00 AM
  #56  
rcjunky67
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Originally Posted by stevegauth30
Well, heck, Watcha waiting for? Tear that box open and let's get on with it. I don't have any experience with foam cores, but I've seen build threads of people who have built them. I know you can glue wood into the foam as to make hard points to mount to. Just think it out good and you'll come up with something. Especially with the help of people in these threads. Anything is possible.
thats all very true my friend. we'll see what happens . have a good day. I gotta go to work.
Old 09-22-2014, 03:03 AM
  #57  
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You too.
Old 09-22-2014, 04:37 AM
  #58  
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I wouldn't put twin 55's on a Kougar. It's way too much engine and as the gentleman said - it won't fly all that great with the extra weight. Twin .30's would be the most I'd put on a Kougar.

It can be bashed into a lot of things but I honestly think the two 55's will pretty much ruin the kit and you probably won't like it.

You just have way too many options. You have to decide what kind of plane you want - sport, scale, fast, not so fast, etc. I understand it being a hard decision. Too many choices is always harder than having one thing in front of you that doesn't give you many options.
Old 09-22-2014, 07:14 AM
  #59  
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Pat used to provide a laser-cut short kit version of the Duelist ([email protected]) for a reasonable price.
The Duelist is a great looking plane, and I have seen it with retracts. Not sure how fast you can push it though...
Old 09-22-2014, 07:28 AM
  #60  
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Mine has retracts and I fly it 'balls out' with no issues.
Old 09-22-2014, 07:51 AM
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I've designed and built a few sport twins in the past. The way to do nacelles on a foam wing is to build a plywood box big enough to hold the tank and servo. Put the firewall on the front of the box and make it long enough to go from the calculated firewall position to any spar that you have in the wing. Then just cut out the foam and glue the box in place.

The problem you will have with the Kougar is weight. You will be adding the extra engine, prop, spinner, tank, fuel, servo, two nacelles and two cowls. That would be adding at least three pounds to a 40 size airplane that is overweight to start with. Then if you add retracts......

You would need to make the wing larger to carry the extra weight. Then you need to make the tail larger to maintain tracking.....

But, hey.... As you said, you can try whatever you want. It's only an experiment.
Old 09-22-2014, 08:36 AM
  #62  
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rcjuinky 55AX and pitts mufflers will not be fast............
Old 09-22-2014, 09:10 AM
  #63  
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Originally Posted by jrf
I've designed and built a few sport twins in the past. The way to do nacelles on a foam wing is to build a plywood box big enough to hold the tank and servo. Put the firewall on the front of the box and make it long enough to go from the calculated firewall position to any spar that you have in the wing. Then just cut out the foam and glue the box in place.

The problem you will have with the Kougar is weight. You will be adding the extra engine, prop, spinner, tank, fuel, servo, two nacelles and two cowls. That would be adding at least three pounds to a 40 size airplane that is overweight to start with. Then if you add retracts......

You would need to make the wing larger to carry the extra weight. Then you need to make the tail larger to maintain tracking.....

But, hey.... As you said, you can try whatever you want. It's only an experiment.
yup, see in the land of "I don't know" there are a lot of variables. that's exactly why this forum is so great to have available. I was thinking the same thing about making the wing bigger as well as the tail feather's. I guess I'm probably thinking more along the lines of using the kougar kit as a baseline for measurements to expand from.not so much making the actual kit itself into a twin. thanks
Old 09-22-2014, 09:14 AM
  #64  
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Originally Posted by airraptor
rcjuinky 55AX and pitts mufflers will not be fast............
I was thinking more along the lines of using a macs tuned pipe on each. I've not ran any of my own 55's for speed, but one of our club members has one with a macs pipe running 30% nitro with castor and a 9x8 prop,still don't know whrere he got that from, and that thing will turn 16k all day long . so I do know they can be extremely fast if set up for it. it's not something I would do though
Old 09-22-2014, 09:25 AM
  #65  
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I wouldnt run a macs muffler either. 16,000 isn't very strong either and not where a stock 55 likes to be. Bone stock 55 AX does well with a 11x7 and a Red Jett muffler from Jett Engineering. If you run the Evolution "Blue" Jett muffler you can run a 11x8-11x9 prop.
Old 09-22-2014, 09:28 AM
  #66  
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You may be the first to run tuned pipes on twin nacelles. They would tend to stick out past the trailing edge a bit.

(Now someone will come up with a photo showing that it has been done, I'm sure.)

BTW, the King Cobra is a Sig kit of a larger size Kougar. You would still be adding 3+ pounds to it, but at least the basic airframe would start out with more capacity to carry it.

Jim

Last edited by jrf; 09-22-2014 at 09:39 AM.
Old 09-22-2014, 09:43 AM
  #67  
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I run Jett tuned mufflers on mine. Definitely add a significant amount of power. (Maybe not as much as a tuned pipe.)
Old 09-22-2014, 11:05 AM
  #68  
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How about this Baron?

http://www.scaleflying.com/Beechcraf...une-_p_27.html
Old 09-22-2014, 11:15 AM
  #69  
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That is a pretty Airplane!!!
Originally Posted by flapwad
Old 09-22-2014, 01:52 PM
  #70  
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The Duelist is was kitted by Pica
Old 09-22-2014, 02:28 PM
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Originally Posted by jrf
You may be the first to run tuned pipes on twin nacelles. They would tend to stick out past the trailing edge a bit.

(Now someone will come up with a photo showing that it has been done, I'm sure.)

BTW, the King Cobra is a Sig kit of a larger size Kougar. You would still be adding 3+ pounds to it, but at least the basic airframe would start out with more capacity to carry it.

Jim
It never fails!!!
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Old 09-22-2014, 02:51 PM
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slipknot 26
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Originally Posted by edh13
It never fails!!!
That thing must fly like a Bullet!!!!
Old 09-22-2014, 02:57 PM
  #73  
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Originally Posted by slipknot 26
That thing must fly like a Bullet!!!!
And loud!!

I was thinking of the "muffled" tuned pipes, which I think are quite a bit longer. Has any one done that?

Jim

Last edited by jrf; 09-22-2014 at 03:00 PM.
Old 09-22-2014, 03:41 PM
  #74  
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http://www.hobbyhangar.com/hhbaseline_002.htm
Old 09-22-2014, 04:23 PM
  #75  
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Originally Posted by jrf
You may be the first to run tuned pipes on twin nacelles. They would tend to stick out past the trailing edge a bit.

(Now someone will come up with a photo showing that it has been done, I'm sure.)

BTW, the King Cobra is a Sig kit of a larger size Kougar. You would still be adding 3+ pounds to it, but at least the basic airframe would start out with more capacity to carry it.

Jim
I've had an idea going on for a couple years that I haven't done anything meaningful with (except to buy engines) where I start with my Shadow design and cross it with Dave Platt's Duellist for a total of 3 engines - all piped. The engines were supposed to be OS CV-A's but they're out of production and I have one new one and one well used one so I'm at least one engine short.

So I bought NovaRossi .15's which are way heavier than I want to use.

But yes, the pipes are a problem as the wing chord will be about 8" where the engines mount and most of the pipe will hang off the back of the wing. I was looking at 4 to 4.5 pounds ready to fly with retracts.

The only solution I think might be possible will be to rotate the engines so the pipes mount to the fuselage sides. I haven't put it on paper to see how it would work exactly but the project is dead anyway unless I can find some lighter screaming .15's. The NovaRossi's are too big and too heavy. I have a Webra Speed .32 that's about the same weight - I think slightly lighter than the NovaRossi .15s.

------------------------

The King Kobra would be nice with the twin .55's I think. Or maybe three of them.

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