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Post by Garf on Jul 3, 2011 12:49:45 GMT -7
Strap on muffler proved a little too heavy. it's a little too sensitive with the muffler removed. I reduced the elevator travel without the muffler. That helped a little but doesn't feel right. I will try a light weight muffler then adjust elevator travel to suit.
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Post by Garf on Jul 3, 2011 20:19:59 GMT -7
I put a DuBro muffler on it. I also mounted a TT 11-4.5 prop on this thing. The Brodak is supposed to like that prop. Time will tell.
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Post by Garf on Jul 10, 2011 13:50:21 GMT -7
It likes the 11-4.5 prop. Mileage is down a bit. I played with elevator throw. CG is close to right.
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Post by Garf on Jul 17, 2011 20:29:58 GMT -7
The Brodak 40 never did preform as I would have liked it to, so I swapped it for an OS LA 40. Now we'll see if it was the engine or something else.
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Post by Garf on Aug 14, 2011 12:21:45 GMT -7
The Profile NoblARF now has an LA 40 and Taipan 11-5 prop plus a soda can muffler. It feels heavy and sluggish compared to the original ARF as it comes from China.
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Post by Garf on Aug 21, 2011 17:35:15 GMT -7
I put up a flight on the Profile NoblARF today. It is sluggish turning, so I ended up planting it in a low pullout of the reverse wingover. The fuselage split aft of the wing, for the second time.
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Post by blklion on Aug 22, 2011 7:21:16 GMT -7
Man! I've seen that lots of times before and it always resulted from not paying attention to the grain of the fuse balsa. One "solution" was to make a new fuse out of two 1/4" balsa slabs glued together. Another was to cover the fuse with silk or heavy silkspan. I made one "field repair" using popsicle sticks, gauze wrap and lots of Ambroid. I flew that plane for a couple of months like that and it held up fine even though it was uglier than I am.
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Post by slobmaster on Aug 22, 2011 8:20:09 GMT -7
That break is almost identical to my clown's fuse when I pancaked it in after I lost tension coming out of the back half of a figure 8. When I lost tension, the clown went into a free flight wingover, and coming back down on the other side, I caught tension just before nosing in. Still working on it, fabricated a "built-up" fuse for it. ;D P/S it had one of your aluminum spinners on it, and neither it nor the prop suffered any damage. Bennt the LGs though!
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Post by Garf on Aug 22, 2011 9:58:35 GMT -7
I almost, but not quite made the pullout upright. The landing gear caught the ground, tilted the plane forward, the muffler dug in, then the fuselage broke. The flap horn bent slightly. I need to check the engine mounting bolts to see if they bent.
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Post by slobmaster on Aug 23, 2011 1:24:33 GMT -7
I'm seriously thinking about using a single wheel LG like old timey combat planes I used to build. ;D
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Post by Garf on Aug 23, 2011 12:57:04 GMT -7
I had single wheel gear on both the PT-19 and the Galaxy at one time. I used them until I figured out a way to install 2 wheel gear on one side of the fuselage. The down side to the single wheel gear is the outboard tip gets some rash after a while. Galaxy
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Post by slobmaster on Aug 24, 2011 6:15:50 GMT -7
Hey, cool idea........no more wing removal for new LG. ;D
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Post by flyingtigre on Aug 24, 2011 13:36:26 GMT -7
Hey, cool idea........no more wing removal for new LG. ;D Another method is to drill a single hole thru the fuse and insert a short end 1/2 way thru from each side. Passing a piece of fuel line thru the fuse and inserting the end of the music wire into it also provides a sort of shock absorber. Don't know who it was that told me that one - it's not original. ================================================ This was the method I used to use. A single tube would break on impact and tear up the fuselage. A double tube would hold, but would sometimes bend. Brodak currently uses this method on the wire gear they sell.
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Post by slobmaster on Aug 25, 2011 15:10:22 GMT -7
Hey, cool idea........no more wing removal for new LG. ;D Another method is to drill a single hole thru the fuse and insert a short end 1/2 way thru from each side. Passing a piece of fuel line thru the fuse and inserting the end of the music wire into it also provides a sort of shock absorber. Don't know who it was that told me that one - it's not original. ================================================ This was the method I used to use. A single tube would break on impact and tear up the fuselage. A double tube would hold, but would sometimes bend. Brodak currently uses this method on the wire gear they sell. I need to know these things....makes my choices more complicated! ;D
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Post by Garf on Aug 25, 2011 20:47:54 GMT -7
This is my final variation. The fuselage holes were supposed to be side by side. This is strong enough that this has already been thru a pancake crash that folded 1/8" music wire back 45* with little or no damage. These are "after" pics.
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Post by blklion on Aug 26, 2011 3:33:40 GMT -7
One of the questions that comes up in the conversion of an inverted engined model into a profile with side mounted engine is the engine thrust line and vertical CG. Since you are taking the cylinder and raising it in relation to the centerline of the fuselage, that raises the vertical CG. In theory, you need to drop the engine centerline to maintain the CG in the same spot. BUT that changes the engines thrust line. What difference that makes if any, I don't know. I might be better off to hang a massive muffler on the engine and heavy wheels and leave the engine C/L where it is. Any thoughts? The vertical CG line is affected by engine offset (under power), rudder offset (while in motion) and leadout position. The vertical CG line is the line on which the airplane rotates horizontally. Engine orientation does not affect the vertical. The lateral CG line is the one that runs through the wing and is more often called the balance point or BP. Engine orientation (fore or aft) will affect this but rotating the engine will not. The CG line that does become affected though is the linear line which is, ideally, the same as the thrust line on stunt models. With a sidemount engine you placing more weight to one side of the linear line; normally the outboard side, and you'd then need less tip weight
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Post by Garf on Aug 26, 2011 8:45:55 GMT -7
I can't say I follow this, but I do know that a plane must be balanced on all 3 axis to fly right.
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Post by blklion on Aug 26, 2011 10:51:08 GMT -7
[quote author=garf board=wire thread=3621 post=37815 time=1314373555 I can't say I follow this, but I do know that a plane must be balanced on all 3 axis to fly right. [/quote]
That's true with an RC model but not so much with a UC or tethered model. Only two of the CG lines (through the fuselage length and through the wing) are affected by gravity and need to be balanced with weight. The vertical line is "fudgable" using engine offset, rudder offset and leadout exit on the wing. You aren't trying to achieve balance so much as to achieve a comfortable amount of line tension.
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Post by Garf on Aug 28, 2011 20:24:15 GMT -7
Well, I did it again. Flying after some rain, everything was wet. The plane came in on the lines, went back out, and pulled the handle right out of my hand. It hung on the thong, I recovered the handle, but not in time to regain control. Yard dart. Fuselage broke back of the wing again. The glue is already drying. I wonder how many times I can do this without destroying it?
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Post by jehold66203 on Aug 31, 2011 12:20:39 GMT -7
Sounds like you need to get a better grip on things. Ha ha ha Just kidding as I had my Brodak Nobler pull/yank the handle from my grip. Inboard wing was litterally destroyed.
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