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Building Tips and technical articles. => Building techniques => Topic started by: Steven Kientz on March 14, 2012, 05:08:15 PM
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I'm in the process of building a new fuselage for a Tutor II wing. I would like to stay with the 46 LA that was in it originally. What would be a good weight range for this engine? I'm getting close to finish sanding the fuselage, trying to decide if I can silkspan the fuse without it being overweight.
I didn't stay with the original shape. I really like the jet look(especially the Avenger). Its bigger than a fighter, so I'm leaning towards a fighter/bomber. I'm afraid she is a tad bit overweight.
When I get a little farther along I might post pictures.This is the first rebuild that I've done from scratch.
Thanks
Steve
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I would be inclined to say 50 oz, but there was one at GSSC a few years ago in a 65 oz USA-1 (well over 700 sq.) that did amazingly well in 80F + temps and near dead calm. :o Steve
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I'm in the process of building a new fuselage for a Tutor II wing. I would like to stay with the 46 LA that was in it originally. What would be a good weight range for this engine? I'm getting close to finish sanding the fuselage, trying to decide if I can silkspan the fuse without it being overweight.
I didn't stay with the original shape. I really like the jet look(especially the Avenger). Its bigger than a fighter, so I'm leaning towards a fighter/bomber. I'm afraid she is a tad bit overweight.
When I get a little farther along I might post pictures.This is the first rebuild that I've done from scratch.
Thanks
Steve
Silkspan on the fuse would not add any significant wieght, maybe 3 or 4 grams.
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thanks guys
I still have some places to reduce weight. Stab and elevator can be lighten ,besides some serious sanding on the fuse. I glued up 3x 1/4 " pieces for the fuse, trying to get away from that typical "plank' look that a profile has. My target weight was under 48oz. haven't weighed all the components yet, probably do that tonite.
Thanks
Steve
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I had a Profile Cardinal that flew reasonably well at 50 oz. with the LA46. I don't think for competition I would go beyond that weight for this ship using the LA46. Fuse was covered with silkspan. On mine the weight was to much paint.
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Weighed all major components 47.6 oz. Still needs 'cote and paint. Will probably lighten stab and elevator, cover in 'cote. tomorrow after work will get started on some serious sanding. New target 52 oz.
This is just a sport flyer, was hoping it would at least look nicer than my previous planes. Pictures soon.
Steve
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Here is a picture, I know the Lg is overkill, but trying to save my hobby $$ for the 3 skyrays .
Steve
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One more.
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I built a Scarinzi Blue Angel (630 sq in) many years ago that weighed 54 oz and flew very well. It was flown competitively at 10 VSC's and passed on to my friend Burt Brokaw who did some repair work that pushed the weight up to a little over 56 oz. It was flown at this years VSC (by Burt) and still flys very well. Ed Capitinelli has flown a Starduster 40 (his design) at over 56 oz with an LA46 and it has no difficulty at all, and flys an excellent pattern.
I wouldn't hesitate to use one in a 57 oz 640 sq in airplane and all mentioned above were flow in Tucson at 2200 ft + altitude and 100 degree temps.
Prop in most cases is APC 11.5X4 at about 9600 RPM for launch.
Lots of power to spare.
Most of the engines were reworked for stunt by me but nothing radical was done to them. Slight port reshaping (no timing changes), to direct charge to rear of cylinder. They lose less fuel out the exhaust port that way and use slightly less fuel overall. They probably do not develop any more power than stock but seem to be more tolerant of needle settings and perhaps give a slightly flatter torque curve in midrange.
They do run quite well however straight out of the box.
Randy Cuberly
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The Tutor II's that I and others had weighed 49 - 50.5ozs. with the heavy wire/large wheels landing gear that came with the kit. They flew well. Another flying buddy had a 62oz. Cardinal with a LA46 that flies great patterns, especially when Donnie Melancon and Steve Millet fly it. Sounds like you are in good shape to me with your weight.
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Found a pair of glass filled LG in the shop the other day. I am going to compare their weight to the Alum Lg I have and use the lighter of the two.I still need to recover the wing, fuse is painted(gray w/ 2 tone brown "camo").Added the "camo' after looking at all that gray for 2 days. Also need to paint the canopy black. Will get a final weight early this week.
Steve
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You will save a ton of weight if you dump the tube muffler and go with a tongue muffler.
You should be OK with 52 oz and the LA.
Did you keep the moments of the Tutor?
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The moments are close, did enlarge(longer) the stab and elevator. Might swap to a tongue muffler,pretty sure I'd have to buy one for the LA46. Low mpg truck and $4.00 gas has really put the hurt on my hobby funds(I'm sure we're all in the same boat, no Rockerfella last names on here).
Airframe is painted and ready to cover, just need a couple of hours shop time to get it done.
Steve
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When my P-39 was still flyable, the LA 46 pulled it with authority when the needle was right and the old man would fly it right. It weighed 65 ounces at VSC. H^^