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Old Nov 25, 2008, 08:38 PM
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RC Bachem Natter, pusher or rocket powered...

Always wanted to do one of these, now that I figured out how to do the rocket ignition reliably, and have a bunch of E-6 aerotech reloads on the way, and since I made my X-15 electric pusher module and rocket module able to move from model to model, I decided I'd do a natter. I'll do an xform fuse/wing and a full flying tail for simplicity, with a 24mm rocket for vertical launch or pusher. It appears that I might move the wing slightly rearward based on some things I've read and on the three view, might be hard to get the CG right without a lot of extra nose weight, we'll see. I already have the thruster rocket pods built......

Frank
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Old Nov 25, 2008, 10:29 PM
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You never quit do you? I'll be watching!
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Old Nov 26, 2008, 12:26 AM
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Well, I didn't do anything for 6 months, I figure it was about time

Here are the profiles drawn on depron ready to cut out with the electric pod layed out, with the electronics, I fudged the wing back about an inch, added about 1/2" to the chord and a little to the wingspan so it still looks right, but gives a bit better chance of making cg without adding lead. Looks like it should be very similar to the X-15 in size and area/weight.

Frank
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Old Nov 26, 2008, 04:58 AM
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You never quit do you? I'll be watching!
No he doesnt...projects are like bowling pins...line them up and knock them down!!
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Old Nov 26, 2008, 11:11 AM
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Well, if he build a real one it would take Frank all of a week to complete, to long, so he just keeps building models.
Steve
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Old Nov 26, 2008, 11:49 AM
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:>) Well, as I do more, I learn more and discover ways to make things work that I thought were impractical before.. they just kind of fall into place sometimes.

Couldn't sleep, so here's where I'm at, parts are cut and traced for plans, glide tests done, looks like 30% is about right for CG, and I try fit the parts together, it's looking really good so far I think, 30" long and 18.5" wingspan.

Frank
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Old Nov 26, 2008, 02:46 PM
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Frank, are the fuselage rockets going to angled out? Also, you'll need to fill the nose up with bottle rockets to make it really realistic.
Steve
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Old Nov 26, 2008, 04:03 PM
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Frank
your draken was awsome ,there are plenty of gripens around , what we need is a viggen
John van den Berg
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Old Nov 26, 2008, 04:56 PM
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Fuse rockets will be angled out but they are just for show and are undersized because the servo to drive each stabilator will be in the way if they were longer. Bottle rockets.......

Frank



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Frank, are the fuselage rockets going to angled out? Also, you'll need to fill the nose up with bottle rockets to make it really realistic.
Steve
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Old Nov 26, 2008, 04:58 PM
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Thanks, I'm bummed that my draken was killed due to a spektrum un-bind in the middle of a split ess(pointed straight down of course) during our RC airshow this summer. My radios are full, but I'll see what I can do with a Viggen in the next month or so....maybe I can design the airframe and you can do a beta build for me, that way I don't have to canibalize one of my other planes??

It only takes me a day or so to draw up plans, usually I've got most of the problems figured out, and can do test glides with a full size foam only shell...

Interested??

Frank


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Frank
your draken was awsome ,there are plenty of gripens around , what we need is a viggen
John van den Berg
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Old Nov 27, 2008, 12:25 AM
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Here it is almost finished, need to do some touchup painting, and maybe do some more detail, but good enough for a toss tomorrow before I head up to Seattle. Came out at 12 oz with electric, maybe a half ounce less with composite E-6.
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Old Nov 27, 2008, 06:09 AM
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"Hang on to her Newt....she'll only buck for a little while!" Those are the famous words of my sim partner while I trying to handle an engine out.
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Old Nov 27, 2008, 11:28 AM
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Test hop....

Well, I wanted so bad for the CG to be where it was without adding nose weight, that I kind of glossed over a little pitch up tendency in glide tests....

It was one of those handlaunches where it pitched up vertical hung there, and went into a torque roll, fun if you aren't at the controls......I managed to get it down flat on a lucky oscillation. Nose now has more of a wartime finish.

I moved the CG forward 5/8" and it now flies well. Handlaunch at 60% is easy, purple peril has plenty of power. I was worried about the tailerons being above the thrust/wing axis and not having much effect, however they seem fine, it rolls like a madman to the left, but to the right is slower, only issue on a full roll to the right, it gets inverted and slows and kind of gets stuck there, if you are too slow in loops/rolls, it plops back upright, due to the battery on the bottom, I think. Landings with power on are pretty slow and docile, glide isn't floaty, as there is about 1 square foot of wing area or a little more for 13 oz rtf, just keep the nose down to keep speed so you can flare at the end. It looks great in the air.

I'll try a rocket flight on Sunday when I get back, enjoy the holiday everyone.

Frank
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Old Nov 30, 2008, 02:11 PM
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Old Nov 30, 2008, 02:37 PM
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A little foggy! Great job, I thought it would be going faster, but you are launching 13oz. You are right, it doesn't glide much at all. Well done. I finally have my APC 7x4 pusher on and now I am just waiting for the weather to cooperate. It's snowing today.
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