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Old Dec 02, 2010, 04:33 PM
WMD
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Mako Pusher - Depron twin boom ROG design

I am about to build a twin-boom pusher depron parkflyer, christened the Mako Pusher.

This, like my Project Bolo thread - http://www.rcgroups.com/forums/showthread.php?t=1192121 - will be a small cheap foamie and designed to fly in a (very) small park. I want this plane to be able to belly-slide in on grass with no u/c gear, and also hopefully to do ROG take-offs that way too. I'm not trying to build something fast or aerobatic, just something that cruises around gently, and looks good doing it.

I was inspired by some great pics I saw of the new Boomerang Torus - http://www.boomerangjets.com/us/torus.html - which is a very big jet turbine (model) plane and costs slightly more than my car did. Apparently they were going to call it Mako, but then settled on Torus. I love the pics, but I don't fly turbines, I fly cheap, small, foamie parkflyers. Accordingly, I used Sketchup to model it and then twisted and bent it until I'd got a 1m span foamie that would (hopefully) belly ROG. It now has pretty much none of the Torus design left to be honest. It's much less pretty now.

Span will be just over 1m. Construction will be 6mm depron. I plan to use the same BL motor and prop that I have here from the Bolo - its the stock powertrain from an AXN CloudFly (now deceased), so it's a 2200Kv motor doing something like 145W with a little 5x5 pusher prop. Powered by a TP 1320 3S Lipo.

Another option would be a 6x4 prop with a bigger motor - say a A2212 -6T for 200W - there is plenty of clearance in the design for that.

If anyone wants the Sketchup file, just shout out.
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Old Dec 02, 2010, 04:53 PM
WMD
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For reference the very very nice original inspiration Boomerang Torus looks like this: Pics are from - http://www.rcmf.co.uk/4um/index.php?topic=75761.0 - my design of the Mako Pusher started from here and then went downhill and got much, much uglier when I started to drop the nose and make it a high shoulder wing model, to get the prop clearance needed when sliding along the grass.
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Old Dec 02, 2010, 07:53 PM
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Looks kinda like mine. It was a great flyer. Too bad it's on the ceiling now. I'm sure you'll love yours.
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Old Dec 03, 2010, 07:57 AM
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First, how about posting your sketchup files so we can have a chance to mess with it .
Second, you need to reinforce your booms you will get a lot of vibration the way you have it set up. You could extend the section of the wing back to the vert stab or run a seperate peice from about the middle of the wing back to the vert stab at the middle of the boom section, either way this will give you the stability you need. As I recall the cloud ANX Clouds Fly has a 50 inch wing span and is a real "floater" I am guessing you are going for more of an aerobatic plane. What size are you shooting for using the gear from the deceased plane. It looks like it will to be around 42 inches and probably lighter.
Third, This looks like a good Candidate for a KF - Kline Fogleman wing. It will stiffen it up and give you more lift. One more thing about the wing it looks like the incidence it off between the wing an horizontal stab Wouldn't you want them inline on a foamie? Maybe it's just the perspective, but they liik out of alignment (too much incidence on the wing)
You can see why I want your sketchup file - I can't leave anything alone
I'd actually like to build one - Just got a new bundle of Bluecore and am looking for a new project (after the three already in process).
Thanks, Good Luck
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Last edited by MIJohn; Dec 03, 2010 at 08:32 AM.
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Old Dec 03, 2010, 08:34 AM
WMD
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Here you go MIJ, sketchup file is here.

Thanks for the thoughts.

As far as strengthening the booms goes, the drawings posted as yet aren't that clear, but I have the booms as a double thickness of 6mm, so that's 12mm total. I'll try it that way first and see how it works out, for stiffness.

The design is 1060 mm in span. Like I said, I'm not trying to make it aerobatic, just to look good cruising around. If that means I end up flying on 1/3 throttle all the time, that's ok. Will be quieter that way, too.

I'm not a big fan of KF wings, so will just do it flat plate, but do I agree the wing could do with a CF spar buried in there for strength.
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Old Dec 03, 2010, 08:45 AM
WMD
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Yeah the wing incidence is deliberately like that, it is a bit experimental. I don't know if it will work well, yet. I'm hoping the plane will fly with a slightly nose down attitude, but it's the stance when she sits and slides on her belly that I have been tweaking. Need to generate lift when attempting ROG from grass. Almost like permanently having flaps in down position. I had this issue with the Bolo, and am trying to this time get lots of lift right from the start.

It will all get chopped and changed later, no doubt.
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Old Dec 03, 2010, 10:19 AM
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Actually I take that back, you have a good point. I have added some fillets to reinforce the booms, 30mm wide at the wing trailing edge, tapering down to nothing at the rudder hinge line. Can't hurt with strength, and it's not much more weight to add. I think it looks right, too.
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Old Dec 03, 2010, 10:32 AM
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Keep in touch and see if you can video it - I really like the look and can't wait to see it in the air.
As far as the incidence goes in my experience is, if left as is, you will be constantly using down elevator to correct the lift.

By the way, I like the droopy nose and think it adds character and style but the elevator REALLY needs to be inline or they fight each other. I did what you are trying on a 2meter glider I built, and I had to realign it. It kept climbing and would not stop. Almost couldn't get it down! Granted I had much more lift, but, you can understand what will happen. Flat Fomies have virtually no lift and it is incidence that makes it fly. If the horizontal surfaces are not alligned they will fight each other and the bigger one will win! Always. I think it will do a bunch of really neat loops. Take Care, and Best of Luck
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Old Dec 03, 2010, 12:04 PM
WMD
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If it flies, I will be sure to get some video. Nothing quite like video to share ideas.

You may well be right. Me, I'm not sure yet. If you are right, and she turns out unflyable in that way, I will cut off and reglue the tail stab with incidence to match the wing. I guess the only way to know for sure is to get on with it, build it and try flying it. Hopefully this weekend I can get on with this.
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Old Dec 03, 2010, 12:53 PM
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I love dual boom pushers. You guys might want to check out our build thread on a dual boom pusher called the "So". Originally designed by a guy named Foam Flyer but we've morphed it into many of our own variations. These planes are easy to build, tough, repair easily, and fly like no other plane I've ever flown. It's hard to explain until you fly one, not to mention they look cool in the air. Foam Flyer's website has other variations on this theme as well, many of which look very much like your design in this thread.

While his construction method and ours centers mostly around hot wiring EPS foam, some guys in the thread have built flat foam and even balsa versions of it. I prefer EPS myself, as construction is easier and faster than flat foam so long as you have some basic hot wiring tools. We even go into detail on building cheap/easy hot wire tools with parts you probably already have laying around in your garage. Really you only need a hot wire bow, and you can build one in minutes and power it with a car battery charger. Extensively details are provided in the thread, and we walk you through cutting out wings using airfoil jigs (easy) and every other aspect of building this plane and with EPS.

Not wanting to hijack your thread here, just wanting to let you guys know that a lot of information exists on dual boom pushers for those who are intrigued by these designs. Here's the thread...

http://www.rcuniverse.com/forum/m_69..._1/key_/tm.htm

And here's some pics of just some of the builds found there to peak your interest...
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Old Dec 03, 2010, 05:23 PM
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Excellent. I love the pics. Interesting stuff, I will read more on the work you've done. I do remember a couple of years ago reading a thread with lots of epp twin boom pushers all with just one aileron - I guess that was you. Nice work.

Edit - Hey yes, that's him, Foam flyer over at - http://www.foamflyer.info/ - I love those planes. Nice choice of schemes too, with Russian, German, etc etc. But the designs are key. Beautiful designs. Hats off to FoamFlyer. Good work, fella.
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Last edited by WMD; Dec 03, 2010 at 05:36 PM.
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Old Dec 03, 2010, 05:51 PM
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I like it WMD, good luck with the build. Definitely get us some pictures and videos.
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Old Dec 03, 2010, 07:11 PM
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GREAT JOB WMD. Work on her she will fly good.

Here's mine.

Twinax pusher prop scratchbuild (2 min 29 sec)


HOPE THIS HELP.

ALBRT.
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Old Dec 04, 2010, 03:08 AM
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my beast was mod / bash of a airhoag titan chuck glider.

i chopped tail and made twin booms.

she partly in foam heaven now ..
but may come back as a canard jet pusher.
8x4e on a tp 2409 12T 1350 3s 35c

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Old Dec 04, 2010, 03:48 AM
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prime8 that is very cool!
Doy ou have a link to your build log?
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