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Old Nov 22, 2011, 07:37 PM
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Boeing X-32B 120mm (Maiden part 2!)

Ok,

I know that everyone following Bill's X-32A build was heart broken when we heard about the non-flying damage to his model. The X-32 was my first attempt at CAD design and never completed, too many CAD errors . I moved on to other projects but I have always had a soft spot for the X-32. Pre-CAD, I have designed and built 2 of them. The first was a 70mm model in about 2001 and the last one a 90mm one in 2004?

I figured that I need to go head and press on with my newest version.
67" long and 45.5" wingspan. This works out to over 1300sq. in. of wing area. The planned unit is a 120mm unit (Turbax in a Haoye shroud with the Turnigy 4030-800 motor, ala Knife Lee). The plan is to fly it on 10-12cells and a design weight goal of 14 lbs or less.

Planned features, rotating main landing gear and depending on space, maybe a rotating nose gear too. The rudders will deflect inward, like the full scale on to add in pitch control during takeoffs and landings.
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Old Nov 22, 2011, 07:58 PM
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EDF Jet Jam 2015 , May 28-31
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My concerns with the project is the CG. My 70mm X-32 flew fine but landed hot...nose heavy and the last flight I moved to CG too far aft and it was destroyed when a model eating tree got it. The last one, 90mm, never really flew right. I blame some of it on the CG too. I remember one flight when it was flying pretty good but when I throttled back to land, it just stopped flying, dived and finally started to pull out at about 10 off the ground....about 2 feet too low . I both cases I was using a fully symmetrical airfoil, this time I did some experiments and opted for the Zagi (reflexed) airfoil. Now both of these models were bungee launched so I could get to flying speed in .2 secs this won't be the case with this one so I will be doing a lot of testing and compiling data on CG location for various delta models.
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Old Nov 22, 2011, 08:19 PM
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This is one of the few modern planes that's attracted me, probably because it didn't make it to the same front line fame as others. Always like the oddballs.

I imagine just setting the CG may be difficult, as the ideal fan location can end up where you want the battery. It's good when you've built a few before, as you gain a better idea of the ideal locations for everything. I've had a few where the end result was a good bit different from what I first had in mind, to the point of wanting to start a new thread.

That plane is big. When you're used to building in the 3ft range, a simple 4 footer knocks everything off the table. I'm not set up for large builds, and a simple airliner fuselage has forced a bit of bench rearranging. At your scale, the structure becomes so much more efficient, that the final loading should be beautiful. There's a lot of open area and material that can be removed with formers that large.
Bill
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Old Nov 22, 2011, 08:45 PM
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Whoa! now that's big, took a whole balsa tree to build.
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Old Nov 22, 2011, 09:07 PM
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Yikes that big...

Are you planning on mounting the packs side by side e.g like the fuel setups? I've seen a few Balsa USA force one conversion with the motor mounted mid cord, and the packs need to be moved pretty far back to hit the cg.

Way glad to see ya post a new project... !!!!

BTW, who did you use for the laser cutting?

Bob
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Old Nov 23, 2011, 12:55 AM
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very cool. can't wait to see it fly. deffinitely, 100% subbed to this one.

Rich
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Old Nov 23, 2011, 01:16 AM
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Yes Indeed Rich! this is gona be a great thread, I remember when the Boeing X-32B was in competition with the X-35 which is now of course the F-35, I will be following this build as well Subbed-up!
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Old Nov 23, 2011, 02:31 PM
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EDF Jet Jam 2015 , May 28-31
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Thanks guys!
Bill, I also like the odd stuff that is why I like your user name here.
Bob, the packs will go into holes on either side of the fan. My rough calculations. says I should hit my cfcg at 20% of MAC. The guy that does my laser work is AK -Models.
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Old Nov 23, 2011, 04:05 PM
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Kevin,
A very nice project for sure... and happy to know Alex is still operating, he does good work.

The reason I mentioned the Balsa USA deltas (I've had a few of them), the mid engine mount still resulted in a tail heavy setup, and a bear to get enough of the bits far enough forward to hit the CG... but then again, you are the master of custom builds...

Thanks for sharing... and looking forward to see this bird take flight!

Bob
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Old Nov 23, 2011, 06:40 PM
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Been waiting for this one for a while....

Good luck Kevin.

Eric B.
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Old Nov 23, 2011, 08:24 PM
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EDF Jet Jam 2015, May 28-31st
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Hi Kevin,
Dang, when you mentioned on the phone that it was big, you weren't kidding. I can see now how the wing root can be 3+ inches thich and not be that noticable.

Dan Eaton
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Old Nov 23, 2011, 10:05 PM
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Looks great Kevin,

Incredible size, do you think it should help with stability at the larger size?
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Old Nov 24, 2011, 11:57 AM
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Bob, ending up tail heavy is still a concern but it usually is with me regardless of the model . My flight packs will be adjustable and the packs for the RX and retracts will be in the cockpit. This leaves the 8 servos, main retracts, struts and fan unit all aft of the CG. But I have a plan 'B', that fan can be slide more forward IF required.

Dan,
It is back in the basement where it doesn't look so big. Carrying it up the stairs will be challenge once it is complete.

Jeff,
I'm hoping a lower wingloading will help. I have also decided to reduce the amount of anhedral which should help with roll stability. All this should make a better flying ship.
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Old Nov 24, 2011, 09:25 PM
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Have Fun! Land, Sea or Air
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Nice work, signing up for this one as well.
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Old Nov 25, 2011, 10:37 AM
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Third time is charm, Kevin. I'm sure you're refining your design as you proceed on to a new version as well; and scaling up is not as big a job on CAD compared to hand drawn Its coming along fast. Nice project.

I've also sent a laser cutting job to AK-model & hope to get parts back soon. He took the time to spell out in detail how he needs a CAD package to be prepared for cutting on his site. I like that.


Phil
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