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Old Apr 27, 2015, 05:25 PM
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Judy Jet Ski 2X

A while back I saw a set of the cutest little planes presented by Jugen Bestenlehner.
ref http://www.rcgroups.com/forums/showthread.php?t=2321902

I asked him if I could start making them here in the USA .
Since we both agreed that shipping was too high to compete on
the other side of the pond it was decided that I would
sell only in the USA.
Some time later Rusty-Gunn another RCG member chimed in an
let me know it was his original that Jurgen had modified.
I've added his name to the credits and apologized for the initial oversight.

So after I developed the cutting files for the small version
I decided that a little larger version might be ok.
It was so cute that I figured that 2X or 200% would
be a nice size so I plunged ahead in CAD and after a
short time headed out to the shop.
Well it turned out to be MUCH larger that I had anticipated.
Now a 46" span foamy isn't all that large but it consumes
5 full sized sheets of 6mm depron. But, I was committed ! ( or should be )

At this size I believe that Cute has been replaces with Comical.

The CG is just about where the rearmost hatch side rail ends.
Refer to Jurgens' original PDF http://www.vth.de/fileadmin/user/Zei..._Seajet_A0.pdf

Check out the layout drawings and then the pix of the cut sheets.
The wings were split so they'd ship in reasonable sized boxes.
While building I discovered a few things that need updating.
I intend to change the cutting files and add some TABS to help align
the Top and Bottom Fuse sides on the wing.
Also I did not "key" the tip floats and as a result have no idea
how I'm going to get them parallel to the flight path.
Again more tabs and slots will fix that issue.
Note: the layout show the changes now !

I used a single 6mm Carbon Fiber Blade bent and glued into the
curved Span Slot. It seemed a bit flimsy but I've Looped it a bunch
and done several dozen Touch and Go's with no issues.

By the way it is Slide On Ground capable as well as amphibious.
A Hobby King 3010b sized motor and a 3 blade 7x4.5 prop does
a fairly good job. Nothing spectacular but I didn't expect
verticals out of this design, what with all that drag.
it is spec'd at 420Watts.

I used a huge 60amp ESC but I've only measured a max of 27 amps.
Still it climbs out nicely. I suppose that the whole cockpit
could be enclosed if cooling vents are added.

I'm currently using an orange stability RX but I want to change
to one of my FrSky RX's so I can do some telemetry on my Taranus TX.
I have an amp telemetry module so I'll eventually get accurate inflight readings.

I've added a water rudder made from brass sheet and it flips up
if it strikes any thing. Pivot point is an old Nose gear steering block.

It's so windy that the vid on the water will have to wait another day or two.
Check out the maiden flight vid link. My reaction says it all.

Maiden Flight Vid - Proof of flight.
Judi JetSki (2 min 40 sec)


I kept expecting something to go wrong but it never happened.
I'm going to be flying it regularly for fun and to see if any
weaknesses develop.

In the meantime please find this as a CNC cut ready for assy kit on my web site .
If you are wanting to do your own cutting then let me know
and I'll send PDF or DXF versions of the layout for you use.

Please comeback as I will have updates soon and hopefully more vids.

Comments welcomed.

Best

Bob
Hoosier Cutout Service
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Old Apr 27, 2015, 08:03 PM
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Nice. Who said bigger isn't better!
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Old Apr 27, 2015, 08:05 PM
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wasn't ME. :-]

Nothing like shooting T&G's with something that you can see and "Feel" in the air. !
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Old Apr 27, 2015, 08:12 PM
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If you=re you are gonna use another guys design you could at least get the name on the thread name correct..??

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Old Apr 27, 2015, 08:20 PM
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Please allow for senior moments.

I have never figured out how to change a thread Title

As least I credited BOTH and got permissions.

geeez gimme a break here
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Old Apr 27, 2015, 09:03 PM
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My plans are in my blog
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Cool stuff. I figure Jugen can live with a mispelling. Me too. My alias is missing a 'g'.
This version ins't large. Its DANG large. You could put a person in that thing. Charge five dollars a ride at the fair. Cool. I'm next!
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Old Apr 28, 2015, 07:48 PM
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This evening was Magnificent !

I flew with the 4 cell 2700 pak and it was perfect.
Then I switched to the 3 cell 2650 pak .
Balance is right at the rearward limit now.
Though not as zippy it was still a very nice flying experience.

The BAD news:
Each flight was Hat Cam'd but although I checked for a flashing yellow light
I got ZIP ! :-(
I believe that the battery got "lazy" over the winter inside the Mobius.
There are tutorials for exchanging with a new cell on line.

More Bad News:
Although it flew with authority and panache off my neighbors pond,
his little Great Dane managed a collision with Yours Truly and I managed a
less than graceful landing. The taxi back was suspicious and SURE ENOUGH
the bottom had been compromised.
I WILL be adding a central/Keel support and possibly another former.
Still, NOTHING got wet as it's all so High off the water.

More as repairs progress.

L8r

Bob
Hoosier Cutout Service
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Old Apr 28, 2015, 08:58 PM
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Here I present the latest changes to the design.

For differences read the pic description.
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Old Apr 29, 2015, 03:21 AM
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It didn't want to collide, it wanted to bump you into the seat for a ride! Watch out, she's a mean one.
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Old Apr 29, 2015, 06:07 AM
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That dog is a threat to model aviation !
It wants attention EVEN while you are flying.
A 150# "nudge" saying I'm here, SEE ME , lets play!
Plus it likes to chase models during take off.
Evidence at this video ...
Sbach50 (3 min 38 sec)

And would also try to catch them doing approaches to the water
So high angle approaches made the pond a bit smaller.
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Old May 06, 2015, 10:30 AM
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Here I am a week or so later.

with an IMPROVED Judi "SEA JET" at 200%

It's the same model with a rebuilt bottom.
I put in an extra former and a Keel Former.
In addition I thought it might be interesting to try a Canopy.
So a whipped up a simple little Foamy canopy and just attached it
with some tape at the front for it's initial test.

A Vimeo Video will be up soon ( you know how they like to delay things. )
It'll be 42 mins form the time of this writing.
https://vimeo.com/127048470

I still find the Judi to be an excellent flier.
I also think it is faster WITH the Canopy.
But, that also points out a new wrinkle.
With the higher speed I am "feeling" a bit less control authority.
Stiffer control linkages are the remedy ,
but the quick fix is to back off on the power.
Fortunately I am PULLING on the controls for UP.

OK that's it for now.

Enjoy your summer flying.

Best

Bob
Hoosier Cutout Service
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Old May 06, 2015, 10:39 AM
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BTW
For those of you with smaller transport vehicles I am working on a 32" version
It'll be 6mm and pretty strong given that the 46" is from 6mm too.

Any interest ?
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Old May 06, 2015, 11:40 AM
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I had done another vid last evening but it was AVI format and Movie Maker didn't seem to want to work with it.
So I did a few screen grabs while watching and here are the cropped results.

Enjoy

Bob
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Old May 06, 2015, 05:16 PM
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32" ought to be a nice enough size. I figure it might be quite poular that size.
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Old May 06, 2015, 07:02 PM
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Well ... ???

Relatively is gonna be a little strange cuz NOBODY has been interested in the Big one ! :-(

I've been flyin it every day that I can !
Making little improvements along the way and loving it !

It's a Different flying experience and just plain fun.

I cut the 32" version today so maybe in a week it'll be ready for maiden time :-)

Summer has ARRIVED done here at THIS parallel !

L8r

Bob
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