Electric Ducted Fan Jets Discuss electric ducted fan jets here including setup tips, power systems, flying techniques, etc.

Bobcat ducted fan conversion

Old 01-31-2008, 08:15 PM
  #1  
glider pilot 1111
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Default Bobcat ducted fan conversion

I have a new project on the table. It's a Bobcat 52 from Nitro Planes.
It's designed for a 50 size nitro. Those silly guys. I'm putting a 4.5" ducted fan and 12 cells on it. If it holds together it will put the nitro boys to shame. Moto Calc est. is 168 mph. Not bad for a $100 ARF.
Pictures and setup info to come.
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Old 02-01-2008, 06:59 AM
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Larry3215
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Sounds like fun!

larry
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Old 02-01-2008, 08:52 AM
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Shing Kan Zen
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more info & photo pls.
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Old 02-11-2008, 01:30 PM
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kp647
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you may want to look at this thread on ezone, my brother is working on a similar project

http://www.rcgroups.com/forums/showt...ghlight=bobcat
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Old 02-14-2008, 07:06 AM
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Default Bobcat mods

I've been working on my Bobcat and have ended up highly modifying it. One of my good friends has a c n c router, so we decided to get some use out of it. He machined up an aluminum heat sink for the motor and is now working on a carbon fan mount.
I plan on using a cradle to takeoff, so this takes over a pound of wood and retracts out of the plane. So far on the Bobcat I've removed all the unnecessary wood in the fuse. To add strength back in I placed a strip of carbon fiber on the bottom of the fuse. Since I'll be belly sliding in I needed to put the aileron servos on top , so I placed them inside the booms. I needed to cut a notch out of the boom , so I fiberglassed the inside of the boom to strengthen it. This will also help with drag.
Final mod so far. We decided it needed a removable canopy, so today I wrapped the inside of the canopy opening with balsa and glassed that in.

It's coming along!
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Old 02-14-2008, 07:27 AM
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Default Bobcat set up

To power this Cat I'm using a 4.5" fan and a KB45-17XL from www.hobbycity.com . I'm also using their low profile mg aileron servos on ailerons and rudders. On the elevator I needed a small high torque servo, so my bud helping me with this project gave a small JR digital. O ya.... I also modified the elevator and put the servo inside the horizontal stab.
The only exposed servos are the rudders and I think I'm going to mold covers for them. Erasing as much drag as possible. Batteries are from www.maxamps.com 2- 6s 4000mah in series.

This Bobcat should move !!
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Old 02-14-2008, 07:30 AM
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Thanks for your bros link. I'd link his opinion on my mods.
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Old 02-14-2008, 04:37 PM
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Alpea42
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Nitro Models are so darn cheap you can't buy the material and glue and covering and build anything as cheaply.That looks as good or flys so well .My flying buddie has the foamy Me 109.And I've seen Chellies Funtanna.12 cells on a edf "good golly miss molley" hope it holds together
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Old 02-15-2008, 07:40 PM
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Originally Posted by Alpea42 View Post
Nitro Models are so darn cheap you can't buy the material and glue and covering and build anything as cheaply.That looks as good or flys so well .My flying buddie has the foamy Me 109.And I've seen Chellies Funtanna.12 cells on a edf "good golly miss molley" hope it holds together
This is my 3rd nitro plane and I've seen others and they all look nice and fly great. Like you said , the price can't be beat. I picked up the Bobcat off one of their sales for $99.
I'm building this plane on the cheap. Most of the gear is from hobby city,
also amazing prices and the quality has been top notch.
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Old 02-15-2008, 09:56 PM
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Larry3215
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How are you going to mount the fan? Pod or pylon or?

Interesting project!

Larry
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Old 02-16-2008, 04:58 AM
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We'll be cutting the mount next week. I'll post pictures asap.
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Old 03-02-2008, 04:39 AM
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Default DF mount

We finally got around to cutting the fan mount. We wanted to make sure it was perfect before cutting it out of carbon plate. We used plywood for our test mounts and came out with a really nice mount. I still need to trim the bolt ends off, but over all that's it.
It's in the final steps now. Just need to finish the servo extensions and
canopy. Which is about time enough for the snow to melt.
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Old 03-02-2008, 06:40 AM
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That looks wicked!

Larry
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Old 03-02-2008, 07:13 PM
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Bill G
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Originally Posted by glider pilot 1111 View Post
I have a new project on the table. It's a Bobcat 52 from Nitro Planes.
It's designed for a 50 size nitro. Those silly guys. I'm putting a 4.5" ducted fan and 12 cells on it. If it holds together it will put the nitro boys to shame. Moto Calc est. is 168 mph. Not bad for a $100 ARF.
Pictures and setup info to come.
Here's my idea. Radically rework the hell out of it too look like this:
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Old 03-02-2008, 08:49 PM
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WOW,is that a Bobcat?? What's your power plant? How's the speed?
Even after cleaning mine up, I still think it has enough drag to keep me way below the est. speed. Still should be an Adrenalin pumper.
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Old 03-04-2008, 04:49 AM
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Originally Posted by glider pilot 1111 View Post
WOW,is that a Bobcat?? What's your power plant? How's the speed?
Even after cleaning mine up, I still think it has enough drag to keep me way below the est. speed. Still should be an Adrenalin pumper.
Its not a Bobcat, actually a bash made from GWS A10 nacelles and a GWS ME109 fuse. Fast and beautifully performing plane. Definitely turned me on to the performance of the twin boom Bobcat type design though. I've thought that some of the Bobcat type foamies could be bashed into one of these. Couldn't be any more difficult than making the fuse out of GWS A10 nacelles.

The plane has an EDF55 with Himax 2025-5300. Almost wish I had built it with an EDF64, but its fast enough.
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Old 08-29-2008, 09:31 AM
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Default conversion to edf

Please let me know whar edf system you made conversion with and where to buy. I am from South Africa and must buy things from overseas sometimes cause it is not always available here.
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Old 08-29-2008, 06:10 PM
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glider pilot 1111
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I purchased the fan and motor from www.hobbycity.com

It's under " Parts & accs. " then " props, EDF ". If your looking
for cheep packs to run it. I've bought a few large Zippy-R LiPo's
from hobby city and they are running really strong. The Zippy-H
has even more power.

I'm running mine on 12s, I think they recommend 10s. My competition
season is almost over, so I'm looking forward to getting back on this project.
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Old 12-17-2008, 08:53 PM
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glider pilot 1111
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Default Bobcat flys !!!!

I started this project almost a year ago. Then life got in the way.The
Bobcat sat doing a fine job of collecting dust. Well, I finally got a
chance to finish it. Still has a few bugs, but here's the video of it's
first flight.

[media]http://www.youtube.com/watch?v=Smll-fmpQo4[/media]

Enjoy
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Old 12-18-2008, 01:32 AM
  #20  
Larry3215
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I did a dopplar of your one low pass and it reads around 89mph or so. Not bad for 1/2 throttle!

Congrats!!
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Old 12-18-2008, 01:59 AM
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Nice! Now get it dialed in and see what it can really do!!!
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Old 12-18-2008, 06:05 PM
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Alpea42
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Congrats on the maiden. Mini Steve flew a Falcon 25 at 4lbs. 10 oz with a Turnigy SK series 40 sized motor on 4 cells. Can't believe yours flys that well at 10 lbs. It was Stryker kinda fast 70 mph ish. in a 1/10 mi. sq. field which was too small and he had to land at about 45 mph which ended up knocking the gear off . And he says it's fixed but he hasn't tried it again yet. The camera man only got the take off cuz he had to help with the torque rolling issue. I think this is the same plane , his is called a Falcon 25 so maybe it's smaller. Yeah I guess it is the little brother to yours. But here's the take off. http://www.vimeo.com/2190890
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Old 01-26-2009, 10:07 PM
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glider pilot 1111
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Originally Posted by Larry3215 View Post
I did a dopplar of your one low pass and it reads around 89mph or so. Not bad for 1/2 throttle!

Congrats!!
We were guessing around 80 to 90 mph. Now the big ???

How the heck did you figure the speed from the video.

Thanks
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Old 01-27-2009, 03:11 AM
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There are a couple of different free programs available that will let you capture the audio portion of the video.

You can calculate the speed based on the dopplar shift in the frequency of the sound coming from the fan unit or prop. The software does most of the work on that for you automatically.

Its pretty nifty actually

I use a free version of WaveoScope:

http://www.sprut.de/electronic/soft/scope.htm#download

There is also an english language version if I can find the link....

http://www.happykillmore.com/downloads/WOS.zip

The english link does not seem to be working at the moment - sorry!
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Old 01-27-2009, 03:32 AM
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I converted the falcon 120(big bobcat) to an byron fan setup. i have sence sold the nitro engine and researching to convert it to electric.
The plane are great flyers. so i didn't want to give it up.
i have video of the nitro setup.
another flyer at my feild is doing large EDF and i am watching closely
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