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Bob Cat Copy Falcon 120 Jet

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Old 07-16-2008, 01:00 PM
  #1351  
TUMBLER
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Default RE: Bob Cat Copy Falcon 120 Jet

I don't have a way to measure the wing tube diameter exactly. Anyone know what it is in case I wanted to order a longer one from somewhere?

Thanks!

Tumbler
Old 07-16-2008, 04:40 PM
  #1352  
tim777jet
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Default RE: Bob Cat Copy Falcon 120 Jet

Hi Tumbler, cant measure it as i work away from home, but I replaced my tube with a carbon one. I bought it from Als Hobbies, i asked if it was of similar strength to a boomerang tube and they indicated that it was. They sell lentghs of different diameters off the shelf. I also found that kite manufacturers can supply carbon tube in quite large diameters. I think I posted the details really early on in this thread, cheers Tim
Old 07-17-2008, 02:20 PM
  #1353  
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Default RE: Bob Cat Copy Falcon 120 Jet

hi tumbler,
i did a similar thing to you the other day in a gust of wind, i damaged the main retract and wood damage but luckily my friend came to rescue and has expertly fixed her for me
so thats both mains he has repaired now,thankyou-you know who you are.
be a shame to for you not to repair her,i like mine even if she has some strange quirks
wing tube diameter exactly of mine is 20.21 mm,0.795" and wroughly 51.5 cm,20 1/4"long
rgds mark
Old 07-17-2008, 02:57 PM
  #1354  
new2jets
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Default RE: Bob Cat Copy Falcon 120 Jet

had 4 flights sunday, that supersport can realy push this bird about and vertical is amazing,and 4 spot on landings this plane is so easy to land, sorry to hear about your damage mark, where i was flying we had a dead still day all day long and sunny for a change . iam sure you mate will do a good job for you and have you flying again by the weekend and may give you some landing lessons before you get your eurosport out, saw the pic`s a few pages back she looks good happy & safe landings
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Old 07-17-2008, 03:56 PM
  #1355  
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Default RE: Bob Cat Copy Falcon 120 Jet

Finaly got mine finished

Only need to replace the 4 nylon wing bolts with metal ones.......and then do an engine/fuel system test.
Should have it in the air in 2 weeks time at one of our jet meetings.


Can anyone tell me where the elevator neutral is ?
any picturs maybe ?

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Old 07-18-2008, 08:23 AM
  #1356  
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Default RE: Bob Cat Copy Falcon 120 Jet


ORIGINAL: SJN

Finaly got mine finished

Only need to replace the 4 nylon wing bolts with metal ones.......and then do an engine/fuel system test.
Should have it in the air in 2 weeks time at one of our jet meetings.


Can anyone tell me where the elevator neutral is ?
any picturs maybe ?

SJN,

I found aligning square with the top of the horizontal stab was perfect for me. If not, you will need way too much elevator throw on take-off to rotate off.



Jeff
Old 07-18-2008, 09:40 AM
  #1357  
GreenAcre
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Default RE: Bob Cat Copy Falcon 120 Jet

Where??
Old 07-18-2008, 10:05 AM
  #1358  
tim777jet
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Default RE: Bob Cat Copy Falcon 120 Jet

This has been covered many times, The top of the elevator should be in line with the top of the tailplane profile. The bottom of the elevator will not be in line with the bottom of the tailplane. If looking side on, the elevator will appear to be slightly up. The plane flys fine like this. People have spoken about shimming the booms and altering the angle of thrust line, but just line the top of tailplane and top of elevator and get the beast in the air.
Old 07-18-2008, 11:00 AM
  #1359  
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Default RE: Bob Cat Copy Falcon 120 Jet

Thanks guys. [sm=thumbs_up.gif]

I also found some metal 6mm x 60mm steel bolts for the booms.

I also found a 18mm hardwood stick/rod that fit inside the 20mm wing tube.
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Old 07-18-2008, 11:30 AM
  #1360  
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Default RE: Bob Cat Copy Falcon 120 Jet


ORIGINAL: SJN

Thanks guys. [sm=thumbs_up.gif]

I also found some metal 6mm x 60mm steel bolts for the booms.

I also found a 18mm hardwood stick/rod that fit inside the 20mm wing tube.
Why are you putting a wooden dowel inside the wing tube? Thanks.
Old 07-18-2008, 11:32 AM
  #1361  
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Default RE: Bob Cat Copy Falcon 120 Jet

To strengthen it

My old hotspot also had wood in the wing tube. Included in the kit.
So it cant hurt
Old 07-18-2008, 03:39 PM
  #1362  
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Default RE: Bob Cat Copy Falcon 120 Jet

SJN,

That's a bad spot for the elevator servo, especially if you ever have a hot start. You should add some aluminum tape to protect it. Also if the servo arm is plastic you should replace it with a metal one.

Good luck with the maiden.

Joe
Old 07-18-2008, 09:24 PM
  #1363  
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Default RE: Bob Cat Copy Falcon 120 Jet

" I also found some metal 6mm x 60mm steel bolts for the booms.
"


I don't know if these are readily available in the U.S., however, I will look. Has anyone here taken to changing these blind nuts out to SAE, and does the boom require any additional strengthing at this point ? Seems a little weak at these attachment points ? Thanx.

... zak
Old 07-18-2008, 09:45 PM
  #1364  
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Default RE: Bob Cat Copy Falcon 120 Jet

Some triangle stock and a little hysol isn't a bad idea to reinforce the mount plates. In particular the front plate. Not much holding that one in there.
Old 07-18-2008, 10:03 PM
  #1365  
GreenAcre
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Default RE: Bob Cat Copy Falcon 120 Jet

Where are you guys putting the rudder servos extensions? All the way down the boom? Thats what I thought but when the booms go onto the fuse won't that be an issue? I had a boomerang and that how I routed my extensions for the rudders, down the booms.
Thanks

They DO go through the booms. But where do the rudder extensions connect to? An extension on the top of the wing? YOu guys have any pics??
Old 07-19-2008, 03:23 AM
  #1366  
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Default RE: Bob Cat Copy Falcon 120 Jet


ORIGINAL: SJN

Finaly got mine finished

Wow, SJN. That was one nice interior on that fuse. Is it some sort of pain or something else ?

Regards
Gandalv
Old 07-19-2008, 08:48 AM
  #1367  
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Default RE: Bob Cat Copy Falcon 120 Jet

Thanks Joe.

For hot starts, I was thinking of taking a thin sheet of aluminium, and bend it as an airfoil shape to fit over the stab.
Ill do some testing to see how warm the servo area gets, once I start the engine up in a few days time. Ive seen other pictures further back in this thread with similar setups.


Greenacre, my rudder and elevator extensions are at a connector at the top of the wing.
Here are some pics of my setup.



Gandalv, thanks
It is paint called plati-kote Granit, boght here in a local hardware store. There are several different kinds, with strange textures

http://dk.plasti-kote.co.uk/Product/...51/pccode-3620
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Old 07-19-2008, 12:01 PM
  #1368  
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Default RE: Bob Cat Copy Falcon 120 Jet

I'm probably the last guy in the world to realize that the boom servo pockets aren't going to be deep enough. [] I assume that the simple fix is to block them out from the sides using some hard wood for mounts. Huh ? Yes, no, or maybe ? Got pictures ?

... zak
Old 07-19-2008, 04:56 PM
  #1369  
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Default RE: Bob Cat Copy Falcon 120 Jet

Last time I flew, my keyring LED light fell apart. For fun I removed the LED and taped it to the lower fuse, and dropped the batteries inside the fuse. When I flew the model a lot of people commented on how good it looked during taxi, take off and landing. In flight the light could only be seen when directly coming towards me, but did look great.
I was in an electronics store in Paris and they had on display, a range of ultra bright LEDs, that had a fish bowl lens on the front. They ranged from 1 watt to 6 watts in power at 6 volts. I bought a 6 watt unit that came with a heat sink, it was expensive at around 25 euro with heat sink, but incredibly bright. I have cut the heat sink down and attached the LED to it, this being secured with one bolt through the front retract body. I had some heat conductive glue, but it had gone off, then found that Maplins sell heat transfereing double sided tape. Not quite as efficient as glue, but should be ok. I have fitted 3 x 1.5 volt AAA bats to power the light. At 4.5 volts this is still incredibly bright, but hopefuly wont generate as much heat as the full 6 volts. I didnt manage to fly the model prior to leaving for work, but hopefully in 1 weeks time might be able to try it out. In bright sunlight, the model can be turned to almost 90 degrees and light is still visible. If the nose leg folds up for any reason on landing, with the mains down, there should be just enough clearance from the ground to prevent damage. No resistor is require to operate the LED and it will run quite well on just 3 volts.
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Old 07-19-2008, 05:49 PM
  #1370  
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Default RE: Bob Cat Copy Falcon 120 Jet

the boom servo pockets aren't going to be deep enough.
Zak,

I just made some simple plywood spacers. I also made the cutouts larger to accommodate a full sized servo. If you do enlarge the servo cutouts made sure that you reinforce them on the inside.

Joe
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Old 07-19-2008, 10:35 PM
  #1371  
Ed
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Default RE: Bob Cat Copy Falcon 120 Jet


ORIGINAL: joeflyer

the boom servo pockets aren't going to be deep enough.
Zak,

I just made some simple plywood spacers. I also made the cutouts larger to accommodate a full sized servo. If you do enlarge the servo cutouts made sure that you reinforce them on the inside.

Joe
Thanks for the pic Joe, that was exactly what I needed to confirm my next step. And yes, I also needed to enlarge the pockets in the booms, for both Micro and Standard size. Read the entire thread, and I followed your lead, and am using standard size, but 80 oz's on each rudder. Got two Micro metal gear digitals on elevator. The wood surrounding the pockets seems pretty thick. Not sure what you mean by reinforceing them, length or width ?

... zak
Old 07-20-2008, 09:21 AM
  #1372  
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Default RE: Bob Cat Copy Falcon 120 Jet

I made plywood gussets similar to the picture. Make the outer dimensions as big as you can and still fit through the opening. The same type of plywood piece is already there but you will cut through it when you make the opening bigger. Carefully remove what is left of it and epoxy your new one in place.

I also added a couple strips of plywood to help tie the gusset into some ribs in the area. It's somewhat of a pain working through the small opening to reinforce the inside, but necessary. I wouldn't count on the balsa skin being strong enough to mount the servo.
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Old 07-20-2008, 01:48 PM
  #1373  
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Default RE: Bob Cat Copy Falcon 120 Jet

WHAT A PIECE OF JUNK!!

Wow, is all I can say. What a wastes of time and money this thing was. I started when I was 12 and have 19 years of flying and have never been so disappointed in a plane.

Here is what happened. I took off on her 4th flight and cruised around at half throttle the entire time. I had been scared to open her up, so just flew her gently at half throttle doing slow rolls, a loop, and some inverted flight. After 5 minutes the timer went off, so I put in the first notch of throttle. No problems yet. Then I went to full flaps to test out the crow mix I wanted to try on this flight. It didn't feel dialed in right so I went back to half flap. THAT"S WHEN ALL HE BROKE LOOSE! As soon as I went from full flap to half, it pitched up into a wall, the wing tube folded, and blew up the left wing. Remember.....this is all at just above IDLE!! I shut off the motor and it fell like a paper airplane striaght down and luckily did not damange anyof the importat parts.

Lesson learned.....do not put $3-4,000 worth of electronics and trurbine into a cheap knock off airframe!

Tumbler
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Old 07-20-2008, 02:04 PM
  #1374  
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Default RE: Bob Cat Copy Falcon 120 Jet

Bummer......Mayba a dowl in the wing tube would have helped.

Strange it pitched up when retracting the flaps.
Old 07-20-2008, 02:11 PM
  #1375  
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Default RE: Bob Cat Copy Falcon 120 Jet

If the wing is THAT weak that it folded at less than 50mph, I doubt a dowel is going to help all that much, especially higher g's, but who knows. I wouldn't fly it without something stronger that's for sure. I think the wing folding is what caused it to pitch up, but it happened simultaneously so hard to say for sure what happened first.


ORIGINAL: SJN

Bummer......Mayba a dowl in the wing tube would have helped.

Strange it pitched up when retracting the flaps.


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