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Bob Cat Copy Falcon 120 Jet

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Old 08-01-2008, 12:38 PM
  #1451
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Default RE: Bob Cat Copy Falcon 120 Jet

Mine weighs in at 14.2 lbs dry, I carry about 68 oz of fuel. You can fly it straight up out of sight. I have been flying turbines for about 5 years and have a starfire and had a viper both turbine power. I would say my falcon is as fast as the Viper. I friend also has a falcon with a P80 in it and it is also very fast. George
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Old 08-01-2008, 01:00 PM
  #1452
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Default RE: Bob Cat Copy Falcon 120 Jet

Hi quick question what would be the ideal airfoil profile for this?
Closest i got was a NACA 1410 modified to 1.5% camber (im new to this airfoil codes but its the closest i found to my bobcat .50 wing on profili)
Thanks
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Old 08-01-2008, 01:48 PM
  #1453
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Default RE: Bob Cat Copy Falcon 120 Jet


Quote:
ORIGINAL: aquaskiman

Mine weighs in at 14.2 lbs dry, I carry about 68 oz of fuel. You can fly it straight up out of sight. I have been flying turbines for about 5 years and have a starfire and had a viper both turbine power. I would say my falcon is as fast as the Viper. I friend also has a falcon with a P80 in it and it is also very fast. George
What turbine do you have on it?
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Old 08-01-2008, 01:55 PM
  #1454
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Default RE: Bob Cat Copy Falcon 120 Jet

I was thinking the same thing. Everywhere I flew my Kangaroo with 18lbs thrust, people thought it was really fast, and were shocked to hear best it ever did was 178mph out of a very steep dive. 180-200 is pretty darn fast and not likely to happen with a Falcon.

Here's 178mph.

http://www.youtube.com/watch?v=y_kDRDtAqNY


Quote:
ORIGINAL: noahb

I doubt it is doing 180-200. I have dove mine full power and come out straight and level and was clocked at 168 mph after a 100 or 200 feet. However, anything is possible. The falcon has a thick wing and stab. However, it could be that his engine is putting out more then 14lbs of thrust. Who knows.

I too have the super bee and I have exellent vert. Not on take off, but once up to speed, it will climb very good for awhile. Not unlimited, but very good.
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Old 08-01-2008, 02:01 PM
  #1455
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Default RE: Bob Cat Copy Falcon 120 Jet

my buddies boomer with a WREN SS gets 140mph straight and level at best. Now coming out of a dive, I am sure he is hitting mid 150's.
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Old 08-02-2008, 10:47 AM
  #1456
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Default RE: Bob Cat Copy Falcon 120 Jet

Woketman I have a Wren MK3 14lbs thrust George
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Old 08-02-2008, 11:35 AM
  #1457
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Default RE: Bob Cat Copy Falcon 120 Jet


Quote:
ORIGINAL: aquaskiman

Mine weighs in at 14.2 lbs dry, I carry about 68 oz of fuel. You can fly it straight up out of sight. I have been flying turbines for about 5 years and have a starfire and had a viper both turbine power. I would say my falcon is as fast as the Viper. I friend also has a falcon with a P80 in it and it is also very fast. George
Well then if you have a 14 lb thrust Wren on it and it weighs 14.2 lbs dry and the turbine burns fuel, how can it possibly "fly it straight up out of sight"? Are you claiming unlimited vertical???
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Old 08-02-2008, 03:23 PM
  #1458
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Default RE: Bob Cat Copy Falcon 120 Jet

I am claming that I can fly it stright up out of sight, no I don't think it would make it to the moon. George[sm=48_48.gif]
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Old 08-03-2008, 04:56 PM
  #1459
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Default RE: Bob Cat Copy Falcon 120 Jet

Mine just flew 3 flights.

Fly`s absolutly great
Unfortunatly, my JJ-1400, which was running realy well, threw a turbine blade. [:@]
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Old 08-03-2008, 05:19 PM
  #1460
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Default RE: Bob Cat Copy Falcon 120 Jet

You mean it threw a chunk of a single blade? That is the most benign turbine wheel failure I have ever seen!!! Is that the only damage?
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Old 08-03-2008, 05:26 PM
  #1461
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Default RE: Bob Cat Copy Falcon 120 Jet

Yea...I actualy flew the entire third flight with the blade like that.

There was vibration from idle 45.000 until 50.000 rpm, then it ran smoothe to 160.000. Very strange. But even at full RPM, it had noticable reduced power.
So I landed as soon as i felt something was wrong.
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Old 08-04-2008, 06:47 AM
  #1462
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Default RE: Bob Cat Copy Falcon 120 Jet

Nice looking plane SJN Glad you got it down ok
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Old 08-04-2008, 07:05 AM
  #1463
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Default RE: Bob Cat Copy Falcon 120 Jet

Thanks George.
The plane realy flys well, so it was not realy an event to get it down safely

Ill try and order a new turbine wheel for it, or buy a MW-54 kit or merlin 90.
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Old 08-04-2008, 11:23 AM
  #1464
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Default RE: Bob Cat Copy Falcon 120 Jet


Quote:
ORIGINAL: SJN

Thanks George.
The plane realy flys well, so it was not realy an event to get it down safely

Ill try and order a new turbine wheel for it, or buy a MW-54 kit or merlin 90.

get a supersport and feel the power !!!!!!!!!!!!!!!!!!
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Old 08-04-2008, 11:42 AM
  #1465
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Default RE: Bob Cat Copy Falcon 120 Jet

ahhh...I dont know...
The merlin 90 has more thrust, and is cheaper, and it also comes from a company with a good reputation.

I have ordered a new turbine wheel. The parts in the JJ still look nice, and fit well.
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Old 08-04-2008, 11:53 AM
  #1466
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Default RE: Bob Cat Copy Falcon 120 Jet

Wow! You took all that apart by yourself ? It does look very clean. Good luck finding a wheel. Do you perform the re-balance yourself ?

... zak
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Old 08-04-2008, 12:01 PM
  #1467
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Default RE: Bob Cat Copy Falcon 120 Jet

lol, its not rocket science.
Buying a JJ, makes you wiser

JJ sells the turbine wheel balanced.
I will install it, and see how it runs. Any sign of imbalance, and I know someone who can help me get it re-balanced.
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Old 08-04-2008, 01:30 PM
  #1468
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Default RE: Bob Cat Copy Falcon 120 Jet


Quote:
ORIGINAL: SJN

lol, its not rocket science.
Buying a JJ, makes you wiser

JJ sells the turbine wheel balanced.
I will install it, and see how it runs. Any sign of imbalance, and I know someone who can help me get it re-balanced.

I would throw this turbine engine to the bin, or use it as paperweight. You're risking your life, it just isn't worth it. [sm=thumbs_down.gif]
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Old 08-04-2008, 01:52 PM
  #1469
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Default RE: Bob Cat Copy Falcon 120 Jet

I doubt that you would die if the thing blew up in your face.......might give you a bad acne the rest of your life though
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Old 08-04-2008, 05:09 PM
  #1470
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Default RE: Bob Cat Copy Falcon 120 Jet

I agree with Sonnich. I would not have paid good money for a JJ in the first place, but now that he has it, might as well try to salvage something. And it's fun to mess with it!
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Old 08-04-2008, 06:30 PM
  #1471
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Default RE: Bob Cat Copy Falcon 120 Jet

hah...I found an old picture that I took about a year ago.......you can actualy see the fault lines in the blade where it has cracked!







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Old 08-04-2008, 11:12 PM
  #1472
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Default RE: Bob Cat Copy Falcon 120 Jet

Yes, I can see the fault lines clearly. That's exactly where it broke. The two to the left of it also appear to be nicked.

It is good that you are replacing it.

... zak
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Old 08-05-2008, 12:36 AM
  #1473
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Default RE: Bob Cat Copy Falcon 120 Jet

Well that's kinda unsurprising isn't it?


Just some facts for the numerically inclined:
The roots of the blades experience 250,000G's at top RPM. That turns out to anywhere between 400lbs to over 2000lbs of stress depending on the wheel in question.
The metal is Inconel 718 or 713 and is operated at a temperature close to the theoretical maximum (read - no room for error).
Inconel is hard to work with. It must be vacuum melted and vacuum cast or some of the ingredients will evaporate leaving something that looks like Inconel but is not.
The wheels MUST BE X-RAYED for cracks, bubbles or other defects (remember - no room for error).

Making good wheels turns out to be rather difficult and expensive. If a single wheel in a batch is found to be faulty the entire batch is scrapped.
These engines, though simple in overall design, do require good craftsmanship. This is part of the reason that they are so expensive.


I seriously doubt that JJ x-rays his wheels. I also doubt he handles Inconel properly. I don't doubt that he cuts costs wherever he can.

Just my ranting $0.02
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Old 08-05-2008, 04:52 AM
  #1474
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Default RE: Bob Cat Copy Falcon 120 Jet

How much run time did you have on the JJ??? George
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Old 08-05-2008, 05:10 AM
  #1475
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Default RE: Bob Cat Copy Falcon 120 Jet

5 hours on it, 48 cycles.
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