Bob Cat Copy Falcon 120 Jet
11-18-2010, 03:01 AM
#3851
RE: Bob Cat Copy Falcon 120 Jet
What is trying to be achived is a 0deg turbine thrust line in comparison to the datum line through the fus, for ease of reference we can assume the datum line is the mean average of the incidence of the wing and tailplane, the easiest way is to determine the incidence of the wing and the tailplane and make the thrust line between to two i.e. put the airframe on its wheels for stability whilst carrying out these checks and find the incidence of the wing, lets say its 3 deg positive and then the incidence of the tailplane, lets say its at 5 degs positive to get the turbine at 0degs would require it to be at 4 degs positive sitting on the wheels, conversly if the wing was at 5 degs positive and the tail at 3 degs negative the turbine would need to be at 1 deg positive, I hope that is clear and helps.
Alternativly assemble the airframe and eyeball it from the wing tip.
Mike
Alternativly assemble the airframe and eyeball it from the wing tip.
Mike
11-18-2010, 05:10 AM
#3852
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RE: Bob Cat Copy Falcon 120 Jet
ORIGINAL: BaldEagel
What is trying to be achived is a 0deg turbine thrust line in comparison to the datum line through the fus, for ease of reference we can assume the datum line is the mean average of the incidence of the wing and tailplane, the easiest way is to determine the incidence of the wing and the tailplane and make the thrust line between to two i.e. put the airframe on its wheels for stability whilst carrying out these checks and find the incidence of the wing, lets say its 3 deg positive and then the incidence of the tailplane, lets say its at 5 degs positive to get the turbine at 0degs would require it to be at 4 degs positive sitting on the wheels, conversly if the wing was at 5 degs positive and the tail at 3 degs negative the turbine would need to be at 1 deg positive, I hope that is clear and helps.
Alternativly assemble the airframe and eyeball it from the wing tip.
Mike
What is trying to be achived is a 0deg turbine thrust line in comparison to the datum line through the fus, for ease of reference we can assume the datum line is the mean average of the incidence of the wing and tailplane, the easiest way is to determine the incidence of the wing and the tailplane and make the thrust line between to two i.e. put the airframe on its wheels for stability whilst carrying out these checks and find the incidence of the wing, lets say its 3 deg positive and then the incidence of the tailplane, lets say its at 5 degs positive to get the turbine at 0degs would require it to be at 4 degs positive sitting on the wheels, conversly if the wing was at 5 degs positive and the tail at 3 degs negative the turbine would need to be at 1 deg positive, I hope that is clear and helps.
Alternativly assemble the airframe and eyeball it from the wing tip.
Mike
Man that post made my head hurt. LOL
11-18-2010, 07:43 AM
#3853
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RE: Bob Cat Copy Falcon 120 Jet
ORIGINAL: BaldEagel
Page 97 post 2405 is how I did it, but then I took all the formers out and replaced them with a lattice girder type arrangement.
Mike
Page 97 post 2405 is how I did it, but then I took all the formers out and replaced them with a lattice girder type arrangement.
Mike
Thanks... that looks good, and I can add that quick. I know I have some arrow shaft in the garage.
11-18-2010, 11:28 AM
#3854
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RE: Bob Cat Copy Falcon 120 Jet
Here are some photos of my engine at 0 degrees. You will notice that the bottom of the engine is parallel to the top of cantilever engine tongue. I have noticed that some people are making very substantial engine mounts, but with turbines, there is no vibration or sudden gyroscopic changes that you would see in a piston and prop setup. My mount is 1/16 angle aluminum from the local hardware store, and is more than adequate. You may also notice on the front of the mount, the upper angle does not quite match the front of the mount. That is from when I had the engine at 5 degrees. The aluminum angle bolted on the bottom also does a great job to support the cantilever engine mount tongue.
11-18-2010, 11:36 AM
#3855
RE: Bob Cat Copy Falcon 120 Jet
Its not the engine vibration that we were concerned about, it was the inertia from a not too perfect landing that cracks the fus with the weight of the turbine.
Mike
Mike
11-18-2010, 11:43 AM
#3856
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RE: Bob Cat Copy Falcon 120 Jet
My mounts are beefier than they need to be. I can always machine out the back of them to make the a little thinner.
New question: Brakes:
On the Falcon, is a single nose brake OK, or do I need them on the mains? I know it slows down for the landing... but I figure I would ask what people are doing.
New question: Brakes:
On the Falcon, is a single nose brake OK, or do I need them on the mains? I know it slows down for the landing... but I figure I would ask what people are doing.
11-18-2010, 11:49 AM
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RE: Bob Cat Copy Falcon 120 Jet
Thanks Dave! That made it very clear. And you have no problems flying at 0 degree's?
And you have no problems flying at 0 degree's?
ORIGINAL: f6hlct
Here are some photos of my engine at 0 degrees. You will notice that the bottom of the engine is parallel to the top of cantilever engine tongue. I have noticed that some people are making very substantial engine mounts, but with turbines, there is no vibration or sudden gyroscopic changes that you would see in a piston and prop setup. My mount is 1/16 angle aluminum from the local hardware store, and is more than adequate. You may also notice on the front of the mount, the upper angle does not quite match the front of the mount. That is from when I had the engine at 5 degrees. The aluminum angle bolted on the bottom also does a great job to support the cantilever engine mount tongue.
Here are some photos of my engine at 0 degrees. You will notice that the bottom of the engine is parallel to the top of cantilever engine tongue. I have noticed that some people are making very substantial engine mounts, but with turbines, there is no vibration or sudden gyroscopic changes that you would see in a piston and prop setup. My mount is 1/16 angle aluminum from the local hardware store, and is more than adequate. You may also notice on the front of the mount, the upper angle does not quite match the front of the mount. That is from when I had the engine at 5 degrees. The aluminum angle bolted on the bottom also does a great job to support the cantilever engine mount tongue.
11-18-2010, 11:50 AM
#3858
RE: Bob Cat Copy Falcon 120 Jet
Brakes on the mains, as the air tube will be under a bit more flexing than normal on the front when steering, then again I don't think anyone makes a front wheel brake that works very well.
Mike
Mike
11-18-2010, 01:12 PM
#3859
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RE: Bob Cat Copy Falcon 120 Jet
Here is my programing setup with the engine at 0 degrees. I have gone with all control throws as recommended and use 50% expo on all surfaces. It feels solid in the air and even though I have different flight modes setup, I tend not to use them on this plane as it feels very controllable at all speeds. The throttle to elevator mixing only puts about 2-3mm of down at full throttle, and there is no pitch change in the plane at any throttle settings.
-Throttle to Elevator mix is linear from idle to full.
-Half flap is 15 degrees with slight down elevator.
-Full flap is 45 degrees with more down elevator and about 3mm of up aileron. That is the flaperon mix.
If you are using the JR Data Exchange, I can send you the data file for this model. Just send me a PM.
11-18-2010, 01:30 PM
#3861
RE: Bob Cat Copy Falcon 120 Jet
No wonder you don't need to do much reinforcing on yours, I did not know that JR had an Auto Land function, I think that's cheating. LOL
Mike
Mike
11-20-2010, 02:10 AM
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RE: Bob Cat Copy Falcon 120 Jet
Hi!
I plan to use Yamada YS 120 for this plane with 15/10 3 blade pusher - will it be sufficient?
or it's better to look for 2-stroke - like supertigre 2000-2500?
thank you
I flew bobcat 51 with 46 towerhobbies - it was little underpower
11-20-2010, 03:09 AM
#3863
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RE: Bob Cat Copy Falcon 120 Jet
ORIGINAL: Jetpilot24
Just thought I would share this video of my buddy Garrett and I trying to fly some formation.
Enjoy
Joe
http://www.youtube.com/watch?v=BeBZpdvl1Ik
Just thought I would share this video of my buddy Garrett and I trying to fly some formation.
Enjoy
Joe
http://www.youtube.com/watch?v=BeBZpdvl1Ik
Very good indeed. How did you find the space to get all that smoke oil in her. And do you find you have loads of mess on the tail plane cos of the smoke when you land
Dennis
11-20-2010, 05:03 AM
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RE: Bob Cat Copy Falcon 120 Jet
I'm also very curious to see your smoke oil setup. What size fuel tank are you using with the smoke tank? In fact can you let us know what the capacity of both is?
ORIGINAL: bigplumbs
Very good indeed. How did you find the space to get all that smoke oil in her. And do you find you have loads of mess on the tail plane cos of the smoke when you land
Dennis
ORIGINAL: Jetpilot24
Just thought I would share this video of my buddy Garrett and I trying to fly some formation.
Enjoy
Joe
http://www.youtube.com/watch?v=BeBZpdvl1Ik
Just thought I would share this video of my buddy Garrett and I trying to fly some formation.
Enjoy
Joe
http://www.youtube.com/watch?v=BeBZpdvl1Ik
Very good indeed. How did you find the space to get all that smoke oil in her. And do you find you have loads of mess on the tail plane cos of the smoke when you land
Dennis
11-20-2010, 06:03 AM
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RE: Bob Cat Copy Falcon 120 Jet
ORIGINAL: Sansan
Hi!
Hi!
I plan to use Yamada YS 120 for this plane with 15/10 3 blade pusher - will it be sufficient?
or it's better to look for 2-stroke - like supertigre 2000-2500?
thank you
I flew bobcat 51 with 46 towerhobbies - it was little underpower
Think the ST2000 would be bit big and heavy would a ST90 not suit better
11-20-2010, 06:44 AM
#3866
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RE: Bob Cat Copy Falcon 120 Jet
I understand about sound 
YS has max rpm 12500 and reccomended prop sizes: 14 X 12 to 16 X 10
ST 2000 - 13000 (16" prop suggested) (not sure about power - they are out of production)
st90 is on the way to Moscow for a flycat90 - soon I will checkif it will haveenoughpower
YS has max rpm 12500 and reccomended prop sizes: 14 X 12 to 16 X 10
ST 2000 - 13000 (16" prop suggested) (not sure about power - they are out of production)
st90 is on the way to Moscow for a flycat90 - soon I will checkif it will haveenoughpower
11-20-2010, 06:56 AM
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RE: Bob Cat Copy Falcon 120 Jet
If you already have those engines... I would go ST2000. Yes, it's a little heavy, but from what I've been reading... it could use the weight in the back.
11-20-2010, 07:36 AM
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RE: Bob Cat Copy Falcon 120 Jet
If it can use the weight at the back with a prop setup then ok, the ST2000 are big engines, and the 20cc would be much more powerful that a 120fs the 20cc would be enough but you will need to swing a 16" prop the 25cc uses a 18"
11-20-2010, 11:21 AM
#3869
RE: Bob Cat Copy Falcon 120 Jet
Have you thought about ground clearance with those props, not forgetting the clearance gets less as the airframe rotates prior to lift off with a pusher, Oh yes the FlyCat is a dog, does nice flat spins once it goes dead stick.
Mike
Mike
11-21-2010, 08:23 AM
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RE: Bob Cat Copy Falcon 120 Jet
Hi Guys... I got a fuel tank question.
I made up a 64oz juice bottle tank, but I used Tygon inside for the clunk line. (As I would normally do for gas) But, knowing how fast a turbine drinks fuel... I have concerns about the clunk. The hose seems too stiff to let the clunk move the the front of the tank. (as if I was in a long dive)
What are you guys using for clunk hose? Or do I just need a heavier clunk?
I made up a 64oz juice bottle tank, but I used Tygon inside for the clunk line. (As I would normally do for gas) But, knowing how fast a turbine drinks fuel... I have concerns about the clunk. The hose seems too stiff to let the clunk move the the front of the tank. (as if I was in a long dive)
What are you guys using for clunk hose? Or do I just need a heavier clunk?
11-21-2010, 11:16 AM
#3871
RE: Bob Cat Copy Falcon 120 Jet
I use a heavy Orbit clunk, it has a ceramic filter inside a fabric outer case on Tygon tubing, I don't use a UAT and have not had a problem with this set up.
Mike
Mike
11-21-2010, 11:47 AM
#3872
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RE: Bob Cat Copy Falcon 120 Jet
Even if the clunk does not move forward, it will be OK. If not using a hopper tank (UAT) like Mike, you will want it to move to the front when required. If it cannot go to the front, the fuel supply will momentarily be supplied by the hopper and all will be fine. I usually set up the main tank so that the clunk can go all the way forward, but sometimes I just can't get that to work. That is when you need the hopper.
And Mike, I disagree with you signature line: on the Space Shuttle Main Engines (SSMEs) we run them at 104% rated thrust on ascent. If you have some emergency abort situations, they are rated at 109% for short periods!!!!
And Mike, I disagree with you signature line: on the Space Shuttle Main Engines (SSMEs) we run them at 104% rated thrust on ascent. If you have some emergency abort situations, they are rated at 109% for short periods!!!!
11-26-2010, 12:48 AM
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RE: Bob Cat Copy Falcon 120 Jet
I have a set of Spring Air 302 HD retracts. Does anyone know where i can get a good set of struts to use with them? I'm going to be running a Ram 500X off of a grass runway.
Mitchell
Mitchell