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-   -   Bob Cat Copy Falcon 120 Jet (http://www.rcuniverse.com/forum/rc-jets-120/5913492-bob-cat-copy-falcon-120-jet.html)

bigplumbs 07-26-2007 03:57 PM

RE: Bob Cat Copy Falcon 120 Jet
 
As you are using Two for each I reacon any servo with 4 - 5 KG torque will do

Dennis

BiGToP 07-26-2007 04:32 PM

RE: Bob Cat Copy Falcon 120 Jet
 
Cheers Den;)

i3dm 07-26-2007 05:05 PM

RE: Bob Cat Copy Falcon 120 Jet
 
TURBOMC, that setup should very quite powerful, it flys the cermrk turbine F16 like a bat out of hell - something definitely sounds strange ?

TURBOMC 07-26-2007 06:08 PM

RE: Bob Cat Copy Falcon 120 Jet
 
I3DM,
Like I said I haven't tried everything yet that can be done to make it better but there are two things I'd point out. 1) the Cermark F16 is about 3 lbs lighter and from what I see it has a thrust tube or nozzle as some call it. I'm flying my fan just as it comes out of the box with no thrust tube. BVM's Viofan necks the 5" ducted fan shrouding down to 3.5" so maybe this increase in thrust pressure at the cost of thrust area is the ticket. What is the diameter of the thrust tube exit on the Cermark F16?

gooseF22 07-27-2007 12:41 AM

RE: Bob Cat Copy Falcon 120 Jet
 
So in preparation to saving up money for a turbine motor, I have a GMS 1.20. I saw the post. What prop do you recommend to flyi it safely until the turbine install? Or is it just too wimpy to be safe? I fly off grass sometimes.

If I use it, what angle on the motor do you recommend for stable pitch?


I want a good all around jet trainer and like the idea of a bigger plane than the kee kat that has flaps. Im going to be building a scale jet next spring.

thanks guys, keep charging ahead!!!
g

i3dm 07-27-2007 06:43 AM

RE: Bob Cat Copy Falcon 120 Jet
 
TURBOMC, the Cermark F-16 does not come with a thrust tube since its built for a turbine, it comes with a metal tail pipe, which was obviously NOT what the guys used in the convertions.

I believe Robert Wagoner from EJF (www.ejf.com) can help you since he has done a few of these convertions of the F-16's and AMD Hawks and such, so he would probably be able to provide you with all the info aobut this fan system \ thrust tubes etc. it is definitely worth it to give him a call !!

av8or48 07-27-2007 07:14 PM

RE: Bob Cat Copy Falcon 120 Jet
 
I'm ready to put a jj1400 on this airframe , let's dedicate some time on what is a MUST reinforcing/change of the structure of this plane to make it work with a turbine.
All you guys that already went through the process to convert the falcon 120 for turbine use, please advise.

jitendra.gurjar 07-28-2007 12:01 AM

RE: Bob Cat Copy Falcon 120 Jet
 
hi tere
i have just signed in as a member .how do i talk to jonny isaiah woods if i have to ? can u send me a mail on how to contact him throug the forum ,on my mail id or alternatively my new mail id ,that is jitendra.gurjar@aol.inn

jitendra.gurjar 07-28-2007 12:03 AM

RE: Bob Cat Copy Falcon 120 Jet
 
sorry thats jitendra.gurjar@aol.in

wingart 07-28-2007 04:32 AM

RE: Bob Cat Copy Falcon 120 Jet
 
Hi av8or48
In reply too your reinforcing question.
I built up fillits of epoxy resin around the underarridge mounts,where the glue was a bit sparse
Next i did the same to the boom mounting plates that hold the captive nuts too mount the boom.
I then used thin cyno too stiffen up the wood around the bolt holes in the main wing panels ,and the tailplane mountig area in the fins.
The boom mounting bolts were discarded and are replaced with m6 metric roofing bolts.
These bolts have nice big flat screw heads for spreading the load and work well.
I replaced all the push rod and clevis ends with 3mm rods and ends.
the control surface hinges were replaced with kavan flat pin hinges which were cross scored and epoxied in place.
So far all is well and no control flutter.
The wheels in thhe kit wre replaced with Durobo of the correct size but this was my perssonal choice.
thr fuzz formers were glued in correctley on my model but may need a little glue in places on others.
Kind regards and good luck with your project Steve Hart

MattyC-130 07-28-2007 08:11 AM

RE: Bob Cat Copy Falcon 120 Jet
 
My Mods so far for JJ1400:
- tail booms mounting plates reinforced with triangle stock and 6-32 cap bolts and blind nuts.
- Inside tail booms inside outer skin where horz stab mounts to boom filled in with balsa to create flat surface and then 1/32 carbon fiber plate epoxied inside against inner wall.
- carbon fiber reinforced mounting plates made on bottom of horz stab for 2 FMA Dig MG servos
- fuz formers shaved and ply plates added in front and behind servo try for mounting all turbine/radio components
- under front plate 3 air tanks 2 for brakes one for starting gas (retract tank in supplied location)
- Nose gear will retract forward
- 64 oz apple juice container and 4 oz UAT for fuel
Servos:
Elevator 2 FMA Dig MG( can match and reverse without match box)
Rudders 2 FMA Dig
Ailerons/Flaps Tower Hobbies Dig HT MG
I run Polk Radio system and got a FMA FS8 receiver. Its awesome has a built in fail safe and will even tell you battery pack voltage
2 2000 Lipos one for receiver and one for starter/pump. (receiver switch fail safe with 6.0v regulator)

Other mods yet to be complete
- all 4-40 hardware with carbon fiber rods
- pinned hinges on all control surfaces
- strengthen main landing gear mounts
- will add nylon wing bolts to front of each wing and also drill and tap wing tubes for sheet metal screws
Matty

BuschBarber 07-28-2007 06:47 PM

RE: Bob Cat Copy Falcon 120 Jet
 
Did you use Robart hinges or did you go with Dubro 1/4 scale flat hinges with the cotter pin? I don't trust CA hinges on a jet.
do you have a link to Euro Oleo struts?
What are the Wheel and Brake sizes and what size wire struts? What are the strut lengths?
Thanks!!!

Jet Lag 07-28-2007 08:21 PM

RE: Bob Cat Copy Falcon 120 Jet
 
All the Boomerangs use the CA hinges and I haven't heard of a failure yet.

BiGToP 07-29-2007 09:28 AM

RE: Bob Cat Copy Falcon 120 Jet
 
Just been looking at the tail sections and I noticed the the servo holes were for mini servo's. Can anyone tell me what servo's do I get to put in these holes, I don't want exspensive ones just the minimum for a Wren 44 gold power plant?
I hear from some experts that the Hi-Tec HS-225MG or HS-225BB which one will be perfect?

bigplumbs 07-29-2007 11:31 AM

RE: Bob Cat Copy Falcon 120 Jet
 
Steve Used HS225MG and he also replaced the wire push rods with 3 mm and better clevises from A1 Models.... I think this is a good Idea and will be doing that as well... About £20 each

Dennis

BiGToP 07-29-2007 12:18 PM

RE: Bob Cat Copy Falcon 120 Jet
 
I've used the same rods but re-enforced them with carbon fibre rod (Dave Wilde tip) So it'll be the HS-225MG's then thanx.


Regards

BiGToP

www.thebigtop.co.uk

bigplumbs 07-29-2007 12:25 PM

RE: Bob Cat Copy Falcon 120 Jet
 
Quote:

ORIGINAL: BiGToP

I've used the same rods but re-enforced them with carbon fibre rod (Dave Wilde tip) So it'll be the HS-225MG's then thanx.


Regards




www.thebigtop.co.uk

Thats interesting what size carbon rod did you use and did it slip over the wires nicely.... This will save a few quid

Dennis

BiGToP 07-29-2007 01:22 PM

RE: Bob Cat Copy Falcon 120 Jet
 
1 Attachment(s)
Dennis

Carbon Rod: 4mm x2mm (4mm OD 2mm ID) and it looks neat too!
Sorry about the focus but you'll get the idea (well done Dave)


Ron

wingart 07-30-2007 01:54 AM

RE: Bob Cat Copy Falcon 120 Jet
 
HI bitop And big plumbs
I changed the push rods to 3mm and the clevises because the clevisis supplied kept breaking after they had been opend acouple of times when making adjustments.
I didnt think they are strong enought.
Dont spoil the ship for a halfpence of tar as the old saying goes.
Regards Steve

BiGToP 07-30-2007 04:43 PM

RE: Bob Cat Copy Falcon 120 Jet
 
Turns out the the servo I was using for the aileron was faulty, it was one out of another plane that I stripped. Dave Stephens had a look for me tonight and couldn't beleive his eyes when he saw the servo go more than 180, it was working like a retract servo (it's not) The servo I'm using on the flap is the same servo but works fine! NO WONDER I WAS HAVING TROUBLE!!!

Servo's: HS-5475HB's strange?
[:@]

gooseF22 07-31-2007 01:44 PM

RE: Bob Cat Copy Falcon 120 Jet
 
Can I again if this baby can be safely flown on a GMS 120? Just temporary until I can save for turbine?

thx guys.

BiGToP 07-31-2007 03:51 PM

RE: Bob Cat Copy Falcon 120 Jet
 
Right....in the plans to the falcon 120/Goldcat 54 it say to set the flaps at 20mm travel. Thats seems like to little to me, Steve or anyone....what have you set yours at?

BiGToP
[:-]

NM_Mark 07-31-2007 08:55 PM

RE: Bob Cat Copy Falcon 120 Jet
 

Quote:

ORIGINAL: gooseF22

Can I again if this baby can be safely flown on a GMS 120? Just temporary until I can save for turbine?

thx guys.
I think post #53 (somewhere around there) spoke of someone who flew it with a GMS 120 - said it was not enough.

Mark

wingart 08-01-2007 04:48 AM

RE: Bob Cat Copy Falcon 120 Jet
 
Hi big top
Have set my flaps up too 45degrees,they work superb at slowing down the falcon, i flew with big plumbs last night no head wind to speak of full flap landing speed approx 20mph.
With flaps deployed a small amount of up elevator is required to keep the nose up.
I use half flap for take off and off grass, take off roll is approx 100yds give or take a few feet.
I use the side slider on my 9 zap for flap control .
Hope this helps regards Steve.

BiGToP 08-01-2007 07:19 AM

RE: Bob Cat Copy Falcon 120 Jet
 
Steve

Yes thanks Steve it's a great help

BiGToP


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