RE: Bob Cat Copy Falcon 120 Jet
 

Lots of mods as I initially installed a P80 so I beefed it up every where I could reach, plus the lead in the nose to counteract the weight of the porker P80, now I have a JetsMuts 90 Half the weight, but the same power I thought I would see what sort of saving I could get with the alternative wings ect:

Mike

RE: Bob Cat Copy Falcon 120 Jet
 

Sir:
Do you have tanks in stock ?
Capacity ?
Cost ?
Will they fit in a stock Falcon that I want to build ?
Also, struts ?

Dave

RE: Bob Cat Copy Falcon 120 Jet
 

Mine is 13.5 lbs dry and still going great after about 50-60 flights. With the little PST600, I had to put some lead in the tail booms to get it to balace properly.:D

RE: Bob Cat Copy Falcon 120 Jet
 

Incident report on Falcon 120 w/ p60 yesterday at a Michigan meet. need opinions on cause. Normal take-off. upwind and several hundred feet high suddenly shot up at 45-60 deg angle, totally abnormal situation, cut back throttle, goes into a spin, power recover, drastic climb again, try to sort things out get out about 1/2 mile still trying to get reasonable control, back over field(no range or radio problem on 2.4G), decide to do landing, head down-wind,cut back on power about 50%, spins to starboard wing and crashes.
Checked trans. to see if I had put down flaps and had not.Crash result:rt. side wing destroyed except flap and aileron intact and no problems apparent. Front spar severly bent,main spar(filled with hardwood dowel) still straight as normal.
Left wing totally intact and re-useable EXCEPT aileron push-rod arm
screw is almost out and aileron is not functional.
How can this cause such behavior????????????????????
This was about the 15th flight on the Falcon and it was a *****-cat with the p60. Did my usual pre flight and range check but did not check servo screws.
Lesson: fill the spars with wooden dowels(tight fitting)& chk. servo screws also as part of pre-flight. Dave

RE: Bob Cat Copy Falcon 120 Jet
 

Hi david, sorry to hear of your incident,
did you have 2 servos on the elevator or one.
Have you had any Binding issues with your transmitter and receiver in the past.
What are your failsafe settings, throttle idle, or off, controls all neutral?

With positive uncommanded control commands like you describe, i would look at the radio gear. One area overlooked sometimes are the electrical connections at the servo leads. (they take a bashing and all mine are crimped and soldered now) Have you checked all your plugs to ensure that not one stray wire strand is exposed and could touch an adjacent pin . This has happened to me once and gave me a right wing down command, i was lucky to find it, if i hadnt i would have binned the whole radio set. with radio powered up, disturb ever plug and see if you get a lockout or uncommanded input

How are your batteries in the receiver and the transmitter, have you fitted a new fuel pump or anything that could induce EMI interference to the radio.
Cheers tim

RE: Bob Cat Copy Falcon 120 Jet
 

Tim-
Thanks for fast reply. I did not have any failure to communicate with the Falcon. It responded to all of my commands. I did have double servos on the elevator. Never any binding issues with radio. Double a123 packs on rec. (no switches) and servos with fresh charge. I suspect either the aileron disconnect on the port wing or possibly a boom failure was causing the sudden attitude change(45* pitch-up on full throttle,stall and spin on low). Can a single aileron disconnect cause such symptoms??????? I was wondering if any one had a structural failure that resulted in these symptoms. No evidence of failure is present in the wreckage. All pieces were present at the crash site.
My next one will have glassed wings and will be a single unit as I can transport it with-out dissassembly.
Fail-safe was set to neutral and idle with cut-off per JetCat specs. A real puzzle.
Cheers,
Dave

RE: Bob Cat Copy Falcon 120 Jet
 

I think that an aileron clevis failure would not do this. The aileron would simply weather vane and cause a slight trim change: noticeable but nothing you could not easily overcome. That is unless it fluttered. Hinge failure on the aileron could concievably cause some wild flight anomalies, depending on how it moved/jammed. But a 45 deg pitch-up would not likely be an aileron. Was it a symmetric pitch-up? Or rolling hard while pitching?

Sorry this happened.

RE: Bob Cat Copy Falcon 120 Jet
 

Just a thought but the pitching up makes me wonder about the servos on the elevator. Cant remember if it was this thread a few days ago but in the last week I read somewhere about servo arms coming loose by either cracking or stripping the teeth. Being that it happened the way you described I think thats where I might start. Sorry to hear about this. Its one thing to dumb thumb but really sucks when its hard to explain.

RE: Bob Cat Copy Falcon 120 Jet
 

Guys, I was just in my workshop preparing my jets for a big local jet fly at the end of this month, and noticed that my single elevator servo on my Falcon was moving alot slower going up than down. I put a lipo on top off the elevater and to my horror, after a few more movements, the servo got stuck in the full UP position!! It was a quality 10kg Hitec that I bought when I built my Falcon. I have now replaced it with a Spectrum 10kg digital metal geared servo, but can't help that think that I have just narrowly missed certain disaster![X(]

RE: Bob Cat Copy Falcon 120 Jet
 

Good catch Aussie1, if that had happened in the air it would have been another unexplained crash of a Falcon, blamed on all sort of anomalous things.

One once of maintenance is worth one ton of retrospect.

Mike

RE: Bob Cat Copy Falcon 120 Jet
 

yes it was my post about the servo arm crack at the splined hub, but with 2 servos on the elevator, it is unlikely that 2 failed at the same time, but one could have failed many flights before and the other took the load on its own for this flight
. David, have you got nylon servo arms and are they ok, no hair line cracks.
_ After reccovery, did you get normal control back. If during the climb you pushed the nose down to level off, and lets say one servo arm was bad for a while, the other has just gone, then a large down load might allow the arm to jump one spline. NOw when you release the down elevator the elevator would be one spline UP giving a large pitch up movement as the elevator neutral is way off now. During the fight to recovery from the spin, with large loads on the elevator might allow the splines to realign in the correct position. All this is speculation, but please check your servo arms and even try forcing them in either direction to see if the arms jump. Mine did, but only in one direction, not the other, worth a look. cheers tim

RE: Bob Cat Copy Falcon 120 Jet
 

Or the boom fixings pulled out on one side, or the tailplane pulled out one side, or both may have pulled out both sides, we will never know unless someone has film of the incident and it can be watched in slow motion.

Mike

RE: Bob Cat Copy Falcon 120 Jet
 

Thanks for input guys. Checked some of your ideas today. Port wing was intact and no evidence of aileron failure. Stab was intact-no damage to servos (hitec 5245 digitals) ,servo arms were metal,push-rods were 4-40 with metal clevices, elevator links were plastic on 4-40 arms and no damage to any or disconnects. did not use any of the hardware in kit. All flight control surfaces on both wings were solid after the crash .
The pitch-up was not a rolling maneuver, it was pretty much straight ahead. My best guess is that with port aileron disconnected (screw partly out????) it caused a vibration that partially broke loose the port boom and caused the problems I mentioned. The port wing, both booms and the stab are reuseable after some repair. Fortunately I ordered another Falcon last week and it arrived 2 days prior to this incident. So lets try again!!!!!! It was a great flyer for 14 flights.
Thanks, again.
Dave

RE: Bob Cat Copy Falcon 120 Jet
 

Has anyone got a spare or broken canopy that they would like to sell. I have looked every where and can not find one anywhere the opening on mine is 13 in (333mm) long x 3  1/4 (80mm) in the centre wide and I do have an 8mm lip all the way round.

RE: Bob Cat Copy Falcon 120 Jet
 

I've got the original one from my kit you can have, you pay the postage. PM me if intersted,

Dave

RE: Bob Cat Copy Falcon 120 Jet
 

Check with NORAY for a high quality replasement.
[email protected]

RE: Bob Cat Copy Falcon 120 Jet
 

Guys, I was clearing files from my laptop and found this excellent PDF on a highly modified Falcon. I hope the original poster doesn't mind me posting it again as it has lot's of good imfo for new Falcon builders.

RE: Bob Cat Copy Falcon 120 Jet
 

I was not able to get the PDF file to open. :(

RE: Bob Cat Copy Falcon 120 Jet
 

Grodus, not sure why it didnt open for ya. It worked for me. It was also listed way back, someone might chime in to the post number that it was posted in.




Another thing I found aluminum bolts to replace the nylon bolts with. Got them from Pro Bolt, a bicycle/motorcycle outfit. They have a number of different bolt designs, 2 of which would work for this plane. The Allen Heads were about $1.50 each and the others were $3+ each. I ordered the Allens yesterday and figured I could put washers under the heads and be fine.

RE: Bob Cat Copy Falcon 120 Jet
 

Grodus, maybe your virus checker is blocking it?

RE: Bob Cat Copy Falcon 120 Jet
 

Yep.... it opened for me too.

Looks like they did A LOT of work to beef it up. But, I don't like that it's all one piece. Makes it too hard to transport.

RE: Bob Cat Copy Falcon 120 Jet
 

Aussie1:
Thanks for the file. I opened it and the guy really did a wonderful job. Gave me some ideas for my next Falcon.

On a related note, I need to see if anyone can help me. I have been flying one of the Nitro Plane Falcon 120's as a Dynamax powered edf. This past weekend I had a midair with a small electric plane. The wings, tail and booms are damaged but repairable however, the fuse is a write off. I need to see if anyone has a new or used Falcon 120 fuse (don't care about color) that they are willing to sell. I will take a used/damaged fuse as long as it is repairable. I have posted in the classified but it was suggested that I also post here.

Thanks,
Ed

RE: Bob Cat Copy Falcon 120 Jet
 

Generalhobby.com has for sale new Falcons for $169 - 179 +about $50 shipping. I just bought one about 2 weeks ago and looks ok.

Dave

RE: Bob Cat Copy Falcon 120 Jet
 

Does anyone else have light-up problems??

I find that my gas-start Wren in my Falcon is often a bit reluctant to start, but an identical engine in my Gripen lights on gas straight away.  The only difference is the engine orientation.

Does anyone else with a gas-start engine in a Falcon have problems with light-up? and if so is the engine mounted with the plug accessible near the top?

Has anyone had to mount their turbine with the plug below the mount to get a reliable start?

RE: Bob Cat Copy Falcon 120 Jet
 

Hi all.
About to start a build on this bird so I am just starting to get all my bits together. I purchased a fuell cell from Jet-tech wich holds 90oz.
Has anyone else used this tank on their bird and can they give any feedback as it seems large compared to what others are using, also sits more forward than most I have seen. Wandering what affect it will have on cg and set up.  Thanks.:eek: