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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)

BaldEagel 10-09-2013 02:47 AM

Quote:

Originally Posted by Jeremy_D (Post 11628996)
Hi Col,

I opened up the wheel wells and then put some G10 board (1mm) around the opening and then covered it with film.

See you have been keeping up with your reading, see Page 93 post 2318. LOL

MIke

Jeremy_D 10-09-2013 12:40 PM

Lol! Actually I didn't read this thread before I built mine, would have helped as I scradtched my head for a few days as to what would be the best method for the cutout area ;)

BaldEagel 10-09-2013 02:01 PM

In that case great minds and all that...........

On the latest generation I have modified the rigging to be from above for both the booms and the wings.

Mike

ravikoth 10-12-2013 12:04 AM

Hello Seahawk,
I see that you have the Kingtech K80, i have the same engine & am wondering as to what have you used for Fuel tank, and what size.
Thanks in advance for all input.
Cheers
Ravi


Quote:

Originally Posted by SeaHawk (Post 11628976)
Hello Jeremy,

I have been hammering the poor old Falcon Ver 1 pretty hard since Jan this year. The new K80 now has 7 hrs 51 minutes on it. All in the Falcon. I usually run 7 minute flights and land with fuel for another 4 minutes or so. I am about to start my second Ver 1 Falcon and am looking at KMRC struts. Do you have any pics you can show me please? The struts on the current Falcon are trailing link nose gear struts from HobbyKing.

http://www.rcuniverse.com/forum/atta...mentid=1926465

Much to the horror of the purists I run mostly HobbyKing gear in my current Falcon. The servos were hooked up to a servo tester and cycled at 1 cycle per second for 4 hrs before fitting to the model. :) The electric retracts were cycled for 30 mins. So far all good. Servos are Corona digital metal gear servos and all have passed the cycle test. The only problem I have had with the Falcon is when it lost a fight with a fence post while taxii'ing.

http://www.rcuniverse.com/forum/atta...mentid=1926466

A pair of Version 2 wings from Ken were fitted and the Falcon continues to fly.

uTube video at http://www.youtube.com/watch?v=jrBdMA2Iq5Y

Cheers

Col


SeaHawk 10-12-2013 12:21 AM

Quote:

Originally Posted by ravikoth (Post 11636777)
Hello Seahawk,
I see that you have the Kingtech K80, i have the same engine & am wondering as to what have you used for Fuel tank, and what size.
Thanks in advance for all input.
Cheers
Ravi

Hello Ravi,

I use a 2 litre cooking oil bottle I pinched from the wife and emptied into a sausepan. :)
I also use a 300CC Sullivan tank as an air trap so I suppose I have a useable capacity of 2150CC.
I set my alarm for 7.5 minutes from startup and usually land as the alarm is sounding.
After the flight I have about a fuel level of about 12mm (1/2") remaining in the main tank

I have emptied the tank once after another model crashed on the strip as I was waiting to land. After landing the engine quit as I was taxiing back. The timer read 11mins.
I hope this info is useful. :)

Cheers

Col

ravikoth 10-12-2013 12:37 AM

Hello Col,

Thanks, so much for that bit of info. I am planning to use a 2litre Juice Bottle based on your setup.
Should give me enough time in the air.
Cheers
Ravi

SeaHawk 10-12-2013 02:49 AM

Any pictures of your model available Ravi?

Col

ravikoth 10-12-2013 02:52 AM

sure are, but yet in build, will post them here, went overboard on a lot of things,
sheeted the wings, extended the wing tubes to accommodate ribs deeper into the wings.
porker but at least will not come apart in flight.

SeaHawk 10-12-2013 03:06 AM

2 Attachment(s)
I am about to start my second Falcon 1.20 Ver 1 build. I stripped the film from one wing in preparation for sheeting and found the following.

http://www.rcuniverse.com/forum/atta...mentid=1929193

The second rib in from the tip was a stick of balsa glued in with packing to support the cap strip. One cap strip was missing as well.

http://www.rcuniverse.com/forum/atta...mentid=1929194

This one takes the cake,,, The drawstring provided to pull the aileron lead through to the wing root took a turn around a rib under the covering. Would have been rather frustrating.
This must be a Monday or a Friday built wing. :)

I shudder to think what I will discover when I pull the film off the other wing and the tail surfaces.

Col

mikes68charger 10-31-2013 07:51 PM

Hey guys I'm building mine with an old AMT180. I have read a lost but it's been a bit much. It turns out my falcon has the wings with only one bolt holding it to the fuse. Dose that mean my wings are weaker than the newest ones ?

SeaHawk 10-31-2013 08:18 PM

Quote:

Originally Posted by mikes68charger (Post 11651802)
Hey guys I'm building mine with an old AMT180. I have read a lost but it's been a bit much. It turns out my falcon has the wings with only one bolt holding it to the fuse. Dose that mean my wings are weaker than the newest ones ?

Not necessarily and also yes. :)
The yes is to suggest that it might be weaker than the wings with two bolts but how do we find out? My Version 1 wings were not fully sheeted but it took an argument with a fencepost to wreck that one. My version 2 wings (bought to replace the first ones) are fully sheeted but have only one bolt per side and they seem plenty strong. I am currently building my second Falcon and it is also a version 1, same as the first one. I am going to fully sheet the wing but am staying with the one wing bolt.

Having said all of the preceding I will admit that I generally fly at 1/2 throttle or below and only use full throttle on takeoff and vertical manouvres.

I would suggest that they will be plenty strong as long as you are not flying flat out and pulling pylon turns.

Col

kmrcjets 10-31-2013 09:30 PM

hi it's a good idea to put the wing bolts in the front of the wing it will stop the wing moving
I have had V1 falcons through to V3 carbons. putting the extra bolts is dead easy. line the
wing up and drill the holes from inside the fuselage. a blind nut inside of the front of the
wing and your done
ken
kmrc jets oz

SeaHawk 10-31-2013 11:25 PM

4 Attachment(s)
Quote:

Originally Posted by BaldEagel (Post 11634510)
See you have been keeping up with your reading, see Page 93 post 2318. LOL

MIke

Hello Mike,

I have to admit I hadn't seen your post either before deciding what needed to be done. :)
I was influenced by trial and error. First flight was on unmodified wings, Robart retracts and home built straight "oleos".
First landing was smooth yet during the rollout one of the retracts just fell out. Glued back in and added glue to the other side. They came out again when the RAM 750 shed a blade after takeoff and I had to land in the rough. One leg wasn't fast enough to tuck away and out it came. Next I took both wings to a friend's workshop and did them properly. I bought at great expense (about 12 each) three trailing arm nosegear struts from Hobbyking. I then removed the old U/C bearers and threw them away. New bearers were fabricated from Tasmanian Oak and fitted into the wings with a forward angle to allow the wheel to still retract into the original well. the lot was reinforced with 1/4 square Tassie Oak and covered over with 2.7mm ply. The ply stands a bit proud of the surrounding balsa skin but can be sanded back.

When the version 2 wings arrived from Ken at KMRC Jets I went straight around to Patrick's workshop and we performed the mods before even fitting out the wings. These have survived many flights and some less than perfect landings.

With the new Falcon now being assembled (in Royal Navy'ish colours) We are performing the mods on these wings. I will attach some pics.

http://www.rcuniverse.com/forum/atta...mentid=1935556 http://www.rcuniverse.com/forum/atta...mentid=1935557

http://www.rcuniverse.com/forum/atta...mentid=1935558 http://www.rcuniverse.com/forum/atta...mentid=1935559

The moral to this story is to read this forum and take the advice of the posters BEFORE going out and learning the hard way.
:)

Col

mikes68charger 11-01-2013 04:51 AM

So I have read a lot about strengthening up the retract mounts but what are some things you guys do once inside the wing for the rest of the wing?

I read the alummun wing tube is a few inch short so my plan is to find a wood dowl to fit inside that is 4in short on each side. Then get a wood dowl that is the same size as the tube. Then I only have to shave down 4in of of the dowl so I can extend it a little

Is sheeting the wing and adding some wood to the spar about all needed.

I guess seeing more broken wings would let you know it's weak points

SeaHawk 11-01-2013 05:41 PM

Quote:

Originally Posted by mikes68charger (Post 11651946)
So I have read a lot about strengthening up the retract mounts but what are some things you guys do once inside the wing for the rest of the wing?

After opening up this second lot of wings I would suggest using Robart hinges and adding extra material to the false trailing edge for them to glue into. If you are changing the colour then remove the film from the ailerons and strengthen behind the aileron leading edge where the Robart hinges are located. I am not fully sheeting the ailerons.
Follow Ken's advice for drilling and attaching the wings with two sets of wing bolts.

Quote:

I read the alummun wing tube is a few inch short so my plan is to find a wood dowl to fit inside that is 4in short on each side. Then get a wood dowl that is the same size as the tube. Then I only have to shave down 4in of of the dowl so I can extend it a little
I didn't use the supplied Aluminium (Aluminum in the US) wing spars. My Falcons are both ver 1 that come with 1mm wall thickness tube. (and yes, too short) Friend Brian took me over to a local supplier and we got a length of 2.5mm wall ali tube of the correct diameter. This was then cut to the correct length for each of our Falcons. I used the smaller front spar as supplied.

Quote:

Is sheeting the wing and adding some wood to the spar about all needed.

I guess seeing more broken wings would let you know it's weak points
If you are going to be stressing the model there are probably other areas than could be reinforced but the way I fly this has been adequate (touch wood).
I will be adding epoxy to the boom in the area of the attachment points but that is about all the extra work I will be doing. If you would like pics of certain areas just let me know and I'll take some before closing up the wings.

Col

mikes68charger 11-01-2013 06:27 PM

Wow. I took the time and measured my stock tube and there is only 7 1/4 in of tube that sticks out per side. And it is 7 1/2-7 3/4 to reach the 3rd stringer. And there is play in lengh. As if you push the tube all the way in on one wing it will be a little over a 1in short on one side. Bad bad bad

SeaHawk 11-01-2013 09:10 PM

Buy a length of heavy wall aluminum tube and cut a new one to the right length Mike. Easiest and best way to do it.

Col

Dr Honda 11-02-2013 03:58 AM

Quote:

Originally Posted by SeaHawk (Post 11652577)
Buy a length of heavy wall aluminum tube and cut a new one to the right length Mike. Easiest and best way to do it.

Col


It's metric, and in the USA it's hard to find.

Mike... I've been flying mine for 3 years with a short tube. I just center it, and then put the wings on. BUT... I have thought about epoxy'ing in wood plugs on either end just to help support, and keep it centered.

With that said... I don't have retracts in my Falcon. Since it was my "Trainer" jet... I figure I needed to be able to have some hard landings, so I installed fixed gear on the fuse.

jetflyr 11-02-2013 07:55 AM

[QUOTE=Dr Honda;11652660]It's metric, and in the USA it's hard to find.


Not really that hard to find ... IF you know where to look.
RCFoam in Colorado Springs, CO (yup, the heart of the USA) has a huge selection of metric carbon fiber tubes. Found at: www.rcfoam.com
So, the strongest solution is to purchase the correct diameter tubes, then put a hardwood dowel (from Lowes or Home Depot) in it at the CORRECT length. VERY strong (don't ask!) and inexpensive.
Greg

mikes68charger 11-02-2013 11:17 AM

Well I just picks up a nice hardwood round dowl. I'm going to make the wood go past the stock alum bar 1in on each side. Now I just got to figure out how rap the dowl to the alum diam

I was thinking of eather just fiberglassing it

SeaHawk 11-04-2013 09:19 PM

Quote:

Originally Posted by Dr Honda (Post 11652660)
It's metric, and in the USA it's hard to find.

You could always find a nice friendly SeaHawk in a country where it is easily found and ask for a piece to be mailed over. :)


Col

SeaHawk 11-04-2013 09:49 PM

U/C mount Mod
 
16 Attachment(s)
Hello all,

For what it is worth I have taken pics during the modding of the other wing of my current Falcon build. The wings have been stripped of their film and will be fully sheeted before recovering.
As well as the strengthening of the UC mounts I have raked them forward far enough to allow the use of the 12kg trailing arm nose strut from HobbyKing. These work very well once the springs are upgraded (from the shop they both collapse fully under the weight of my 7.5kg Falcon) So, here goes.

First step was to mark out where the covering is to removed to carry out the mods.

http://www.rcuniverse.com/forum/atta...mentid=1936690 http://www.rcuniverse.com/forum/atta...mentid=1936689

Remove the balsa skin and then remove the old bearers. This is very easy to do by grabbing with pointy nose pliers and wriggling

http://www.rcuniverse.com/forum/atta...mentid=1936691 http://www.rcuniverse.com/forum/atta...mentid=1936695

Cut away the ribs to allow the new bearers to be angled forward. 25mm x 12.5mm (1" x 1/2") bearers extended out to join 4 ribs.

http://www.rcuniverse.com/forum/atta...mentid=1936688 http://www.rcuniverse.com/forum/atta...mentid=1936696

Cut and epoxy gussets to seat new bearers. 6mm (1/4") hardwood.

http://www.rcuniverse.com/forum/atta...mentid=1936700 http://www.rcuniverse.com/forum/atta...mentid=1936699

Epoxy in the new bearers and when dry, cut and epoxy vertical gussets.

http://www.rcuniverse.com/forum/atta...mentid=1936701 http://www.rcuniverse.com/forum/atta...mentid=1936702

We modified the removed balsa skins to make up a set of templates to use when fabricating new ply skins.
Epoxy the ply back into place.

http://www.rcuniverse.com/forum/atta...mentid=1936704 http://www.rcuniverse.com/forum/atta...mentid=1936703

That is it. I will do the final trimming of the cutouts when the gear is fitted.

http://www.rcuniverse.com/forum/atta...mentid=1936705

This is the third set of wings done this way and none have had a retract torn out once modified this way. If you are using straight struts instead of trailing arm then omit the raking forward on the UC bearers.

I hope this has been of some use.
Thanks for the use of your workshop and tools Patrick.

Col

SeaHawk 11-17-2013 08:08 PM

After 76 flights and 9.5hrs of flying time my Falcon's canopy flew off and was lost in the model-eating swamp at the bottom of the field. I have sent off an email to Noray to see if he still has heavy duty replacements available.
Has anybody else had a canopy fly off in flight?

Cheers

Col

jetflyr 11-17-2013 09:36 PM

Quote:

Originally Posted by SeaHawk (Post 11665041)
After 76 flights and 9.5hrs of flying time my Falcon's canopy flew off and was lost in the model-eating swamp at the bottom of the field. I have sent off an email to Noray to see if he still has heavy duty replacements available.
Has anybody else had a canopy fly off in flight?

Cheers

Col

Unfortunately, Ray passed away over the summer....... I do believe that "Modellbau-UK" has sourced molds for tehm though.
Greg

kmrcjets 11-17-2013 10:45 PM

hi col we nearly have a canopy mould ready give me a call
ken kmrc jets
0408998689


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