erazz

Sorry guys, not yet... I had a brain freeze and forgot to fill the hopper tank. The resulting propane flame torched my tail. I''m fixing it as we speak... I''ll keep you posted.

tim777jet

Fitted some brakes to the Falon, just some info if you want to make your own. Found some ally wheels in a model shop in France, they were about 1/2 the weight of the off the shelf jet ally wheels. Not sure what they were for (may be even a large rc car) but have split rims and a removable mousse in the tyres.
I made up ally brake drums and machined a grove to except an O ring ( i used and old parting off tool ground to about .002 inch under the width of the o ring and with a flat bottom). The drum and o ring are just under the size of the wheel rim. I use Skymaster air line quick disconnects and i cut off the brass nipples from one of these and use these for the air intake pipe fitting, instead of making them myself. just drill a hole a few thou under the nipple outer diameter and press them in. I drilled a small hole to allow air to the underside of the o ring. When air is fed in the o ring expands and contacts the wheel hub rim and then deforms and seals.
I found the seal was not very good like this, so with a stanley knife i carefully sliced the o ring on the inside, to half of its thickness. What i did find was that the o rings i used, which i purchased from Home Base DIY, in an assortment pack, were actually hollow. These are excellent, as they inflate and seal perfectly against the sides of the o ring channel and provide good braking. I used a Tam jets door operated air selector valve, (£20 from als hobbies), for on off control and have run at 50 to 90 psi, all fine. This valve is a beautiful piece of work and would cost me more to make one.
Excuse the messy install, i managed to fit everything about 3 seconds before leaving the house for the flying field.

Flew on Saturday, wind was horrendace, 90 degrees accross the runway and visious. Decided to take off from a 15 feet section of roungh concrete, just before the grass runway, so took off accross width of runway.
The brakes held with throttle somewhere between3/4 and full. take off was very short.
Landing was interesting but so slow in the strong wind, didnt have time to try the brakes, next time.

During the brake install, i fitted a set of Eurokit retracts, they are reasonable price. They are just a bit to wide to fit betwen the undercarriage mounting rails, so rather than weaken the rails, i machined the sides of the fiber units. This is really easy to machine, you can just hand file them. I cut off approx 10 mm from the alloy strut pin block on the main units. This reduced the the length of my legs by 10mm and the wheels still fitted the wheel wells.This might seam strange but i wanted to increase the angle of attack with the aircraft on the ground, to provide better take off performance. I have my nose gear as long as possible so the wheel just fits in the bay. I think this really helps get the model off the ground quicker, which is very important for grass ops.

Just an update, i purchased some more o rings from Home Base, but have found that they are not hollow, but solid. I must have had rouge ones in my packets. I used the solid ones, and cut them @ 2/3 the way through and they perform the same. I was flying a few days ago in the rain ( good old UK weather), and the grass was really wet. Brakes still held on the wet grass just over 1/2 throttle. On landing the brakes worked better than i expected on the wet grass.
There is a narrow section of tarmac adjacent the grass runway and taxied around, braking was good and model was very controllable, although they are not progressive brakes, just on or off, i am pleased with them.

joeflyer

My Feedback: (48)

Just got back from putting flights #6 & 7 on the Falcon. This time it did something strange, when flying straight and level it would wag its tail back and forth.

Previously I had my Wren SS dialed down to 14# and it flew well. This time I had it bumped up to 16#, so it was moving faster and there was a 10 mph crosswind. So was it the extra speed or the crosswind that made it do that? Perhaps some aero expert can comment. Also what can I do to prevent the wag?

Joe

tim777jet

Hi Joe, i have had this as well, only in strong winds, usually while flying 90 degrees accross the wind. I flew a couple of days ago in really strong winds and encountered some tail wag. flew today with light to moderate wind and had no wag at all. When i have encountered these wags, the model is still controllable, cheers Tim

joeflyer

My Feedback: (48)

Tim,

Sounds just like my experience, it was windy today and I was flying 90 degrees across the wind. The model was controllable, but I landed early because I thought something might be coming loose. Everything checked out OK. I''m wondering if there is a way to fix it.

Joe

falconlover7

where can u get the controller and can you tell me what does not come with this airplane super falcon 120?

littlepiston

My Feedback: (12)

sheesh falconlover7 were to start?[X(] hmmm anyone.........................anyone,,,,,,,,,,... ...ANYONE?

Woketman

My Feedback: (6)

Highly swept wing induced Dutch Roll? A gyro will fix it.

Ken Jack

Re: Bob Cat dance

I might be showing my age , as what you are experiencing was called the quickfly dance, on model designed by Phil Kraft. It had a barn door wing, so has to do with too much fin area or sweep back, both causing high stability in yaw control ( too large a fin ), and only happens at high air speeds.

Ken Jack.

new2jets

hi every one just read this thread. Ive put pic & how i done mine on bigplumbs thread on rc group
page 12 take a look but heres some pics, just upgraded mains to custom made trailing links will post some pic in few days.

http://www.rcgroups.com/forums/showt...=12post9399431

tim777jet

Great install, do you have any down thrust on the engine, hard to see in the pics. Another approach to engine mounting, really niece. With your elevator, is it split, ie one servo each working one half, for redundance purposes, should one servo fail or, just two servos working one complete elevator.
Havnt read your thread yet, but what retracts are you using, cheers tim. ps any inflight video

new2jets

Hi i`ve got 6 degrees down thrust which seems about right, only had one flight so far but she don`t seem to climb or fall by putting power on or off . i used airpower 250 retracts with home made oleos which worked ok but as our main field is grass i made some trailing links, only fitted them tonight so no photos yet but will do some tomorrow and post them, elevator is in one piece with to servos mixed. hopfully will fly at classic jets at abington friday and get some video then.
cheer`s

new2jets

hi just uloading some photos of new custom made undercarrage hopeing these will be ok on grass? photo speak louder than words so here they are.

Woketman

My Feedback: (6)

VERY cool struts, New2!!! Did you machine them out of aluminum?

new2jets

HI yes they are aluminaum with 4 mm roll pins in and bronze bush to pivot on in the main round leg and then painted. will draw them up & post drawings for you machinists out there.

cheers

Woketman

My Feedback: (6)

VERY nice!!!!

tim777jet

Hi Joe, just an update on the tail wag, flew last Sunday, wind was really strong and about 70 degrees off the runway, and strong gusts. In flight had only a couple of occasions where there was a slight wag. Another flyer had a Boomer and in flight his wagged more than the falcon. I then flew a couple of days after, with less wind, but still a stiff breeze, and had couple of gentle wags. flew on Tuesday and this is the calmest weather i have ever had, Falcon flew a dream and no tail wag at all.
I read a report on the Bobcat a while back and they stated that the test model had a gyro fitted to the rudder, presumably for this reason, i dont think i need to go to extra trouble of doing that, doesnt bother me if i have an occassional wag.
On the really windy day on last flight, made a niece landing, but tried to hold the nose off with the elevator, a little to much applied and the falcon proceeded to point its nose skywards, very rapidly, as it was subjected to a hefty gust. Obviously no time to apply throttle due spool up time, managed to get the nose down again, but ran out of up elevator for the flare, due to the really slow airspeed. I damaged my nose gear retract unit, the 4 mm pin pulled down through the fiber sides and the nose leg pushed itself backwards. No other damage. Machined up 2 bushes to take out the elongated pivot pin holes, so flew again following day. Glad this happened or it might have ripped the leg out of the plane. I must say the plane behaved brilliantly at this slow speed, other models i am sure would have dropped a wing and gone in, saved again by a great model. despite the bad weather, i am up to 40 flights now and enjoy it more and more

Forgot to mention, when i fitted the Eurokit retracts, due to the different pivot point positions compared to the original units, i managed to reduce the length of the main gears by 10mm and extended the nose gear by 10mm. This i think contributed to the models willingness to get airbourne after landing, as the wing was at a slightly higher angle of attack, with the wheels on the ground. I have reduced the length of the nose leg by 10mm and now take offs are niece and smooth, dont need to heave the elevator back abrutly to get the nose off the ground, it flys off smoothly and subsequent landings have been smooth and the model sits on the ground better during the landing roll.

Just on a side note, bumped into a guy who organizes a model water plane event at Beale Park every year, near Reading i think junction 12 on M4. It will be on this Sunday 27th April, he is expecting around 25 planes, unfortunately i am working so cant attend.

leelevinson

My Feedback: (37)

Only have to mount the engine on my Falcon.
Using a JJ 1400.
Have noticed two items on this thread:
1 - most people have been setting up the engine with 4 - 5 degrees of down thrust.
2 - the elevator has to be set up a bit (not level with the flat bottom of the horizontal stab).
I am thinking of not using down thrust as this might alleviate the need to offset the elevator.

Anyone installed the engine along the thrust line ??
Will that get the exhaust too close the the stab ??

Thanks

joeflyer

My Feedback: (48)

Tim,

Thanks for the report. I flew again Monday. There was not as much of a cross wind as before and I experienced a gentle tail wag only once during two flights. I agree that at this point it's not anything to worry about and no need to invest in a gyro. I'm up to 10 flights and have my Wren SS set to 16 lbs. After a couple more flights I'll give it the full 18 lbs. and re-evaluate the tail wag.

I'll have to say that this is one of the easiest planes to land, just like a .40 trainer. With full flaps you can land at about 5 mph. I did catch a gust of wind on one landing that lifted the nose up, then set it down a little hard but I was luckier than you.


Lee,

The reason for down thrust is to prevent the plane from climbing during acceleration. Also with no down thrust if you trim it for level flight at moderate speed then it will tend to climb when you go faster. The amount of down thrust you want is a function of how big an engine you are going to use. Most guys are using 5 degrees.

Based on discussions in this thread at the time I was building I made my mount for 4 degrees. With my Artes Bee (12#) it was fine. Then I put my Wren SS on it dialed down to 14#. That also seemed to be OK. After bumping the engine up to 16# it had a definite climb at higher speeds. I placed washers under the front to get approximately 5 degrees, which is better. I'm guessing that I'll need about 6 degrees when I give it the full 18#.

I don't see any reason not to put in some downthrust. As you alluded to, the other advantage is to help keep hot exhaust away from the horizontal stab. The other alternative would be to mix a small amount of down elevator with your throttle.

Joe

PowerGrunt

Looks like there are lots of mods being done on the falcon 120 kits out there.
Our demo kit was flown at Wangaratta jets here in vic and since then I have had about 6 more flights
great flying model which lands slow, my kit has a PST600 on board and my next mod will be to add a smoker he he

cheers Pete

oistein

My Feedback: (1)

Here is a video of mine with a PST 600 in it also. Very nice turbine !

[link]http://www.youtube.com/watch?v=BMf5s79mj8g[/link]

new2jets

hi joe flew my falcon today at classic jets abingdon, flew it full bore all 18 lb`s 6 degrees down thrust seem perfect but have got up trim in elevator is more in line with the top profile of wing section than flat with the bottom. c/g seem`s good at 13 inches flys inverted with only a touch of down in so i will live with that and i`ve got 2l of fuel on board vertical is very very very very good hope to put video on you tube i will post link .

jonathang

just pack the front of the turbine till you get it to flt level with washers you will then get to trim i out with the elevator level regards jonathan

tim777jet

Ref the elevator position, this has been covered previously, but look at it this way, fly the plane up high, now switch the engine off. Trim the plane to glide perfectly, with the CG correct. This now elliminates any problems with the engine thrust line. I have had 3 flame outs in flight, and the plane glides beautifully with the elevator set as everyone has found, with the top surface level with the top surface of the tailplane. It was suggested that maybe the tailplane rigged position was a degree out and could be corrected by packing the boom trailing edge up slightly, but what does it matter. The elevator section is quite thick and does it matter if it lines up with the top or bottom surface. As cougar man said, just use washers to pack the l/e of the turbine mount, until it flys without climbing when power is increased. cheers tim

Ed

Has there been any news about the release of a new Falcon 120, designed specifically for turbine use ?

> Jim