FalconWings

My Feedback: (57)

I've had it with myY/A Falcon. After four attempts in the last 2 months to get it into the air, I was finally able to take off correctly today.
My first 2 attempts were my fault, I had the CG all wrong, so they ended up in crashes with only minor damages. Last weekend it was the wind's fault, steady at 30 kts, couldn't get it off the gorund.

So I crank up the OS .91, reved up, everything OK. Had a 3-5 kt headwind. I taxi into position, rev-up and off it goes straight down the runway. After about 400-500 ft I roll and almost immediately I retracted the landing gear. The model was trimmed out perfectly!
I stop the climb at about 50 ft altitude because I wasn't getting any airspeed, so I let it dive somewhat (but I don't have that much room to play). It just wasn't accelerating at all. I notice that the engine is still running @ peak very solid. Slowly tried to turn downwind, but to no good it just dove in and hit the ground. At no moment did I loose control of it. I still had positive but sluggish aileron control.

My F-16 just wouldn't accelerate. I am so frustrated right now. I opened the auxiliary inlets as indicated. The engine was maxed out. The dynamax is new. Evertyhing was working. The dry weight was 14 lbs (with the scale cockpit). The wind was perfect and it could only help.

What the hell went wrong?

It kills me to have wasted so much effort in this project, as it was the first jet I've ever built. It looked really good and I was hoping on using it to get my turbine waiver.
It is still very much fixable, all the damage was on the belly, but Im hanging my gloves. I just don't have the time and willingness to fix it anymore. The model will become a decorative piece in my garage.

As for the waiver, I will have to do it on my jet sometime this summer.

David

J. Campbell

My Feedback: (31)

Im sorry to hear that about your yellow. Mine was an A model, sport gear, Flew GREAT. Rotated in about 300Ft but was sluggish untill it got up on step. Which model did you have? As for the sluggish on takeoff, and never gaining speed sounds like the engine, i know you said it was maxed, it may well have been but it could have still been low on power, Did you check your pipe seal, if this goes it will cause this. Russ

trioval00

My Feedback: (17)

david, there are many things that could have been wrong, or just alittle off with the set up,

i was like you, i went thru the ducted fan stage, got fed up and gave up on them, then a few years later i saw a kangaroo fly with a jetcat, had to get one, i bought a facet 2300, the very same bright green one everyone see's, bought it directly from the designer himself, i now have 31 flights with no problems in the past 9 months.

hang the ducted fan, and go straight to turbines, if you can, and you will NEVER look back
a flip of the sticks and it starts everytime, and i have full power.

i have sold most of my ducted fan stuff

enjoy and good luck

mark

FalconWings

My Feedback: (57)

Mark, that is my plan. I just bought my first jet, so Im planning on sticking to it from now on. But regarding the Ducted fnas, i've never had problem with them before. It's been all good, then again it olny takes one to really piss you off.

Te pipe seal is good, checked it as I was cleaning the engine bay. No black residue. The model accelerated well on the runway, I guess it had good static thrust and absolutley no dynamic thrust.

What a shame.

Terry Holston

My Feedback: (1)

Did you have it leaned out too much...........................Power will be good at first then the engine will sag a bit as it gets too hot and starts to sieze. Was there a bit of smoke coming from the tailpipe?????????????? No smoke = toooooooooooo lean. OS .91 needs 23% oil. Use Wildcat 5% Jet A for best results.

FalconWings

My Feedback: (57)

Yeap, a little smoke coming out. The engine didn't seem to rev down. I maxed out the engine by leaning it, then coming back some.

Terry Holston

My Feedback: (1)

In that case Bummer.......................Put a turbine in it.

Sorry for your loss.

FalconWings

My Feedback: (57)

Perhaps later this year I'll go for the ARF turbine ready version. I have the scale landing gear already so might as well.

tschuy

My Feedback: (1)

Rip out that OS .91-dynamax fan configuration out (since it is douptful that it will ever produce 14 pounds thrust or even sufficient thrust to even fly the dang plane) and put in a a Jetcat P60 instead. You'll be glad that you did and the airplane will perform like a dream.

Cheers,

Shaun Evans

Hi,

I, too, am sorry to hear it's not working out for you. I don't have any ideas beyond what these fellas mentioned except to wonder if the aux inlets are opened up? That older model needs them there. If you did have them in place, it seems to me that somehow the engine wasn't putting out the needed thrust. If it really took 500' to rotate, that's a good indication of that as well.

When the bugs/gremlins are gone, that plane flies quite well on DF power. I hope you figure it out and give it another whack.

MNModels

Hi David,

Sorry to hear mate! You stated it was your first DF model and i assume the first DF setup?? I have been flying DF for 10 years now and let me tell you i am still scared of my F16. If you get the angle too steep on lift off the inlet will not work and she will not accellerate until you drop the nose. And because you will not have enough hight she will go in. Once you know what you are doing - it flies! I do not fly mine. I will convert with wren 54 or JJ1400. Wrong jet for first time DF. Just my opinion.

It is a very fine science these DF planes. Turbines work and you will not have to worry about thrust - only flying...

Regards

SJN

This is what you need!

http://bornholm.adsl.dk/modelfly/files/jet/Power.wmv

grbaker

My Feedback: (29)

A friend of mine started out in jets with a YA F-16 with an OS.91/Dynamax and he flew it from a 225' runway. It was the version that did not have the scale gear so it might have been a little lighter.

FalconWings

My Feedback: (57)

Hi Gary, mine was the "C" Polyester version, with scale gear.

Had mi climb been shallower, I wouldn't had climbe at all.

I will post some pics later.

RLPageMD

My Feedback: (3)

Sorry to hear of your problems. Noted that you're in Texas. The past 3 days have set records here in Norman for high temperatures. I wonder if this might not have been a factor. A friend of mine had difficulty with his turbine helicopter not acting quite right when it flew just fine several weeks ago when it was almost 30 degrees cooler. Your difficulties have me thinking of passing up ducted fans too and sticking a turbine in my Yellow single F-18. Good luck with your decision. BRG, Rick

Flyjets

My Feedback: (51)

Falcon

First off let me say I'm sorry I know the feeling and it's not a good one.

After having this same problem on 1 electric jet and 1 ducted fan I now make it a habit of measuring thrust output.

Get a fish scale I use digital or a scale that the nose can lean against and measure the thrust in foot pounds.

2 to 1 is the min acceptable for my standards I find this flys good enough to not feel that sinking feeling you experienced after takeoff.

3 to 1 is what a typical Jet airliner uses so my standard will get u going nicely.

Keep Flying
Ian

FalconWings

My Feedback: (57)

Ian, Im lucky if I can get a .8 ratio. My airframe was at 14lbs, and the Dynamax probably yields close to 12 lbs. My TGA F-15 flew on a Dynamax at 18lbs airframe weight without any problems.

Rick it was flat out 100F yesterday. Wind was next to nothing.

Johng

My Feedback: (4)

Having run the field for multiple RC payload contests, I know how much performance can get eaten by the heat. We tracked temp and humidity and once things start heating up even above 80 deg, performance of nitro engines drops big.

100F is not the conditions for a first flight of just about anything. Less power from the engine, less lift from the wings.

If you have the heart to repair the bird, wait until you can do an early morning flight with temps in the 70s.

rhklenke

My Feedback: (24)

Rick,

Do it! The most miserably unreliable turbine is about 10 times more reliable than a DF. A good turbine (I run JetCats, but there are many other good ones) is the most reliable model powerplant out there. I have well over 300 turbine flights and the only time I've had a flameout is when I've run it out of gas. Turbine models fly SO much better and sound better too. Also, you will notice a drop in power, but you can fly a turbine model on a 100F day - done it many times here in VA.

Go straight to the turbine, you'll LOVE it!

Bob

MMallory

My Feedback: (1)

David,

Check your inlet and make sure it is attached firmly. Sometimes the inlet will collapse. Make sure the inlet is sealed to the shroud. Also check that your fan is on tight. This plane should fly fine with a lot less power. Something isn't right. I would also tach the engine to make sure you are getting the expected RPM. Do you have a remote needle? Maybe a partner could adjust the mixture for you if it is leaning out after takeoff.

Mark M.

Shok

My Feedback: (28)

Yeah David the heat may have played a part.

I flew my AV8R saturday and it was definatley different in this heat. We were measuring 102 at the feild.

Instead of lifting off at the 200ft mark, it didn't get off until almost 350ft and required much more throttle than usual to maintain flying speed.

Bob_B

My Feedback: (11)

Not as reliable as a Brushless motor setup in an EDF. Now if we could just get the power you guys have!

ianober

My Feedback: (12)

Guys, of course your not going to get the performance in the heat that you get when its cooler. The air is less dense, less lift. Your take off roll most definately increases, drastically. This is basic flying principles. I would try flying again in a much cooler evironment, with much more dense air.

Jetman007

My Feedback: (6)

A few things come to mind. I flew a Y/A F16 for a few years on a Dynamax with an OS91. I suspect a number of factors let to your latest crash. Not enough thrust and unfamilar with how thsi plane flies.

Most importantly, you need to ensure you are for sure getting 10 pounds of thrust on the ground. Check with a fish scale attached to the nose strut. If you are getting 8 or 9 it will be marginal.

If you cannot get 10 pounds of thrust, check things out:
- Fuel restrictions can cause you to be lean without developing max power.
- Old or bad fuel (23% oil is a must) 5% or 10%
- Fan rotor on tight and not slipping
- Minimal rotor blades to housing clearance (1/32 of an inch all the way around). If not you get inefficient performance = low thrust
- Air leaks on the exhaust side (get them all closed up so all the exhaust gasses go out the tail pipe not around it)
- Inlet cheater holes as per plans and inlet not collapsing at high power settings
- Pipe working properly and on tight. Also, no loose baffles inside (you can hear them clank if you shake it = No No)
- Pipe pressure working properly
- Too lean or too rich (engine tuning is a whole other story). I assume yours has been properly broken in?

As for the plane flying in hot weather- never had an issue. Sure it took longer to take off when temps were in the 90's and 90% humidity, but it still flew fine. Need to be sure you don't rotate too early or get an overly aggressive AOA too soon. Let it come up "on step" in the first lap around the field. Take off nice and smooth after about a 300+ foot run, at least, then do a shallow climb, into the wind, to about 80 feet altitude to clear any trees, then let it level off and circle the field.
If you rotate too early it causes it to stagger around at high AOA = runs out of altitude and speed.

Good luck. Once you get the bugs out, it's a sweet flying plane. Stick with it.

Dave Presta

My Feedback: (3)

Its common knowledge that heat directly effects the performance of any aircraft ect... the issue here is that I dont think this decrease in performance is what caused this plane to crash. It still should have "Flown" just not as well with the current conditions. When you are ready to try turbines you should get one of Tams new Fun Scale F-16's, designed for the every day/beginner in mind and is a fraction of the cost of most planes out there that do not fly as well. You can have it ready to fly in a weekend and it is designed to be powered by a P-60/Artes Super Bee size engine so it is very affordable and easy to make the transition from Ducted fan to turbine. Just a suggestion.
Hope it helps,
Dave

check it out at www.tamjets.com