[samste]

Funjet has no Rudder.
But a good idea i might install one

Hint
I have never seen anyone do this check on hand launch.

[kizza42]

You took off without one wing attached didn't you ops:

[samste]

lol lol

No

Shall i put kev out of his pain as it could happen to him or anyone who hand launches

[samste]

OK guys here it is !

When throttle is up on plane all controls are lost ailerons and elevator. when throttle off aileron and elevator controls are restored.
Thus Faulty bec in speed controller while throttle engaged which you would pick only if you check your controls while throttle up before launching.
Hey this may be a unusual fault that may not happen again but if your hand launching it maybe difficult to check but might be a worthwhile investment.
As for ground takeoffs you would pick this up straight away.
FYI venom 60amp speedy was the culprit
I HAVE REPLACED IT WITH A HEXTRONIC 80AMP SPEEDY NOW and body all fixed easily and ready to fly.

Steve

[~KevJ~]

ahhh, well there ya go

[samste]

Hi All

I have Noticed Today Flying the Funjet at very slow speeds i am getting the death wobbles (nose goes side to side)

I thinking This is due to my rudder tails not being perfectly square and a bit out of alignment, probably caused from leaving the funjet in van all the time so when i get a chance passing near field to go for a fly.

Found a little about wobbles on web, where they talk about TOE IN /-------------\ where tails angle slightly in wards
to help with this ? not sure about this relating to my issue.

CG issue i don't think because i haven't changed anything and its flown with this setup over 50 flights.

It was A little windy This Afternoon which i gather would contribute a bit with a cross wind.

Flying with med speed no problem.

Will straighten tails up and try to square it up to see if that fixes issue and give it a try as the Funjet does get knocked around a bit in the Van.

Any Tips welcomed

P.s Field is looking a lot better Today though it not going to help with this weekend weather Wash out prediction.

[~KevJ~]

hey steve,
i have this exact problem with my funjet at slow speeds.. i was watching it just this afternoon on a slow pass right before i turned hit it flat stick and blew my motor.. :? damn it!

now to find a new motor...

[kizza42]

One wing stalls, drops and gets lift and then the other follows suit. Canting the tails out might help a bit but since they're already in washout at a high angle of attack it likely wont, you'd get the most benefit from some dihedral in the main cross section (Like how my Stryker looks now!) This directs the air to spill up over the wingtips instead of mid-wing and reduces mid wing stall. Or you can be crazy and do it like RCPowers:
[youtube]http://www.youtube.com/watch?v=1_Eh3pMC-1o[/youtube]

[samste]

Thanks for the Tip Kieran, love the You Tube Clip that is one Awesome setup on that Plane.

P.s Project X is about ready for maiden flight. (Added 100gm Rod to rear tail for Cg Correction)

How Kev Where you running 4s lipo on motor at the time.
Because i had the similar motor on the first Funjet and smoked it too with 4s at flat stick just a bit too long, When i Think of it i smoked quite a few motors on the Funjet to i found the Scorpion Motor That just keeps giving it back.

Steve

[~KevJ~]

yeah it was extended flat stick climbing vertical .. lol
...of course it was! heh.

hey you run 4s on that scorpion yeah?
i may have to get one, was also looking at kierens motor cause its rated for 60a continous..

[samste]

Gday Kev , No I'm only running 3s lipo as the scorpion 2221-8 suggest only 3s ( 3595kv motor)

I think my Funjet has had a battering as the wobble seems to be set in well, I am deciding to use one of my spare Funjet bodies as my nephew is keen to have the old frame and im keen to do a new makeover with better colors and better frame as my new Jetiger body has come out really well and very pleased with the customized power setup i have on it, with plenty of power when you need it and the cg is much better now on the new one with the knowledge i learned from the old frame custom build.
Love The Fluorescent Green Bottom on Jetiger, very visible and contrast seems to be good Too.



Steve

[paulj]

Love that video Kieran.
Very interesting use of gyros.
I was watching a special on tv the other night about the
carrier "Nimitz". I noticed the amount of movement both in
elevators and cannards the jets were using on both takeoffs and landings.
They really need computers to do most of that work as it would be too
much for a pilot to have to control.

Paul

[paulj]

Hi Steve,
love the colours.... You should have no problems seeing that
against a cloudy background.
Look forward to seeing it fly.

Paul

[robair]

Gday Kieran

In regards to your earlier comment:
"you'd get the most benefit from some dihedral in the main cross section (Like how my Stryker looks now!) This directs the air to spill up over the wingtips instead of mid-wing and reduces mid wing stall."

I have to disagree with your explanation of dihedral effect or more correctly "Spiral stability" which is the result of increasing dihedral, dihedral does not affect airflow over the wing as the relative airflows remain unchanged irrespective of dihedral angle. The key is noting the velocity vectors of the vertical component of lift above a wing, or "Centre of Pressure" and how that relates to the velocity vector from the Centre of Gravity, with zero dihedral the Pressure vectors are parallel to the Cof G vector, with dihedral the Pressure vectors are angled in towards the CofG. each time the aircraft banks the dihedral angle will induce a sideslip moment that will change the angle of attack and speed up the lower wing, as lift is a function of speed the low wing will now be generating more lift and thus roll back up to level. Happy to discuss this with you in greater detail and a diagram or two would also help. One other thing to note is that the more air you have spilling over the wingtips the more induced drag you will have. This is most certainly not ideal!!! Directing air to the tips will actually increase the likelihood of root stall and greatly increase your aircrafts stall speed. Many types of aircraft use "Wing Fences" to prevent airflow heading out to the tips to avoid this. I would also like to see the term "Tip Stall" removed from our vocabulary, the term has currency with rotary wings howver no real technical merit in regards to fixed wings.


Cheers
Rob Byrnes

[~KevJ~]

most informative rob, it seems i have a potty mouth as i spray tip stall every chance i get..! ops:

actually i never really put any thought into this side of things im more of a stick man..

[robair]

Nothing wrong with the stick and rudder approach Kev. After all it is the pilot via inputs to stick and rudder that ultimately enables a plane to fly!!! I just can't help myself in regards to hoovering into the technical side having studied it for far too many years.

Cheers
Rob B

[samste]

Wow what was all this about, are we being Invaded ?

Most users ever online was 25 on 11 Feb 2010, 23:28

Steve

[~KevJ~]

Wow what was all this about, are we being Invaded ?

Most users ever online was 25 on 11 Feb 2010, 23:28

Steve

now that is wierd ....

[samste]

I had several flights Today of the Stryker with scorpion Motor off Funjet, At a huge huge enormous flight area which i tell you guys about in person.

This Thing goes like a missile,i think its doing way over km as the stryker frame overall is way lighter than the Funjet was.
But i noticed something quite strange that you experts may clarify for me.

On full throttle plane going like a missile but controlling it is another matter, does not seem to respond so well.

Is it the force of the wind over the frame placing pressure on ailerons that it wont respond as it should, soon as i let the throttle down a bit i can turn left, right. Though elevator up/down works fine.

I did notice one thing that one of my servers is slipping (crook) but that could be from my tumble landing i had on last flight. No damage to plane. could it be that server as top speed there would be a lot of pressure on the servers to move up/down.

Samste

[Stuka]

I have four 1800 3S Lipo batteries that I used to use on the Cub which I am now retiring.

Could anyone tell me if I can use them on the T-28 Trojan which normally uses the 2200 3S Lipo batteries without causing any damage.

Thanks

Victor

[kizza42]

Sounds like you've hit the torque limits of either your servo's, control rods or control surfaces. Be very wary that you haven't stripped a servo doing this as it could be fatal later on. Craig had the same issue when he first put the mini turbine on the back of a stryker, The wings are also much more flexible than on your funjet. It's time to get yourself some metal gear digital servos but I'd back off the speed a bit for the Stryker or reinforce it with more carbon and balsa control surfaces.

[kizza42]

I have four 1800 3S Lipo batteries that I used to use on the Cub which I am now retiring.

Could anyone tell me if I can use them on the T-28 Trojan which normally uses the 2200 3S Lipo batteries without causing any damage.

Thanks

Victor

You wont have a problem, as long as you adjust your flight times for the lower capacity

[Stuka]

Hi Kieran,
Thanks a lot. That gives me another 4 batteries to use while charging the 2200's
As you know I'm rather conservative on flying times anyway!!!

[samste]

Gday all

Kieran Thanks again for Servos. and doing the orders from hobby king.

I'm have now reduced motor top end speed with 3000kv scorpion motor i have, rather than my stock 3595kv that i have been using on funjet that i transfered to stryker which i am now hoping will resolve control issue at high speed as top speed should be a lot less now.

Before installing metal servos should i -
Do you think moving Servos to center of aileron on either side so control horn is connected more to center of aileron rather than on edge will help or a waste of time. ?

Or replace Ailerons with Balsa. ?

Steve

[kizza42]

Why not first just try and stiffen them with paddle pop sticks or some small carbon rod. I wouldn't want to be cutting holes further outboard on the wing and moving the servo

[robair]

Gday Steve

Kieran is spot in regards to cutting up the wing more, you will just lose more rigidity. Another option could be using light fibreglass cloth or the polyurethane sealer to stiffen things up. I know you have also experimented with a gyro, that may also be an option, I was impressed with a video elsewhere on this site of the guy who was using 3 to tame his SU27 thingy.

You may also be going so fast that you are inducing "flutter" on your elevons, this can be obviated by ensuring that you have absolutely no play whatsoever in your control rods/ connections. Flutter can also be caused by harmonic vibrations in the airframe so you may want to also very carefully balance your props. The good bit is that if Craig can wack a turbine on the sucker (how cool is that!!!), and get away with it you know it can be done. Once again back to Kieran's comments you have more than likely merely hit the limits of your servos performance. So some digital MG's would possibly remove all your woes.

Good luck with it, I know you will get her sorted.

Cheers
Rob Byrnes

[samste]

Thanks Rob for the Tip i ended up swapping out to digital metal servers and fitted carbon rod tube along back of Aileron.


Test Flighted down at field today with 3000kv scorpion and she flew nice and control was there at high speed.
Not as fast as 3595kv scorpion but i can live with that for now, as want to trial another motor i have which will be a little slower but much more quieter I'm hoping, its 2700kv rated.

http://www.hobbyking.com/hobbyking/store...s_Inrunner

I do like the scorpion motor as i can fly it basically non stop battery after battery full throttle any time and motor only gets warm. (Its just a loud motor).

Steve

[kizza42]

Motors aren't loud, its the prop!

[samste]

You may be right that its the Prop thats loud but i have found that using in runners for pusher seems to be quieter than the scorpion out runner, Tested motor without prop and and it tends to have resonance noise that seems to be louder once prop is on and vibrates throughout the plane frame.
Tested scorpion motor on bracket in vice and was a lot quieter, so i guess a good motor bracket, well balance motor shaft and prop will help a lot.

Steve

[~KevJ~]

as want to trial another motor i have which will be a little slower but much more quieter I'm hoping, its 2700kv rated.

http://www.hobbyking.com/hobbyking/store...s_Inrunner

I do like the scorpion motor as i can fly it basically non stop battery after battery full throttle any time and motor only gets warm. (Its just a loud motor).

Steve

thats the exact motor i blew up last weekend, i was running 4S 3000MAH at only 20C on a 6 x 4 when she blew so watch the amps with high C rated 4S batteries , also be careful flying on 3s as you will find it hard to stay awake as the performance was slow and boring ...

( i was as usual WOT for extended period of time when i blew her)