RC India

I tried flying my new Dynam Hawker Tempest(From RcBazaar) Which has Tail Dragging retracts and on the first take off it went nose over, I checked the cg position but there wasn't any CG issues according to its manual.Still I shifted my battery a few cm behind and I still Had a nose over.
The third time when I tried to take off it took of but it was heavily tail heavy! Pretty much uncontrollable and i had to put it down in tall grass before anything bad happened.
Battery used is the suggested 2200mAh 4s.
On my Art-Tech Edge 540 I never had this nose over issue.

Please guide me towards correct tail dragger landing and takeoffs.I have flown with Trike geared planes without any issues and this is the first tail dragger I am encountering a problem with.

Thanks,
Prateek Khullar

This is something similar to what is happening to me:
http://www.youtube.com/watch?v=zBIgEsXPgUs

According to the video you have posted...possible occurances....

1. Nose wheel is not perfectly trimmed....
2. assuming nose wheel is perfectly trimmed, ailerons needs trimming.
3. assuming ailerons are also perfectly trimmed, motor mount is not perfectly aligned. Mount may be little bend towards left/right. Mount has to be exactly aligned. Even a small bend in mount can cause automatic slow turns.

1.No NOSE wheel.
2.As I said, I am talking about 'Tail-Draggers', i.e two wheels coming down below the wings and one on below the vertical stabiliser.
(http://www.rc-airplane-world.com/image-files/airplane-undercarriages.gif)
3.The Ailerons don't take a big part in the take off if they are trimmed, otherwise if you are using flaperons/spoilerons you need to take care of that.
4.In general Motor mounts HAVE to be pitched a little towards the right side if you are using CW props and vice versa.

Check if your main gear wheels are freely spinning. Also, try not to give up elevator till you have gathered some speed; this should be done gradually i.e. increase throttle slowly

These are just suggestions. There may be some other issue too. I've had this problem in a scratch build several times. In one case my main LG was too far back, and that was causing the nose-over. Hopefully that will not happen in a ARF/RTF

@Sanjay Sir: I will try to hand launch it a couple of times and get it to balance out straight before taking off from ground. If I don't give up elevator at the beginning will it not start tipping?
Should I learn to take off from grass or will it be okay from a Road?

Prateek: That is a good idea; you can eliminate CG issues. I feel in any case one should not give up elevator till some speed - maybe not full take-off speed, like half at least - is reached. Many people do give full up and full throttle immediately. Works most times, but with a sensitively balanced model, does create problems. Another advantage of gradually opening the throttle (and giving up) is if you have to abort the take-off, there is a higher safety factor.

As I said, these are suggestions.

Grass or road? You are a lucky man if you have a lawn to fly off :D :D

Frankly, road is harder, but grass drags on and slows down the wheels.  :giggle: :giggle: :rofl:

That's true! :giggle:
I am lucky that I have a college football ground nearby where I fly and I fly on beaches as well(mostly Fpv).
Unlucky because there is literally no one who can come to fly together! :-\
The ground: http://www.youtube.com/watch?v=GVPFxEJTfbo

Nose tipping down is a natural issue with Tail Draggers.... reason... the thrust line tends to be above the drag line (on ground) and it tends to creat a couple which tips the nose down.  I am also using tail draggers and have faced this.  My solution... if possible place the set of nose wheels a bit more ahead of the present location... i.e towards the nose.... that way the couple force required to tip the nose over becomes more and hopefully it will not be reached.
Secondly.... the rotating prop behaves like a Gyroscope which has the properties of Rigidity and Precision (refer physics chapters on rotating mass around a centre) Refer:- http://electriciantraining.tpub.com/14187/css/14187_130.htm (http://electriciantraining.tpub.com/14187/css/14187_130.htm)
Due to this nowdays in most big / sophisticated aeroplanes using propellers they have the propeller running at constant speed.  The power changed at operating RPMs are acheived by changing the pitch of the propeller.  OK........ now if we open less power and run the model and thereafter open full throttle.... we are changing the RPM of the propeller quite fast..... maybe from 4-5000 RPm to about 10000 +.  Going back to the properties of Gyroscope, this action is going to creat a turning force in the propeller disc which can be strong enough to make the model turn to a side... or tip over.

My experience and understanding.... Open full power and then release the model.... OR else build power to max power soon enough i.e. before the model has much speed on ground.

Happy and safe Flying

Keep the elevator up during the take off roll. it will help in keeping the airplane firm on ground during taxi.    Keep elevator full up during taxi.  as the speed build up ease on elevator, then keep the elevator up to the level it is required for lift off.  if you do dry run on ground couple of times at slow speed and increased speed, it will make you understand your airplane's behaviour better before you finally decide to leave the ground.

Also, try to take off from level and clear ground.  Small patches of dense grass can create resistance for wheels while aircraft tries to mantain same or increased speed depending on your throttle input.