What went wrong?

[TWE75]

Hi guys , today when i tried to fly my kinect800 , it just go up abt 1 meter up and away then nosedived onto the ground . I was told to use 50% throttle by the seller but i thought i want to see if abt 3/4 throttle will work anot cos i thought at the most the plane will just glide to the ground and i did tried to give it some elevator when it nosedived to see if i can make it fly up anot . But prove i was dead wrong , it just dived to the ground ending with its broken nose full of " shit " . I already glued it back , letting the glue set for a day or more depend on my free time . I already checked the cg before i throw it out so i don't understand how it can nosedive instead of gliding down to the ground .

So i just want to know if its because of the reduced throttle that cause it to crash or is it because i didn't throw it hard enough , or will the propeller which is very slightly pointing downward due to an earlier repair will cause it to fly downward .

I just want to know what did i do wrong , cos i really like this plane as it is small enough to be flown freely at smaller fields .

[foxkilo]

(1) Do you have enough throw on the horizontal stabilizer? They are single piece, all-moving and very effective - in fact, should not have too much throw. You can download the Multiplex Merlin manual to get the guidelines for control surface throws.

(2) Are you using 2s or 3s? On 3s, 3/4 throttle should ensure enough power to hand-launch. Even without power, just throwing the glider, it should glide smoothly to the ground if CG is okay.

(3) You have a dead or unreliable servo... If you're using the stock servos, they are quite notorious for sudden failure; read the comments on the HK site. Happened to me too, after a couple of uneventful flights, my Kinetic decided to pitch up straight into vertical right after hand-launching... turned out to be a bad servo.

[kiply]

+1 for Foxkilo feedback. I also think you need to check the following:

1. Motor thrust angle - you mentioned the plane had crashed earlier. This could have caused the motor thrust angle to be off, and force the plane downwards.

2. Elevator direction - check the elevator is in the right direction. Sometimes even experienced flyers can get this setting wrong. If you pulled down on your elevator stick and the plane dived, this is surely error in elevator setting.

My experience with the Kinetic is once you have a nosedive crash, ditch it. The foam is too soft to withstand strong impact. You would be better off salvaging whatever electronics and get a Multiplex Merlin kit, which in my opinion is much better.

[foxkilo]

Some more pointers:

If your motor thrust is angling slightly downwards... this should be correct - the Kinetic comes like that. This slight angle downwards will tend to pitch up the nose slightly when you throttle up.

One problem I find with the Kinetic also is that when re-fixing the prop and spinner onto the motor shaft, it is quite tricky to get the spacing correct. Check that the motor is not having any obstruction such as the spinner rubbing on the motor cowling, etc.

Obstructions and friction can cause the motor to overload when you throttle up... drawing a large current and causing the ESC to cutoff just when you need it to work!!

+1 to the suggestion to just spend your money on a MPX Merlin kit. Not just foam, but the plastic is much better quality. At about S$100 for the kit, just a little bit extra compared to the Kinetic kit, saves you a lot of high blood pressure!

[TWE75]

So can i use 3s 850mah battery on the multiplex merlin .

And when i give down elevator to make it fly up for the kinectic isit the front end of the elevator go up while the back end go down right ?

[Starscream]

If you are switching planes, recommend to you the Mini Swift. Sold at the online store in hong kong that gets censored here and Jethobby.

[foxkilo]

So can i use 3s 850mah battery on the multiplex merlin .

And when i give down elevator to make it fly up for the kinectic isit the front end of the elevator go up while the back end go down right ?

You answered your own question...

That's the source of your problem! When you input elevator stick down, to drive the nose up, the leading edge (front end) of the horizontal stabilizer should go DOWN.

Remember that doing this forces the tail down, so nose will go up. Since you got it in reverse, of course your Kinetic nose-dives immediately after takeoff...

Reverse your elevator channel and problem is solved.

Recommend you read up on some basic aerodynamics and flight control, so that all these control surface movements and their effects become familiar to you.

[TWE75]

Thanks alot foxkilo and kiply . Now i know what i did wrong , i will try to fix up the kinect and adjust my setting then i will try to fly it again . Recently i having abit of money problem ... hp spoil also wondering to repair or to get a new one . But many of the contact from our bro here was still in my old hp . Unable to retrieve unless o get it repaired also . One of our bro here also pm me to soak the foam in hot water first before repair so that can glue better . But i already glue it but nvm , at least if got next tme then i know how to do it the proper way .

By the way , i read up on how a plane fly before and some of its aerodynamic but maybe i have forgotten about it lol . Anyway , i may need to do fibreglassing for my other 2nd hand plane to strenghten its cowling cos the motor tend to vibrates strongly at 50% throttle . Shoult i use plywood or fibreglass to strenghten it ?