Help! Both planes roll left and nose dive

[balsa basher]

hi fello flitefest testers!
I am just getting back into flying after @ 15 years and have no experience with foam aircraft and electric motors. I am really regretting not bringing any plans to flitetest - I went as a spectator only - that is turning out to be a big mistake: I have 2 scratch built planes (duster and bushwacker running with power pack c. I tried to maiden them both and they BOTH roll immediately to the left and nose dive to the ground before I can attempt any corrections!

any thother gets as to why both planes have the same fatal characteristic?

I really did take my time and thought that both planes turned out very well

please try to help if you have a minute

thanks!!!

Balsa basher

 

[Jugsy]

Could be thrust angle, but I'm not sure what angle if any those planes require so I'll leave that to someone more familiar with them. This video explains it really well, really quickly.

Also, how are you launching them? Off the ground or throwing? How much throttle do you have to use? How do your control surfaces look and move on the ground? Pictures and videos help a lot!

15 years is a really long time to let a skill sit, have you considered trying out a simulator to get comfortable again before you crumple any more foam?

 

[balsa basher]

thanks for the response!
I also thought about thrust angle so I am building a new power pod as an experiement

I took off both planes off of the ground given that I have no experience hand launching - never did that with my old gas models

I did check the throws on the ground and they look O.K

one interesting fact related to a question you posed - they take much mor runway to tak off then I see in the videos hen Josh maidens the planes in the build videos

 

[Jugsy]

Might be worth weighing them - wouldn't account for the roll, but would explain a long run up and the nose dive. I assume CG is correct for both?

Also try checking your movements and throws with the motor at full throttle (PROPS. OFF.) to see if you're getting any kind of power loss.

Another tip to avoid wrecking your models before you even get a decent flight in, try a glide test. Battery in but powered off, toss the plane and see if it glides or dives. This will help identify if it's a problem with the airframe or with the setup/electronics.

Also, I noticed you've posted this thread in at least 3 different sections. You probably wanna delete the extras to avoid confusion, or getting the same information 3 times, and also to save the admins some work

 

[balsa basher]

Will do - thanks!

 

[cranialrectosis]

Look for a reversed channel on your transmitter.

 

[N4RF]

I would also make sure that the controls are centered.

 

[BridgeInspector]

Check your esc throttle calibration with prop off. You may not be getting 100% of your available throttle.

Both of those planes should not need a thrust angle.

What battery are you using? And it couldn't hurt to double check the CG and throw directions.

 

[quimney]

just a note...

The duster needs about 2 - 2.5" degrees right thrust in the powerpod to run straight on takeoff. The bushwacker has right thrust angle built into the plans so nothing more is needed.

I fly all of my ~40" FT planes on a turnigy park 480 with a 9x4 prop. This combo gives unlimited vertical but is not crazy overpowered. I flew the duster on a smaller motor and my takeoffs were pretty long.

To get things sorted out I would suggest doing a discuss launch. Hold onto the wingtip and swing it about 180 degrees to get the speed up and just let go. It's an easy way to launch when you get used to it and gives you a chance to work out the flight characteristics before you have to deal with the takeoff quirks.

 

[balsa basher]

Thanks again for your help - as I was going over the bushwacker I noticed that both sides of the elevator were not moving evenly - I think I left too much glue when I was reinforcing the hinge - I cut it out and put in a new one and it looks good - I will let you know if this was the problem - I hope so!

 

[aiidanwings]

More speed and a bit of right rudder.

 

[Capt_Beavis]

Reversed controls is the first thing to check. Even experienced builders do this from time to time. I had it happen on my mini speedster and it took way to long to correct. the rudder being off a bit can also be an issue. I had a Durafly Mustang with almost imperceptible left trim that was almost unlauchable until we figured it out. What props are you using? Too high of a pitch can cause the plane to bank left. I have had this problem on the duster before.

 

[slipshift]

I had (have) the same problem, and in my case it was too much throttle on takeoff. When hand launching it makes a loop over my head and into the ground. I'm a new flier and know what I should do but when I turn on my Tx I get stupid, going full throttle when that was probably the cause of the problem in the first place. Of course I blamed the wind, mild though is was, but tomorrow will be different. Power pack C is the more powerful one isn't it? Maybe ease off on the throttle.

Jim

 

[Hai-Lee]

With the aircraft stationary on the ground and then attempting to take off with full throttle from stationary do the aircraft tend to swing left and have great difficulty taking off straight until the speed has built up sufficiently? If yes then you are suffering from a "P" factor issue and you need to adjust your side thrust angle.

Many persons ignore the propeller fitted as a factor in "P" factor generation, reduce the pitch of the prop by perhaps fitting a SF prop and observe the difference. A SF prop will give greater acceleration when slow but less top speed.

Another thing to consider is that the roll if present needs to be overcome using aileron so the ground speed will need to be such that the ailerons are effective before take off. This means a longer and faster take off run prior to lift off.

Just a warning! "P" factor if not accounted for with side thrust angle will always be present and touch and goes will need to be done cautiously because if done too slow and then full power is applied to climb out the aircraft will just roll left and nose dive into the ground.

If your aircraft tends to "LOOP" over your head on launch at full power then you definitely need to revise the down angle of your motor thrust line because the engine is causing too much lift of the nose either directly or indirectly.

Adjusted correctly for down and side angle a plane regardless of the design will show no trim effects and have no tendency to alter its course or attitude when the throttle is cycled from zero to maximum and return to zero regardless of speed or initial attitude.