I broke my tundra v2. Fixed it (iffy). Safe to fly till replacement parts come?

[Xeno7]

After a major crash, plane now vibrates quite a bit when throttling up. Prop looks ok same for prop adapter.

 

Normally the prop breaks or the prop adapter snaps. Safe to fly? Never had this issue before. 

 

Tundra v2

[leccyflyer]

After a crash, if experiencing such vibration you need to find the source of that vibration and cure it. It's far better to investigate and resolve that vibration on the ground, rather than just send the model up and keep your fingers crossed that everything will work out fine.

 

A while back I'd noticed some additional noise at full throttle on my EFlite P51, but didn't pay attention to those warning signs. The motor departed the model at height, swung underneath the nose, suspended on the motor wires and chopped o chunk out of the nose, breaking the prop. Luckily it happened in a position where I was able to make a safe emergency landing without causing any more damage. Back on the bench the post-mortem revealed that all four motor mounting bolts were missing. That didn't happen in one single event and the noise at full throttle was a clue to a problem that should have been sorted out. I was able to repair the model, sort the problem out and fly the model regularly.

[Don Fry]

Bent prop shaft?

it will be down on power. Whether it safe is another matter,who knows, vibration can affect electronics. Don’t know,

[Xeno7]

Ok. 

I already figured the source to be the prop adapter. 

Bit bent. 

 

I honestly don't know how vibration affects the fc. If I can get it down to acceptable levels I'll keep flying but otherwise it'll be more waiting. 

 

Was having a blast w the tundra Untill it just... Dropped? I can't review ardupilot logs right now as the USB thing that connects to ardupilot somehow fell off mid flight. Looked like a stall, no idea how that happened as I was at a safe speed. Likely I just turned too hard. 

 

Then again, the nose fell off my plane several times before. 1h and now it's fixed

[leccyflyer]

Might you be able to put the prop adapter in a vice, slip a piece of metal tube over the end and gently bend it back straight?

[Martin Harris - Moderator]

With sufficient elevator power a stall (or airframe failure) can occur at any speed.  When turning, g loads increase, increasing the effective stalling speed (technically a stall relates to the angle of attack) by requiring additional lift to maintain height. At 60 degrees of bank, an aircraft effectively weighs twice as much. 
 

A practical example was my 1/12 scale combat models which I set up the elevator movement to just not flick into a stall at full throttle and full elevator in a tightly banked turn.  

[Simon Chaddock]

I would not advise 'straitening' an aluminium prop adapter. The ally alloy used is strong but quite brittle as the process of bending alters its molecular structure. Bending it back just makes it worse. They are not that expensive to replace.

The biggest risk with excess vibration is that it will loosen the motor mounts.  

[SIMON CRAGG]

I WOULD NOT FLY IT, until you get rid of the vibration, its a model killer.

 

Bad vibration can tear the motor out and possibly injure somebody.

 

I have seen this happen, and its very dangerous.

 

Have a trawl on the internet and get a couple of spare adaptors.

 

If its only a cheap motor, it might be cost effective to replace, as the motor shaft may be bent as well.

 

Good luck, but electric motors do not like being bounced of the ground!.

[Shaun Walsh]

2 hours ago, SIMON CRAGG said:

I WOULD NOT FLY IT, until you get rid of the vibration, its a model killer.

 

Bad vibration can tear the motor out and possibly injure somebody.

 

I have seen this happen, and its very dangerous.

 

Have a trawl on the internet and get a couple of spare adaptors.

 

If its only a cheap motor, it might be cost effective to replace, as the motor shaft may be bent as well.

 

Good luck, but electric motors do not like being bounced of the ground!.

Agree, a fellow club member's model lost a prop blade just after take off, the motor was out and flying on its own before he could shut the throttle, model disappeared behind the club house and "landed" in the car park. 

[trevor wood 2]

I can confirm Shaun’s story is true. Mea Culpa. A definite case of “I learned about flying from that”, to use the words of the inimitable Wing Commander Spry.

[paul devereux]

13 hours ago, Xeno7 said:

Ok. 

I already figured the source to be the prop adapter. 

Bit bent. 

 

I honestly don't know how vibration affects the fc. If I can get it down to acceptable levels I'll keep flying but otherwise it'll be more waiting. 

 

Was having a blast w the tundra Untill it just... Dropped? I can't review ardupilot logs right now as the USB thing that connects to ardupilot somehow fell off mid flight. Looked like a stall, no idea how that happened as I was at a safe speed. Likely I just turned too hard. 

 

Then again, the nose fell off my plane several times before. 1h and now it's fixed

A replacement prop adapter isn't expensive. Vibration will cause more damage.

[Xeno7]

Guys. Understood. Ok. 

 

Replacement prop adapters take a long time to get to me. This time I'll buy five and some spare parts for when the airframe eventually breaks in a way not repairable by me. 

 

[Piers Bowlan]

Are you sure it is the ‘prop adaptor’ that is bent? It looks like a substantial chunk of aluminium.
Is this the Motor fitted to your Tundra:-

 

https://hobbyking.com/en_us/durafly-tundra-3636-900kv-replacement-motor-w-mount-and-propeller-shaft-suits-v1-v2-night.html

If you remove the prop and run the motor does the end of the motor shaft wobble? Is there still vibration with the spinner removed? Have you tried balancing the prop?

 

The motor may have partially come adrift from the model or you may need a new motor. In any event further investigation could be a good idea. 👍 

 

 

Edited April 15, 2023 by Piers Bowlan

[Xeno7]

I forgot to mention this!

 

I removed the prop adapter entirely and the motor works as normal (aka the day I brought the plane, more or less)

The prop looks 98% fine. Looked exactly the same before the crash and after - minus new grass stains.

 

Before the crash I couldn't feel vibrations in the plane at all.

 

 

I might buy a pusher prop plane as my next one to not break so many prop adapters every time I miscalculate a landing, stall speed, or something else.

[Xeno7]

On 15/04/2023 at 09:57, Piers Bowlan said:

Is this the Motor fitted to your Tundra:-

Yes

 

[Jake Bullit]

Check the motor mount also.

[SIMON CRAGG]

A word of warning.............

 

Pusher props are VERY dangerous unless you are VERY careful.

 

They chew through fingers for fun if the hand launch is not thought through carefully.

 

Probably break just as many props!.

[Jake Bullit]

A pusher on something like an Aeroscout should be fine.

[Xeno7]

Ive flown a pusher prop plane (actually it was my first plane. kinda dissasembled itself completely then I gave up on it) before

 

Solution to your described issue?

Landing gear

 

And not starting prop till after ive thrown it if I have to throw it, or being insanely carefull.

[Lima Hotel Foxtrot]

4 hours ago, SIMON CRAGG said:

A word of warning.............

 

Pusher props are VERY dangerous unless you are VERY careful.

 

They chew through fingers for fun if the hand launch is not thought through carefully.

 

Probably break just as many props!.

Props are not dangerous; people not being safe around planes are dangerous.

[Xeno7]

I totally agree

 

 

[SIMON CRAGG]

Maybe I should qualify the statement, as it seems to have caused some confusion.

 

Hand launched rc models with a pusher prop, are by their very design more likely to cause a hand injury than the same type of model with a tractor prop,

 

This is because as the model is launched, (under power), the spinning prop passes over the hand / wrist area.

 

I have seen props take a "bite" of flesh on quite a few occasions.

 

Fairly obvious really.

 

Safe flying is no accident.

[Xeno7]

I still agree 

I probably don't need to say this but I wasn't confused, and I already knew the risks of where do you put your prop. 

 

Seeing as I might be looking at a pusher prop plane w landing gear it probably would mean I could be a bit more flexible with landings - The tundra v2 easily hits the ground w it's prop if u mess up the landing (I got a snapped propeller) - while w a pusher prop you just grind the nose into the ground. 

 

Or a tractor prop (idk how this is called) that is tail mounted on a seaplane someone in this forum reccomended to me. 

[J D 8]

            Pusher props is the name given to ones that will send air in the correct direction when fitted to an IC engine on the rear of an aeroplane, the engine still rotates in its normal anticlockwise direction.

  Some old side port and reed valve engines like Mills, or Cox are happy run in either rotation so a normal tractor prop fitted the correct way can be used as is the case with electric motors.

[Simon Chaddock]

The potential danger of hand launching pushers does depend on their design.

A pod mounted pusher above the wing, like a Bixler, is as safe to hand launch as any tractor and a belly landing no longer put the prop at risk.

A slightly better aerodynamic solution is to mount the wing and pusher motor on a pylon above the fuselage. With the thrust in line with the wing it has less power on/off trim changes.

My favoured pusher solution.

 Now 5 years old, hand launch (or belly take off!) and belly land, surprisingly powerful and it still has its original delicate slow fly prop.

Note the prop is some way behind the wing and pylon. Improves the prop efficiency and keeps the noise down.😉