Fiti In-flight Adjustable

[BirdDog]

I have the same prop, although I top out at 115 so maybe he has the 914?

[skippydiesel]

Just had a  thought (dangerous):

 

Bristell stated he had the cruise (course) setting to 5500rpm WOT.

 

He made no mention of the take off/climb (fine) setting which should be 5200 rpm Static - could this have some any sort of impact on the pitch motor?

[Thruster88]

31 minutes ago, BirdDog said:

I know this thread is old. But wondering what the outcome was?

I will guess that no AD (airworthiness  directive) was issued. This is good $$ wise for the owner not so good if a crash results.  This is a known issue. Disclaimer,I fly certified and non certified aircraft. Constant speed or in flight adjustable propellers will mask engine performance issues. There were crashes in ww2 when pilots  attempted takeoff with the propeller set incorrectly.   

[Thruster88]

14 minutes ago, skippydiesel said:

Just had a  thought (dangerous):

 

Bristell stated he had the cruise (course) setting to 5500rpm WOT.

 

He made no mention of the take off/climb (fine) setting which should be 5200 rpm Static - could this have some any sort of impact on the pitch motor?

No

[skippydiesel]

1 minute ago, Thruster88 said:

No

Educate me.

[Thruster88]

1 minute ago, skippydiesel said:

Educate me.

The pitch adjustment motor on this type of electric variable pitch propeller runs between the fine and coarse limits. Both the fine and coarse limits have a switch to stop the motor at the limits. It doesn't give a shit what the pilot is requesting if it is within the limits. 

[BirdDog]

Yeah as above. It’s a pretty rudimentary system. Just a 3 way rocker. In the middle there is nothing. Push it forward and it runs the motor to full fine until the stopper stops the motor.  Pull it backwards and it goes full course the same way. 
 

Regards having it set too course for take off - after my run up and I’m all, I have added a step to my checklist to run up to make sure it hits more than 5200 on the ground.  Takes 5 seconds to do and confirms the prop is in full fine. 

Edited September 4, 2021 by BirdDog

[skippydiesel]

14 hours ago, Thruster88 said:

The pitch adjustment motor on this type of electric variable pitch propeller runs between the fine and coarse limits. Both the fine and coarse limits have a switch to stop the motor at the limits. It doesn't give a shit what the pilot is requesting if it is within the limits. 

 

13 hours ago, BirdDog said:

Yeah as above. It’s a pretty rudimentary system. Just a 3 way rocker. In the middle there is nothing. Push it forward and it runs the motor to full fine until the stopper stops the motor.  Pull it backwards and it goes full course the same way. 
 

Regards having it set too course for take off - after my run up and I’m all, I have added a step to my checklist to run up to make sure it hits more than 5200 on the ground.  Takes 5 seconds to do and confirms the prop is in full fine. 

Thanks guys -  Although I have a CS endorsement, it was achieved in GA/hydraulic systems. I think I understand the  principals but have little practical experience with electric CS/IFA.

 

On an erlier point - replacing a $700 motor. I do know that there is a huge selection of stepper/linear drive motors in the market place - would one of these not be a cost effective substitute for the obvi0sly problematic one supplied by Fitti.

 

And

 

Could this be a motor overload, coursed by a misalignment/binding in the mechanism, rather than a motor problem?

[BirdDog]

I don’t know but I’m also going to ask the question of Fitti as to what happens if the motor dies at full course. 
 

My last woodcomp would go full fine if it failed in flight. 

[skippydiesel]

1 hour ago, BirdDog said:

I don’t know but I’m also going to ask the question of Fitti as to what happens if the motor dies at full course. 
 

My last woodcomp would go full fine if it failed in flight. 

Would speculate, that neither full fine (as in take off/climb setting) or full course (as in cruise) would not really present as much of a drama - you could still proceed to the nearest suitable landing ground/airfield and land (not crash).

[skippydiesel]

1 hour ago, BirdDog said:

I don’t know but I’m also going to ask the question of Fitti as to what happens if the motor dies at full course. 
 

My last woodcomp would go full fine if it failed in flight. 

On another speculative idea; could your motor somehow be being repeatedly and very briefly being energised, (pulse not registered by pilot) in the cruise pitch setting? If this was happening the motor to act against a spring under tension and possibly overheating.

[BirdDog]

I don’t know mate. Mine is working perfectly.  460 hours in and still going good. 

[skippydiesel]

I guess, I am hoping GB will make some comments as it is his IFA that is giving trouble.

[BirdDog]

Looks like GB is not here anymore?

 

Would love to know how he is getting close to 130kts in that machine!