WattFlyer RC Electric Flight Forums - Discuss radio control eflight

WattFlyer RC Electric Flight Forums - Discuss radio control eflight (https://www.wattflyer.com/forums/index.php)
-   Beginners (https://www.wattflyer.com/forums/forumdisplay.php?f=7)
-   -   The Apprentice 15e.... guess what.... (https://www.wattflyer.com/forums/showthread.php?t=75973)

woodmangler 06-06-2015 04:48 PM

The Apprentice 15e.... guess what....
 
Fluttering elevator ... fluttering like crazy:mad:

I think it is even worse than before! Now there is the addition of the entire rear of the plane going up and down. Just like the video Rockin Robbins posted.

It was so bad I really was nervous about testing it for very long. Keeping in mind all the things I have read here I flew and landed 3 times.

It is definitely much worse on a gentle down slope

Full throttle into the wind or climbing it was barely noticeable.

With the exception of the electronics, the entire plane is new.

I want to make sure y'all know that I installed everything with a lot more care than the manufacturer did on my first Apprentice. In other words, neater, cleaner, adjusted within a nit on a gnats nut... if you know what I mean. Funny, I really enjoyed that process.. might have to build me a plane!

Assumptions I am making at this point:

All Apprentice's don't do this... so there is a problem with the electronics (read receiver right?)

It is NOT a speed issue... the plane's elevator was going crazy and the plane barely had enough speed to keep it from losing altitude.

I am not going to fly it until I get a new receiver - I think that must be first right?

If someone could post a link to a receiver to buy I would be very grateful. I am NOT wanting anyone to do the work for me, or being lazy... I have been reading and reading and reading and truth be told, these web sites assume you know something about the electronics... I do not ..... yet.

Post Script: The plane flew so well... man, just looked so awesome against the blue Georgia sky with a few clouds... looked like a post card. It was killing me to have to fly so slow due to the tail-from-hell....

pizzano 06-06-2015 05:00 PM

Consider a Spektrum AR400 if you are using a Spektrum DSMX, DSM2 compatible TX......

Wrongway-Feldman 06-06-2015 05:56 PM

Ok. Shot in the dark here.
What frame rate are you connecting to the receiver with.
11ms or 22ms?
Your apprentice is using digital servos as I understand it.
I remember reading a response from horizon hobby to a support question about mixing digital and analog servos.
The service rep specifically said to use a 22ms frame rate with their digital servos or servo jitter will result.
Let's think about what happens when you add servo jitter to an asx3 system.
The servo would constantly move past center which will cause the asx3 system to compensate. This would keep happening faster and faster till the entire tail surface is fluttering.
This would probably not manifest in static testing as there is no resisting force against the servos.

My advice is go into your radio's system settings a set your frame rate from auto to 22ms and give it one more try.

solentlife 06-06-2015 06:07 PM

Given that a Lemon or Orange Rx can be had for peanuts - I would buy one of those and swap out the Spektrum one. You can get Stabiliser Gyro Rx's in Lemon and Orange - but I have feeling you don't need that. Get a non stabilised version ..

Nigel

JetPlaneFlyer 06-06-2015 07:05 PM


Originally Posted by woodmangler (Post 975818)
It is definitely much worse on a gentle down slope

Full throttle into the wind or climbing it was barely noticeable.

So I'm reading this as it only shows up significantly if you dive at full throttle?... yes?

If so 'easy' answer is pretty obvious, you are going too fast, don't dive at full throttle. To be honest is could be that all Apprentices do this, the one you found a video of earlier clearly had the same issue. I've never actually flown one around like a pylon racer, it just didn't seem appropriate for the type of plane it is so quite probably the ones at my field would do it too if provoked. The Apprentice is much happier just cruising around at 1/2 to 3/4 power like a basic trainer is intended to fly. It's not unusual to have to be careful about exceeding a planes maximum safe speed in a dive. It applies to all full size planes and you need to be carefull with many RC planes too.

If you want to be able to go flat out in a dive then I think you will have to stiffen the tail up. 2mm carbon rods to form a tail brace should do the trick.

Rockin Robbins 06-06-2015 07:07 PM


Originally Posted by solentlife (Post 975822)
Given that a Lemon or Orange Rx can be had for peanuts - I would buy one of those and swap out the Spektrum one. You can get Stabiliser Gyro Rx's in Lemon and Orange - but I have feeling you don't need that. Get a non stabilised version ..

Nigel

Totally agree. Get a radio receiver with no bells and whistles, Lemon or Orange. Then when the plane flies great you can get a gyro stabilized version of either and they work great.

Now, you should e-mail Horizon, link them to all the discussions we've had here, carefully calling attention to how their inattentiveness has resulted in real damage to Horizon's reputation and ask if they can make you into a happy customer who will spend equal amounts of energy telling everyone how GOOD it works and how they stepped up to the plate and finally solved your problem. You've jumped around to new threads all over the place here and been difficult to follow, but I'd link them to ALL of them.

Someone looking at Wattflyer and considering an Apprentice wouldn't be too likely to pull the trigger right now. But they have a golden opportunity to fix this! <smile>

And don't say anything after that. You want pure, oppressive silence, because the first person to say something loses. Make THEM say something first and then reply hesitantly. Mention that because of their inattentiveness the only reason you're flying right now is because you paid for their mistakes, and they've cost you <dollar amount goes here>. Be very silent again. They must talk first or you lose.

In other words, back 'em down and then back 'em down again. Then if they follow through, do what you say. Post about how they fixed your problem and how you're a happy camper now.

If they don't help maybe it's time to go to that other forum we don't mention around here (RC Groups) and tell THEM what your experiences have been.

If Horizon's going to turn over a new leaf and become a customer no service company, everybody deserves to hear about it.

theapplepi3.14 06-06-2015 07:26 PM


Originally Posted by Rockin Robbins (Post 975826)
Totally agree. Get a radio receiver with no bells and whistles, Lemon or Orange. Then when the plane flies great you can get a gyro stabilized version of either and they work great.

Now, you should e-mail Horizon, link them to all the discussions we've had here, carefully calling attention to how their inattentiveness has resulted in real damage to Horizon's reputation and ask if they can make you into a happy customer who will spend equal amounts of energy telling everyone how GOOD it works and how they stepped up to the plate and finally solved your problem. You've jumped around to new threads all over the place here and been difficult to follow, but I'd link them to ALL of them.

Someone looking at Wattflyer and considering an Apprentice wouldn't be too likely to pull the trigger right now. But they have a golden opportunity to fix this! <smile>

And don't say anything after that. You want pure, oppressive silence, because the first person to say something loses. Make THEM say something first and then reply hesitantly. Mention that because of their inattentiveness the only reason you're flying right now is because you paid for their mistakes, and they've cost you <dollar amount goes here>. Be very silent again. They must talk first or you lose.

In other words, back 'em down and then back 'em down again. Then if they follow through, do what you say. Post about how they fixed your problem and how you're a happy camper now.

If they don't help maybe it's time to go to that other forum we don't mention around here (RC Groups) and tell THEM what your experiences have been.

If Horizon's going to turn over a new leaf and become a customer no service company, everybody deserves to hear about it.

agreed. This apprentice is for beginners, and should be able to take lots of abuse but this happens in BEGINNER mode too (as you said)! AS3X shouldn't be limiting top speed as much as it seems to for you. My Delta Ray can hit over 50mph in a 1000ft vertical dive with only tiny amounts of manageable oscillations that were only visible when I looked at the onboard footage later. I remind you this plane is a SAFE plane as well.

Swiss Flyer 06-06-2015 07:27 PM

I've had two apprentices and can confirm that the first had tail flutter on full throttle (only in expert mode) but the second does not. In my mind the first plane had a gain issue with the receiver and was experiencing some form of positive feedback loop. Since the first plane is now gone I cannot test my hypothesis with a new receiver, but that is where I would have put my money.

birdDog 06-06-2015 07:41 PM

I just got back from the field with a Lemon 7ch plus stabilizer. 10-20mph crosswinds. Tower Hobbies 39" EPP Hellcat RxR. This plane flew great without the gyro but with it, it is a LOT more fun. Could be an option for you. Gear channel toggles it on or off. With it on, the plane feels like it has about twice the expo programmed in. Amazingly stable in gusty, crosswind landings and ROG takeoffs.

Lower your ELE gain if you can WM.

I had a bit of aileron wobble on fast dives and turning in to the wind at higher speeds. Dropped the gain 10% on AIL and problem was gone.

http://www.lemon-rx.com/shop/image/c...00-320x320.jpg
http://www.lemon-rx.com/shop/index.p...product_id=107

In short. The best $27 DSMX RX I have flown to date.

Yeah, she's a pretty one!

http://www.towerhobbies.com/products...wa2004_225.png
http://www2.gpmd.com/image/t/towa2004.jpg

JetPlaneFlyer 06-06-2015 08:22 PM


Originally Posted by birdDog (Post 975831)
Lower your ELE gain if you can WM.

As far as I'm aware on the Apprentice Rx gain is not adjustable.

PS.. I've had great results with the Lemon Rx stabiliser too, but of course it won't give the self leveling and attitude control that the Apprentice SAFE system does, if that's needed.

birdDog 06-06-2015 08:45 PM

One thing that just crossed my mind. If you have the AS3X mounted directly over the CG, perhaps moving it back an inch or two may give some benefit. I dunno, just a guess. Would this possibly be a hack to reducing the elevator gain mechanically or at least stretch out the oscillation?

woodmangler 06-06-2015 10:02 PM


Originally Posted by Wrongway-Feldman (Post 975821)
Ok. Shot in the dark here.
What frame rate are you connecting to the receiver with.
11ms or 22ms?
Your apprentice is using digital servos as I understand it.
I remember reading a response from horizon hobby to a support question about mixing digital and analog servos.
The service rep specifically said to use a 22ms frame rate with their digital servos or servo jitter will result.
Let's think about what happens when you add servo jitter to an asx3 system.
The servo would constantly move past center which will cause the asx3 system to compensate. This would keep happening faster and faster till the entire tail surface is fluttering.
This would probably not manifest in static testing as there is no resisting force against the servos.

My advice is go into your radio's system settings a set your frame rate from auto to 22ms and give it one more try.

Just being totally honest here... I have absolutely no idea what you just said.

woodmangler 06-06-2015 10:04 PM


Originally Posted by solentlife (Post 975822)
Given that a Lemon or Orange Rx can be had for peanuts - I would buy one of those and swap out the Spektrum one. You can get Stabiliser Gyro Rx's in Lemon and Orange - but I have feeling you don't need that. Get a non stabilised version ..

Nigel

What is the difference between the orange and lemon?

I don't need the stabilized version... is that the difference between orange and lemon?

woodmangler 06-06-2015 10:12 PM


Originally Posted by JetPlaneFlyer (Post 975825)
So I'm reading this as it only shows up significantly if you dive at full throttle?... yes?

If so 'easy' answer is pretty obvious, you are going too fast, don't dive at full throttle. To be honest is could be that all Apprentices do this, the one you found a video of earlier clearly had the same issue. I've never actually flown one around like a pylon racer, it just didn't seem appropriate for the type of plane it is so quite probably the ones at my field would do it too if provoked. The Apprentice is much happier just cruising around at 1/2 to 3/4 power like a basic trainer is intended to fly. It's not unusual to have to be careful about exceeding a planes maximum safe speed in a dive. It applies to all full size planes and you need to be carefull with many RC planes too.

If you want to be able to go flat out in a dive then I think you will have to stiffen the tail up. 2mm carbon rods to form a tail brace should do the trick.

I was not even close to full throttle... less than 3/4 throttle and even less - seems like the slight downward angle made it worse

woodmangler 06-06-2015 10:17 PM


Originally Posted by birdDog (Post 975833)
One thing that just crossed my mind. If you have the AS3X mounted directly over the CG, perhaps moving it back an inch or two may give some benefit. I dunno, just a guess. Would this possibly be a hack to reducing the elevator gain mechanically or at least stretch out the oscillation?

I mounted everything where the foam indentations/boxes are .... every electronic has a little foam box

Abuelo 06-07-2015 12:26 AM


Originally Posted by woodmangler (Post 975840)
What is the difference between the orange and lemon?

I don't need the stabilized version... is that the difference between orange and lemon?

WM, both are after market DSM2 receivers that are very reasonably priced. I only have experience with the Lemon and have had zero issues. In their words:

"Note:
1) This is not a Spektrum DSMX or DSM2 product, nor is it a copy of a Spektrum DSM2 or DSMX product. The Spektrum, DSMX and DSM2 brand is a trademark of Horizon Hobby, Inc.
2) This is not an underground black market fake Spektrum product. Lemon Rx quality is guaranteed.
3) Lemon Rx products are tested to be compatible with Spektrum's DSMX and or DSM2 product (Spketrum, DSMX and DSM2 are the registered trademark of Horizon Hobby, Inc.)."

Have heard (but cannot document how accurate, when or where) that Lemon uses higher quality components. Their price is $5.75 each or $26.20 for five. Prices go up for more complex receivers.

Website is http://www.lemon-rx.com/shop/

fhhuber 06-07-2015 01:00 AM

I have only tried some of the early Orange "park flyer" RXs... 1st DOA, 2nd had a max range of 25 feet. 3rd worked for a while.

birdDog 06-07-2015 03:38 AM

I'm running a handful of Orange 620's with satellites and a couple 3 channel long antenna versions with 100% success rate at full range.

JetPlaneFlyer 06-07-2015 10:29 AM


Originally Posted by woodmangler (Post 975841)
I was not even close to full throttle... less than 3/4 throttle and even less - seems like the slight downward angle made it worse

ok, so if it's doing it at part throttle that makes it all the more strange.

The non-stabilised Rx would be a way to at least rule out the possibility that it's gyro gain. I'd second the previous recommendation for Lemon Rx brand receivers, I use them in all my planes and helis these days. I actually prefer them to genuine Spektrum receivers and they are so cheap that it's not too much of an investment even if it turns out not to be the issue. I've had nothing but good results with Orange Rx receivers too but prefer the design of the Lemon Rx versions.

In the meantime if you fly just keep it slow and avoid diving under power.....

woodmangler 06-07-2015 01:21 PM

OK. Lemon on the way
 
Ordered the Lemon DSMX compatible receiver. Gets here tomorrow - gotta love Amazon insta ship stuff :D

Tried using the "Contact us" on the HH web site - doesn't work. Wont sign me in, wont send me a new password, nothing... considering the last phone call with them, and if I was paranoid... hmmm...

solentlife 06-07-2015 02:35 PM

Just a cut and paste from a manual ..... I was interested to look through all the manuals I have and found this one :

Its the Extreme Flight Extra 300 58" model :

quote:

As with any high performance aerobatic aircraft, great care must be taken to avoid
excess speed. Excess speed could lead to control surface flutter and quite possibly the
complete destruction of your aircraft. Donít let this happen to you! Always have the
motor at idle when the airplane is pointed down and reserve full throttle for vertical
climbs. Make sure you have adequate mechanical advantage in your control linkage setup.
If you are unsure about this, have a more experienced flyer look over your set-up
before flying. Extreme Flight RC, Ltd. in no way warranties its aircraft against flutter.
As with all of our planes, we put the Extra through a rigorous flight testing regime and
have not experienced any control surface flutter. It is your responsibility to ensure the
airworthiness of your aircraft.

:unquote

Nigel

woodmangler 06-07-2015 04:31 PM


Originally Posted by solentlife (Post 975863)
Just a cut and paste from a manual ..... I was interested to look through all the manuals I have and found this one :

Its the Extreme Flight Extra 300 58" model :

quote:

As with any high performance aerobatic aircraft, great care must be taken to avoid
excess speed. Excess speed could lead to control surface flutter and quite possibly the
complete destruction of your aircraft. Donít let this happen to you! Always have the
motor at idle when the airplane is pointed down and reserve full throttle for vertical
climbs. Make sure you have adequate mechanical advantage in your control linkage setup.
If you are unsure about this, have a more experienced flyer look over your set-up
before flying. Extreme Flight RC, Ltd. in no way warranties its aircraft against flutter.
As with all of our planes, we put the Extra through a rigorous flight testing regime and
have not experienced any control surface flutter. It is your responsibility to ensure the
airworthiness of your aircraft.

:unquote

Nigel

High performance acrobatic aircraft?... surely the Apprentice does not come close to that description??

I can understand a plane reaching extreme speeds and things reaching their limit etc...

... but this is not the case with the Apprentice - I mean, I am barely cruising around, slow speed, babying the plane - after what happened to me you gotta know I was really taking it easy!

The little Pitts I was flying before it wandered off into no mans land was being flown literally as hard and fast as I could... full throttle, straight down spiraling so fast I could not make out heads or tails... I pushed that little plane hard, and not even the tiniest bit of flutter or complaints.

I guess it is hard for to imagine the Apprentice is being flown at it's limits, since I am flying it like a kite... slow, easy, gliding most of the time... so that only leaves something isn't working right.

Based on my very limited experience, that plane simply HAS to be able to do a LOT better than this!

solentlife 06-07-2015 05:10 PM

I should have posted better ....
The point was that even a purpose designed model for extreme 3D etc. is subject to its limits.
I was surprised to read it.

It was more post to show it happens ..... no reflection on you WM.

Nigel

Rodneh 06-07-2015 06:57 PM

The Apprentice's that I have examined have just two screws attaching the stab to the fuse and at best it is a rather loose fitting. By just putting a piece of scotch tape at each edge of the stab to fuse, you can firm up that joint so there is no play. This should help a lot in preventing the onslaught of flutter. You can still easily remove the tape should you have to replace or remove the stab.

fhhuber 06-07-2015 07:19 PM

Just 2 screws hold the tail on my Dynam Me-262.... and it handles 110mph +
(EPO foam model)

Filling a gap to eliminate slop is always a good idea. If it wobbles it will flutter.
Shouldn't be necessary on a modern molded foam model though.

Flexible material will eventually flutter. Just a question of what airspeed.

You can induce flutter with rapid control movements, aggravating the flex of the structure. That's what the video looked like. The gyro's excess gain started a rapid servo oscillation which made the tail-planes start flexing and it progressed from there. After flutter was initiated, the gyro was still trying to smooth the flight path and maintained the flutter.

The only way to stop flutter is slow down to a point where the surface isn't flexing.


All times are GMT +1. The time now is 03:58 PM.

Powered by: vBulletin
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.05526 seconds with 7 queries