Small problem with AXI5345/14 setup in EF extra 88"

[amigob]

Hi all

I have a small problem with the setup of mij EF extra 88
- AXI5345/14
- Jeti spin 99 Opto
- Hyperion G3 2 X 5S 5000mAh

First test : I did with a Menz 22x10
- got max 80A
- 10.5 kg ( oeps 23 lbs ) thrust.

second test I switched to Menz 23 x 10
- 110 A
- 28.5lbs thrust

power enough for the 16.5 lbs extra
but I got an odd sound from the engine when I varry the throttle position
arround the 40% throttle position. In al other postions this problem doesn't
occure.

I made a video, in the begin the problem occurs ( click )
http://dc152.4shared.com/img/104326746/66ae98e6/P5090312.AVI (http://www.4shared.com/file/104326746/66ae98e6/P5090312.html)

Any body an idea wat is going on, I tried with the following timings 24 and 20 degrees.

Bart

[Goinav8n]

Hi Bart

I would put it on low timing and try again. This should solve it. Nice setup. It should be a ball to fly.

Jeff

[go-flight]

Judging from the video I would say you should experiment with the acceleration delay feature of the Spin. What happens is that the controller wants to spool up the motor faster than the torque of the motor is capable of and then the controller looses the timing. It will cause a stutter.

Pending more tests, you may find that you will only see this in the very beginning of the flight when the voltage on the G3 pack is at it's highest and just adapt to that. However, setting the delay up one increment will probably prevent it in all cases.

If you haven't flown it yet - have a great maiden!

[amigob]

I already tried to change the acceleration, was 1 second, when I switched to 3 seconds it almost disappeared completely. But 3 seconds was way to much.

Goinav8n
How low can I go, because they say that normally it will need 24 degrees.

The maiden is still pending, waiting for the extension cords for all the servos :-(
I talked today to a fellow model flyer, and he told me that switching to a lighter prop will also help to over come this problem.

Bart,

[go-flight]

In my experience, you cannot get ridd of it by changing timing.

If you can't find an acceptable acc. delay with this prop, then prop down. By propping down, the motor will have less of a hard time to spool up and torque wont run out. Have you considered using a lighter electro prop instead of a gas prop?

[amigob]

When it solves the problem, of course.

I already looked at the Xoar 23x10 ( maybe 24x10 ), but I don't know how they are compared to the menz props and a 23x12 is not available.
I don't like the APC's I have a 15x8 on my EF 58" extra and it has problems
with the 1.6 kW that I put in it.

So wood or carbon I like.

Mejzlik
22"x12"E think this is to small ?
next one is
24"x10"E think this is to big ?

problem is that the Xoar's need to come from a long way, so a reasonable
estimation is needed. Want to order the Xoar's also for my 58"

Bart,

[Goinav8n]

Bart

On my last 2 outrunners with high power I had to use the lowest timing avalible.

A good suggestion was to try propping down. I know you said you didnt like the APC props but try it and see which sizes works best. Thats the simplest solution

Jeff

[Ron101]

I have this motor for a gaint scale P-51..
I've done tons of research on this motor.. I find that this is a common problem with this motor. I feel that the higher KV is more of a speed motor than a 3D type motor... I'll bet you prop down it goes away

the suggested prop for this motor is a 21x14 APC
that's what I'm going to try with my P-51.. I know the watts will be lower
but I want speed because it's a warbird.. so the high RPM will be great

guys running big props on the lower KV AXI 5345 16 and 18 are not having this problem... so it leads me too the KV

I have an Spin 200 for mine.. so I'll see what happens when mine is ready

hope you get it worked out

Ron

[bluelevel]

Hi Bart,

don't worry, I know this sound very well from my Hangar 9 Sundowner which I've flown with an Axi 5330/24. It has absolutely nothing to do with a synchronisation loss between the ESC and the motor! In that case you'd hear a screeching noise, which would only occur at high RPMs and fast acceleration. Furthermore would you encounter a severe and immediate power loss. Your sound comes from a vibrating cowling caused by an unbalanced and too heavy gas prop and/or a weak motor mount.

If you want to keep your Menz props check their balance and also try to beef up your motor mount if possible.

However, I'd not recommend using a heavy Menz prop which is mainly designed for gas engines. If you want to stick to wood props I'd recommend the new "Metts" line, which is distributed by Austrian dealer Lindinger. They offer a 22x10 and a 23x8 which would fit your Axi (see link (http://shop.lindinger.at/index.php?cPath=1084_1473_1127&sort=4a&filter_id=240) ). If you want to use a carbon prop instead, my best experience is the Mejzlik Electro prop (see link (http://shop.lindinger.at/index.php?cPath=1084_1473_1127&sort=4a&filter_id=139) ). Best choice for your motor and plane would be the 20x11 either with normal or wide blades (the wide blades might easily exceed the ampere limit of your Spin 99)!!!

Thomas

[amigob]

Thank you all, I am first going to try a electro prop,

The engine mount is made and designed by me.
As far as I can judge, it was very rigid

It is a sandwich construction, with wood, depron and aramide on the outside and a number of layers of glass on the inside.
http://img89.imageshack.us/img89/1691/motorsteun1.th.jpg (http://img89.imageshack.us/my.php?image=motorsteun1.jpg)

http://img89.imageshack.us/img89/3233/motorsteun3.th.jpg (http://img89.imageshack.us/my.php?image=motorsteun3.jpg)

http://img89.imageshack.us/img89/9611/motorsteun4.th.jpg (http://img89.imageshack.us/my.php?image=motorsteun4.jpg)

Bart

[amigob]

AXI replaced the engine, and everything works fine now

Bart,

[staggerwing]

Interesting thread---From my expirence if it weren't for user feedback on this site, the real problems/challenges w/ RC products, thier manufacturers, & distributors would never be revealed to its customers.

[amigob]

I see now that I didn't post my latest setup here, This setup with the old motor had still the problem, with new motor problem was gone, only change to new 5345/14

Hacker A60 motormount
Xoar 23x10
Max current 105 A
Static trust 13 kg 28.5 lbs ( measured with old engine )
Still G3 10s 5000mAh

I am going to fly this setup for a while. And if this holds up I will go to Xoar 24x10

Bart ,