HELP!! With Roban 700 Apache Tail

[DCORSAIR]

Thank you guys for all of your help. I am very nervous now about this motor. I don’t think it’s the motors fault. More likely mine somehow. But I may try a new motor. And, Deltadart, thank you so much for that video. That’s exactly what I needed. Unfortunately I actually would say that my belt was about that loose. But maybe not quite. But now I have something to go by. I know that everyone has different motors they are using but I believe motion RC’s website recommends the scorpion. I don’t want to break the bank but I want something reliable. Recommendations?

Which Scorpion you looking at?? two things I don't like about Scorpion, their mounting bolt pattern doesn't work with Roban motor mounts, you can only use 2 of the 4 mounting holes, and you have to oil Scorpion motor bearings ever so often recommended by Scorpion.

[F106DeltaDart]

I’ve had good luck with the Egodrift Scale Series motors. But they are a bit more pricey. They do tend to run cooler than the Scorpions as well. One thing I would recommend is installing the lower motor shaft support next time. Will help to relieve any bending moment on the shaft. All of the Superscale kits I’ve received from Motion have included these parts. Lower motor support bearing install video here (Although it is in German).

[Aces]

I don’t really have any in mind. Motion RC recommends the scorpion. I haven’t heard if the Egodrift. I will check those out.
and I will look into the extra motor brace. Seems like I remember something about that when I first got this thing. Almost 3 years ago now 🤪.

[Aces]

Is the 520kv the one to get if I purchased one of these? Also, are these the correct shaft size for the stock pinion?

https://www.egodrift.com/scale-collection-4035hs-520.html

[Aces]

Thank you for your response Birdman. I don’t think that I have much vibration. It seems to be pretty smooth overall. Someone suggested to try Re-orientating the Gyro to see if that makes a difference. And I may try some other tape. And I will have to see if there is any sort of comp setting like you describe.
A question for you guys is where is your opinion on your motor shaft? On my ally motor shaft opinion was at the very bottom of the shaft. There was not even a 16th of an inch sticking past the bottom of the shaft. So I’m not sure how I can stick the shaft into another bearing?
that is where the belt needed to be so that it did not ride up or down on the main pulley when it spins.

[PawPaw]

Look on the top and bottom edge of your belt…evidence of rubbing or fraying? Look at the edges of the frame where the large pulley is for the same thing. If your pinion was not set correctly on the shaft then the belt will rub on the frame. Belt should be centered on the large pulley when it rotates.

[DCORSAIR]

This makes me kind of worried on a couple of mine, my Magnum PI and OH-6 both 800 size don't have the bottom bearing support because I ran into the same problem as Aces, not enough of the shaft it sticking out to install the bottom bearing block, haven't broke any shafts but it makes me wonder if it just hasn't happen yet on mine. I know the Kontronik Pyro comes with the extra long shafts and the Hacker motors do, not sure on the Egodrift motors but they seem to be good motors, I see them listed at Scaleflying.de in Germany along with the Hacker motors, alot of over sea guys use the Kontronik Pyro series, they make a 45L ( 700-450kv long shaft) and 52L (700-520kv long shaft)

[PawPaw]

Spend it. More will come. 😎

[Aces]

There is absolutely no rubbing of the belt. I made absolutely sure that the position of the pinion would keep the belt centered on the main pulley. It seem to be extremely smooth and hovered around just great until this. I have not yet watched that video about how to install the extra bearing but I’m going to watch it and I think that I may try to go with a motor that has a longer shaft.
it’s still a strange situation though because I know that there are a lot of these mechanics out there flying this way. In fact the individual at motion RC who helped me quite a bit told me not to worry about that extra bearing. That it was very difficult to put in. But after this I think I am going to go far because there’s a whole Lotta money invested in this thing. And it’s not just the money. I’ve spent two years painting and detailing the few slides. One crash and it’s over.

[Aces]

Actually!! At $440 I’m not sure I need kontronik.
maybe I will have to have my dad turn me a shaft on his metal lathe.

[sfcfury]

That video in German is really good- you can turn the auto translate subtitles on as well. But it will show you belt tension, and belt placement/alignment (just as important), as well as the support bracket mounting. I drilled the holes in that little plate in front of the motor pinion for easier access to the set screws. I went a long time without the support bracket on the AH1 b/c it didn't ship with it.
I really like the Tengu motors... I have Scorpion and Tengu motors. On my 600 size, running 6S setup, I had a Scorpion 4025-730Kv that kept getting to 70c... so I switched to a Tengu 4025-750kv and it stays around 55-60c.

[sfcfury]

Actually!! At $440 I’m not sure I need kontronik.
maybe I will have to have my dad turn me a shaft on his metal lathe.

I'm really a fan of the scorpion Tribunus II ESC... I have tried, Castle, HobbyWing, Scoprion, and one Kontronik. I really like the slow start of the Tribunus, and I think the Tribunus V2 12S-130 will be my go to for the 700/800 birds. It's a little pricey compared to CC/HW but not as a bad as kontronik.

https://www.amainhobbies.com/scorpion-tribunus-v2-130a-12s-brushless-speed-controller-w-bec-scp-esc-0013/p-qqqeqzrqyb2xqctz

[Aces]

Yes great video. I didnt know about the subtitles but its pretty self explanatory. I knew thats what he was referring to at the end about drilling access holes because I had originally thought the same thing. But i just flipped the pinion and created a new flat. I will check out the Tengu motors as well. Do you know if they come with longer shafts? Looks like the shaft on my motor is roughly 33mm. So I need just a bit more.

[DCORSAIR]

Yes great video. I didnt know about the subtitles but its pretty self explanatory. I knew thats what he was referring to at the end about drilling access holes because I had originally thought the same thing. But i just flipped the pinion and created a new flat. I will check out the Tengu motors as well. Do you know if they come with longer shafts? Looks like the shaft on my motor is roughly 33mm. So I need just a bit more.

So you just said something in your remarks, you said you flipped the pinion and created a new flat spot?? So, do you think it is possible you went a little to much up on the shaft as for a flat spot or too deep?? I have done this many times but I just grind a slight flat spot just enough to hold the set screws. Not blaming you, just curious is all. Yes Kontronik is expensive, but you get what you pay for in my mind.

[sfcfury]

Yes seems like most of the motors have a choice of 2 or 3 shaft lengths.

[Aces]

I just watched the video on installing that extra bearing and it totally makes sense. I don’t know why they don’t recommend this. However there is no way that this motor will work with the shaft. So I either have to get a motor with a longer shaft or see if we can create our own shaft.
but for peace of mind I am definitely going to install that bearing.
Just wanted to show you some pictures of my motor shaft. I actually worked with my dad to create flats on the end of the motor shaft instead of up at the top of it the way it comes from the factory. Then I flipped the pinion around to make it easier to access the lock screws. But as you can see in the last photograph the shaft is right at the edge of opinion.

[Aces]

Sorry that last post is out of order. I’ve been going back-and-forth between my computer and my phone and I did not press post on that last one.
They say, the flats are just barely enough to hold the screw. So that’s not an issue. But I did wonder if somehow flipping the pinion and having it so far down on the shaft created more tension. But I don’t think so. The Pinyan teeth part would still be in the exact same position it was for the belt to ride in the middle of the gear.
adding the brace, if the south was long enough, would totally illuminate this. Assuming that you tighten the belt to the correct tension as well.
I actually just got through building the brace and getting it ready for the new motor/shaft. Easy Peezy lemon squeezy.

[sfcfury]

So you just said something in your remarks, you said you flipped the pinion and created a new flat spot?? So, do you think it is possible you went a little to much up on the shaft as for a flat spot or too deep?? I have done this many times but I just grind a slight flat spot just enough to hold the set screws. Not blaming you, just curious is all. Yes Kontronik is expensive, but you get what you pay for in my mind.

Yes...
If you did that both times... perhaps you went to deep; and without the support frame... just too much tension on the shaft. If you get a new shaft, flip it the other way and just drill some holes in that plate so you can tighten the set screws.

[DCORSAIR]

Ok, thank you for the pics, it broke where I thought it would, right at the edge of the flat spot, I have two of mine like that, that makes me nervous not being able to run that lower bearing brace, yeah it's easy to install once you figure out how it goes. Can't wait to see your Apache flying when your done with it.

[sfcfury]

Well if you do end up shopping around, here's a couple ideas...
Scorpion 4035-520

https://shop.mikadousa.com/Scorpion-HKIV-4035-520KV-F3C-Special_p_2593.html

Tengu 4035-520kv

https://www.egodrift.com/f3c-edition-4035ht-520kv-motor.html

The Scorpion has a 38mm shaft and is cheaper... and they are in the US so the motor would come quicker.
Then Tengu can pick a 38mm or 40mm shaft... more expensive and ships from overseas.