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Contra Rotating Propeller Drive for f3a 2m Pattern Planes

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Contra Rotating Propeller Drive for f3a 2m Pattern Planes

Old 11-26-2021, 02:39 PM
  #2001  
Brenner
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Hey John,

Try putting the pinion gear bolt back in and then loosen it up a few turns. Then tap on the head of the bolt with any handy tool. You should be able to knock the bronze insert free.

Brenner ...
Old 11-28-2021, 06:15 PM
  #2002  
ltc
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Hello
I have another quick prop question

I noticed that you can purchase 21” and 22” props with the same pitch front and rear
Is there an advantage or reason why you would want the same pitch front and rear?

I normally see different pitch between the two with the rear prop always having more pitch , like 20 front and 22 rear

As always, thank you
Old 11-28-2021, 06:46 PM
  #2003  
Brenner
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Originally Posted by ltc
Hello
I have another quick prop question

I noticed that you can purchase 21” and 22” props with the same pitch front and rear
Is there an advantage or reason why you would want the same pitch front and rear?

I normally see different pitch between the two with the rear prop always having more pitch , like 20 front and 22 rear

As always, thank you
When a Contra Drive is operating air is accelerated as it passes through the disk of the front prop so when this passes through the disk of the rear prop it is moving faster than it was when it was moving through the disk of the front prop. If the pitch of the rear prop is the same as the pitch of the front prop the rear prop must spin faster to match the torque from each prop. If the pilot wants a setup where both props spin at the same rpm and deliver the same power, then the pitch of the rear prop must be greater than the pitch of the front prop.

The V4 Contra Drive uses a planetary gearbox that automatically adjusts the speed of each prop so that the torque from each prop is equal and opposite, canceling each other out. This means that a V4 Contra Drive will automatically compensate for differences in the pitch of both props. If an Adverun style Contra Drive is used then no compensation is done. The setup will be more sensitive to the selection of prop pitch and prop diameter, and there will be prop effects that can be noticed by the pilot when the pilot transitions from full throttle to low throttle. For this reason, prop selection is more critical with an Adverun style Drive.

Brenner ...
Old 12-04-2021, 07:57 AM
  #2004  
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Question for Brenner: Will the V4 drive be offered with a motor suitable for 12S flight packs?
Old 12-04-2021, 08:14 AM
  #2005  
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Originally Posted by FLYERSG
Question for Brenner: Will the V4 drive be offered with a motor suitable for 12S flight packs?
Yes, there are two motors that are being considered. One is being offered for sale right now.

They are both Pyro 600 size motors, but they have been redesigned. The rear bearing has been upsized so that it is now the same size as the front bearings, and the front bearings are held in with a retainer clip. Internally these motors are designed with a threaded assembly that clamps the stator, which eliminates the need for the small cap-screw that retains the stator in the Pyro 600 motor. The windings are rated for 250C continuous and 300C intermittent, and the magnets are rated for 150C intermittent.

These motors also come with a redesigned collapsible collet for attaching the motor to the Drive. This collet clamps the motor shaft in two places, which guarantees perfect alignment between the motor and the Drive, even after severe prop strikes.

There is a 750 rpm/V motor that is available right now that matches the performance of the current 10s V4 Contra Drive, and there is an 812 rpm/V motor that is being tested for pilots who run the D3 rpm governing ESC. This motor is probably too powerful for use with a regular ESC but when used with a D3 ESC it gives the D3 lots of headroom that it can use to govern speed regardless of flight attitude or condition.

Anyone interested in the 750 rpm/V motor can get one through f3a Unlimited. However, you'll probably have to call Mike Mueller directly, because it's not listed on the website yet.

Brenner ...

Last edited by Brenner; 12-04-2021 at 08:18 AM.
Old 12-04-2021, 09:12 AM
  #2006  
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Thanks for the information. I also fly precision aerobatics with helicopters and run all of my Kontronik Kosmik and Jive Pro ESCs at 80% in Idle Up 2 to allow the governor to work so while I don't use the D3 ESC, I understand the need for its headroom. Might there be some advantage to using the 812kv motor with, for example, a Jive Pro and limit the throttle end point to provide for a prop RPM equivalent to a typical V4 10S setup? Then, on a very windy day, one would have the option of increasing the throttle end point as needed to gain a bit more speed. Just a thought.

Mike
Old 12-04-2021, 09:24 AM
  #2007  
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Originally Posted by FLYERSG
Thanks for the information. I also fly precision aerobatics with helicopters and run all of my Kontronik Kosmik and Jive Pro ESCs at 80% in Idle Up 2 to allow the governor to work so while I don't use the D3 ESC, I understand the need for its headroom. Might there be some advantage to using the 812kv motor with, for example, a Jive Pro and limit the throttle end point to provide for a prop RPM equivalent to a typical V4 10S setup? Then, on a very windy day, one would have the option of increasing the throttle end point as needed to gain a bit more speed. Just a thought.

Mike
The 812 motor that's being tested right now really has way too much power to be used without some sort of rpm limiter. My concern is that there's no practical way to guarantee that it wouldn't drive the motor way past it's rpm limit under certain flight conditions (for instance, diving at full throttle..) to recommend it's use without something like a D3 ESC, which has a specific rpm limiter built-in.

The 750 motor has more than enough power for anyone. I can say with good confidence that no one is going to complain about the power that's available with the 750 motor.

Brenner ...
Old 12-04-2021, 09:56 AM
  #2008  
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One more question. What capacity 12S flight pack do you recommend (I fly Masters)?
Old 12-04-2021, 11:12 AM
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Originally Posted by FLYERSG
One more question. What capacity 12S flight pack do you recommend (I fly Masters)?
Unfortunately, I don’t fly Masters so I can’t speak from personal experience. However, Tony Frackowiak has been having success with 4400 6s packs.

Brenner…
Old 12-05-2021, 10:33 AM
  #2010  
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Where can you use 12S batts in competition?
Old 12-05-2021, 12:18 PM
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Originally Posted by ini
Where can you use 12S batts in competition?
In the United States the AMA is going to allow 12s packs in pattern competition starting in 2022...

Brenner ...
Old 12-06-2021, 01:01 AM
  #2012  
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Good to have choices. Benefit of 12S over 10S seems to negligible. Same ESC, same size motor, maybe cable could be thinner.

At least in Europe you can find decent 5S 5Ah packs 570g/20oz. 6S packs are not any lighter.
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Old 12-06-2021, 03:07 AM
  #2013  
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Originally Posted by ini
Good to have choices. Benefit of 12S over 10S seems to negligible. Same ESC, same size motor, maybe cable could be thinner.

At least in Europe you can find decent 5S 5Ah packs 570g/20oz. 6S packs are not any lighter.
The primary benefit is that the system runs cooler. This is a benefit here in the United States because ambient temperatures regularly exceed 40C.

Brenner ...
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Old 01-20-2022, 03:25 PM
  #2014  
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Default Prop Recommendations

Hi everyone, I'm getting an Alchemy Bipe with a Contra V4 and was looking for prop recommendations. I was looking at the 23x20F (can't find it in stock ATM) 23x22R.
I've also read on this thread of people using 22x20F, 22x22R.
What setup do you guys recommend and what are some of the pros cons of different combinations.

Thanks
Old 01-20-2022, 03:34 PM
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Originally Posted by danielcaceres91
Hi everyone, I'm getting an Alchemy Bipe with a Contra V4 and was looking for prop recommendations. I was looking at the 23x20F (can't find it in stock ATM) 23x22R.
I've also read on this thread of people using 22x20F, 22x22R.
What setup do you guys recommend and what are some of the pros cons of different combinations.

Thanks
Hey Daniel,

Both setups are good. The 23" setup will give you more speed range and better vertical performance, and the 22" setup will pull less from your packs.

Brenner ...
Old 01-20-2022, 04:44 PM
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Originally Posted by Brenner
Hey Daniel,

Both setups are good. The 23" setup will give you more speed range and better vertical performance, and the 22" setup will pull less from your packs.

Brenner ...
Thanks Brenner, how much of a difference is there in battery consumption. What battery capacity are you using with 23" props
Thanks
Old 01-20-2022, 05:18 PM
  #2017  
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Originally Posted by danielcaceres91
Thanks Brenner, how much of a difference is there in battery consumption. What battery capacity are you using with 23" props
Thanks
With the 23" props I am using maybe 3700mah for P23 and about 4000mah for F23. However, the numbers you get will depend a lot on your flying style and your plane setup. The 22" props might be 200mah or so less.

Brenner ...
Old 02-20-2022, 12:51 AM
  #2018  
rm
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So if you have the older v4/pyro 600 mounted in your airframe, what exactly needs to be changed to mount the new motor with the new motor plate?

Does it require alteratation to the existing mount or just mount the new plate to the new motor and bolt it in?
Old 02-20-2022, 09:43 AM
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Originally Posted by rm
So if you have the older v4/pyro 600 mounted in your airframe, what exactly needs to be changed to mount the new motor with the new motor plate?

Does it require alteratation to the existing mount or just mount the new plate to the new motor and bolt it in?
it’s a “bolt-in” upgrade…
Old 02-28-2022, 10:35 AM
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Default Front Hub Removal

There seems to be a lot of up/down, left/right movement of the prop assembly in my V4 contra.....more than the normal amount resulting from the rubber shock mount. Consequently, I'm taking the drive apart to inspect it. How does one get the front hub off the drive? I removed the front prop but that front hub which sits right behind the front prop can't just be pulled off by hand. If I understand the diagram in the user's manual, the front hub is tightened down on a collet. I don't have any special puller tools to remove hardware that's sitting on a collet. Any ideas?

Mike
Old 02-28-2022, 12:50 PM
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Originally Posted by FLYERSG
There seems to be a lot of up/down, left/right movement of the prop assembly in my V4 contra.....more than the normal amount resulting from the rubber shock mount. Consequently, I'm taking the drive apart to inspect it. How does one get the front hub off the drive? I removed the front prop but that front hub which sits right behind the front prop can't just be pulled off by hand. If I understand the diagram in the user's manual, the front hub is tightened down on a collet. I don't have any special puller tools to remove hardware that's sitting on a collet. Any ideas?

Mike
If you bought the drive new, you would have gotten a brass hub puller. It is a nut with outer extended threads and treads on the inside, You screw it onto the shaft and tighten. it threads into the hub. It is only a friction fit, and this will pop the collet free from the shaft. If you don't have a puller, you can carefully apply equal pressure on both sides of the outer hub by prying against the rear spinner. Be very careful, you don't want to bend anything.
If someone else has done it without the puller please chime in.

Bill
Old 02-28-2022, 01:01 PM
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Originally Posted by Bubblehead575
If you bought the drive new, you would have gotten a brass hub puller. It is a nut with outer extended threads and treads on the inside, You screw it onto the shaft and tighten. it threads into the hub. It is only a friction fit, and this will pop the collet free from the shaft. If you don't have a puller, you can carefully apply equal pressure on both sides of the outer hub by prying against the rear spinner. Be very careful, you don't want to bend anything.
If someone else has done it without the puller please chime in.

Bill
Thanks so much! I do have that threaaded brass piece you mentioned but couldn't remember what it was for. It has been quite some time since I installed the drive. Thanks again.

Mike
Old 06-09-2022, 09:46 AM
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Hi
Hi, I'm trying to unmount the contra v4. I've taken out the labyrinth seal and bolted in the pinion gear bolt to push the collet but it's not doing anything (it bottoms out). I've tried a longer screw that bottoms out but have applied reasonable force but it won't come out. Any suggestions
Old 06-09-2022, 10:50 AM
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If it is the newer style collet that extends back to the front bearing of the motor, it is not intended to be removed as you described. I believe the motor should be removed from the plane and collet heated so it can be pulled off.

Originally Posted by danielcaceres91
Hi
Hi, I'm trying to unmount the contra v4. I've taken out the labyrinth seal and bolted in the pinion gear bolt to push the collet but it's not doing anything (it bottoms out). I've tried a longer screw that bottoms out but have applied reasonable force but it won't come out. Any suggestions
Old 06-09-2022, 12:14 PM
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Originally Posted by DaveL322
If it is the newer style collet that extends back to the front bearing of the motor, it is not intended to be removed as you described. I believe the motor should be removed from the plane and collet heated so it can be pulled off.
There is no need to heat the collapsible collet. Just get a longer bolt. I actually use a 25mm set screw. It works great.

Brenner…

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