Brenner

Hey Bem,

The current version is version 3. This version is proving to pretty reliable. Gernot Bruckman put 800 plus flights on his drive before we asked for it back, and when we tore it down it looked good enough inside to probably put up several hundred more flights at least.

Dmitry Zagitov recently told me that he has upwards of 1200 flights on one of his Drives, but I don't know if that includes any parts changes or not. Also, I think that Tony Frackowiak out in California regularly gets 600 plus flights on his Drives.

I personally fly mine for a season, which is 500 to 600 flights, and then I swap it out for a new Drive for the next season. (One of the benefits of being a manufacturer..)

I think the objective for any pilot is to fly the current season trouble free, and then provide whatever service is required to get the same reliability for the coming season. So, with this in mind, and based on real world performance, this is what I recommend with regards to usage and service:

1/.. 3cc of grease through the center of the Drive shaft every 50 to 100 flights. (Rheolube 374A from Nye Lubricants)
2/.. Replace all three planet gear bearings every 500 flights
3/.. Replace the ring gear, the planet gears, the pinion gear assembly, and the pinion gear bearings every 500 flights
4/.. Replace the rear hub front and rear bearings every 1000 flights
5/.. Replace the gearcase main bearings every 1000 flights
6/.. Replace the clutch plates every 1000 flights

I think if this service schedule is followed, it's reasonable to expect to be able to keep flying trouble free indefinitely.

However, this doesn't cover what the motor may require, so motor bearings will also need to be replaced on a regular interval as well.

As far as weight is concerned, a Contra Drive mated with a Neu f3a motor is 700g, excluding any mounting plates. So comparing this with the Q80 14SX qt 528g and an 82mm Tru-Turn spinner at 60g this means that the Hacker is lighter by:

700 - (528 + 60) = 112g

These weights also don't include props. The Contra Drive requires two props at 50g each, whereas the Q80 can use a 45g Falcon prop, so this is another 55g advantage for the Hacker motor.

The total weight advantage is 112 + 55 = 167g, which is impressive for the Hacker. My congratulations to Hacker for being able to produce such a light motor.

The Neu f3a-1 motor without the gearbox, and with the straight cut rotor spline is still available. It can be purchased directly from Neu motors, or from www.f3aunlimited.com.

I haven't flown a Mythos S Pro yet myself, but I know of several people who have, and they all say that it flies very well with the Contra Drive.

I believe that the fuselage is very similar to the Wind S Pro, and the installation of a Contra Drive in the Wind S Pro is very straight forward. The only thing that's important to watch for is that that the motor is set with zero right thrust, and 1 degree of downthrust relative to the wing.

I would definitely recommend the Neu f3a-1 Contra motor from f3aunlimited, and our new 20" set of props. The performance of these props is excellent, and they are also very quiet. (measured at 87 db at WC in SA..)

The Thunderpower Pro Lite 25C packs work very well with the Contra Drive. I have also been using 35C Power Unlimited packs from f3a unlimited, which are almost as light as the Thunderpower packs, and the performance is phenomenal.

Brenner ...

bem

My Feedback: (1)

Brenner,
Thanks for the detalied information. Sounds good, the only slight disadvantage is the weight penalty in my view.
I use Hacker/Jeti Master Mezon ESC now and do You know if Neu F3A-1 motor works with that ESC without any trouble?
Master Mezon and Hacker motor is no trouble since I use that combination today.
/Bo

Brenner

Hey Bem,

The Jeti Mezon, is an excellent controller for the Contra. It's what I use. I use the BEC version with a 250mah pack as backup that's kept charged by the BEC.

The weight difference is significant, but keep in mind that this is only when compared with the Hacker Q80 14SX motor. 528g is extraordinarily light, and a significant accomplish by Hacker in my view. Most other motors are going to be 100g or so heavier.

Getting a motor that light is an interesting development. Obviously, with today's battery technology, having an extra 100g to play with gives the pilot fungible design margin that can be used to increase the C rating on battery packs, use larger packs, etc.

However, looking forward into the future I think it's reasonable to expect that the next generation of battery technology will probably provide similar benefits, so the question then is, do we want to use extra weight margin to make more power and energy available, (not quite the same things ..) or do we want to make airframes lighter?

I'm of the opinion that the truth is going to somewhere in the middle. I think that power systems will become more powerful, and more energy will become available to fly the unknowns in f3a, but lighter airframes will also be important as well, because lighter planes fly better. However, a lighter plane will have better vertical performance, and will have slower downlines, but both of these things can also be accomplished with a Contra Drive.

Another possibility is that planes can get bigger instead of getting lighter, which accomplishes the same thing, but with the added benefit that the plane will present better.

I'm thinking that when the next generation of battery technology becomes available, power requirements will go from about 2750W to 3750W, and mah ratings will go from 5000mah to 6500mah. (Just educated guesses on my part..) And then more than likely, planes will get bigger to absorb the additional power, and biplanes seem to be an obvious way to increase airframe size without violating the 2m size limit. (Kinda like what Bret Wickizer flew at the last WC..)

If any of this thinking has merit, (debatable at best..) then motors will have to get heavier in order to deliver more power, so the question becomes, which type of motor technology scales better when power output is increased, inrunner technology or outrunner technology.

Brenner ...

bem

My Feedback: (1)

Hi,
First step completed: Sebart MythoS Pro ordered today. I was able to find one in stock here in Europe where I live so it should arrive at my home within 1 week or so.
Next step: to descide what motor to use is not yet finally descided but Hacker Q80 14SX or Neu F3A-1 motor with contra drive is today on top of the list.

/Bo

grotow

Brenner,

With the exception of the planet gear bearings, do you recommend returning the drive for installation of other bearings?

Gary

Brenner

Hey Gary,

all of the bearings are user serviceable except the large diameter rear bearings in the gearcase. These require special tools and a fixture to remove them and to reinstall them,

The pinion gear bearings are user serviceable, but they are tough to get out

The best way to replace these bearings is the just send the gearcase back to us, and let us do it. We don't charge labor for replacing bearings. You can even send us new bearings as well, and we can install them for you.

Brenner ...

Jason Arnold

Hi Brenner,

Are you around at the moment? Not sure my e-mails are getting through to you or not....

Cheers,
Jason.

Brenner

Hey Jason,

I'm around. It's just that I'm a little swamped with day job stuff. I'll have to wait until I get home this evening before I can give a proper response to your emails.

Brenner ...

Jason Arnold

No worries Brenner, fully understand on the day job mate. ;-)

Dad machined the rear driveshaft bearing housing as suggested. All fits real nice!

Having now pulled down my drive, I'm even more impressed with the level of Engineering.

Cheers,
Jason.

Jason Arnold

Hi Brenner,

Do you have any inside information on the Plettenberg motor under development for your Contra Drive?

Cheers,
Jason.

Brenner

Hey Jason,

Nothing yet. I'll let you know when I get any news.

Brenner ...

can773

My Feedback: (1)

When I asked at the end of January they were still working on it. It's a Dinator series with a custom shaft. Will see if I can find out when they will release it.

Chad

Jason Arnold

Thanks Chad,

Good to be back home? ;-)

Cheers,
Jason.

can773

My Feedback: (1)

Not really, still snow here!

This is the response from Pletty. Could be a while yet I am sure it is Rannethauser (sp?) running it, same guy who flew the first one at the WC.

Jason Arnold

Thanks for following this up Chad. I'm sure it will be a well developed solution once it is released and will give Contra users another option regarding motor.

BTW, we have humidity and thunderstorms here now....

Cheers,
Jason.

mups53

My Feedback: (41)

Hello everyone. Just wanted to let you know the full array of Contra Rotating Drive products as well as the motors and mounts are for sale on the F3Aunlimited site.
We are partnering with Brenner and Mike to distribute and provide customer service.
http://www.f3aunlimited.com/webstore...8f413055f1cfd9
Thanks, Mike Mueller

Niall

Flew the Acuracy today for the first time. Very happy so far, Very stable and goes great with the Contra..

Malcolm H

Very nice Niall,

Is that the standard Oxai landing gear extended or something else?

Malcolm

Niall

Hi Malcolm,
These are Oxai legs, not the same as the Asyuler set. Plenty of clearance.

Niall

Malcolm H

Thanks Niall,

Malcolm

Jason Arnold

Good move guys. Allows Brenner & the guys to concentrate on development.

Cheers,
Jason.

blake26m

Well done Niall, Looking forward to seeing it fly!

serious power

Hi,
Here is another model for the Contra stable.
It's by Gernot Bruckmann in collaboration with Andrew Jeskey apparently.

Interesting to see they have decided to go with the rudder flare.

Brian

serious power

Hi,
It seems that the Contra continues to gain traction , if you'll excuse the pun.
See photo taken from facebook.

Brian

mups53

My Feedback: (41)

This is the front end of a BJ Craft Prolog We can covert any in stock plane to fit a Contra for a nominal added cost. Call for pricing on this service.
Thanks, Mike Mueller