Malcolm H

Yes they do!

I see it's Ulsamer's model so he should know a thing or two about props. What's very interesting is the pitch difference between the front and rear it looks like 22" rear and 14" or maybe 17" front.

Malcolm

serious power

Hi Malcolm,
I think it's got 22x21 front and 22x22 rear.

Brian

Malcolm H

I think you are right Brian

M

SAB

Here's a Picture from one of the WC Blogs of Germanys Philp Rannetshausers' Contra powerd Axiomes - looks like no additional aerodynamic additions either.

Steve

Brenner

We have three sponsored pilots at the Worlds, Marcus Zeiner (AUSTRIA), Philip Rannetshauser (GER), and Joseph Sczur (USA).

I believe that Philip is also using a prototype Pletenburg motor as well with one of his Contras.

Brenner ...

rgreen24

My Feedback: (6)

Brenner, any further info about the plettenburg prototype motor?

Brenner

Not much info at this time. It's still being developed, so everything is subject to change right now.

Brenner...

OhD

I thought I had put this out of my mind, but now I am all charged up. I'm going to check it out today to see how easy it will be to retrofit. It must be working well if he made it to the semi's. Thank's for passing this on.

Jim O

bem

My Feedback: (1)

Hi,

Maybe mentioned before but Sebart has info on their homepage on new contra drive unit (I have not seen info on that before):

http://www.sebart.it/img-F3A/coaxial...ial-drive.html

/Bo

Doug Cronkhite

My Feedback: (34)

Seba's airplane had an odd cavitation sound to it. Do all of the contras sound like this? I haven't heard one of Brenner's fly yet.

serious power

Hi Doug,
Yes and no .
It depends on what props you use.
If the pitch is the same on both it's at it's worst.
With a 2" difference ,front less than rear, it changes completely.
There is still a rhythm but it is very akin to a flat four boxer engine type sound - different but quite pleasing.
Different relative diameters also play a role.
In this part of the world we all use 18" front and 20" rear - would not change the sound if you paid us.

Brian

bem

My Feedback: (1)

I heard Brenners Contra drives in July this summer at a competition, one in a Wind S Pro (from Finland) with carbon props and one in an Angels Shadow (from Denmark) with APC props and it was clearly a "different" sound compared to single prop F3A planes. Not ugly sound but not pleasing sound to the ear either I would say. It was some wof-wof-wof sound in the air. Hard to describe and I have never heard any similar.

/Bo

Doug Cronkhite

My Feedback: (34)

I'd love to try one for sure.. Maybe on my 2nd BiSide

Brenner

A new piece of information;

Philip Rannetshauser flew a Contra powered Axiome to a 2nd place (junior..) finish at the Worlds in SA using our latest APC clone carbon fiber props, and Christian Rannetshauser, German team manager is reporting that Philip's setup was measuring 88 db at the official sound check before each flight. Christian says that these measurements were at maximum power, and the throttle curve wasn't ATVed back.

These props have similar diameter and pitch to the APC Contra props, except that the airfoil is thicker in the inside portion of the blade, and the blades are narrower as well. Also, they only weigh 50g each. They are also noticeably quieter in the air compared with our first generation props, and there is no syncopating rhythm sound either.

These props also perform well too. The performance is similar to a 22x22 rear with a 22x20 front, except that I think the vertical performance is actually better. However, this is with a low drag Wind S Pro. The performance will obviously change with different airframes.

Brenner ...

Dansy

My Feedback: (53)

AHAH your re-written history....."2nd place finish at the Worlds in SA" ?? Did you forget a 7 like in 27 Still a superb system.....I might try it next year.

Brenner

Sorry, I meant 2nd Junior. My bad..

Dansy

My Feedback: (53)

I didn't look at the junior....my bad...still a wonderful performance.

patternflyer1

My Feedback: (11)

If these are the props you flew at the nats, i was impressed with the speed and power. One thing i hadn't been fully impressed with before. Nice addition for those who do want more speed. Especially in the wind.

Chris

Brenner

Hey Chris,

Yes, these are the props I flew at the Nats.

Brenner ...

PeterP

Hi Brenner,

when will these be available?

Brenner

Hey Peter,

We are shipping these props right now, but currently we are struggling a little to keep up with demand. Consequently there's about a two week lead time for delivery.

Brenner ...

flyncajun

I have to say the contra`s did great in the winds and the sound was much better in the air.
looking forward to getting the new plane done, and testing mine. If Scott lets me fly it


Bryan

OhD

Well there are at least two Axiomes with Contra Drives now. I finally got mine in the air yesterday. I was ready to sell the whole thing until I figured out I still had a throttle to rudder mix, but once I deleted that I was convinced that I'll probably never build another pattern plane without a Contra. I still have some cg and fine trimming work but it looks like a keeper now.

I did fly Brenner's new props and they sounded great and pulled just fine. I'll have to take a close look at the data but It looked like I was pulling 77 Amps at full throttle on the ground which should be right around 3000 Watts.


Jim O

Brenner

Hey Jim,

That's great to hear! I'm really glad that you're having good success with your setup.

It looks like the Axiome is another great platform for the Contra. Based on the feedback that I've received so far, pilots have reported good results with the following airframes:

Axiome,
Wind S Pro
Oxai Hera S
Oxai Citron
Valiant
Sensation
Visa

All of these planes have flown well without modifications, and I'm sure that here are others that I can't recall, and the list is still growing. Also, this is not to say that there aren't many other planes that also fly well with modifications. I think that pretty much any plane can be made to fly well with simple mods.

Brenner ...

OhD

You can add the Mythos to your list. We had three planes flying yesterday and they all had Contras; Axiome, Mythos, and Visa. I didn't mention it but I installed the Contra without disturbing the original Neu/gearbox installation. This meant everything had to go in from the front. Figure that one out. In addition to being heavier, the Contra/Neu assembly must be located further forward so you need room to place the battery further aft to get the cg right.

Jim O