obi1

My Feedback: (1)

Hey Brenner,

Yes agreed , fantastic install , complements of Brian I might add, to be fair he is a master at this type of work.
Just hoping the weather calms a little to enjoy it!!

Rgds

John

Angus Balfour

Looks like it needs some more carbon to me.

John, there is a little window tomorrow night for flying between last weekends gales and the ones due this weekend. Get charging boyo!

Bob Hartwig

Great stuff guys, I wanna play again.

gmr1948

Brenner

Now that the tentative delivery date of late May has passed, do you have a new estimate as to when the contra drive unit should arrive?

Thanks,
Gary

Brenner

Hey Gary,

Right now we have all of our Contra parts except the front and rear spinners. However, unfortunately for us the CNC lathe that we were scheduled on got preempted by a rush job for the military and we didn't have much say in the matter. (something about being a country at war ...)

Anyhow, we are now back on schedule, (albeit, somewhat revised ...) and we have an expected delivery date for finished anodized parts on Friday June 17th, which means that I should be able to get your Drive in the mail on Saturday June 18th.

Keep in mind that we can change your color up until the time we take the spinner parts in for anodizing, which should be the 16th of June.

Brenner ...

Angus Balfour

A quick update. Team Ireland had a practice session yesterday and all the contras were going great. Everyone that saw them seemed to be very impressed. I think we are all using the 10.15 gears and mixed props at the moment. I'm going to try the two 22X20's and 9.89 gears over the coming weeks to try and get a "high wind" setup.

Angus

Brenner

I've been using the 22x20's and the 9.89:1 gearset with Thunder Power 65C G6 packs and a Hacker C50-14XL, and for windy days with 90 degree cross wind (like at Chicago this last weekend ..) the speed is pretty good, but on one flight I flew quite a ways out with really big maneuvers, and I ran out of battery when setting up for landing, and I had to come in deadstick.

When I charged my pack, I put more than 4800 mah back into the packs, so this setup works, but it pushes your packs to the limit. However, I think I would have probably been fine with the new Thunder Power 25C packs, and I'm going to get a set of these and see how they work. By way of reference, I flew my other rounds with 85% ATV, and I was putting about 4100 mah back into the packs, and the speed was still fine.

Brenner ...

TonyF

My Feedback: (92)

I use the set-up Brenner mentioned in the Osiris. But I am using a Neu motor. And I have cut 1/4" off each tip of each prop. I fly about as big and fast as they come and in a Masters pattern, even in wind, I have never put in more then 4200. Usually it's 3,800, 3900. It is a bit higher then a single prop, but oh, the benefits!

I am going to try the 22x18 on the front again. I tried it a while back and didn't think it offered any advantages, but I think I need to try it again.

jarvis johnson

My Feedback: (15)

Hey Tony
Is that the small Osiris, or are you test the Big 2 meter?

Angus Balfour

I did some experiementation today with props. All were on the 10.15 gear set:

22X18 front and rear. Nice slow pace and slightly more braking than mixed props. Very high pitched "whiney" sound which I didn't like.

Mixed props. Awesome all round set up. Gorgeous sound, totally different to the 22X18's.

22X20 front and rear. Bloody ballistic! Plenty of speed for even the windiest conditions that we would get asked to fly in. Nice quiet set up, different sound to the above two set-ups again, but nice. It was much more noticeable that the batteries were beginning to fall away towards the end of the flight (was flown in a fairly stiff 90 degree cross wind). With the new TP 5000 65C this would be a truely magnificent set up for high winds.

Angus

Brenner

Here are some pictures of Contra setups here in the American Midwest, and one picture of Dmitry Zagitov's setup in Russia...

servari

Hey brenner,

Here are some pictures from french Nat, and contra-drive*

Vincent ...

papaone

Hello Vince

Congratulations for your great championship.
Do you think it's easier with contrarotating prop ?
Claude

servari

Hello Claude,

Thank you for your encouragement !

Is a mustang easier to drive than a 2 CV ? Hard to tell !
All I can say is that the mustang is more efficient.

Vincent ...

bem

My Feedback: (1)

Hi,

I'm just curious - do You think the advantage with contra rotation props is so big that top fliers need to use it to be able to stay at the top?
This unitis a very nice thing and it looks so cool and seems to be some clear advantages but the added cost of $1200-1300(for Brenner's unit) will not help to broaden the baseof peoplewant to get more serious into F3A flying I'm afraid. But maybe there will be more manufacturers of contra rotationg props units in the future and cost will hopefully get down a little.
The spinner/props looks rather fragile and a light prop strike is out of the question I suppose.

Anyone know what contra rotation props unit Sebastiano Silvestri use on hisWind S Pro "all composite", seen in the picture in link below:
http://www.highalpha.org/forum/download/file.php?id=14857&mode=view


/Bo

Spark09

He uses the E-Factor contra drive made by Mr. Ramel

serious power

Hi,
Just a few pointers;
The props are no more fragile than any other carbon props.
Brenners drive has a clutch built in that will slip in the event of a strike so the props do not break.
Seba's unit is now down to 2500 Euros thats $3500.00 .
For the $1200 you are getting 2 props at $100 each and the spinner at say a value of $100.
Then you can buy a motor only (no gear box) saving $300.
It is a net increase of $700.00 approx over a standard good quality motor/prop spinner set up.
There are gear and prop options with Brenners that makes it a for more adaptable unit to your model choice and or the weather thats prevailing.

bem

My Feedback: (1)

Hi,

Then Mr Brenner's contra drive unit is a bargain (compared toa E-Factor unit -I did not imagine other unit had such a high price tag).
Hats of to Mr Brenner for developing this unit and offer it to those that want to use contra rotation props.
Hope there will be no unexpected problems with the unit when there are more hours on them.

I would love to see a video of some of the planes that fly with Mr Brenner's unit - is it a video somehere?

/Bo

Brenner

The primary problem with the cost right now is the small batch size for manufacturing. The cost to manufacture 50 sets of CNCed parts is three times the cost to manufacture 500 sets of CNCed parts. If the demand is only fifty units a year or less, then the cost will probably have to stay high, but if the demand increases, then the cost can come down proportionally.

As far as advantages are concerned, I think that the top flyers stand to benefit the most because the point spread amongst the top flyers is so small, but I also think that the benefits spread to all classes of flyers as well. Based on the way I was scoring about a year aga, I think that I have gained about 50 points flying in the USA Masters class. Although, this is a hard thing to judge, because it assumes that my skills haven't improved, and the skills of others haven't improved either.

Brenner ...

Dsnow

Hi Brenner, I was able to get my other Spark flying with the Neu motor and RASA 20.5x14 combo, 20 flights now and not completely trimmed out but just about there, and it's flying well and I hope to have both planes flying the remainder of the season. The planes are very similar in roll rates, elevator and rudder response and vertical speed but very different in other ways. On vertical up lines there is very little correction needed except for wind with the contra but the single prop setup I'm constantly making small adjustments to maintain the straight line, stall turns are very easy with the contra - essentially hit the rudder at the right time - while the single prop setup I need to work the ailerons to maintain the wings in the proper alignment, snaps are much easier to setup with the contra - the snap speed is essentially the same both directions while the single prop setup the speeds are very different, spin entries are much easier with the contra - maintain flight path with essentially rudder only and feed elevator until stalled but the single prop setup needed more inputs with ailerons and rudder to maintain the flight path. I'm not saying that the Spark with the single prop is not flying well, it's actually flying very nicely, it's just that the contra Spark is easier to fly.

Dave

TonyF

My Feedback: (92)

Dave's comments are very similar to what I have seen flying the Contra unit in my Onas. It flew well with the single prop set-up, but it's better with the Contra. To decide it it is necessary to win at a top level, well, that's hard to say. I think most would say electric flies better then glow, but electric has yet to win the World's. But I do feel that as more top fliers try it, you will see more Contra's in competition.

wattsup

My Feedback: (1)

I'd like for someone to follow-up with an answer to a statement made earlier in this thread by "serious power". Are you saying or leading us to believe that as a result of the Contra drive unit having a built-in clutch, that a prop strike won't result in any damage to the tips of a carbon prop? I guess once again, you better show me! Perhaps this is in the realm of 600+ charges claimed to exist with the new G6 Thunder Power batteries currently available that you will be able to charge at excessive rates. All I am seeking is the truth______Everette

serious power

Hi,
Yes a clutch is in there - believe it or not.
Yes we have had a few heavy prop strikes, not on tarmac or concrete, with no prop damage.
Prop strikes on tarmac etc are rare anyway.
Next time you are in Ireland I would be happy to demonstrate.

Brian

wattsup

My Feedback: (1)

IMHO, you or anyone else using a carbon prop or any kind of prop on this unit or any combination will eventually have a problem due to the minimal ground clearance involved with ALL electric pattern planes. Unless you are running 19x12E props. Now the odds of this NOT happening are about a good as my visit to Ireland for a demonstration! Think about my question when you do have this experience! Regards, Everette

serious power

Hi Everette,
This is not the thread for this ,however;
If the problem,percieved or real, is ground clearence then solve the problem. It's easy !!
Some people tolerate poor clearence and I do not know why.
In 5 seasons/2000+ E flights I have not even chipped a prop.

Brian