willyuk

As promised an update following my trial flights. Ordered an agenda today, so clearly I liked it. Not ordered the contra unit yet as the BJ xdrive "may" be available soon so I am waiting to see if that is a possibility.
Thanks for all the input, I appreciate you folks taking the time to help

Al.W

ltc

My Feedback: (3)

If you looking for a belt drive Contra unit, similar to the X drive, the Akiba Contra drive is available from Morris Hobbies in Japan
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They are very nice to work with; they have been able to get me a belt drive for my Fantasista 70 (50 products,. who designs the unit, wouldn't ship outside of Japan).

barnowljenx

Having just bought a second hand Agenda and separately a second hand Leomotion/CRS drive I've now managed to fly the combo. I was surprised to find that the aircraft pulled to the right on a vertical and required a fair bit of rudder to compensate. I'm running a Falcon 22x18 Front and 22x20 Rear. Has anybody else found this with the CRS drive in the Agenda?

underdw

My Feedback: (2)

Contra planes should pull straight - one of the primary motivations for having a contra.
I thought the Agenda was purpose-built for contra, but maybe the nose-ring of the plane has some right thrust built in - hard to measure, but I'd guess this is what is causing the pull.
Another possibility is a longitudinal warp in the fuse or fin.

rm

My Feedback: (27)

Should be easy enough to measure your thrust angle and see if you have the drive mounted correctly

barnowljenx

I should have said, the drive that was in it was a CRS and mine has just been bolted straight in using the same fitting. The airframe flew in a straight line before I bought it. The spinner is aligned with the nose ring in vertically and horizontally. I was wondering if anyone had experienced the same thing. As far as I can see, the geometry is exactly the same but the aircraft now pulls to the right. I thought that there was roughness on the front prop bearing and have returned the gearbox to the manufacturer for checking. I guess I need to wait to find out whether there is a problem with the gearbox I bought.

barnowljenx

I sent the gearbox back to the manufacturer, Ralph Schweizer Model Technik, and Ralph has identified some significant damage to the front prop drive shaft and bearings. This he is repairing. I begin to think that this damage might have resulted in improper torque sharing by the "differential" gearbox and may have caused the yaw to the right. I won't know for sure till I'get the gearbox back and fly it in the aircraft. I'll post when I've done that.

rm

My Feedback: (27)

My agenda I shimmed a little of the down thrust but the side thrust was pretty much on. That was after mounting the drive to match the nose ring.

f3a05

I seem to remember a story about Mr Schweizer seeing a photo posted somewhere, showing a model resting on its spinner (part of one of his contras), and emailing the owner,warning him not to do that!
Significant?

barnowljenx

Interesting! I have stored my Hacker C50-13XL powered birds resting on the spinner and those were soft-mounted using the same bobbins as for the CRS drive. I have not noticed any change of thrust line for either my Citrin or Toxiris but it bears consideration for all soft-mounted motors. Currently, it's not an issue as my Agenda is sitting on its bare nose ring. I will ask Ralph for his recommendation when I next email him.

David Bathe

A very pretty aeroplane... the look of which is holding up very well, even now that Bruckmann's Pandora has made almost everything else look redundant. The american designs are looking positively vintage by comparison.

mups53

My Feedback: (41)

Hey Guys
The newest Contra ready plane from BJ Craft is the Version 2 AJ Scheme Element.
Here's the new listing:

https://www.f3aunlimited.com/bj-craf...r-contra-setup
Thanks for your support.
Mike Mueller
F3A Unlimited

willyuk

Hi All, quick update on my Agenda build. I went with the Adverrun which arrived this week. The build has been going well thanks to Steve's build log and various other posts on the forum. I am on the last stage, fitting the motor is basically all that's left to do apart from all the checking and testing. Interestingly the latest version of the Adverrun has a greater distance from the back of the firewall to the spinner backplate. I did not have the potential issue that Steve had, I needed to make up an 8mm thick carbon/ply sandwich to get the correct spacing for the spinner. Also the prop fitting has changed and the rear prop is a single large nut now, not 4 bolts.
So I am looking forward to spring, good weather and the first flights.

Al.

shannah

My Feedback: (5)

Good to hear that things fit well. The new Adverrun drive looks like it has some advantages. You’ll enjoy the combination. Mine is still working flawlessly.

barnowljenx

Question for Steve Hannah.

Steve, did you mount your batteries so that their centre line is aligned with the cenrre of the motor shaft. I'd heard that having a Kg of Battery off centre from the prop shaft can lead to a slight disturbance in roll. I have to say that I provide all the disturbance in roll on my Agenda(!) but would be interested to hear of your experiences in this regard. If it is a significant issue, then I'll make up a new battery tray to raise the batteries from their current position which is well below the motor centreline.

Thanks.

Peter

shannah

My Feedback: (5)

Hi Peter,

No, I did not center the batteries on the prop shaft. I put my battery tray right on top of the landing gear mounting bulkheads, just like the other BJ Craft planes. I think it rolls nicely as it is. But, I don't think it would hurt anything if you raised them up to be inline with the prop/motor shaft. On the new Eternity bipe, B.J. suggests moving the battery up.

barnowljenx

Thank for that insight Steve.

Mark Hu

I fitted my new contra drive in agenda, 4600mah batteries， only 4463g, I was surprised.

wattsup

My Feedback: (1)

Hi Mark, I really like your new Contra-Drive, especially the weight of the unit. Could you tell me how much down thrust you have in the nose of your Agenda. Several of us have encountered "issues" with the down thrust of the Elements that came with a CD nose already (supposedly) built from the factory with the correct amount of down thrust. Looking forward to your response.

Mark Hu

Hello Wattsup, I set up my thrust refers to my wing, I have a full-moved elevator, so I fixed my wing as a reference, my elevator can be adjusted by my transmitter any time. I use laser to set the wing as 1deg like, install my contra with a scaled 3D printed fixture, and my contra rear support is adjustable，±1 deg， center is -1 deg. After a test flight, I adjust it. The final result is 0.9 deg down thrust. it mins different between contra drive and wing is 1.9deg. I even found that with different props size, you may need different down thrust. I try 23 inches prop once, I feel the plane climb a little bit, I need more down thrust with bigger props.

Set wing as ref

Center long line is -1 deg down thrust.

laser go through the install fixture.

install fixture

install fixture from the back.

all fixed ,Wait for the epoxy curing。


install the real contra drive.

fit in without back support.

Mark Hu

I marked on my fuselage and elevator for the 0 deg point when I set the wing as 1deg. I just measured my elevator and give you an idea. a little bit pull.