Go Back  RCU Forums > Electric Aircraft Universe > Electric Pattern Aircraft
 Contra Rotating Propeller Drive for f3a 2m Pattern Planes >

Contra Rotating Propeller Drive for f3a 2m Pattern Planes

Notices
Electric Pattern Aircraft Discuss epowered pattern aircraft in this forum

Contra Rotating Propeller Drive for f3a 2m Pattern Planes

Old 11-17-2014, 12:26 PM
  #1326  
My Feedback: (2)
 
underdw's Avatar
 
Join Date: Nov 2004
Location: Arvada CO
Posts: 384
Received 5 Likes on 4 Posts
Default

The 2.5mm screws will drop down through the clearance holes shown in your picture. You will have to be sure that these holes are aligned with the counterbored holes in the bearing clamp underneath that. The screws will then thread on to the motor adapter that attaches in front of the motor mount plate. Again, make sure both sets of holes in the gearcase are aligned with the motor adapter holes as you push on the gearcase. Then add the 2.5mm screws and tighten them bit-by-bit, alternating each screw.

You are gonna love this drive!
Dan
Old 11-17-2014, 01:19 PM
  #1327  
 
Jason Arnold's Avatar
 
Join Date: Aug 2005
Location: Sydney, AUSTRALIA
Posts: 1,341
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by cartercg
Hi Jason,

Yip did look at the manual. The four holes are each about 4mm and way too big for the m2.5 bolts. Looking at the manual it appears that there should also be four smaller holes.

Cheers
Clint
Hi Clint,

You may have to rotate the rear bearing insert (for want of a better description) to line up the counter bored holes with the gearbox casing holes / motor manifold. The motor manifold obviously needs to be fitted to the motor first.

Cheers,
Jason.
Old 11-17-2014, 02:41 PM
  #1328  
 
Join Date: Jan 2009
Location: Johannesburg, SOUTH AFRICA
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the help, but I'm still battling. Could it be that the motor as supplied does not have the "bearing clamp" that is referred to? See pics of the motor with adapter, and the bottom of the gearbox casing. If I push the motor adapter into the bottom of the gearbox casing there is nothing between the motor adapter and gearbox casing that I can screw the m2.5 bolts through. If I look at the detailed cross section in the manual it appears that there should be some form of ring or clamp that would lock it in place. But I can't see anything in my motor. Is the "bearing clamp" missing. What does it look like. Could it have been accidentaly excluded when the drive was shipped? Is it a part that comes out of the bottom of the gearbox casing, or is it locked in place and not removeable?

Attached Thumbnails Click image for larger version

Name:	Bottom of gear case.jpg
Views:	659
Size:	103.1 KB
ID:	2048202   Click image for larger version

Name:	Motor with adapter.jpg
Views:	674
Size:	86.4 KB
ID:	2048203  
Old 11-17-2014, 02:46 PM
  #1329  
 
Jason Arnold's Avatar
 
Join Date: Aug 2005
Location: Sydney, AUSTRALIA
Posts: 1,341
Likes: 0
Received 0 Likes on 0 Posts
Default

Looks like you have a missing part to me... The manifold (bit screwed to motor) should insert neatly into an insert in the rear bearings which has four counter bored holes in it for the M2.5 screws.

Cheers,
Jason.
Attached Thumbnails Click image for larger version

Name:	Kh17788.jpg
Views:	673
Size:	60.2 KB
ID:	2048204   Click image for larger version

Name:	Qo38808.jpg
Views:	623
Size:	107.7 KB
ID:	2048205  

Last edited by Jason Arnold; 11-17-2014 at 02:54 PM.
Old 11-17-2014, 03:00 PM
  #1330  
 
Join Date: Jan 2009
Location: Johannesburg, SOUTH AFRICA
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks Jason, the part may well be missing, and I assume it is not something that easily comes out i.e. its not something that could have fallen out....it must have been missed in the assembly???? I'm sure Brenner will chime in when he reads the thread. I hope I am missing something basic, but fear that it is indeed a missing part. That would be a real pity as I want to fly it asap.
Old 11-17-2014, 03:09 PM
  #1331  
 
Join Date: Jan 2009
Location: Johannesburg, SOUTH AFRICA
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Yes, I definitely don't have that piece that attaches to the rear bearing and has the counter bored holes. Bummer.
Old 11-17-2014, 03:20 PM
  #1332  
 
Jason Arnold's Avatar
 
Join Date: Aug 2005
Location: Sydney, AUSTRALIA
Posts: 1,341
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi Clint,

I'm sure Brenner will fix you up with the missing bit. This is the part that's missing http://www.f3aunlimited.com/main-bearing-manifold

Cheers,
Jason.
Old 11-17-2014, 04:18 PM
  #1333  
My Feedback: (41)
 
Join Date: Jan 2002
Location: Algonquin Illinois IL
Posts: 2,347
Received 1 Like on 1 Post
Default

http://www.f3aunlimited.com/bjcinspire
The first production F3A Plane build for the CRP Unit. By BJ Craft.
Shipping to the customers next week. The planes are on a train to our location. So very soon.
We also stock every single part that Contra makes plus the motors from Neu that fit the Contra.
We have a very limited amount for sale. There is an optional easy to use mount to make installing it a breeze.
Thanks, Mike Mueller
Attached Thumbnails Click image for larger version

Name:	Inspire-1.jpg
Views:	722
Size:	195.6 KB
ID:	2048230   Click image for larger version

Name:	Inspire mount.jpg
Views:	637
Size:	186.4 KB
ID:	2048231   Click image for larger version

Name:	Inspire-2.jpg
Views:	774
Size:	189.4 KB
ID:	2048232   Click image for larger version

Name:	Inspire-5.jpg
Views:	790
Size:	191.3 KB
ID:	2048233  

Last edited by mups53; 11-18-2014 at 09:44 AM.
Old 11-17-2014, 05:50 PM
  #1334  
Thread Starter
 
Join Date: Jul 2007
Location: Bridgman, MI
Posts: 795
Received 11 Likes on 10 Posts
Default

Hey Carter,

It looks like Andy definitely screwed up. What's missing is the manifold that should be behind the bottom bearing.

I will ask Andy to express mail you a replacement gearcase with the correct part.

Please accept our apologies for this.

Brenner ...
Old 11-17-2014, 09:27 PM
  #1335  
 
Join Date: Jan 2009
Location: Johannesburg, SOUTH AFRICA
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks Brenner, got your email and I appreciate the quick help.

Regards
Clint
Old 11-18-2014, 11:37 AM
  #1336  
 
Join Date: Aug 2013
Posts: 38
Likes: 0
Received 0 Likes on 0 Posts
Default

There is a ring on the back side of gear case with 4 holes and 4 slots. You need to line up the 4 holes on that ring with 4 larger holes inside the gear case. Gary
Old 11-18-2014, 01:31 PM
  #1337  
My Feedback: (2)
 
underdw's Avatar
 
Join Date: Nov 2004
Location: Arvada CO
Posts: 384
Received 5 Likes on 4 Posts
Default

Mike,
Will that "optional" mount come with our planes, or is it purchased separately?
Really looking forward to an early Christmas!
Dan
Old 11-19-2014, 06:12 AM
  #1338  
 
Join Date: Aug 2013
Posts: 38
Likes: 0
Received 0 Likes on 0 Posts
Default

Brenner,
Did you have any input into the design of BJ Inspire contra design?
Old 11-21-2014, 12:09 PM
  #1339  
JAS
My Feedback: (2)
 
JAS's Avatar
 
Join Date: May 2002
Location: Around
Posts: 1,432
Likes: 0
Received 0 Likes on 0 Posts
Default

More importantly, how well does the mounting hardware in the Inspire photos work? Looks easier/lighter to work with. If it works well, can we purchase it separately?
Old 11-21-2014, 12:17 PM
  #1340  
 
Join Date: Jan 2004
Location: Galway, IRELAND
Posts: 237
Likes: 0
Received 0 Likes on 0 Posts
Default

It appears that the firewall / motor mount parts are separate to the kit. They can be bought from F3a unlimited or Bondaero.
The set up I use on my Nuance and Episode with the Hyde mount means I can take the whole drive chain out the front of the model( from the speed controller to the contra drive). That's what BJ has also designed. It looks like it will be lighter and much easier to install.
Old 11-21-2014, 04:51 PM
  #1341  
 
Join Date: Feb 2003
Location: Brisbane, AUSTRALIA
Posts: 493
Likes: 0
Received 1 Like on 1 Post
Default

I can highly recommend the Hyde mount for the Contra/ Neu combination. My setup sounds much smoother and quieter than other setups I have heard. I as well have setup my model so I can pull the motor/contra/mount through the front. Simply remove 3 screws and it's out. Servicing the drive is much easier if it's out of the model as well. It does isolate the gear mesh mechanical hum very well.

Last edited by PeterP; 11-21-2014 at 05:51 PM.
Old 11-22-2014, 09:56 PM
  #1342  
Member
 
Join Date: Aug 2013
Location: San Francisco
Posts: 49
Likes: 0
Received 0 Likes on 0 Posts
Default

I have the motor mount in the Inspire prototype I bought from BJ. The Neu motor went in easily from the rear and it is very quiet. I don't know if BJ will make it available separately.

Herb
Old 11-24-2014, 07:34 PM
  #1343  
 
DaveL322's Avatar
 
Join Date: Jul 2004
Location: Medford, NJ
Posts: 559
Likes: 0
Received 1 Like on 1 Post
Default

It has been awhile since I posted.....
Having flown the Contra for several years, my goal for 2014 was to improve the setup I found best for me (flown mostly in 2012/13 in a modified Bravo) -
Neu 1513/2Y F3A-1 (1300 KV)
9.89 gears
22x22F / 21.5x22R
Castle Creations Phoenix 80HV (ICE/Edge) with 30% brake
TP 5000 G8 Prolites
Throttle Tech

Basically, I wanted a setup that would "flatline" for an entire flight the power/speed the F3A-1 had at the beginning of a flight (without Throttle Tech being used). I wanted a setup I could fly in all conditions without changing props / gearing / etc. What I arrived at -
Neu 1512-2Y (1380 KV)
10.33 gears
22x22F / 21.5x22R
Castle Creations Phoenix 80HV Edge lite with 30% brake
TP 5000 G8 Prolites
Throttle Tech

In my 4,960 gram Contrast, this is a very potent setup and not something I would recommend for anyone not proficient with the throttle, but I think it is the type of setup needed to fly proper FAI sequences in windy conditions. It has a very broad speed range, and is “comfortable” flying fast or slow….acceleration and speed retention is very similar, consistent, and predictable whether flying slow at 150 meters, or going fast at 175 meters. Even with Throttle Tech onboard, full throttle is only used a couple seconds per flight in moderate conditions, and never in calm conditions. I limit the amount of full throttle in very windy conditions to places where I really need it – ie, climbing sections of integrated loop/roll maneuvers, and climbing sections of loops when going into the wind. A data log is attached to illustrate the amount of throttle being used. The log is of a P15 flown in a moderately heavy crosswind. The black line is the throttle stick output; the blue line is the throttle percent power output; and the green line is the current in amps. The tallest spikes at the beginning and end of the log are full throttle on 45 degree uplines. I’ve used as little as 2,500 mah for P15, but typically it is around 3300-3400 mah, and F15 is 3700-3800 mah.

The 1512 saves 30 grams, and runs about 10F hotter. The hottest temp I measured this summer on the 1512 was ~140F (well under limits), and that was after a big fast F15 sequence in the wind on a 95F day. Typical ESC temps are ~60F above ambient. I think the highest temp I’ve seen is 176F (well under limits). The higher KV allows the taller gear ratio (10.33) to be used and still leaves plenty of room to moderate the power at the beginning of the flight with Throttle Tech (I am using compensation factor of 19, nearly the stock setting). The 10.33 gear adds noticeably better downline braking compared to the 9.89 gear. A couple pics are attached to show some cooling details.

The "numbers", with Throttle Tech onboard, based on multiple data logs using an Eagletree Elogger, RPM data from Castle Edge logging, and a radar gun -
Full throttle 45 upline pre-sequence - 79 amps, 3,022 watts, 4157 RPM
Full throttle 45 upline post-sequence - 87 amps, 3,084 watts, 4177 RPM
Straight and level full throttle pass - 53 amps, 1,994 watts, 4350 RPM, 102.4 mph

Without Throttle Tech (65F ambient, essentially optimal temp if not using Throttle Tech) -
Full throttle 45 upline pre-sequence - 91 amps, 3,246 watts, 4205 RPM
Full throttle 45 upline post-sequence - 91 amps, 3,165 watts, 4065 RPM

Preflight static test at full throttle without Throttle Tech (65F ambient) is 99 amp, 3,528 watts, 4133 RPM. On a hot day, ~95F, the numbers jump even higher - ~110 amps and 4,000 watts.....just to give an idea how much power the unchecked setup has. And, for what its worth....my typical cruise speed on a horizontal line across the box is about 75 mph.

I've also run the 20.5x20.5F / 20.0x22.5R props, and they also perform very well. I find them to be a little faster in downlines and require a little more throttle management to maintain constant speed. They are very efficient in terms of performance offered for mah consumed, and they are very quiet. The "numbers", with Throttle Tech onboard, based on multiple data logs using an Eagletree Elogger, RPM data from Castle Edge logging, and a radar gun –
Full throttle 45 upline pre-sequence - 71 amps, 2,628 watts, 4205 RPM
Full throttle 45 upline post-sequence - 77 amps, 2,709 watts, 4221 RPM
Straight and level full throttle pass - 49 amps, 1,844 watts, 4388 RPM, 100.9 mph

Regards,



Attached Thumbnails Click image for larger version

Name:	101814 P15 Test Contrast 1512-2Y Contra 10.33 22x22F 21.5x22R 5000G8-51-49 EdgeLite80HV 4.19 med.jpg
Views:	179
Size:	163.8 KB
ID:	2049963   Click image for larger version

Name:	20141031_232642.jpg
Views:	199
Size:	2.10 MB
ID:	2049964   Click image for larger version

Name:	DSC00703.JPG
Views:	223
Size:	167.7 KB
ID:	2049965   Click image for larger version

Name:	DSC00704.JPG
Views:	196
Size:	233.3 KB
ID:	2049966   Click image for larger version

Name:	DSC00705.JPG
Views:	201
Size:	144.7 KB
ID:	2049967   Click image for larger version

Name:	DSC00721.JPG
Views:	318
Size:	186.5 KB
ID:	2049968   Click image for larger version

Name:	DSC00728.JPG
Views:	200
Size:	133.9 KB
ID:	2049969  
Old 11-25-2014, 06:23 AM
  #1344  
My Feedback: (2)
 
underdw's Avatar
 
Join Date: Nov 2004
Location: Arvada CO
Posts: 384
Received 5 Likes on 4 Posts
Default

Thanks for the detailed info Dave!
Couple of questions:
1) Does the throttle tech save you energy (mah) during a flight? Are you sold on it, and if so, why?
2) Have any Contra flyers have trouble with the sound check at Nats?
3) What model of Neu do we get when we order from F3AUnlimited? (didn't know there were different flavors)

Thanks, Dan
Old 11-25-2014, 07:07 AM
  #1345  
 
DaveL322's Avatar
 
Join Date: Jul 2004
Location: Medford, NJ
Posts: 559
Likes: 0
Received 1 Like on 1 Post
Default

Hi Dan,
1. I use throttle as needed based on my perception of the airplane speed; not the attitude of the plane. Ie, I don't go to full throttle in every climb simply because the airplane is in a climb. So for me, where the time and pace of my flights is similar with and without TT, I have seen TT save as much as 20% mah for other pilots.
2. No noise issues I know of at sound check. My plane checked 91-92 db.
3. Lots of different sizes and kv Neu motors. Mike at F3A-U will be stocking the 1512/2Y "contra" version.

Regards,
Dave
Old 11-25-2014, 04:13 PM
  #1346  
OhD
 
Join Date: Oct 2002
Location: west hills, CA
Posts: 1,160
Received 8 Likes on 5 Posts
Default

Thanks Dave. Great work and great data. Your setup definitely has power to spare as far as P-15 goes. You are using a very small part of the throttle range but you seem to hit the same spot (on the power up end) very consistently. I'm impressed you don't exceed the maximum power needed at any time. I'm not sure how many pilots are capable of doing that. I've been flying P-15 only, and set my system up so full throttle stick is the maximum power I need so I don't have to worry about overpowering it. Makes it a lot easier and I find myself using less peak current and less capacity. I believe the batteries will love this and last a lot longer.

It may not be clear to everyone that what you have is a "Top Fuel" power plant that is pushing the limits of the hardware specs and most people don't need it and maybe can't manage it and as a result could damage the equipment. Anyway, it is good to know the power is there if and when someone needs it. Keep up the good work.

Jim O
Old 11-25-2014, 04:40 PM
  #1347  
 
DaveL322's Avatar
 
Join Date: Jul 2004
Location: Medford, NJ
Posts: 559
Likes: 0
Received 1 Like on 1 Post
Default

Jim,

Thanks! Re-reading my post, I agree with you that I should have stressed a bit more that my setup is very capable of abusing the lipos if not used judiciously. A couple relatively simple adjustments to make the setup less "topfuel" would be -
1. Increase the compensation factor on Throttle Tech from 19 (20 is stock) to about 25.
2. Changing to the 22x20F / 21.5x20R.

Either change should drop peak current by about 10%, and the performance offered will still be very strong. I've been a big advocate of the Neu motors for many years now. Single prop or contra, they have a ton of torque and a very flat torque curve, and I think my setups show that they are very efficient over a wide range. Those characteristics, for me, make for a "friendly" setup that is easy to modulate consistently in the mid stick range.

Regards,
Old 11-28-2014, 10:18 AM
  #1348  
 
Join Date: Jan 2009
Location: Johannesburg, SOUTH AFRICA
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Very interesting Dave, I should have my contra drive Peridot flying within the next few days and it will be interesting to see what the speed is like. Your setup is very interesting and appears to be a good reference for a high power and speed combination. I expect I'll end up trying the 22/22 rear and 22/20 front prop combination. The number of combinations of motor kV, gear ratio and props certainly adds to the options. What has previously struck me watching the contra drives fly is that they are great in calm conditions, but lack speed and penetration in the wind. That was certainly my impression watching some of the contra setups in the stiff winds at the world champs in South Africa. But I expect that the lack of speed in the wind is really a setup issue, and that one either needs to be prepared to have to swop props out for high wind, or run an aggressive setup and carefully manage the throttle, as you are doing. Very insightful feedback. Thank you.

regards
Clint
Old 11-28-2014, 11:54 AM
  #1349  
Thread Starter
 
Join Date: Jul 2007
Location: Bridgman, MI
Posts: 795
Received 11 Likes on 10 Posts
Default

Hey Clint,

I had the pleasure of judging Dave in the 2011 USA Nats f3a final. Dave was crowned USA National champion that year, and it was well a well deserved win. Dave's setup was spot-on, and this could be very easily seen when judging him back to back against many of the nation's best pilots. (Dave was pretty good too..)

The conditions were quite windy, but what Dave's plane had was "speed range". He was able to continuously adjust his roll rate and his speed relative to ground to make the wind virtually disappear, whereas other pilots noticeably struggled. This was particularly noticeable on maneuvers like the rolling circle, where most pilots were being blown over the place.

So, I think that the take away here is that Dave's setup is definitely a "hot setup", but more to the point, I think it's also a very personalized setup as well, and based on my personal experience with Contra setups, I'm guessing that it was also very personalized with respect to the Bravo that Dave was flying too.

It is definitely true that Contra Drives work well in Calm conditions, but it also true that a Contra setup can be made to fly fast as well. However, a lot of this is influenced by the design of the plane. Contra Drives seem to work better with planes that have low drag, and are capable of flying fast, because the Drive can then pull a plane like this through the air fast in the most efficient way without having to burn a lot of mahs pushing air out of the way.

Then when the plane has to slow down, the Contra Drive can provide all of the drag that's needed to make the plane fly slow. In this way, you get the best of both worlds.

Brenner ...
Old 11-30-2014, 10:42 AM
  #1350  
 
Join Date: Jan 2009
Location: Johannesburg, SOUTH AFRICA
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks Brenner and Andy for shipping the replacement gear case with the missing part now included. I got to fly the contra drive today in my OXAI Peridot, which I have had over 1100 flights on with a Pletti Advance. Being so familiar with the plane I could immediately tell the difference of the contra drive setup. My setup is a Neu F3A motor with a 10.33 gear set turning 22/20 rear and 22/18 front props.

The contra is a big change. Throttle feel is very different, and on my first flight one of the uninformed observers remarked on how constant the speed was. The breaking is very significant, and I ended up having to reduce my end break on the spin99 to only 24%. I previously had a tiny bit of low throttle to aileron mix to prevent a slight roll on the downline with the break activated. That mix was removed and down lines are plumb straight with no roll. Rudder is more sensitive, as is elevator, both as expected to be.

I still have a fair amount of setup to do, as the contra significantly changes the base setup, but the benefits are very apparent. Stall turns are a prop hanging piece of cake. Rolls are very axial, and up lines and rolls on up lines are very true and far less speed dependent to hold heading.

The Peridot has never really liked to fly slow, but it's speed envelope with the contra is significantly wider. It is now able to fly slower while retaining control. Downwind rolls can be done with lower airspeed. Even at fairly low throttle settings there is sufficent flow over the tail to keep rolls axial and give good control.

I kept the same throttle end points as I had on the Pletti, and initially I found it was flying very slowely, with little acceleration and speed. I later realized I was not getting fill power, and after increasing the end point it then felt much better. I think this setup will be great for calm and moderate conditions. I expect I will need to consider a different prop combo for high wind, and am thinking of trying a 22/22 rear and 22/20 front, or just swopping the front to a 22/20 so that front and rear are both 22/20.

The Peridot was previously very stable in yaw, which is a characteristic that I really like. With the contra there was a slight reduction in yaw stability, but I don't think it is a problem. I need to fly her a bit more and in different conditions to get a feel if I need to consider some add-ons. I don't think she will need any.

I'm impressed with the drive including the Neu motor, which is clearly very powerful. The Neu motor was temped at 49 deg C on landing, with around a 25deg ambient, which is great. No cooling issues with this setup.

I need to get some more flights in, and will then revert back with further impressions. Thus far I am impressed.

Regards
Clint

Thread Tools
Search this Thread

Contact Us - Manage Preferences Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.