sjhanc

My Feedback: (3)

I posted an answer above about your question about the Varioprop nut. You need to order the prop-spinner adapter nut when you order the prop. Giving the hobby dealer the motor-spinner information will get the correct parts for you. There is a 10-12mm shaft sleeve and a 10x1.25mm nut and washer available. The nut is tapped 4mm for a spinner bolt. You will have to get the 4mm bolt in the correct length from local supply or the spinner manufacturer.

sjhanc

My Feedback: (3)

If you buy a 6 pack of 4000mah 30c 4cell lipos and wire them 12s2p that would give you 8000mah and a cool running flight pack. If you get a cell go bad replacing 4 cell lipos is easier and cheaper than 6 cell packs. I have found it to be difficult to get replacement 6 cell packs identical to the ones I already have because they seem to discontinue them when they sell out the current stock. The newer packs offered are different from the older packs, so if you don't buy spares that whole pack is out of business when 1 cell puffs or fails. This has happened several times to me over the years. I have a collection of 2 meter to 3.1 meter sailplanes with geared Hacker motors so my large battery pack experience goes back to the days of 24-30 cell Ni-cad packs. There is a much greater demand for the popular 4 cell lipos so warehouse stocks of them are around for a longer time. When lipos first became available I bought single or 2 cell batches and built and wired them myself. When balance chargers came out I bought the balance plugs with wires and did that too. The retailers wanted to make more money so stopped selling single lipo cells. So now it is possible to buy packs that have dead cells built in. I always charged single cells and tested them for capacity and nominal voltage, matched cell packs last much longer. The more expensive battery brands do this matching for you so are less likely to ship you a bad pack.

mark IX

My Feedback: (9)

SJ, have you noticed this ringing noise issue with the R50 motor, or just with the R65? I was watching a number of videos with the R65, R50, and the P360 and the R65 seemed the noisiest. The P360 was noticeably quieter.

Mark

sjhanc

My Feedback: (3)

mark lX,
I had the noise problem with both motors. The fix I tried on the R 50 seems to have worked permanently as there have been no further problems with it. The R 65 however, maybe because it has a longer rotor continues to ring although at a reduced level. I am going to disassemble it one more time and try again-if not successful I will get a P 360. No sense beating your head with the same hammer if another will do a better job. I plan to use the P 360 on the H 9 Mustang anyway so the current plane will be a good mule to test it on.

sjhanc

My Feedback: (3)

I got around to disassembling the R 65 motor after taking a week off and was disappointed to find cracking epoxy around the magnets. This is certainly a result of the ongoing vibration/noise issue I have had with this motor. As I can't ignore the possible imminent failure I am retiring it. I won't risk the airframe and other gear in it by pushing it further. I was planning to buy the Eflite P 360 for use on the front of the H9 60cc Mustang so I will try it out on the TF Mustang to work out the 4 blade installation. The R 65 is a powerful motor, it just needs better quality construction and an additional bearing to be competitive with other available brushless motors.

sjhanc

My Feedback: (3)

One good result I can report is on the ROBART electric retracts. After an initial glitch caused by a linkage barrel stripping itself at 1 1/2 cycles and repairing it by making this part myself I have had dependable operation ever since. I wish ROBART could find a way to speed up the retracts' up and down speed as from my experience flying in the full scale Mustang the retract speed of the RC gear is at least twice as slow as the full scale gear. (10 seconds each way). I stop-watched the gear up speed of a Full scale P 51 C from the moment I could see the left gear begin to move until both gear were in the wing at 3-4 seconds not counting the inner gear doors. It is possible that improvement made to the real plane's hydraulics make them faster than P 51 aircraft flown during WWll but I have never heard of this myself. I use a 2000mah 5 cell NIMH receiver pack to power my gear. I experimented with higher voltage but the speed difference was about .3-.5 seconds faster.

mark IX

My Feedback: (9)

Steve, could you post some pics of the cracked epoxy. I wonder if heat is also contributing to this issue.

Thanx, Mark

Mpizpilot

My Feedback: (45)

I finally got to see mine in the sun after a long long winter hiding in the basement. Can't wait to fly it. Hopefully this Sunday.

sjhanc

My Feedback: (3)

Here is what it looks like now. Last week I meticulously cleaned the rotor, You can see bits of grey (magnet pieces) and amber (epoxy) throughout.
In the center picture the magnet in the center is the thick magnet that I ground down last year. The inside of the rotor has magnetic debris all over. All of the magnets show some degree of contact with the stator. The green epoxy is placed there by the man. for balance. The amber epoxy is lifting where it is thin around the magnets. There is a large piece of magnet bridging 2 magnets in the left picture. A large piece of amber epoxy has flaked off of the close end of the center magnet in the left picture and is just opposite the grey piece on the edge of the magnet. I have checked temperatures repeatedly with a wifi gauge attached to the rear aluminum frame in flight and it never reads higher than 135f even after doing 165amp maneuvers. If it was overheating in flight it would be too hot to touch for 8-10 minutes after a flight-IR temperature readings on the ground after a flight give readings less than 130f any where on the motor.
ESC temps are typically below 120f for a flight.
After assembly with a new motor shaft and bearings and proper end play set (.002 inch axial) I run the motor at low speed and determine the smoothest position for the rotor on the shaft (2 locations). I then set the smoothest position (360 degrees) for the prop driver. I set index marks for each part as it is installed. I don't accept any vibration at all. then I add the spinner back-plate, index it, and add a stub balanced prop hub and prop nut. If there is any vibration felt at any point I backup and get it right. The difference between very light vibration at full throttle (no blades) and perfectly smooth is 200-300rpms. In other words-if I can feel any vibration at all in the nose of the plane it runs at 6900-7000rpms. With no vibration it turns 7200rpms. This is with the large spinner installed but no blades. Loaded with various props it runs between 5500- 6200rpms depending on the prop installed.
The noise-vibration occurs at 1/4-1/3 throttle just as the tail comes up, this tells me that inertia acting on the rotor and prop-spinner assembly (gyroscopic precession) during the pitch change is bending the rotor enough to touch the stator briefly. There is usually no noise during the flight and the throttle is at 45% for flapped landings. When the motor was new it complained loudly at all times when ever throttle went through 1/4-1/3. The bearings only lasted 6 flights.
I have extensive training and experience in both full scale aircraft and helicopters in locating and solving the shakes and later working on cars and trucks. When I found a problem then we would just change the part or assembly. I should have returned this motor in the beginning and be done with it. Saving a few dollars trying to save a suspect motor is a waste of time, but I gave it a try anyway.

mark IX

My Feedback: (9)

Steve, looks like you've done a thorough job of investigation here. I am wondering if the 4 blade props contributed to these issues you are seeing with the R65. Did this noise or magnet contact appear when you were using the 2 blade props? The R65 maybe powerful, but it looks like the P factor of these larger props is causing a cocking action, which in turn causes the magnets to contact the stator, resulting in the ringing noise. That is puting an unacceptable side load on the bearings, hence their short life.

My second choice for a motor was going to be the Turnigy CA80-80 from HK. I'm not sure of the bearing config of that motor, which I am now going to take a closer look at. There is someone in Norway who is using this motor on the same Spitfire that I have . May be worth contacting him to see if he has experience with this type of issue, or at least he can verify how many brgs and their location in the motor. If it is constructed like the P360 ( screws located at the far end of the rotating bell hsg as shown in the P360 pics) than perhaps that motor will have the center brg needed for the durability that is required for these larger props.

Also, there is someone on RCG who is using a Turnigy Rotomax 50cc motor in his H9 Spitfire, (81" ws, 22 lbs) turning a 20x10x4 Biela prop. He goes by the name of Tagesol. Looking at the pics of this motor, it has screws at the far of the bell as well. He is operating it on 12s 500mah batt, and a Castle 120HV.

Thanx, Mark

sjhanc

My Feedback: (3)

I have had this noise/vibration issue with this motor from the very first flight. The size of the prop does not seem to be a factor. I tried smaller 20-12 and 22-10-12-14 inch props but usable thrust was anemic at best. It works best with 24 to 26 inch 2 blades and 14-15 inch pitch. The 4 blade Varioprop loads it about the same as a 22 in 2 blade but increasing pitch restores speed and climb. The Zinger 4 blade is a definite over load with the thick blades.
I believe that other manufacturers discovered this problem early in the development process and fixed it with the concentric bearing. I have read older posts by others using this motor having a similar problem but they were always advised to change the ESC programming.
I frequently see this motor for sale as used-like new but no mention of any issues. It makes me wonder. I have noticed a trend with a few manufacturers toward a very large diameter rotor but with short rotor length. Hacker is an example with their 3D motors. The R 65 has a shaft diameter of 10mm while some others go with 12mm. The thicker shaft would go a long way to stiffen the motor shaft.
The R 50 motor had the noise when new but after I modified it no more problem. It was however, over loaded by the 22.6 inch 4 blades. I had planned to buy the 19.9 inch blade set to try with the R 50 motor, I will go ahead with that.
I started flying with my first TF D model using a Fox 2.4 ci gas motor and 20-10 and 20-12 APC props. That plane reached the highest top speed I have yet recorded at 122mph out of a dive but broke in half because of a structural design flaw. This problem is easily fixed if you care to. TF has known of the flaws their plane has since the very beginning yet has only corrected the wing joiner, ignoring the others. I think they believe that few pilots will achieve long life with this plane so why fix it.
I for one will be moving on to other brands. I normally get 250 to 300 flights with my P 51 models and a few of the planes (2) went down with other causes (battery disconnect, servo failure, and a repairable dead stick on TO). The structural failures were a broken wing, and a broken fuse. TF fixed the wing joiner problem and I modify the fuse for greater strength at the bulkhead locations. You know about the landing gear problems.
The bearings used in the R 65-R 50 motors are the same as those used in the automotive industry for decades in alternators. Alternators have a rotor much larger and heavier than the Rimfire motor does and have a belt side load. They can go 100,000 miles or more and the pulley ratios are set to run the alternators at 1 1/2 times crank speed. They seldom have vibration issues so I think the Rimfire vibration problem is the primary cause of bearing failure, a secondary problem being propeller forward thrust (these are not dedicated thrust bearings) and finally gyroscopic precession. In my military service on full scale helicopters, there were a number of thrust bearing sets used in rotors, transmissions, and turbine engines that all required special inspection procedures for orientation marks and wear. These bearing sets came out of the box with serial numbers and installation marks and could not be mixed with other bearing sets.
When I fly P 51 aircraft I always use smooth maneuver techniques that minimize stress on the motor and airframe. The only rapid pitch change is during the TO when the tail lifts and that is when the noise is obvious.

Growler84

My Feedback: (8)

Interesting data in these recent posts. I say that because I too have a R65 and its been powering my AeroWorks Mustang for almost 3 years now. This setup was my first foray into electric 50cc-sized Warbirds. Keeping in mind that I knew very little (and still do in many ways), I tried to go the 4-blade route and ended up frying my first R65 with a Biela 23-14 4-blade. It would turn it on 10s but yielded no performance. When I tried 11s there was much better thrust but 30 seconds into it the burning smell happened and that was the end of that motor. Tower was awesome and sent me a new R65 and I ended up settling on a Zoar 2-blade 22 X14, usually running on 11s, sometimes 12s. The performance is very good, in fact its better with fresh batteries than the plane was with the DA-50 in it previously. I do 7 minute flights on 5000 mAH packs. YES, mine screeches on rapid throttle up as well. I just wrote it off to timing issue and pressed on...for almost 3 years now. So based on your superior experience and data, I probably should swap that motor out. So on that subject:

I use a Turnigy Rotomax 50 in my BH Westland Wyvern. Same Zoar 22 X 14 2-blade, 11s or 12s, Castle 120 ESC and 5000 packs. I've run this setup for a year now and must report the Turnigy motor is significantly more powerful than the R65 on the same cell count. Of course it burns a bit more battery so I fly this package 6 minutes. It is smooth and does not screech when your throttle up. I bought that motor knowing there is no customer support, but in this case I lucked out because it is a good one. Considerably cheaper too at $180 when I bought it.

Final note, either the Mustang or the Wyvern are flown every weekend because we can only fly electric at my field on Sundays.


You guys are way ahead of me in the knowledge department, I just thought I'd lend my meager data to the discussion.

sjhanc

My Feedback: (3)

I have no complaints about the R 65 power, in fact I was very surprised that it delivered the high levels I actually got out of it. Other than the noise it makes at 1/3 throttle it is quiet and very powerful. My issue is in being unable to solve a reliability defect that has now reached the point that I can't risk a valuable airframe. The cost of this motor is small compared to the whole airframe package. I am at the point of moving on to another motor and I am looking at the more expensive alternatives and now that I am aware of the various brands and their methods of design and construction I want to make the best choice. I looked closely at the Biela prop you tried and bought the Varioprop.
Now I have a lot of data on flying with 4 blade props I am moving up to a larger airframe that can carry more battery capacity for duration. Now I know how to do that too. I watch a lot of pilots whose ambition seems to be to show off what THEY can do with the plane they are flying. My goal has always been to fly a plane that a lot of people like for various reasons and fly the plane in a manner that shows off what the PLANE can do. When I flew 3d planes nobody paid any attention to them and I realized that if I practiced all day every day I would never improve my flying skills to enough to satisfy me. I looked around and saw that warbirds attracted a lot of spectator interest, and I had flown smaller versions of several warbirds. I admit that nothing flies as well as a Spit or Zero and the P 47 is the easiest to TO and land. I was interested in Corsairs but knew I would have a lot of bad landings so chose the P 51 as a good compromise. Wrecking one did not discourage my enthusiasm so now I own 3 and am buying another.

Oh, yes I tried several Xoar props on my R 65 from 22-14 up, E but the best performance was had with Xoar 24-14E, 26-14E and an APC 26-15E prop, the last giving an excellent vertical rate of climb, better than the rest. I tried props for gas engines also but none worked better than the electric props. One of the club experts informed me that real Mustangs never climbed vertically, I didn't tell him I had seen a real Mustang go straight up at an airshow for 4-5 thousand feet, I was impressed by that, until I saw it in person I would not have believed it either. I stopped the vertical climbs with my own plane because it just uses too much battery capacity. I have never operated my plane on less than 12s packs but have moved to 12s 2p packs because it is easier on the cells.
I am going to put together a video of the all the close passes using the 4 blade Varioprop. I think I can get a 3 minute video out of the footage I already have.

mark IX

My Feedback: (9)

Thanx for the info Greg. Have you tried any 4 blade props with the TR50 (Turnigy Rotomax 50)? These large 4 blades seem to be giving these motors a run for their money. That is our goal, to find a reliable motor /prop combo that will supply the power for an acceptable flight envelope. From what I've learned about the TR motors, it looks like the TR50 and the Turnigy CA80-80-10 motors have a concentric rear bearing at the rear of the rotating bell housing. This is the weak link in the R65 design since it lacks this concentric bearing config. creating a cantilevered bell housing that is unsupported at the rear of the housing. Below is the description on the CA80-80-10 from the HK website:


Turnigy CA80-80 Brushless Outrunner (50~80cc Eq)
"Designed as a 50 to 80cc gas engine replacement, this motor is a direct bolt in for 17~30lb Sport, Scale and 3D planes .
A perfect size motor for 3D flight up to 20lbs.
The motor is very well built with strong mounts, end bell and a concentric double bearings at the rear to support large propellers and rotating can, especially during hard 3D flight".

I believe your TR50 is built the same way. Take a look at the back of the rotating bell housing and you should see screws around its diameter, that fasten the bell to a rotating member that is attached to the motor shaft thru a bearing. Post some pics if you want.

Thanx, Mark

Growler84

My Feedback: (8)

Thanks Mark, now I understand the bearing subject as it relates to the Rimfire motors verses the Turnigy motors. This is good data because my next electric will be a Don Smith P-61 (100") and I was agonizing a bit over Rimfires or Turnigys for motors. No I have not tried any 4-blade setups on the Rotomax 50. I run gas Zoar 22 X 14s because the Rotomax uses a DA, DLE 4-bolt pattern prop hub.

I will pay attention because I sure would like to fly my Mustang with a 4-blade even if I do give up some performance. The P-61 definitely needs 4-blades!

mark IX

My Feedback: (9)

Have you looked at the back end of the rotating housing to see if it is supported by a bearing? The problem I have with Turnigy motors is I don't have any experience with them and spare parts. At least with the Rimfire motors you can get replacement bearings and shafts if required, here in the states.

Mark

Growler84

My Feedback: (8)

No I have not, I just know from 1 year of experience that it does not screech during acceleration. I agree on your second point, like I said a couple of posts ago, I acknowledge and accept that there is ZERO customer support from Turnigy/Hobby King so for me their products are throw-away items when they fail. To date the Rotomax 50 has not failed. I need to mention my friend Mike has a Rotomax 50 in his Aeroworks Mustang and its been going strong for over 2 years. So there is some data to support the notion that they work.

sjhanc

My Feedback: (3)

Growler84,
Your early experience with the R 65 and overheating and burnup suggests poor airflow around the motor. My first day flying my new R 65 heated to around 200f during a 3 minute test flight. This is close to hot enough to cause damage. I flew 1 more short flight, got temp readings on the motor both in flight and using an IR temp meter and again got high temps. Castle data from the ESC showed 165F with it too, mostly at the moment I throttled back- It would zoom up from 135f to 165f for a few seconds.
When I got it home a lot of thinking gave me the idea to try ducting air from the scale carb intake air scoop up to the top rear of the motor where temps got the highest. This dropped motor temps to 160f and by moving the ESC to in front of the firewall and under an air-ply baffle the ESC temps dropped a little. I ran it this way for around 30 flights while I tested prop sizes. Since internal airflow in the R 65 is in at the back and forward to the spinner back-plate I got the idea to increase the spinner back-plate to engine cowling clearance from tight to 1/4 inch. This dropped the motor temps. down to 134f peak and the ESC recorded max temps from 110f to 120f.
The air duct I use is corrugated auto-motive heat riser duct available from auto parts stores. It is cheap, available in various sizes and is easily bent and shaped to fit. I use my fingers and a 3/4 inch wood dowel to shape the front to fit the scale intake.
You have limited motor temps by using 10-11s packs but you are giving up about 4 hp and a lot of rpm.
I tested my setup with every prop size and brand and found that the R 65 works best with large, high pitch props. The best performance was had with XOAR 24-14E, 26-14E, And an APC 26-25E prop. The APC was the cheapest and the best performing. I tried all sizes of wood props and a couple of carbon fiber props I have on hand but they all had high current draw and less performance.
I have posted pictures of the duct setup both in this thread and on my RCU page if you are interested.
Update- 5/24/15 Since I have switched back to the R 50 motor and Graupner 22-12 prop I have about 20 flights using 12s 2p (24 cell motor packs). I haven't yet extended my flight timer past 5 minutes but have had several flights where I was forced to go around more than once for landings. A couple of these flights lasted 7.5-8 minutes for a safe landing to be executed but never used more than 5000mah out of a 6600mah 24 cell pack. These 24 cell packs seem to be not as strained as the older 12s 5300mah packs were and never even get warm. I can put them on charge immediately as compared to the older 12s packs which had to cool for at least an hour before recharging. And with less capacity actually used the 24 cell packs take less time to top off- One of my older chargers sometimes refuses to charge them as the discharged cells are reading 3.7 volts which it determines is fully charged.

mark IX

My Feedback: (9)

Here are some pics showing the construction of what I believe is the Turnigy CA80-80-10 motor I found on a website used for scooters and Karts. Unfortunately the site is written in German so I can't read it.
Note the concentric bearing set up at the rear of the housing. The 1st pic shows the concentric bearing with the motor mount removed. The last 2 pics are of the front of the motor showing the rotor bearing and the front brg in the bell housing.
.



Also of note is that if this motor is used with the belt drives needs to power thses Karts and scooters, this says the the bearings are capable of with standing a fairly high side load.

BTW GROWLER84 how did you mount your prop and spinner the the Turnigy motor? Is the bolt pattern similar to say a DLE55?

Mark

Growler84

My Feedback: (8)

Mark,
Yes the bolt pattern is the 4-bolt setup found on DA/DLE with the same 10mm shaft size and the shaft is tapped for spinner usage.

Growler84

My Feedback: (8)

sjhanc,
All valid points concerning the cooling and your findings. My ESC is on the bottom of the engine box right in the carb intake airflow. My spinner has holes in the back plate and since I scrapped the 4-blade idea I have two extra prop openings on the spinner. I also use louvers to exhaust the hot air (in all my models) with great success. I've been flying this model consistently for almost 3 years now including during the Vegas Summer months where the temperature averages 105 deg F. You are correct however, I've wrestled the beast to a standstill and fielded a very reliable and for me, powerful 2-blade compromise. I have too many other projects to jack with a well-functioning setup however, I am paying attention and will definitely go 4-blade on my upcoming P-61. Many thanks for the info.

sjhanc

My Feedback: (3)

Growler84,
There is 1 important fact that you may have overlooked, the air flow through the motor itself is from back of the motor to the front and out the motors spinning front case where it hits the spinner back-plate. from here it has to turn 180 degrees and flow back along the rotor transferring heat into the rotor and then pass by the rear intake opening where it is sucked back into the case-and now heated by its first pass it flows back to the front again getting even hotter. This is why there is a constant heating effect to the motor over its operation and high temperatures occur near the end of a flight. The openings in the spinner are effectively canceled by the high energy flow through the motor, providing no cooling effect. The duct I use in my setup provides a constant supply of cool air at the cooling intake slots in the motors rear case. It is sucked in and maintains an even temperature in the winding. You can verify this air flow by running the motor without a prop or spinner on it and feeling the air coming out of the front. It is a pretty good flow.
Unfortunately the P 51 engine cowl is not designed to encourage air flow around the motor in a manner that insures cooling. You can create good air flow by supplying cool air where the motors stationary rear intake slots are located, It sucks it in and forcibly expels it out the front. The air duct alone lowers my operating temps to a steady 165f. Some time later while doing balance checks with the spinner back-plate installed but no prop or cone I noticed pressurized air leaking out of the air gap between the cowl and the back-plate even though this gap was only .030 inch. Thinking that this could possibly be used for cooling I shimmed the motor forward on its mounts to increase the gap to 1/4 inch. This worked better than I expected lowering the motor temp to a constant 135 degees f no matter how heavy the prop load was. It is possible that the larger gap alone could effectively cool the motor. This gap is in a low pressure location because the spinning propeller air flow is naturally outward due to centrifugal force. You can see this in action by observing the vapor trails around the nose of propeller driven carrier planes during high humidity deck operations. The vapor moves away from the nose and then comes back to the fuse further back near the wing roots. In this picture I took while in the process of moving the ESC up front to mount under the air duct, I also cut a slanted ramp in the bottom of the firewall-it is about 1 1/4 inch deep and tapers to meet the belly sheeting at the first former. The air duct is glued to 2 balsa block at the rear. I pinched the front of the duct down to the general shape of the scale carb intake in the cowl, later I closed it even more to allow some air to flow around it for ESC cooling.
This setup allows this motor to operate at high power levels constantly with no overheating. As you know the TopFlite P 51 always needs at least 60-70 amps even to fly at low speeds and when the gear and flaps come down amp draw goes up to 90-110 amps for landing. This is a result of its wing air foil not being efficient at low speeds. I am not familiar with the Aeroworks P 51 airfoil-I hope it is better. I know the Hanger Nine P 51 has an excellent air foil, it can actually glide in at idle for landings.

Growler84

My Feedback: (8)

Wow, you are seeing a lot more amps on average than I do. My Castle download says my max amp draw is in the low 80s, my flight average is below 30 amps. Again, this is 11s but I think we are seeing why I do not have a cooling problem. I fly very scale and use the power judiciously. In fact, go here and take a GoPro ride in my Mustang, pay attention to what the throttle is doing:

https://www.youtube.com/watch?v=UTbCNc7NuoE Make sure you unmute the sound at the bottom of the screen on the left.

https://www.youtube.com/watch?v=UTbCNc7NuoE

sjhanc

My Feedback: (3)

Your link didn't install.

Growler84

My Feedback: (8)

That's weird, I'm looking right at it on my computer but tried it on another and indeed its not there. I dropped the link in separate, lets see if that works.