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MrDGH111

Boomerang motors keep blowing !!!

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15 hours ago, Wooders28 said:

Fully ballracing, gearbox and axles, i consider a must on all my cars (although ive not checked the bullhead yet! ūü§Ē), as it increases battery life, aswell as speed, and reduces the chance of motor damage etc.

Ok, looks like ive gotta give this a go, thanks for your help

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On 13/03/2018 at 4:43 PM, Backlash said:

I just checked the Boomerang manual, and it appears that the Boomerang has plastic or metal bushings on all of its rotating parts like axles and gears.. These bushings can create a lot of resistance in the drive train, and can put more load on the motor which could be part of the reason why the motor is over heating..

As said previously, 30 year old grease can dry up and also put excessive loads on the motor as well..

Bearings are cheap to buy now, and you could probably ball race the whole car for not much more than the cost of a new motor.. It would only take 10-15 minutes to replace the bushings in the wheel axles with bearings, but to do the gearboxes, you will basically have to disassemble the whole car.. If you are going to have the gearboxes apart, then you may as well clean the old grease from the gears and re-grease them at the same time..  

Did you build the car originally??  I'm getting the feeling that you are a little reluctant to disassemble the car and do the maintenance that the members have suggested like cleaning and re-greasing the gearboxes, and fitting ball races... If you are able to do this work yourself, take it as an opportunity to do the rebuild with your son, and show him how the car works..

If you don't have a manual, you can find one on the main site here ..  https://www.tamiyaclub.com/manuals.asp?cm=369

Also, running the car on grass (or sand) can cause excessive load on the motor.. A large concrete or asphalt area like a netball court, or unused carpark would be better area to run the car.. Likewise, a hard packed dirt area like a BMX track, or bush land would also be suitable..

Ball bearings and re-grease looks like the way forward (and another new motor...Silver can again i guess ?)

Yes i did build the car originally, good idea to include my son with this re-build.

Thanks for the manual link, itll be very helpful.

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On 12/03/2018 at 1:10 AM, WillyChang said:

Also depends where you're running... if it's a small area (like smaller than half a tennis court) AND you're running the LARGEST possible pinion gear (="highest" gearing) then you'll be forever accelerating & yeah it's not hard to cook even a silvercan.

Use lower gear (smaller pinion) for tight areas, largest (think its 17?) for wide area speed runs. 

Lower gear = more torque, car might feel less sluggish on pickup too.

Interesting info. thanks

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On 12/03/2018 at 10:02 AM, MadInventor said:

I recently had to do some maintenance on my re-release hotshot which is only 10 years old, and the grease has gone 'sticky' in that already. As other suggest, strip and degrease, then re-grease, re-bearing, and re-assemble. Also another quick check you can make is to take off the wheels and triangular drive hubs and make sure there is no grass or other obstruction wound round the axles. Running on grass will also heat up a motor a lot faster than running on a hard surface such tarmac or hard dirt.

 

Yes does last a little longer on tarmac, just not as much fun though, but neither is fitting a new motor every 2 hours so i guess i have to change my ways.

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On 12/03/2018 at 12:57 AM, Jonathon Gillham said:

I run my bashers for around 30minutes a time with TBLE-02S and silvercan or torque tuned and haven't had any problems.  These are generally TT02B and Monster Beetle, but I have run my rere Boomerang for that long and a Novafox as well.

These are new though, well less than 18months old and have bearings and a bit of maintenance.

Im learning quite a lot here, i was hoping for an hours worth of non stop fun, i bought 2 batteries [4400mAh], so i could switch batteries when the first went flat, its looking like im gonna have to get used to the idea of a maximum of 30mins. Is there no way of achieving 1hour ? no way of improving the cooling of the motor whilst its been used ? 

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Sure drop in a 45-60T crawler motor ;)

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4 hours ago, MrDGH111 said:

Im learning quite a lot here, i was hoping for an hours worth of non stop fun, i bought 2 batteries [4400mAh], so i could switch batteries when the first went flat, its looking like im gonna have to get used to the idea of a maximum of 30mins. Is there no way of achieving 1hour ? no way of improving the cooling of the motor whilst its been used ? 

Easy, 2 Boomerangs!  You can never have too many Boomerangs.

I don't know, I have checked temps after 30mins run time (I think I got closer to 40mins when the batteries were new) and they are hot but nowhere near too hot.  I have had a motor stinking and far too hot after a 5min race and these cars are nothing like that.  Mine are ballraced though, that will help

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Lipo batteries seem to give longer run times in my experience and also give a bit more punch, but they require a bit of TLC.

I know nothing really I just suck it and see, my son has an FTX Carnage standard brushed jobby and we run 2s lipo on that 4000mah it lasts about 40 minutes before the alarm gets triggered on a similar nimh its about 20 minutes. I have a huge truck that has a big brushless motor and ESC and weighs about 4 kilos my last run time on a car park 4000mah 4s it lasted 35 minutes and was being pushed hard, I now have a 5000mah battery for it but yet to test it.  

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13 hours ago, MrDGH111 said:

Im learning quite a lot here, i was hoping for an hours worth of non stop fun, i bought 2 batteries [4400mAh], so i could switch batteries when the first went flat, its looking like im gonna have to get used to the idea of a maximum of 30mins. Is there no way of achieving 1hour ? no way of improving the cooling of the motor whilst its been used ? 

A brushless motor will give you more power for less heat as they are far more efficient, I run a 8.5T 4000KV in my hotshot, which is heavier than your boomerang, I tend to only run it for 15-20mins tops, but I can pick it up after that and the motor is barely warm. With a  13.5T brushless motor and a 2S LiPo you will probably break the car before the battery goes flat.

 

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1 hour ago, novicelad said:

Lipo batteries seem to give longer run times in my experience and also give a bit more punch, but they require a bit of TLC.

I know nothing really I just suck it and see, my son has an FTX Carnage standard brushed jobby and we run 2s lipo on that 4000mah it lasts about 40 minutes before the alarm gets triggered on a similar nimh its about 20 minutes. I have a huge truck that has a big brushless motor and ESC and weighs about 4 kilos my last run time on a car park 4000mah 4s it lasted 35 minutes and was being pushed hard, I now have a 5000mah battery for it but yet to test it.  

Wow 40 mins on a 4000mah cell? I can only assume you must have the throttle limited a lot and/or in a very small space. 

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4 minutes ago, Losi XXT-CR said:

Wow 40 mins on a 4000mah cell? I can only assume you must have the throttle limited a lot and/or in a very small space. 

That's the efficiency of brushless, combined with the voltage stability of LiPo. Nimh really is very old hat now. I can run my TXT-1 round on a 1/8 brushless motor for 20-30 mins on a 4000KV 3S battery, and I stop because I've had enough, not because the battery is flat. I don't think I've reached the low volt limit on a LiPo, normally the car breaks or I get bored before that happens. (That's why I usually go bashing with at least 3 models ;) )

 

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3 minutes ago, Losi XXT-CR said:

Wow 40 mins on a 4000mah cell? I can only assume you must have the throttle limited a lot and/or in a very small space. 

Admittedly this is in my garden lots of stop going, it surprised me too! My big truck surprised me more but then I suppose a big  motor in a car park is not likely to be very stressed 

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2 hours ago, MadInventor said:

That's the efficiency of brushless, combined with the voltage stability of LiPo. Nimh really is very old hat now. I can run my TXT-1 round on a 1/8 brushless motor for 20-30 mins on a 4000KV 3S battery, and I stop because I've had enough, not because the battery is flat. I don't think I've reached the low volt limit on a LiPo, normally the car breaks or I get bored before that happens. (That's why I usually go bashing with at least 3 models ;) )

 

They said it was a brushed Carnage. 550 motor and 15 Turn iirc. In a 4wd truggy/stadium. 

I have LiPo’s and brushless and brushed motors. Never got close to that sort of run time. Good quality 4200mah and a 13.5 brushless in my Konghead does about 20 mins. 

8.5 4100kv brushless in my 2wd Turnigy SCT2 about 12-15mins on a 4500mah. 

Under 10 mins in my Arrma Raider XL BLX. 

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2 hours ago, Losi XXT-CR said:

They said it was a brushed Carnage. 550 motor and 15 Turn iirc. In a 4wd truggy/stadium. 

I have LiPo’s and brushless and brushed motors. Never got close to that sort of run time. Good quality 4200mah and a 13.5 brushless in my Konghead does about 20 mins. 

8.5 4100kv brushless in my 2wd Turnigy SCT2 about 12-15mins on a 4500mah. 

Under 10 mins in my Arrma Raider XL BLX. 

 

7 hours ago, novicelad said:

Lipo batteries seem to give longer run times in my experience and also give a bit more punch, but they require a bit of TLC.

I know nothing really I just suck it and see, my son has an FTX Carnage standard brushed jobby and we run 2s lipo on that 4000mah it lasts about 40 minutes before the alarm gets triggered on a similar nimh its about 20 minutes. I have a huge truck that has a big brushless motor and ESC and weighs about 4 kilos my last run time on a car park 4000mah 4s it lasted 35 minutes and was being pushed hard, I now have a 5000mah battery for it but yet to test it.  

This was what I was thinking of.

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4 hours ago, MadInventor said:

 

This was what I was thinking of.

No worries. Although I personally struggle to comprehend 35 min runtimes on such a Vehcile. 

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10 hours ago, Losi XXT-CR said:

No worries. Although I personally struggle to comprehend 35 min runtimes on such a Vehcile. 

I was just running it round on full throttle in a field without using brakes or acceleration much. Plus the big 1/8 motors are usually only about 2000Kv, which means lots of torque from the bigger motor and lower rpms, which all contributes to less heat and energy loss. I also had the timing turned down to zero on the TXT-1, so after running for 20-30mins the motor temp was barely above ambient.

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2 hours ago, MadInventor said:

I was just running it round on full throttle in a field without using brakes or acceleration much. Plus the big 1/8 motors are usually only about 2000Kv, which means lots of torque from the bigger motor and lower rpms, which all contributes to less heat and energy loss. I also had the timing turned down to zero on the TXT-1, so after running for 20-30mins the motor temp was barely above ambient.

My TNX motor doesn't get warm even after a hard run, its a 4068 2050KV  to feel the warmth you need to wrap your hand around it, maybe we should do a run time thread different configurations batteries etc 

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Going back to the identifying the problem, I would simply undo the two bolts holding the motor and roll the car on the ground without any motor attached.  That is the easiest way to check what @waterbok said about thickened grease.  If it rolls only a foot or two, you have to clean the whole thing. 

If it can roll 4-5 feet with relative ease, it could be a gear mesh problem.  Hotshot series (Boomerang and Bigwig, etc) have a unique system of using metal plates to keep the correct distance of the pinion.  If you use an incorrect combination, you have a gear mesh problem.  So, count the teeth of the pinion and match the combination of plates as shown below. 

Also putting in ball bearings is generally a good idea.  It will improve as much as 15% of runtime.  

UFHFGJc.jpg 

 

 

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On 17/03/2018 at 12:33 AM, Juggular said:

Going back to the identifying the problem, I would simply undo the two bolts holding the motor and roll the car on the ground without any motor attached.  That is the easiest way to check what @waterbok said about thickened grease.  If it rolls only a foot or two, you have to clean the whole thing. 

If it can roll 4-5 feet with relative ease, it could be a gear mesh problem.  Hotshot series (Boomerang and Bigwig, etc) have a unique system of using metal plates to keep the correct distance of the pinion.  If you use an incorrect combination, you have a gear mesh problem.  So, count the teeth of the pinion and match the combination of plates as shown below. 

Also putting in ball bearings is generally a good idea.  It will improve as much as 15% of runtime.  

UFHFGJc.jpg 

 

 

Very interesting !

Well I did as most were recommending and pulled to pieces the gearboxes, found nothing obvious, no damage, no wear, not even sticky grease in fact it all looked very nice (I can’t believe after all this time but it’s true), the grease even looked (to me) to be adequate. Anyway whilst it was in pieces I cleaned and re-greased, I didn’t go crazy with the grease (I didn’t have any Tamiya grease, I used what I had - White Lithium). I also removed all 4 wheels and inspected, cleaned and re-fitted (didn’t use any grease here, thought it’d attract too much dirt ???).

I,ll  be honest I don’t think I’ve fixed anything, but I have to go buy another motor again to find out (this will be number 4 !).

BUT…

Now reading Juggular‚Äôs suggesting ‚ÄėA Light Has Come On‚Äô I remember when I took off the first blown motor (the original from 1986) I found these metal plates laying on the bench,¬†I‚Äôll be honest I don‚Äôt know what order they were in as to begin with I didn‚Äôt even know where they‚Äôd come from, I quickly realised but on re-fitting the new motor I ‚Äėguessed it‚Äô and also too for each other new motor after, this could be my problem right here couldn‚Äôt it ? Now I have the detailed info I just need to count the teeth on my pinion and hold my breath !

There are only 3 plates though, so either it only ever had 3 or I lost one during the first strip down, I’ll have to get one made up somehow this weekend I guess, I’ll keep you posted.

Thanks Juggular, you’ve given me some hope.

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If you haven't thrown away the blown motors, the lost one could be magnetically stuck to a motor.  

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