Pershing lack of speed

[philipat]

I was hoping to keep most of the torque, which is why I like the sound of these "zoom 400s".  Faster is actually what I want for scale speed, since I'm trying to put these into my Bulldog.  I have RC Command's steel gearboxes (same gear ratio as the standard plastic gearboxes) and according to Swathdiver's spreadsheet, I can't even get full scale speed without a 480, which seems to be a risky prospect even with a cooled RX-14.

So, these zoom 400s seem like a good alternative.

[wibblywobbly]

The Protech Zooms that I have are not brushless. I think Midland Helicopters sell them, its worth giving them a call as they are very knowledgeble people on the topic of motors. Pete is correct about the Speed v. Torque. It's always a trade off. It's the same for any engine, a low revving diesel engine will have more grunt than a high revving petrol engine. The only way to get the torque back is to lower the gearing, at the cost of speed.

If you want to know what 'slow' looks like, try putting HL white cap motors in a 13lb Elmod powered Tiger with standard metal gearboxes. : (

[philipat]

yep...I understand the trade-off between the faster motors and the torque.  I'm still trying to keep some of the balance between the two.  I think it was your mention of using these versus Graupner400s in a helo and getting better low-power performance in the Protech versus the Graupners in your helo.  So, I figured that I'd like to experiment with these first.

I did some more digging and found these.  Are these the Protech 400s that you have, only in a 7.2V instead of the 6V?  (I'm on the wrong side of the pond to call Midland  :-\ ).  http://www.mcmracing.com/catalog/product_info.php?cPath=200000_202000&products_id=400239&osCsid=3293180ae7343523072200da2e54882a

Thanks for the help.

[wibblywobbly]

I will see if I can find a link to the ones I have and get back to you.

[wibblywobbly]

Here we go:

http://www.modelhelicopters.co.uk/acatalog/HeliSprs_Zoom.html
Part Number: T0500.020 : 380 Motor Assembly

[philipat]

roger...thanks for the help.

[971wright]

Hi Guys dont use 6v motors they eat batterys for fun .run time will half what you get with 7,2 v.


regards pete

P.S take a look at swathys gearbox & motor chart you can play around with it entering different combanations of motor to gear ratio,you can down load it from the download section ,If you dont have microsoft exel you can down load office .org its free and you use that for exel files .

[philipat]

good advice...thanks.

I've been looking at that spreadsheet.  The link from wibblywobbly looks like the motors that come with RC Command's steel gears.  I have those and they work well, but not what I'm after for my Bulldog.  Based on the spreadsheet I need to go with 480s and a 14-tooth pinion to get top scale speed.  I'll have to debate that with myself and how much torque I want to loose.  :-[

Anyone have a good idea of the type of torque from a 480 with the standard gearbox?

[971wright]

Hi 480 motors have plenty of torque .but you will be pushing the board to the limit you will have to fit a fan to get rid of the heat .I run them in a Tiger it hasnt blown the board yet but it does have a fan on it .

regards pete

[wibblywobbly]

Pete - Are you running 480 motors off an HL board? Is that a 14 or an 18. I have been trying to find someone who has done this for a long while. Which motors are you using?

Tackle - Trust me, those Protech Motors are amazing. If I can find the time I will swap them into my Bulldog and post a video on You Tube, I will do one with the Graupners that are currently fitted as well for comparison. The Bulldog will climb mountains as if they aren't there and zips around no problem.

Rob G