hahaha yeah man!! you just buy and fly!!! but when you want to upgrade you need to take a look at a few things.. .if you dont you might end up taking your plane home into pieces the first time you fly it!

Originally Posted by Retiredtech

...I’m wondering if the motor-mount surface on your new fuselage is the same angle as your old one.

Good luck.

RT

Well, one was from Atlanta Hobby and the replacement was direct from HH. Both around the March time frame, so I would think they are similar.

I have a DX8 too, so I can mix in elevator. Just seemed strange that it changed. Guess I have to blame it on the firewall because nothing else changed.

Not to stoke up the kv versus watts discussion LOL but harrow made a good point and i am mentioning this for the person that originally asked about the g15

----- a lot of cheap motors have the kV rating stated wrong----

When i bought this motor i thought it would be the same as the eflite p15,since it was listed the same specs and is a direct copy,i was hoping to be able to prop the corsair up a bit but since this is such a high kv i cannot go above 10x7 on 4s.when i put the Power 15 on the t28 i only had the 40 amp pro lite laying around at the time and propped it to that with 4s which came out to 39 amps,when i ordered the g15 i went with the bigger 60amp turnigy plush,and thought since the p15 is pulling 39 amps i will be able to prop this up a bit and still have some legroom,and wound up at 62 amps with the same setup that should be pulling 39,i did a search for any info on the g 15 and did not find anything about such high amps,maybe it was just my motor who knows,but in hindsight if i would have know it would have pulled so many amps with such a small prop on it i would have went with the lower kv motor,i would love to know why this is pulling so many more amps,than the same spec eflite p15,if anyone has the answer i am all ears,or kv LOL

Ron

If anyone is interested in the Spektrum DX8 mixing for Throttle>Down-Elevator to help offset the unwanted ‘climb on full throttle’ problem, this is what worked for me.

Set the mix as follows:
THR > ELE
Rate: 5% (Started here, then adjusted for desired full-throttle climb-rate)
0%
Offset: 0%
Trim: Inh
Sw: (A switch that works for you)

Fly the Apprentice at half-throttle and trim the elevator for level flight. Switch in the Mix and set the Mix ‘%’ for the desired climb rate at full throttle. This will have no throttle-to-elevator Mix until approximately half-throttle, then down-elevator will be proportionally applied when the throttle is increased from half-throttle to full-throttle.

CAUTION: If you want to test this setup before flight, either disconnect the motor or program in a motor-cut!

RT

Originally Posted by BlinkguY

hahaha yeah man!! you just buy and fly!!! but when you want to upgrade you need to take a look at a few things.. .if you dont you might end up taking your plane home into pieces the first time you fly it!

What are you talking about??

RT

Originally Posted by snoopy3440

if anyone has the answer i am all ears,or kv LOL

Ron

The higher rated ESC will have a lower resistance which means you will have less voltage drop and should therefore see a slight increase in power and current. But surely nothing like an increase from 39 to 62 amps?

I can think of two other explanations. One is that you have a higher than spec 'kV'. If a lazy worker on the production line did one or two less turns when winding the motor, then that would give you a higher 'kV'. (Which as we all know would spin the motor faster and draw more power and current. ) The other cause could be if the motor was seriously inefficient due to very poor quality or undersizing of the laminations, which would draw more current but not give you more power to the prop, instead the extra amps just heating up the motor.

The way to help diagnose is to measure the RPM at full throttle with each motor and see if you are actually getting a genuine increase in RPM output for the extra amps being drawn. Probably there is a combination of all 3 effects (low resistance ESC, higher than spec 'kV', and less efficient motor) going on.

P.S. An interesting thing to try would be to measure the RPM of the original motor at full throttle (your 39 amps case) and then put the new motor back on and increase the throttle to get the same RPM (recharge the battery first to keep things equal), and see if it is drawing much more than 39 amps.

Originally Posted by Retiredtech

I make a motion we call a truce on this Kv issue.

Forums are such a hard place to have discussion on technical things. I've seen people with identical views argue because it can be difficult to explain things. Glad it's all been kept in good spirits 'cause so often I've seen it go the other way. Cheers and good will to all!!

Originally Posted by MX5Seeker

Any other advice?

It would be somewhat of a coincidence for your rubber bands to go soft the same day that you switch fuses. My guess is that the motor angle is up slightly, and the extra washer idea is exactly what I would have done.

The THROTTLE-> ELEVATOR down mix is also fun to play with just as Retiredtech explained. Not sure there is anything else you can do.

Thanks gentlemen. I think I will start with the washers, then try playing with the mixing.

There's an old problem, of misalignment, that might be apropos here.

http://www.rcgroups.com/forums/showp...postcount=1170

It relates to using Apprentice replacement parts.

Are you seeing the same thing?

Dave

Hey Harrow

Thanks for the explanation,it always bugged be since i bought this setup and never new why it pulled so many amps,i threw it in the corsair and it flew fine and that was good enough for me,but the amp draw is just crazy.so i guess its time to do some experimentation, when i get a chance i will do the things you recommended i was also curious if the 60amp plush had any effect on it so i will pop that on the p15 that's pulling 39 amps and see what it does.just give me some time i will post the results as soon as i can,hopefully i can finally get to the bottom of it,i asked a lot of people and no one really had an answer other that what i thought, that it was just a higher kv motor mislabeled,but your post makes a lot of sense,Thanks

Ron

We had several guys locally that tried to replace a power 15 with a g15 and found it just wasn't the same motor. The only way they could get the amp draw down was by dropping pitch down an inch or so on the prop. That let the motor run up to speed without overloading it and the amps came down, but then it didn't have nearly the speed that the power 15 had with the larger pitch prop. But you need to use a tach to see what is going on to make sure you are not overloading the motor with too much prop. Higher kv requires less pitch with same motor size. Too much prop is like putting a brake on it. It will draw high amps then.

Pugsam,

No, mine does not have an alignment problem.

Originally Posted by bobly

We had several guys locally that tried to replace a power 15 with a g15 and found it just wasn't the same motor. The only way they could get the amp draw down was by dropping pitch down an inch or so on the prop. That let the motor run up to speed without overloading it and the amps came down, but then it didn't have nearly the speed that the power 15 had with the larger pitch prop. But you need to use a tach to see what is going on to make sure you are not overloading the motor with too much prop. Higher kv requires less pitch with same motor size. Too much prop is like putting a brake on it. It will draw high amps then.

That is the same problem i had with g15,my t28 is running the p15 and corsair is running the g15 both with mas 10x7x3,thats what i said earlier they both feel the same in the air,if my t28 had a bigger esc,a 60 amper i could prop it up a bit and walk away from the corsair,when i got the g15 i bought the 60amper for it to walk from the t28 but like you said i had to prop it down to keep the amps lower,guess you get what you pay for,they both pull good and i am happy with the speed dont think i want much more on these,but it struck me when i saw the amp draw the g15 was pulling ,gonna run some test later and see if we can find out whats going on

Ron

Originally Posted by bobly

We had several guys locally that tried to replace a power 15 with a g15 and found it just wasn't the same motor. The only way they could get the amp draw down was by dropping pitch down an inch or so on the prop. That let the motor run up to speed without overloading it and the amps came down, but then it didn't have nearly the speed that the power 15 had with the larger pitch prop. But you need to use a tach to see what is going on to make sure you are not overloading the motor with too much prop. Higher kv requires less pitch with same motor size. Too much prop is like putting a brake on it. It will draw high amps then.

ok guys.. so what the plug and play replacement option from hobbyking? did you find out?