H&R Hawk Motor

[Audi1]

I've posted this message to a couple of different forums today and wanted to get the opinions of those here on HRW. It's a little confusing to me; here it is.

I've been using the H&R Hawk motor (rated 18.0k rpm @ 12V) for about a year now in several different types of cars; NASCAR to resin body sports car and in between. I like the motor. But recently I've noticed a general drop-off in the rpms of the motor both before and after break-in. Whereas I used to get motors that turned 17.8-18.2k pretty routinely after break-in, recently I've been getting motors with break-in rpms in the range of 16.8-17.3K. The break-in procedure is the same in all cases and when I go back to the older motors, they still spin at the rpm that I originally tested them at. I messaged HNRRacing on this, but I haven't heard back from them yet. I have data from about 10 of the newer H&R Hawk motors and from 2 suppliers, so I think this rpm drop-off is real and not a fluke (or it's just horribly bad luck on my part).

At this point I'm sifting through $10 bills at a pretty good clip; in search of Hawk motors that spin at their rated rpm.

Has anyone else seen this drop-off in either the out-of-the-box or the break-in rpms on this motor?



Allan

[HomeRacingWorld]

I haven't. I don't have a rpm tester though. Just going by the cars performance. Some older models are the same as new ones I have just built.

[Audi1]

You need a pretty good sized straight to use the full rpm range; even with an electric motor, so it may not be showing up on your tracks. I measured another one after break-in last night 16.8k rpm. Disappointing. I guess it may be lot-to-lot inconsistency................... Too bad, I liked the motor because of its torque.

Allan

[Mitch58]

What I like most about the H&R motors is how smooth they are throughout the entire throttle range. I haven't noticed any variation in RPMs but my track is only about 30' with a 10' straight section.

[nhdungeonracer]

Allan, do you test the rpm's on your motor before you break them in?

I've never really bothered to take the time to break in motors. I usually just put them in a car and start driving. More fun that way :D

[DixonJohn]

I figure the problem is the fact that they are Chinese arms.They will use whatever is in the factory at the time. As a former commercial racer we had these problems a few years back with the Parma Deathstar. It got down to looking at what color the wire was to get a decent motor. Same problem with the Parma super 16 now. The coms are coming apart after a few runs.They ungodly fast but your changing motors every few runs

[Audi1]

[mikeinclover]

I will make sure I send some good ones in your order Alan.

[Mayberryman]

[mikeinclover]

Bench test them.
Mike

[Audi1]

That's what I was hoping to hear..........Thanks!. :banana-dance:

Allan

[Rleog]

[Audi1]

Hi Bob,

I don't think it has, but am not certain of that.

I would not assume a corresponding increase in torque, the two; rpms and torque, often run counter to each other. Higher rpms can mean a drop in torque.

Allan

[McLiams]

[Audi1]

Thanks for the information, Mc. What type of instrument(s) are you using to measure the rpm of the motors? Is it a stroboscopic measurement (laser tach with reflective strip wheel on the motor)?

I ask because I have received a batch of H&R Hawk motors recently that were tested on a different type of instrument and they all measured greater than 18,000 rpm; one as high as 21,500 rpm. Torque measurements were also very close to spec on all motors tested. When I tested them, the 21.5k motor tested out at 17,500 rpm. So, it seems that the measuring system is key to determining if these motors reach spec, or not. Not a surprising outcome.

I have also received H&R Hawk motors from 4 different distributors and, using the testing apparatus that I have described, all of them show significant variability, with only one testing out at 17,500 rpm; the rest lower, some significantly lower.

I want to point out that if anyone is involved in racing where all of the cars are powered by the H&R Hawk motor, then this testing difference that we're picking up will be, virtually, inconsequential. However, if you're going to use the H&R Hawk in racing against other "18,000 rpm" motors, then having a motor that's below spec; in some cases significantly below spec, won't do you any favors on the race course; particularly if that course has long straights.

I would like to see H&R Racing respond to some of the messages that I've sent to them about the rpm performance of this motor, but so far, I haven't been able to hear back from them.

In closing, I realize that the use of the H&R Hawk is a choice; one among others that are available to me. So, I don't plan to spend anymore time describing this rpm issue. But, as I said in my original post, I like the H&R Hawk specs for racing in the 18,000 rpm motor class; particularly the torque. Who knows, perhaps its just the pretty blue color. ;)

Allan