Well Andy, that ought to keep the motor cool. It looks good too.

Andy,

That looks great, but if you are gonna make those struts betweeen sections that thick, why not angle them to create a fan effect when rotating?


G

Any other practical ways to cool the motor, such as the use of thin alum sheets (as part of the firewall) to conduct the heat away?

Um......thanks for your comment
maybe l design some angle to "section support" will be help for fan effect.
But i am worry about the mold production will be difficulty.
then it's will make cost high then fan effect.
[&o]

I am running prototype aluminum heat sink soft mounts with Pletty 30-10 Evo's in my two Leviosa's, with cut-nose spinners. Removing the nose of the spinners lowered the motor outer can temps by ~ 25 deg F, and the addition of the heat sink mount lowered it another 20 deg F, to ~ 130-135 deg F (from a Masters flight flown in hot, 100 deg F, windy weather). Interestingly, I measured the temp of the heat sink motor plate after a typical flight at ~ 145 deg F, which was 10 - 15 deg F WARMER than the motor case! I also measured the temp of the rear motor mounting screws and they were about the same as the temp of the heat sink plate (normally they're much hotter than that), so there's a lot of thermal heat transfer from the motor core into the heat sink plate.

BTW - The origination of the cut-off spinner nose was initially tested last fall by SoCal Advanced class pilot Mike Greear. I'm not sure where the idea came from, possibly an extension of Jim Oddino's successful use of an undersized spinner on his Abbra over the last couple of years (which also works well). I do remember a discussion last year with Greg Frohreich about the idea, but don't recall if it was his concept or Mike's.

Thanks. That info is useful.

May I ask the size of the heat sink plate? What does it look like?

?? But this concept has been used for years, all over the world....

Regards,
Magne

It's a 0.125" thick aluminum plate that the motor bolts to (rear mounted) and 4 rubber isolation mounts fastening it to an aft carbon/plywood laminate firewall. It's very similar to the larger (gold colored) soft mount I currently sell, just with a wider mounting pattern and a much stiffer aluminum plate (the rubber isolators are identical). Besides the benefits of the vibration isolation and the thermal dissipation, it's a lot easier to make thrust changes at the rubber isolators vs. shimming the backside of the motor with washers or tapered pieces of plywood.

Once I get some more time on it I'll have some produced and offer it for sale on my website. So far though, it's working really well.

Really?

By whom, where, and when?

Pics?

I think first time I came across a spinner with a central cooling hole was about 20 years ago when flying electric gliders.
Manufacturers such as Aeronaut, Graupner etc. offered several versions.
Everything we see here is just variations of the theme.
Plettenberg have offered their specific version for som years now for the Xtra, Terminator and Predator series of motors, previously in aluminium, now in carbon.
Mejzlik offer some carbon spinners.
PÃ¥l Kvaloy here in Norway has been flying for a few years now with a cut-off plastic spinner, seems to work well. (But I have never heard him claim it was his idea, probably because it wasn't.)
Etc, etc.

Magne

I did the cutting with a Dremel cutting wheel mounted on the drill press. Here are the steps.

1. Adjust the platform to the right hight so that the cutting line is at the wheel level.
2. To cut, just gently push the spinner to the spinning cutting wheel.

I found the plastic material on GP's spinner is pretty tough. It can easily break the abrasive cutting wheel if the spinner is pushed too hard against the wheel. So use caution.

I cut mine with this method in about 5 minutes.

One of the problems you may be having it that even if you put that drill press on its highest speed, it is still about 1/4 what a Dremel tool turns. Those abrasive wheels work better at higher RPM.

I use the Dremel fiberglass reinforced #426 cut off wheel in my drill press to do the job. No Problem!

J

http://www.mytoolstore.com/dremel/brshwhls.html#wheels

Yes, some better and sharper cut wheel can be used.

I do not feel the abrasive cutting wheel cuts that slow on dress press. Just take the time. The benefit would be precision cut. Actually, you can use this method to help make pilot cuts and then enlarge them to shapes such as those of water drops shown in F3A Unlimited's CF spinners.

Andy, that rear-mounted exhaust fan is clever! Have you determined if your power consumption has increased with use of this small fan?