Dave Brown spinner fit with APC prop

[RknRusty]

I have finally gotten my newest stunt ship balanced and trimmed to suit me, but there's one problem. I used a weighted acorn nut rather than a spinner on the nose. There are occasions that I need to use an electric starter, and the silicon cone doesn't fit the nut. So I searched out this Dave Brown 2" aluminum spinner:
http://www.ebay.com/itm/NEW-Dave-Brown-2-Standard-2-Blade-Aluminum-Spinner-S220-/390947367276?hash=item5b0647696c
I've never used aluminum before and wondered how much filing and grinding I might have to do to get it to fit over a fat APC 10.5x4.5 prop and hub. I already have a Dave Brown adapter nut.
http://www.ebay.com/itm/331217694085

I just don't want to ruin a good aluminum spinner trying to shape it.
Thanks,
Rusty

[Motorman]

You can do it. Just mark out your cut on both sides and only take a little at a time as you fit the prop.


MM

[Mark Scarborough]

Typically I cut only one side of the opening, to preserve balance and symmetry

[George Truett]

It seems hit or miss whether the opening fits a given prop or not.  Tru-Turn will modify their spinners for you, don't know about the DB.  It's not too hard, I make a paper template from a spinner that does work or a guess on what it will take.  As Mark said, pick the front or back of the existing opening and work the same direction both sides and as MM said, work slowly.  I use Dremel sanding drums starting with the small size in a coarse grit and working to the finer grit.  Expect to go through a drum or 2.

[RknRusty]

Typically I cut only one side of the opening, to preserve balance and symmetry

Yeah, me too.

...I make a paper template from a spinner that does work or a guess on what it will take.  As Mark said, pick the front or back of the existing opening and work the same direction both sides and as MM said, work slowly.  I use Dremel sanding drums starting with the small size in a coarse grit and working to the finer grit.  Expect to go through a drum or 2.

That's a good idea. I have plenty of the Great Planes spinners that are cut just right for tracing a template. Those come with pre-stamped guides in the plastic to help you get in the neighborhood.

Thanks for the replies, guys.
Rusty

[Motorman]

If you've never done an aluminum spinner before, watch out that it changes section. It gets thinner toward the pointy end. When you're grinding on the thick part and move to the thin part it cuts very much faster!!

MM

[RknRusty]

Thanks for the heads up on that, MM.

[Tim Wescott]

This should go pretty quickly with a pair of round files -- both 1/4" or 3/8", one bastard cut and one smooth cut.  Rough it out with the bastard cut, then smooth.  If you're really picky try to find an extra smooth file or wrap some 400-grit wet-or-dry around a dowel.

(Note: I have a cheap mill-drill machine.  I never used it for what I bought it, but it's dandy for milling out spinners to fit APC props.)

[Steve Helmick]

I'd suggest making the cutout big enough that you can still try other propellers. Making a template out of 3x5 card stock should be some help. Also, visit the Tower Catalog and review the replacement drive cones. What you can get depends on the brand of starter you have. Right now, I'm using a cone designed for needle nose spinners (I think it's silicone), because I'm using an "Ultimate" Tru-Turn spinner on the current dog. This gives a really good grip to spin over my OS .46VF AAC. Running an 18v. Makita battery on the starter makes it pretty zippy! Steve

[RknRusty]

I'm even looking forward to the aesthetics of it, though function was my only reason for buying an aluminum spinner. It'll match my silver colored graphics on the wing.

And dang, I'm disapppointed. After Sunday, when I finally hit the magic trim combination I've been trying to get for its first 25 flights, I'm all jacked up, dry flying in the house, daydreaming patterns, itching to go, and found out it'll be a week from today before I get to fly again. I was able to repeatedly do things I've struggled with since I was a beginner. This is such a great plane, and Huntersvile is 4 weeks away.
Bouncin off the walls,
Rusty

[RknRusty]

I'd suggest making the cutout big enough that you can still try other propellers. ... Running an 18v. Makita battery on the starter makes it pretty zippy! Steve

Steve, my lead-acid battery is too darn big. With the "Help" of an Interstate Batteries salesman, I seriously overestimated the a/h I needed for a few 3 second bursts of power during a day of flying. It's like carrying a brick around. I think I might go get a 50% reduction in cranking amps and lighten my load a little.
Rusty

[Steve Helmick]

I've been able to use my Sullivan/Makita setup for only 4 flights so far this year, but I really like it a lot. No wire to worry about. Not real cheap, especially since I didn't own any Makita stuff, but I bought the whole Makita 1/2" drill kit and also like it a lot. The batteries are 3ah, but 4ah batteries are available. Meanwhile, I take the two Makita batteries out of the drill kit and put them in a small Rubbermaid tub to keep them safe from shorting and abuse. I haven't discharged one significantly yet in either starting engines or driving decking screws into the fence.   

The one picture shows the adapter manufacturer info, who says he really prefers the Hobbico starter, and that the adapter installation is easier. My starter was an early production one, and I had some problems with the installation because of that, but I got it sorted out and it works nice! His interest is actually R/C Helicopters. The adapter is $50 including postage, and service was quick. Ask for the instructional .pdf to be sent to your email when you order. He takes PayPal, which also works with major credit cards.  Steve   

[RknRusty]

That's pretty cool. I guess the adapter steps it down to 12v? Maybe not, since there's no chance of even getting the motor hot if used as intended. 18v straight to the motor, I wonder if the a/h goes up. Maybe 'll put that on my list to Santa.
Mine is probably a Hobbico.

Thanks, I like it.
Rusty

[Mark Scarborough]

I bought one of the systems from tower that bolts to the starter and serves as a stand, it has an enclosed gel cell battery but its way to small to be effective. So I trashed the battery and stuffed a 4S 2700 LiPo into the carrier, its 16 volts and it will start a dead racoon if I ask it to, its got mojo!!

no reduction in voltage, it just spins that bad boy in a hurry, it also charges in less than 35 minutes. The pack is one that is no longer suitable for flight, it had lost its capacity so I repurposed it

[Steve Helmick]

That's pretty cool. I guess the adapter steps it down to 12v? Maybe not, since there's no chance of even getting the motor hot if used as intended. 18v straight to the motor, I wonder if the a/h goes up. Maybe 'll put that on my list to Santa.
Mine is probably a Hobbico.

Thanks, I like it.
Rusty

Straight 18v., so really zippy. No smoke so far! Low duration run-time makes it a non-issue, and the wires are plenty big, because now they're real short. As I recall, the thing that made the Hobbico starter more desireable was a better switch design...but then again, I'd just replaced the switch on my Sullivan, because it didn't always shut off. Now, the "on" is just a wee spot under the tip of the index finger. Previously, the whole switch pad would turn it on. I kinda like the new switch, but it is "different". I got it from Sullivan, of course.  Steve