Testors Galax IV & how to remove the motor backplate?

daddyo Sat May 23, 2020 2:17 pm

I bought a great condition Testors Galax IV hovercraft but the spring starters broken. I broke my original Galax when I was a kid trying to fix the same thing, so I'm trying to avoid that this time around. I've tried freezing and that does loosen it up so it'll rotate, but it just won't pop off by hand. I think I'd rather buy an electric starter than to have it break. I couldn't seem to find any other hints on how to do this. Any suggestions?

BTW I bought this also because I wanted to see if I could actually get a Testors 049 to actually start more than once. They seemed like the worst motors when I was a kid, but see in the forums that some people think they're easy to start.

Testors Galax IV & how to remove the motor backplate? Hoverc10

Testors Galax IV & how to remove the motor backplate? Testor10

Found instructions here: https://www.coxengineforum.com/t9743-o49-cox-question

Marleysky Sat May 23, 2020 3:21 pm

You just have to “pop” the backplates out of the crankcases. They’re tougher than you think!

Testors Galax IV & how to remove the motor backplate? C3ab3510

Testors Galax IV & how to remove the motor backplate? 970b1910

It’s been a while since I’ve disassembled a spring starter, I think I just removed the broken spring and manually started them. Thought I had instructions somewhere, l’ll have to keep looking.

roddie Sat May 23, 2020 4:20 pm

Yes! I was thinking the same as Rene (Marleysky).. regarding removal/re-installation of an engine. I don't know what the design-propeller size is. Yours may be noted near the hub.. as are Cox propellers. The Testors aero-propeller's hub-hole receives the 6-32 threaded output/crank-shaft on the Testors/McCoy engine. A 6-32 threaded aluminum spinner-nut would be needed for an electric starter to be used effectively.

I have instruction sheets for the model, but am missing the replacement/spare-parts page. The propeller size/spec. would be noted there.. if you needed to swap-in another engine having a working spring-start.

I probably got these images from an eBay auction.

Testors Galax IV & how to remove the motor backplate? 27006010

Testors Galax IV & how to remove the motor backplate? Manual10

Testors Galax IV & how to remove the motor backplate? Page210

Testors Galax IV & how to remove the motor backplate? Page310

Testors Galax IV & how to remove the motor backplate? Page410

Testors Galax IV & how to remove the motor backplate? Page510

Testors Galax IV & how to remove the motor backplate? Page610

Here's an image of the decal-sheet.. should you want to reproduce them.

Here's some images of the Galax IV engine..

Testors Galax IV & how to remove the motor backplate? Galax_13

Testors Galax IV & how to remove the motor backplate? Galax_14

Hope that you're able to get the model running. Hovercrafts have always amazed me! Thumbs Up

daddyo Sat May 23, 2020 6:57 pm

I've tried all week to pop this thing out with all my might, it just won't go, only spins at cold. It feels like I'm going to break the plastic if I were to have any more strength! Marleysky, what's your technique, rocking it or just pulling, how were you able to do that?

Someone mentioned to me the idea of a specialized tool to do this, like a very shallow pickle fork / ball joint separator like tool. Makes me wonder if there were such a thing for these motors, but couldn't turn anything up on Google.

I just happen to have a small aluminum spinner that I can thread to fit. Otherwise adding the spring starter sounds like a perfect long-term solution. I'm going ebay hunting... Maybe someone here would sell me one? It would need to have a pretty large inner diameter of 0.96"+, and a hoop or enough material to go around the cylinder head. I have to wonder if Cox had a patent on the spring starter, causing Testors to come up with this nutty thing that commonly breaks.

I will definitely put up a video of this thing flying, and if it's running well it's going over a pool.

I've a bag of Estes motors, might be pretty funny to see one on the back of this thing. I'm sure I would have done it when I was a kid, if that one ran more than once.

BTW the prop is unmarked.

Oldenginerod Sun May 24, 2020 4:27 am

I've never had any real problems popping the back off a Pipe Bomb, plastic or pot-metal models. It may be possible to wedge a blade of some sort carefully between the boss on the front of the plastic part and the casting that retains the cylinder. Looks like the most solid part. Having said that, all I ever do is pull, twist and bend in one action and it always works for me.