ricknkim

I have a 60 size CG Super Chipmunk that I am currently covering. The instructions call for a 2 1/2" spinner for the nose. I am putting a YS 91 in the front. I bought an aluminum 2 1/2" spinner for it, but the holes are too small for the prop sizes for the YS 91. I asked the guy at my LHS about it and he said just to ream out the holes to make it fit the prop size. Should I do this or buy a bigger spinner?

RCKen

My Feedback: (9)

ricknkim,
no, the spinner you have is fine. Do as your LHS recommended and trim the spinner to fit. If it won't fit on the prop shaft then drill the hole out to fit. If it won't fit over the prop then use your dremel to enlarge the cutouts to fit over your prop, just try to remove the same amount of material from both cutouts in order to keep the spinner balanced.

I've never built the CG Chipmunk, but I've built other kits with a cowl on them. Usually the cowl is formed with a specific spinner to match it. If you go with a bigger spinner it's going to break the lines of your cowl/spinner fit.

Hope this helps

Geistware

My Feedback: (16)

If you can find a drum that will give you the proper width, put sandpaper on it then sand down the opening to accomidate the propeller

eaglelope

I'm building the same CG Chipmunk as you ricknkim. I've run into a spinner issue also.

The local LHS doesn't stock aluminum spinners but that's what I want on the plane. I'm using a Magnum 91RFS 4 stroker.

I ordered a Great Planes 2 1/4" spinner (my plans say 2 1/4 go figure). I also ordered the OS adapter kit for that spinner (they don't have a kit for Magnums but it's supposed to tbe the same as OS). Everything threads on just fine but the problem is that when I install the backplate, the APC 14x6 prop, the prop washer, and the first nut, there isn't any room left for the locking nut. The locking nut is also the attachment point for the spinner.

Am I missing something or do I need start grinding stuff down so it all stacks properly?

Mark

ricknkim

Yeah I am having the same problem. The prop shaft on my YS 91 is too short for the prop, washer, nut and then spinner nut to attach the spinner. Not sure what I am going to do about this, I can get it to fit if I omit the prop washer but not sure how safe that is...

eaglelope

I looked at it some more and have two ideas:

1) On the GP Spinner, I could leave off the first nut. I don't think it's a good idea to leave the washer off as it spreads the load out over the prop hub. The problem is that the outer nut is smaller and doesn't contact as much of the prop washer so I don't know if that's safe either.

2) Use a different brand. I was looking at the Dave Brown Spinner here: [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXB946&P=7]spinner[/link]
The adapter for it looks like a single piece nut. [link=http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXB953&P=V]OS adapter[/link]
Here's the adapter for the YS [link=http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXB956&P=V]YS adapter[/link]
That combo might work since it eliminates one of the nuts. I might even be able to use the Dave Brown adapter with the GP spinner I already have. They both use a 10-32 bolt to hold the cone on.

I have to keep reminding myself that this is fun.

BTW, I did at least get the LE on my wing last night. I see what you mean about the spacing being tight. I just squeeked by but it fit with minimal sanding. On to flaps and ailerons!

Mark

voyager_663rd

same problem, different plane, different engine.

saito 100 with the ryan sta-m spinner that came with the bird and an apc prop. I'm left with just under 1/4" for the saito adapter to act as the locknut. Others have told me that its because of the very thick prop hub that creates lack of room to have more space at the locking end.

I've run it so far (virgin engine) without the spinner/adapter, just the backplate/prop/washer/nut/locking nut. no room for more than that.

It'll be interesting when I switch the locking nut for the adapter.

eaglelope

I'm still at a loss. I looked on the Dave Brown web site and they say you must use a locknut with their adapter on 4 stroke engines.

The crankshaft is only 1.25" (32mm). I don't how an aluminum spinner will fit unless I can find a prop with a thinner hub. The APC 14x6 is 1/2" thick. Surely someone has figured this out...

voyager_663rd

It's been suggested to me by another pilot to use a nut half the original size. Also, one has used just the adapter (in place of the locking nut)--prop/washer/primary nut/adapter.

He's had no problems doing this.

Paternguy

My Feedback: (1)

Do not run the engine with out the washer, the nut will burn its way through the prop and the engine will then trow it.

Take your original nut to a local machine shop or use a grinder if you have one, and machine it down to half its original thickness.

RDonovan

Harry Higley makes a line of "Light Locks" for short shaft engines. These are light weight, thin locking nuts. They come in various sizes to match the diameters and threads of many engines. Don't ever run a 4-cycle engine without a thrust washer or a locking nut.

Richard

Robotech

My Feedback: (9)

Try the folks at Tru-Turn. They can custom cut your spinner for any blades or shaft and it will be balanced. They also carry the spinner nuts. Very helpful people on the phone too.

delman

Like Robotech says - contact TRU-TURN in Houston with info on prop and engine - they work with you

voyager_663rd

One of the other folks is grinding down the flange of the adapter so it fits inside the nut (where the locking nut would normally fit itself into). Crappy weather here for last 10 days so I haven't had a chance to try this arrangement out yet.

eaglelope

Great tips guys. I'll give Tru-Turn a call!

Thanks much!
Mark

jparker

What is the best spinner to be used with APC props?

eaglelope

I don't know about "best" but TruTurn has spinners custom cut for whatever size APC prop you want. The spinners cost a little more but I think it's worth it to save the trouble of grinding and balancing. AS indicate earlier they are very helpful on the phone, just tell tehm what you are trying to do and they'll help you out.

I believe Dave Brown products will also custom cut spinners for you for a nominal fee.

Mark

2slow2matter

My Feedback: (1)

I've used a prop nut alone on my saito 100 for months now. Just the prop, washer, and prop nut--no other nut or locking nut. I put a screw driver to it every now and then to make sure it stays tight, but I've never had it loosen up one bit! I know this is contrary to the manual and other folks, but I've done it successfully. In fact, I'm fixing to put the same engine on a Texan, with a dave brown aluminum prop. What I plan on doing with it is using the washer, original nut, and then jamming the adapter up against the nut for locking purposes. I'll check on it every so often to make sure it isn't loosening up. I think one of the biggest keys is how tight you get the first nut on. Get yourself a regular wrench, and don't be afraid to get nasty with it--it has to be tight, especially on four strokes! Then, get that adapter nut tight--real tight, and you should be good to go. This is the setup my brother has right now on his aluminum spinner/saito 100 combo, and is what i'm planning on myself here in a couple of weeks!

FlyingPilgrim

My Feedback: (26)

I just caught sight of this thread, hope I caught some of you before you threw your props. Get the Tru-turn "short shaft" adapter kits for your 4-strokers that don't have enough thread. They are a double lock nut adapter (always use double lock nut w/ 4-stroke), but the nut is counter-bored to recess into the prop. Using them requires boring out the front half of your prop with a stepped drill, which is available from B&B Specialties (Bennett Built). Drills cost about 12 bucks.

When opening your spinner backplate to fit shafts that are too big, make sure to use a reamer. Best one I've seen yet is the Great Planes Precision reamer, not their standard one. Big difference in accuracy. Hope this helps.

Pilgrim

By the way, I believe the smallest spinner that will fit over these adapters is the 2 1/2" unless you go with an "Ultimate" type longer shape, in which case a 2 1/4" should fit over it.

jparker

All,

Thanks for the pointers. I will be looking into the Tru-Turn product.

FlyingPilgrim

My Feedback: (26)

You can't go wrong with their products. I have some of their spinners, and most of the adapter kits I use are Tru-Turn. They fit right, and have something to fit whatever you need. Spinners are a bit pricey, but the adapter kits are reasonable. It you don't see it on their web site, call them.

Pilgrim

MinnFlyer

My Feedback: (4)

Ok, I'd like to point out a few things.

First, I've never found a spinner yet that didn't require enlarging the holes for the prop. This is due to the fact that spinner manufacturers don't know what size prop you're going to use, so they make the holes to fit the smallest (feasible) prop. YOU must make the hole bigger - this is standard practice with any spinner (Which is one reason why a Dremel tool is almost a "MUST HAVE" item in this hobby)

Next, as far as the nut goes, It's far more important to use the washer than to use the lock nut. I have been using Dave Brown Spinner adapters on my 4-strokes (OS, YS and Saito) for many years with no problem.

Here's a link to the prop nut for a YS 91 (Or 110) :

http://www2.towerhobbies.com/cgi-bin...?&I=LXB956&P=0

If you don't know your thread size, check this chart:

http://www.greathobbies.com/document...rankchart.html

Once you find the size you need, go here and scroll down to Dave Brown:

http://www2.towerhobbies.com/cgi-bin/wti0093p?&C=QKC

FlyingPilgrim

My Feedback: (26)

You can get Tru-Turn spinners cut with 1.20 size slot in several sizes of spinner. Not custom order, but in stock, off the shelf. They fit the common 15x8 APC props nicely with no trimming. You can have them custom cut a spinner if they do not offer it off the shelf for most popular props (I do have one nylon GP spinner with aluminum back plate that I did have to cut the prop slots for, but most of my aluminums spinners did not need a thing).

I don't think the Dave Brown adapters have the double lock nuts. I'll take another look at their product line, though. I would not use a single nut adapter on a 4-stroke if there was a double lock nut type available, even it it did cost a few bucks more.

Pilgrim

MinnFlyer

My Feedback: (4)

Well, if I a locking type was available, I'd get it (If it weren't TOO much more) but my LHS has the single-nut type in stock, and I've never had a problem with them. In fact, I just bought another for my OS 70

eaglelope

FWIW, when I was looking at the Dave Brown adapters I saw some fine print on their web site that said four-stroke installations should use the prop nut that came with the engine and then the spinner adapter nut (making it the lock nut).

I bought one of the Higley light lock nuts and I think that would work fine in place of the washer and prop nut leaving ample room for the lock nut/adapter. The light lock nut is about the same diameter as a prop washer and the corners are beveled such that the "footprint" on the prop hub is a disc.

I have a TruTurn spinner on the way that is the Wide Blade version, it is supposed to be able to take an APC 14x6 without additional cutting but we'll see when it gets here...

Mark