5_spot

My Feedback: (1)

Or nose cone,on my plane i have the 2 1/2" for the three bladed prop,i got another one for a two bladed prop,same size,question is,could i drop down to another size for better air flow,say 2 1/4" or maybe just the 2" .
Thanks

a65l

My Feedback: (17)

Sure, you can go smaller. Just watch that the openings for the prop blades in the spinner cone DO NOT contact the prop blades... bad juju there. If you're really wanting to just drop the spinner but continue using a starter, Du-Bro makes a cone shaped hub nut that works perfectly with starters.

Andy

5_spot

My Feedback: (1)

I remember now,i was told if i went to a smaller one i would have to ream or grind it out for the blades,then i might have a balance problem,guess i'll keep the one i got.I was wondering about airflow to the prop if it would make any difference.
Thanks

Kaoma

My Feedback: (4)

Why should NOT the spinner touch the prop? On my both planes the spinner touches the prop quite tight with no problems.

zetor

My Feedback: (2)

What I don't understand is why doesn't someone step up and make a simple spinner that doesn't need grinding out for the wider props. I know I've read a lot of posts here where people were wanting to know how they should, or if they could, cut the spinner so the prop would fit. All you hear on here and at my club is how great apc props are but you can't find a simple spinner to fit the d**n thing. You have to spend 45.00 at tru-turn or get one by great planes only to find there isn't an adapter for it (not for saito anyway). I KNOW people would buy one if they were made.

a65l

My Feedback: (17)

If the spinner touches the prop blades, there's a chance that it could cut into them and weaken the prop.

Andy

flying_frog

I agree Zetor. I'm building a Glogal Decathlon with an OS 72 FX engine. Went through at least 5 or 6 different spinner/prop combinations to finally get a match. I wanted to use an aluminum spinner, but couldn't get a prop to fit. Wound up with a 2" plastic spinner and an 11x9 Master Airscrew prop.

I also heard never to use a plastic spinner on a 4-stroke. Is this a good idea or is it someone's opinion.

MinnFlyer

My Feedback: (4)

Simple... If they made a spinner to fit each brand (and size) of prop, they would have to make about 100 molds for each spinner. and of that hundred or so types, how many do you think your LHS would carry? And in what Color?

The simplest way around this is to make each spinner for the smallest (reasonable) size prop.

If you need it bigger, you can enlarge it, but if it's too big, you can't make it smaller.

Montague

I've run plastic spinners on 4-strokes for years with no problems. In fact, if you over lean it, and the engine kicks back, the whole prop+nut+washer+spinner comes flying off as a unit, making it easier to find, but more of a hassle to put back on .

The reason I heard to not have the spinner touching is that the blades to flex a little in the air. If the prop is touching the spinner, it's slowly rubbing, and that means cutting in to the prop. With a soft plastic spinner and a harder prop like an APC, I don't know if it would matter as much, but it's still a good idea to have some clearance. Also, if it's touching, it's possible you are warping the spinner as you tighten it down, which will cause a vibration when it's running.

As for spinner size, the inner few inches of the prop really don't do much anyway, so don't sweat covering them up. If anything, a larger spinner will often make a plane go faster as it smooths out more of the airflow around the fuse. I'm using a 2.5" spinner on a 9" prop, and the plane runs like a scalded cat.

DBCherry

My Feedback: (4)

As Kirk (Montague) just mentioned, buying a smaller spinner will very likely restrict airflow, not improve it.

You size a spinner so that the backplate is close in size to the front of the cowl so airflows around the cowl more easily. How much prop is covered by the spinner makes little or no difference. Most of the work is done by the outer portions of the prop, not the inner.
Dennis-

5_spot

My Feedback: (1)

I'm glad you pointed it out and i can see now that smaller isn't always better,getting air around the cowl sure makes it simple.
Thanks

5_spot

My Feedback: (1)

Here is a pic of my backplate and prop,as you can see,the prop rests against a stub on each side of the hub so i don't know if it makes any difference or not,putting the cone on it fits snug.Sorry for the pink pen.

DBCherry

My Feedback: (4)

Those "pegs" are there for the prop to rest against. They will supposedly allow the spinner to then fit over the prop 'prop'erly. It seems 75% of the time, they still don't fit right for me, but....

What a65l was referring to was the "spinner" (at the notches) touching the prop baldes, not the backplate). You should sand or carve a bit of the spinner 'slots' if they touch the prop.
Dennis-

5_spot

My Feedback: (1)

How do i balance the cone if i sand or carve or is it neccessary,and if so,how do i balance it ?.I'm thinking of giving it more room (on both sides)as one side of the prop is touching the cone.
Thanks

zetor

My Feedback: (2)

I have a great planes aluminum 2.5" spinner that will accomodate any prop for a .46 engine. It just looks to me like that there would be plastic spinners out there that could do the same thing. Is there a drawback to having a spinner that doesn't hug the prop? All the engine manuals that I've seen say it is so important to balance a prop. Well if it is so important, then grinding on a spinner and ending up with a balanced spinner looks like it would be very difficult.

Montague

As far as balancing spinners, yes you can do it on a good quality balancer. I've never bothered though.

Remember, the effect of being out of balance is going to be a weight * distance thing. So being a little bit off on a long prop is much worse than being more out of balance on something close in, like most spinners.

that's not to say that you shouldn't balance the spinner, just that many of us don't, and usually the world doesn't end as a result. If you do a pretty good job of getting the cutouts the same size, you stand a good chance of being close enough.

PipeMajor

My Feedback: (1)

Sig Manufacturing touts it's line of spinners (made by DuBro) will fit APC props with no modifications. The 2" spinner which came with my LT-40 kit accomodates an APC 11-5 on my Thunder Tiger 46 Pro nicely.

jak_kkaall

Can we safely use a plastic spinner on a 50cc two stroke engine?

speedracerntrixie

My Feedback: (29)

I have never considered it and have always used either aluminum, fiberglass or CF. That being said, I really see no reason why you couldn't use the Great Planes plastic spinners with the aluminum back plate. Once you get to a certain size they go from 2 screws holding the cone on to 4 screws so the size you would need would have 4. I have used fiberglass spinners that have 6 screws holding the cone to the backplate on 150cc engines

jester_s1

If you're using an electric starter to start the engine, I don't think one would hold up. If you're flip starting (as most do) I don't see how it would be any different than using one on a glow engine.

speedracerntrixie

My Feedback: (29)

Using a starter on a gasser is just wrong.

TomCrump

And why is that ?

Rodney

I find that a starter on magneto type gassers can be very helpful, I do it all the time. No problems. I never find it necessary on electronic ignition types.

JohnBuckner

My Feedback: (1)

The silly notion that a starter is just wrong on a gasser or that most do not use one is in fact wrong. The fact of the matter is starters can be a huge asset for any engine that needs it. Its that simple and I find that what Rodney posted above to be quiite accurate.

I have watched ever since the fellows sarted showing up with gassers and fight their gassors that were magneto types and missing many flying days for this reason I swore when I first started flying gasser which was only about five years ago (yes I waited a long time and was just fine with glow, still am actually) That I would acquire a "Capable big Starter" And am delighted that it works so well with anything. Nope I seldom need it with my two OS gassers but have needed it with some other older engines that I never would have had success without the starter which included the G-62 in my T-6, a Kalt rather vintage engine and a Turnigy 52cc engine.

Even though I am in a wheelchair I have had success with hand starting the OS' but not the magneto engines or the turnigy. So I absolutely carry my big starter when flying my gassers as well many of the others here at my home field. Big starters are hard to come by and can be expensive but so is the equipment you are operating, The proper support equipment is appropriate and never wrong.



John

izzy-israel-73

I tried a plastic spinner on my four stroke some how it kept coming loose!!! Not sure what the go was but I didn't like the noise it made when it let go!!!