Brad330l

My Feedback: (1)

Hi composite gurus. I am after any advice you might want to give while I make my Yellow Aircraft Spitfire static spinner into a flyable one.
I am hell bent on doing this as I reckon my aluminium one has the wobbles, looks horrible and is heavier than required. I only have five flights on my pride and joy and it is because of the spinner vibrating and shaking things loose to the point of failure. I have lightened the back plate (I will be setting this up in a lathe and checking the runout and fixing this) and balanced the whole lot and checked it a couple of times BUT it still has runout like the outside and the bore for the crank shaft is not concentric. Like I said I can fix or remake the back plate,,, that is not a problem,,, what I need from you is to have a look at what I want to do with the cone and suggest any tips.

As per the attached pictures I would like to use carbon fiber ribbon and laminate it to the inside of the cone in four places from the front to the back where the back plate goes. I would cut these pieces a bit short and finish them off with another length of ribbon that would go right around the internal circumference of the cone where it would bolt to the back plate. This would make the rear of the cone a bit thicker and stronger so when in the lathe I would need to machine the back plate down to the correct diameter and so making it 'true' and allowing the cone to fit nice and snug.
Alternately instead of the ribbon I have some carbon 'cloth' that I could coat the whole inside of the cone with by cutting triangle sections and laying them in. Once again machining the back plate to suit.

The spinner is made with polyester resin and I would want to use my West Systems resin to stick it all together. If you think otherwise please let me know.
I am thinking that the static spinner is nice and concentric and I will be able to confirm this by spinning it up on the lathe after I deal with the back plate. If it is not I will be able to sand it until it is, having the extra strength inside. Then balance and then fly with a nice looking, light, strong spinner.

Cheers,

Brad

SCALECRAFT

My Feedback: (13)

Hi

Nice to see someone do this. We have been making and flying our own composite spinners for years now. Some have been spun up to around 20,000 rpm.

We make our spinners out of MDF (medium density fiberboard), turned on a lathe. Some have a step down lip to set the spinner in the Back plate groove, like a plastic one. Some just set in the back plate groove as an aluminum one. All true out of the precision molds. Just a bit of balancing needed.

One thing you may consider for support of the spinner along with carbon is a small wood or composite disc inside the section of the spinner beyond the prop hardware/shaft. Look for a pic of a real BF 109 spinner that has a view of the back. The 2 piece 109 spinner has such a disc.

I will try to find the pics of some of our composite spinners.

Use good epoxy resin such as west system or US composites.

The black one, BF 109G spinner with support lip for back plate, gray one Fiberclassics P-51D spinner, plug of Zero spinner out of MDF, BF 109 Composite spinner off an alum original.

Good luck

Steve

Brad330l

My Feedback: (1)

Hi Steve, thanks for your info and let me say you have the spinner making down pretty well. They look very nice. I wish I had a decent little lathe at home to be able to do my work. I have to ask the boss to be able to use the one at work and I can only get it for a short time. (get back to work you!!!!!)[:'(]

So not too bad an idea you reckon to try this?? If you were going to do it with what I have available which way would you go? The four ribbon strips or the cloth? I am leaning toward the cloth.

Cheers,

Brad

SCALECRAFT

My Feedback: (13)

Cloth cut in triangles overlapping as evenly as possible.

Steve

darren763

My Feedback: (117)

Why not cut the glass in a circle with a slit in it? Would that work better?

Thanks,

Darren

wyowindworks

The problem with a circle is that the spinner shape isn't really a circle. Either there is too much fabric at the wide edge or not enough fabric in the middle portion. It's also very problematic trying to get a single peice of fabric into the nose cone mold and keep and fiber correctly oriented. Ideally, you want fibers that are parallel with the length and width, and then have fibers that are +/-45 to the lenght and width. This will yeild the stongest, most durable, and most stable layup. To use a circle cut, the fabric would have to be woven in circle to properly align the fibers. Secondly, getting the fabric into the tip is quite difficut with a split circular cut. The atvantage to the " bulged" triangle is the fabric can easily be worked into the tip. The overlapping fabric at the tip will strenghthen it on impact. Also the correct fiber orientaion can be maintained...which is imposible with circle cuts. Lastly, the balance of spinner is more easily acheive with triangle cuts. With a single circle cut the seam fails out only on one side (unless 4 layers are inserted and staggered 90*). With triangle cut the seams can evenly distributed around the entire diameter of the cone.

SCALECRAFT

My Feedback: (13)

All of what wyo said.



Steve

Brad330l

My Feedback: (1)

I have finally had a look at my spinner and cut out some template shapes so I get the carbon pieces just right for the conversion.
As you can see the first attempt was close but ,,, no cigar. A bit of an angle adjustment should see things right. My thinking is that the carbon cloth does not need to go right to the nose of the spinner. What do you reckon? How much overlap of each join do I need?? I am thinking maybe 6mm (1/4")

Back soon, cheers,

Brad

Brad330l

My Feedback: (1)

After adjusting the shape of the template I cut out the five pieces of carbon cloth and got everything ready. I set my self up so it was going to be a nice easy operation and not a disaster. I mixed up some West Systems and off I went, firstly just wetting the inside surface of where I wanted the initial piece of cloth and then wetting it in (again just). I worked around until all done and then blotted off as much resin as possible. With the prop holes now covered it sould be easy to fill them in with some cloth and filler ect.
It is drying at the moment so i'll check back in after I trim and fit the cone to the back plate.

Cheers,

Brad

Brad330l

My Feedback: (1)

After trimming the spinner of excess carbon cloth I test fitted the cone to the back plate and with a big surprise it fitted perfectly!!!!!!!!!![X(]
So with the obligatory piece of tape in place onto the Spitfire it went for a look.
Looks good. Next is to fill the circles for the static prop blades with micro balloons and West's.

Cheers,

Brad

wyowindworks

Nice work!

kenh3497

Something must have went terribly wrong........... It looks perfect!


Nice job. Now that you have experience, you can build a spinner for my Zlin!

SCALECRAFT

My Feedback: (13)

It's impressive when modelers make their own composite parts like this. This stuff raises the bar and wins my respect.

Nice

steve

Brad330l

My Feedback: (1)

Thank you guys, I feel spoilt by you.

Yes, all OK so far but the proof will be when finished and spinning at 9000RPM.
I have been a bit lazy the last week but will continue soon. Must finish to fly Spitfire.

Cheers and thanks again,

Brad

Brad330l

My Feedback: (1)

OK, got some 'Hen pecks' (Honey Do's) out the way, and it is Christmas, so got into the shed and got to fill in the holes for the static prop blades on the spinner.
Using West Systems I mixed in some fibre glass powder and lighter stuff to make a nice paste to fill in the holes. I then scraped off the excess with a credit card (got to use them for something right??) to the profile. With a little bit of 'paste' added to the inside it was time to watch it dry Next will be sanding and filling and then onto mounting onto the back plate. Hey,,,, I might be slow but by Jez i'm rough!
Cheers,

Brad

SCALECRAFT

My Feedback: (13)

Looks really good. Back before brushless motors, I mounted mine to a router and spun it up to see what I got.


Steve

Brad330l

My Feedback: (1)

Hi again guys, I havn't quite dropped off the planet, and I have actually achieved something with the spinner.
As of tonight it is mounted on the Spitfire with prop and all. I used a little lathe I was given to adjust the base to correct some run-out and got it to .12mm, not bad just over ten thou.
Painting and balancing is next and then I'll show you a picture.
The thing I'm sure you are all interested in is the testing and hopefully operation of the spinner and this I promise to report on good or bad.

Cheers,

Brad

Brad330l

My Feedback: (1)

Hi guys, I am finally able to report that my spinner is actually flyable.
I took my Spitfire to a warbird meet and got three great flights in with no problems at all.
I made sure I dialled the nose cone up to within point two of a millimetre of runout and used tiny washers (although steel ones, I will get some nylon ones) to ensure things held together.
It looked great and to get the model home I had to remove the prop so off came the spinner (screws were a little looser) and after a quick inspection there was no faults found.
Awesome. Cheers for your help.

Brad

SCALECRAFT

My Feedback: (13)

Now, doesn't that feel great. A composite spinner you made yourself.

Now, the composite props.

Just remember to keep everybody and yourself clear of high speed moving parts.

No matter who makes them.

Good work.

Steve