RodneyFord

Sprayed the last undercoat on, a good thick layer along with the indicator coat. Am at the point of diminishing returns so it is on to top coats after this has been sanded.

AmericanSpectre505

Enjoying the post. Learning how to do this in the future, great blog.

Bill Holsten

RodneyFord

Thanks Bill. Keep in mind that this is just one way of making the mold pattern. The last 3 I have done were built up wood and I wanted to do a bit more hands on shaping with this one. I have also wanted to do a CNC pattern but don't really have the room for the machine.

RodneyFord

Waiting for fine weather to spray the top coat on the fuselage (winter here). In the mean time have been working on the Cromwell S800 31/2" precision lathe I have been restoring. This is nearly finished so I will be able to use it for the gearbox. Working on detail design of the gearbox. 8mm ground titanium bar arrived, this is Ti 6AL 4V or grade 5 which is a high strength alloy. I'm going to use this for the main shaft. Hopefully it is not too hard to thread and drill. The offcuts should make nice axles.

Edvkl

I´m about to do the same thing, building av F3A (2*2) meter. I have bulid quit a few over the years but newer disigned one. You have disigned the roderangel oposit from what I´m used to. Of course you have a good reson for that? Your fusulagedisign is quit strate forward apart from that roderangel. Looking forward to falow your progress

Edvard

RodneyFord

Hi Edvard i am not sure what you mean by roderangel. Could you please post a drawing of what you are used to.

Edvkl

Hi, what I mean is the vertikal angel between the fuselage and the roder.
I´m not very god with padgemaker.

Edvard

RodneyFord

Hi Edvard I understand now. I make the rudder hinge line vertical or perpendicular to the fuselage datum to try and keep the force of the deflected rudder in line with the datum. Also I have more area at the base of the rudder to balance the area above and below the datum. Hope that is a clear explanation.

RodneyFord

Decided to stay with epoxy undercoat for the finish coat as I know that it will release from the finished mold properly. Changed to white though and put a really light indicator coat on. 600 grit this time. Will start setting up for molding now. Am going to stay with an epoxy mold.

Edvkl

I want my disign to be ass neutral as posseble. When I use the roder i want the modell to move sidevays without the modell changing in any other way. On my Sebart Wind S i have to use mixers in both roll and elevator to kompensate when rodder is applayed. To disign a new model, as you do, and I´m about to do is difficult. To get it perfekt on version One is probbobly imposseble. Now i understand how you think. I will follow your thread with intrest.

Edvard

RodneyFord

Hi Edvard I don't know if you understand the causes of roll and pitch coupling to rudder (and also the effect of CG). It is reasonably well understood. A new thread on the subject might be a good idea though.

Tried sanding the plug but the paint is still too soft for the 600 grit to work. Started looking at the splitter plate, this is the off cut from the keel used to make the plug. Painted some sealer on it and will start building the frame.

RodneyFord

The extra day of paint hardening stopped the clogging in the 600 grit. Once the sandpaper had got reasonably worn out it was perfect for the nose detail sanding.

RodneyFord

Finished off the sanding and cut it. The epoxy undercoat took a nice polish.

RodneyFord

After polishing the plug it bought to light a low spot. Not huge but once I knew it was there my eye kept being drawn to it. Had to be fixed, so will to do a full re-coat.

drac1

My Feedback: (4)

That's it Rodney. Once you know it's there, it will annoy you forever if you don't fix it.

RodneyFord

More paint on, hopefully the last. Need to wait a couple of days for it to harden.




Bearings arrived for gear box, am working on detail drawings for it.

RodneyFord

That's it, finished the sanding and I am happy with the fuselage. The extra coat gave the extra little bit of fairing too.

RodneyFord

Here is the release system I use. Fast and easy to apply and I know it will work. However it is so good that you cannot paint in the mold apart from a build up of very light coats of undercoat to act as a gel coat.

RodneyFord

I've got the parting plate framed up. Will start fine tuning it.

RodneyFord

Finally got the fuselage off the painting stand and offered it up to the parting plate. Some work to do around the nose where I have reduced the length for the longer contra spinner.

RodneyFord

Working on the parting plates still. You can see how much I shortened the nose for the contra spinner.

grahamj4

Iooking good, are you making the spinner as well?

RodneyFord

Hi Graham
The 95mm spinner size I have opted for means I will need to produce my own spinners. I have a system for making my own normal 2 blade carbon spinners which would work for the front spinner but the rear spinner needs a different design. I thought I would make them with my 3D printer. I have some nylon filament I am hoping to use if I can get it to print nicely. However PLA should be strong enough to do the job and will be fine for prototypes. If I need to make carbon spinners the printed ones will serve as patterns for the molds.

RodneyFord

Got the parting plate dams on. I will leave these attached to the mold halves to give the mold soft edges. Just need to decide on the registration method I will use.

RodneyFord

Sealing the parting plate to the plug with modelling clay. I have made various tools for this job.