SU25 Frogfoot

[billscottni]

A wee bit more done this weekend.

The two engine pods are framed up and just need sheeted. Started to mark out foam for the wings only to discover all the bits I have are about an inch short!!
Wings may have to wait until January.  :cry:  :!:
Over the next couple of days, I hope to get the tail cut, ie two all flying elevators and the vertical fin.

After that I may move across to the Jart until I get the foam for the wings  :?:

[billscottni]

Quite on this build for a while, so I did a little today.

After looking in a lot of websites for a bellcrank of the right size.. I gave up and bought some pcb from Maplins and fabricated my own.

Sorry about the pic. My camera's playing up, so this is taken with my phone



Going to do some more work on the engine pods tonight and possibly cut the wing tomorrow. Will start with the tails and see how it goes.

[billscottni]

Got the sheeting done top and bottom of the fuz today after installing the control horn:



Noew ned to start shaping the fuz edges to get a "slightly" more rounded shape. First of the top decking has been shaped in blue foam and is currently sitting on top of the radiator with sheeting drying. This piece will run from the back of the cockpit to the LE of the wing..


All in all a productive weekend, (for a change!) :clap:  :?:  :?:

[joe]

Good stuff Bill. Sure you're flying along now!!

[billscottni]

Got a bit more done tonight: Tails are cut. I used a single point taper cut to do these as they are small and quite highly tapered. One end of the wire is stationary and the other end swings through an arc, cutting the foil as it goes. Very pleased with the results.



This is the cutter. The far end is on a pivot (Screw in this case)





Planform of the tails




The airfoil section is SD8020, fully symetrical. Will have a balsa skin adde and a balsa LE

[JohnPearson]

Hi Bill

Looks good, you will have to show me the cutter in action when I am down your way next. I would like to try this method myself for small wing cutting.

[billscottni]

No problem John. check your e-mail, I have a website coding quesstion for you!!! :?:

[billscottni]

Haven't managed much this week. The job as sceretary of NIAA has taken up a fair bit of time in the last fortnight :!:


Ordered a pilot for the model, (can't have an empty cockpit!!) Bought from Pete's Pilots on Ebay

http://stores.shop.ebay.co.uk/Petes-Pilots__W0QQ_armrsZ1



Need to give him a paint job when I find a decent pic of a Russian pilot

[billscottni]

Well, lack of wind and forecast snow showers meant no flying today :cry:
Instead I got my a**e in gear and cut the foam wings and fin for the Frogfoot. I'm currently using a drop arm cutter for wings and as the fin is highly tapered, I use a single point cutter for that.

Using a drop arm cutter, you have an arm fixed at one end and by attaching the pull cords for the bow at different points, it pulls the ends of the bow through the foam at different speeds.



All set up and ready to go



Bottom template for the narrow chord at the tip

I'm waiting on a Hobby CNC kit coming from the US to complte my CNC cutter, which will make these cutters obsolete. They are useful for one off cuts and will satisfy the neds of most modellers

[billscottni]

The obligatory "Bench Fly" pic!!



Lot of sanding and shaping to do before paint :wink:


And a couple of vids I took while doing the cutting. Quality isn't great, but it does show how the two types work :?:

[youtube]http://www.youtube.com/v/oVvE9CUALcQ[/youtube]


[youtube]http://www.youtube.com/v/kb3Bz7IThkw[/youtube]

[JohnPearson]

Hi Bill

Looks good, you we have to show me how that system works, the wings look perfect, good job!!

[billscottni]

No problem John. It's definitely not rocket science and mine is a very Heath Robinson set up :wink:

I have  small computer program that calculates the attachment points depending on the taper of the wing and its chord. After that you set it up, put the bow in place, turn on the heat and leave it alone until it's finished the cut    

[billscottni]

Bit more work done in the last week. Wings are now sheeted, little bit of glass and CF tow at the trailing edge to allow me to sand to a thin TE



 I also finished the sheting on the fin and tails. Tails have a surface finish of tissue and polyurethane varnish, which will hopefully take paint well :?:


John appeared the other night with a little pressie for moi. A tucano that had been built for a small power plant in the nose. That's now removed and the nose is being faired in



Needs a bit of a refurb, but I should have both models ready for the PSS event

After all this work, the shop is not as tidy as it could be!!!

[Fred]

Looking good Bill !  :clap:  :clap:
Like the Tucano too !!

Fred - Just realised that he seriously need to remove the fingers and start to do a PSS !!

[billscottni]

You'd better Fred, by my count 17 days to go