Anybody else scratch building tonight?

Brian B

Elite member
The rear fuselage for the XPS Sea Hawk built in the same way as the fuselage centre section.
View attachment 204009
The more complex shape and the small radii make the planking a challenge in 5 mm XPS.
The completed rear fuselage glued onto the centre section.
View attachment 204010
Still the tail surfaces and the fuselage nose section to do.;)

Did you apply some sort if skim coat to fill before sanding? What is that grayish foam, never seen that before.
 

quorneng

Master member
Brian B
The foam is XPS 5 mm underlay. There are 19 boards 600 mm x 856 mm in each pack. You can make a lot of planes with that!
Light weight filler can be sanded carefully with fine sand paper. The foam itself needs coarser paper and the sanded surface needs filling with a smear of light weight filler to achieve the same smooth surface as the original foam.
 

The Hangar

Fly harder!
Mentor
Built these at ff:
6C9E7E76-A06D-4627-A99C-E1647C8ADE84.jpeg 3ABCD70B-AD11-4EC0-A908-A470BFED0C42.jpeg
 

Brian B

Elite member
Brian B
The foam is XPS 5 mm underlay. There are 19 boards 600 mm x 856 mm in each pack. You can make a lot of planes with that!
Light weight filler can be sanded carefully with fine sand paper. The foam itself needs coarser paper and the sanded surface needs filling with a smear of light weight filler to achieve the same smooth surface as the original foam.

Ah, Amazon UK! Alternatively to Depron I guess, but still can't get that or the other here in the US. Seems all underlayment here went to rolls. Stuck building with paper-lined foarmboard. I removed the paper for compound curve work, taped it afterward, but found hardness was too soft. Still looking for that "right" stuff.
 

chris398mx

Master member
Ah, Amazon UK! Alternatively to Depron I guess, but still can't get that or the other here in the US. Seems all underlayment here went to rolls. Stuck building with paper-lined foarmboard. I removed the paper for compound curve work, taped it afterward, but found hardness was too soft. Still looking for that "right" stuff.
I think there are 2 sources for Depron foam in the US right now. www.RCfoam.com and www.rcdepron.com
 

Indy durtdigger

Elite member
I think there are 2 sources for Depron foam in the US right now. www.RCfoam.com and www.rcdepron.com
That Rcfoam store is out of depron and has been forever, if you check their site all of it is on a waitlist. That other site I've not seen before but it does look like they have the stuff in sample packs.
Another source of depron is Home Depot and some other building supply stores, they sell it as floor underlayment and insulation. Two problems with it is that it's pricey (but significantly larger sheets) and since it's not hobby grade it can have some issues undesirable to our pursuits. Having said that NumaVig on you tube uses the box store stuff in all his vids so it must not be that bad.
 

The Hangar

Fly harder!
Mentor
They looked and flew amazing in person, it was nice to see you ar flitefest. Thanks again for helping me build my legacy
Yeah, they sure did! It was great getting to see you at Flitefest as well, I’m glad we got your legacy in the air! Did you have some more successful flights on it?
 

Ryan O.

Out of Foam Board!
This is my "cooldown build" before I start cutting out parts for another big project. My prediction is 110mph on 4s, 120 with an irresponsible prop.
image.jpg
image.jpg
image.jpg
image.jpg

Every LE and TE is tapered for minimum drag, including the little bit of foam which sicks out next to the firewall (even the hatch tape is shorter than normal) and I didn't do the scale paint job for orientation's sake.
 
Last edited:

Wildthing

Legendary member
Ah, Amazon UK! Alternatively to Depron I guess, but still can't get that or the other here in the US. Seems all underlayment here went to rolls. Stuck building with paper-lined foarmboard. I removed the paper for compound curve work, taped it afterward, but found hardness was too soft. Still looking for that "right" stuff.
Try MPF , Model Plane Foam
 

quorneng

Master member
Still ploughing on with the Sea Hawk. The tail feathers added.
TailOn3.JPG

These are not 5mm XPS but use some of my scarce 3mm Depron but built the same way as the wing with 2 skins over Depron shear webs. The elevator halves are joined with a piece of glass fibre tube. The elevator servo is in the fuselage right under the tail plane. All the servo wires have been extended forward into what will be the cockpit area. The RH wing has been given a coat of dark grey emulsion (US latex) paint.
Nose section next.