Shell Wing

[Motorman]

I thought I read a while back that someone was making wings by molding carbon fiber shells and gluing them together? Anyone know the details about this?


MM

[Tim Wescott]

Jose Modesto has done that.  Something should pop up in a search, if you want to test your Google-fu.

[Chris Wilson]

Yatsenko models do similar.

[Brett Buck]

I thought I read a while back that someone was making wings by molding carbon fiber shells and gluing them together? Anyone know the details about this?


MM

 I think Kaz is coming the closest to doing that. Jose and the Yatsenkos still have balsa in them, if I under correctly.

    Brett

[BillLee]

Many (most?) new F2C wings are now molded in a CNC aluminum mold. Top half, bottom half. Foam or balsa filled and then glued together.

[Chris Wilson]

The Yatsenko wing that I saw under repair only used about 3 wide foam ribs to stop drumming noises and those were an engineering cosmetic.

The shells I think were glass not carbon though.

[Tim Wescott]

AFAIK the lightest and strongest composite wing construction would be a shell with a CF or CF/kevlar layer, then about 3mm of foam, then another fiber layer.  Occasional ribs or a "spar" to hold the skins apart at the high point might be a good idea.

Light balsa might actually be a good alternative to thin foam, as it might have better noise reduction qualities -- but given that I've never laid up CF, I'm so far out on a limb here that I may as well be floating in air.

[Brett Buck]

AFAIK the lightest and strongest composite wing construction would be a shell with a CF or CF/kevlar layer, then about 3mm of foam, then another fiber layer.  Occasional ribs or a "spar" to hold the skins apart at the high point might be a good idea.

   1/4 paper or aluminum honeycomb is pretty light, too.

    Brett

[Dennis Toth]

Windy did this on Miss Ashley there might be some videos on U Tube. Dave Migley (sp?) also did some wings like this.

Best,       DennisT

[Geoff Goodworth]

Dee Rice published an article in Flying Models several years ago showing how he did the same using a foam core to provide the initial shape.

Without checking, I think it was the issue with the Pathfinder LE in it.

[PJ Rowland]

Full carbon wings aren't as light as balsa.

[Dennis Toth]

In building a shell wing the main thing to control is the amount of resin. The fiberglass or carbon fiber material is not where the weight comes from. You need to squeegee off as much resin as possible. This is similar to the toilet paper/glass method used for covering flaps where you first wet out the fiberglass, lay it on the part then using a playing card or old credit card squeegee off the resin then roll it with toilet paper to get the last of the excess off. Some guys give it a second coat and repeat the process. This give a very strong and light part.

For the wing shell if you have a foam core you could cover the core with wax paper then lay the wetted glass on it and do the squeegee thing, make two half's.  Build a strong spar and use some resin filled fiberglass twine (stuff they use at Home Depot to hold things to the roof) as a bead along the inside leading and trailing edge as you put the two half's together over the spar. This is how Wind Turbine blades are built.

Best,         DennisT

[jose modesto]

Late to the party.was on Holliday.
attached some photos showing various ways that i use the shell construction.
The shells can be used to build ribless wings,open bay wings,covered foam and solid builtup wings.
photo 1 SV 22 wing kit NOT FOR SALE
#2 SV 22 shell wing
#3 wing tip
#4 using shells to cover foam wing
#5 Bob Hunts custom foam inserts for SV22
#5 foam insert premolded balsa painted mold
#6 inside of molded ribless,sparless wing panel

[jose modesto]

added photos

[jose modesto]

added photos
Photo 7 painted in mold wing panel

[jose modesto]

added photos
last photois molded Impact fuse with electric mount  fuse 5.2oz   

[frank williams]

Jose
As always very nice work ... what is the weight of just a single skin (mine are still coming out a little too heavy) .... I assume its glass/balsa/glass?
Frank

[jose modesto]

Hey Frank,hope all is well.
The Saturn wing panels in solid balsa 1.3 to 1.5oz each panel. If you cut panel for open bay wings and build in a custom lost foam wing jig,the panels weights can be reduced to under one oz each.
SV22,Impacts and pattern masters are a little heavier as they are thicker airfoils
The painted in the mold can increase by .5 oz per panel for the Saturn wing.
I built a model with a Saturn wing at 8.5 oz the impact fuse was 5oz the molded stab at 1.3 oz and I hated that model to light,no penetration. Lighter not always better. Model would not land in the wind 52oz 650 SI

Since I build my wings in a lost foam wing jig,I use all the ribs shown but are not required for strength.
The Saturn and SV wings in solid balsa can be built under 10 oz with belcrank  and flaps.


The finishing process is greatly advanced do to the glass and epoxy outer surfaces. The painted in mold wings require little finish to complete.
One thing I learned is that the premolded balsa wings panels must have final sanding to get that perfect painted I finish.

[frank williams]

Thanks Jose, for the info.
For those have never tried this ...... there is a really big learning curve involved here ..... very nice work, Jose
Frank