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-   -   Gas profile (http://www.rcuniverse.com/forum/profile-fun-flying-planes-105/11350028-gas-profile.html)

jp1961 12-30-2012 02:52 PM

Gas profile
1 Attachment(s)
My current winter project. A Yak profile with a Homelite 25cc for power. I'm thinking outside the box by using extruded polystyrene foam (1") for the fuselage core (5/32" plywood outer skins). All electronics (minus aileron servos) will be inside the fuselage. Wings are expanded styrofoam. Channels were routed in the foam for servo wiring. Fiberglass was added between the foam and plywood. I may have to add an additional layer on the outside of the plywood.

ahicks 12-30-2012 06:45 PM

RE: Gas profile

Just an observation though? After a few "less than graceful arrivals" over the last 2 flying seasons (which didn't seem to be all that bad at the time), I managed to break my fuse completely in half right behind the wing .... 3 different times (67" OMP Fusion). This would happen with no other damage anywhere. Got fairly predictable. If a wing tip catches first, doesn't seem to matter what speed that occurs at, the fuse will not survive it? By checking out a few build videos, I see thinking is to run tubing down through the center of the fuse for this exact reason. Tired of fixing that fuse, my somewhat tired (beat!) Fusion has been retired. I've had so much fun with it, and learned so much, a new Mojo 65 should be here any day now!

JWilliams 02-06-2013 10:43 AM

RE: Gas profile
JP1961, foam core fuselages sheeted with balsa is nothing new to profiles. Been done many times and it works well, to address ahicks concern of the fuse breaking behind the wing, well you can install CF tubes in the fuselage. Judging off your picture it may be too late for that at your stage of construction. Good luck on your project.
Jeff Williams

closetguy 02-06-2013 03:02 PM

RE: Gas profile
should be strong with the 5/32 ply you sheeted with,most are sheeted with 3/32 balsa.

Ernie Misner 02-10-2013 10:04 PM

RE: Gas profile
Cool! Did you take the basic design from any other plane? Did you convert the Homelite?

flygilmore 02-14-2013 09:32 AM

RE: Gas profile
Seems neat and I know that its fun to do engine conversions but that Homie is going to add a lot of weight for little power. The best Homelite was the 33cc out of the Ranger and Bandit saws. Still though, heavy by todays standards on all the small gassers. I bet an XYZ 20 or DLE 20 would give you a lot more power for more than half the weight.
Good luck!

keyman 02-24-2013 03:45 AM

RE: Gas profile
Any updates?

jp1961 03-08-2013 04:57 PM

RE: Gas profile
Yes, I converted the Homelite. I have a Bridgeport and lathe in my basement. I posted a new thread with a picture. I basically copied and enlarged a SIG Fazer profile.


karolh 03-19-2013 01:19 PM

RE: Gas profile
1 Attachment(s)
I just completed a scratch built gas profile using a similar method of fuse construction, except I used 1/2" wide x 3/8" hardwood spars for framing the fuse which was covered with 3/16" thk. lite ply door skin with numerous lightening holes. For rigidity I installed 2- 5/16" O.D. CF rods from midway the fuse right to the end. The 64" span wing panels are from a crashed Katana that were donated for my build project and for power I have a Mintor 22cc up front. My design was based on being a general sport flying model, no major 3D stuff and it's specs are:

Wingspan 64"
Length 59"
Wing area 810 sq."
Weight 8.5 lbs


ahicks 03-20-2013 03:33 AM

RE: Gas profile
Nice job Karolh! Hope it flies as nice as it looks. Choice of materials interesting, but at 8.5lbs, it sounds like they really worked out well!

karolh 03-20-2013 06:54 AM

RE: Gas profile
1 Attachment(s)
I was really shooting for an AUW of 8.0 lbs. and in retrospect if I ever decide to build another I would use hard balsa spars for the framing and run the CF rod from nose to tail which I think would put me right in the weight range I was hoping for.

acerc 03-20-2013 01:24 PM

RE: Gas profile
If your worried about being too heavythis is my profile, a Swanyhouse primo 65"ws and it weighs 7lbs on the money and is a floater. So I think you will beok at 8lbs.

karolh 03-20-2013 07:29 PM

RE: Gas profile
I am not overly concerned about the weight but lighter most times flies better. How about sharing a picture of your profile.

acerc 03-21-2013 04:22 AM

RE: Gas profile

Pics? Gladly.</p>

karolh 03-21-2013 08:34 AM

RE: Gas profile
Thanks for sharing, now that's a really nice looking model and I just love the covering pattern and no need to ask your nationality;) That sure is a whole lot of wing no wonder it floats, how much sq. ins. is it.

CanCanCase 03-21-2013 01:54 PM

RE: Gas profile
Primo 65? When did that come and go unobtanium? The largest Primo I see on Paul's site is a Primo60, which has a 55" wingspan. Even at that, your Primo wing has close to double the area of karolh's Katana wings. Even at 7 lbs, that much area will certainly float. I've put a Saito 20cc 4-stroke gasser on a Mojo60 before... it's got the big wing like the Primo, and could handle the extra weight of that motor. I don't think an 8 lb+ bird with nearly double the wing loading would like that heavy of an engine, but maybe that's just my flying style too...

I think when I'm ready to play with 20cc gas again, it will be on an EE60, Ron Williams Sbach65, Mojo65, or the big Slide coming out.




If your worried about being too heavy this is my profile, a Swanyhouse primo 65''ws and it weighs 7lbs on the money and is a floater. So I think you will be ok at 8lbs.

acerc 03-21-2013 03:40 PM

RE: Gas profile
My apologies on the wingspan, it is 55". And the wing area is 1000sq. in.

karolh 03-22-2013 09:38 AM

RE: Gas profile

[quote]ORIGINAL: CanCanCase

I don't think an 8 lb+ bird with nearly double the wing loading would like that heavy of an engine, but maybe that's just my flying style too...


My model was designed primarily as a sport model and with a wing loading of 24.2 ozs. /sq.ft is in the range of most sport types having excellent flying manners.

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