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scratch building without balsa - 7/12/2003 9:46:38 AM   
zhanx


 

Posts: 12
Joined: 7/11/2003
From: stuck in kuwait right now
Status: offline 		heres are question i couldn't find (maybe i need to learn to search better) hmm. is it only possible to build and fly with balsa wood? cause due to my current location, i am unable to get balsa wood (due to the fact everything get crushed in the mail). due to the fact that we went to umm.. well war i got stuck here for a while so i decided to build an airplane. only i used 1/4" strips of dry pine (when its a 150 out everything is dry) so far the whole thing is light, not as light as balsa wood but light? will i need to go from a .40 to a large engine for it?

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scratch building without balsa - 7/12/2003 10:41:13 AM   
mikenlapaz



Posts: 1947
Joined: 12/6/2002
From: La Paz BCS, MEXICO
Status: offline 		Need more info before a reasonable answer can be given.
Maybe if you had some actual weights, wing surface area, and plane design someone could give you some realistic answers.

do they use wooden ventian blinds over there. The type with slats 2" wide and about 1/8" thick? Most are made from basswood which may be a better substitute for balsa, about 3x heavier but fine grained and good spinter resistance, weight similar to spruce.
wow 150 and I thought it was hot here with 105 in the shade!

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control - 7/12/2003 12:07:45 PM   
zhanx


 

Posts: 12
Joined: 7/11/2003
From: stuck in kuwait right now
Status: offline 		[QUOTE]Originally posted by mikenlapaz
Need more info before a reasonable answer can be given.
Maybe if you had some actual weights, wing surface area, and plane design someone could give you some realistic answers.

do they use wooden ventian blinds over there. The type with slats 2" wide and about 1/8" thick? Most are made from basswood which may be a better substitute for balsa, about 3x heavier but fine grained and good spinter resistance, weight similar to spruce.
wow 150 and I thought it was hot here with 105 in the shade! [/QUOTE]

umm so far i am 90% complete and the body and wings weight less than 2 pounds. dont have a scale to get much closer. the wing area is like 432sqin here is a photo of what i got(i have changed the trailing edge of the wing but dont have a picture). if anything it can hang in the den and look cool. As for substituting for pine.. not allow to travel to the area where you can get that kind of stuff.. almost everything was bought mail-order except the radio and servos.

btw on the 150.. the temp gage only reads 140 and i have seen it peaked out pass that a few times.. its a cool day today at only 124 right now

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scratch building without balsa - 7/13/2003 5:19:16 AM   
Woodsy



Posts: 1719
Joined: 9/24/2002
From: DrouinVictoria, AUSTRALIA
Status: offline 		Well no balsa is by far the only option available.

have a look on the SPAD forum here on RCU or [url]www.spadtothebone.com[/url] or you can use EPS or EPP foam or theres fan fold foam and good old card bord, i've seen a nice twin built from corugated card (similar to SPAD technology)


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scratch building without balsa - 7/13/2003 8:34:11 AM   
susquach


 

Posts: 294
Joined: 1/15/2003
From: kerrville, TX, USA
Status: offline 		zhanx,
you might be interested in a biplane design done years ago by John Northrop named the spruce goose. Like your effort, he developed a structure almost entirely of hardwood. Believe it appeared in either MODEL BUILDER.

ddubya

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scratch building without balsa - 7/13/2003 11:48:51 AM   
BMatthews



Posts: 8951
Joined: 10/4/2002
From: Burnaby, BC, CANADA
Status: offline 		Yer doin' fine near as I can tell. Sure it's not quite as light as balsa COULD be but at 2 lbs for the frame so far you're not far off what I've seen some folks build there models at when using balsa.

Don't add too much more and you'll be fine. At 432 and figuring a 4 1/2 to 5 lb RTF weight it won't be a glider but it should fly fairly well. The 40 will be more than you need but watch your landing speeds. Learn the stall charactaristics at least 3 mistakes high. And since it'll have a bit higher wing loading than optimum be sure to include about 3 degrees of washout in the tips to control tip stalling for easier landings and initial climbouts.

Back in the dark days of WW2 balsa was being used for life jackets and other wartime uses so modellers learned to use pine and spruce. If you have access to a bandsaw you can cut the wood down to 1/16 and 3/32 veneers for ribs and other parts that need some sheet stock. And don't forget that folks have often used corrugated cardboard for ribs and bulkheads in model construction with good success. Look around and don't be afraid to experiment.

And here's hoping you and all the rest will all be home before you can manage to build the next one. Good luck, keep your head down and think cool thoughts.... We're saving all the GOOD balsa for when you get back home...


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scratch building without balsa - 7/13/2003 2:55:52 PM   
Woodsy



Posts: 1719
Joined: 9/24/2002
From: DrouinVictoria, AUSTRALIA
Status: offline 		i thought the spruce goose was Howard Hughes? or did he just finance it


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scratch building without balsa - 7/13/2003 6:02:55 PM   
BykrDan



Posts: 279
Joined: 1/17/2003
From: OH
Status: offline 		Zhanx,

Your model sounds like it's doing better than my all-hardwood GeeBee (408" sq, 2.5 lb dry weight).

I haven't flown mine yet, but I've got motor and batteries on the way (I have every confidence it will fly!)

If mine will fly, your's will certainly fly!

Dan.

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sheeting - 7/13/2003 8:37:35 PM   
ProfLooney



Posts: 2413
Joined: 1/18/2002
From: Moline, IL, USA
Status: offline 		I did this once and it may sound funny but you could sheet the thing with posterboard and then use polyurethane or equivelent to seal it. or possibly use Obechi veneer for sheeting and stuff.

Joe

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scratch building without balsa - 7/13/2003 10:41:40 PM   
BMatthews



Posts: 8951
Joined: 10/4/2002
From: Burnaby, BC, CANADA
Status: offline 		[QUOTE]Originally posted by Woodsy
i thought the spruce goose was Howard Hughes? or did he just finance it [/QUOTE]

Different airplanes, same names.

Northrup's Spruce Goose was a model biplane with a 60 IIRC. It WAS a large model by today's standards being about 72 inch span so the two aircraft shared that at least.


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Bruce-
Proudly wasting balsa since 1965.

Free Flighters go that extra mile........

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making progress - 7/13/2003 11:48:41 PM   
zhanx


 

Posts: 12
Joined: 7/11/2003
From: stuck in kuwait right now
Status: offline 		[QUOTE]Originally posted by BykrDan
Zhanx,

Your model sounds like it's doing better than my all-hardwood GeeBee (408" sq, 2.5 lb dry weight).

I haven't flown mine yet, but I've got motor and batteries on the way (I have every confidence it will fly!)

If mine will fly, your's will certainly fly!

Dan. [/QUOTE]

i got my engine today made a test engine stand for it and did the initail run-in. I got an O.S. 50 sx which should power it fine. got the body finished.. just need to finish the wings and cover them both.., only problem is the only real covering i got is a thicker food wrap we can get from the chow hall, which should work fine.. gonna do a test on a test frame with a heat gun and different glues (only got super glue, white wood glue and epoxy) and see how it works.. or should i use paper got lots of basic white paper. got a some polyurethane think i should seal the plane with before covering?

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scratch building without balsa - 7/14/2003 12:06:13 AM   
susquach


 

Posts: 294
Joined: 1/15/2003
From: kerrville, TX, USA
Status: offline 		More on the Spruce Goose,

I have the construction article and it demonstrates how to correctly proportion hardwoods in a .60 size plane. Northrup used balsa for sheet chores, stating that balsa is hard to beat for some jobs.
For whatever it's worth, 3/16" foam core board works fine for wing ribs. Used it on a .40 size turbulent with no weight penalty to speak of. Have also used it to "double" 1/16" balsa sheet. If you soak the board in a tub for a short while, you can strip the paper backing off, replacing it with balsa sheet /epoxy glue. Not a big improvement over balsa sheet...just different. The board can be had in scrap sizes for a very reasonable price from picture framers.
Any rate, you've posted an interesting subject. Will stay tuned to see what ideas you come up with.

ddubya

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Re: making progress - 7/14/2003 6:46:09 PM   
BykrDan



Posts: 279
Joined: 1/17/2003
From: OH
Status: offline 		[QUOTE]Originally posted by zhanx
...just need to finish the wings and cover them both.., only problem is the only real covering i got is a thicker food wrap we can get from the chow hall, which should work fine.. gonna do a test on a test frame with a heat gun and different glues (only got super glue, white wood glue and epoxy) and see how it works.. or should i use paper got lots of basic white paper. got a some polyurethane think i should seal the plane with before covering? [/QUOTE]

I've heard of people using Saran wrap to cover planes before, mostly on micro and indoor models (so you know it's light!) No need to heat-shrink even, I don't think. Only problem is getting it to stick. Not sure how that problem was overcome.

Paper sounds durable, should have no problem sticking, but it may add more weight than you want to an already heavy plane, particularly if you choose to varnish it. Can you get newspaper? It's lighter, I think, and I believe I've heard of good results using varnished newsprint. I'd certainly put some kind of paint on if I did that!

Hang in there - I heard of a guy in the reserves who made a functional hot air balloon out of dry-cleaner garment bags, popsicle sticks, and birthday candles!

Dan.

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scratch building without balsa - 7/14/2003 10:52:35 PM   
mikenlapaz



Posts: 1947
Joined: 12/6/2002
From: La Paz BCS, MEXICO
Status: offline 		Do the women in Kuwait use silk for things like scarves, or blouses and shirts? Needed sail material for a small sailboat and ended up cutting up an old shirt. Could be real colorful!


< Message edited by mikenlapaz -- Jul 14 2003 6:11PM >

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