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Old Sep 30, 2012, 08:12 PM
What tree??.......Doh!!
Smokin_Joes's Avatar
USA, WA, Seattle
Joined Aug 2007
765 Posts
Vic- Looks awesome bro!!!

~Cheers,

Neil
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Old Sep 30, 2012, 09:04 PM
Don't Move I've Dropped My Nut
bamaguy's Avatar
United States, AL, Huntsville
Joined Feb 2009
1,849 Posts
Quote:
Originally Posted by boom View Post
18^3 x 10 gives you 58320lb 100% scale weight.
So this model at 15lb is equal to 87,480lb full scale! I doubt that our model will fly at 15 lbs???
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Old Sep 30, 2012, 09:06 PM
6 months to finish a rtf
pulsery2k1's Avatar
upstate ny
Joined Jun 2003
1,860 Posts
Cocg

problem with weight to scale is the model is made of foam
real jet is made of metal.

so thought boom's statement is correct , if you made the full
size jet from foam how much would it weigh ?

See now we can become super rich - if they made the real
ones out of foam with the weight savings ---- comes big
fuel savings - plus the foam is cheaper so jet will be less

lets get Ming to build us some full scale ones

but if you reversed the 18^3 and divided it from the max weight of 133,000 lbs of 737-700
you would get a model of about 22 LBS
about what an aluminum model this size would weigh.
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Last edited by pulsery2k1; Sep 30, 2012 at 09:17 PM.
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Old Sep 30, 2012, 09:22 PM
What tree??.......Doh!!
Smokin_Joes's Avatar
USA, WA, Seattle
Joined Aug 2007
765 Posts
Quote:
Originally Posted by bamaguy View Post
So this model at 15lb is equal to 87,480lb full scale! I doubt that our model will fly at 15 lbs???
I've some rocks if you wanna try?

You guys make me laugh for sure!
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Old Sep 30, 2012, 09:34 PM
6 months to finish a rtf
pulsery2k1's Avatar
upstate ny
Joined Jun 2003
1,860 Posts
Smokin_Joes

well to keep scale , even at 15-20 lbs with flaps and slats
you would have 250 to 380 feet to get off
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Old Sep 30, 2012, 10:42 PM
Fly and let Fly!
Cocg's Avatar
United States, CO, Grand Junction
Joined May 2010
2,438 Posts
Thank you gentlemen for answering some of the odd thoughts of mine.. And amazingly how heavy the 1:1 planes really are.. But still kinda shows me the awe inspiring thing of flight. Yes, 100 years achieved but still ..Have you seen the Boeing flight exceeding 1 million pounds? Wow..!! BTW.. Smokin_Joe, I have a Bomber I have intentions of adding much weight to in experimenting with this kind of thing..!!
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Old Sep 30, 2012, 11:00 PM
Fly and let Fly!
Cocg's Avatar
United States, CO, Grand Junction
Joined May 2010
2,438 Posts
Covering

Quote:
Originally Posted by Future Wingz View Post
Cocg thanks for the compliments this is my first ever Foam/ EDF project and I used vinyl (Oracal 651 White) for the fuse. I'm a newbie when compared to a lot of the super talented builders on this thread and I couldn't have done it without their help on lessons learned. I also couldn't have covered that huge fuse without my wife's help I cut out 8-10 sections of vinyl to cover the whole fuse. Happy building

Cheers!

Vic
Still on the fence... I humbly consider myself a good balsa plane "coverer".. I think I would do OK with the Oracal... Yet.... I like the paintability of Pulserys Tissue and Water based poly... (which I bought today) It appears both will still show panel lines (I like) l'd think handling it might be easier when done but.. but... Ugh..! Me too not a major experienced dude of either.. Noticed in the thread there Future Wingz... You got this plane done pretty quick since it arrived to you..!!.. Cheers back..!!
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Old Oct 01, 2012, 01:04 AM
Paul B
Australia, TAS, Launceston
Joined Dec 2009
352 Posts
Looks great Future Wings!!
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Old Oct 01, 2012, 03:29 PM
Fly and let Fly!
Cocg's Avatar
United States, CO, Grand Junction
Joined May 2010
2,438 Posts
Covering WBP

Maybe silly question.. Polycrylic... Which is easiest to work with... Gloss? Satin? One sand easier or paint adhere better than the other? Or does it matter?
Cliff
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Old Oct 02, 2012, 04:57 PM
Registered User
United States, TX, League City
Joined Jun 2008
368 Posts
Quote:
Originally Posted by Cocg View Post
Maybe silly question.. Polycrylic... Which is easiest to work with... Gloss? Satin? One sand easier or paint adhere better than the other? Or does it matter?
Cliff
IMO it doesn't matter because I lightly sand it back down to smoothen it out before primer and then it gets another light sand before painting
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Old Oct 02, 2012, 07:26 PM
Fly and let Fly!
Cocg's Avatar
United States, CO, Grand Junction
Joined May 2010
2,438 Posts
For Those Who Been There Done That.. THANK YOU..! (Doug)

Preliminary flap cuts.. Not for the faint at heart.. Planes 'Gotta Hav'em!Name: 737 004.jpg
Views: 100
Size: 149.4 KB
Description: Not spoiler intended, but as mentioned.."not too much more work"

Name: 737 005.jpg
Views: 99
Size: 188.7 KB
Description: All edges need cutting in or straightening.. Foam sticking halfway out between flap and aileron will be spoiler "shelf" Outer half still on flap itself so when flaps up it will be flush and full..

Name: 737 006.jpg
Views: 109
Size: 191.9 KB
Description: Flaps yet to be fully beveled. Name: 737 007.jpg
Views: 114
Size: 254.0 KB
Description: The inboards were a challenge! Name: 737 008.jpg
Views: 147
Size: 282.6 KB
Description: Still neeed to cut the "shelf" for inboard spoiler..
Now still have another wing to contend with..

hi2nr.... Ohh boy no slats.. How you doin with them?
I still have no clue what livery
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Old Oct 03, 2012, 02:34 AM
*** gravity sucks ***
Fotor's Avatar
Netherlands
Joined Mar 2007
400 Posts
Some more input on the scale weight discussion.

What is scale weight? For me the airplane is perfectly scale if the speed is scale. So a 1:18 B737 should fly 18 times more slowly than the real thing.
I recently did some math, and found that for scale speed the weight needs to be scale^4 lower than the original weight (assuming that CLmax and other variables are the same). So for scale speed on this model you would need a weight of 133.000 / 18^4 = 1,27 lbs. Impossible to achieve. Scale speed is almost impossible to achieve on anything smaller than, let's take a rough number, 1:3.
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Old Oct 03, 2012, 09:48 AM
NiCd + Mabuchi 550 was da bomb
NY USA
Joined Apr 1999
610 Posts
Quote:
Originally Posted by Fotor View Post
Some more input on the scale weight discussion.

What is scale weight? For me the airplane is perfectly scale if the speed is scale. So a 1:18 B737 should fly 18 times more slowly than the real thing.
I recently did some math, and found that for scale speed the weight needs to be scale^4 lower than the original weight (assuming that CLmax and other variables are the same). So for scale speed on this model you would need a weight of 133.000 / 18^4 = 1,27 lbs. Impossible to achieve. Scale speed is almost impossible to achieve on anything smaller than, let's take a rough number, 1:3.
This is where helium balloon fuselage and depron comes in
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Old Oct 03, 2012, 11:12 AM
Fly and let Fly!
Cocg's Avatar
United States, CO, Grand Junction
Joined May 2010
2,438 Posts
I initially promted the question for I am certainly not paid for my math skills.. But ... Somthin' still doesn't seem (feel) right..!! Really.. Think of it.. Doesn't matter the material, if you could pick up a real 737 how much would it feel that it weighs.. (?).. Too heavy... How would the thing fly? Too light.. Well that can't be.. Hmm..
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Old Oct 03, 2012, 11:50 AM
NiCd + Mabuchi 550 was da bomb
NY USA
Joined Apr 1999
610 Posts
Quote:
Originally Posted by Cocg View Post
I initially promted the question for I am certainly not paid for my math skills.. But ... Somthin' still doesn't seem (feel) right..!! Really.. Think of it.. Doesn't matter the material, if you could pick up a real 737 how much would it feel that it weighs.. (?).. Too heavy... How would the thing fly? Too light.. Well that can't be.. Hmm..
Discounting similitude or any other dynamic factors needed to scale flight or scale aerodynamics, a static fully loaded 1:1 737 zapped with a shrink ray set to 1:18th scale will feel like a 22lb model when you pick it up. Simple as that.
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