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Old Feb 02, 2012, 05:37 PM
Pusher jets rule!
crxmanpat's Avatar
Mesa, AZ
Joined Jan 2006
17,212 Posts
Nick,

5mm foam board will work just fine.

Pat
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Old Feb 02, 2012, 05:51 PM
Fidler & twidler
empeabee's Avatar
Cranfield U.K.
Joined Mar 2004
3,993 Posts
Quote:
Originally Posted by nicksc View Post
Ok Guys, i get the message, balsa is a rude word right!

How about 5mm foam board. I can get that easily. 6mm Depron seems hard to find here in Mallorca.

Thanks

Nick
Ahha I see why you asked, not exactly a world manufacturing centre.
Foam board comes in many types & grades.
Some people used to soak the paper covering off some types of foam board and use it naked - the type I looked at was very 'crisp' e.g. brittle but it might be worth having a look - weigh it in comparison with Balsa.
Pity you can't find where the foam food boxes are made - that is a grade of depron
Traditional frame & 1.5mm balsa skins for the fusealage could work, with a hard 6mm square leading edge on the wing..
Mike
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Old Feb 03, 2012, 01:15 AM
Registered User
Mallorca, Spain
Joined Dec 2009
35 Posts
Thanks Mike and Pat for your help

The foam board i have has a hard, smooth plastic like skin, not paper. but is very strong and there is no flex to it.
However it weights about 3 times that of unskinned Depron.

The sheets i have measure 100cm x 70cm and weight 500 grams!

My thinking with Balsa was to use perhaps 2-3mm sheet, edge joined for the larger areas like wing etc with a 1mm light ply doubler for strength. 3mm for the fus with triangle stock for the corners.

This should provide a strong and reasonably light airframe.

Anyway, i would welcome any more thoughts you might have.

Nick
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Old Feb 03, 2012, 06:38 AM
Fidler & twidler
empeabee's Avatar
Cranfield U.K.
Joined Mar 2004
3,993 Posts
Quote:
Originally Posted by nicksc View Post
Thanks Mike and Pat for your help

The foam board i have has a hard, smooth plastic like skin, not paper. but is very strong and there is no flex to it.
However it weights about 3 times that of unskinned Depron.

The sheets i have measure 100cm x 70cm and weight 500 grams!
!
Quote:

My thinking with Balsa was to use perhaps 2-3mm sheet, edge joined for the larger areas like wing etc with a 1mm light ply doubler for strength. 3mm for the fus with triangle stock for the corners.

This should provide a strong and reasonably light airframe.

Anyway, i would welcome any more thoughts you might have.

Nick
sounds good, though I'd go for 6mm soft balsa for the wings, keeping the carbon tube spar & hard 6mm square Leading Edge - but its your plane, not mine
Maybe the Maestro - Jetset44 - will fly by with comments
Mike
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Old Feb 06, 2012, 02:09 PM
if its not broke,fix it anyway
Biffda's Avatar
United Kingdom, England, Coventry
Joined Jan 2012
146 Posts
here we are my f15 eagle, a big thanks to steve (jetset44) for the free plans looking foward to doing more thanks again steve. Name: IMG_0395.jpg
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Description: my first proper scratch build, grey instead of blue

Name: F-15_Eagle_USAF_Photo.jpg
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Description: pic i used for camo
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Old Feb 09, 2012, 12:30 AM
Park Jet Guru
jetset44's Avatar
Seattle, WA
Joined Jun 2002
5,608 Posts
Nice work, Biffda! And thanks for sharing the pics!
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Old Feb 09, 2012, 12:41 AM
Park Jet Guru
jetset44's Avatar
Seattle, WA
Joined Jun 2002
5,608 Posts
Quote:
Originally Posted by empeabee View Post
Maybe the Maestro - Jetset44 - will fly by with comments
Mike
Yes, I've seen a few guys build park jets with balsa. It's doable, but generally results in a much heavier model than foam that doesn't fly as well. I'd recommend either finding a way to skin that 5mm foam board you have or mail-ordering some 6mm Depron. Once you try building with foam, you'll have a hard time going back to balsa--I sure did!

Just for reference, good contest-quality balsa wood 6mm thick weighs about 0.185 oz per sq in, whereas 6mm Depron weighs about 0.0046 oz per sq in. That means balsa is 4 times heavier than the equivalent thickness foam! But the foam requires more strengthening, of course, using carbon tubes. And/or you can use thinner balsa. So in reality the balsa airframe would probably weigh only twice as much, but that's still a big difference. Super lightweight airframes is why park jets fly so well, and also why they do so well with only the flat plate wing. A balsa version would fly, but not nearly as well and certainly wouldn't be a park jet (i.e. capable of flying in small fields).
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Old Feb 09, 2012, 04:14 PM
Registered User
Mallorca, Spain
Joined Dec 2009
35 Posts
Hi steve, thanks for your comments and i do agree.

However for interest i just madiened a Mig 29 from Tomhe design that i made from Black foam board. No carbon wing rod required.

Flying weight came out at 700 grams!

Using 2217.04 motor producing 290 watts on 6x 4 prop. 2200 batt.

Amazingly she flies really nice and loves wind. She even floats in for landing, hovers and then drops softly on to the grass!

Joined ailerons and elevators together, great roll rate.

I will now try the NAC designed Skyray in Balsa due to its large wing area and see how that works. Will cover in solarfilm. Then i will try one of your designs for comparison. Probably the F15.

Nick
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Old Feb 09, 2012, 08:20 PM
Registered User
Canada, ON, Newmarket
Joined Dec 2005
105 Posts
Here's my winter project. Just love Steve's designs.
This one has Turnigy 2836 2350kv with a 6x5 prop producing 375W on a Nanotech 2200mah 35-70C battery. The plane is made of 1/2" blue styrofoam and covered in 3/4oz glass with WBPU. Weight minus battery is 750gm. 925gm with battery. Thrust to weight ratio is over 1:1.

This may be straying a bit away from the parkflier idea but, it still is a great flying plane. Just need warm weather to start painting.
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Last edited by gdimonte; Feb 09, 2012 at 08:22 PM. Reason: additional notes
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Old Feb 10, 2012, 01:14 AM
Park Jet Guru
jetset44's Avatar
Seattle, WA
Joined Jun 2002
5,608 Posts
Wow, great looking F-15, gdimonte! Excellent job with the fuselage shaping and wing/fuselage/nacelle blending, I know that isn't easy to do. Ain't nothing wrong with straying from the park flier roots of this model, it's great to see the design taken to the other end of the spectrum, too!

If I had the time, I'd love to redo and improve the F-15 park jet design. The original was intended to be quick build and light, and as a result is very boxy. After developing the F-22 and Su-37 park jets, I learned how to make more complex curves without much extra effort, so I'd really like to apply those lessons to the F-15 and do a more proper job replicating the lines and curves of the real thing, just like you've done here. The F-15 is a beautiful aircraft, and certainly deserves that in a scale model!
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Old Feb 10, 2012, 12:21 PM
Registered User
Waltjg's Avatar
Crystal River Fl.
Joined Jul 2008
3,681 Posts
Gdimonte, great looking F15,, I love this plane, it was my very first park jet, and very first electric venture, a test, and from then till now, I only fly electric(unless I'm training someone that has a nitro plane), and still loving building from FFF!!!! Fill in your location, you say it is cold now, so I guess your in the north somewhere... Also, is that an unfinished F4 I see leaning against the wall back there?! .. they are a fantastic looking plane, have a look,, http://www.rcgroups.com/forums/showthread.php?t=1289658 had to take a break from this one, but back on it now... so you see what this F15 leads to! Again, great looking build! w.
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Old Feb 11, 2012, 10:14 AM
Registered User
jeffsch's Avatar
Seattle, USA
Joined Oct 2009
859 Posts
gdimonte, +1 to Steve's comments on your shaping; really takes the appearance of the plane to the next level. Nice job!
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Old Feb 14, 2012, 02:09 AM
Registered User
Son of Alpea41's Avatar
United States, CA, Chino
Joined Apr 2010
145 Posts
I started a 100% F-15 out of Bluecore today.I cant post any pictures now but will soon.
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Old Feb 15, 2012, 06:08 PM
absolutely maybe
pistnbroke's Avatar
Australia, WA, Currambine
Joined Apr 2011
553 Posts
first timer

Hi All,

I have just embarked on building my first scratch build, Mr Shumates designed F-15.
I have read most of the thread and the photos of the models on here are just unbelievable, real works of art!

Being my first build, mine is not pretty, especially the canopy.

Like thousands of others on here, I would like to thank Mr Shumate for the fantastic plans/ design, so far, it has been a very simple construction. My biggest problem is the painting of the model when it's time for that ((colour scheme) I'm not too creative in that area)

I look forward to showing off my "Master Piece" in due course, I think I will take pics from about 100 feet away with a very soft focus .. lol

I would also like to thank all the contributors on here for your building and flying experiences with this model as it has inspired me with some confidence.

Regards

Ian
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Old Feb 15, 2012, 08:57 PM
Registered User
Waltjg's Avatar
Crystal River Fl.
Joined Jul 2008
3,681 Posts
Welcome Ian! This was my first plane I built on here. Steve has great designs, especially this one fun to build looks good and flies great too! I feel your pain on the paint and finish, I have no imagination there either! Good luck build and have fun! W.
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