HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 18, 2012, 06:31 PM
Registered User
Joined Mar 2002
263 Posts
You do realize how backwards that sounds right? The wing cores are simple by comparison and you would rather make the ducts yourself?

To each his own I suppose. But the duct sections were included in the plans so people without CNC access could make them themselves.
nem3 is offline Find More Posts by nem3
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 19, 2012, 01:00 AM
Registered User
New Zealand, Waikato, Hamilton
Joined Nov 2011
294 Posts
Well I have to wait 3 weeks before the wings get here so I've got to find something to do. How hard can it be? LOL (probably extremely hard) If I glass straight over the foam plug (from the file you gave me) will the duct slide straight into the former's without being loose? BTW if you could help me with the process i would greatly appreciate it.

First Question is what should I spray the foam with so the epoxy doesn't eat it? Second Question is once I've glassed over the foam and the glass has set how do I get the foam plug out? Lastly the Intake duct will need to be in two pieces to be able to slide into the former's should I have the plug cut in two pieces before I glass it or after I glass it?

Cheers,

Matt
1stfoot is offline Find More Posts by 1stfoot
Reply With Quote
Old Jan 19, 2012, 02:29 AM
Registered User
kanji's Avatar
Finland
Joined Nov 2007
313 Posts
Quote:
Originally Posted by 1stfoot View Post
First Question is what should I spray the foam with so the epoxy doesn't eat it? Second Question is once I've glassed over the foam and the glass has set how do I get the foam plug out?
Epoxy resin doesn't eat up foam. Polyester resin does but if your using epoxy you can brush it straight on the foam plug.

Now you have to decide if you want to use those foam plugs more than once, or use lost foam method to melt the foam plug from your glassed ducts.

I've made decent looking ducts with foam plugs without bother making real mold from the plugs. When foam plug is carved and sanded to shape, I cover it with packing tape. Cover plug as tidy and neat as you can, then brush epoxy resin over the tape and start glassing.

When glassing is almost cured, cut one long cut to duct that runs through its lenght from end to end. I normally cut sidewall of the duct. When glassing is fully cured run your knife through that cut again and peel the duct off from the plug.

Now you can use masking tape to align cut edges together and glass over, either with fiberglass tape or narrow strips of fiberglass.

You can also salvage your plug simply by taping cut on the plug with new packing tape layer and plug is good to go on another batch.

If I want to be super sure that duct comes of from the plug easily, I use wax on the plugs. Wax that I've had success with is Mirrorglaze 8, but almost any karnauba or beeswax will work.
kanji is offline Find More Posts by kanji
Reply With Quote
Old Jan 19, 2012, 02:45 AM
Registered User
New Zealand, Waikato, Hamilton
Joined Nov 2011
294 Posts
Hey,

Cheers for that a few more questions what glass cloth should I be using? and also should I use epoxy or polyester resin?

Cheers,

Matt
1stfoot is offline Find More Posts by 1stfoot
Reply With Quote
Old Jan 19, 2012, 03:12 AM
Registered User
kanji's Avatar
Finland
Joined Nov 2007
313 Posts
Quote:
Originally Posted by 1stfoot View Post
what glass cloth should I be using? and also should I use epoxy or polyester resin?
Use epoxy resin, it doens't eat up foam. If you can get Zpoxy Finishing Resin, thats the simplest way to glass. Really nice stuff when your glassing planes or making small parts.

For glass cloth I would use quite light 80g/m2 (3oz cloth) and get more layers to give better overall streght and rigid duct.
kanji is offline Find More Posts by kanji
Reply With Quote
Old Jan 19, 2012, 03:47 AM
Registered User
New Zealand, Waikato, Hamilton
Joined Nov 2011
294 Posts
Hey,

Unfortunately no one down here sells 3oz cloth should. Go for 1.5oz and do a few layers otherwise I can only find 1oz closest to 80g per sq m I can find is 100g per sq m which one should i for? And how many layers shud I do?

Cheers
1stfoot is offline Find More Posts by 1stfoot
Reply With Quote
Old Jan 19, 2012, 07:15 AM
Aka: Tom Jenkins
ApexAero's Avatar
Palm Beach County, Fl.
Joined Aug 2008
4,494 Posts
1stfoot, 28gr is one ounce, times three is 84gr, times four is 112gr
100gr divided by 28 equals 3.57. 3.57oz glass, two layers done well is light and strong as will be needed. Airsally does the seam with cling wrap so you can peel the part off the duct mold then glue the seam overlap later with CA.
ApexAero is offline Find More Posts by ApexAero
Reply With Quote
Old Jan 19, 2012, 06:49 PM
Registered User
Joined Mar 2002
263 Posts
Great responses guys, thanks for helping out Matt.
nem3 is offline Find More Posts by nem3
Reply With Quote
Old Jan 19, 2012, 10:59 PM
Registered User
New Zealand, Waikato, Hamilton
Joined Nov 2011
294 Posts
Yeah thanks heaps guys, I managed to get hold of some z-poxy finishing resin today looks like it will do the job extremely well, I will have to order the cloth though and I've still got to make the plugs but hopefully shud have the ducts made in the next 2 weeks or so depending on when I can get the plugs made. I also bought the fans, motors and servo's, I chose to go with HET 6904 units and 2W-23 HET brushless motors. Each fan should produce around 3kg thrust on 5S.

Cheers,

Matt
1stfoot is offline Find More Posts by 1stfoot
Reply With Quote
Old Jan 20, 2012, 08:07 AM
it wasn't me flying that plane
Hover or die's Avatar
United States, NC, Wilmington
Joined Mar 2011
705 Posts
nem3,
Is there a place I can find the templates to cutout the parts for your plan?I am very very interested in this build and want to start aanother big F22.
Could any of you guys point me in the right direction to find the templates so I can cutout or inlarge and cutout..
Thanks guys.............................Chris

Incredible work also needs to be said!!!!!
Hover or die is offline Find More Posts by Hover or die
Reply With Quote
Old Jan 20, 2012, 02:06 PM
Registered User
Joined Mar 2002
263 Posts
The "templates" are in the Autocad files located in this thread. As I stated in the first post, please make sure you read the whole thread. See the first post as to why.

This question comes up a lot, and I am thinking of combining all the information scattered throughout the thread into the first post for easier reading. When I have the time to sit down and go through everything I will. But for now you will have to read the thread.
nem3 is offline Find More Posts by nem3
Reply With Quote
Old Jan 20, 2012, 03:35 PM
Registered User
New Zealand, Waikato, Hamilton
Joined Nov 2011
294 Posts
Hey Guys,

Thrust Vectoring Nozzles just arrived from Australia they look good just need a bit of a sand then I will prime them and paint them. Will post some pics of progress soon.

Cheers,

Matt
1stfoot is offline Find More Posts by 1stfoot
Reply With Quote
Old Jan 21, 2012, 06:33 AM
it wasn't me flying that plane
Hover or die's Avatar
United States, NC, Wilmington
Joined Mar 2011
705 Posts
woot woot!!!I finally figured it out...A big thank you!
I will have time tonight to look it over and plan my build...
Nem,
Are you good with me starting a new thread in the Scratchbuild section?This is where I usually do my builds..(or the ones so far..)I was getting ready to start a scratchbuilt F16 but with this type of former/bulkhead work I am honored to give this one a go..Not sure what material route I will go but will hammer out a plan to do so tonight..Probably 9 mil/6 mil/3 mil depron and possibly some 1 or 2 inch blue or pink foam..Probably glass as well at least a thin coat..Dual high output 70's..6s 2000 watts per unit..more than likely.
Once again thanks!I edited this post when I figured out my problem.I still had some downloading work to do..autocad 2012 trial..

I will be sure to give credit for the outstanding work you have done with this plan..

WOW!

Take care...............................Chris
Hover or die is offline Find More Posts by Hover or die
Last edited by Hover or die; Jan 21, 2012 at 11:17 AM.
Reply With Quote
Old Jan 22, 2012, 12:53 AM
Registered User
Joined Mar 2002
263 Posts
Quote:
Originally Posted by Hover or die View Post
Are you good with me starting a new thread in the Scratchbuild section?This is where I usually do my builds..(or the ones so far..)
Not at all. If you wouldn't mind linking back here so others can get the plans (and hopefully read the thread).

Quote:
Originally Posted by Hover or die View Post
Probably 9 mil/6 mil/3 mil depron
+
Quote:
Originally Posted by Hover or die View Post
Dual high output 70's..6s 2000 watts per unit..more than likely.
=

Not so sure that would be the best of ideas. If you're going to go through all that work, I'd suggest going with 1/8" multi-ply. It will be stronger and lighter than a depron build. Especially considering the power system you plan to use. All the reinforcing needed to support that weight and power output. Depron would be great for a dual 55mm edf jet though.
nem3 is offline Find More Posts by nem3
Reply With Quote
Old Jan 22, 2012, 07:29 AM
it wasn't me flying that plane
Hover or die's Avatar
United States, NC, Wilmington
Joined Mar 2011
705 Posts
Morning Nem,
Here is a link to the scratchbuilt Scorpion I did..It was a first here on RCGroups..On the first page you can see the prototype and at the bottom of the first page I start on the Beta build that I continue to fly now..
When I posted above I should have added that I used a lot of ply for reinforcement,fan bulkhead,retract mounts,high stress areas,ect...
And I also plan to use glass on this build..Also "plant" a lot of carbon fiber in my builds..
I used the high output 70 in my scorpion and it is ballistic with nearly 2 to 1 thrust..3 axis gyro,the works...(yes it hovers!)Also uses the lander thrust vector unit..
http://www.rcgroups.com/forums/showthread.php?t=1473787
Please check it out if you have time..FYI,it's the scorpion that Aviation Design builds..(one sexy jet)

I'm also building her a little bigger than the ones you guys are doing but that matters little..
I will certainly do your plan justice,just need to get the ball rolling and learn how to navigate the autocad..(what a cool system!!)

I will be sure and keep you informed on progress and will start a thread over the next 3 days with a link here.....
Thanks and if you need anything just let me know..................Chris
Hover or die is offline Find More Posts by Hover or die
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
F22 Raptor videos outthere? with BL setup dgoderich Electric Ducted Fan Jet Talk 1 Jul 27, 2008 04:49 PM
F22 Raptor stephenzagy Electric Ducted Fan Jet Talk 2 Jul 16, 2003 10:29 AM
F22 Raptor stabilator tips? Basketcase Foamies (Kits) 4 May 28, 2003 06:14 PM
Wattage F22 Raptor Sale/Trade b0gh0s Aircraft - Electric - Airplanes (FS/W) 1 Nov 04, 2002 03:54 PM
F22 Raptor Flys Inverted, into trees... rtucker Foamies (Kits) 4 Oct 23, 2002 10:15 AM