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Old Mar 15, 2014, 03:21 PM
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F-35b VTOL

I'm stepping a bit out of my comfort zone by building this, as I usually build WWI wooden gassers, but I recently decided I want to build something I can fly whenever, wherever, and is relatively fun, so I decided on this 1/12th scale F-35b capable of VTOL. I will build it out of fiberglass from a foam mold, which is a completely new thing for me, any help would be appreciated.
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Old Mar 15, 2014, 11:20 PM
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How long of a flight time are you looking for?
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Old Mar 15, 2014, 11:32 PM
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Quote:
Originally Posted by JakeL17 View Post
I'm stepping a bit out of my comfort zone by building this, as I usually build WWI wooden gassers, but I recently decided I want to build something I can fly whenever, wherever, and is relatively fun, so I decided on this 1/12th scale F-35b capable of VTOL. I will build it out of fiberglass from a foam mold, which is a completely new thing for me, any help would be appreciated.
Would this be your first VTOL? If so you are taking on quite a lot. I would never want to discourage anyone, but you might want to start with something that is both easier and more crash worthy (if this is your first).
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Old Mar 17, 2014, 08:10 AM
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for a flight time, im not looking for anything fancy, just 5-10 minutes, and I hae not done a VTOL before, but I have pretty good resources on how to do it.
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Old Mar 17, 2014, 01:07 PM
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Unfortunately 5 minutes would be a phenomenal flight time for a ducted fan F35 build. You will be lucky to get 2 minutes without damaging your battery. Some type of build that uses props, like LeadFeathers F35, will give you a much better flight time in the range you are looking for.
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Old Mar 19, 2014, 08:52 AM
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OK, since this is a build thread, I'll post some pictures of the build as I go, this is just the basic system for a full size F-35b
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Old Mar 19, 2014, 09:36 AM
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Jake,

This is a very ambitious project. The problem most run into with a ducted fan design such as yours is that power to weight required is not sufficient with the available ducted fans/motos/escs/batteries.

For most VTOL projects I recommend building the hovering platform and get it working separately, and the fixed wing platform and get it working separately, then if each much smaller project is successful you can merge the two to creat a VTOL.

For your F-35 project I would suggest building a really simple and light weight frame to mount the ducted fans and batteries servos controls, etc. and get it hovering well. Then you can start adding weight to see how much F-35 airframe you could lift in addition to the hovering bits. This will save you many hours and many dollars.
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Old Mar 19, 2014, 10:02 AM
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Amen to what Leadfeather said.

Also, turning ducts are hard to make with low losses. A more viable plan is to have the entire EDF in the tail pivot. Two separate small EDF's in the wings for roll control are also much more likely to work than trying to tap off of one of the main lift EDF's.

4 EDF's make it more like a quad-copter and solves some of your control problems, though yaw is still problematic.

You are jumping into the deep end here. Have fun!
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Old Mar 20, 2014, 09:23 AM
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Thank you leadfeather, I agree totally. I have seen that in other threads, and I guess thats the best thing to do, and I'll get right on it.
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Old Mar 20, 2014, 09:27 AM
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could i possibly use a board from a quad then?
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Old Mar 20, 2014, 09:44 AM
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could i possibly use a board from a quad then?
I would get a KK2.whatever and flash it with OpenAero2-VTOL code. I am not saying that you could not get there another way, but OpenAero2-VTOL is such an obvious choice.

The firmware and the user manual are located at the end of the first post here.

http://www.rcgroups.com/forums/showthread.php?t=1972686
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Old Mar 21, 2014, 06:33 PM
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I am, to a point, building on a budget, so is there a relatively cheap KK2 board out there that would do the trick?
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Old Mar 21, 2014, 07:44 PM
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I agree. That's what I did with mine. Got the platform test bed working great but lost interest. Not to discourage anyone but projects like the f35 and harrier have been attempted by so many and are virtually never completed or are not successful. Having attempted many vtols including harriers, ospreys, and f35s, I would definitely suggest making sure this is how you want to spend your time and money before going full steam ahead lol.

Quote:
Originally Posted by leadfeather View Post
Jake,

This is a very ambitious project. The problem most run into with a ducted fan design such as yours is that power to weight required is not sufficient with the available ducted fans/motos/escs/batteries.

For most VTOL projects I recommend building the hovering platform and get it working separately, and the fixed wing platform and get it working separately, then if each much smaller project is successful you can merge the two to creat a VTOL.

For your F-35 project I would suggest building a really simple and light weight frame to mount the ducted fans and batteries servos controls, etc. and get it hovering well. Then you can start adding weight to see how much F-35 airframe you could lift in addition to the hovering bits. This will save you many hours and many dollars.
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Old Mar 21, 2014, 08:00 PM
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Originally Posted by JakeL17 View Post
I am, to a point, building on a budget, so is there a relatively cheap KK2 board out there that would do the trick?
The KK2.1.5 board is available from HobbyKing for about $30. All of the KK2.n boards are about the same price, but the older versions are generally not available anymore. Even the KK2.1.5 seems to be on back order half the time.

All that being said Tumbler makes a very valid point. If you are on a very tight budget then you might think seriously about spending your hobby dollars in some other way. Taking a project like this all the way to a successful conclusion is likely to be expensive in both time and money. You might expect to spend the next 2 years on it and a few thousand $ along the way. I would hate to discourage anyone, but if it is something you really love, then I couldn't stop you if I wanted to.
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Old Apr 03, 2014, 10:37 PM
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OK, It's been awhile, but I'm getting the components for the project, and I have cut out the foam plug pieces. In terms of scale, I want something in between an RC Powers foam box and a super-scale top gun winning design, I want all the curves, but not necessarily the rivets.
Also, I have changed the scale from 1/12 to 1/18
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