Project F-14 Tomcat

Roonie

New member
I'm not familiar with frSky. With that said, here's how I would do that on Graupner (will not apply if there is an easier solution):

Add a mix of the wing sweep channel to itself that is only active when the flaps are down. Set the dual rates to -100% (effectively nullifying any movement on the channel when the flaps are deployed) and set the offset to keep them in the unswept position. Of course, do this without the model powered up and look at the channels on the TX to verify it won't try to break anything before trying it with the model turned on.

Good idea. I tried this on my dx8e and it works. Only thing is when flaps are deployed and you switch your wing. The flaps go back to neutral, and ofcourse that also goes when you first deploy the wing and then switch the flaps in the mix sends the wing back to neutral. Beter would have been if just nothing happend. But I cant seem to get that to work with my radio.
Still this is a nice solution. (y)
 

speedy7385

Active member
Woah that's quite a task you are about to take upon you. Just use a fine toothed blade, a coarse one can cause delamination on the cut edges. Also its highly recommended to use water while cutting to prevent dust from getting in the air
Is there a way to convert all those carbon fiber parts into 3D print files (.stl)? Would like to try to print those out with PETG or NylonX.
 

tamuct01

Well-known member
Is there a way to convert all those carbon fiber parts into 3D print files (.stl)? Would like to try to print those out with PETG or NylonX.
You could import the plate drawings as a canvas in Fusion 360, trace them out and extrude them to the proper thickness. I'm not sure that the 3D printed parts would have the necessary torsional rigidity. If you try it out, let us know how it goes. I also have a 3D printer, but no laser/router to cut out the parts from CF.
 

speedy7385

Active member
You could import the plate drawings as a canvas in Fusion 360, trace them out and extrude them to the proper thickness. I'm not sure that the 3D printed parts would have the necessary torsional rigidity. If you try it out, let us know how it goes. I also have a 3D printer, but no laser/router to cut out the parts from CF.
Thanks for replying. I current don't own the Fusion360 program. Will look into pricing of the software.
 

tamuct01

Well-known member
Thanks for replying. I current don't own the Fusion360 program. Will look into pricing of the software.
For hobbyists, there is a free version that has reduced functionality. If you're new to CAD, there are a ton of YouTube videos out there on Fusion 360 to get you started.
https://www.autodesk.com/products/fusion-360/personal

If you have an EAA membership there is a discounted option for Solidworks. The software only works on Windows, though. https://www.eaa.org/eaa/eaa-members...works-resource-center/eaa-solidworks-standard
 

speedy7385

Active member

Flitedesign 3d

Elite member
Is there a way to convert all those carbon fiber parts into 3D print files (.stl)? Would like to try to print those out with PETG or NylonX.
Actually you can directly import the dxf in fusion and then extrude the contours of that imported sketch. 3d printed wingmount is something I have been thinking a lot, even before I decided to go with the carbon version. The problem with plastic is that it yields at very low stress. But I think it is possible to make one if you make it thicker than 2 mm. I'm sure it will be heavier and it will flex more but It sure could work. If you want to make one I'm definitely very interested to see how it works
 

Roonie

New member
Damn, that was quite the build. Loved it. I think she came out quite good , some decals could have been beter but it`s been long enough.
And she is a bit heavier the the original .... about 2500 gr. :oops: But she is rocking 2 64mm 2400 KV 6S 12 blade edf`s with about 3000gr of thrust !!
20220204_150651.jpg
She is ready to maiden ... I`m not though yet. Don`t want to damage her, what wil happen once I try too land.
Also have to wait for beter weather. In the mean time going to build something simpler like this Baron Beechcraft.

And again thanx to @Flitedesign 3d for the incredible plans (y)
20220204_150735.jpg
 

Flitedesign 3d

Elite member
Damn, that was quite the build. Loved it. I think she came out quite good , some decals could have been beter but it`s been long enough.
And she is a bit heavier the the original .... about 2500 gr. :oops: But she is rocking 2 64mm 2400 KV 6S 12 blade edf`s with about 3000gr of thrust !!
View attachment 217909
She is ready to maiden ... I`m not though yet. Don`t want to damage her, what wil happen once I try too land.
Also have to wait for beter weather. In the mean time going to build something simpler like this Baron Beechcraft.

And again thanx to @Flitedesign 3d for the incredible plans (y)
View attachment 217910
That looks very nice, well done! I have no doubt that it will fly at 2,5kg, especially with 6 cell power. It will just be slightly less agile, but that's fine since this model isn't supposed to be that aerobatic anyways. What motors are you using? Qx? You might want to measure the static thrust of the finished plane because it will be quite a bit lower than on bench, especially on 6s setup. There are the cooling grill 3d print files in the plans, they can also be used as cheat intakes if necessary. If you are unconfident about the maiden flight, I recommend flying only on extended mode at first, on that mode its a very docile plane. Landing this plane should not be a difficult task, it has good stall characteristics on extended mode, I don't think it has ever tip stalled on me. How did you make the wing mount? did you really cut that out with a jigsaw?
 

Roonie

New member
Thanx ....
The 64mm edf`s are indeed QX from AliExpress. I measured the thrust after I installed them in the model. I can`t measure that on my work bench. Now I just put the model with it`s nose on the kitchen scale and full throttle :)
I have some cheat intakes on the bottom where you designed 2 slot to hold the plane for hand launching, right inside I made openings in the engine bay.I think you really need them especially with 6S. I had to make them on my F22 too, it really increased the thrust.
I eventually made the wing mount with plywood and aluminium and 4 little ball bearings, Not as good looking as yours but quite
strong no wing flapping..... And yes I did jigsaw the wood and alu by hand :eek:.
The 2mm carbon fiber from AliExpress also took way too long to get here....

With the first flight I just keep the wings forward... and only swing them back at altitude.
 

Crapotte

New member
@Flitedesign 3d, well first of all, what an amazing job you did on the build process and the plans, photos and build log , thanks for sharing those. I am starting to build slowly the F-14 you designed with great interest. I already cut the 7 sheets of foamboard, waiting on some plywood and carbon fiber to come in, ordered some 4s 64 mm fms fans, my question was more towards radio setup. How did you setup your radio? How many channels? Elevons or elevator and ailerons ? and do you deactivate ailerons when you sweep the wings and turn into elevons ? Thank you For your great work !
 

Flitedesign 3d

Elite member
How did you setup your radio?
I propably should have done a detailed explanation of configuring the radio at the time I released the model, its a long one but here it is.

So first of all, I'm using a frsky radio running opentx firmware. I have 7 channels and 6 inputs in use. 4 inputs for the conventional controls, one 3 pos switch for flapperons and one 3 pos switch changing between the 3 flightmodes. Sweep angle is determines by flightmode. The reason why the wings are controlled via flightmodes is because it allows for the use of different throw limits, expos and elevator trim for each wing position. Thats quite important since its way more roll sensitive with a high sweep angle. It also allows the flapperons to work only in the extended mode. This is also important since the flaps are physically prevented from being in the down position while the wings are retracted. Elevator and ailerons are mixed together to elevons, flaps and ailerons are mixed together to flapperons while the rudder is just minding its own business.

So this is the goal of how it should behave, now this is how I configured it in the transmitter. Im not sure how firmware specific this is but Im guessing its very similar in all opentx controllers. (Note that this is most likely neither the only nor the best way of doing this but its how I did it)

3 different flight modes, 0, 1 and 2 respectively corresponding to extended, half swept and full swept.
fm0 trims are set to 0, 0, 0, 0 which are respectively the common aile, ele, tro, and rudd trims of flight mode 0.
fm1 trims are set to 0, 1, 0, 0 which means it is using its own elevator trim, other trims are the common fm0 trims. Correspondingly
fm2 trims are set to 0, 2, 0, 0
Each flightmode has a fade in and fade out time of 1 sec to make transitions more smooth.

6 inputs: (number refers to amount of throw, exp number refers to expo curve weight)
Aile100, exp 70
Ele100, exp 70
Rudd100
Thro100
Flap50 (Throw limitedto 50% combined with an offset to prevent the flap from going in the reverse direction)
Swe100

Mixes: (number -100 to 100 refers to the amount of throw)
CH1:

For fm0: Ele-100, Aile100 (Equal throws for elevator and aileron)
For fm1: Ele-100, Aile60 (Less aileron throw on fm1 and 2)
For fm2: Ele-100, Aile50
Ch1 physically connects to either elevon servo

CH2: Same as CH1 but one reversed:
For fm0: Ele100, Aile100
For fm1: Ele100, Aile60
For fm2: Ele100, Aile50
ch2 connects to the other elevon servo

CH3: Throttle, nothing to mix

CH4: Rudder, nothing to mix

CH5:
For fm0: Flap100, Aile100
For fm1, 2: Either nothing or in my case I put Flap0 (0 throw) but with a slight offset so the flap is positioned just right when it slides
inside the cover.
ch5 connects to either flapperon servos

CH6: Swe90, adjust this throw so such that the wings fully extends and retracts but the servos doesn't scream in pain at maximum travels
2 seconds of slow up and slow down to make the wings retract slower
ch6 connects to both wing servos

CH7: Same as ch5 but flap reversed:
For fm0: Flap-100, Aile100
For fm1, 2: As above
ch7 connects to the other flapperon servo


I hope this helps. Remember that all the throw limits, expo weights etc. values are there just to give you a starting point. You can try different values that works for you. These values were a guess of mine and they weren't terrible so I kept them.
 

Crapotte

New member
Wow, that is real valuable info. Thanks for sharing and taking your time to answer. I will clearly share what my progress is as far as i go. Currently i only have cnc’ed the 7 sheets of foamboard and since my laptop quit on me last night. It will take a fee days until i get back to business and cutting plywood. I intend to use carbon fiber epoxiedcand sandwiched between 2 layers of 2 mm ply instead of only plywoo. but overall will be following your guideline and recommendations. Thanks again for the info and your time!
mat
 

Crapotte

New member
Finally got to work a little bit on the project. All foamboard sheets are cnc’d,
4mm plywood parts lasered (2 layers of 2mm plywood laminated)
2mm carbon sheet substituted with what i had on hand. So 2mm plywood laminated with 6oz twill carbon fiber and epoxy. Total part thickness around 2.5mm and plenty stiff.
3d printed parts done out of ABS.
have great holidays!
 

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MystRacing

New member
So I decided to take the plunge and build one of these. I got to thinking today that I don't know where the CG on this plane needs to be located. Any help with that would be much appreciated.

Thanks to Flightdesign 3D for the plans, and particularly including the DXF files etc. I'm actually upsizing it about 10% to fit 70mm EDF's.

I've been kind of working on it for about 6 months. What that means is upgrading a 3018 to good enough spec to cut the carbon fiber etc. I've started on the foam portion and am ready to start on the engine tubes.

Here's a photo of my 3018 and the plywood and CF parts I cut on it.

i-XcBQz8F-L.jpg


The plywood parts

i-4p4th4C-M.jpg


I printed a tray to cut the CF under water so there was no dust.

i-gtC5JgX-M.jpg


And here's the parts

i-TCBfDFH-M.jpg
 

Crapotte

New member
Hey guys.
Finally got around building m'y first part of the tomcat... Hopefully i Will be able to continue before 6 months🤣.
Plastic molded vacuum formed canopy on the diy machine and 3d printed pilots. Could have been better but wont see them at 100kph anyway 🤣
 

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MystRacing

New member
That looks awesome, great job! I'm not brave enough to get that fancy any longer, the last plane I put that much effort into went hard into the ground on the maiden flight. Decided I'd try and fly mine before I get to decorating it. I burned up one of my wing sweep servos trying to reverse it so I'm at the point of waiting for a replacement. Should be here in a couple weeks. Wont take long to finish it from this point.

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