Build Log: BrightStar mk.1 - Twin EDF Cargo Plane

[leighb2282]

Bright-Star mk.1

DETAILS

Howdy Folks, this is going to be a build log for my personal Cargo plane, Peter's Guinea Pig is an awesome design but I wanted to try something a little different.

I wanted to try to design and build a cargo plane from scratch, with my own twist on a cargo plane.

The basic rough concept is a mad love child of a C5 Galaxy, Embraer 390, YC-14 and potentially a little bit of Britten Norman Islander depending on how the build progresses.

FAQ


Will the BrightStar be swappable?
In a way YES! I plan to use the Guinea Pig nacelles dimensions in terms of width and height to allow for a certain compatibility with the dimensions of a power pod but design the nacelles and the power pod specifically fo rthe EDFs i'm going to use (EDF Power pods!)

Differential thrust or rudder?
I Plan for both, with the size its working out to be it may well be very fun to have the ability for differential thrust as much as an EDF will allow.

How many servos will I need?
Currently 5 (2x for Ailerons, 1x for rudder, 2x for elevator) I may well also add flaps before the process is over so 7 servos

What about landing gear?
Initial plans will be for fixed landing gear although I really want to scratch build some form of retracts for it.


SPECS

WINGSPAN	Roughly 60-66”
LENGTH	Roughly 50"
CHANNELS	4-6
Weight	(Potentially a plump bird, my designs are not elegant)
Build Difficulty	Unknown
Build materials	Foam Board Hot Glue CA
Planned Electronics	SPEED - 4S MOTORS - 2x 2x Alloy DPS Series 68mm EDF (66amps max, 4000kv motor, max 1000w, cont 900w) - 1 will be running with a normal impeller/rotor. ESCS - 2x HobbyKing 70A BlueSeries Brushless Speed Controller (cont 70amps, 90amp burst) BATTERY - ZIPPY Flightmax 4000mAh 4S1P 45C SERVOS - Currently cheap 9Gr micro servos, may have to move to some metal geared servos...

PLANS

None Yet, my designs when designing in Sketchup do not follow the plans standards that FT uses.

BUILD LOG

Stay Tuned!


REVIEW


Coming soon.

 

[leighb2282]

Part 1 - Vertical Stabilizer

I started with the Vertical Stabilizer simply because I wanted to start from the back and move forwards, getting the rear control surfaces complete and out of the way.

I chose to go with a T-Tail because a) It looks kinda bad-ass! and b) I've not seen it done before in a DTFB scratch build(it probably has somewhere)

I built out a temporary rear fuse to prototype and build on while i'm making the upper stab, this just gives me a good stable base to test out the servos and control surfaces before I complete the fuse.



Next I printed and scored out the vertical stabilizer, I chose to use a '3d' stabilizer to help with wire routing up to the top of the T-Tail, this brought along issues with the rudder bevels as they would be on the other side of all the other score cuts and bevels but they transitioned very well! You can also see where I had already started to gently fold the leading edge of the stab.




If you look in the second image you'll see yellow areas, these are for braces (yellow for me also indicates that I remove the paper from the foamboard, red is for a bevel, green is for removal for an A or B fold and blue indicates a complete cut-through) these braces also make up the route for the wires as well as a stable brace for the rudder's servo.

at this point I centered the servo and screwed servo horn securely and got glued both sides to the braces, one thing I forgot at this stage is to drill out the servo horn for a linkage stopper so I'm now going to have to either be really accurate with the control rod or now place the linkage stopper on the rudder itself.



This is the vertical stab temporarily affixed to the temporary rear fuse, you can see where the control horn for the rudder comes out, I had to bevel the slot to allow the horn full range of movement, right now from the vertical cable channel backwards it hasn't been glued yet, that will happen in the next sitting before I build and mount the T-Tail upper body that the horizontal stabs will connect to and which will also house the servos for the elevators.



Here you see how the vertical stab sockets into the rear fuse, the straight lines from the yellow channels downwards denote where another wiring channel will be running the length of the fuse to promote cable tidiness (overboard I know but it looks really nice!) there will actually be a 'socket' in the rear of the plane to take different attachments (for a fun example, where you can have a reel of streamers or something)


and finally, a quick shot of how those rudder bevels meet up, this whole inner surfaces will be glued together and the bevels allow for good movement in both directions while setting the pivot point of the rudder in the center of the rudder versus on one side when your doing a rudder made of a single piece of foam.



If you made it this far thanks! I'll see you in part 2!

 

[leighb2282]

Part 2: Horizontal Stabs and T-Tail pod!

With the vertical stab complete I moved onto what would tie the vertical stab and the horizontal stab together - the T-Tail pod! this would house the servos as well as provide a secure attachment point for the vertical stabilizer where it meets the horizontal stabilizer, below is all the pieces all cut out and ready to go! the servos at this point are already hot glued to the sides to facilitate building.



Next you see the braces for the pod as well as the shelf that will support the wings, the slots are for pegs that go through the wing and through this support to increase strength.



Here we are sides all glued in, its a really tight squeeze for those servos! but they are positioned to also provide a nice tight fit for the stabs.



This was a test fit of the wings before I glued them, you can see the little slot I had to cut for the servo horn to be able to fit in such a tight place, but the cut (only about a 3rd deep of the overall depth of the foam) allows full movement of the servo horn, you can also see peg slots on the wings which marry up with the slots on the shelve in an earlier picture.



And here is her nose she has had her upper plate glued on, this is one piece all the way through with the paper peeled off of the front end to promote the pretty radical curve it has to go through, there is an additional length of paper (about 1/2 inch) which got glued down to the bottom once everything curved around, you can also see the bottom route where it mates to the vertical stab and where the wires go through.



And here she is mounted (temporarily) to the Vertical stabilizer, I say temporarily because I want to get a longer y-connector cable for the 2 servos - the current one is to short and I would have to have another extension on to the the Y-cable just to reach where the receiver will be, I do have a design for airfoil horizontal stabs if these prove to be to flimsy but wanted to go with these to begin with, once I get my FT order in for control horns, linkage stoppers and control rods i'll be hooking them up and will post a video of them all working in harmony (or a terrible mess resulting in a redesign)

 

[BigSix]

this is really neat! im subscribed and eager to see how it goes!

 

[AkimboGlueGuns]

How many Edfs will this be? It's starting to look like a C-5.

 

[leighb2282]

How many Edfs will this be? It's starting to look like a C-5.

I'm starting with 2 68mm EDFs which 'should' put out about 1.7kg of thrust each, I will be looking to design the main wings so that if needed I can add 1 more EDF on each wing to bring it up to 4 total but i'm hoping that this will not be necessary (I need to go a bit lighter on the hot glue)

The C5 T-Tail is actually the inspiration behind the one I build (albeit more boxy than the real C5's T-Tail configuration, one ncie thing though is that there is plenty of room inside the pod to add navigation lights If I go that route.

 

[leighb2282]

Some more progress has been made! all the parts I currently have designed have been transferred to DTFB in preparation for cutout, but I got 1 piece cut out and built today, which was the Cockpit/nose area, which will be removable just like the guinea pig's nose.

Here you can see the parts cut out and ready to be built together, those area's that have had their paper removed on the noses are where the shelves are going to be - I prefer locations where I'm going to be wanting to glues pieces to each other to be bare foam rather than the paper which has a tendency to delaminate from the foam (you'll see I do this also at the location where the braces are too!



Next picture shows it all put together, I plan to use Peter's waterproofing / strengthening technique with minwax and the brown craft paper on all the larger pieces (nose, body) which is why i'm not to cut up about the edges of the paper not all tidy, general shape is similar to the Guinea but the 'cockpit' area is at a shallower angle (i think) and it may be a little longer too, not sure since I don't actually have a guinea... You'll also notice i don't have any taper on the width of the nose, this is simply because i'm not good enough with Sketchup to be able to handle all the additional curves that including that narrowing would need.



Finally, a look inside, the first part is what sockets onto the body, the first level of the shelf is actually the same height that the floor of the body socket, it all goes well this will be where the batter will be housed, I wanted the floor to be the same level so I can move the battery however I want in this space and it would still be the same level even if it was moved further forward. that little higher shelf in the nose is mainly in there for structural purposes but could conceivably be used as a floor for an FPV setup like a gopro or mobius or even a board camera setup of some sort!



So, now we have the nose and the tail the next logical step is the body! which will be coming along in the next few days, the body buildup will probably come in multiple steps as my design is pretty involved and I would like to take a decent amount of pictures without peppering just 1 posts with a ton of them.

 

[ZoomNBoom]

View attachment 54635

Glancing over the thread, I saw the above image and thought: that looks quite neat.
Not realizing it wasnt a plane, but only the horizontal stabilizer lol.

 

[leighb2282]

Glancing over the thread, I saw the above image and thought: that looks quite neat.
Not realizing it wasnt a plane, but only the horizontal stabilizer lol.

I actually found out when prototyping this part of my build that one of my earlier versions fit a FT mini power pod perfectly in that tail pod, so I ended up making a mini plane out of it (http://forum.flitetest.com/showthread.php?21974-Scratch-Build-Tractor-Canard-Mini-Plane-ala-Punjet) removed the front nose and added the mini power pod, and added canards and winglets.

I've yet to see how well it flies (if at all)

 

[Spastickitten]

Sad to say this, but black foam board paper falls off easily, so if you can, try white.

 

[leighb2282]

Sad to say this, but black foam board paper falls off easily, so if you can, try white.

I have used the white before (its what I started with) but Dollartree was out of white foamboard in the store that is near my house when I started this particular build so I tried the black, its not to bad but the paper does seem to not be adhered as well.

When it comes to the wings (and from now on if I can help it) I'll be moving to white foam!

 

[leighb2282]

Small amount of updates currently but I wanted to update the thread.

All of the airframes parts are now cut out and I started on the main airframe build, I have 2 of the 3 internal braces glued in, the 2 braces I now have in also hold in the floor/ceiling for the electronics for actual RC flight as well as the 'module bay' below that, and I have glued the bevels for the rear end of the airframe to aid in gluing of the b-fold.



Here is the bottom of the airframe with the module bay exposed, those 2 square holes in the middle are incase I need access from the bay to the rest of the airframe cavities, the smaller holes will actually be used to hold the module in the module bay and will secure the module in the equipment cavity.



This next images shows the rear part of the airframe, in this incarnation I don't plan to have anything here for now but there is plenty of room for a rear cargo door like the Guinea pig down the road, Instead of having wires just hanging down I chose to add a little enclosed wire channel on the upper ceiling of the airframe, this keeps all the wires nice and neat and will be especially useful if I do add a cargo door in the 'butt' of the plane, the u-shaped pieces of foam are parts of the landing gear retainers which are not complete yet.




Finally, I used Peters waterproofing technique on the nose piece in preparation for painting, and because I could I mocked up how it would look once all is completed (minus the wings, EDF units and landing gear), none of the pieces are permanently fixed together yet, Fat-Shark headset charger is n the equipment bay because I needed weight to keep it flat on the table as the tail is a wee bit heavy right now.

 

[westers47]

Looking great, can't wait to see more.