FT Mini Arrow

[rockyboy]

Another Arrow, ready to take to the skies! (Well, after I add the camera up front and balance her out).



And the bottom. Turned out darker than I expected with the 'gold' vinyl. Might add in some silver here to add visibility for the spectators.


And here's a shot of the power pod before I installed it. Files downloaded from http://www.thingiverse.com/thing:1972543

 

[French]

Last weekend I maidened my newly powered "Mini Arrow-S."The "S" is for sport, clearly. I have a red bottom 2205 2300kv on it with a 30amp esc (5x4x3 V1S). On 3S 1300 mah it cruises at 35-40% throttle. I also flew it FPV for the first time with a little 200mw AIO cam/VTX on a 1S 950 mah. It was so much fun to fly.

I should have my new dvr setup soon and will take some videos next time. I may even try 4S

 

[Micropitt]

Welcome to the addiction! I see you're well on the way to getting your 12-step collection

The need to pull about 1/2 elevator up is a standard wing phenomenon known as "reflex". I was pretty confused about this too, but luckily my first wing flights were at Flite Fest last year where @HildaFlyer was kind enough to show me the ropes.

So you're doing the exact right thing getting the CG where is should be on the plans - that's necessary to keep controllable flight behavior (Center of Pressure and Center of Gravity shouldn't be reversed on these wings - very bad things happen then). The next step is trimming for level flight. Get up to a comfortable height and start bipping the trim button for the elevator control until you get it to stay level without you needing to add elevator manually. This took a whole lot of trim bips on my first flight - maybe 20 or more. Once it stops dropping the nose you can stop here and fly happy, but you'll be missing out on full 'up' elevator control. So on to the next step.

Land quickly before screwing anything up and measure the angle that the elevons are sticking up. We did this by cutting a scrap of foam a couple times till we got a good match on the angle. Then put the radio trim back to center, loosen the control linkage and adjust the elevons so that when the servos are centered, the elevons are at that magic angle. It should be able to fly now with maybe just couple clicks of trim for hands off flight.

And as a wing noob last year, I tell you was amazing how cool it felt once it was setup right.

There is a second option, which is used quiet often with Wings: angle the motor (or motor mount) a tiny bit.

 

[raneous]

Another Arrow, ready to take to the skies! (Well, after I add the camera up front and balance her out).

View attachment 86490
rockyboy: Looks good! I like the carbon fiber vinyl I see you went with the standard Z bends in the pushrods rather than a linkage stopper like you suggested to me. Are you planning on just using sub-trim to work out the reflex and not worrying about the lost throw?

Also while viewing your 3D printed center pod I had an idea. What if the pod was printed with a spar coming off of both sides to go into the wings? This is the weakest link in the airframe and where all 3 of mine have ultimately met there end from the wings tearing off the center pod on the top section. Seems to me that if a spar was added to the printed center pod right where the box spar is or slightly aft of that on the top of the wing you could add small slits in the wing, then put glue in the slits and pop the spar in them as you glue the center pod in. Finish it off with a top coat of glue and wipe the excess for a much strengthened design. I have no experience with or access to a 3D printer or I would try it myself. But just an idea for someone that does.......

"There is a second option, which is used quiet often with Wings: angle the motor (or motor mount) a tiny bit."

Micropitt: It's funny that you suggested putting a tad of thrust angle on the motor. I've read and seen this on the forums and was contemplating doing just that. Then yesterday I watched a video on Youtube of a restored 1943 Northrop flying wing https://youtu.be/2eZjIx_ViOA and those motors DEF have thrust angle! Which made me consider it again. Then about an hour later I read your comment and my mind was made up!
Any suggestions on the amount of thrust angle? I was thinking between 2-3 degrees? I will be accomplishing this by adding the angle to the power pod itself where the firewall is attached.

I'll be building v3.0 soon and will be sure to post pictures and any knowledge gained along the process While I'm on the subject does anyone know what I did that caused my first batch of pictures to post upside down? I'm sure it's something simple I missed being a noob. I was thinking I could invert the files before I posted them to remedy it. (I imported the files directly from my laptop to the post....

 

[rockyboy]

Thanks!

Yeah, I couldn't find the box that had my linkage stoppers so I just went with the classic double z-bend instead. Lesson: clean the shop up between projects, not one cleaning per three projects. :black_eyed: I did get pretty close on the reflex measurement, but I'm sure there will be some adjustments needed after the maiden. If I end up eating up too much of the servo throw with sub-trim I'll either remake the whole control rod, or move to the next hole out on the servo horn.

I do like the idea of incorporating a spar across the fuselage into the wings. 3D printing tends to be pretty week at thin joints, but if a slot was made to incorporate a thin vertical carbon or aluminum spar like NerdNic's speedwings that could be really helpful. I think I'll work on that once this wing is trashed

 

[raneous]

I also just happened to think that it might be beneficial to incorporate the "bumpers" that some of us have been making from foam directly into the 3D printed pod?
If you do come up with a spar version of the center pod or even a "bumper" version please PM me. I would be very interested in compensating you for a handful as I currently don't have access to a printer.

 

[rockyboy]

Sure! I didn't do the modeling directly for this fuselage design, but I'm hoping I can either modify it or work with the original designer to try some of these mods out.

And yeah, I was looking at my fragile little camera perched out front last night and thinking some bumpers are in order too.

 

[Micropitt]

Another Arrow, ready to take to the skies! (Well, after I add the camera up front and balance her out).

"There is a second option, which is used quiet often with Wings: angle the motor (or motor mount) a tiny bit."

Micropitt: It's funny that you suggested putting a tad of thrust angle on the motor. I've read and seen this on the forums and was contemplating doing just that. Then yesterday I watched a video on Youtube of a restored 1943 Northrop flying wing https://youtu.be/2eZjIx_ViOA and those motors DEF have thrust angle! Which made me consider it again. Then about an hour later I read your comment and my mind was made up!
Any suggestions on the amount of thrust angle? I was thinking between 2-3 degrees? I will be accomplishing this by adding the angle to the power pod itself where the firewall is attached.

I'll be building v3.0 soon and will be sure to post pictures and any knowledge gained along the process While I'm on the subject does anyone know what I did that caused my first batch of pictures to post upside down? I'm sure it's something simple I missed being a noob. I was thinking I could invert the files before I posted them to remedy it. (I imported the files directly from my laptop to the post....

Yes, I would start out with 2-3 degree. I had different Wings in the past and it always worked well.
Even Flite Test was experimenting with motor angle ;-)
https://www.flitetest.com/articles/Motor_angles_for_pusher_planes

 

[bandook]

I just maidened my 4s arrow. What flight times do u guys get with a 4s 1300 ? I was expecting 5 minutes, but felt power fade at 4:30 so landed and my pack was at 12.3. lol...too much fun to care, but I will be getting some telemetry for sure. Don't trust a beeper as I like to fly some distance.

Using a 20a ztw ESC, red bottom 2600, 5x4.5bn. This thing rips. Had to mount ESC on top of pod as my first unsuccessful flight had it getting blazing hot. But it's still working, and came down cool today with a lot of full throttle. This is a very inefficient prop so I would guess I'm hitting around 30-35a. Still, feel I should be able to hit 5 min?

 

[ms166]

Hello,

Let me show you my small contribution to the wide FT Arrow custom builds.

I build two versions of the Mini arrow.

The 2016 model was intended to fit a 1300 batterie and be build out of depron 6m.




The 2017 model it is a Blunt Nose type model (wingspan arround 830mm), made from Depron 6mm but with the central part and spares made from EPP, increasing resistance to rough landing. You would be able to fit in a 1300 batterie a flight controler (for INAV) and of course all your FPV equipment.




The Elevon are made out of balsa with a clear laminate cover, the central cover part and the winglet are made out of "alveolar polypropylene"

If ever interested, you can download the files here: http://ifly4u.ch/category/download/

 

[JimCR120]

Both are fine looking planes, especially with those elevons, wow! And that BN too. Yo do excellent work. How do they fly?

 

[ms166]

Both are fine looking planes, especially with those elevons, wow! And that BN too. Yo do excellent work. How do they fly?

The good look is to be credited to the laser cutter at my local FabLab

They are both flying great, and are very easy to fly. I guess I will do a last one, the goal is to reduce the drag to a minimum to fly faster or longer.

 

[CrossedUpChris]

6mm depron mini arrow

I built a mini arrow out of depron covers with packing tape. It's my first one.








I'm running it with a 1950kv funfighter motor with a 6x5.5 prop on 4s. It really motors along!

I've left the electronics bay open as I need the space for the battery. It is held in with a strap.

I have a runcam swift 2 that I might try and set into the leading edge just off centre but I want to fly it a bit more first.

 

[Ch3fk0ch]

Hi,
did someone have a good balanced (flighttime and speed) setup which is available at Hobbyking EU?

I hope u can help me.

Thanks

 

[superhappyfun]

Just tried a 3S battery in my Arrow and the firewall got pushed forward so far that the prop started hitting the back of the plane. I tried thickening the powerpod with tape but it still keeps getting pushed forward. How do I stop this from happening? Any tips/suggestions? Thanks.

 

[raneous]

Use a BBQ skewer. Align the power pod to where it needs to be then punch the sharp end through the center pod in the back. Push it through the power pod and out the other side of the center pod. Then continue to pull it through until you have just a little hanging out where you originally punched through and trim off the excess on the other side. By leaving a little extra you have the ability to easily remove the skewer if you need too. This should hold everything in place for you while flying although any sort of abrupt stop will eventually wear the skewer holes out. Also be conscious of your motor wires while feeding the skewer through.

 

[raneous]

Well here she is, V3.0 (4th build, there was a V1.5). Didn't do much different this time. I got a new toy I've been dying to try (It's in the pictures) so I just threw it together fast. Things I did different from last time was to make my own control horns out of gift card and CF vinyl, then added linkage stoppers. With the X4R I was able to mount it in the bay instead of the center pod. I also soldered some extensions onto my motor wires and put my esc and BVS in the other bay. I was tired of the clutter in the center pod so now it's just wires and battery. Much cleaner. Aside from that pretty straight forward. Not my first choice of paint. I'm more of a black and red carbon fiber kind of guy. But at least one of my crashes on every other build was because I lost orientation. This little sucker moves away from you fast and gets tiny I set out to remedy that with this paint scheme Funny story about the "windscreen/cockpit", It was not there originally but while working on it I hadn't quite let the paint dry enough and it stuck to itself when the hatch was open. Couldn't leave it like that so I put that CF on there to cover it up. Just need to set reflex and throws and it's out to the back field for her maiden. I can't wait to try out my Insta. Trim on the QX 7!!

 

[raneous]

Well the maiden went fairly well. spent 4 800Mah3s packs. 6 landings and 2 crashes. Nothing fancy. Just ran patterns in the back field. I did a couple rolls though and it behaved funny. My last build even on low rates when rolling it spun like it was on a skewer right through the center and at a fairly decent rate. This one, although very stable in flight does a big sluggish barrel roll rather than spinning like the other one. Everything as far as I can think of is pretty much the same. Any suggestions? I want that climb out with 6 spins like the last one!

 

[Hai-Lee]

Simply ensure that you redo the servo out put arms for some differential. (More elevon upwards movement than down).

It will balance out the drag of the elevons and reduce the drag induced yaw component when the elevons are used to roll.

Have fun!

 

[doremonflight]

Thanks for your post. I love it <3.