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FT Flyer - Scratch Build

fliteadmin

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#1


The FT Flyer is a scratch built air frame designed specifically for our 'swappable fuselage' series. The other wings in this series include the Nutball and Delta wing. This episode is a step by step build plan to show you how to make your own modified BluDart, The FT Flyer.

Foam board swappable fuselage scratch build series is setup like this, the Nutball as a beginner, the FT Flyer as the next step up, then the Delta wing for advance flying.

The FT Flyer (BluDart) is a great intermediate scratch build offering all the ease and fun as the Nutball but offering a nice transition into more aerobatics and aerial maneuvers helping you improve your skills and prepare you for the Delta wing.

One of the best part of all of these wing designs is that they are constructed from inexpensive foam board, so if a wreck does happen, you're only out a dollar or two worth of foam.

Scratch building these foam board planes is a fun way to learn more about RC flight, improving your flying and it's a cheap way to explore your creativity in designing your own airplanes as well as a great way to introduce friends into the RC hobby!

The plans for the FT Flyer are available here:
View attachment FT FLYER SWAPPABLE FINAL.pdf


See how to build the swappable fuselage here:
http://flitetest.com/articles/DeltaScratchBuild

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ft flyer - servos.jpg

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ft flyer - battery.jpg

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ft flyer - delta.jpg
 
#2
Nice video! Quick question:

I have the stock bixler engine (rated arround 1800kv) with an 30 amps esc. I would like to use a 6x4 or 5x5 prop with this for your swapable series. Will this work?

No one can help me?
 
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Hal9000

Junior Member
#6
Resposting (with some edits) from Comments section:

I built this over the last couple of weeks and my order of electronics from Hobby King arrived on Tuesday.

There appear to be some errors in the build video regarding measurements. I tried building the undercarriage out of .7 mm wire (14:25 in Delta build video) but it just flops all over the place.

Would you recheck the wire diameter please? It has to be bigger than .7 mm!

Also you show the wheel axles being bent with the voice over saying "an inch and a half" but if you watch carefully (14:36 in Delta build) it is actually .75" I got quite confused here and bent it at 1.5" which looked really odd. Its like the voice over was scripted with out reference to what was going on in the video.

You have in the plans "C.G. IS 20-30% BACK ON CENTER OF WING". Are you able to clarify if this is measured from the front to the back centre of the wing section. My wing is 40cm at the centre line, front to back. So is C.G. then between 8cm and 12cm from the front of the wing front apex?

Still waiting for wind and rain to go away so I can try maidening this. Once I've mastered the basics with this I'll swap in the Delta I've also built. Bring on the fine, almost windless days.
 

colorex

Rotor Riot!
Mentor
#7
Would you recheck the wire diameter please? It has to be bigger than .7 mm!

Its like the voice over was scripted with out reference to what was going on in the video.
Here is where you need to be a "DIY" guy. Use whatever works!

And Flite Test isn't scripted, that's why they make this kind of mistakes!
 

Hal9000

Junior Member
#8
Here is where you need to be a "DIY" guy. Use whatever works!
I am a firm believer in the "do it once, do it right" and "measure twice, cut once" school of thought. Peeves me having to redo something, especially when I am following instructions of experts...

But on the other hand this experience is character building, so I might just add hand launching and catching to my expanding range of RC skills.
 

Frankerad

Junior Member
#9
Resposting (with some edits) from Comments section:

I built this over the last couple of weeks and my order of electronics from Hobby King arrived on Tuesday.

There appear to be some errors in the build video regarding measurements. I tried building the undercarriage out of .7 mm wire (14:25 in Delta build video) but it just flops all over the place.

Would you recheck the wire diameter please? It has to be bigger than .7 mm!

Also you show the wheel axles being bent with the voice over saying "an inch and a half" but if you watch carefully (14:36 in Delta build) it is actually .75" I got quite confused here and bent it at 1.5" which looked really odd. Its like the voice over was scripted with out reference to what was going on in the video.

You have in the plans "C.G. IS 20-30% BACK ON CENTER OF WING". Are you able to clarify if this is measured from the front to the back centre of the wing section. My wing is 40cm at the centre line, front to back. So is C.G. then between 8cm and 12cm from the front of the wing front apex?

Still waiting for wind and rain to go away so I can try maidening this. Once I've mastered the basics with this I'll swap in the Delta I've also built. Bring on the fine, almost windless days.
I hade similar problem when built my FT-flyer. But it is only a help, make a double landing gear instead. But it is diy so you have to rethink and adjust some specs. After all it is free.

I have not flown my FT-flyer but I think you whant the CG 8-12cm from the front of the wing front edge. That is information from RC-groups forum.

I will try to use the swappable fuselage to build a trainer with ailerons but I am missing the servo´s for that now. But that is a separate forum post for that build.
 

Hal9000

Junior Member
#10
Well I think I worked out what size wire Scott was meant to say for the undercarriage.

.07 inch (not .7 mm) seems to be rigid enough, and seems to match what he's using in the video.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#11
It's been too windy to fly for the past week, and I'm waiting impatiently for a delivery from HobbyKing so I can upgrade the Super Cub's electronics. I've got nothing else to work on, so I figured this was a good time to do a little scratch-building.

I made a pair of NutBalls with my son a few months ago and we got NutBall #1 set up to fly, but quite honestly I didn't care for how it flew. Based on how everybody raves about the NutBall it was probably my fault, possibly not the correct angle for the motor, maybe underpowered, could be the CoG. It flew, just not as good as I'd have liked. It crashed nose-first like a pro though. I'm surprised that the motor still works!

Yesterday it was time to make use of the fuselage made for NutBall #2. Off to the Dollar Store for some more foam so I could make the FT Flyer! A couple hours yesterday and today, some canibalizing of the parts from NutBall #1, and it's ready to go! (Other than needing some color)

It was a pretty easy build, and the plans were followed about 97%. I'm upgrading from the 500mA 2S used on the NutBall to a 1300 mA 3S, as it puts the CoG dead-on. Plus it really gives some extra kick, which could be either fun or dangerous.

2012-09-23_19-35-59_713.jpg

Pictured along with the FT Flyer is the airframe for NutBall #2, which hasn't seen any flight-time yet. I said "YET", as one day I'll get around to playing with it again.

2012-09-23_19-36-37_905.jpg
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#13
Anybody who's built the FT Flyer, what did you end up with for a CoG? I started with the 8-12 cm distance listed, but the plane REALLY didn't like that and took a dive for the ground. No damage to the plane, but I ended up losing the only o-ring I had for the prop saver. After a little more research I found another statement stating a CoG of about 5-1/2 to 5-3/4", approximately 1" farther back. I can shift the CoG there easily by moving the battery. After I get another o-ring I'll give it a shot, unless anybody has other suggestions for the CoG.

Also, I'm using the HexTronik 24 gram brushless outrunner, 1300kv with GWS EP props, 8" x 4.3 pitch according to the HK website. These were originally for the NutBall, using a 500mAh 2S. For the FT Flyer I wanted more power so I switched to a 1300mAh 3S, and it's got plenty of juice now by comparison. But am I over-powering it, using a bad motor/prop/battery combination? I'm still learning this as I go along, and quite honestly this aspect of it all confuses the crap out of me.
 

colorex

Rotor Riot!
Mentor
#14
Also, I'm using the HexTronik 24 gram brushless outrunner, 1300kv with GWS EP props, 8" x 4.3 pitch according to the HK website. These were originally for the NutBall, using a 500mAh 2S. For the FT Flyer I wanted more power so I switched to a 1300mAh 3S, and it's got plenty of juice now by comparison. But am I over-powering it, using a bad motor/prop/battery combination? I'm still learning this as I go along, and quite honestly this aspect of it all confuses the crap out of me.
The motor you are using (HXT 24 gram 1300kv) is a perfect match for the 3 cell battery - as long as the 1300mAh size isn't too heavy. The prop you are using is a bit steeper than the recommended prop, this might be fine, but just check the motor and the ESC to make sure they are not heating too much (warm, but shouldn't burn your fingers).
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#15
The wind finally cooperated with us today so the boy and I got a chance to take the FT Flyer out for it's maiden flight. The first couple attempts found it still waaaay too nose heavy. Once I moved the battery back as far as possible it became airborne fairly easily, although it seemed like it was still a little nose-heavy (I was giving it a lot of up-elevator).

The entire flight was at half-throttle or less, with 3-5 mph winds. The park we were in isn't very big, so I wasn't going to really go too crazy with it or really open it up.

Based on the video evidence, does it appear to be balanced, nose-heavy, or tail heavy?

 
#16
Well I pick up a Hamilton's worth of foam and last night in about 3 hours I made the delta, nutball, flyer, and the sidewinder missile!

Flew the swappables this morning in 15mph winds and I love them all. It's my 2nd nutball but ive had 12 snowballs but my first delta dart and delta w/kf foil and of this size.

My fuse has the blue wonder on 20a esc and ar6100 rx. 2s and 3s 500mah lipos. No landing gear. I didn't use paint, instead I used colored packing tape. Works great.

Servos are just random extras u had between 7 and 15 grams in weight.

I love the build techniques and I'm amazed that they come out light enough with the paper on! This makes the. Very strong! I flew the delta into the house wide open and it tumbled to the ground with damage of any kind! Just a crease in one wing. The delta isn't all that fast but flies well and rolls crazy. It'll do flat spins and waterfalls. It's a little heavy on the wing but the 3s gives it way more power than It needs!

The dart is great. Very slow but will do aerobatics just like the nutball but flies slower and more stable, IMHO.

I've got to get servos for the rocket but I know it will fly well.

Next I'm going to do the bloody wonder and fogey. After that I'm going to design a 3D swappable and a seaplane if noone beats me to them!

Thanks for these great budget fliers!!
 
#17
The wind finally cooperated with us today so the boy and I got a chance to take the FT Flyer out for it's maiden flight. The first couple attempts found it still waaaay too nose heavy. Once I moved the battery back as far as possible it became airborne fairly easily, although it seemed like it was still a little nose-heavy (I was giving it a lot of up-elevator).

The entire flight was at half-throttle or less, with 3-5 mph winds. The park we were in isn't very big, so I wasn't going to really go too crazy with it or really open it up.

Based on the video evidence, does it appear to be balanced, nose-heavy, or tail heavy?

Looks fine if not a bit tail heavy sense it looked like it was flying in a high alpha attitude in the beginning and not gaining altitude but you said it took holding up elevator to fly so idk.

If your thrust line is zero or with a couple degrees of down, and the wing is level with the horizontal stab then it should fly level at half throttle with no elevator trim if its balanced. The elevator should be inline/level with the horizontal stabilizer.