Hey there! This is my first "legit" scratch build and I hope to get it right so feel free to reply to me if you happen to have any suggestions. However from the title of the post I will be building an ATR-72 out of DTFB mainly along with maybe a few other materials. My goals are to have it fly, have it swappable, and to have a removable nose. It will kinda be a Guinea Pig but different. It will be running on a twin C-Pack from my old Sea Duck. Unfortunatly, I am still in school and will have limited time over the weekend to work on it but I hope it will all be worth it. =D
quorneng
Master member
jakexie6
Perfectly possibly but have you looked at the wing area relative to its likely weight.
These modern turbo prop airliners are powerful, fast, have big area increasing flaps and take off/land from smooth runways. As a result they are not blessed with "big" wings.
https://doc8643.com/aircraft/AT72
Perfectly possibly but have you looked at the wing area relative to its likely weight.
These modern turbo prop airliners are powerful, fast, have big area increasing flaps and take off/land from smooth runways. As a result they are not blessed with "big" wings.
https://doc8643.com/aircraft/AT72
I also saw another ATR 72 online that was RC and it looked great! Not just on the ground but in the air too! That was my main inspiration for this as that one had quite a bit of detail with the fowler flaps and all that. Mine... well more like the spirit of FliteTest with a simple box fuse and all that jazz. Here is the video: https://www.youtube.com/watch?v=Hqw0UhBPGlg Not sure how much power his has compared to the C Pack though. Running two 2200 3s? Geez!
So yesterday was the first day of building. First thing I did was mess with the wing shape to see what I could make.
I just took some measurements from my scale drawing (1/10 scale so I just scale all the measurements by x10)
I just took the inside and outside edge then made up some measurements for the airfoil and soon I had my first design.
The design was really rough with a lot of mistakes but I still made a 1" foam spar and folded it over, and it looked pretty nice! I made the middle section of the wing which was very easy as it was a rectangle. I then joined the two to see what it would look like, and I was pretty happy with it.
I had just come back from laser cutting at my local maker space and I had cut out two power pod mounts from the Guinea Pig (Or the Kraken not quite sure if they're the same) along with two wheel pants and two new powerpods. However before even that I had gone to Hobby Lobby and picked up this 2mm black foam for 98 cents per 18"x12" sheet. I had made a 2in tire in Fusion 360 that I sliced in Autodesk Slicer for 2mm sheets.
(There is masking tape holding everything so that on the drive back all the pieces stayed in order) Laser cut the foam with the design, superglue them together then you get this.
Might as well be the real thing. =D I then 3d printed the hard inner part out of white PLA and then they looked like real wheels from a 747 or something along those lines.
(Fun fact about these wheels, if you put them on a long piece of landing gear wire then look from behind. It's quite easy to imagine a whole 747 landing gear setup.) After this, I finalized the wing design and put some measurements for when I make the final wing.
That was all I got done yesterday, made a lot of progress but still a lot more to go. =D
I just took some measurements from my scale drawing (1/10 scale so I just scale all the measurements by x10)
I just took the inside and outside edge then made up some measurements for the airfoil and soon I had my first design.
The design was really rough with a lot of mistakes but I still made a 1" foam spar and folded it over, and it looked pretty nice! I made the middle section of the wing which was very easy as it was a rectangle. I then joined the two to see what it would look like, and I was pretty happy with it.
I had just come back from laser cutting at my local maker space and I had cut out two power pod mounts from the Guinea Pig (Or the Kraken not quite sure if they're the same) along with two wheel pants and two new powerpods. However before even that I had gone to Hobby Lobby and picked up this 2mm black foam for 98 cents per 18"x12" sheet. I had made a 2in tire in Fusion 360 that I sliced in Autodesk Slicer for 2mm sheets.
(There is masking tape holding everything so that on the drive back all the pieces stayed in order) Laser cut the foam with the design, superglue them together then you get this.
Might as well be the real thing. =D I then 3d printed the hard inner part out of white PLA and then they looked like real wheels from a 747 or something along those lines.
(Fun fact about these wheels, if you put them on a long piece of landing gear wire then look from behind. It's quite easy to imagine a whole 747 landing gear setup.) After this, I finalized the wing design and put some measurements for when I make the final wing.
That was all I got done yesterday, made a lot of progress but still a lot more to go. =D
Thanks! The wheels didn't actually last long on the asphalt runway I was flying off of. The foam ended up ripping om the edges so the foam didn't last very long at least on an asphalt runway. On the other hand, I have had to scrap this project (for now) because at the time one of my escs ended up getting fried and the power that the plane would need was outside of what I had at the time. I do hope to build something like this someday and if it is an ATR then I'm gonna revive this thread.
Vimana89
Legendary member
Nice choice! What you are working with is very similar to the Dash 8 Q400 I'll be building. Mine will be in a smaller size range with 1806(A pack) motors. Mine will have the same challenges, especially since the q400 variant has an extended fuselage with a skinny wing that's 90 percent the length of the fuselage. Not many people doing airliners out of foam board here, but at the moment there's a few in the works so maybe more will try their hand at it. These types of planes will not have the low wing loading of a cargo plane or something with a broader wing, so we will have to keep the weight down with our builds. I may increase the length and wing area a bit from the specs of the actual full size model. It says in the info I found that the real ones vary a bit according the the customer's needs anyway.
quorneng
Master member
With the Q400 in particular you rather have to ignore the size of the fuselage and consider it just as a plane to match the wing area, so it has to be significantly lighter than you might expect. Weight is the key and then it can fly well.
The first time I saw one of the FlyBe planes over head at 2000ft all I could really see against the cloud was the fuselage.
So I simply had to build one!
The first time I saw one of the FlyBe planes over head at 2000ft all I could really see against the cloud was the fuselage.
So I simply had to build one!
Vimana89
Legendary member
That's a perfectly scale looking build, definitely the nicest I have seen. Nice color scheme too. That's depron, right? I've seen a couple of your other depron builds here and there too, including a really nice Hp-115 that I believe is yours. Good stuff👍. I figured wing loading would be the main issue with the Q400, so I plan to build as light as foam board and basic building techniques will allow. How does yours handle?
Vimana89
Legendary member
Sad to hear it didn't go too well. Best of luck with the rebuild when you get around to it. I'm looking forward to it👍
Same here. Always sad when a project just doesn't quite make it to the finish line but I have other things on my hand right now. (150% Edge along with a few other things)
Also, that Q400 looks amazing! One of the best I've ever seen from my research online. Fantastic job.
quorneng
Master member
Vimana89
It is very light. 3mm Depron planks over Depron formers and ribs. It has a balsa spar. Otherwise completely hollow. Motor batteries in each nacelles so the wing is off loaded in flight. No undercarriage so hand launch/belly land to save weight. Low roll rate even though the ailerons are slightly extended. It can even be looped - with care!
Vimana89
Legendary member
Very nice build, great footage, and nice flying too. It appears to be very stable, and the banks look gentle and clean. The loop seems to have taken a bit more effort and precision to pull off than with more aerobatic types of planes, but again, very clean and graceful. Turns out I'm already subscribed to your YouTube channel, just been pretty busy with builds and stuff lately and haven't checked out everything in my feed, so this is the first time I've seen the Q400, but I'm already a big fan of your HP-115. I've got to say, aside from obviously having a lot of experience in the hobby and some impressive designing and building skills with a lot of attention to detail, you also, in my opinion, have great taste in planes
. You've definitely built a couple of my all time favorites and it's cool to see them so scale.I've been in the hobby less than a year and I'm nowhere near that level. I've built a RET slender delta that's somewhat like an HP-115 crossed with a high-mounted pusher prop trainer plane, and strange as it is, it flies very well and is pretty easy to control, even battered and repaired numerous times with tons of glue, and hardly a precision job to begin with. There's pretty much no way to stall this thing in a way that it can't immediately recover from, and landings are almost too easy with the ground effect. It's actually a very flexible and forgiving plane, I can fly it high and fast, low and slow, ridiculous high alpha, etc. A twin engine airliner plane will be a whole new ballgame for me though, and I'll have to learn some things as I go.
I'm still working with dollar tree foam board and mastering the most basic building techniques like A-folds and a few basic curved components. I'll be attempting my Q400 with the skills and techniques that I have at my disposal now, but if it turns out that's not enough and it doesn't seem feasible, I can put the project aside until I have the skillset to take a different approach, whether its rolling foam board like the FT master series, or trying my hand at Depron. Anyways, thanks for sharing your insight and experiences!
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