Building a WEIRD RC Plane... Will it Fly?

[@michaelrechtin]

To try everything Brilliant has to offer-free-for a full 30 days, visit brilliant.org/MichaelRechtin . You’ll also get 20% off an annual premium subscription.

[@Trending_Clips-10k]

I just custom made a RC jet. How do u calculate were the cg should be?

[@Gabebuildsthings1234]

@@Trending_Clips-10k 25% back form the leading edge, if the wings are swept from the smaller outer end of the wing, go 25% back from there and then draw a line across and then that’s where CG is

[@keaganmichel1875]

Your problem is that it’s a V tail that is quite complicated rather try a normal tail @michaelrechtin

[@eriknulty6392]

Try to build a Q200 QUICKIE for your next plane. VERY ODD BUT COOL AIRPLANE.

[@ZapTeam]

@@Gabebuildsthings1234or go crazy and make it neutral

[@NicholasRehm]

Little did he know.... the cheese color was a sign of the many holes to come. RIP, swiss cheese plane

[@alienbeef0421]

lmao

[@prothomasgaming]

"If there's a hole, there's a goal." Wisest words ever said, now said by me 17:50pm 31/05/2024.

[@sicks6six]

ouch

[@bbbo85]

I mean it fits the swiss cheese model

[@sathyarajesh9018]

nicholas what

[@joshwalsh4890]

V tail was too small, didn't have enough authority to keep the plane straight.

[@NiteAtTheFort]

doubt that's the issue since they were as large as the old wings

[@newmonengineering]

Actually part of the problem is rough air from the rear motor. If he made the fusalage longer and then pushed the tail further away from the blades is would help a ton. Wider tail surfaces might help a bit also but not so much longer. I think the largest issue is they are too close to the front of the propeller. Many pusher airplanes are more rear wing and canard style. But with this style it needs a bit smoother air and longer fusalage to give it a longer lever movement

[@jaketus]

Combined with the camera sticking out causing huge drag on one side, I'd say that's pretty much the cause.

[@toolbaggers]

V's too small for short tail length.

[@toolbaggers]

@@newmonengineering The tail doesn't see the rough wind of the rear motor because this plane doesn't fly backwards.

[@LanceKnott]

Please don't give up.

[@frankytank108]

Don't let go, never give up it's such a wonderful life

[@Xailow]

Looks like your v-tail is a bit small for the vehicle. And with such a high wing loading, you'll probably need a faster launch speed to get going properly.

[@wolfganghorn7492]

I once tried building something of similar proportions, and it definetly needed more surface area in the rear. maybe even add a third smaller fin on the bottem for more yaw stability.

[@Martillo.1.11]

I do agree! I'm not an engineer but I mess around a lot with foam thingies, v tails are weird, he definitely needs a larger surface!

[@PabloYaggi]

I would love the video about the foam cutter.

[@John-z7b9y]

That would be very cool..

[@deepset]

My eyes got wide and ears perked up when I heard the words 'CNC foam cutter'

[@danyo41]

Bro just casually said "...on my CNC foam cutter" like it was nothing 😂. I'm more interested in that than the plane now.

[@Fireflyepic]

The sheer amount of revisions you decided to pack into one video has earned my like. Most youtubers would split this into at least 4 parts. Mad respect.

[@romanwalchli8550]

Too heavy (should be around 300g to max. 700g, wings too small, ailerons too small, V angle too flat (should be 90 degrees) and a flight controller is not necessary. The motors should rotate in the opposite direction and the CG must be correct. Have fun on your second attempt...

[@TFlight77]

Everything said above. A flight controller is an aid it still needs a correctly weighted and balanced plane to fly or it just masks the problems.

[@fliteanalysis4927]

How will you, (as a hobby guy) calculate the area required for control surface ? Any thumb rule. Pls let me know

[@wardy89]

Yea that’s a pretty good summery I recon. A couple of additional notes, the v tail looks to small for the aircraft which could be the source of some of your control issues, and I wonder if there is some funk aerodynamics fighting each other a combination of the prop at the front and the pusher at the back very close to the v tail. Also worth slimming down that fuselage a fair bit too.

[@romanwalchli8550]

@@fliteanalysis4927 Start with building plans that you modify slightly. Orientate yourself on the weight and dimensions of existing model aircraft. Once you have enough experience, build your own models. And light models always fly better than heavier ones.

[@gperpetuo]

V tail angle is a combination of the needed horizontal and vertical volumes. There are formulas to help calculate the needed volumes depending on the type of plane. Then there are formulas to help with the conversion from conventional tail to V-tail... you can end up either with 100-110deg or the other way around at 80deg... Having 2 rotating masses at each end sure will increase drastically the inertia of the plane making the tail volumes calculation even more critical. Plus everything else already mentioned

[@beforebefore]

I would suggest dual motor control channels, and start with the pusher at 50-60% of the puller... then you can play with it once it flies. I would also stay away from running too many experimental ideas in the same plane, at the same time. Use a traditional set of tail feathers... and keep the larger wing. I would also make sure the props are big enough, they seem a little small-ish.

[@BeefIngot]

Why would you do that with the push puller? Sounds like a bit of rockets fallacy

[@shadmansudipto7287]

​The two props aren't stabilizing each other but creating the yaw that he notices. Although this won't fix it. Maybe rudder trim needed but he doesn't have a rudder. ​@@BeefIngot

[@BeefIngot]

@@shadmansudipto7287 Not sure you got what I was saying. Im talking about power.

[@cambridgemart2075]

It would also help him determine if the two thrust lines are correctly oriented which is crucial with a pusher puller arrangement.

[@billyvray]

Foam cutter vid! Yes. I have stopped my current build of one to see your latest. Cmon. Get with it. Lol

[@noanyobiseniss7462]

You need to build a scale air tunnel.

[@xjet]

This is exactly what happens when you paint a model the wrong color. You should have consulted my wife, she'd have put you right 🙂

[@sylvainponchelet4188]

a real pleasure to find you here, a big hello from France and lots of thanks for your fight against the absurdity of certain regulations

[@xjet]

@@sylvainponchelet4188 Thank you for the kind words. I shall continue the fight!

[@247printing]

Content EXACTLY how I love it: Interesting, concise, great narrative, great filming and editing!

[@ChrisMuncy]

Michael, I am glad that you show all of the effort, more bad than good this time, of trying to make this fly. But I think you need to get back to basics. Take a look at the Cessna Skymaster. Traditional high wing with a pusher puller configuration that might make it easier to get the CG in the sweet spot which seems to be the biggest issue here. Got the popcorn ready for the next video!

[@CarsonMcDonald-wf4je]

Hey this is an awesome idea and I have some solutions to your problems. 1 build it a bit bigger 2 get steel cubes for nose weight if needed even. E-flite does this. 3 do put landing gear on it 4 possibly bigger propellers 5 try having a mode where you can fly it just as a puller or pusher to get it up in the air at a decent altitude so then you could test the dual propulsion. 6 you could have possibly plugged them in wrong (I don't imagine you did) but this would mean both are spinning in the same direction maybe creating that yaw issue. To solve this just flip the red and black wires in the back. Good Luck!

[@krzychurocketman]

It's hard to imagine that the control problems in the roll axis are caused by the motor arrangement, so there has to be different explenation. Likely your plane has very high wing loading and requires a fair bit of speed to stay aloft. You are using quad props with quite low pitch so there is a lot of static thrust but no thrust at speed, thus your plane never achieves speed when it's controlable. Moreover the v-tail arrangement has adverse roll coupling which might make the problem worse.

[@Al_Ares]

You could try rebuilding the Do-335 and start testing from there since that model was stable enough to fly, also which you could find the reason why your model kept crashing. Even if this model wasn't a huge success, it was a huge leap in learning from experience and it was incredibly fun to watch. I really hope you bring up this project sometime in the future and I wish you a very, very good day!

[@fabiom7078]

Make sure the thrust angles are correct and the propellers are both facing the right way (the thicker leading edge facing the front of the plane), it looked like in the beginning the rear prop was on backwards which could lead to some unwanted roll. And keep trying, this is a cool project :)

[@LalitSingh-ul6ii]

You have made a very good plan which crashed several times but you still made it again and again and tried to fly your plane. Crashing a plane and then rebuilding it is a part of this hobby which is a lot of fun. Your videos are very well made.

[@adcrane]

Keep it up. You are on to something and closer to success than you think. Suggestions: 1/ Get it balanced for inherent flight stability first. Glide test it on a slope without props on it and without flight stabiliser on. 2/ Once it’s stable in glide, put a prop on the front and try it off the slope powered, without flight controller, then with. 3/ Once stable, add the rear prop, without, then with FC. Can’t wait to see the project evolve.

[@th0mas348]

I know it sounds like a silly question but were you absolutely certain that both motors had props that span the correct way/ produced thrust in the same direction and rotation. Hope this helps 👍 great vid

[@nacorti]

Your build setup is super impressive! I'd recommend tackling one unknown at a time, which would mean 1) Build a glider to test your wing loading, tailplane authority, etc 2) Add 1 motor to the glider, get the simple RC flight working correctly *then* 3) Add the 2nd motor and live your Do-335 dreams It'll be slightly slower going but I promise it'll be less frustrating! Great work, subscribed!

[@prothomasgaming]

Usually having the center of lift in front of the center of mass causes the plane to be very unstable, kinda like the same reason why rockets have the fins all the way back, so there is 0 stability problems caused from the center of lift being in front of the center of mass.

[@thanasisrks4944]

Perhaps you could move the motor back and connect it with the propeller using a long axis

[@TimJC513]

In addition to the comments on V tail size, I would also recommend setting up the tail surface controls differently. You have the control rods connected to the bottom of the surface. This is bad, because it places up control rods in compression (allowing them to flex and bend) when applying up elevator, which is WAY more important than down elevator. By attaching the control rods to the top of the surface you now have them in tension when adding up elevator. There are ways to support control rods mid span to minimize flex in compression, but it may still compromise control authority.

[@loodwich]

The problem with the Do 335 was the lateral and longitudinal control, for that reason the plane was with the tail in the crux form † , so I will make several recommendations: 1) Use the second wings, the larger wins to reduce the load of the plane. 2) Try to have the most uniform fuselaje in the plane, the step in form of the pusher motor kill all the power. 3) Make an X tail to have real control of the plane Keep trying, is very interesting.

[@TK421-53]

The pusher engine was just aft of the wing, which also changes the CG.

[@KF99]

I don’t really like V-tail layout. Try a conventional one, it should give much better stability. Or just add a ventral fin to make a Y-tail. I had similar problem with one of my early planes. Does it have wings of EPP? In terms of reinforcement and making smoother skin - try to cover it with fiberglass using elastic epoxy resin - I had recently discovered and tested this brilliant technique. P.S. could you upload CAD model for us to edit?

[@AdamWebb1982]

As soon as i saw the first design i thought the wings were too far forward, if you took the rear motor off it would have been fine like that. The plane probably needs a bigger conventional tail, and the rear fuselage needs to taper down to the prop more. These planes were hard to balance in real life as well and had 1000s of hours put into them so dont give up!

[@sumynona.01]

Wouldnt having 2 propellers in a line mean the back propeller has to go through the turbulent air of the first?

[@nork7045]

en.wikipedia.org/wiki/Contra-rotating_propellers Thats good for efficiency

[@sumynona.01]

@@nork7045 dont all of those have both propellers at the front of the plane? what im saying is having 2 propellers in front of each other with such a massive gap means that theres enough space to create turbulence, which would probably reduce efficiency, right?

[@nork7045]

@@sumynona.01 well, it probably isn't as efficient as an actual contra prop but the 2nd stage of contra props get turbulent flow too. You can only get laminar air flow with very specific conditions and geometries. For that matter all pusher planes' props get turbulent air from the body and wings

[@sumynona.01]

@@nork7045 yeah good point

[@crackedemerald4930]

they also have to go through the accelerated air

[@TheDaniel366Cobra]

A video on your foam cutter would be interesting. I made one myself recently and one of the problems was maintaining constant hotwire tension when cutting wings with large sweep or taper. I used a keycard reel to store excess wire and tension it (rolled ribbon springs apply a nearly constant force and have good extension), glass beads as endpoint "eyelets" to pass the hotwire, and a brass sliding brush to deliver current regardless of the wire's unwinding/winding against the reel.

[@Gabebuildsthings1234]

I made one a few years ago, but it had a flat horizontal stabilizer with two vertical stabilizers on each end and actually flew pretty good. It is super heavy so it would drop out of the sky if you didn’t have throttle.

[@BotondCsoka]

Amazing video! Can you make a video about the electronics, and the detailed mehanics of building an rc plane?

[@gyrogearloose1345]

What you are missing Michael - aeronautical design expertise! Proficiency in setting up model aeroplanes! Caution with digital flight controls with untested flying machine! And a few others! On the hand - kudos for your manufacturing skills! Wishing for good fortune!

[@tinman7551]

Wonderful video as always 🥰😍 do you mind me asking what type of glue you were using in the build ?

[@Kyle_0701]

Yes foam cutter video please. I think most of your subscribers wouldn't say no to that.

[@Jojo43O9]

The foam cutter is awesome I NEED a video on it!!

[@tenns]

i think elevons are located on the wings, and tailerons on the tail, but only laid flat. What you built is a V-tail which is neither i think.

[@MCsCreations]

Definitely do not give up, Michael! Keep trying!!! There are lots of airplanes you could use for reference for the geometry... So, please, keep trying! 😃 Stay safe there with your family! 🖖😊

[@eanders7992]

If I remember correctly the original Dornier 355 had big rudder and elevators, but also the underneath rudder not only protected the rear prop but added more stability that was needed for safer flight. I don't think you have enough surface area on the rear to keep the plane stable with the added rear prop.

[@pantern2]

I may be way off here, but wouldn't the counter rotating propellers at the front and back work towards getting the plane into a flat spin, which the aerodynamics of the v-tail would translate into a barrel roll?

[@tomscott1159]

Tail: Add vertical stabilizer, pointed down with rudder and very robust actuation system. Replace V with larger horizontal surface with elevators. Insure proper balance! Increase torsional stiffness of all structures.

[@therealjamescobb]

The wire foam cutter looks great. It almost seems like its part of the CNC? Thats awesome!

[@antoniskaloterakis7996]

I am not experienced but what I feel is that the pushing from the back motor interferes with the rudder and elevators. You could possibly put a weaker motor behind or instead of having the servos move the rudder and the elevator make them tilt the angle of the rear motor. Like what jets are doing. I know it will end up as a totally different plane but that was my thought.

[@whiffingherbs]

@michaelrechtin its the v-tail. it lowers pitch and roll and yaw stability because its angled. the fact its angled makes it so when you yaw you roll and thats why it spins when you try to yaw it. the ardupilot tries to counteract that and it does but that means you have less roll authority. this creates a feedback loop that spins the plane. another part of the feedback look is that its very lowly angled which means you have almost all rudder control going into roll and barley any yaw stability. just use a standard tail instead.

[@voltNik_channel]

Чтобы такое летало нужно чтобы задний винт давал меньше тяги чем передний. На вашем видео отчетливо видно что жопа самолета обгоняет передок, что дает нестабильность полета. Поставьте 50% газа на задний мотор

[@ArvinDomingo]

Please don't give up!.. I saw another Dornier Do 335 and I noticed that both front and rear props are spinning in the same direction, maybe you should try that configuration?.

[@dfgaJK]

6:50 I don't think that that amount of control rod deflection is good for control 🤣

[@billjonesnation]

Your workshop is awesome.

[@Erowens98]

I believe part of your problem is that the fuselage is not rigid enough. The counteracting torque of the two motors is causing the fuselage to twist, so when the plane is trying to pitch up for example, it is also being yawed. Aside from designing the fuselage with an intentional pre-twist so thats its straight under flight conditions (which would require an estimation of the twist you're getting), perhaps a wider rectangular profile spar in the fuselage will improve the torsional rigidity.

[@OnePilot12222]

What a great video! It was so awesome to see a project like this. 😃 Some ideas: From what other comments have said, I reckon it may be a good idea to enlarge the V-Tail section, maybe you could also give the ailerons a larger surface area? Also, the idea you suggested about scaling the model up is great! I would love to see a bigger model. Perhaps with landing gear?

[@MarcStollmeyer]

There will be a lot of yaw effect from this prop configuration. You definitely need a large vertical stabilizer, and maybe even cg even farther forward. I’d also think about adding a small tilt to the mounting of the motors to offset prop effects. Maybe fly it manually first because you just don’t have enough time to tune ardupilot and that could be contributing to the crashes.

[@mrbushman2267]

Maybe not the primary cause, but i'm a bit skeptic about the camera you have mounted straight out on the left side of the fuselage. I had a similar solution one time with a small keyring camera, and it acted like a rudder. Made the plane wingstall when i turned to the left. Before i mounted the camera, it flew perfect. Aerodynamics is hard.

[@ConsultingjoeOnline]

The back motor needs too be in the middle with a carbon fiber shaft to the tail. Try try again. Great video!

[@spock81]

4:35 Those would be "ruddervators"

[@raymondelder5004]

Good choice on the speedybee flight controller! I have a wing mini also after some failed trials with a ZOHD kopilot (unfortunately my plane flew away) But the software compatibility with these is great. OSD rocks!

[@franciscograndi]

Idk if anyone has mentioned it already. But I'd love to see if smoothing the surfaces of the wings could help a bit as well. Filling the little gaps and having a smooth surface could prevent an early stall Don't give up!

[@LBJHJP50]

The opposing spinning propellers do counteract roll but are additive in yaw. Imagine a hoverboard spinning on the spot

[@playerJohYT]

This. The gyroscopic effects of the props lead to this yawing effect. Similar to prop walk on boats but twice. And without a bigger, vertical rudder there is not enough yaw authority

[@Skinflaps_Meatslapper]

You're both incorrect. In an aircraft like this, the P-factor (the combination of four different forces all combining to create a yawing moment) is balanced and counteracted between the two props. This is no different than a contrarotating arrangement seen on some Griffon powered warbirds which have no P-factor to speak of, they're just separated on either end of the aircraft rather than being stacked together. The problem here is that unlike a Griffon powered warbird, the two props are not designed for this and are not producing equal amounts of thrust, so the benefit from having contrarotating props eliminating P-factor is not going to be realized as apparently. One of them is in clear air spinning slower and developing ideal thrust, the other is in dirty accelerated air and isn't able to develop as much. Thus, you have a discrepancy between the two props, leading to a yawing moment. The V-tail is compounding this problem, and with a conventional tail arrangement of adequate authority, the P-factor discrepancy would be a non-issue.

[@lechatdubanc4308]

​@@Skinflaps_Meatslapperthere is actually a major difference with Griffon engines. On the Griffon, both propellers are attached to the "same place". Here, one is attached facing front and the other facing back. In this configuration, if you look closely to gyroscopic precession, they are actually piling up. If you look each propeller from the motor's mounting holes, they are both spinning CCW. To not have this problem, the rear motor would have needed to be mounted the other way i.e. facing front but it's not possible 😉

[@LBJHJP50]

@@Skinflaps_Meatslapper i like how you said we were wrong then proceeded to very clearly explain why we are correct...

[@Skinflaps_Meatslapper]

@@LBJHJP50 If you actually understood and followed along with anything of what I said, then you'd realize just how contradictory your statement is...but you don't, and you're getting completely separate things mixed up together in addition to not understanding the aerodynamics and physics of this in the first place. When you combine your very limited understanding along with your smug attitude, it doesn't really matter what I say after this, you're going to think you're right anyway. I have no interest in explaining what you're not understanding, you won't doing anything worthwhile with it anyway, so enjoy wallowing in that delicious Dunning-Kruger effect with your newfound buddies.

[@Jbzy3000]

Just got into 3d printing and I would love to see the foam cutter video. Tried a fully 3d printed machine and it ended badly. Back to cars and boats for me. This video got you a new subscriber. Looking forward to revision.

[@peteroman4297]

I think you had way too heavy of a battery plus you have to make sure that the CG is absolutely correct. Next the control surfaces need to be a bit larger and longer plus stick with a traditional tail wing set up first to see if it’ll maintain flight. For testing new aircraft you should always start off with full control surfaces like ailerons,elevators, and rudder (stabilizer) but as I mentioned before CG is pinnacle.🤷🏻‍♂️💯👍

[@AJHewson1]

Fun project 😊 add some more vertical stability area at the back. A sub-fin would help here. Basically turn it into a Y tail. The dornier had this to help with the issues you’re experiencing. Never give up and never let the learning stop 😊

[@michaellew1297]

The wings are possibly not stiff enough in tortion so that the ailerons can cause an opposite twist. Cover them with something like brown paper or fibreglass.

[@valeriobertucci6159]

I am quite ignorant in these things, but I have seen what for me is a problem: the profile of the wings and/or their rigidity. With the first couple the plane wobbles everywhere possible. Then you tried a few solutions: bigger wings and their position. The plane immediately tends to lower its nose, then in the latest accidents the wings snapped. So I thought that the air at the ends of the wings near the ailerons was generating too much lift there, and/or the wings were too stiff. Maybe due to the position of the carbon bars

[@antonnym214]

Do-over is a good thing. Larger tail surfaces, move the wings back, she'll BE right, instead of YAW right.

[@HopefullyAnAircraft]

That camera right above the wing was probably spoiling the lift on the left wing for that crash before you rebuilt the wings to be larger

[@HopefullyAnAircraft]

You can see in the video that it rolls hard to the left, because the right wing has more lift. Also, making sure that your wings are as smooth as can be, especially on the leading edge and the top is important

[@heydeohgee]

I think that due to the turbulence and relative air speed the pusher rotor was too biased. I think for proper performance the puller rotor needs more power than the pusher. Thus the yaw instability.

[@willowehrich6207]

Do the same design again but with a larger conventional tail!

[@ThreenaddiesRexMegistus]

The Pfeil flys quite well in RC form. You haven’t got enough tail surface authority with the V-tail, which was even problematic in full size aircraft when it was used, and it introduces further complications to control. Also looks like way too much weight for the wing area. Otherwise it’s a really nice build. The foam cutter is fantastic! 👍🏻

[@macrumpton]

I wonder if the tail is supposed to act as a stator to untwist the airstream coming from the front prop. In that case the v tail is worse for that purpose. I would try it with just the forward motor just to make sure the airframe is viable, then try it with just the rear motor to isolate any problems.

[@jamesbernard8072]

The real life do 335 had a mid rear engine and had a driveshaft going to the tail

[@TechKnowCSS]

THAT IS WHAT I HAD POSTED BUT EXPLAINED HOW TO DO IT.

[@ardaricus1566]

Also the plane just has bad yaw authority because of the rotational inertia

[@ЗінаїдаПетрівна-в1ф]

Please don't give up. May I ask a stupid question : does your motors have different spin direction?

[@flixd2513]

i got an idea, what if u made some co2 cartridge rockets? im guessing theyre to obig and heavy for rc planes but the concept would be really good. I like the idea and maybe it would be on some bigger planes?

[@hamsterwolf]

I know nothing about building planes but i got 2 ideas first maybe the props should be shaft driven so you can confirm both are spinning at the exact s and speed. Or maybe mix the throttle or a more aggressive blade pitch so the front motor produces slightly more thrust. In 4 wheel drive in cars a more front bias creates stability a rear bias makes the car more likely to oversteer making the car more drifty. Maybe the same applies here.

[@Demongornot]

For the CG being too far back, one easy fix would be to move the rear motor further forward and use a shaft between it and the prop, bearing are definitely required for this tho.

[@anon_y_mousse]

I suspect that it's a size issue. The plane is at too small of a scale and the air doesn't flow from back to front the right way to interact with both propellers correctly and thus it's causing instability and lift problems. I would double the size and try again and see if it flies any better.

[@jakeknapke1506]

You designed this plane exactly how I would have. V tail looks a bit too small, but other than that I’m stumped on why this thing couldn’t get going

[@eladelbaz5284]

Hi. Very nice video! Check the directions of the gyro. I once glued a gyro on a plan in the opposite direction, and the fixing was extremely wrong. It's handled like a negative stability, even when the CG was perfect.

[@basgerritsen9669]

Michael, have you some some simple checks like calculating the tail volumes for this design? The v tails do look a bit small, maybe it would be interesting to go back and check this. maybe even model the plane in XFLR5 or flz vortex and see what tweaks could make it perform better. Which airfoils did you use for the main wing and stabilizer by the way?

[@keatonhare7691]

This seems like it is definitely a CG/aero issue. As others have said, make sure to keep your control surfaces and tail large and your cg where it should be (25% behind leading edge or so) I also recommend going nose-heavy rather than tail-heavy to start. Also, for a design like this, a bungie or Hi-start launch will save you a lot of headache

[@trafton00]

Tail definitely too small

[@trondaustad8617]

Keep on testing it mr. Cool video 😊

[@Hebesphenomegacorona]

I reckon the problem is poor yaw stability. When the plane starts to yaw this causes unwanted induced roll. Additionally when the flight controller tires to correct the yaw you lose some of your pitch authority due to the use of a V-tail. Making the tail bigger or not using a V-tail would probably help.

[@gageseaux8529]

Even though the two propellers rotating in different directions would negate the roll effect, would they not produce a yaw reaction due to differential prop walk?

[@Juicy-maxy]

You should try making the fuselage longer hand have higher wing ratio for test flights and try to make it slightly nose heavy

[@nanomiterctech423]

Ahhh just for your info , I made one like 4 yrs ago , just that it was like a cessna , top mounted wing and one prop was on front of wing and one on the back of wing I balanced the thrust angle and it worked in 1st go 🤘 Just want to say that the concept will definately work without any problem .

[@thebikeracer]

Def do a video on the foam cutter. Interested in the software you are using and that process too!

[@A.Lifecraft]

Putting the rear motor further forward and mounting the prop to a shaft might help. Also the puller-prop will interfere much more with the flow around the fuselage and wings than the pusher prop does, so maybe testing the plane with the puller motor only and doing proper aileron-trim would be advisable.

Maybe the tendency to roll and yaw has something to do with motors torque. Maybe it's the aerodynamic influence of the camera. Test it with one motor at a time until you get a stable flight, then test it with both together to see if anything changes.

[@Heimdoe558]

1. The Fuselage is to long 2. Weight distribution at the ends of the fuselage leads to an inertia that can not be outweighed by the relatively small V-rudder size. 3. Vibration of this setup is adding turbulence to the V-rudder.

[@jhejhobbies5850]

I feel like I need to build a much simpler version of this with foam board to prove that it will work. There are a lot of issues with your build, the glaring thing that got me was how you seemed to thing CG wasn't that big of deal. CG was probably your biggest problem with this plane. The best way to find the proper CG would be to hold it upside down and test is that way. The design itself was good, that plane will fly, maybe need a little more experience and don't rely on the flight controller to correct major CG problems.

[@dbtest117]

Calculate the weight and adjust where you put the wings when you design the fuselage. Moving the wing backwards instead of adding weight.

[@dbtest117]

Also are you sure not one of the propellers just act as a break. If they rotate at the same speed it may not actually help. They are not close to each other so I doubt you get the benefits that usually counter rotating propellers give. It also looks like it’s too heavy, not just unbalanced. Further are your motors angled as they should, I suspect the rear engine is just making things worse if you have mounted them straight. You might need to double angle of thrust compared to how it’s normally setup. Depends on the engine rotation whether you should angle front motor left or right. Normally a one should also angle them a bit downward. However with a rear engine messing with all this I can’t say for sure how you need to set it up. Begin with disabling the rear engine and make engine mounts for the front motor angled as appropriate. When you get it to fly with just the front motor running start experimenting with the rear motor. PLA is heavy. Don’t print parts that use any unnecessary material. If you can get away with one wall don’t print more. If you can design a model you can print in vase mode. Do vase mode. I have not yet tested lw-pla but I have a few rolls waiting for some prints.

[@netroy]

This could be a good opportunity to collaborate with someone who's also excited about RC exploration.

[@danielskoog5565]

Epic build & perseverance! Maybe some larger control surfaces/more throw would help, and larger tail as well. A video on the 4 axis foam cutter would be awesome!

[@nathancooley8459]

To be elevons or tailerons the tail surfaces would have to induce roll. The surfaces on a v-tail only do yaw and pitch, which makes them ruddervators. Pedantics out of the way, this is a pretty awesome build dude!

[@CZD31095]

for the beginning of the video i was like "OH ITS THE DORNIER DO-335!!!" lol

[@peter360adventures9]

Awesome work and never give up.

[@DrewWithington]

The reason they went down this design route with the Dornier Do 335 was to have the power of a twin engine plane with the frontal area of a single engine plane. So it should go faster. Which it did.

[@kmom777]

Maybe a 3d printed rod going thru the whole wing from end to end acting like a construction steel bar for support.

[@stejer211]

RC builders proverb: an airplane with center of gravity too far forward flies poorly, an airplane with center of gravity too far aft doesn't fly at all. But you know that by now ;) In addition to the previous tips from the commenters, an airplane in this configuration is about the worst if you have little to no flying experience. A high-wing monoplane is much more auto-stable, have a look at the Cessna 336 and 337.

[@zhiqiandu3110]

Number one big issue is the sharp leading edge of the wing. It stalls at even slightest AoA. Combined with a weak V tail and huge moment of inertia from tandem motors, it is a guaranteed failure.

[@MichaelMillage]

Try a little laminate on your foam parts, it doesn't add that much weight and makes the foam real strong. Twisted Hobby, minimum rc and aloft hobbies are good sources for iron on clear laminate. It comes in thicknesses of 1 micron to 6 mm thick. I build a lot of foam airplanes for indoor and outdoor use , I have found that the laminate works very well.