Hey guys. I'm beginning with aeromodelism, and I've been studying the possibility of making this plane (F-22) in a future.
Pic related is a diagram of the servos that I'll need (not even including landing gear and twin fans).
How could I handle this huge amount of servos?
Retard.
>>984153
To fly. Actually this guy inspired me:
https://www.youtube.com/watch?v=-8F27CC78X8
>>984136
If I was doing this I'd want to go all on with a custom flight controller, probably based on one of those Arduino flight shield things, dunno if it can actually support any more servos or at a fast enough rate.
I'd want it to be fly by wire where I make simple inputs with the RV co troller and the computer automatically mixes it into all the surfaces.
...
which isn't at all necessary for model planes that aren't going supersonic, but whatevs
>>984171
>Arduino flight shield
Now we are talking of serious shit.
>>984149
>>984136
>Hey guys. I'm beginning with aeromodelism, and I've been studying the possibility of making this plane (F-22) in a future.
>Pic related is a diagram of the servos that I'll need (not even including landing gear and twin fans).
>How could I handle this huge amount of servos?
it would depend on if you want to be able to operate each separately or not. how complex of a controller do you want to use? No normal RC airplane controller will have the methods to control all this stuff individually.
like for example: the engine exhaust nozzles tilt up and down--but if you don't have a way to separately control them from the remote, then you can just mechanically link the engine nozzles to the elevators, since that way the nozzles would move and moving the nozzles the same as the elevators is the only (simple) way to move the nozzles that makes sense.
-------
Short answer:
If you wanted to make everything separately controllable (such as to have decoupled flying maneuvers) then there are 'arduino' 16-channel servo driver boards on ebay for $7. These are controlled by I2C and you can daisy-chain up to 62 of them total (62 x 16 = 992 servos possible). These don't just hook right on to a normal RC receiver tho.... and a normal remote would have no way to control them.
Military designs are designed under the assumption that they will have a virtually limitless budget for maintenance and fuel.
OP, you will not have this good fortune and your design should reflect that. Experienced ultralight fight enthusiasts use atmospheric temperature differences to extend their flight time to virtually indefinite periods, columns of rising hot air provide a lot of lift and bouncing from one to another is a very effective method to experienced users.
This website will show you the best design I've ever seen for a aircraft, it's literally designed to never land.
http://aeromodeller2.be/
The people developing this are literally personal heroes of mine, because they are proving hydrogen can be safe. Go check it out.
Forget about using military equipment to build your plane, to this day the cable and pulley system is the most foolproof way to fly. However, by all means rip off their designs as much as possible. Only steal from the best. Don't use vertical tail stabilizers, it's drag isn't worth the stability after flying wings have been made stable. Look at designs like the B2 spirit. I did say don't use military tech because it tends to be heavy as fuck but do everything you can to make fight stable while keeping it lightweight.
Lightweight solar panels are nice and I recommend using them if you can make a craft with a large surface area.
If you're using wood, mix ethanol and epoxy together. It'll turn that wood into a piece of iron with a fraction of the weight.
If your set on having turbines, I'd recommend small lightweight ones meant for missiles or jetpacks. The JB-9 jetpack is literally amazing, it has a flight time of ten minutes and two turbines.
I'm recommending using small turbines because you'd want a lightweight propeller to get it up to speed first. BMW motorcycle engines look like they can have a ton of weight taken off without compromising strength, look into the engine profiling done by hardcore racers. Propellers are more efficient than turbines at slower speeds and vice versa for turbines, if you can take advantage of airflow control.
I'm no expert but I'm trying to learn. Look into the hoverbike, it uses this engine if I'm not mistaken.
However, your design will want to take advantage of the methods hang gliders and ultralight flyers use.
You will want to be able to fly practically indefinitely, after all.
I'm assuming you want a manned craft, not a radio operated toy?
They are making some very advanced lithium batteries these days and ultralight solar panels.
I highly recommend designing something that will change the way people look at ultralight craft.
>How could I handle this huge amount of servos?
The simplest way? Y-cables. Lots of them. Drive both flap servos from the flap channel. Both rudders off the rudder channel. Both ailerons off the same channel (if you want differential, do it mechanically). I'd split the stabilators and nozzles into left and right, and drive the left cluster off one channel and the right off another, and give them elevon mixing. If you have two motors, control both of them from the same throttle channel. So that's what, 5 channels? Easy. 6 if you want retracts.
Alternatively, you could use a flight controller and program it with custom mixes. Something like a Naze32 gives you up to 6 seperate outputs from your 4 primary flight controls plus an optional mode switch, and you can also still bypass the flight controller and run signals straight from the Rx for any other functions (i.e. retracts and flaps).
Oh, and one more thing: fighter jets are not airliners; they can often encounter high AoA and thus require slat deployment at speeds well above flap extension speed. Therefore it doesn't really make sense to tie flaps and slats together like that - I'd consider maybe tying elevator and flaps together instead.
>>984340
>elevator and flaps
I meant elevator and slats. Flaps should be independent or maybe coupled to landing gear.
Dude that diagram alone looks like you need 5/6 channels at most. Almost any decent TX/RX you buy will be at least 6 channels. 8 channel controllers are not rare.
test
>>984286
Lol no, OP is looking for model aircraft.
There's no way one could make a manned f-22 on their own, unless they were like Elon Musk levels of rich and dedicated.
Just use regular RC controllers. And a co-pilot. Main pilot operates the flight servos that actually matter. Goose operates the axillary servos, including the one that opens the bomb bay doors that drop the dildo bombs.
>>985675
>Real thing only needs one pilot to fly and do everything
>RC model version somehow complex enough to warrant a crew of two
Who knew dildos could be so complicated?
>>985695
The real thing has three supercomputers built in to help the pilot and a purpose-made interface.
I don't think a model one is as difficult to fly, they are very light and slow in comparison.
I think an actual scaled down 20:1 f22 would be over 100kg or something.
>>985769
Or just use an in line gyro on the servo...
>>985771
no you misunderstand. it flies like a brick because it is not designed to be aerodynamic. it is designed to be stealth. aerodynamic shapes are smooth. radar can see continuous surfaces. so they break up the surfaces into many smaller polygons such that it will only reflect radar from one small panel in any direction so it appears to just be a single bird from any direction.
this is why they need sophisticated control hardware. because they are not able to be controlled by a pilot other than interpreting simple joystick commands like up down, faster, slower.
>>985774
Is it at least capable of gliding from a high place?
>>985784
not without computer control. there isnt even any direct access to any of the flaps on this thing. it's all routed through the computer so that it can adjust all the flaps together, in combination with its own sensors to fly where you tell it to go.
most aircraft arnt even capable of gliding. it's called a stall. when the speed drops below a certain point it loses lift and just falls like a brick out of the sky. the way to get out of this is to point the plane down and the air rushing into the intakes hopefully spins the engines back up and your speed increases in the direction of travel allowing you to get enough lift once you pull out of the nose dive. these kinds of aerofoils dont just glide like a paper plane, they require a certain velocity to maintain lift on their tiny wings.
pic related. this is as high as the wright plane could go.
>>985801
>most aircraft arnt even capable of gliding
>Stopped believing anything you say.
No. The vast majority of aircrafts have a glide slope that is quite reasonable. Every pilot is trained in how to locate a reasonable landing location within his glideslope and land there without power.
https://en.wikipedia.org/wiki/List_of_airline_flights_that_required_gliding
If you had said 'modern military fighters aren't even capable of gliding, which still isn't true if the avionics are still functioning, but I"d let it slide.
Even military non-fighters like the orion, u-2, b-52, B-2 (with working avionics) all have perfectly usable glide slopes.
>restart a low bypass turbofan/turbojet by nosing down
What is this, world war 2? No. That's insane. Supersoinc fighters specifically have engines that can't do this anymore because of how they bypass the air and how it's compressed. Most fighters are completely capable of restarting their engines through the engine starter. A simple engine out (eg, assuming there's nothing else wrong that caused the engine out) hasn't been exciting since the F-15 or F-14B
>>985830
what is this hose for?
and yeah that was my point. OP wants to build that jet to scale. he wants to know if he can glide it without integrated control of the control surfaces.
>>985840
>B-52 startcart dot jpg
https://www.youtube.com/watch?v=ZkYqDYuH4uo
I dunno, what hose?
>most aircraft.
That's my thing.
Most aircraft are perfectly fine gliding, and windmill starts have nothing to do with glide slopes. Your glide slope dictates what envelope you have to do a windmill start, but it's not the same thing.
>>985844
I guess I just had this idea of OP dropping his model off a cliff and it failing wiley coyote style.
how serious is a stall condition in a low flying aircraft though? I am probably wrong. I still dont understand how twin props fly with only one functional engine.
>>985853
A stall isn't the same thing as an engine out.
A stall is an interruption in airflow over the wings and control surfaces resulting in a loss of control and/or lift.
You can not even have an engine, like in a proper glider and never stall.
You can be afterburning in an f-4 jet fighter at max speed and stall into a flat spin that a human can't recover from.
Stalls and engine out are separate and neither is a death sentence give. The aircraft is in a good spot in its flightenvelope.
Twin/quad/eight props can fly with engine failures with other control inputs to correct for the offset thrust. Ot drastically changes how you fly the plane of course.
You might not be able to go full throttle on your remaining engine and fly in a straight line. Or your remaining engine might not be enough to keep you flying unless you keep it above 80% throttle or something. Everything changes and it is very particular to the aircraft and conditions but is generally perfectly possible to fly, usually because they are designed with that in mind. Like international flights in the us are required to have four engines so they have better chanches to survive engine failures.
>>985866
This also hardly relevant to rc planes. Even a cheap foam plane based on like a ww2 fighter has better than 1 thrust to weight ratio. You could hold it vertically and it would take off. The engines in rc planes are insanely powerful. You actually can make a brick fly and without any advanced avionics, just because the engine can push it I A straight line so fast.
Making the f22 with an advanced flight computer should be entirely for fun. It's totally possible for it to fly without doing anything as complicated as even having the forward slats or separate flaps/ailerons. Just cut ailerons and ruddervators and it's perfectly fine.
You probably won't even notice the difference between the real crazy computer f22 mockup and basic control surfaces cut into am f22 shaped brick
>>985866
>You can not even have an engine, like in a proper glider and never stall.
A guy I worked with would fly his Cessna whatever over to my town and we'd fly to another city to do work about once a month. One time he cut the engine just to show how safe the plane was. It felt like a wile e coyote moment when the forward movement slowed to what felt like a stand still. Just waiting for the thing to drop like a rock. It didn't of course because there was still enough forward speed to provide lift. He said we could glide probably almost to where we were going but something about flight plans and altitudes and stuff.
>>985866
so...
fighter jets can glide with an engine out?
>>985882
They can fly just fine with one/2 engines out. They fly even better with both engines and only one wing. http://uss-bennington.org/phz-nowing-f15.html
They have a glideslope with both engines out. But the bigger concern is if it's a f16 or f18 or one of the other 'unstable' (read: Modern) aircraft, it will be difficult to control without the computer and hydraulic assistance, so you need at least the apu engine running. If you can't start the apu you may as well eject if you're at a reasonable location because the last thing you want is your batteries dying when your 100 Ft off the ground about to make your unpowered landing. And you have an ejection seat which is awesome. If you're over enemy territory you need to weigh your chances if you want to glide another 1/4 mile or just eject right over the manpad that shot you down.
The thing when talking about mjlitary jets and engine failures and gliding is you don't assume it's a mundane failure, you assume it's battle damage.
>>985886
>imagines OP riding his 1/4 size jet
>ejects
>>985700
>supercomputers
Kek
More like early-2000s desktop computers
http://www.f-16.net/forum/viewtopic.php?f=33&t=25137
>>985769
>The real one is aerodynamically unstable
Longitudinally, yes. This can be rectified by simply shifting the center-of-gravity forward.
>and fly-by-wire.
So is this, technically. If you're referring to artificial stability, that's not magic either. Every quadcopter out there uses it these days, and likewise you can stick a $20 gyro control board, do a little PID tuning and get all the artificial stability you need. Or you could just add a bit of noseweight and eliminate the need to do so entirely.
Assuming you want this thing to fly...
Do a shit ton more research and get a lot more experience first.
I'd recommend you start off with an RTF trainer. Then you can move on to scratch building + expensive models etc...
>>984171
>>984197
>>984261
If your controller uses digital signal encoding then you can have a neigh limitless number of channels. The only limit to channels is how many physical servo connector pins your RX has.
For starters to control that many servos and get that kind of mixing you'll need a fully programmable TX. I'd go with the likes of the Taranis X9D Plus. Also some decent telemetry sensors, maybe even FPV gear if you're going all in.
Keep in mind as well, ducted fans (or jets) are loud and fast, so you'll need a rather large flying area w/o people nearby...
Also, pick a diff flight model, or an RC specific re-design of the F-22; as stated earlier in thread jet aircraft aren't very stable for beginners, much less at lower Reynolds #'s
