Show off your Aircraft designs!!

[zedextreme8177]

So basically, this is my design for a CESTOL (Cruise Efficient Short Take Off and Landing) aircraft. I will mention that I'm not an aeronautical engineer, just a young guy with a passion for aviation I come from a country with many short runways which are not accessible to normal jet airliners, so this is my incentive for this design, which is based on my research on the internet

I started the standard design for regional jets, then added an extra wing with enclosed ends to form a box-wing biplane. However, airflow interaction between the two wings (when placed so close together) reduces the total lift increase to just 15-20%

So I eliminated the horizontal stabilizer, and moved the wings to their respective positions. The lower wing is placed in the front so that it's downwash doesn't interfere with the upper wing. Blended winglets (which apparently provide the best efficiency on short flights) were added, with the rear winglets enlarged to double-up as horizontal stabilizers.

The engines are placed so that the exhaust blows over the upper wing surface, and when the flaps are deployed, the thrust gets deflected downward due to the Coandă effect. The thrust vector/reversal clam behind each engine can adjust the thrust either down to the wing or straight behind depending on the phase of flight (ie. straight behind during cruise for minimizing thrust scrubbing, and the resulting drag).

Anyways, enough talk! Best to enlarge the photos to see all the details (and any imperfections that might be there ) Here are the original sketches I drew:

And these are done on MS Paint (my first time actually painting an aircraft )

Passenger version

Cargo version

Would love to hear your opinions on the paintings, and some from any aeronautical experts on how to improve the design.

I will be adding more of them as I draw them up

 

[tonypanda]

wow U DID IT GREAT

 

[Venom800tt]

Not bad, would like to see this design as a 3d model
I do have one suggestion, and that would be to add a bit more wing sweep, since you have a cruise speed of Mach .92. That is getting into the transonic speed area, where high swept wings become important, at least if you want to be efficient. Cessna Citation X and Gulfstream G650 are perfect examples of this.

Maybe I should start a topic for people to post their aircraft designs, 2d, 3d, etc because I know there are others on this forum interested in the things that move in 3 dimensions instead of just 2

 

[zedextreme8177]

Thank you very much!

The wing sweep is something I have to decide, it should perform well at both high cruise speeds (which would come from the large engines needed for a good power-weight ratio), and low STOL speeds. High wing sweep is not good for STOL, so a low-drag cross-section would be needed (Supercritical aerofoil ). These are the times I want a wind-tunnel in my house

I really need to learn 3D modelling Would love to fly them in FSX or X-Plane

I could change the thread title to a general aircraft design thread Will do it once I get back to the PC.

 

[Venom800tt]

In that case I guess I shall post my STOL transport jet, my Mule. Was meant as a utility plane to be used in rough conditions. Now it kinda sprouted roughly a half dozen different variants, both military and civilian. Basic Mule is a civilian utility plane that can operate from rough field environments, ranging from ice and snow to grass and gravel. Engines are high mounted geared turbofans of my own design, which provide 30,000 lbs of thrust when unrestricted. Under normal conditions the engine's FADEC computers limit thrust to 20,000 lbs, for increased engine life. Only when heavily loaded or operating from hot and high conditions are the engines de-restricted. At least on civilian models... Military variants don't have this restriction.
Anyway some specs, which cover all models of the Mule:

Dimensions & Capacities:

Length:
68 ft (20.72 m)

Wingspan:
67 ft (20.42 m)

Height:
17 ft (5.18 m)

Crew:
2; 1 Pilot, 1 Co-Pilot (Mule)
3; 1 Pilot, 1 Co-Pilot, 1 Loadmaster (US-6A)
4; 1 Pilot, 2 Naval Flight Officers, 1 Sensor Operator/TFO (S-6A)


Empty Weight:
25,000 lbs / 11,340 kg (Mule)
27,000 lbs / 12,247 kg (US-6A)
30,500 lbs / 13,843 kg (S-6A)
33,000 lbs / 14,968 kg (ES-6A)

Max Takeoff Weight:
80,000 lbs / 31,751 kg (All Variants)


Fuel Capacity:
20,000 lbs / 9,072 kg
2,963 gal / 11,216 l



Performance:

Maximum Speed:
Mach .92 @ sea level (700 mph, 1,127 km/h)

Cruise Speed:
Mach .90 @ 30,000+ ft (9,144+ m)
Mach 0.85 @ sea level

Stall Speed:
60 kts (111 km/h)

Service Ceiling:
45,000 ft (13,716 m)

Rate of Climb:
N/A

Range:
3,000 nm (5,556 km), internal fuel
Unlimited with in-flight refueling

G-Limits:
7+ empty
4+ @ max weight

3- empty
2- @ max weight

9G structural limit

Takeoff Distance:
500 ft (152.4 m)

Landing Distance:
700 ft (213.36 m)

Thrust to Weight Ratio:
@ MTOW
Empty



Engines:

2 VAAS/GE GEV-30 high bypass counter-rotating geared turbofans,
30,000 lbs of thrust (9,071.8 kg) each
Cascade thrust reversers on each engine



Weapons:

25,000 lb (6,804 kg) maximum weapons payload carried externally
1 internal 25mm GAU-12 Equalizer Gatling gun, 500 rounds of ammo



Sensors/Countermeasures:

AN/APG-81 AESA multi-mode radar
AN/AAR-57 CMWS
AN/AAQ-24 DIRCM
AN/AAQ-37 EO DAS
EOTS
AN/ALE-47 CMDS
AN/ALR-67v3 ASR



Flight Control/Avionics:

Triple redundant Rockwell Collins flight control system
IBM Cell based main computer/avionics system



Landing Gear:

Dual nose wheel
Main gear with one wheel per strut
Arrestor hook



Control Surfaces:

Elevators
Rudders
Ailerons
Leading edge slats
Speed Brakes
Spoilers
Flaps



Construction Materials:

40% Carbon-Fiber composite
25% Titanium alloy
25% Al-Y-Li alloy
10% other



Glossary:

EOTS = Electro-Optical Targeting System
AESA = Active Electronically Scanned Array
MTOW = Maximum Take Off Weight
DIRCM = Directed InfraRed Counter Measure
CMWS = Common Missile Warning System
CMDS = Counter-Measures Dispenser System
MTOW = Maximum Take Off Weight
ASR = Advanced Special Receiver
EO DAS = Electro-Optical Distributed Aperture System
kts = Knots

Yeah, I kinda try to think my ideas through as thoroughly as I can lol

 

[terminator363]

@OP

I understand you can't use a rudder because of your engines, and even if it was added the engines would disturb the air around meaning you wouldn't really be able to influence the aircraft direction too much. Thing is, those winglets aren't enough. Also wouldn't it be really back heavy and light at the front?

 

[Exorcet]

I think you should try revisiting the box wing design. If you offset the wings from the each other, they won't interfere as much.

Something like this

http://www.aeronautics.nasa.gov/docs/ar99/8-3b.gif

This will help with the moment of inertia (this aircraft might fly like the space shuttle which exhibits wrong way behavior when changing pitch because of its weight distribution) and extending the wiglets from one wing to the other could reduce drag.

Mach .9 is also a really high cruise speed. Lowering to the .8's is probably more realistic. If you want good STOL performance, you will want a highly cambered/curved wing, but that becomes a negative at transonic and supersonic speed.

And you MS paint abilities are amazing. I thought those were from CAD at first.

 

[zedextreme8177]

@Venom800tt: That's a beautiful design, love the overall shape and great modelling! 👍👍 My only suggestion would be to use a T-tail or a cruciform tail. With the current design, the horizontal and vertical stabilizers would be straight in the engine thrust flow I wonder if you could port that to FlightSim!

@OP I understand you can't a rudder because of your engines, and even if it was added the engines would disturb the air around meaning you would really be able to influence the aircraft direction very much. Thing is that those winglets aren't enough. Also wouldn't it be really back heavy and light at the front?

The two winglet rudders should be enough to compensate. This design ended up quite resembling a Beechcraft Starship:

The winglet rudders would not need to be as proportionately large as they are on the Starship, since this aircraft has a longer fuselage, the yaw moment-arm would be increased.

As for the tail heavy bit, this is counteracted by increasing the lift on the rear wing (you can notice it's a bit larger than the front). That in combination with the engines blowing on the upper surface of the wing would be more than enough to lift the heavy rear-end (pun intended ).

A reason for designing the rear wing with more lift, is that the front wing should ALWAYS stall first! If the rear wing stalled first, you'd have little chance of regaining control since the aircraft would pitch up even further

In the event of an engine failure, asymmetric thrust won't be too much of an issue since the engines are placed quite close to the center line.

@Exorcet: Thank you! That's an interesting design, never even thought of that. I do think of reducing the cruise speed, but since the engines are quite oversized compared to other RJ's, I'm still thinking. Who knows, there might be an aerofoil developed which allows for both low and high speed performance

 

[Venom800tt]

@Venom800tt: That's a beautiful design, love the overall shape and great modelling! 👍👍 My only suggestion would be to use a T-tail or a cruciform tail. With the current design, the horizontal and vertical stabilizers would be straight in the engine thrust flow I wonder if you could port that to FlightSim!

Thanks!
The tail was done that way intentionally lol
It's structure is somewhat overbuilt, and designed to be in the exhaust flow to provide for more stable low speed handling. Even at stall speed, the aircraft will still have directional control because of this. Think of it as a short of ghetto thrust vectoring. Plus, prop aircraft do this all the time
Oh, and I also wanted to keep the aircraft low enough to fit inside of an aircraft carrier hanger deck. Going with a conventional or T-tail would make that a lot more difficult, since they tail would need to be much taller to provide enough yaw control.

 

[Exorcet]

The winglet rudders would not need to be as proportionately large as they are on the Starship, since this aircraft has a longer fuselage, the yaw moment-arm would be increased.

That depends on where your center of mass is, however the bigger issue is that MOI created by having such big wings at both extremes of the aircraft. You design probably needs bigger stabilizers because of that.

@Exorcet: Thank you! That's an interesting design, never even thought of that. I do think of reducing the cruise speed, but since the engines are quite oversized compared to other RJ's, I'm still thinking. Who knows, there might be an aerofoil developed which allows for both low and high speed performance

Supercritical and low speed airfoils do in general have a similar shape, though they are optimized for cruise rather than takeoff/landing. Another solution could be very large flaps and slats like on the F/A-18 E. The issue with Mach .9 is that you will almost certainly be creating some decent sized shock waves on the airframe, and the best way of dealing with them involves giving up lift. For a short trip, it's not a big deal, but it can cut your range drastically.

You seem to know quite a bit and have a lot of interest. This plane might fly one day, keep it up.

 

[zedextreme8177]

Thank you very much! I will use those ideas and advice in any redesign I do, and might use smaller engines for it

@Venom800tt: I never thought of that Though you'd probably need to use more heat resistant materials, your use of high-bypass turbofans should not be too much of an issue. I would love to see some of your other designs, keep it up! 👍

 

[Venom800tt]

Thank you very much! I will use those ideas and advice in any redesign I do, and might use smaller engines for it

@Venom800tt: I never thought of that Though you'd probably need to use more heat resistant materials, your use of high-bypass turbofans should not be too much of an issue. I would love to see some of your other designs, keep it up! 👍

Don't really need anything uber heat resistant. Tail is carbon fiber like the rest of the aircraft. By the time the flow hits the tail, it is relatively cool since the nozzle is a mixed design, where bypass air mixes with hot exhaust. On the Embraer ERJ-145 regional jets at work, the exhaust at idle is only warm from 15 ft behind lol

And here are a couple of my other designs I like a lot, both fighters:
F-58A Hammer, 2030's heavy fighter

Specs Here

F-XX Advanced Light Weight Fighter, 2020 F-16 replacement and F-35 competitor:

Incomplete specs Here