MotoGP aerodynamics

In the last test IRTA in Sepang, Yamaha showed the next step in MotoGP aerodynamics.

Fairing with ducted vanes

Technical regulation is forbidden aerodynamic appendices, therefore if you want to work with aerodynamic, only you have shape and ducts in the fairings.

Fairings are reason for aerodynamic existence, and the first goal is to down Cx in the motorbike.

Low Cx is less aerodynamic drag, and more top speed with same power, but this is dead end way when the top speed is all.

We take Honda RC213V values,

• width = 0.645m
• height = 1.110m
• Area = 0.562 m2 (Elipse área wuth height and width)
• Cx = unknow

However we have hayabusa Cx = 0.561, and could be estimate that the MotoGP more and less 0.5 and 0.6

	Cx	200 km/h	300 km/h	355 km/h
Hayabusa	0,561	45 HP	152 HP	252 HP
MotoGP	0,5	40 HP	136 HP	225 HP
	0,6	48 HP	163 HP	270 HP

We could see that the top speed is reachable by motoGP is the same that, but big part of circuit the power is superior than you need, the famous wheelie is this fact, engine to provide more power that bike could take to increase the speed.

Conclusion, top speed is only one point in track and more than 90% in the track, engine provides more power than motorbike can manage it.

Therefore, 90% in the track, we can power waste.

How? One way is aerodynamics effects, in the 2016 season we saw wings in all motorbikes, but in 2017 is forbidden wings, but wings are not all aerodynamics. we could explore two ways,

1. Slots and coanda effects
2. Lifting body

Yamaha show the first field, with ducted vanes to provide Coanda effect. is for air viscosity create boundary layer and air follow this profile meanwhile dont broke it, (stall effect).

Coanda effect follow the profile

But the coanda effect has other behaviour, and this could see in the Hunting H126 and it jet flaps.

jet stream drag the surrounding air in the same direction

Jet stream, deflect the air ans create lift

You could work with this effect, and create air paths in the surface, like diverterless, this effect could see in the F35 Lightning II engine intake.

This is DSI shape and it has other advantages in supersonic speeds

Lifting body create lift forces without wings, due to the body is a wing

With this effect and "dowforce" body, and ducted jet stream we could create down force, like the old wings.

Drag creates for in air intake is converted in downforce. Purple lines is air flow.

One point where could be create this effect is in the nose fairing

The nose is a big surface where Coanda effect works, and it begins the rest aerodynamic behaviour.

Sepang test,  M1 show this ducted

Yamaha M1 ducted vanes

If the make the first calculates with the effective vanes, and only the effect the flow deflection and Cx=1 (all air into the ducted is deflected).

• Intake width = 0.1m
• Intake height = 0.3m
• Intake area = 0.03 m2 

YZF-M1

200 km/h

300 km/h

350 km/h

2 Ducted vanes

11,6 kg

26,1 kg

36,5 kg

MotoGP wings analysis

Then of MotoGP season 2016 where the all motorbikes y all categories was mount wings.

Today is banned, but I'd like on resume of simple analysis of effects and how it works. 

I am sure  that in the future the aerodynamics into motorbike have more weight in the design, the aerodynamics is not high relevant value, but in one world, where each tenth could be mark win or lose one race, aerodynamics can provide this tenth.

Aerodynamics basic concepts

Angle of Attack

The main effect is the angle between air and profile depend lifts generate, until one point where profile lost lift and only provide more drag, (stall angle)

Angle of Attack

Lift and Drag Equations

D is the drag force, which is by definition the force component in the direction of the flow velocity

L is the lift force, which is by definition the force component in the perpendicular of the flow velocity

  is the air mass density  1.205kg/m3.

v is the flow velocity (motorbike speed).

A is the reference area, (wings surface).

Cd is the drag coefficient provide for NACA profile data. 

Cl  is the drag coefficient provide for NACA profile data.

For calcule I used information with NACA profiles (this information is public in NASA webs)

Aerodynamic analysis 

Wing analysis

Ducati GP16 courtesy from Ducati

I estimate several measures

• Wheelbase 1400mm
• Rear SAG with pilot 30mm
• Fork travel 110mm
• Pitch full brake (fork fully compressed, rear wheel without load, rearshock extended) 5.7º
• Wing area 250mm x 100mm

Ducati GP13 braking

In the front part I used a thin profile NACA 65-206. This enter in stall quickly and provide low lift (Cl < 1) (down force) and low drag, this wing was used for Yamaha YZF-M1

• Straight mode with motorbike with full gas we put the Angle of attack (AoA) 6º
• In full brake the motorbike pitch 5.7º, therefore the AoA is 11.7º

NACA 65-206 charts

With 11.7º, this profile is in stall, this point is in brake, therefore Drag increase and provide a braking extra. The table provide the several data (10 N ~ 1 kg ~ 2.3 lb)

NACA 65-206	6,0º					11,7º
	100 km/h	200 km/h	300 km/h	350 km/h		100 km/h	200 km/h	300 km/h	350 km/h
L	8,14 N	32,54 N	73,22 N	99,66 N		2,32 N	9,30 N	20,92 N	28,47 N
D	0,46 N	1,86 N	4,18 N	5,69 N		1,39 N	5,58 N	12,55 N	17,08 N

In the side part I used a thin profile NACA 6412. This provide high lift (Cl > 1) (down force) and high drag, this wing was used for Ducati GP16

• Straight mode with motorbike with full gas we put the Angle of attack (AoA) 7.5º
• In full brake the motorbike pitch 5.7º, therefore the AoA is 13.2º

NACA 6412 charts

With 13.2º, this profile provide more lift, this point is in brake, therefore provide more force to tyres (like a weight) and provide a braking extra. The table provide the several data (10 N ~ 1 kg ~ 2.3 lb)

NACA 6412	7,5º					13,2º
	100 km/h	200 km/h	300 km/h	350 km/h		100 km/h	200 km/h	300 km/h	350 km/h
L	17,43 N	69,73 N	156,89 N	213,55 N		5,81 N	23,24 N	52,30 N	71,18 N
D	0,23 N	0,93 N	2,09 N	2,85 N		1,39 N	5,58 N	12,55 N	17,08 N

However, these profiles try to create less drag possible, therefore  if you have enough power to waste in drag, you could be increase the Lift forces. 

For example we can increase AoA without stall and increse Lift with slots in the profile 

In the F1, the top in racing aerodynamics Cl is over 3

Source Racecar Engineering

If we calculate with Cl 3 

Ranurados	Cl 3
	100 km/h	200 km/h	300 km/h	350 km/h
L	34,87 N	139,46 N	313,79 N	427,10 N

Each wing, generate 43kg with 350km/h, with 4 wings (one front one lateral, in each side) reach  174kg , this is the same weight of one MotoGP without rider

Behavior effects 

Another effect is the rider change his position in the bike, this create changes in aerodynamics

Motorbike Magazine courtesy

In corner when the rider try to leave the bike vertical and launch his weight to turn side, it create a wall where stop the airstream, and the lateral wing lost efficiency, and the other side create a roll effect like the rider put weight in the opposite side, this effect aid to take the turn.

Other effects in in the brake the pitch increase the Drag and Lift, and this provide more capacity to brake.

The antiwheelie effect, but normally, the speed in the exit is less and this effect is not the more important, beacuse, the wheelie is stronger in short gear, and this translate to low speeds

General drag, the vortex could be create two effects

1º Low the general drag like a golf ball, locate vortex provide less general drag

Locate vortex decrease the general drag 

NASA studies

2º Create a concentre vortex behind the bike, where concentrate turbulence and the motorbike behind shake by this turbulende. The air intake to engine could be affected for this tubulence. In 2016 season  riders complained for this effect. 

Security

The problem is if wing hit a rider in one accident or overtake. We could see that Force that must withstand so that it does not brake the fairing, therefore it must and hard part and could be injure to riders. Cruchtlow  warn this effect, and he has reason.

This is the first reason to ban the wings, other reason is cost increase due to aerodynamics studies.

In the future I will develop other post with how develop aerodynamics forces in the motorbike without wings.

Auto Rotation Re-Entry system ARRE

This project is a one presentation of one project that I did in the ESA Headsquarter in Noordwijk, into of program REXUS BEXUS

This project was presented for Sounding Rocket part (REXUS).

ARRE System

The main purpose of the ARRE will be the study of the re-entry systems based in auto-rotation property. This system is seems the autogiro's system and the re-entry system "Roton". The difference with these programs is the blades’s position, basically by having an offset between the blades and the rotor axis.

This experiment will try to recover a capsule with a payload after being released from REXUS rocket during nose cone ejection.

Low orbit re-entry speed is developed due low mesospheric drag, allowing the experiment reach high free fall speeds before entering the troposphere.

During the mesospheric branch, the rotor blades will fully deploy, having in mind the study of possible drag at these altitudes. While the atmosphere is not dense enough to generate any significant lift, the blades will trying to recover some energy in “windmill” configuration, converting it to the highest possible spin speeds. This speed will tell us how much interaction we obtained during mesospheric flight.

            As in stratosphere the density begins to grow, the accumulated spin energy will be used to damp slightly the free fall acceleration. The rotor has variable AoA (angle of attack) mechanism, allowing some actuations. After the “windmill” configuration stage, the blades will track an optimal autorotation profile so maximum energy is recovered and goal descend speed can be archived.

            The blade´s airfoil will be optimized through multidisciplinary approach, so extreme performances of whole system could be archived.

Rocket placement

Inside the REXUS rocket, the ARRE experiment will sit inside the nose cone.

This placement is necessary because to the experiment should be released in upper layers of the atmosphere and there is no need in precise apogee positioning, so the experiment can just be thrown off with the nose cone,

Flight Stages

The experiment in the Rocket, the control system will be in stand-by before the launch. The system will be just recording data of the temperature sensors and control heaters.

• At T0 seconds, in the launching moment, the control system initiates the second stage. This stage will record data from the IMU and temperature sensors and control heaters.
• At time T0+60 seconds after launch, on the nosecone ejection, the system will initialize heaters on the electronics and blades angle’s sensors.
• At T0+66 seconds all sensors will be activated in the separation moment.
• At T0+150 seconds in the apogee point, the pyrotechnics will initiate and release the blades.
• After the apogee point the system will be in a controlled falling while the auto rotation system will decrease and control the falling speed. The control system will try to reach the landing point with GPS flight control and IMU stability control.
• Near to the landing point, the ground proximity sensor will activate and initiate rotor engine to provide a softer landing.

In the ESA is typic develop in each mission patch Our Patch of mission was the famous image that the knight Quijote goes against a windmill.   You can download the study in pdf here