Does Aerodynamics Affect Train Speed?

[Electricsteam]

I thuoght this would be an intreting topic! The main goal of this topic is to decide if areo-dynamics effect the speed of lego locomotives because me and my friend are having a competition to make the fastest PF steam locomotive.

I would like to hear what you think . And help me find good locomotives to build for the competition.

---Rules---

Either 6-8 large BBB/Lego drivers

Only 2 PF S/M motor or 2 PF Train motor

No moding motors or bricks except tubes or pole?

Those are the rules me and my friend decided on.

They way we will decide is the fastest is by getting the locomotive from Point A to Point B in the fastest time.

I will post the Locomotive I choose as a Moc once I decide!

[twenty6twelve]

As aerodynamics affects the speed of everything, regardless of size, there is no doubt that it is also a factor in Lego trains. However, aerodynamics are far less of a concern to Lego trains in comparison to the super-tight radius of the curves which will derail all but the heaviest trains at high speeds!

[Electricsteam]

As aerodynamics affects the speed of everything, regardless of size, there is no doubt that it is also a factor in Lego trains. However, aerodynamics are far less of a concern to Lego trains in comparison to the super-tight radius of the curves which will derail all but the heaviest trains at high speeds!

Im talking about a major diffrence in speed sixoh and we are using a super wide radius turns.

[roamingstop]

ElectricSteam; it seems you have not been around the AFOL community for too long... (if AFOL?). Anyway the French LUG (Freelug) has a LGV (Lego Grand Vitesse) line they often use to break speed limits. The biggest issues there are not aerodynamics but keeping the train on the track at high speed whilst minimising the drag caused by poor wheel friction.

http://www.freelug.org/

http://www.freelug.o...php?article1232

No two motors will be identical; but the differences should be minimal if the type of motor is the same (PF and RC are not the same). Secondly the linkage mechanisms and any friction will also be important. By the time you iron out all of these issues the aerodynamics will have little impact. No matter how you buld the studs will cause minor turbulance which will also cause back-drag. Making models smooth helps; but also consider how the air flows over the carriages. Look into the physics of aerodynamics to gauge whether a Lego design will really work well.

Edited November 28, 2012 by roamingstudio

[Electricsteam]

ElectricSteam; it seems you have not been around the AFOL community for too long... (if AFOL?). Anyway the French LUG (Freelug) has a LGV (Lego Grand Vitesse) line they often use to break speed limits. The biggest issues there are not aerodynamics but keeping the train on the track at high speed whilst minimising the drag caused by poor wheel friction.

No two motors will be identical; but the differences should be minimal if the type of motor is the same (PF and RC are not the same). Secondly the linkage mechanisms and any friction will also be important. By the time you iron out all of these issues the aerodynamics will have little impact. No matter how you buld the studs will cause minor turbulance which will also cause back-drag. Making models smooth helps; but also consider how the air flows over the carriages. Look into the physics of aerodynamics to gauge whether a Lego design will really work well.

1.We are only building the Steam loco. and the Tender of the steam loco. 2. We are not trying to break any record. 3. We dont want to fry the motor.

[locoworks]

use as few wheels as possible in the rules, every axle means more resistance. no coupling rods would also help, in fact, the less moving parts the better. i have 5 inch gauge electric loco's and two with with the same 4 motors. one is a twin axle 040, and the other a 4 axle bo bo. the 040 is one mile an hour faster than the bo bo, 12 instead of 11. there is a weight difference working against the bo bo but the extra axles are the real drain.

[LEGO Guy Bri]

As others have said friction and weight will affect your locomotive the most. They are too small for aerodynamics to really make a difference before weight and friction do, though I wouldn't take it completely out. Like I wouldn't make it very tall or mis-shapen. You should focus on reducing friction. You can always go down to your local hobby shop and get some graphite powder (in a small tube) and shoot a little where the metal axle makes contact with plastic (I would not apply to motor). I used this stuff the 2nd year I ran Pinewood Derby (didn't the first) , many years ago, and came in 2nd overall. I believe WD-40 would also work, it's a very lightweight lubricant and degreaser. I've used that to help some of my old Hot Wheels/Matchbox cars and squeaky LEGO wheels. It just leaves a smell and a light oily residue, but I don't mind it.

Edit: I spelled squeaky wrong

Edited November 29, 2012 by LEGO Guy Bri

[Duq]

I don't have the numbers or formulae to prove it but my gut feeling is that the effect of aerodynamics at the speed of a Lego train will be negligible.

[Locomotive Annie]

Wow, that LGV line is something else!

Does anybody know how they built their trackwork because it's definitely no off-the-shelf item.

[Bamos]

Electricsteam

Unless you are racing outside into a severe headwind it will not make any difference.

But driver size, weight and gearing will. With a larger driver the wheels turn faster there for more speed. Gearing is the opposite the smaller the gear more speed. So technically a toy story 0-4-0 driven of a 9 volt or PF gearbox with the largest drivers you can find should be the fastest.

But it will not corner at all.

Bill

[LEGO Guy Bri]

Does anybody know how they built their trackwork because it's definitely no off-the-shelf item.

I asked a while back about how they did this. I was told it was built, with regular hardware items, with a fabricated mold, and hardening resin. LEGO bricks where placed inside to take up space so less resin was used, but I guess you can use something else

Edit: Found it!

Check my profile under Train Stuff (scroll down), I always save links to stuff I find interesting or helpful

Edited November 29, 2012 by LEGO Guy Bri

[Electricsteam]

People.... Look at the rules of the competition....

---Rules---

Either 6-8 large BBB/Lego drivers

Only 2 PF S/M motor or 2 PF Train motor

No moding motors or bricks except tubes or pole?

I am not aloud to use lubacant or modify the bricks in anyways and it has to be a steam loco either ?-6-? or ?-8-?

I'll post what I've been working on later ....

[Locomotive Annie]

Thanks LEGO Guy Bri, - I don't know if I would try it myself, but it certainly was interesting to read the article.

http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.freelug.fr%2Fspip.php%3Farticle1220&act=url

[Bamos]

electricsteam

Rules are open to interpretation are you limited to either 0-6-0 or 0-8-0 arrangement or just 6 or 8 drivers if it’s the later you could build a articulated engine like a Pennsylvania duplex but without the leading or trailing trucks an 0-4-4-0 .

Or if the drivers do not have to be powered use a PF powered front and rear truck like a Hudson 4-6-4 the L and M motors use more gearing to change the direction of power and any change will cause resistance and slow your train the regular train set motors are made for speed all others are for torque.

Bill

[zephyr1934]

6 or 8 drivers could be 8 blind drivers that never touch the rails, then use a pair of PF train motors as the pilot and trailing trucks, e.g., from brickworld 2010 I think it was someone from NILTC had used flanged drivers and raised them off the track

This photo is unflattering, but when it was running you wouldn't notice (it took me a day or two to catch it) since the drivers had a separate motor to keep the rods spinning.

Also, it sounds like your race is from point A to point B, but is it from a dead stop or can you pass point A at speed? If the latter, you can add gearing after a PF medium or XL motor to speed it up considerably at the expense of torque and probably acceleration.

So is your competitor also reading the forums? Or will this turn out to be a race between the EB advice and the Flickr advice? (grin)

[hoeij]

use as few wheels as possible in the rules, every axle means more resistance. no coupling rods would also help, in fact, the less moving parts the better. i have 5 inch gauge electric loco's and two with with the same 4 motors. one is a twin axle 040, and the other a 4 axle bo bo. the 040 is one mile an hour faster than the bo bo, 12 instead of 11. there is a weight difference working against the bo bo but the extra axles are the real drain.

More axles doesn't mean more resistance (more weight = more resistance).

[Electricsteam]

The train I've been working on is a mix between this http://www.steamlocomotive.com/streamlined/scrapped/up2906-a.jpg and http://www.google.com/search?hl=en&client=safari&tbo=d&tbm=isch&q=norfolk+and+western+611&revid=1941499837&sa=X&ei=dey2UI3DK8aQ0QGd9YGwCA&ved=0CDoQ1QIoAQ&biw=1024&bih=690

Edited November 29, 2012 by Electricsteam

[LEGO Guy Bri]

People.... Look at the rules of the competition....

I am not aloud to use lubacant or modify the bricks in anyways and it has to be a steam loco either ?-6-? or ?-8-?

---Rules---

Either 6-8 large BBB/Lego drivers

Only 2 PF S/M motor or 2 PF Train motor

No modding motors or bricks except tubes or pole?

Those are the rules [my friend and I] decided on.

I am a little confused as to why you wouldn't be able to use any lubricant, as it's not modifying anything, especially if these are 'your' rules. I use it on my trains as regular maintenance and to keep my 9V's running for years to come... (I guess I would be immediately disqualified if I were in it ) But to each his own

More axles doesn't mean more resistance (more weight = more resistance).

I agree with the weight part, but more axles means more metal to plastic contact = more friction, no?

[Electricsteam]

I lost He used 2 of the train motors on the large drivers which game him very increased speed...

[LEGO Guy Bri]

Did you get any pictures of the locos racing or at a stand still?

[Electricsteam]

Did you get any pictures of the locos racing or at a stand still?

Nope I talked one of my old teachers , Son who is an English teacher just like his Mother but they wouldn't let me have a camera in the school