AndyCW

Can you show us a pic of one that has been well used to get an idea of the damage incured during operation? This would also explain the performance of your crawler with apparently open differentials. v/r Andy

It is a cross between this and my KOH truck. This looks better with the elimination of the extra link. I like building in this method because it allows me to isolate different modules and work independantly. You can improve the axles independantly of the chassis and vice versa as well as working on the body separtely from everything else

My latest iteration has a four speed transmission. I am working out the kinks right now. I may create myself a custom 9.6 volt battery pack to follow your trend.

This transmission/output selector will work fine in my last crawler chassis. I used a 24t, worm, and PF Med to shift gears. I ended up twisting a 4l axle w/stopper, but it worker fine. 9:1 axle plus transmission meant that at 7.4 Vdc I had some trouble with really large obstacles in low gear. Your higher voltage should mean that you will have no problems. Higher speeds almost require return to center steering. It was hard to drive well in high gear. Why do you have the extra link on the top of the axle? You can eliminate it if you increase the level of triangulation on your four link. This looks promising. v/r Andy

Welcome to the forum. Excellent intial entry. The suspension looks quite flexible. This must help out a lot with the open differentails. Really like the wheel caps and body. v/r Andy

I built one of these gearboxes with 2 RC Buggy motors. The shifting mechanism worked flawlessly. Here is a video of the shifting mechanism in operation. It uses a PF medium motor, a 24t clutch gear, a worm gear, a 2 stud lever arm, and a 9 stud link to create 1 stud of travel. It needs stops to prevent over travel and the clutch gear prevents the motor or framework from becoming too stressed.

Welcome! I agree that it looks more hummer than jeep, but that doesn't matter. It looks good and performs good. Any details about gearing, motors, etcetera. We would all like some pics of the under carriage and maybe some pics of the chassis without the body installed. We want to know how it works. v/r Andrew

With studded models we tended to build from the bottom up, but with studdless designs we build from the center outward.

Wow. Body work is something I need to improve on and your car has some great "lines". I kind of get a Nissan GT-R vibe from it. v/r Andy

Welcome to the forum. Lurking here is a great source of inspiration. Soak it up. Experiment. Share what you have created and grow. Can't wait to see your first MOC. It will inspire me in some way. Just like everything else presented on this forum. v/r Andy

I like the buggy motor integration and the underside. Hopefully IR control can keep up with available power and speed. Keeping the suspension soft will help with the differential and overal tire contact. If front suspension is effectively softer than rear, then it may lift a rear tire on corning and with an open differential cause wasted power. v/r Andrew.

Great first build. It is better than my first crawler. They only get better from here. Understanding fullscale crawler design and the reasons behind them will improve lego cralwers. -Caster angle -Kingpin inclination -Ackerman geometry -Pinion angle -RTI http://en.wikipedia....mp_travel_index -Steering angle -Turning circle Etcetera v/r Andy

Welcome to Eurobricks! Looks great. I look forward to more. This place is a source of inspiration and the more people contributing the better. v/r Andy

I frequently get inspired by other creations on this forum and try to implement others ideas into my own stuff. I try to build in modules to break the build up into manageable parts. I also try to build in a leap frog manner. Create v1 of a module, see the errors, and create v2 while not parting out v1. This allows me to compare the two approaches and select the better of the two. Dismantle the loser and wash, rinse, repeat.

You might want to shift more of the weight forward in order to make the rear wheels loose traction Also, your rear suspension setup causes the rear tires to "plant" as the vehicle accelerates. This is good for traction, but not so good for drifting.

Wow looks great and goes like stink. It will definitely drift with two 5292 motors. The drive train and overall chasis looks like something I have been working on. It seems that sometimes there are only so many good solutions to the same challenge. v/r Andy

I have been thinking about after market tires on the super street sensation wheels. I only say this becasue of the positive offset in these wheels. Has any body done this before or researched which tires would fit if any? The idea is to create more room for reduction hubs and get better steering. I do not see these wheels on many Mocs and it would be nice to see off road tires mounted on them. Are they even any good for this endevour? with this tire http://store.rc4wd.com/Rock-Crusher-XT-22-Tires_p_730.html v/r Andy

The drive shafts need to be the same length as the suspension links. This way they move through the same arc during suspension cycle. The drive shaft should be on the same angle as the suspension links. The other solution is to utilize telescoping driveshafts.

Looks good. I am trying something similar, but am using smaller tires and less voltage. I have previously tried direct drive 8070 tires, v2 ir rx, and 5292x2 motors @ 7.4 vdc. It was pretty fast, but could not drift and spin tires at will. This is why I scaled down. Your greater voltage may negate this shortcoming. Hope to see a chasis soon. v/r Andy

The material used in covering RC planes is commonly known as Monokote. It provides a cleaner surface and contributes to the models overall strength.

I can contribute what little I know about propellers. These are rules of thumb. They do not apply in all situations. The length of the prop determines static thrust. The pitch of a prop determines pitch speed. The fewer blades on a prop the more efficient it is. Reduction drives reduce efficiency What little I know about wings Long wingspan and short chord wings are the most efficient Short stubby "hershey bar" wings are easy to make, strong, and have good stall characteristics Delta wings have poor stall characteristics The power requirements for rotorcraft far exceed the requirement for fixed wing aircraft. For example, a 1946 Taylorcraft outfitted with a Continental engine produced 85hp and has a maximum gross takeoff weight of 1500 lbs. This aircraft has sufficient performance. A mosquito helicopter equipped with a MZ301 engine also makes 85hp and has a maximum gross takeoff weight of 720 lbs. It has sufficient performance. The size and weight difference between these two types of aircraft is large. The power limitations of lego make a fixed wing model much more likely to fly than a rotorcraft, given that a suitable wing and fuselage structure can be assembled. http://en.wikipedia.org/wiki/Taylorcraft_B http://www.composite-fx.com/compfx/XE3.html A control line model may be the best interim solution. This would allow you to leave the batteries out of the airframe by using long power cables. You could focus on structural integrity, controlability, and lift. WIth these things resolved, you could then transition into free flight with batteries aboard and then free controllable flight. http://en.wikipedia.org/wiki/Control_line v/r Andy **I am pursuing a degree in aeronautics, am employed as a unmanned aircraft pilot, and I have my pilots license. I also fly RC planes in my spare time.

This is what Power Puller wheels are They are for sale here http://www.bricklink.com/search.asp?colorID=67&itemID=47657 Holy Cow!! Those prices are unbelievable. Glad I got my set a long time ago when I bought the 8466 during its production run. v/r Andy

Your solution has potential. One thing about this setup though. Suspension cycle causes significant lateral movement of axle, because of the angle of the torque arms. This also means that when the suspension encounters an obstacle the lateral forces against the suspension cause it to try to cycle. This movement can cause the suspension to bind and in some extreme cases fail. Measure wheel base with suspension unloaded, then measure wheel base with suspension loaded. The difference should be negligible. There is a reason this style of suspension with these angles does not exist on full scale crawlers. The torque arm needs to be as close to level as posible and then you can adjust the angle of the "H" frame to get the desired caster. Does this make sense? Does anybody else see what I am saying? Am I way off base? I see whay Zblj is saying too. The axle going between the portal hub with the 20t gear on it bears all the weight of the "body". v/r Andy

Wow. I actually said WOW out loud while watching the video. The turning radius is amazing for such a large vehicle and the locking differentialls are also amazing. All it needs now is a plethora of buggy motors for power. Muhaha!!! My only worry is about the strength of the steering and its ability to overcome obstacles.

Like so many threads on this forum, you have inspired me. I am thinking about a much smaller truck that utilizes the small turn tables and linking the axles via gears.