777 HAUL TRUCK (1/12 size)

[DADSGARAGE]

Originally Posted by Espeefan

Wow, this is a really great project! I'm subscribing. Looking forward to the updates as they come.

Thanks...glad you like it!! Slowly getting it done....as soon as I decide on a place to store pics I will continue to show more of the build and bring it up to date....

[doodlebug]

Looking Good, If you decide to swap out the rear axle, this an idea to take a gander at.
http://www.surpluscenter.com/Power-T...ET-13-1500.axd
Cheer's, Neil.

[DADSGARAGE]

That would work....if it was a bit smaller or if this truck was a bit bigger...LOL

[RCP57]

Looking good man! I can see that it won't be long now and it will be running! I also know from experience that it sucks to have a truck without a loader so something tells me that the loader will be started pretty soon!

That's a good find Neil. I've never seen one that is that small. Too bad there isn't a place like that in Canada to buy from.

[DADSGARAGE]

Originally Posted by RCP57

Looking good man! I can see that it won't be long now and it will be running! I also know from experience that it sucks to have a truck without a loader so something tells me that the loader will be started pretty soon!

That's a good find Neil. I've never seen one that is that small. Too bad there isn't a place like that in Canada to buy from.

There is a place here in Canada it's called Princess Auto...well almost...LOL
(don't tell anyone...but I tried this thing out at the shop today....HEEHEE..)

[RCP57]

Originally Posted by DADSGARAGE

There is a place here in Canada it's called Princess Auto...well almost...LOL
(don't tell anyone...but I tried this thing out at the shop today....HEEHEE..)

Princess doesn't have enough junk anymore! Too much made in China new stuff!

...and how did it go???? Did it steer???

[DADSGARAGE]

How did what go ??? Can't tell ya !!!
( Hey man.... I told you not to tell anyone !!!!..... LOL....I will add more soon....)

[JAMMER]

Great job on the 777 lot of nice ideas and it also helps to have a water jet close at hand. You have put some great thought into this build and it shows. I would like to do one to match my 1/12 scale excavator with some changer to what you did. Keep up the good work you have a talent. Ed

[DADSGARAGE]

Originally Posted by JAMMER

Great job on the 777 lot of nice ideas and it also helps to have a water jet close at hand. You have put some great thought into this build and it shows. I would like to do one to match my 1/12 scale excavator with some changer to what you did. Keep up the good work you have a talent. Ed

Hi Ed...Thanks....and yes having access to a waterjet is a big plus!! Good thing....because it supplies the "talent" !! Hope my build can help you with yours...if I can be of help in anyway let me know. Thanks again glad you like it....

[doodlebug]

I see what you mean about "SPACE".
Cheer's, Neil.

[DADSGARAGE]

Thanks for the link!!...yes a diff. would be much better!!! but space is a problem even on this bigger model...the axle housing (pipe) is about 2.850" OD

[DADSGARAGE]

Here is a vid of the steering...it is a bit slow but it does seem to have enough torque ( about 4 seconds , full travel, left to right)

[IMG][/IMG]

Thanks for looking....

[RCP57]

Sweet! Now lets see it driving around!
A friend of mine is running a brand new PC5500 face shovel in a BC coal mine. Yesterday he dropped by for a Xmas visit with a present for me...A 400 page operation and maintenance manual for the machine... In 1/10 it will be 35" tall at the house, and about 29" wide with the standard tracks. I'm not sure if I will try to build it but if I did it would be huge.

[Rimrock]

Hi, thats a fine steering setup you've got there) The speed seams more than fast enough i would say. Is that just a standard servo? It seams to follow the stick, is it some special programing that makes the servo travel that many turns in each direction, is it available on several kinds of radios? what about the pot.meter that usually is in the servos, is it removed or?
I've got a Airtronics Sd-10G here, that I really haven't started to get that familiar to yet, but I noticed something in the book about adjusting servos up to 150% travel. On your, you must have but it to several 1000% travel?

[DADSGARAGE]

Originally Posted by RCP57

Sweet! Now lets see it driving around!
A friend of mine is running a brand new PC5500 face shovel in a BC coal mine. Yesterday he dropped by for a Xmas visit with a present for me...A 400 page operation and maintenance manual for the machine... In 1/10 it will be 35" tall at the house, and about 29" wide with the standard tracks. I'm not sure if I will try to build it but if I did it would be huge.

Thanks...( I didn't get a video when I was trying it out the other day, the steering set up does have enough power even with 60lbs of weight in the box, but this is on a flat concrete floor...dirt could be a different story.I just have foam in the rear tires and the 60lbs was really flattening them out but it still seemed to turn OK , but I think the rear tires might be slipping on the rims)

A PC5500 in 1/10 would be awesome!!! If you build it you almost won't need your mini ex. anymore. What about the PC3000, just a bit smaller

http://www.equipmentcentral.com/nort...nt/ACF1184.pdf

[Espeefan]

This is such a cool build to watch, and you are making incredible progress! I'm glad you got some larger photos up. I like your drivetrain and that steering system is pretty cool. I hadn't seen that style servo rack on servocity before. Those guys are constantly coming up with lots of new products. Genius idea on limiting the rear suspension travel, with those new arms and the set screw stops too.

I hope you don't mind, but I'd like to offer a suggestion for your steering knuckle drag links are set up. I've tried an identical system just like that before and I found that you can't get the proper ackerman geometry with it. The inside (of the turn) tire should turn in sharper than the outside. It makes a huge difference in steering. Right now, yours is the opposite. On a heavy truck like this, you might notice an improvement even more so than smaller models. It will 'plow' less in the turns.

It looks you could pretty easily fix the geometry, if you wanted, without changing anything but the way your drag links are bolted to the center steering arm. You just need to swap the right and left side drag links, where they mount to the center arm, with each other. Obviously you can't do that without interference, unless you bolt one drag link on the top of the arm to the top of the steering knuckle, and one on the lower side of both the arm and the knuckle. Picture worth a thousand words....



I don't know if you have the room for changing the drag links to one under, one over, but if you do, give it a shot, and then take your truck for another drive to check how much better it steers. Like I said, I've been there, tried that! Just wanted to share my experiences. I hope you don't mind me suggesting this, and my intention is not to offend you. I can't wait to see this truck all finished up!

[DADSGARAGE]

Originally Posted by Espeefan

This is such a cool build to watch, and you are making incredible progress! I'm glad you got some larger photos up. I like your drivetrain and that steering system is pretty cool. I hadn't seen that style servo rack on servocity before. Those guys are constantly coming up with lots of new products. Genius idea on limiting the rear suspension travel, with those new arms and the set screw stops too.

I hope you don't mind, but I'd like to offer a suggestion for your steering knuckle drag links are set up. I've tried an identical system just like that before and I found that you can't get the proper ackerman geometry with it. The inside (of the turn) tire should turn in sharper than the outside. It makes a huge difference in steering. Right now, yours is the opposite. On a heavy truck like this, you might notice an improvement even more so than smaller models. It will 'plow' less in the turns.

It looks you could pretty easily fix the geometry, if you wanted, without changing anything but the way your drag links are bolted to the center steering arm. You just need to swap the right and left side drag links, where they mount to the center arm, with each other. Obviously you can't do that without interference, unless you bolt one drag link on the top of the arm to the top of the steering knuckle, and one on the lower side of both the arm and the knuckle. Picture worth a thousand words....


I don't know if you have the room for changing the drag links to one under, one over, but if you do, give it a shot, and then take your truck for another drive to check how much better it steers. Like I said, I've been there, tried that! Just wanted to share my experiences. I hope you don't mind me suggesting this, and my intention is not to offend you. I can't wait to see this truck all finished up!

The pics of the steering are deceiving...I didn't have the tie rod lengths set up properly when I took the pics.... one side is longer(oops), which means the steeing arms are not parallel to each other or the frame when pointed straight. I think I know what you mean about the steering geometry when turning the inide tires always have a smaller turning radius which is why the inside front tire need to turn at a sharper angle than the outside tire...this is also the reason why a differential is needed....

Best part of being on here is learning from others...thanks for the input!!

Here is a screen shot of what I used to set up the steering on the truck at full lock....maybe I did this wrong??

[IMG][/IMG]

[RCP57]

Originally Posted by DADSGARAGE

The pics of the steering are deceiving...I didn't have the tie rod lengths set up properly when I took the pics.... one side is longer(oops), which means the steeing arms are not parallel to each other or the frame when pointed straight. I think I know what you mean about the steering geometry when turning the inide tires always have a smaller turning radius which is why the inside front tire need to turn at a sharper angle than the outside tire...this is also the reason why a differential is needed....

Best part of being on here is learning from others...thanks for the input!!

Here is a screen shot of what I used to set up the steering on the truck at full lock....maybe I did this wrong??

[IMG][/IMG]

Oh come on now that's just cheating! What happened to the build it wrong ten times, get p'd off, forget about it and have the solution come to you when you are thinking about something completely different way of building? I need to get more computer savvy!

[DADSGARAGE]

I need all the help I can get.....I still make things wrong ten times...I just make more mistakes faster....

[Espeefan]

Originally Posted by DADSGARAGE

The pics of the steering are deceiving...I didn't have the tie rod lengths set up properly when I took the pics.... one side is longer(oops), which means the steeing arms are not parallel to each other or the frame when pointed straight. I think I know what you mean about the steering geometry when turning the inide tires always have a smaller turning radius which is why the inside front tire need to turn at a sharper angle than the outside tire...this is also the reason why a differential is needed....

Best part of being on here is learning from others...thanks for the input!!

Here is a screen shot of what I used to set up the steering on the truck at full lock....maybe I did this wrong??

That CAD drawing of the truck turning is exactly what you want. Perfect, in fact! I think the problem is your steering drag links do not travel equally, nor in a parallel / linear fashion, if that makes sense. Take a look at this picture.



Because your center steering arm swings in a substantial arc, the drag links do not maintain much parallelism with each other. With the wheels turned to the left, the more steering throw you add, the more out of parallel the right side link becomes. The result is the right link pushes the right knuckle more than the left link pulls the left knuckle. The knuckle on the right is at a greater angle, which is exactly the opposite effect you are after. Does that make sense, or am I barking up the wrong tree?