Yes. The negative to the RX is optional as it is just a ground. This also assumes that your RX is getting power from the ESC for the motor.

Thanks Mike. I tested it and it worked like a charm. Just never thought about it and when I realized that nipping the red from a Y split will do the job, I was like I was today years old. 

Nipped two Y-splits for the BEC connections. The best part about this is that I can set the weight on the back steering to zero to switch to 4x8 or something less than the front steering for less aggressive 8 wheel steering. Not to mentioned change direction will allow it to crab walk as well as trim neutral separately. All done on the radio.

Now I am happy and will bring it out this weekend !

MikeC wrote:

Thanks Mike. I tested it and it worked like a charm. Just never thought about it and when I realized that nipping the red from a Y split will do the job, I was like I was today years old. 

Nipped two Y-splits for the BEC connections. The best part about this is that I can set the weight on the back steering to zero to switch to 4x8 or something less than the front steering for less aggressive 8 wheel steering. Not to mentioned change direction will allow it to crab walk as well as trim neutral separately. All done on the radio.

Now I am happy and will bring it out this weekend !

I will take a Puma for services rendered

LOL.

LOL. After this build I might try to rebuild the PUMA and see if I can get it going again properly. Will swap out for a more powerful servo and see if that helps.

Now the bigger question is, do I dare try this thing in a swimming pool before it gets dirty this weekend.

MikeC wrote:

Now the bigger question is, do I dare try this thing in a swimming pool before it gets dirty this weekend.

Ummm...

Yes. Of course you do!

I would have already built a ramp to the bathtub. Ha haaa. But thats just me.

Opened it up one last time to put in the servo for the opening of the propeller door. Sealed and now ready to swim. Will make a video of it. Fingers crossed.

P.S. Gave up on automating the front splash guard for now. Needs gear work.

Good luck!

Hope it’s a good swimmer

Well it didn't sink.........

But going places, no.......

Hi there. Anyone still on the thread? Any update from Mike the OP.
I just bought this kit. Would love to open a bit more discussion since it is new to me
Thanks

Hey mx,

I still have the beast. Let me know if you need any tips in putting it together. You can see others (Jarlath especially) are more than happy to jump in and help out.

Couple of things right off the top my head that I would do different.

- Make sure you use at least 3S lipo. Started off with 2S lipo and the performance was lacking. 
- If you are going to wade int he water, make sure that the hubcaps are sealed or dry them after you swim with this.
- Would probably spent more time to figure out a servo operating wading flap in the front. I didn't put it in and it is too difficult to do it now afterwards.

MikeC.

MikeC wrote:

Hey mx,

I still have the beast. Let me know if you need any tips in putting it together. You can see others (Jarlath especially) are more than happy to jump in and help out.

Couple of things right off the top my head that I would do different.

- Make sure you use at least 3S lipo. Started off with 2S lipo and the performance was lacking. 
- If you are going to wade int he water, make sure that the hubcaps are sealed or dry them after you swim with this.
- Would probably spent more time to figure out a servo operating wading flap in the front. I didn't put it in and it is too difficult to do it now afterwards.

MikeC.

Thanks man! I didn't even sign for package yet! But don't be afraid to knock it, I won't get sad

So you nailed a couple of my questions. Re front flap, is the kit not set up to do this with a servo? Needs custom fab?

Yes I was probably going to do 3s

The water propulsion seems a bit anemic. Has anyone remedied this? I would guess not much more could be done without risk of prop cavitation?

Also, are the rubber belts sealed off or just gou directly into water and muck?

Thanks!

Front flap is not setup for servo. You needs to figure it out yourself.

Propeller is not powerful enough even with 3S design limitation. It can only pull in so much water and this thing is a monster size wise. I have not try it with 3s in water but the increase speed from the wheels would help. You need to wire/program it so that they will run at the same time when you are wading.
The suspension is sealed off from the rubber drive but the rubber drive is also sealed off from the main compartment. So even if water gets into the rubber drive compartment it is still okay. Nothing will rust there.

MikeC wrote:

You can see others (Jarlath especially) are more than happy to jump in and help out.

HEY! I resemble that remark! LOL.

I do like your BTR. Engineering on it is better than on the the Puma (still trying to find spare bevel gears...).

I thought those belts spun surrounded by water. But I guess that whole area is sealed and an air pocket that probably helps buoyancy?
Are all the tires sealed to help buoyancy as well?

No the belt compartment is sealed. The tires are sealed but not the hub caps. Mine got all rusted out because I didn't clean it out after the swim. I will at some point clean them out and then try to seal the hubcaps as well.

Banned


Does it look like this style of propulsion could be fitted without too much work?

Well looks like I am not allowed to post a link because new

Can you post a picture ?

MikeC wrote:

Can you post a picture ?

Hmmm, well, I guess it was nothing special. Just a typical boat propulsion similar to this amphibian one.
The one on this kit seems more compact. Obviously anything can be modified, but I don't want to hack this new kit up either.

Probably better to maximize potential of the system in this kit
So you have not tried water with 3s? This could be a significant boost, no?
Also, are you a boat guy? When the time comes, I wonder if an RC boat forum can give advice to maximize design?
Do you have a sense it is more like a flow restriction? Or a prop and power restriction?

Maybe there are some subtle flow changes that can be ported in and a prop change all combined with 3s that would make significant improvement?

I suppose some things could be tested in a tub?

Did you have unfinished thoughts on the water mods that you just sort of lost interest or didn't get to that you might share?

Did the steering even seem to work? The rudders could maybe be extended in either direction a few mm?

It's hard to tell in videos, could this thing barely make it across small body of smooth water?

Thanks!
Ups is supposed to be delivering today!

Other thoughts I had. Were you happy with 2s on land?
I want to keep more of 2s if possible in order to get extended run time. 3s will start to limit mAh capacity just by sheer limited space and weight.
So, it would seem brushless motor upgrade with appropriate Kv would be better than stock even on 2s.
Thoughts?

If you primary goal is for this thing to swim then you probably got the wrong kit. This sucker is heavy as hell and I don't know what you mean by flow changes ? It is a freaking 8x8 so there is lots happening down there.

The steering is okay. I am not  fan of crab crawl (ie. 8 wheel steering) so I set it up so that I can turn off the steering of the rear 4 wheels. I didn't not hook up the propeller with the wheels, so I did not try wading with the wheels rotating as well either with 2S or 3S. The performance is strictly on land. If you want the thing to move like their promo video and be able to do donuts and kick up dirt you need 3S. Just buy one strictly for this sucker. There is a huge battery compartment in the back deck you just can't get too thick ones. 

I put it in my condo pool which is about 20m long. My worry was actually this thing sinking on me but then I start praying to Archimede and the old Italian came thru..........

My apologies, I keep having thoughts. Do the tires always spin in water? Or is there a hard switch to prop? I think I could setup either way or maybe a choice with remote switch

Do wheels spin in real life full size?

For purposes of RC, if wheels are always spinning....do they play role in propulsion? If the wheels do, it seems like you could hide a curved tread on the inner tire sidewalls to act as a paddle? I don't have ways to make something like this, but it seems you could build upper an inner tread out of silicone type glue.

The propeller has its own ESC and motor so it is completely separate. However there is nothing stopping you from running the wheels while your propeller is going, or even steering with the wheels also. My propeller is on a knob so I can crank it and just leave it running even on dry land. I did link the rudder to the front steering.

I believe in real life the wheels does spin in the water to help with the propulsion. 

You need to stop obsessing about running this thing as a boat. It is not.