the r& d on our high speed drums is over.....some findings

Many of you have been following the development of our somewhat fast spinning drums, and I am confident in saying that our findings seem to be accurate. Some of the info may seem obvious, but I feel that it needs to be included in order to put things in context.

Please feel free to disagree, in that this is not about mine is better than yours, simply a sharing of knowledge and info on a subject that I believe we have contributed to as much or more than any others

so here goes...

1) in a weapon to weapon head to head battle, tip speed is the key. this does not necesarily mean that tip speed will cause an opponent to hit the roof, but the faster tip seems to always get the better of the encounter

this seems to apply both to vertical vs vertical and vertical vs horizontal

2) if tip speeds are equal , then the weapon with more energy will probably prevail....I 've noticed this when we slow our drums down against weapons carrying more energy at speed.

How do our drums compare?

1) we've gone with lighter faster drums than most . this is a compromise that we will live with. the good is that when at speed, we create as much or more energy than most and with the high tip speed, this is good when facing other spinners, as long as we can keep the speed up there. the only way we can get a to the roof hit, is if drive speeds of both or either bot is high.

Little Sting is kind of amazing, in that even against Ripto 2.0 and repeated full force hits when ripto was inverted and the weapons were spinning in opposite directions, the little 20mm motor didn't miss a beat. nor did it slow down vs the horizontals..why? at speed we are carryng a lot of energy.

when 2 weapons spinning in the same direction meet, the combined energy cancels and the slight extra speed is the big factor..example... jamo vs sting, ripto 2 (when right side up) vs sting etc

2) we've been thru the gamit of materials, drum shapes, etc. and here are the findings

a) especially with a single tooth or staggered tooth drum, rigidity has to be far beyond the norm. more than twice that of a 2 or more bladed drum.

On a side note...at moto, I noticed, especially in the hobbies, that you HAVE to have a totally steel weapon....so, best to go with a steel beater, steel tube or as in our case , machined from a solid s7 round.

3) it would seem that a large diameter high mounted fast spinning weapon would be ideal....this is the case, except that it can take away from the handling of the bot, and inverted operation can be a problem. so you better be a better driver...disc type weapons seem to be the worse handling.

I don't drive very well at this point ( duh..never had time to practice much) but I have had a few moments when the lack of big gyro and better mobility of our drumbots has been a factor. in our favor...

4) the bar has been raised....weapons are getting more powerful and unless you can drive really well, expect to get crushed by the higher energy ALL steel weaponed bots.

5) How well things go also greatly depends on the rigidity of your bot, from frame to weapon tip and everything in between

the moto videos show that literally every other bot was driven by a much better driver than me, yet the rigidity of our bots prevailed in many cases.

with a weight limit imposed, an ALL weapon on wheels bot will probably blow up due to its own energy or the combined energies..exception to this may be the fbs.

Driving a high tip speed bot

1) against wedges , etc. the weapon needs to be slowed down greatly or drive speed increased accordingly to get any bite..and then you lose the high energy if your weapon is light.

2) against other spinners..... keep it spinning to the moon in head ons...better to grind and then possibly get a bite in and flip them, than to be on the receiving end.

If you can drive and manouver to a side or non rotating member, slow it down and go for the roof. The reversible esc's with braking are ideal for this.

Nothing is perfect, everything is a compromise, but I feel that enough real world r & d has been done to prove that high tip speed weapons can be very effective.

About rigidity and problems with high rpm weapons

A larger diameter, heavy, high tip speed weapon is much easier to design and maintain. Bushings and needle bearings have a lot more contact and support than ball bearings.....to get extremely high rpm's, ball bearings are about the only choice, but they are NO where near as rigid, and steps have to be taken to increase rigidity and durability of the system as a whole.

Many have seen the insides of Stings drum, especialy the one that peeled like a banana. Obvious is the dual bearing per side arrangement, but not so obvious is how things work to lower amperage draw and heat.

I'll go into full disclosure details on this after this years nationals....but I will say this much..I've managed to cut amperage draw almost in half and even at 40 and 50k rpm's the only heat is from belt friction. withour these mods, the 20mm motor in Sting would overload immediately.

So, if you can get to that point while maintaining rigidity, you're pretty much there.

I can say with confidence that sting is no longer a 1 hit wonder...and it's been a long road

Here are some pics of the drums after moto

Sting's drum



It Stings drum

Very well written! I agree on all topics discussed and it might even be worth saving as some kind of documentary.

and that's the drum AFTER Moto?! ShamWOW! It looks brand new!

rjw wrote:

The reversible esc's with braking are ideal for this.

ya i didn't realise you had one in sting during our fight, when i fliped you i wanted to go right for the weapon to weapon contact and send you soaring, then i got fliped again and stranded =P

Koolaid64 wrote:

rjw wrote:

The reversible esc's with braking are ideal for this.

ya i didn't realise you had one in sting during our fight, when i fliped you i wanted to go right for the weapon to weapon contact and send you soaring, then i got fliped again and stranded =P

I consider myself very lucky to get out of that one with a w..

I'm gonna have to get some serious driving practice going if I want to stay alive in the future...

It was like playing video gameswith my son years back....even when he was 8 or 10, he kicked my butt totally.

I tried to get will, Jamo and Josh to drive little Sting, but I don't think anyone likes me...

Jamo_G wrote:

Very well written! I agree on all topics discussed and it might even be worth saving as some kind of documentary.

and that's the drum AFTER Moto?! ShamWOW! it looks brand new!

Hey Jamo

If you think its worth putting up on the other forum, feel free to copy and paste...pics and all

I'm kind of trying to make this forum my home base...mayb help Dan bring in some new blood, in that more people are starting to notice that we do exist.

Thanks

hmmm, i either have people screwing with my stuff, or someone is a hacker. I did not write shamWOW in my post...

Jamo_G wrote:

hmmm, i either have people screwing with my stuff, or someone is a hacker. I did not write shamWOW in my post...

wierd....I once posted a comment and it ended up in someone else's post?????

this is the internet twilight zone....

Jamo_G wrote:

hmmm, i either have people screwing with my stuff, or someone is a hacker. I did not write shamWOW in my post...

Well, it could be that you just forgot what is auto-replaced by shamWOW...

lol yeah because nola and other highly regarded officials are on the forums so the language is monitored

haha good point. I thought about that because I saw shamWOW on another thread.

Anyway RW, I might try going up to Moto next year. If you are going, I wouldnt mind taking the sticks for a few matches.

We like you! I promise! =D

Jamo_G wrote:

haha good point. I thought about that because I saw shamWOW on another thread.

Anyway RW, I might try going up to Moto next year. If you are going, I wouldnt mind taking the sticks for a few matches.

We like you! I promise! =D

We should talk

I either have to get some serious practice in, or find a NEW team member that can do the driving.

If you're interested, let's talk......maybe we could join forces and really put on a show....Doesn't have to be just mlec's or my ideas...it's all about r&d and moving the sport forwardon the the techno end of things. I'm sure that I could contribute somewhat to our bots as well