Limitless Castle 1721 records?

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I was curious as well. I noticed Castle specs these for “4s minimum” but I saw guys running 3s on their speed runners, @Diem Turner (122mph) and @phildogg (127mph) did in the 3s challenge, among others. In the 4s challenge @slow rc mike did 155. I haven’t checked the PB thread, but there must be some speeds listed there for the 1721’s on 6-8s?
 
I was curious as well. I noticed Castle specs these for “4s minimum” but I saw guys running 3s on their speed runners, @Diem Turner (122mph) and @phildogg (127mph) did in the 3s challenge, among others. In the 4s challenge @slow rc mike did 155. I haven’t checked the PB thread, but there must be some speeds listed there for the 1721’s on 6-8s?
Yeah, they spec it at 4S minimum, but in practice it's shown itself to be a competent powerplant even on 3S. Part of me is curious to see if it can deliver anything useable on 2S...maybe I'll have a go when the weather breaks in 7 or 8 months.

Slow RC Mike pulled 137mph on 3S with the 1721 in a VTE. He's still the 3S leader...and not by a slim margin. I do wonder if the depths of the 1721 have been plumbed on 4S or if there are a few more mph to be had. I've seen people run high 160s to low 170s on 6S and the fastest I've seen (yes, I know his runway, yadda and etc.) was Raz who ran a blistering 192mph on a single 1721 when it first came out on 8S parallel with two gigantic (what I presume were) 8S SRD V2 prototypes. However, knowing what we know, it's probably realistic to put the 1721 in the mid 180s at the top end assuming that batteries with sufficient cojones are employed.
 
Yeah, they spec it at 4S minimum, but in practice it's shown itself to be a competent powerplant even on 3S. Part of me is curious to see if it can deliver anything useable on 2S...maybe I'll have a go when the weather breaks in 7 or 8 months.
What would the downside of running “ under spec” voltage, i.e. 3s or 2s be? It would have much higher amp spikes, right? Or am I not understanding this?
 
What would the downside of running “ under spec” voltage, i.e. 3s or 2s be? It would have much higher amp spikes, right? Or am I not understanding this?
Amps will be high when running low voltage, but that's nothing unique to the 1721 or even to low voltage, honestly. I've seen 600A+ on every voltage from 3S-8S, it's all just a matter of how hard you push and if you can find the right combination of motor, gearing and voltage. You're going to run into that with, dare I say, all motors (without having tested this theory with all or even many motors...I think high current is just a natural bi-product of high load speed running, irrespective of what voltage you're running at) at some voltage.

I leave the caveat of "all motors" at "some voltage" open because, so far, the highest current I've pulled on fresh 3S packs with the 1721 was somewhere around 420-430A on my 122mph pass. Once the voltage of the packs starts dropping, the amps will naturally go up to meet the power demands the motor (Watts = Voltage x Amps) is putting on the ESC. Interestingly I've never had a second run on a set of batteries go faster than the first run, though I've seen numerous people do this. This is why I never make a second pass if the first one is a "full pull" with three seconds of WOT. I don't understand how a second pass could conceivably be faster and, as I said, I've never experienced this myself even though I've seen or heard of it happening. I'm not disputing it happening to others, I'm just saying it doesn't make sense to me how packs with voltage that must be lower on voltage than on the first pass could or can be faster. But sometimes, they are. 🤷‍♂️
 
Amps will be high when running low voltage, but that's nothing unique to the 1721 or even to low voltage, honestly. I've seen 600A+ on every voltage from 3S-8S, it's all just a matter of how hard you push and if you can find the right combination of motor, gearing and voltage. You're going to run into that with, dare I say, all motors (without having tested this theory with all or even many motors...I think high current is just a natural bi-product of high load speed running, irrespective of what voltage you're running at) at some voltage.

I leave the caveat of "all motors" at "some voltage" open because, so far, the highest current I've pulled on fresh 3S packs with the 1721 was somewhere around 420-430A on my 122mph pass. Once the voltage of the packs starts dropping, the amps will naturally go up to meet the power demands the motor (Watts = Voltage x Amps) is putting on the ESC. Interestingly I've never had a second run on a set of batteries go faster than the first run, though I've seen numerous people do this. This is why I never make a second pass if the first one is a "full pull" with three seconds of WOT. I don't understand how a second pass could conceivably be faster and, as I said, I've never experienced this myself even though I've seen or heard of it happening. I'm not disputing it happening to others, I'm just saying it doesn't make sense to me how packs with voltage that must be lower on voltage than on the first pass could or can be faster. But sometimes, they are. 🤷‍♂️
Thank you! That’s what my understanding was but I try not to rely on that, choosing instead to embrace the whole “don’t believe everything you think” adage. I’m definitely still learning.
And also, I’ve been meaning to thank you sincerely for your use of the word irrespective. Every time I hear someone say “irregardless” I want to go on a three-state killing spree.
 
Thank you! That’s what my understanding was but I try not to rely on that, choosing instead to embrace the whole “don’t believe everything you think” adage. I’m definitely still learning.
And also, I’ve been meaning to thank you sincerely for your use of the word irrespective. Every time I hear someone say “irregardless” I want to go on a three-state killing spree.
lol...irregardless is an abomination of a word. There are a number of linguistic abortions that have made their way into common parlance that make me want to puke into my suit every time I hear them, but this one is particularly obscene. Love ya bro :LOL:
 
Thank you! That’s what my understanding was but I try not to rely on that, choosing instead to embrace the whole “don’t believe everything you think” adage. I’m definitely still learning.
And also, I’ve been meaning to thank you sincerely for your use of the word irrespective. Every time I hear someone say “irregardless” I want to go on a three-state killing spree.

Do it!

mean girls gretchen weiners GIF
 
I was curious as well. I noticed Castle specs these for “4s minimum” but I saw guys running 3s on their speed runners, @Diem Turner (122mph) and @phildogg (127mph) did in the 3s challenge, among others. In the 4s challenge @slow rc mike did 155. I haven’t checked the PB thread, but there must be some speeds listed there for the 1721’s on 6-8s?
Good ole yours truly ran 99 on 2s and 125 on 3s with one. Gonna try again tomorrow ro break 100 on 2s
 
I don't understand how a second pass could conceivably be faster and, as I said, I've never experienced this myself even though I've seen or heard of it happening
I'd be willing to bet it's from the lipos being cold on the first run.
 
Yeah, they spec it at 4S minimum, but in practice it's shown itself to be a competent powerplant even on 3S. Part of me is curious to see if it can deliver anything useable on 2S...maybe I'll have a go when the weather breaks in 7 or 8 months.

Slow RC Mike pulled 137mph on 3S with the 1721 in a VTE. He's still the 3S leader...and not by a slim margin. I do wonder if the depths of the 1721 have been plumbed on 4S or if there are a few more mph to be had. I've seen people run high 160s to low 170s on 6S and the fastest I've seen (yes, I know his runway, yadda and etc.) was Raz who ran a blistering 192mph on a single 1721 when it first came out on 8S parallel with two gigantic (what I presume were) 8S SRD V2 prototypes. However, knowing what we know, it's probably realistic to put the 1721 in the mid 180s at the top end assuming that batteries with sufficient cojones are employed.
I ran it on 2s
 
I ran it on 2s
Nice! Ok, this just convinced me that I can speed run almost all winter long. 2S is the key. My VTE handles beautifully even on soaked roads and the 2S speed envelope should be perfectly manageable, even in the wet. Time to get wrenching.

Oh and, lol...I swear your weather looks like it comes straight out of a computer simulation or holodeck. I lived in Walnut Creek, CA from '85-'90 so I'm all too familiar with it. It's always striking as it's not just the deep blue sky and the lone cloud that was picked out of an iStock catalogue. Yes, the camera has a good lens which accentuates the image, but the air is always so clean and transparent. I feel like I can see further into the distance on your videos than pretty much any other RC content I watch. The video quality is excellent and the environment just makes everything look great is what I'm saying. :)
 
Nice! Ok, this just convinced me that I can speed run almost all winter long. 2S is the key. My VTE handles beautifully even on soaked roads and the 2S speed envelope should be perfectly manageable, even in the wet. Time to get wrenching.

Oh and, lol...I swear your weather looks like it comes straight out of a computer simulation or holodeck. I lived in Walnut Creek, CA from '85-'90 so I'm all too familiar with it. It's always striking as it's not just the deep blue sky and the lone cloud that was picked out of an iStock catalogue. Yes, the camera has a good lens which accentuates the image, but the air is always so clean and transparent. I feel like I can see further into the distance on your videos than pretty much any other RC content I watch. The video quality is excellent and the environment just makes everything look great is what I'm saying. :)
Thank you I appreciate that buddy but actually the air quality here is horrible like as in the air quality index but I know what you mean
 
Thank you I appreciate that buddy but actually the air quality here is horrible like as in the air quality index but I know what you mean
Well it sure looks pretty from Germany's winter vantage point. Dents, warts and all. Then how about optical qualities? That takes the visual into account without downplaying the pollution...at least not overtly. :LOL:
 
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