R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric Off-Road

    Hide Wikipost
Old 07-29-2016, 08:27 AM   -   Wikipost
R/C Tech Forums Thread Wiki: New Schumacher KF2
Please read: This is a community-maintained wiki post containing the most important information from this thread. You may edit the Wiki once you have been a member for 90 days and have made 90 posts.
 
Last edit by: MelKF2
Welcome to the KF2 Wiki!

Please feel free to add any Tips, Tricks, or anything that would be beneficial to the KF2 Family

Introduction and Pictures Introduction and Pictures

ElectronicsSetupElectronicsSetups

Setup SheetsSetup Sheets

EmulsionShocksEmulsion Shocks

Tony Newland Gear Diff BuildTony Newland Gear Diff Build

Suggested Gearing

6.5
7.5
8.5
9.5
10.5
13.5
17.5 I ran 69/31 at SRS Scottsdale Arizona and 72/30 at MHOR Aurora Co and Full Throttle ALB, NM RCM lockout worked excellent!


MIP pucks excellent upgrade! The new RCM lockout is an excellent piece as well! These options will greatly reduce weight throughout the drive line!

Print Wikipost

Like Tree5Likes
Reply
 
Thread Tools Search this Thread
Old 08-01-2015, 11:52 AM   #376
Tech Adept
 
Mustrum's Avatar
 
Join Date: Jul 2013
Posts: 105
Default

Tires are proline holeshot.
Mustrum is offline   Reply With Quote
Old 08-01-2015, 05:59 PM   #377
Tech Regular
R/C Tech Elite Subscriber
 
Join Date: Jul 2015
Location: Pueblo, Co
Posts: 283
Smile KF2MM

Quote:
Originally Posted by motorcitymatt View Post
That's really interesting. A whole second per lap is a lot at that level. Now I'm even more eager to try out this MM kit seeing as how it was outperforming the KR on a surface typically judged as more suitable for the KR. The video I watched showed most cars running small pin tires in the rear and ribbed tires in the front. Is that correct?

If you would be willing to share his KF setup with us here or email it to me personally that would be really helpful. But I understand if you aren't comfortable with that or would want to ask his permission first.

I think the race starts Monday if I remember correctly? I'd love to see Michal (or anyone else for that matter!) beat Lee Martin....
Matt I really Enjoy reading our threads very knowledgeable! and I agree about Michal beating Martin, he did it a couple of times this year! There will be more.
MelKF2 is offline   Reply With Quote
Old 08-01-2015, 06:24 PM   #378
Tech Adept
 
motorcitymatt's Avatar
 
Join Date: Mar 2015
Location: Royal Oak, MI
Posts: 194
Default

While waiting for the MM kit to arrive I decided to put the car on the scales using the existing layout (low grip configuration) and compare it to the MM layout (using the Facebook photo of Orlowski's car as a reference). Not that it so much matters because I am just looking at deltas here but I weighed the car with the (now obsolete) CF chassis, rear and front arms reversed with rear hubs all the way forward and no tires. I also removed the aluminum side stiffeners as they do not allow for the shorty lipo to fit in between them.

The results were surprising to say the least. This is because the F/R weight distribution with both of the layouts is almost identical! About 39.5% / 60.5% front / rear. My speculations about what the effect on the weight distribution would be were completely and utterly wrong.

A few posts back someone put Maizer's car on the scales with a similar modification to this factory kit with respect to layout. The results were similar to what I found here. I should have remembered.

This of course means that Schumacher is relying on the motor's dynamic forces under acceleration to manipulate the chassis to put more weight on the rear. Assuming the effect is substantial enough to meet our needs in terms of forward bite then they have done something quite clever. We will have less on-power steering in exchange for that forward traction but the overall feel of the car around the track and the way it handles at large will stay mostly the same. Well done.

Another thing I noticed while doing the measurements was that the battery is now sitting almost perfectly longitudinally centered on the car's center of mass. I replaced the standard shorty lipo weighing 210g with one of my LRP super shorty packs, which only weighs 138g. On the scales the F/R weight distribution of the car once again did not change but the car just lost 68g of weight.

Now I don't know if the engineers at Schumacher had intentionally designed the car with this MM configuration up their sleeve in case they wanted to add some rear grip in the future if the team/customers decided they really needed it or if this just happens to be a coincidence that they discovered while testing the idea. Either case is really interesting for different reasons.

And for those who may be considering running the MM kit without the CF top brace to save weight or add flex I really, really would recommend not doing so. The engineers are clearly relying on the chassis to transmit the forces generated by the motor under acceleration to improve rear grip so removing any of the rigidity will compromise the design. And now with the aluminum side stiffeners gone removing the top brace will probably hurt a lot more than it might help in other areas.
__________________
Schumacher Cougar KC, KF2 SE
RC Clubhouse in Warren, MI
DiscountRCStore.com (The best online hobby shop)

Last edited by motorcitymatt; 08-01-2015 at 09:37 PM.
motorcitymatt is offline   Reply With Quote
Old 08-01-2015, 06:31 PM   #379
Tech Adept
 
motorcitymatt's Avatar
 
Join Date: Mar 2015
Location: Royal Oak, MI
Posts: 194
Default

Quote:
Originally Posted by MelKF2 View Post
...and I agree about Michal beating Martin, he did it a couple of times this year! There will be more.
I would prefer one of those wins to be at Yatabe Arena in October. I just love the idea of a 14/15 year old kid being the world's best at anything, never mind R/C racing. It has that David vs Goliath flavor to it.....
__________________
Schumacher Cougar KC, KF2 SE
RC Clubhouse in Warren, MI
DiscountRCStore.com (The best online hobby shop)
motorcitymatt is offline   Reply With Quote
Old 08-01-2015, 06:45 PM   #380
Tech Champion
 
hanulec's Avatar
R/C Tech Elite Subscriber
 
Join Date: Sep 2007
Location: @ the post office
Posts: 8,452
Trader Rating: 27 (100%+)
Default

I don't think the top deck is needed. I'm holding off on the mm "kit" and will try adding much more weight to the battery area along with the lrp super shorty. My car with std shorty is 1504g. I wanna try adding 30g as rear as possible first.
__________________
FJ / ROAR #2-122945 / MaxRotation FPV Drone Racing / Shop@ Awesomatix USA / Wild Turbo Fan / Mon-Tech Racing / RocheRC USA / Side Piece /
LRP / John's BSR Tires / TeamEAM / TQ Wire / R1 / Team Scream / PCR / MIX
RacerLog wiki Awesomatix A700 / 2wd offroad 4 life
hanulec is offline   Reply With Quote
Old 08-02-2015, 12:51 PM   #381
Tech Regular
 
Jpdanger's Avatar
 
Join Date: Feb 2015
Location: TRCR
Posts: 386
Default

Quote:
Originally Posted by motorcitymatt View Post
While waiting for the MM kit to arrive I decided to put the car on the scales using the existing layout (low grip configuration) and compare it to the MM layout (using the Facebook photo of Orlowski's car as a reference). Not that it so much matters because I am just looking at deltas here but I weighed the car with the (now obsolete) CF chassis, rear and front arms reversed with rear hubs all the way forward and no tires. I also removed the aluminum side stiffeners as they do not allow for the shorty lipo to fit in between them.

The results were surprising to say the least. This is because the F/R weight distribution with both of the layouts is almost identical! About 39.5% / 60.5% front / rear. My speculations about what the effect on the weight distribution would be were completely and utterly wrong.
Could you add wheels and tires to the equation? Rear tires weigh more than fronts, so that is going to add weight to the rear end.

I guess you can't argue with data from the scales, but I have a hard time believing that swapping the motor position with the battery doesn't increase the rearward weight. Your earlier post weighing the motor assembly at 290g is roughly 80g more than a standard shorty battery. Do the hold down straps, lipo stop, and front brace equal the 80g difference between? You're also subtracting the front stiffeners.
__________________
I buy RC cars for my kids like a man buys a bowling ball with his name on it for his wife.

"What I say makes sense in my head. Once it comes out of my mouth it's for you to figure out." -me
Jpdanger is offline   Reply With Quote
Old 08-02-2015, 02:44 PM   #382
Tech Addict
 
Join Date: Nov 2005
Location: Fly-over Country
Posts: 567
Trader Rating: 1 (100%+)
Default

Scales can only give you static weight in one configuration... complete stand-still at ride height. The Inertial qualities of battery and motor as well as there positions will have significant effects on the dynamics of the vehicle on the track.

For me it is hard to rule out a design based on scale readings alone. Scales are not the end-all be-all.
Banshee8530 is offline   Reply With Quote
Old 08-02-2015, 07:16 PM   #383
Tech Regular
R/C Tech Elite Subscriber
 
Join Date: Jul 2015
Location: Pueblo, Co
Posts: 283
Default Maizer

Quote:
Originally Posted by motorcitymatt View Post
While waiting for the MM kit to arrive I decided to put the car on the scales using the existing layout (low grip configuration) and compare it to the MM layout (using the Facebook photo of Orlowski's car as a reference). Not that it so much matters because I am just looking at deltas here but I weighed the car with the (now obsolete) CF chassis, rear and front arms reversed with rear hubs all the way forward and no tires. I also removed the aluminum side stiffeners as they do not allow for the shorty lipo to fit in between them.

The results were surprising to say the least. This is because the F/R weight distribution with both of the layouts is almost identical! About 39.5% / 60.5% front / rear. My speculations about what the effect on the weight distribution would be were completely and utterly wrong.

A few posts back someone put Maizer's car on the scales with a similar modification to this factory kit with respect to layout. The results were similar to what I found here. I should have remembered.

This of course means that Schumacher is relying on the motor's dynamic forces under acceleration to manipulate the chassis to put more weight on the rear. Assuming the effect is substantial enough to meet our needs in terms of forward bite then they have done something quite clever. We will have less on-power steering in exchange for that forward traction but the overall feel of the car around the track and the way it handles at large will stay mostly the same. Well done.

Another thing I noticed while doing the measurements was that the battery is now sitting almost perfectly longitudinally centered on the car's center of mass. I replaced the standard shorty lipo weighing 210g with one of my LRP super shorty packs, which only weighs 138g. On the scales the F/R weight distribution of the car once again did not change but the car just lost 68g of weight.

Now I don't know if the engineers at Schumacher had intentionally designed the car with this MM configuration up their sleeve in case they wanted to add some rear grip in the future if the team/customers decided they really needed it or if this just happens to be a coincidence that they discovered while testing the idea. Either case is really interesting for different reasons.

And for those who may be considering running the MM kit without the CF top brace to save weight or add flex I really, really would recommend not doing so. The engineers are clearly relying on the chassis to transmit the forces generated by the motor under acceleration to improve rear grip so removing any of the rigidity will compromise the design. And now with the aluminum side stiffeners gone removing the top brace will probably hurt a lot more than it might help in other areas.
I also scaled (SkyRC) out my KF2 with Maizer's set up 39/61, 1518 grs. Are numbers are close! I also found out that when changing my rear arm back to kit I lost 1% rear to 40/60 and then from short wheel base to long or med I lost another 1% 41/59. Wonder if the MM will be the same or will there be more weight transfer to the rear?
MelKF2 is offline   Reply With Quote
Old 08-02-2015, 08:28 PM   #384
Tech Champion
 
thecman26's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jul 2006
Location: South Central Kansas
Posts: 7,685
Trader Rating: 98 (100%+)
Default

I am gonna have to keep my eyes on this thread. Been really considering the Yokomo YZ2 for a mild mod (9.5t) on indoor med-high bite smooth/bumpy clay track.

How would folks say this would compare to the YZ2?
__________________
Chris Keen: Viola, Kansas
Kyosho RZ6, TLR 22 3.0, TLR 4.0 SR (soon),& 22T 3.0
"I'm too drunk to taste this chicken!", Col. Sanders
thecman26 is offline   Reply With Quote
Old 08-02-2015, 08:55 PM   #385
Tech Adept
 
motorcitymatt's Avatar
 
Join Date: Mar 2015
Location: Royal Oak, MI
Posts: 194
Default

I'll be able to answer that question for you soon. I hope to have my MM-converted KF2 on the track this week for our Friday night club race at the latest. The owner of our track started racing with a YZ-2 over his RB6 so maybe I can get him to take a few laps with my car and vice versa and we can compare notes.

With the MM conversion on the KF2 the cars look fairly similar in terms of layout with the motor/gearbox a little further back on the Yokomo. I believe the YZ-2 is a four gear transmission so the forces the motor puts on the chassis during acceleration should be similar as well.
__________________
Schumacher Cougar KC, KF2 SE
RC Clubhouse in Warren, MI
DiscountRCStore.com (The best online hobby shop)
motorcitymatt is offline   Reply With Quote
Old 08-02-2015, 09:06 PM   #386
Tech Adept
 
motorcitymatt's Avatar
 
Join Date: Mar 2015
Location: Royal Oak, MI
Posts: 194
Default

I found some more nice pictures of the KF2 with the MM conversion. These are Ben Jemison's car he is going to run at the Euro's this week.

https://www.facebook.com/41103186907...53621421486013

https://www.facebook.com/41103186907...53621404819348

Take a look at the rear toe-in blocks. Are those brass? All the ones I have seen are black anodized aluminum.
__________________
Schumacher Cougar KC, KF2 SE
RC Clubhouse in Warren, MI
DiscountRCStore.com (The best online hobby shop)

Last edited by motorcitymatt; 08-02-2015 at 09:32 PM.
motorcitymatt is offline   Reply With Quote
Old 08-02-2015, 09:55 PM   #387
Tech Regular
 
Jpdanger's Avatar
 
Join Date: Feb 2015
Location: TRCR
Posts: 386
Default

Quote:
Originally Posted by motorcitymatt View Post
I found some more nice pictures of the KF2 with the MM conversion. These are Ben Jemison's car he is going to run at the Euro's this week.

https://www.facebook.com/41103186907...53621421486013

https://www.facebook.com/41103186907...53621404819348

Take a look at the rear toe-in blocks. Are those brass? All the ones I have seen are black anodized aluminum.
They don't look like they are brass. Maybe a non anodized aluminum or polished lead or steel? The shock collars look abnormally large. Titanium screws? Not running the reversed arms?
__________________
I buy RC cars for my kids like a man buys a bowling ball with his name on it for his wife.

"What I say makes sense in my head. Once it comes out of my mouth it's for you to figure out." -me
Jpdanger is offline   Reply With Quote
Old 08-02-2015, 10:58 PM   #388
Tech Adept
 
Mustrum's Avatar
 
Join Date: Jul 2013
Posts: 105
Default

Quote:
Originally Posted by Jpdanger View Post
They don't look like they are brass. Maybe a non anodized aluminum or polished lead or steel? The shock collars look abnormally large. Titanium screws? Not running the reversed arms?
Small bore shocks!
Mustrum is offline   Reply With Quote
Old 08-03-2015, 01:12 AM   #389
Tech Regular
 
Gayosaka's Avatar
 
Join Date: Dec 2005
Location: France, near Paris
Posts: 309
Default

Quote:
Originally Posted by Jpdanger View Post
They don't look like they are brass. Maybe a non anodized aluminum or polished lead or steel?
Those stock parts are sold in the old purple ano, so my guess is he polished them to get the bare aluminium look. I did the same thing on mine, a few minutes on owen cleaner did the trick.

Yes he is running small bore, Schumacher re-released them. They say it feels better on low-grip tracks.
__________________
RedWorkShop RZ6R / Kyosho RB6.6 / Kyosho ZX6.6 / Nosram power / Some MiniZ
www.rustidesign.com - Awesome custom stickers and cool stuff
Gayosaka is offline   Reply With Quote
Old 08-03-2015, 01:15 AM   #390
Tech Regular
 
Gayosaka's Avatar
 
Join Date: Dec 2005
Location: France, near Paris
Posts: 309
Default

Quote:
Originally Posted by Jpdanger View Post
Could you add wheels and tires to the equation? Rear tires weigh more than fronts, so that is going to add weight to the rear end.
You shouldn't be using tires to get the weight ratio. Wheels are unsprung weight.
__________________
RedWorkShop RZ6R / Kyosho RB6.6 / Kyosho ZX6.6 / Nosram power / Some MiniZ
www.rustidesign.com - Awesome custom stickers and cool stuff
Gayosaka is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 11:27 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net