John Stranahan

iTrader: (27)

Hand Made Chassis
I found a supplier of "quasi grade" grapite sheet to the RC Hobbyist.

http://www.penguinrc.com/ordering/ordercomplete.html

I ordered up a 14 x 9 inch 2.5 mm sheet which should do two chassis and maybe a pod bottom plate or two and one 7x9 sheet to make thinner 2.0 mm parts. I plan to cut the chassis by hand with the Dremmel. I will tell you how it comes out.
John

McPappy Dyno
Note the McPappy dyno is actually a production unit and can be purchased now.
http://www.mcpappyracing.com/dyno.php

tudor_47

John, I have sent you an email

SKJ

iTrader: (20)

John

I forgot about Penguin, I need some graphite for a front bumper and they are 10minutes from my house.

FYI Penguin also cuts graphite also. Anyway that is what I heard.

Have you heard of www.emachineshop.com ? They do cut graphite.

I will probably be using them in the near future for a part.

Conrad

iTrader: (3)

Sorry to hear that John, at least you have a nice shiny mustang to keep you smiling The UK misses out on all the good things....again!

John Stranahan

iTrader: (27)

Thanks for the posts guys.

Here is a pic of a Scimitar style rear upper shock mount on a JS Pro 200 BA. This car is going to the Virgin Islands in the morning. The advantages over the previous mount are fewer parts. Less weight, adjustable upper ball angle to make small changes in shock angle. It also uses the long rear side plate to make small adjustments in lateral position of the body.
john

John Stranahan

iTrader: (27)

Track Session Wide Pan
I had a nice session today. I still remember how to drive a little bit.
Our straight has increased in size by removing an early chicane on it. We are probably hiitting near 70 now before the sweeper. Grip was medium. I required a slight tap of 35% brakes to stay planted in the sweeper.

gear play
on the most powerful wide pan car setups, you need to adjust the gear lash while you pull back on the wheel to remove the right rear bearing play. This will keep you from stripping gears on brakes and on hard throttle. You still need a little play, but with the wheel pulled back.

the session ended with the back of the motor coming off and pulling out my motor sensor wires. A little high temp lock tite on the LRP X12 screw might be in order.

My thunder Power batteries were still in good shape and rocketed down the straight.

john

John Stranahan

iTrader: (27)

Track Session Wide Pan
I had a good session today. I made some adjustments to the car to adapt it better to the new layout. The straight is longer. The very technical chicanes are gone or reduced in difficulty.

The car reaches top speed at mid straight now. It spends a long time with full aero downforce at about 70 mph. It was getting some wear on the trailing edge of the chassis, in spite of downstop limiters. Time to put a little more spring tension in the car. On the standard pan you would put in a little stiffer center spring. On my car, I went to 4 # fronts and 3# rears instead of 3 and 2. It handles the technical chicanes better more lightly sprung but now the track flows better. The harder springs worked well.

I had some oversteer (tail drifted out) on the last third of the sweeper. This was duplicated with the stiffer springs as there was a similar bias front to back. I wanted to raise the roll center in front. Some BMI 1/12 scales now have a similar setup to adjust as the dual A-arm front end I run. On a standard pan add a steeper reactive caster block like go from 0 degree to 5 degree. This will cut some caster late in the turn and reduce steering while rolled hard.

I had some choices
Raise Outer Upper A-arm up (already to max)
Lower Outer A-arm Down (already to min)
Raise lower A-arms inner pivot (problematic as it would raise the upper A-arms as well)
Lower the upper A-arm inner pivot (this was available with some trouble)

I sanded .020 inch of Aluminum off the 3 pedestals which support the front upper plate. A total of .050 inch removed, as I remove .030 when new. I did this with one Dremel. At home I use two. Cut the head off a long 4-40 bolt. I used this for an Arbor. I put the hourglass uprights on the arbor, placed the arbor in a couple of pinions with oil so it would rotate. Sanded the uprights with rotation measuring often. At home I use a second Dremmel to spin the arbor and sand with another Dremmel (or I use the lathe). I got additional suspension to body clearance as well.

Note on a standard sliding kingpin front end, removing some camber is the quickest way to raise the roll center a bit. Believe it or not.

The car was now very even in cornering. I had enough shock travel and room for the spring collar to obtain my 6 mm front ride height. I raised the rear up abourt 1.5 mm at the axle so my downstop limiters (red nuts hit side plate bottom) would be more effecttive. This was a good move at the high speed.

There were about 6 electrics and 1 Nitro 1/8 scale. The F1's were doing 28 second laps, the 13.5 1/12 scales, 24 second laps. My laps were in the mid 20's. With practice I should get this down a few more seconds and take on the 1/8 scale which was the only car close.

I hear there are 3 electric Serpents at the track now. Eventually I will cross paths with one.

I have the LRP 1 cell SXX in hand now. Next trip I will try it in the 1/12 Scimitar pan with maybe the 4.0 motor.

The new upper plate with 3 points of support instead of two and the through bolts is proving to be very rugged. Write me a mail if you need an upgrade.
John

John Stranahan

iTrader: (27)

Note there is a new 1/10 wide pan road test in the post above.

Scimitar 1/12 Scale
This was a strictly experimental car to see if you could fit dual A-arms with twin shocks in front and a 3-link with twin shocks in the back under a 1/12 body. The answer is yes. I am still a little less than an ounce overweight at 750 grams. 730 grams is the spec The intended use is a large outdoor track with mod motors so this will not present a problem. Installed presently is a 3.0. Also the LRP stock spec speed control which is supposed to handle 4.0 on two cells. I am running one cell. I will probably add a fan. The speed control has and outlet and a part number for a cooling fan. The car previously showed some promise with a stock motor. It had excellent turn in with little tendency to spin out. I was actually hitting the boards in front of the turn it turned so fast to start with. it turned kind of like a well set up mini Z car on a rubber track.
john

josedo

Hi John, you can check in youtube some of our pan car races going to: 1-5 adocarc mayo 2011. There you can see some shorts of races from February until May of this year, including races were carlos Di Vanna participates with your Scimitar 1/10 chassis. His pan car body is an orange Lola. I was lucky to win all five straight races. You can see how bumpy is our track; also you can see 1/5 scale cars doing some laps. José Álvarez.

John Stranahan

iTrader: (27)

Josedo-Thanks for the videos. I had no trouble finding them on you tube. Lots of fun. Note, I am still trying to build a few more Scimitar wide pans. Stay tuned.
john

John Stranahan

iTrader: (27)

Pod Stiffness
I notice CRC has come out with a new part to improve stiffness of the pod when running mod. It consists of a new wide top plate and an additional left side motor plate.

https://www.teamcrc.com/crc/modules....rticle&sid=136

The problem is pod flex.
I was getting some axle tramp with the standard Gen X 10 pod, converted to 3-link, when running mod. It was at high power levels. The car would loudly grip and then lose grip in a quick set of cycles. The pod was flexing and unflexing. I had reports as well. With the Scimitar wide pan, I solved the problem by going back to the Associated L3T type of pod harware. See the attached photo one (this is Scimitar #2 being built up). The change includes a full width Scimitar blade top plate and a very elegant and beautiful full length left side pod plate (this red set is made by CRC). I see a new left side pod plate in CRC's future. They used to have one with a simple Post near the front to catch that wide top plate. (Note the vertical shock tower post on the Scimitar will be red when the parts come in.)

Scimitar Front Chassis Strength


The Gen X 10 chassis is certainly well thought out for running stock and one cell. These are the predominant classes for the breed. When you put a mod on it an run it on a big outdoor track it lacks a little strength near the front. Here is what I did with the Scimitar wide pan to improve on it. See photo 2.

• The front end of the chassis is wider while the waist is a little narrower for good flex.
• There is more meat in front of the bumper mount screws.
• There is more meat to the sides of the chassis suspension mounting screws.
• Lightening holes are all smooth ellipses to remove stress risers that occur in sharp corners. (A stress riser concentrates force so that a crack or fracture will tend to occur there.)
• Notches with sharp corners are removed at the sides of the front. Again to remove stress risers.

Nothing really new or sensational, but small things that will stop the front of the chassis from getting compression fractures that have destroyed three of my previous frames. Not really broken all the way through, but broken enough that handling suffers.

Click the photos a second time for a larger view.
john

Chubba

Hi there, I got myself a new 1/10 pan car and having a few problems.

On throttle the rear is so twitchy and rear very loose and slides about suddenly. But on throttle during a long sweeper is fine and fast. What can I do to sort this out?

In terms of the ball Diff I am using ceramic 3.175mm balls and have changed to 48 pitch spur gears, at first when testing the ball diff seemed and sounded to be slipping. so I tigthened it up and sounded ok. On return the plastic which was holding the ceramic balls seemd to have melted/deformed against the diff plates.

I then stripped it all and rebuilt the diff and noticed that the ceramic balls only slightly touch the ball diff plates. is this right?

What am I doing wrong? and how can I sort this out?

Thanks

John Stranahan

iTrader: (27)

chubba-hopefully you installed a new gear after the meltdown. The balls need to only touch slightly but the gear should add no friction by touching both diff washers.

I check my tightness like this. grab the gear and left tire with the left hand. Now try and turn the right tire. It should be very hard to make it slip.

On CRC cars the inside hub and gear bearing are non flanged. A couple of flanged bearing may make contact difficult.

On the handling. First the diff has to be smooth and easy to rotate with no notchiness. Second on corner exit give a slight pause to the throttle while the front wheels straighten, then roll on the throttle gradually. Some rear looseness is a property of two wheel drive. Early and mid corner are adjusted with springs and caster. Use pink rear tires and purple front tires.
john

josedo

Hi John, I dont want to sound disrespectful but we call the Calandras 1/10 here like señoritas coming from Paris, too delicate.

ozzy-crawl

iTrader: (14)

had mine for 4 months,parts broken = 0
parts replaced =0
i run 1-2 times a week minimum