Coolest transmitter mod you will ever see:

Matt Shumaker made these awesome mods for his transmitter. He modified his transmitter to accept a 9db antenna to improve range. He also modded the steering wheel to increase the travel of the steering wheel without minimizing the steering endpoints on the car. This significantly reduces how twitchy an rc car can get at high speeds:

Here are pics of my modified DX3. It is running a 9DB gain antenna and (obviously) a new steering assembly. The reason for the antenna is range. I get 1500 feet uninterupted with the antenna. The big mod, though is the steering assembly. The story behind the assembly is an interesting one. Basically, I have my top speed car setup for normal daily driving, I.E. good handling and neutral steering. However, when setup that way, over 100 mph the steering is far too touchy. I have tried expo and I do not like dual rates. What I really wanted is farther steering wheel throw to give me finer control at speed, but still have full steering lock. This steering assembly a 3 to 1 reduction ratio. That gives me 3 times farther steering wheel travel, though still fully controllable. I love it! Oh, another reason I made the steering wheel assembly is simply because I can. It is nice to have my own CNC machine shop.

The assembly is comprised of carbon fiber, machined aluminum and a ball bearing supported titanium shaft. The steering wheel is a pink compound Jaco L4 rear wheel that is narrowed and trued down.

Anyway, I know this is not exactly a mod that everyone will want. But, I made it from scratch with materials I have on hand from my heli business. So, it cost me nothing and solves an odd top speed issue in an interesting way.

At this point, this transmitter is perfect for my particular needs.

Oh, it is more comfortable with the wheel in its current location. I love it!

Matt

Matt Shumaker's test body

Matt has been testing with a prototype custom lexan body. He wants to look at different designs that will give him more downforce. This is what he has to say:

Hey Guys,

I have found that I need more downforce than I had with my CF body. So, while I make changes to the CF body, I decided to make a simple, high downforce body for experimentation purposes, and this is what I came up with.

Now, bear in mind, the purpose of this project was to make the simplest body I could. So, I picked up some .060" lexan and went to the shop. 90 minutes later I had this body finished.

So, it is definately ugly with a sort of "Mad-Max" appeal. It reminds me of a late seventies 1/8 scale car.

Anyway, I have run the car at 75mph with this body (6S rather than the 12S it is setup for) for testing.

The car runs very well with this monstrosity, ugly though it is. It even corners very well with the downforce I am getting. The car has a bit of oversteer up to about 40mph. Beyond that, it weather vanes into the wind due to the large side dams acting as rudders. I let the car run for a good 3 to 4 seconds wound out at 75mph and it was well planted and relatively easy to control.

Anyway, I will be running the car tomorrow on 12S if the rain stays away. Tonight and tomorrow morning I am rebuilding the car. I stripped the pinion and spur doing some drag car launches as a test. After all, I have put 42 miles on the car since the CF body was made.

Matt

Matt Shumaker testing updates: capped tires are awesome!

Here are some modifications Matt is working on:

I have the body off the car and I am going to lengthen it by 1.5 inches, increase the chin spoiler leading edge length, and increase the height and length of the side air dams. The side air dams will be Lexan instead of CF because of their size (for esthetic reasons).

With the body off, I decided to do some gyro programming and overall drive train torture testing. In my testing (60 to 65 mph on the street in front of my house), I learned more about the car. #1 This is actually a great drifting car as long as I stay under 25% throttle. #2 The cap tires grip phenominally when they are very hot. #3 Cap tires have a higher chance of failure when hot.

I blew out my right rear cap doing some drag car launches. I was trying to get a better feel for the car under accelleration. My wife was watching when I told her "See that accelleration a crazy wheel spin?"-----"That was less than 50% throttle." Then I gave it about 75% throttle in a good solid launch. That heated up the tires (and layed some big black marks). On the next run, I gave it 50% for 1/2 second or so, then ramped it up to about 75% throttle and promptly blew the right rear cap. The tires were crazy hot and gummy. That is what blew it out.

At any rate, I have a spare pair of caps. Plus I am ordering 4 more.

I have been learning quite a bit about this car. Once I get the body modded, it will be ready for testing at a better strip.

Matt

Matt did some more testing today:

I went out and did some more testing. I decided to run the car on 4S and do some bashing around with it. What I found is interesting.

First of all, the car accellerates with very similar characteristics on 4S as 12S. That is, the traction never changed even though the voltage did. The car still accellerated at a peak of over 2Gs and an average of 1.5 to 1.8 Gs throughout the run. Also, the car handled the power in a very similar manor to running 12S. Therefore, I can safely assume that 12S is not too much for the chassis to handle. On 12S, the power system draws over 3800 watts on 12S and 1000 watts on 4S.

Now for some more numbers;

The car wound out at an indicated 57mph on 4S. That is probably closer to 60mph because I have a slight fudge factor of about 3% to 4% to allow for wheel spin. So, that 57mph is a very conservative number. I was quite surprised. I thought it wouldn't break 40mph with the motor KV and gearing I have on such a low S count. Very encouraging! Tomorrow I will do some more testing on 6S2P to see how the car does. What I am trying to do with this is get a better baseline on what the chassis is doing without having 4.5HP to deal with. In case you are wondering, driving a super powerful car is not a matter of simply having good throttle control with your trigger finger. It is extremely hard to hang onto that much power. AJlovering will have this same problem. Of course, too much power is a fun problem to have!

Well, I think that is about it for now.

Matt

Matt Shumaker: Too much power?

Matt Shumaker did some more testing with his car early this morning, this is what he has to say:

Oh, I just got in from some test running at 6AM before traffic built up on the road. I have come to a very interesting conclusion-------------- It is indeed possible to have too much horsepower. I am up to 4.54 HP (I keep squeazing a tiny bit more here and there) and the car just won't hook in the distance I have to work with. I ramp the car up to 85mph, then sqeeze the throttle and the tires smoke. They don't just spin, they SMOKE! I also ran off the road twice and rolled the car. One roll gave me over 18Gs of load! I torn off the chin spoiler on my body in one wreck. That is fine because I want to lengthen it for more nose downforce and I will make Lexan side dams that are larger than my CF dams for more rear downforce. These changes are needed for more traction and more straight line stability. I also need to get my high end gyro fixed. This gyro is not happy above 100 and my steering "Feel" goes completely away at that speed. My other gyro never felt vague as this one does at super high speed.

Anyway, this top speed thing is really alot harder than it looks. I know I have the horsepower and aerodynamics for EXTREMELY high speed, but I am overpowering my street and even my radio. My Eagle Tree is picking up alot of glitches even though they are not coming through my ESC and servo.

At any rate, the driveline held up, the power system held up, the chassis and all other components help up fine. I just need to get he power to the ground and regain my straight line tracking.

Oh, have been nervous to run the car on this street with so much power, weight and speed. That is a problem as well. I need a better place to run.

Matt

I wonder if there really is too much power. I don't really think so. Its just a matter of getting all that power to the ground. I am not going to let this distract me from my testing.

Matt Shumaker's Carbon Fiber Supercar

Matt says:

Well, I have been talking about this for a while and I felt it was time to show my car. For those who just want to know "How fast is it?" The simple answer is--------- I don't know. That is, I haven't had it wound out fully yet. I have seen 115mph on 6S while still accellerating big time. On 12S (different motor), the car went by at 100+ while wheel spinning an indicated 140 mph (4wd). Since then I have installed BSR cap tires. These tires hook very well. With the caps, the car has run 83mph at less than 30% throttle (in two seconds) and 100mph at 60% throttle. The weather stinks right now and the car has officially become faster than my street will allow. So, I am looking for a suitable runway to really wind it out.

Anyway, the car setup is as follows;

-Neu 1515/3D
-Thunder Power 2070 Extreme cells (12S)
-Castle Creations HV110 ESC
-Spectrum DX3 (love this radio)
-Futaba GY502 Gyro with digital steering servo
-TC4 drive components (basically stock other than a modified center driveshaft and 1 inch stretched wheelbase).
-BSR cap (radial) tires. AWESOME tires!
-Complete Eagle Tree data logging system with all accessories.
-Venom Speed Meter for wheel speed data (I have a radar gun too).
-CNC machined carbon fiber/plywood laminate chassis. This is an item I designed and made in my shop on my CNC with 7mm thick CF/ply laminate that is made to m y specs by my CF supplier for my helis products.
-CF body. I hand made the CF body by making a foam mold and laying the CF over the mold. The body by itself weighs 10.5 ounces. I need to thin it from the under side to shave a couple ounces.
-All up weight is 93 ounces.

The aerodynamics of this car are such that I have good downforce, but low drag. I did a HUGE amount of research and testing to come up with the final design. The front wheel wells are needed for front wheel steering clearance. I did quite a bit of testing to assure that the net drag of those wheel wells is zero. Also, the nose of the car went through numerous changes (hence the added body weight) to achieve the correct downforce/drag ralationship. I am not going to devulge the specifics of what I found as it is too lengthly to get into here.

The power system draws over 3800 watts continuous at full throttle. Also, the car accellerates at over 2.6 Gs (2.98 peak) and corners at roughly 2.5 Gs. (This is all data I have logged on my Eagle Tree).

Originally I speced the car for a Neu 1512. However, that motor built up with too much heat. So, I went to the 1515 you see with a finned can. That gave me a tad more power with a large improvement in heat dissipation. I also mounted two fans to the ESC and one to the motor.

When I got the car to the running point, I quickly found the motor heat issue and secondly, traction. Oh, also, the foam tires only last a few runs. So, I contacted John at BSR tires. He set me up with some touring car caps. These tires have good hook while allowing some wheel spin to protect the driveline from all the horsepower. They are also very long wearing. I am thrilled with the caps! Now, I just need to see if they will handle full speed.

I have about 30 to 40 hours in the body and about 30 to 40 more hours in the rest of the car (fabrication time only). Then I have about 5 hours in component programming and setup. Beyond that, I have about 100 hours in two previous TC4 setups to learn the drive system and what is needed for world class speed. So, this car has been hugely time consuming to develop.

At this point, the car has crazy horsepower (4.5hp), is super fast, handles (corners) very well, is reliable, runs relatively cool, and is very stable at high speed.

By far the most difficult part of the project was matching all components to work together, matching the drive system to the weight of the car and the CG, and getting the aerodynamincs matched to the chassis and capabilities of the car. When you are pushing the edge of the envelope, matching equipment and individual component setups is super critical!

Oh, I have so much power that gearing has proven to be only minimally important. I have gone up a few teeth and down a few teeth with very little affect. Basically I have it geared for 150 mph at full throttle under load. We shall see what it will actually do.

Anyway, I think that is it for now. I will give more information as questions are asked.

Matt

Matt Shumaker's car update

From Matt:

Today I finished the structural layers of CF on the body. The epoxy will dry over 2 to 3 days. By this weekend I should be removing the foam from the body. By the following weekend the inside of the body should be reinforced and the outside will be final sanded and clear epoxied ready for mounting.

The radio and all remaining electronics should be here this week. I will begin soldering all wires and mounting the large number of components while the body cures (over the next two weeks). I will also have to begin learning how to learn to use all the new goodies.

I have various little bits to make (center driveshaft, small mounts, etc). Those will be easy to make.

The wind tunnel is something I may or may not make. I hope to begin actual testing of the car this month. If the handling dictates, I will build the wind tunnel. This may be unavoidable. But, we shall see. The handling of the car is somewhat telling as far as wether or not wind tunnel tesing is necessary.

Basically, this rebuild consisted of the following;

New chassis made from proprietary 7mm thick CF/Plywood laminate.
Stretched wheelbase.
Stretched, hollow center driveshaft.
New motor (Neu 1512.2Y)
New packs Thunder Power Extreme 2070 cells in 12S configuration.
New ESC (Castle Creations HV110).
New radio (Nomadio Sensor 2.4 GHZ).
Hand laid carbon fiber aero body.
Complete data logging setup with telemetry.

This is about 80% brand new equipment and 20% hold over equipment from the previous car.

The car will weigh 90 to 95 ounces and have 4.3 HP. My personal goal is 150 MPH.

Matt

Video: Matt Schumaker's 90mph Associated FT TC4

Stock Associated FT TC4 with Hacker C40 12T on 6S Thunder Power lithium pack

According to Matt:

Believe it or not the chassis is almost totally stock, except for a few specific mods; The chassis. That is obvious. Another modded item is the center driveshaft. That shaft resonates HORRIBLY above a certain RPM. I modded my shaft by cutting the center of the shaft out (leaving only about 2 inches of each end) and made a sleeve out of K&S aluminum tube that was epoxied to the shaft ends. That gave me a hollow, large diameter, center driveshaft. That cured the resonation problem. Another important item is the rear toe-in. I used a suspension pivot mount from the front of the car on the rear (in front of the rear diff housing). This netted 1/4 degree rear toe-in rather than the 2.5 degree it came with. This gives far less rolling resistance and much better rear tire life. The motor mount is another obvious hand machined item.

Beyond that, the chassis is totally stock. I am even running the stock differentials with no problem. The car has seen 3HP at 80 ounces with no driveline problems. However, the latest incarnation (which hasn't run yet) is 90 ounces at 4.3 HP. I am not sure if the drivetrain will handle it. I hope so. Honestly, wheel spin is a decent clutching system to help the drive train survive.

Wait till you see the new setup! I am not giving away anything just yet, but it is very cool indeed!

Oh, it must be noted, I am not out to break the world record, per-se. I am trying to build the fastest, highest technology daily driveable street car possible. That means it will be very fast indeed. But, this car is not a dedicated top speed only car.

Think, Bugatti Veyron.

Mod Man's cars: This car has potential

I ran the car with the Vette C6 body today. It ran straight and pretty easy to drive. However, there is not enough downforce on the nose of the body. The car consistantly flips over backward at 85 MPH. So, I need to increase the downforce at the nose to compensate.

Anyway, it ran very smooth and stable. Oh, I also ran it without the steering gyro. It is harder to get up to speed because of the added steering input I had to give. But, that was OK for the most part. Basically, I nurse the car up to about 60 MPH, then nail it. At 60, the air holds the car straight.

Oh, the car hit 85 MPH with a bit more than 1/2 throttle. Also, the motor was not nearly at its limit. With the previous Hacker (small can motor) you could literally hear and feel the motor straining to push the car up to speed. With this big can Neu motor, the car just winds up to speed very willingly without so much as an odd sound or any appreciable heat build up. I am very pleased about that!

Also, I went up to a 56 tooth pinion. That gives me a final drive ratio of 3.17 to 1. That is good for a calculated 115MPH minimum under load. I will be going down a few teeth on the spur to get the ratio to 2.5 to 1. I also plan on going to higher capacity cells soon. The car pulls over 100 amps under load and is drawing my 6S pack down to 17 volts under load.

Here are a few picks of the car with the body. I am not planning on painting a body for it untill I get the aerodynamics worked out.

From Mod Man:
Here is my FT TC4. It is running 8S through a Neu 1512.2 motor. The car weighs 4.3 pounds and is pushing well over 3HP.

"They are all Associated cars, one FT TC4 (pretty much finished), RC12 L3 (all parts on hand, just need to build it) and an RC 10 L3 (most parts on hand). The TC4 has seen 92 MPH in its previous guise with a Stratus body and 113 without a body. But, it is totaly rebuilt now with about 1.5 times the power and far better aerodynamics.

The TC4 is built and just needs to be wired. It is running a Neu 1512.2 on 8S. The RC 12 L3 will be running a Neu 11 series on 6S. The RC 10 L3 is the bullet of the group. It will be running a Neu 1512 or 1515 on 12S.

The setup is as follows;

RC 10 L3
Castle Creations HV 110 ESC
Thunder Power Extreme 50C 2200 cells (12S)
Neu 1512 2.5

RC 12 L3
Neu 11 series motor (not telling about the wind)
Jazz 50 ESC
TP Extreme 2070 cells (6S)

Each car will run a flat chassis like my TC4.
All cars should be done by April.

Matt"