8 inch disc brake kit for Cheetah - COMPLETED

[John Boucher]

Cheetah -fantastic little aircraft & excellent value for money.

Yes they are.... as I have said... to complete the package the only thing I have ever complained about is the brakes. Never about Rainbow / Skyreach / all the great friendly people there or their service and support.... have only moaned about the brakes!

[Turbo]

I love my Cheetah, and im glad i made this choice for my first ever plane -- i doubt i will ever sell him!!

anyways here is another update for those interested. The shafts were welded today, by a coded welder, i then media blasted them, and sent them in for nickel plating (i chose silver after all, i was going to go orange ...) this will be complete tomorrow, and installation will happen tomorrow depending on flying arrangements with Paul.

in the mean time, an update on the assembly of the gear. Firstly, the brakes were setup without spacers between the two bearings in the hub. The setup is required to be assembled and hand tightened with the lock nut supplied and the caliper held in place with a grub screw (yup you guessed it, i modified this design - it must be the perfectionist in me and the good advise from old Eddy and Aidan and Oom Paul! -- thanks gents, project is coming together nicely!!) We made up two spacers, installed them between the two bearings, and reinstalled the bearings into the hub <pics below>

The new shafts were machined to fit onto the short stubs cut off the spare knuckles i purchased, and then welded into place -- here are the pictures of how this all goes toether with the rim. enjoy.

[Turbo]

hey guys,

Today was D-day -- Aidan and I collected the nickel plated knuckles after they were welded by a coded welder - We installed the brake upgrade and tested it with the help of Aidan and Paul (thanks for the tool to bleed the brakes, saved us alot of time Paul!!) -- Firstly let me take you through the upgrade step by step -- ill skip the 6 trips i had to do, to go buy frikking tools and bits and bobs -- Total time required to remove the old brakes, lines, wheels, knuckles, bolts, and replace with new, aswell as the newly manufactured knuckles with wheels and brakes installed on the wheeels, was 3 and a half hours! Not long at all.

OK first thing i noticed after the install, was that the wheels sit PERFECTLY on the ground - the previous original Rainbow wheels had a ridiculous amount of camber, and toe in --- dont ask about my tires, as they looked horrible and lasted 30 hours .... now the new knuckles and wheels - the tires sit in line with the plane and no camber at all. Secondly we made the shafts so that there is some working space between the knuckles and the brake components (disc, caliper etc) and the double whammy was pointed out to us by Paul, IF in the event you have a flat tire, (like Paul did and almost wrote the plane off!!) the tire sits far enough away from the knuckle and brake parts, that it wont make contact and suddenly stop the wheel from turning ( 360's here we come!) with the drum brakes, the tire is able to make contact with the drum and other hardware, stopping the wheel from turning, and well you can guess the rest.

No more drag or binding on the wheel whilst taxiing and take off (this alone should be reason for anyone with a Cheetah to upgrade to discs) -- at the same time its so easy to pull and push around into and out of the hangar ... Remember, the brake kit includes FLOATING discs, not fixed.

The grip inside the plane is so comfy and soft, and operation is 'one finger capable' well thats all it takes to stop -- one finger, and you dont need much pressure either. Once everything was installed, and we stopped oogling over how nice the job came out -- Paul and I decided to go for a taxi, well a 3km taxi -- to 03, down 03, and backtrack 03 again to my hangar- during this time i was riding the brakes all the way --

The first application of the brake lever was ----- well PAP, the brake discs and pads were brand new, and the discs had a coating on it to prevent corrosion, which whilst we taxiid up and down, heated and eventually wore off, and the pads heated up and the disc started to bed in slightly. The feel got sharper and the brakes started to bite.... well needless to say, the single finger action is so smooth, and the plane brakes 100% straight, even at 40mph (dont worry we had down elevator) and with a convincing brake application the plane tracked straight up 03.

Guys once the wheels were installed with the hardware attached, it took literally 45 minutes to run the lines, cable tie them to the spar running forward to the undercarriage, connect the brass fittings, secure them to the planes structure under the covers inside, and bleed the system. The brake lines are transparent, so you can see the red ATF fluid inside it, and obviously the air bubbles aswell -- making bleeding so easy! once bled, the first application of the brake was effortless and met with a nice strong feel to the lever.

Pros:-Easy single finger operation
No more binding brakes (John Boucher -- thats for you!)
New polished wheels with brakes on look great
The product operates seamlessly
The product performance exceeded my expectations
Quick easy installation
High quality product
Many improved features over the stock drum brakes (punctured tire making contact with the drum and locking the wheel)
Price of the product worth every cent!
Not to mention how good it looks!!

Cons:-
IF you choose 8 inch wheels like i did, there is a little bit of fabrication to be done to make this work (but i have done it and it is now simple to do again)
Rainbow dont supply these stock standard with the plane --

Here are some pics -- they are poor quality, i will take some more with a proper camera and repost for all to see on Sunday when i fly her for the first time. Its a real pity that the brakes are not offered as an option for the Cheetah owners (not bush cat) anyways, the conversion is checked, approved, and signed off by an AP -- and i am ready for take off! Simple as that!

Next project -- the first turbocharged Cheetah in South Africa -- possibly the world ....

[John Boucher]

Well done on the installation Turbo!! Really looks top notch. So do you start a "production" line of the standard sized rims? I say standard sized wheels because of the spats.

[Turbo]

John

What diameter rims are you using? The Stock 8 inch? or smaller? The width of the rim is optional, so you can use spats with them, my spats are for the stock rims and tires, and actually fit over my new rims and tires - but for comfort, i wouldnt use anything wider than the 8 inch rim with 4 inch wide tires. My original rims are 8 inch, with 6 inch wide tires - up to you. One thing i never investigated entirely was how to mount the spats onto my new rims, as the wheel nut sits inside the rim and does not protrude out the side of it like the stock unit -- i didnt want to use the Spats as the rims look that good that covering them up just makes pumping tires and seeing the setup for inspections that much more diffidult (near impossible) also the tires have had absolutely no effect on the flying speed (drag) even with the larger tires on my Cheetah -- perhaps at much higher speeds they could, but i seriously doubt you will notice it at all. (Spats -- work in progress, ill check on how this can be done and let you know -- probably a spacer like the stock unit will be required to fit them)

To make up the shafts is a piece of pie -- i have made drawings of the shafts and can reproduce them if you need. If i were to help out, I would use my old knuckles form my Cheetah as service exchange units, and then require your old knuckles as a core to make the next units from and so on. I could also supply you with the premade shafts if you want to do the job yourself, all you would have to do is weld them onto the knuckles and carry out the installation of the kit.

There are two options in Axle diameter 5/8inch and 3/4inch -- I have made the adapted 3/4 inch axles to fit the kit as they are stronger -- not that the cheetah needs it at all!! I dont think there has been an incident reported where the shafts have ever been bent or broken - but as you will learn, i like to over-engineer everything (914 into a cheettah ) once again up to you - note that there is no cost savings at all between the 5/8inch or 3/4 inch units.

As far as costs go -- its the rims that cost more, but are REAL TRICK pieces, and TUBELESS!!! If you get a puncture, you repair it with a normal car puncture repair kit, which you can keep in th eplane with you at all times. The best part about it is the fact that you do not have to strip the tire and tube off the rim to repair it. Its quick and easy and costs no time or effort to repair - IF you need to.

Let me know what you want to do, and ill help you where i can.

PS:- I tested the new rig today with a flight from FASI to Klipriver (1 touch and go) and then to Circus for a landing to inspect the rims, brakes etc, and then back to FASI again -- i filmed the entire trip on my ISAW (better than Gopro) obviously showing the landing gear and wheels etc, and man o man am i impressed with myself, If i may say so myself. The kits works seamlessly, and the brakes have started to bed in nicely, and BITE more and more with every mm of finger travel you give it - and you honestly dont need to give it much at all! simply put -- I LOVE THESE WHEELS AND BRAKES!

[AWACS]

Turbo,
Finally, progress......on this very ooooold complaint on the Cheetah. It looks the part as well.

Congratulations!!
I have been following your progress with great excitement - (Hope Mike & crew also reads this post and memorise).

We are definitely interested to be the second Cheetah around with these brakes - I had a close call over the weekend on Tribal Crocs runway on the landing due the BAD brakes on the Cheetah.
In short, could not agree more that this is probably the only shortcoming on an otherwise superb aircraft!

Will contact you later

[Turbo]

Turbo,
Finally, progress......on this very ooooold complaint on the Cheetah. It looks the part as well.

Congratulations!!
I have been following your progress with great excitement - (Hope Mike & crew also reads this post and memorise).

We are definitely interested to be the second Cheetah around with these brakes - I had a close call over the weekend on Tribal Crocs runway on the landing due the BAD brakes on the Cheetah.
In short, could not agree more that this is probably the only shortcoming on an otherwise superb aircraft!

Will contact you later

Thanks AWACS -- nice to chat to you. As promised, i have emailed Black Max with pictures of the upgrade, and asked for preferrential pricing so we can carry this across to the Cheetah owners. Lets see if we can get a complete brake conversion installed into a plane for less than R5K -- if so, i believe we have a winner considering that Rainbow quoted R20K+ but mentioned that they would need to change the undercarriage to fit the disc brakes that the Bush cat had on....

There are a few mods i did to the existing Black Max brake setup to make it easier to install and make it more reliable (FOR OUR APPLICATION - the stock brakes they make are reliable, dont read this wrong!) and i prefer to make up the enlarged axles to beaf up the kncukles. Lastly my choice for the 3/4" axle choice was so that i would NEVER have to replace wheel bearings, or axles no matter how hard i land or how much taxiing i do -- its somply put BULLET PROOF!

Next project after the 914 conversion, is the nose wheel .... im not fond of the design much.

[Turbo]

hi all,

just an update for those interested -- i have got a price for a kit consisting of all the components to fit to the Cheetah in order to maintain the rear spats. This is a custom set of parts to compliment the manufactured axles that i make up. It is the exact same kit i have on my Cheetah, just EXCLUDING the wheels.

So the project contents are as follows:-

1) Custom machined 3/4" axles with adaption for fitment of the rear Spats to fit the stock Cheetah 8inch rims and 4 inch wide tires (this i will machine and weld onto a donor set of knuckles for you- as i did my own, all welding is done by a coded welder, and correct materials used)
2) CNC brake lever
3) 2 x CNC axle hub with 3/4" bearings and spacer between hub and caliper
4) 2 x CNC Calipers with brake pads
5) 2 x Steel brake discs
6) Full set of hydraulic fittings, and bleed screws with lines
7) Panel mount hand brake valve
All ancilliaries like nylock nut, washer etc

Total cost will be around the R5800.00 mark - without installation. This is a bolt-on kit, and anyone that knows what both ends of a spanner looks like will be able to install this himself. Bleeding is tricky, but i have a method which will help you out aswell and takes a max of 2 minutes.

Keep in mind that the majority of the kit is imported, and fluctuation in Exchange rate will affect the costing - i dont make any money on this, so there is no room for me to absorb any costs if the exchnage rate goes for any more of a ball of s%%*t

Any interested parties, let me know, and i will continue as a first come first served basis - one project at a time.

[John Boucher]

Hi Turbo

Would you want the knuckles sent to you for modification prior or would you then use that set as a "swop-out" set?

I am really interested even though it may be short lived because of my ex-wife relentlessly pushing for the sale of my aircraft!

[Turbo]

Hi Turbo

Would you want the knuckles sent to you for modification prior or would you then use that set as a "swop-out" set?

I am really interested even though it may be short lived because of my ex-wife relentlessly pushing for the sale of my aircraft!

Hi John,

No i have my knuckles that came off my Cheetah which i will use, in return i will need yours sent to me once your new ones are installed, so i have a set for the next plane.

Re your wife -- sorry to hear man, what to do ....

[John Boucher]

Re your wife --

EX EX EX wife....

Okay, that makes it easier but would prefer sending mine as they are relatively new as they were replaced at the 1000hr service

[Air Hog]

EX EX EX wife....

Jis John, how many times did you marry her?

[John Boucher]

Hey Johan.... what can I say?

[Turbo]

[quote="
Okay, that makes it easier but would prefer sending mine as they are relatively new as they were replaced at the 1000hr service [/quote]

No problem boet -- i will make as fast as i can with them, so you are not grounded for too long.

[John Boucher]

Yippeeeeeeeeee..... decision made and CXO will get the Turbo Black Max treatment

All that must happen thereafter is I must try and "retain" her to enjoy!