Turbocharged Cheetah --

[Sideslip]

The price difference I quoted was based on Rotax SA list prices.

If you import a motor yourself, that obviously changes a few things.

Please just check up on warrantee on imported unit. I don’t know how that is affected.

[AWACS]

Hi Turbo!
I asked the same question ca 6 months ago - no reply. So I am pretty sure you are the first to attempt this conversion. We will be watching your progress carefully if you continue
Hope it works - Good luck!

[bobthebuilder]

As a matter of interest ..... why are you replacing the existing engine?

[flybynite]

I think the turbo would be overkill. The 100 or even 95 hp motor is ample! Have you ever flown and felt that you needed that extra bit of turbo power in your Cheetah? I can honestly say that I have never felt the need for more than 100 hp in such a light aerie. And I have big friends and students!

I doubt if you will get any speed benefit. You should get better climb performance but a lekker prop like the Kiev 3 blade which is properly adjusted will surprise you. Big difference between this prop and a wooden 2 bladed prop on a Cheetah.

Fitting a 914 would be like installing a 300 hp motor in my Cessna 172

Now the brakes is another story. Please convince the boys at the factory to look at your option!!!

Regards

Larry

[Turbo]

Sideslip - i hear you, but i build my own race engines (albeit for cars and bikes as a hobby) quite successfully i might add, and love it, so regards Warranty, im not really bothered unless its a serious problem, but Rotax im sure will help - lets use the example where someone imports a kit plane, with engine -- if it fails 'under warranty' in whatever way, then Rotax will come to the party, its their engine regardless of which country it was shipped to.

No need to replace the 912 Extra in the cheetah at the moment, just that all my other toys are turbocharged, and im in the business, why not my plane , since it is a Rotax, designed for a turbo, why not install it. Its the same analogy once again, its there if i need it, and besides i enjoy my Ford F250 with its twin turbo V8 engine alot more than the old 4.9 normally aspirated straight 6 ... get my drift.

Lastly on a technical note -- the way i am able to setup the tuning (i will probably look at converting to fuel injection like the 914S supplied in the dallair F01 - which uses a Motec ECU which is automotive specific) and boost control on the engine, the plane will fly alot better in the sense that i wont have to use full throttle to achieve more than enough power to climb and outperform what i have currently, creating a longer lastling, less stressed engine.

I have looked at the gyro setups, and the way they are tuned, and how boost is controlled, its rudimentary, and can be improved on in many ways (compared to my other turbo setups) maybe its a bad idea, but its not for commercial use, its a 'home built plane' for my own use.

Regards the brakes -- the boys at the factory are well aware of this, and in fact use the same product on the Bush Cat -- Sideslip mentioned to me that in order to fit the brakes to the cheetah, the entire undercarriage would have to be replaced... too expensive just for brakes - so im going to go to some effort to fit these onto the stock under carriage -- it can definatly be done, i have started the project already, hopefully if time allows, i will continue over the weekend, problem is i want to fly at the same time which doesnt help -- maybe ill buy the two knuckles as they call them, and build them off the plane and bolt them on once completed.

[bobthebuilder]

...... Wow!

then Rotax will come to the party, its their engine regardless of which country it was shipped to

I would certainly check this with our local Rotax agent. They may deem it to be a grey import, and thus not support it all. The motorcycle boys are infamous for this practice. Admittedly, there are other sources for spares. Any modification to their product, no matter how well you know your game, will void the warranty. (If it is still under warranty?)

If you are not an approved Rotax maintenance mechanic, you probably shouldn't be doing any more than the most basic of maintenance. This is not only to protect the warranty, but it is also aviation law. Check out Part 44 CATS and CARS-NTCA Maintenance. Also, check with your AMO / AP. I stand to be corrected, but I suspect that the engine mods that you describe would need to be inspected, and signed out by the relevant parties. Mod reports will probably also be required by the CAA / Raasa. (Proving flights etc?) This is not only for the engine, but for the brakes too.

Please investigate all of this stuff. If there is an accident, your insurers will be well versed in how to nullify your policies. The CAA also imposes fines.

How well do you know the history of your newly purchased beast? How many hours has it run? Why was it removed from it's previous airframe? do you have supporting documentation for it? (Is this required?)

Please, don't let me dampen your spirits, i'm all for experimentation, but please do it with care.
Maybe join an EAA group too. (Experimental aircraft Association) There are loads of people who can help you there. PM me for details if you are keen.

[Boet]

Turbo, I would strongly advise you to go sit quietly in a remote corner, untill this urge has passed. The small gain is not worth the shlepp. Keep the original engine in your aeroplane, the performance is more than good. IF you really feel like doing something wortwhile with it, fit a VG set. See thread elsewhere on this forum. Now THAT is worth the trouble.

[bobthebuilder]

I am completely with you on this one Boet.

[Turbo]

botthebuilder and boet -- sound advise for sure, if i were younger (not that i am old) i would clasify the words as 'naysayers' but im alas, alot wiser through mistakes made of similar nature, and wont be going down that road again. I have already contacted CAA about the brakes, and the responce is quite simple "these are experimental aircraft, and classified as home built - do as you wish, as long as you are not altering any of the flying capabilities of the aircraft E.G wing design, exceeding the VNE etc" i was also told by three reputable people in the industry that an AP would obviously have to sign this off, and i will make sure this gets done according to law - for the record, the brakes should be finished tomorrow, i will post pictures of the build shortly, and report on the tests aswell.

Regards the engine -- i absolutely agree with you, and will follow the necessary procedures (where they exist -- remember the nice little "experimental aircraft" cloud cover that certain companies and orginizations use to disguise their dis-interest ... i love that phrase!) and ill make sure that all work caried out is inspected, tested, signed off -- but what i wont do is be turned away from the project, my mind is made up and i am going ahead with the mods (brakes first) and if it be so, ill have the first 914 turbo cheetah in S.A, who knows possibly the world.

If the Europeans can build a 914S 130HP and a 1500cc 915 Rotax and bang them into the FR01, i can install a stock Rotax 914 into a Cheetah -- who knows if the first one is done and is a success, i bet others will also want the upgrade - after all why not?

short and simple - sure there are procedures and laws, and i will follow them accordingly, in order to achieve the goals of making my plane into the tricked out piece of work i dreamed of having. Im sure most can relate to this...?

[bobthebuilder]

..... its your money!

[Boet]

Jaaaaa swaer. I rest my case. But please keep us all informed. We like to watch and learn..........

[Turbo]

Jaaaaa swaer. I rest my case. But please keep us all informed. We like to watch and learn..........

yeah will do -- engine arrives Thursday next week. Brakes with new rims will be installed monday if all goes well.

[Dobbs]

Not sure if I understood the references to the turbo earlier, but the turbo on the 914, certainly at most power settings is providing boost, and not only when the throttle is firewalled.

[Turbo]

Not sure if I understood the references to the turbo earlier, but the turbo on the 914, certainly at most power settings is providing boost, and not only when the throttle is firewalled.

boost is relative to engine load, if the throttle is closed, there will be no boost. Depending on turbo size, (this gets very technical, and will take up 4 pages if i go into it in detail) sometimes boost is generated at cruise... now this is why there is an electronically controlled wastegate actuator. you are able to open or close this wastegate independantly to the throttle specifically for protecting the engine/turbo from excessive heat and engine failure - hense used for climbing and take off only.

[Thatchman]

WTF 4