MY cheetah - ZU-DHH rebuild project

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John Boucher
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Re: MY cheetah - ZU-DHH rebuild project

Postby John Boucher » Tue Nov 09, 2010 11:59 am

True iro of the Warp hubs.... quite a few have had catastrophic failures in this regard!
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Re: MY cheetah - ZU-DHH rebuild project

Postby Stephan van Tonder » Tue Nov 09, 2010 3:28 pm

We have seen at least 3 warp drive hub failures and all were correctly torqued. It's a 'common' problem and something that is going to cause a problem one of these days. We have shown the CAA inspectors a couple of the hubs as well.
I know what you say about the 618 and everybody but me is keen to see me use it. I just have a personal issue about 2 strokes. I just don't trust the buggers and I'd much rather fly behind a 912 if I can.
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Re: MY cheetah - ZU-DHH rebuild project

Postby RV4ker (RIP) » Tue Nov 09, 2010 3:32 pm

Stephan van Tonder wrote:We have seen at least 3 warp drive hub failures and all were correctly torqued. It's a 'common' problem and something that is going to cause a problem one of these days. We have shown the CAA inspectors a couple of the hubs as well.
I know what you say about the 618 and everybody but me is keen to see me use it. I just have a personal issue about 2 strokes. I just don't trust the buggers and I'd much rather fly behind a 912 if I can.
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Re: MY cheetah - ZU-DHH rebuild project

Postby John Boucher » Tue Nov 09, 2010 3:46 pm

Well I'm putting on my P-PROP again.... STRONG - RELIABLE - LOOKS GOOD - IT WORKS!

Just got off the phone with Mike... I am not going to replace the Warp's hub. It's going to find a nice spot in my bar! (^^)
Last edited by John Boucher on Tue Nov 09, 2010 6:41 pm, edited 1 time in total.
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Re: MY cheetah - ZU-DHH rebuild project

Postby Mogas » Tue Nov 09, 2010 6:29 pm

Best of luck with your rebuild Stephan!
Have you considered a Jabiru 80/85?
We are very happy with ours, the secret seems to be correct propping and a nice sleek nose (which the Cheetah already has)
Have seen a couple of the older 80s go for about 40-50k lately and they are very inexpensive to overhaul.
Oh yes, Pprop is the way to go! have also seen lots of cracked Warpdrive hubs.
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Re: MY cheetah - ZU-DHH rebuild project

Postby SkySketch » Tue Nov 09, 2010 7:49 pm

Mogas has a good suggestion there with the Jab motor. Well priced and a very good motor!

Good luck with the rebuild. Kind Regards
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Re: MY cheetah - ZU-DHH rebuild project

Postby Stephan van Tonder » Tue Nov 09, 2010 8:04 pm

When I first looked at Cheetahs I flew one with the 80 hp jab motor. Because of the small prop(no reducion drive) they feel very lazy out of the blocks and seem to eat a lot of runway before getting airborne. Once going it feels OK and it cruises at the same speed as the 80 hp rotax. But side by side the 912 simply out climbs and out accelerates it even the 80 hp 912. The direct drive motors seem to do better in sleek airplanes that are relatively fast. On the draggy stuff like cheethas they don't seem so great. But hey if I can fall over one I won't say no either. Thing is right now there is a 912S sitting avialable if only i can sell The 618 or the other airplane.
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Re: MY cheetah - ZU-DHH rebuild project

Postby Rhodie » Thu Nov 11, 2010 2:07 pm

"this is where the thanks come in. THANKS VERY much - there was no other way that I would ever have been able to buy one. I am forever indebted."

Stephan, You are right, Larry is one of the real good guys. Earlier this year on returning from Ballito, and having stopped over at Ladysmith for a most welcome breakfast, my Cheetah experienced a very serious electrical short on start up. Larry allowed me the use of his hanger and when I returned with the Rainbow guys to do the necessary repairs, once again Larry went out of his way to assist with anything we required.

All the very best with your rebuild and hopefully will see you in the air soon


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Re: MY cheetah - ZU-DHH rebuild project

Postby Stephan van Tonder » Mon Nov 15, 2010 10:58 am

Right 912 is secured for the project. Engine has 328 hours on. Didn't get to do much this weekend but hung the cheetah on a gantry so I can start sripping the body work. The top right fugelage tube is bent and tehre is 2 small holes in the fabric at the bottom so I have to basically disassemble the fuse anyway.
We took the bits off the 912 that is ex thunderbird(where it comes from) and just checked that everything else seems in order. Compression is healthy and the plugs look good so I think the engine should be fine.
Wing asre fully disassembled and awaiting the audit report from Jenja and the parts list to order.
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Re: MY cheetah - ZU-DHH rebuild project

Postby Stephan van Tonder » Sat Nov 27, 2010 10:25 pm

Right started stripping this morning and basically took the front bodywork apart. Still at this point I have found the one bent wing bracket and the Right top fuselage longeron pipe that is bent, Apart from the damage to the cowling and spats fibreglass the cabin fiaring has absolutely no damage. Rest of the fuse also undamaged. We are taking the whole thing apart though just to be sure. Will also give us the chance to refresh any worn parts and clean everything up. Pics from start this morning to where I stoppped.
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Re: MY cheetah - ZU-DHH rebuild project

Postby flybynite » Sun Nov 28, 2010 9:54 am

Haai Stephan

Lyk goed - Onthou my free flip as sy weer mooi lyk! :)

Groete


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Re: MY cheetah - ZU-DHH rebuild project

Postby Stephan van Tonder » Sun Nov 28, 2010 7:10 pm

As for normal wear type items on a high hour cheetah- well the only thing we have found worn is the lower stop bolt on the nose gear. Except for the fact it was bent in the accident it has some serious wear.
These are the items I have found so far. first the stop bolt - look at the wear around the shaft. This is the main bolt that takes the rebound when the landing gear extends.
Next it the top righ rear fuse tube that got bent as the wing got pushed backwards and the last is the cross brace tube form the top right cab mount that got pulled out as that tube bent.
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Re: MY cheetah - ZU-DHH rebuild project

Postby ZAZU » Wed Dec 01, 2010 10:59 am

Hi Stephan & co

To get back to the Warp drive hub failures, do you have more info please.

Were the failures on a specific engine type, two stroke/4 stroke engines, reduction drives with/without slipper clutch(Rotax), and how many hours were done on these props?

Also, were the failures on the "heavy duty" hubs?
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Re: MY cheetah - ZU-DHH rebuild project

Postby Stephan van Tonder » Mon Dec 06, 2010 10:07 am

Right so saturday morning saw me stripping the rest of the fuselage to get the bent tube out and by saturday around 10:00 this is where we were.
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Re: MY cheetah - ZU-DHH rebuild project

Postby German » Mon Dec 06, 2010 5:48 pm

This is what I like about the Cheetah.You can repair/remove as you like because it is bolted together.
I think it is also stronger because it can "move/twist" as if it were welded it would crack.

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