New tandem gyro

Chuck, The 618 in the two seater is worked pretty hard with training etc.All I ever did was the normal recommended servicing.Just keep the engine clean and everything that goes into it clean(Air,fuel).I also took the Rave valves out every 50 hrs and cleaned. Ive allways used a good quality spin on cartridge type fuel filter.
Mike, have been on DW's for about 10 years and owned about 5 sets and theres not much around that would beat them for efficiency.The trouble is that a $1500 set of blades can end up costing over 3 grand to get them over here with the exchange rate,freight,taxes etc etc. I was (am?)the agent here in OZ but anyone wanting a set i just give them the details and they orginize it themselves.I think theres a few sets coming over every now and then.
regards,
 

Chuck Irby

Platinum Member
Murray, thank you for that info. Three more questions, please:

1. Did the Rave's have much carbon build-up?

2. What oil do you use in the Rotax, and at what ratio? (I've been using Amsoil 100:1 at a ratio of 80:1)

3. Did you ever have a problem with the rotary valve oiler reservoir loosing oil from the vent hole in the top of the cap?
 

Doug Riley

Platinum Member
I had a 618 on my Dominator tandem for a few dozen hours. It had been on a single-seat Dom. before I bought it. I replaced it with a 912S (a.k.a. 912$)because it didn't have enough power to fly the big guys on little country strips in the summer.

I had very little trouble with the 618. The rotary valve and RAVEs gave no difficulty. I understand that the RAVEs are more troublesome in a lighter machine, where one throttles back to 5000 or so at cruise. With two aboard, I was running 6000 continuously. That seems to keep the RAVEs clean. I used AV-2 oil (no longer available, but I bought a lifetime supply!)

I disconnected the oil injector (made me nervous with its little nylon drive gear) and ran 50:1 premix.

The muffler has an odd construction, in that it's two layers of thin metal rather than one thick one as in other Rotax models. You can't weld brackets to it and expect it to hold up. I had to replace mine, at a cost of over $750 and 3-4 months' wait. I went to a no-weld strap system for my second muffler mount.

The case seals (especially the PTO end) can develop air leaks at very low hours. This shows up as a gradual rise in EGT on only the rear cylinder. The quick 'n dirty fix is to richen the main jet on this cyl only, by .10 or more. Eventually, you have to replace the seals.
 

Chuck Irby

Platinum Member
Hello Doug Riley, and thanks for sharing your 618 experience with us. I removed my engine oiler as well and have been using 8 ounces of AmsOil 100:1 two stroke oil at a rate of 8 ounces per 5 gallons of fuel.

Doug, did you ever have a problem with oil escaping through the vent hole in the cap of the rotary valve oil reservoir? That seems to be where mine is loosing oil. I'm beginning to wonder if it had something (maybe a membrane that would still allow it to breath) under the cap that I have lost.
 

Chuck Irby

Platinum Member
Doug, do you happen to remember if it had anything on top other than the bare plastic cap with about a .100" hole in it? Thank you again, Doug.
 

Doug Riley

Platinum Member
Chuck, I don't remember. I wonder if you're getting some blow-back up the oiler tube because crankcase pressure is leaking into some space where it doesn't belong? I don't believe that there's supposed to be any pressure backing up into that little oil tank. Maybe others who run 582's or 532's will know...
 
Chuck, Ive only run the 618 with the oil injetion with it at recomended settings.The ratio varies with engine rpm as far as im aware.Probably 50/1 full throttle and down to about 80/1 at idle,dont recall where I read that. Ive allways used Castrol super TT with good results,not sure wether you get it over there. The rave valves were never to bad when i took them out but if you leave them too long they can be difficult to remove.I let them soak for a while then a rub with very light sandpaper along with the hole they go into.Be extra carefull when re-assembling if they are upside down they'll hit the piston. My 618 was proped to 6450 in a climb and it seemed to be happy at that.I allways used 96 octane or above including avgas.
 

bones

Gold Member
Chuck,
I'm at the moment running a 532 and have just done an engine o/h and though i havent done a lot of hrs since, i think that i've got the same problem although still trying to get to the bottom of some other leaks ect, but mine just has a rubber seal under the lid with a ver small hole into to allow the pressure equallise
 

Chuck Irby

Platinum Member
Murray, thanks a lot for all your help. I really appreciate it.

Mark, That's the information I needed about the cap. Thanks a lot!

A big WELCOME to the forum, to you both.
 

ventana7

Gold Member
Murray,

Good to see you up on the US forum.

I took some of my early training with Murray in that machine and it was VERY stable flys pretty much like a 2 place dominator. I loved everything about it except the pink color.

Rob
 
Hello Rob, It must be the colour that makes it so stable,there's a RAF in the same hanger and it dos'nt fly anywhere near as well,It's black. When are you coming back to OZ?.
 

Aussie_Paul

A reforming stirrer!!!!!
Hey Murray, tell Allan that I have all the info needed to make that black love of his life a heck of a lot better. I hate seeing things not working as it could.

Aussie Paul.:)
 
Paul, All the details on making that machine better have allready been relayed to Alan years ago by me. He's just got to stop flying long enough to do the work.,maybe when his Butterfly is up and running he'll let me at it!!.
 

Aussie_Paul

A reforming stirrer!!!!!
That's great Murray..

That's great Murray..

.. what are your suggestions for Allans Raf?

Aussie Paul. :)
 
Where do you start??!!, The rudder and HS are OK unless he decides to go to a gear reduction,not sure if you can turn the RAF redrive down the other way,would help matters if you could.From the COG data on the RAF's and from looking at the Sparrow Hawk photo's a rough estimate would be to raise the cabin around 18 inches,maybe more if the redrive stays up.Are there any Sparrow Hawk drivers out there that can tell me how high the cabin was raised?. The landing gear would need major mod's but its all fairly strait forward.Are there any safety mods that any of you RAF owners have done?.
 

mrford61

Senior Member
murraybarker said:
The rudder and HS are OK unless he decides to go to a gear reduction
G,day Murray,

Just wondering how the gear reduction affects the tail ?

Take into account I am not very techo minded.

Another excellent machine by the way.

Mark Clifford.
 
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