New tandem gyro

[murraybarker]

New tandem gyro,comments please.

[Chuck Irby]

It looks real good Murray. Interesting design that I'd like to see closer. Did you stick build it or was it a kit, and whose design?

[murraybarker]

Hello Chuck, It is my own design but basicly I have been building them along the Dominator style for about twelve years now.The gyro in the photo is completly "stick" built.

[murraybarker]

Heres another.

[Rando]

Very nice! Wish I had one just like it so I could take my friends for a ride. Someday I hope to own a 2-place.

[Chuck Irby]

Very nice, Murray. How many have you built? Is that a 912 on the first one?

Not being familiar with Australia, are you very from the other Aussies who are members of this forum?

[GyroRon]

Nice machines! My only comment is I don't like how the blade strap is up against the windshield. The dominators have the pivot tube extending out from the front of the pod a foot or so, and the tube is built strong enough to use for moving the gyro around and to tie the blade strap to.

Chuck the first gyro is powered by a Subaru EJ-22 and the Second one appears to be powered with the 618 Rotax.

[Chuck Irby]

I agree with you Ron, about the blade strap and the Pitot Tube (not pivot tube).

[GyroRon]

Whoopsie!!!

[bogman]

Ya,ll are going to give Chuck E a heart flutter callin that Petcock tube a Pedot tube:D

[Doug Riley]

How does the vertical CG location come out? A bit below the thrust line? Above? Right on?

It looks close but looks are sometimes deceiving.

[jucie]

Nice looking machine, Murray. I bet it flies very well. Congratulations.

[Dean_Dolph]

How does the vertical CG location come out? A bit below the thrust line? Above? Right on?
It looks close but looks are sometimes deceiving.
Doug, this is true, as you have pointed out with the GyroBee. And the one thing I was hoping for from you people on the ASTM Stability Standards sub-committee was a requirement that the vertical Cg be placarded and/or visibly and permanently identified on the LSA machines. Was this ever considered or would that have been 'perscriptive'?

[Doug Riley]

Dean, it would be "prescriptive" if the standard said the CG had to be within X inches of thrustline, or some such thing. The FAA wouldn't accept design prescriptions, only performance standards. This frustrated some committee members, but probably is the politically wise way of getting to the same result.

However, I believe the CG location in the X and Y axes (maybe Z, too; can't recall) must be called out in the aircraft manual. Greg Gremminger could confirm this.

[murraybarker]

Hello All, Answers to questions. Yes the second one is powererd by a 618 and I flew about 500 hours on it before selling. The first one is an ej22 with a Hirth gear box.It only has 8 hours so far.The blade strap is only tied to the front stick untill a tie down is put on the front.
I think the closest to other forum users is 1000 kms(600miles),that would be Tim McClure.Dont know where the V cog is yet.The pink machine is close to a dominator thrust line and is very stable.The white machines TL is about 4 inches higher and so far I dont think its as good as the old one.

[Chuck Irby]

Thanks for sharing them with us, Murray. Did you ever have to do any repair work to the 618 with 500 hours? (I have a 618 on my Dominator single)

[MikeBoyette]

Murray,
Very nice machines. What blades are you using?

[murraybarker]

Chuck,My mistake ,only around 400 hrs on the pink gyro.I did about 260 hrs on the first engine and came across a brand new one for a good price so in it went! The old engine went into a single seater.Never really had a problem with either engine.
Mike, the blades on the white gyro are composite construction and are made a couple hrs drive from where i live.They are tapered and twisted with a diferent airfoil at the root and tips. The blades on the pink gyro are made by some dude down in Florida,Ernie I think his name is ???

[MikeBoyette]

Murray,
I think I know that guy, from where I can't recall. I thought those were DW's on the pink machine. Any reason for not going back to DW's other than the location of the manufacturer?

[Chuck Irby]

Thank you Murray. I have right at 100 hours on my 618. Any advice for making it last would be appreciated.

That's pretty neat . . . some dude down in Florida, Ernie I think his name is ???

[murraybarker]

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]

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]

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]

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.

[Doug Riley]

Chuck, nope, I never had any problem with the valve oiler. Its oil consumption was almost nil.

[Chuck Irby]

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]

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...

[GyroRon]

chuck there IS something in the top of the cap, just not sure how to describe it.

[Chuck Irby]

Doug and Ron, Thanx guys. I'll pursue a resolution on my end.

[murraybarker]

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]

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]

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]

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

[murraybarker]

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]

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.:)

[murraybarker]

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]

.. what are your suggestions for Allans Raf?

Aussie Paul. :)

[murraybarker]

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?.

[birdy]

Changed over to a 914. ;) :D

[mrford61]

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.

[murraybarker]

Hello Mark, The RAF tail is offset one way to counteract the torque,If you put a gear reduction instead of the belt the prop will spin the opposite way.If he went to a conventional tail (Tall Tail) he wouldnt have a problem.
Birdy, with the trouble he's had lately with his engine you could nearly be right,but being a lowly Qantas driver he wouldnt have that sort of money to splash around like you :D

[Aussie_Paul]

Not knowing exactly what Allan has already done, this is what we do to a standard Raf, probably worth less than 2 cents...

Have the Raf sitting on the front 3 wheels with ballast in the cabin, and place a support under the tail wheel. Cut the keel approx 4" behind the lower mast.

Slide the engine and redrive down the mast 6".

The "L" brackets that attach the rods that go from the redrive to the seat belt attachment bracket have to be turned upside down and mounted under the seat belt attachment bracket.

If living in a cold area, using doors, and having a stab without fins, undo the rudder cables and slide the rear keel back 6 to 8 ".

Make crush plates to attach the now lowered and maybe moved backwards rear keel to the front 4" that was left behind the mast, allowing for prop to keel clearance. This will have the rear keel with an upward rearward slope to give any fixed stabs approx 3 degrees negative AoA.

Next is a definate must as well. Move the axle back 4" by shortening the rear trailing arms, and placing a plug into the top of the axle to mast strut with a 3/8" unf tapped thread. Wind all the way in a 3/8" rod end with a lock nut. The rod end is attached to the lowerest section of the brackets that were slid down the mast 6". There is usually a dimple to center the 3/8" drill.The new rod end can be used to bow the axle a little as per the Raf construction manual.

If the rear keel was moved rearward, the rudder cables need an alloy rod/welded chain or cable extention.

Boy!!!!! what a difference this makes, particularlly moving the axle. With the machine now closer to CLT there is not as much nose down push of the high thrust line and the nose comes up too early and you have to push the stick so far forward to place the nosewheel back onto the ground the the rotor disc angle is so low that it takes forever to get the rotors up. You get airspeed quickly but not RRPM. It is my opnion that every Raf with the weight of a stab out the rear should move the axle back a few inches.


If I had enough interest I would package together the required bits and instructions with picsf or sale. Anyone seriously interested?

Allans machine looks like a dog when he takes off. :eek: Allan has to drag the tail wheel on the ground for sooo long to get his rotors up.

Allan needs a little more rotor diameter. I would suggest Robs 30' blades with the taper etc and reducing the torque tube offset from the Raf 3/4" to 11/16". I took towers up to Bond Springs for him to try but silly boy did not take advantage of the opportunity!!!!! LOL :D

Robs rotors with the VR-7 airfoil at the tip would be great for Allans heavy machine with that ej-25 quad cam, but that would require the torque tube offset to be reduced from the Raf 3/4" to 5/8".

Allan is currently flying the 29 footers, with a disc loading that is too high. They are extremely tip dragy at that higher rrpm.

S**t, I did not realise how much testing and work I have done living and operating Rafs for 7 years, to achieve an acceptable level of pitch stability.

The above is a cheap, simple and quite a quick Raf modification. The last one we did in NZ had excellent pitch stability. Stick fixed testing showed very little pitch movement with power changes. :D

IMHO you do not need to lift the cabin. Certainly up 5" to sit the cabin on the keel instead of under it would be all that is required. :)

Geez, better get going to shift that axle back on another Raf!!!! :)

Aussie Paul. :)

[ventana7]

Hey Murray,

I am just now up in Gladstone heading south towards Scarborough in our sailboat. Hopefully I will see you soon and go for a fly. We are leaving the boat here and flying to the US early october so I can buy a gyro and do more flying.

Rob

[joeheli]

Murray Are you going to reproduse that gyro? or You just made it for your self?

[CLS447]

I think that those machines are beautiful! Excellent work!

[murraybarker]

Thanks Paul, I would prefer to pull the whole thing to bits and start again, maybe i'll just tell Allan it was stolen from the hanger and then just bring it back when its finished.He has droped the keel and lowered the engine and tilted it foward(gearbox up) this has helped the thrustline a lot.Plus the big HS you suplied has made it a lot nicer to fly.He is flying on 30* RAF blades again.
Rob, Give me a yell when your are in town.
Leonardo, no I dont plan to make kits or anything like that,there is a twin to the white gyro on the way but with a few changes.