New RAF 2000 build

Loving this thread 👌 when a man builds and works on his gyro I enjoy training him 🍺 will be checking in here regularly, loving the enthusiasm and support
if it was SA the guys would be moaning and bad mouthing the project ….as we know locally if you don’t drive a Porsche and fly a Cavalon your just a dick !
For the record the cavalon is just not my thing ( yes I’m instructor rated on it so I can have an opinion 🤪) personally I like all the hardcore adjustments and easy to fabricate goodies on the RAF 👍
 
Do the drop keel mod!!!

The horizontal Stab does little to stop a power pushover ( bunt )

The H stab's main purpose is to make the gyro less sensitive in pitch, to help you to avoid PIO which can lead to unloading of the rotor, and the resulting PPO. Think of the H stab as the shock absorber on your car, or a damper on a screen door... It is just to Dampen the action of whatever it's used on

The drop keel mod will lower the engine ( which is not ideal ) which in turn lowers the prop ( which IS ideal ).

The BEST thing you could do would be to raise the cabin higher, and find a different reduction drive that places the center of the prop BELOW the engine rather than above it. These mods would give you centerline thrust and would make PPO nearly impossible. Obviously, a new Redrive, and moving the cabin higher are both expensive and major modifications... Doing the drop keel mod is actually a very easy and inexpensive mod that although won't be a complete cure for the imbalance in the gyro, it will be a step in the right direction.

I have seen where some builders mount the radiator above the engine, even the battery as well.... Anything you can place higher than the prop helps with the thrust offset.
 
I wondered if the D-Motor would be a good solution on RAF's. No redrive necessary so the motor could stay put but the prop ends up a lot lower.

Also, has there been any discussion (or calculations by those more knowledgeable) on angling the existing motor so its slightly down at the front. A very small angle change would represent quite a change in thrust line, but then could the mast still be positioned correctly, cg attained etc etc
 
I wondered if the D-Motor would be a good solution on RAF's. No redrive necessary so the motor could stay put but the prop ends up a lot lower.

Also, has there been any discussion (or calculations by those more knowledgeable) on angling the existing motor so its slightly down at the front. A very small angle change would represent quite a change in thrust line, but then could the mast still be positioned correctly, cg attained etc etc
.

I agree on the angle .... Cierva tilted his engine to position thrust line where he wanted ... in his case it was a tractor but same idea you mentioned

.
cierva thrust line.JPG
 
For an engineer, it is important for the propeller thrust line to pass through the CG.
Since most modern gyroplane designers are stylists and not engineers, it is no longer important.
 
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Bensen angled the McCulloch down at the front end by, IIR, 3 degrees. No telling if this was to improve prop clearance or more nearly to to line up the thrustline with the CG.

Vancraft went its own way, angling the engine the other way (aft end down) to "direct propwash onto the H-stab". Hmm.

FW planes sometimes have high thrustlines, IF dictated by the mission. For example, amphibs like the Lake have mile-high thrustlines, to allow the tail boom to clear the prop. But they have big, immersed H-stabs with substantial negative incidence to help with the pushover tendency. This, of course, adds drag, but the drag is the price we pay for the Lake's (very cool) mission. I wouldn't pay that price for the sake ONLY of styling or a seat that's supposedly easier to get into.

On the latter point, sign up for some tai chi and limber up.
 
Vance,

The drop keel allowed the ability to lower the engine and reduce some of the high thrust line by 6 inches.

Wayne
Very interesting. Is there any pdf file to get plans to do this keel drop? Your HS seems great, have made it yourself? If not, where did you got it?

Thank you

Rene
 
Hi Vance, as Wayne mentioned above and as I understand its lowering the line of thrust (with respect to the machines vertical centre of gravity). When researching the RAF mods I found there were actually quite a number of these machines over here in NZ, and a number of them have had the keel drop done with pilots having before and after experience. I have not been able to find or talk to all of the owners yet, but of the ones I have the general consensus seemed that the RAF in its original setup was overly sensitive to wanting to nose over with any light g's and power, and it became a more predictable machine to fly with the mod done.

I of course wont have before and after experience to comment on as I am doing the mod at the start, but you try and make the best informed decision you can when building experimental aircraft like this. That blue machine in those photos above will be one of the RAF's over here in NZ, and the red one in the attached photo is local to me. I am only dropping the keel by 4", it appears most do a 6" drop, and I have seen mention of machines overseas doing an 8" drop.

GaryView attachment 1152097
Beautyful machine. The HS looks great. Have you made the HS yourself?
 
Howdy all! Just a quick update on the project. Engine was inspected, cams ground, and all looked great and she’s now where she should be. The muffler had a lot of surface rust so after getting that taken care of it was installed. The upper dash mount is cut and ready for install when ready. Looking into moving the mains back. sounds like a weekend project. Hope everyone is well. Happy holidays!
 

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Looking good. Something worth checking that I found in my assembly, check the gusset at the bottom of the dipstick tube where it goes into the sump isnt sitting against the engine mounting frame.
 
Looking good. Something worth checking that I found in my assembly, check the gusset at the bottom of the dipstick tube where it goes into the sump isnt sitting against the engine mounting frame.
Thanks Grevis I’ll take a look at that
 
Dash pod is cut and ready for install!
 

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Hey y’all I’ve moved my main gear back, and am beefing up the landing struts some. I’m debating using a heavy duty motorcycle off road rear shock and keeping the tubing the same 1”, or upgrading to a larger tube, beefier hardware and a larger shock. Any suggestions? If I upgrade, thinking to a 1.5” OD 1.25”ID tube with larger shock. I will need to know where to find rod inserts for the 1.25” ID and 1/2“ bolt, and also 1/4“ bolt. If I keep the rods the same, where can I find fork style 1.25” male fork ends with 1/4” bolt to mount the shocks. Been looking around maybe I’m looking for the wrong thing?

Mike
 
I'm experimenting with some suspension in my RAF restoration/build too. Im going to try a pair of lovejoy runright torsion units mounted below the motor. That will allow me to use all the existing RAF parts including the struts that went up to the mast.

If I was replacing tubing I would probably look to see if there are some extruded profiles around that may be more aerodynamic.

Gary
 
I'm experimenting with some suspension in my RAF restoration/build too. Im going to try a pair of lovejoy runright torsion units mounted below the motor. That will allow me to use all the existing RAF parts including the struts that went up to the mast.

If I was replacing tubing I would probably look to see if there are some extruded profiles around that may be more aerodynamic.

Gary

interesting Gary. I’m just getting frustrated at not being able to find rod end inserts for the larger tubing or the 1” opening Clevis mounts for the shocks I currently have. I know exactly how I can do it either way but can’t find the parts.
 
Any engineer with a lathe should be able to make up some inserts for a larger tube to take the original rodend.

For clevis mounts if you cant find anything at places like aircraftspruce, then maybe businesses that deal with hydraulic or pneumatic cylinders would be worth a try. (or just get an engineer to make some)
 
Any engineer with a lathe should be able to make up some inserts for a larger tube to take the original rodend.

For clevis mounts if you cant find anything at places like aircraftspruce, then maybe businesses that deal with hydraulic or pneumatic cylinders would be worth a try. (or just get an engineer to make some)
Good idea. I will check with Kolibri he is very knowledgable and has been a great help so far!
 
Assembled and installed the new duel fuel pumps. Attempted to install them in the location as shown in the Manuel, but due to the relocation of the main gear, it didn’t seem to fit properly And was interfering with the cyclic to rotor control. I opted to mount them behind the new gear on the keel. Seemed to work out fine. Anyone have any ideas or problems with it Mounted in this fashion? seems like it will function just fine in this location. Something I’m not seeing maybe? Appreciate all your comments!
Mike
 

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That should work. If you want another idea I tried using the 2 original mounting holes for the landing gear, and put a pump sized p-clip in both (so 2 clips per pump), but had the 2 clips opposing each other. This allowed the pump to go in at about a 45degree angle pointing aft at the bottom of the pump. The hose out the top goes up to the cabin wall, well clear of the control rods, and I tee'd them together up by the motor.
 
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