Perry Mick wrote:

Well, not exactly. After 5 years and 500 hours of direct-drive,
ducted-fan rotary flying, I did a short first-flight around the

pattern

today with a new configuration: RD1B and a prop.

I am used to getting pushed back in my seat when I apply full

throttle

for takeoff. The open prop seems very sluggish while taxiing, and at

the

start of takeoff roll. I can feel the blades "unstall" after building

up

some speed. This is something I never experienced with the ducted

fan. I

saw 5400 RPM on climbout, higher than before (5100). 5400 was max.

level

flight RPM with the ducted fan, so I expect it will go up to 6000

with

the PSRU. I shed 36 lbs. in the propulsion system doing the

changeover,

and had to remove the weather radar indicator from the panel and the

wx

antenna from the nose (additional 16 lbs. combined) to get the cg

back

(radar needs repair anyway, it's just been balast for a long time).
Climb rate is definitely better (higher revving engine, less weight).
I'm hoping to get at least 180 mph in cruise, 155 was about the best

I

could do with the ducted fan.

Perry

Hey Perry finally tried a PSRU. Got some pictures of the prop? Pitch?

diameter?

RD1B is 2.85:1 right?

Paul Lamar

I had considered a 2.85 that Peter Cowan had for sale awhile back, but I

just couldn't make that ratio work on a pusher (on paper), with my "low" rpm
engine (7000 redline).

RD1B is 2.17 six-planet. I actually was not even thinking about putting

on a PSRU at this time, but with the big fad of going to 2.85 among the RV
crowd, a low-time RD1B went on sale by a guy doing

a conversion to 2.85.

For prop I just looked at what the O-235 LongEZ guys were using and

started with that. The average seems to be around 62" in diameter and 68"
pitch, so that's what I analyzed and built. I was going

to make it two-blade, but I had some prop bolts laying around I wanted

to use, that limited prop hub thickness to 3.5". So I hit on the idea of
making it 3-blade with narrow blade chord. I wanted to

keep the diameter small as I have the thrustline lower 2-3 inches from

stock. I have about 11 inches of ground clearance.

I have some vibration that only showed up after bolting on the prop, so

I assume it's a small imbalance in the prop. But I can't get the dynamic
balancing equipment to converge on a solution. That's

why I kept the flight short. I'm going to try again today at a higher

RPM.

I'll try to take some photos with my cheap digital camera.

I still like the ducted fan, someday I'll build this LSA Solitaire,

where the speed limit is 120 knots.

Perry

Hi Perry,

no plans or dreams to put together a different fan for the Eze?
I thought last time I visited your site, that there where plans for a
different shroud and fan?

Good luck with the optimisation process!!

Thomas J.

I think Perry got tired of having all Long Eze guys kick sand in his face :)
I also think he will improve his MPG greatly.

Paul Lamar
 
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