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Whirlwind GA200L

Rick RV-4

Well Known Member
Any new PIREPS on the Whirlwind ground Adjustable GA200L prop? I've read the other threads, but looking for any new info on performance, satisfaction, etc. Haven't seen any recent comments . . .

I am currently flying w/ a Sensenich metal/O-360 combo. Happy with the performance but hate the vibration . . .

Also considering a Catto, but like the idea of tweaking it for higher pitch for longer cross country missions.

thx,

Rick
 
I'm happy with my WW 200GA

I now have 30 hrs on my WW GA prop. I have adjusted it 3 times and believe I have found the best pitch for my setup. I am running an IO-320 which produces 165hp. The prop climbs at 2000++fpm solo with full fuel. At cruise a can meet or exceed vans performance figures. At 4000' DA I can cruise at 160kts, up higher even better. I replaced a sensenich FP prop which had a 2600 rpm limitation. This prop can spin up to 2700 allowing me to take advantage of the high end if I want. I think that it really achieves more than the typical compromise one makes with a FP prop. It performs extremely well in all phases of flight.
 
Repitch question

Thanks Mark!

So how long does it take you to do a re-pitch of your prop? I don't see adjusting it too often, but I'm curious as to how long it takes you.

Also, what about noise levels and vibration?

Thanks,

Rick
 
Time required to re-pitch WW200 GA

Good question. One of the benefits of the WW GA prop is the ability to set pitch freely between the range available - this is also one of the challenges. Setting pitch can take from 15-30 minutes depending on how lucky you get. I use a modified pitch tool with the digital level to get the blades within 0.1* of each other. This takes trial and error because you want to maintain the correct (chosen) pitch. If the bolts are too loose when setting pitch, when you tighten them down the pitch may change slightly - then you must loosen them up and check both blades again. Once you get one side done - rotate prop 180 and do the measurement always on the same side on the aircraft. This is the only way to determine how they are truly oriented to each other. Having done it 3 times I know the routine - now that I have it dialin in where I want, I don't plan on changing it. However will have to check during recommended inspection. A pain, but worth it given my performance.

Regarding noise or vibration . . . no appreciable noise difference (need to ask folks on the ground - but they say it sounds great). Regarding vibration - the only slight vibration I notice is when i reduce power on approach. It occurs when the prop spins down as I decrease throttle form cruise phase to approach speed - it is felt as I go through 1540-1510 rpm. Nothing too bad, just a slight, but noticable vibration for a brief period passing thru this rpm range. Approach is the only period of flight that I am in this range - nothing noticed on spin up - so i can live with it.
 
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Mark,

My setup is very similar to yours... RV9A / IO-320. What pitch did you finally end up with, and what static RPM were you seeing? Also, what source have you found for the lock washers, or can they be torqued/used more than once?
 
Me too

I have 110 hours on my Whirlwind. It's in a 150 HP RV4. I don't have comparison data, but I am satisfied with the performance of the prop so far.

Mark's comments are accurate with regard to changing pitch. It's a little tricky, and you can't be certain of getting it adjusted right on the first try. It's more of a "guess and check" process. The pitch gauge tool provided with the prop allows some variability in position if not used very carefully, but it's simple, and it does get the job done.

I have reused my lock washers, but I have found that after 2-3 adjustments, they lose a lot of their "snap", so I have ordered replacements from Whirlwind.

I have been surprised by how much performance you can gain by changing pitch just a half of a degree. It's nice being able to achieve optimum cross country performance by hitting the "sweet spot" of 2700 rpm/WOT at 8500. Climb performance is great, and I can fly in the rain all day long with no ill effects. Overall, I'm very pleased.

It's worth noting that the spinner is top quality as well. Fit and finish is perfect right out if the box.

M
 
Recommended Pitch angle IO360

I started with whirlwinds recommended 20deg, exceeding 2700 wot and level. My io360 is supposed to be making 188hp. Does anyone have this setup and is 22 deg too much of a change?

I put 2 more degrees of pitch on it and think its about perfect. 2600-2650 WOT @ 7500. And still takes off quicker than I'm used to.
 
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Seems like a big change.

I don't really have a good justification for it, but I would probably try a maximum of 1 degree change and see what that does. One degree can make quite a difference.

A couple of tips:

1) Be sure to evaluate your adjustments by flying at the same density altitude for each trial.

2) By consensus, the ideal cruise setup for fixed-pitched RVs is to have the engine turn at 2700 RPM at 8000' density altitude at full throttle. With this setup, you can easily exceed redline at low altitudes, so use caution. On my 150hp -4, I definitely have more than 20 degrees pitch to achieve this, and my static RPM is on the low side, maybe 2050. Climb performance on hot days at gross isn't stellar, but it's still way better than a 172.

3) whenever changing pitch, check static RPM on the ground before takeoff. An unusually low RPM or vibration in the static run-up could point to problems and save you the indignity of being unable to climb.


M
 
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