Author Topic: Prop Pitch (Read 2708 times)

Ghosth · « **Reply #15 on:** July 18, 2000, 09:15:00 AM »

Sparks, look for the RPM Gauge. Ussually next to Man gauge.

True we do not have pitch lever that I've seen.

(I'm busy learning most of this stuff same as you guys. Trying hard to stay half a jump ahead)

Ash · « **Reply #16 on:** July 18, 2000, 09:54:00 AM »

I played with the pitch and RPMs last night for awhile. At 25K, I chopped my MP to 25 in, then varied my prop pitch to maintain 225 mph. I think pp was approx. 22 rpm. I was able to keep my G10 in the air for what seems to be a much greater time than usual < was hunting Buffs w/DT >. I'll do some more testing later this week and I'll keep you posted.

Sparks · « **Reply #17 on:** July 18, 2000, 12:41:00 PM »

Ghosth -
Done some offline testing myself now and see it is working as I would expect - will definitely help cruise performance but will have to be carefull to go fully fine before engaging in combat.
I wonder what the best setting for diving is ??

Ripsnort · « **Reply #18 on:** July 18, 2000, 12:48:00 PM »

So, for fuel conservation, should one adjust BOTH RPM and MP? Or just RPM?

Ash · « **Reply #19 on:** July 18, 2000, 01:32:00 PM »

My initial testing indicates using both for cruising and fuel economy. I would think adjusting just your MP will be more effective than just adjusting PP. Combine the both and I think you can get some "legs". I also read somewhere that IJN pilots set some tremendous distance records before the war by varing just PP and MP.

OTR,
Ash

Rocket · « **Reply #20 on:** July 18, 2000, 01:38:00 PM »

Rip,
One should adjust both for fuel savings. In the Hog I set at about 21-2200 RPM and 30-35 MAN for best savings. I fiddle with it until she will stay level but just above the speed she wants to nose down. And can fly forever on those settings

Remember you just have to play with it a bit at different speeds and alt. The MAN and RPM will vary and will vary with loadout options

S!
Rocket

Ripsnort · « **Reply #21 on:** July 18, 2000, 02:03:00 PM »

Thanks Rrrrrrocket! Ash!

Ghosth · « **Reply #22 on:** July 18, 2000, 09:37:00 PM »

I've noticed that settings also vary a lot from plane to plane.

What works fine for the 190A5 (can maintain 300 TAS easily)seems to leave the Yak stalling out.

I suspect that altitude plays a part as well.

Sparks · « **Reply #23 on:** July 19, 2000, 05:55:00 AM »

Rip
Done more experimenting - you definitely need to adjust both for cruise or descent but it depends on altitude and to an extent on your current airspeed.
For example I flew a Spit at about 220 kts and got it level - set MP to about 35 (if I remember and coarsened the prop off to reduce RPM to about 2000. Airspeed didn't change - if anything started to fall. However did the same thing from 280 kts and it climbed to 285. Lesson is airspeed will impact the effiency of the prop to produce thrust beecause as airspeed increases the angle of attack of the prop blade to the airflow decreases - so if you make the prop pitch too coarse too slow then the blade will approach the stall and become less efficient and thrust will fall.
From what I've tried it appears to work very close to RL in that you choose a coarser pitch (lower RPM) the faster you go and go to fine for climbing and slow speed.

I would be interested to know if anyone has done any acceleration comparisons for a shallow dive condition say from 300kts and above to see if pays to coarsen the prop off a bit as you dive away to break off.