Prop pitch

[StanFoster]

I am going to keep increasing the pitch of my Warp drive to see how much of an increase in cruise I can get. My IvoProp is coming soon and I want to get this data recorded from my Warp drive before I take it off and sell it.

I was running my prop at 13 degrees up till summer. It would consistently get me 80 mph actual cruise speed at 4800 rpm. This again being GPS readouts over two course runs 180 degrees opposite.

As I got into summer...and started hauling passengers...some quite heavy..I reset my prop to 11 degrees and left it there until now. It climbs out much better with two people at this setting and runs around 5300 on climbout....but my cruise speed went down to 72 mph.

I have now set it to 16 degrees and will test fly it tomorrow. This is 3 degrees greater than the 13 degrees that cruised at 80 mph. I will of course not leave the airport if the climb rate is undesirable..

If I feel it can handle another degree...I will do so and take it back up again making sure I have sufficient climb with it.

I will do this for a few more degrees or until I can tell its at its limits.

I think this will be interesting to see how how into the 80's my SH will cruise.

I do not have a manifold pressure gauge yet...so I will be conservative and just make sure my rpm's arent being slowed down too much.

Its going to be nice being able to do this in flight with that new prop.

I will post my findings from time to time as I increase my prop pitch.


Stan

[Fl90]

I was pulling 320lbs. at 6300 w/60" warp on my 503. I changed the pitch from 8 to 10.5 deg, then I had 290lbs. at 6000. My cruise is 5100 and 50-55kts. 4 gal/hr. . I made the change to smooth out engine vibration at cruise.

[CLS447]

Great test Stan !

What is the "official" redrive ratio on the SH ? What is the diameter of your prop ?

Do you know how much pitch change the IVO setup will give ? ( like maybe 10- 20 degrees of pitch?)

I never really used a protractor on my IVO, I just used the tach.

Thanks Stan, have fun !

[StanFoster]

Chris: My prop is 72 inches. My redrive ratio is 2.1

I do not know the pitch range of the Ivoprop....but I am sure that info is coming with it.


I do know that there are pitch limiting washers to control pitch on both ends of the pitch range. I will limit my prop to 5300 rpm on take off....and also have a limit on its maximum pitch. I would not want to be able to pitch the prop so flat that I notice 6000 rpm's on takeoff.:eek:

If you think about it....the prop stays where its at if the the motor or the switches fail.....so I would also not want to be able to pitch the prop so much that I lose my climb....then suddenly find I cant reduce the pitch.:eek:

I know I am going to really like having a higher cruise speed....less engine rpm..less prop noise....and still be able to have a good stout climbout with Jeff onboard as well.:D .....all this with a simple toggle switch.

BTW.....I was told that GBA is testing this prop on the SparrowHawk. I have talked to a few who have really liked it. One of them is Jim Mayfield......that was more than enough convincing for me.


Stan

[asmuzsr]

Stan
Having had one of them I can say that there's a long involved process to setting the limits for cruise and climb. As far as climb is concerned they have you go through certain steps and what you wind up with is a cruise setting that at full throttle still gives you about 200fpm climb just incase.

[StanFoster]

Tony: Thanks for that tidbit of info....

I like the 200 fpm climb rate in case of pitch adjustment failure while running full pitch.


Any idea what the pitch range of the IvoMagnum is?

I am going to try some cruise tests as soon as the weather straightens out in a couple of hours. I have my Warpdrive on 16 degrees right now,....3 degrees more than what I cruise at 80mph/4800rpm with. It will be interesting to see what 16 degrees does...and maybe 17?....18???? I will quit when it either doesnt climb satisfactorily or it feels like I am giving the engine too much.


Stan

[asmuzsr]

Hey Stan
No never checked the pitch setting other than setting it for climb out. I'll say one thing it was cooling watching that little 503 pull me through 90 mph with no sign of slowing down. Had to back off as red line on the plane was 100.
Would put one on the next RAF but if I ever go Sport Pilot I'd hae to take it off. They don't allow in-flight adjustable props. Bummer

[StanFoster]

Tony: After "going through the gears" so to speak yesterday adjusting my Warp drive....I am totally convinced that being able to do that while flying is going to be the single biggest improvement that I can do to my SH.

I want to get my cruise back in the 80's...at a much lower rpm...and still be able to climb out on an 85 degree day with Jeff onboard.:)


Stan

[asmuzsr]

I know it's apples to oranges here, but I cruised at 85mph all the time in my old RAF. I had a carbed 2.2
don't remember the pitch Think it was about 13.

[dragonflyerthom]

Tony

That sounds about right. What RPM were you running around 4200?

[asmuzsr]

Yeah Thom
About 4200-4300 don't remember. Been almost 4years now:Cry: I miss my baby.

[StanFoster]

Tony: My 2.2 RAF also cruised exactly at 80 mph at 4800 as I looked back in my logbooks and checked. I kmow that my SparrowHawk isnt going to be as fast as a like equipped RAF as that big roomy cabin has a penalty to pay. One that I dont mind paying...ha. What I do want though is to get the max out of what I have.

I have to add this....I NEVER go by my ASI...my RAF read around 10 mph too fast at 80...and so does my SparrowHawk. I could easily report 90 mph. cruising speed...but the ONLY speed I record in my logbook is the GPS averaged speed over two 180 degree opposite runs. This is dead accurate..and no disputing any error in the ASI.

I hear reports of gyros going 100...110....whatever. Until I have sat in the seat and recorded GPS readouts going opposite directions...and then average them...thats the only number I am convinced is right.

When I was doing my runs the last two days...my ASI was reading 8-10 mph faster than each one of averaged GPS readings.

Stan.

[gyro]

Stan, what did your SH do when you pitched the blades at 16* your were going to post this info. you also said you might try 17* or 18* as well.

I'm curious as I am looking to get the best performance out of my engine with the righ combination of prop & gearbox.

[StanFoster]

Gyro: Look back at the Prop data thread. I have it all there. I decided to just start another thread on it.

My SH will cruise 72 mph at 4800rpm with an 11 degree pitch.

It will cruise exactly 80 mph at 4800 with a 13 degree pitch.

It will cruise exactly 81 mph at 4550 rpm with a 15 degree pitch.

It will cruise exactly 83 mph at 4550 rpm with a 16 degree pitch.

At 19 degrees...wide open is 4200 rpm. It will cruise 75 mph at 4000 rpm. This I feel is the max as my climb rate was still ok..but it just felt like it was pulling the motor...and obviously it is. My seat of the pants tells me that this was the limit and no more increasing the pitch on this prop.

I was able to maintain altitude at MPRS at 3530 today. I have never had to run an engine that slow.

It will be interesting to be able make all these changes with the touch of a toggle...every flight....

I just want to make it clear that I am not going to just see how fast I can cruise without really knowing what the manifold is doing and monitoring everything else. I can tell that the loafing around is what I am going to like the best....and the reports from ground observers are that my high pitch settings are definately quieter.


Stan

Stan

[asmuzsr]

Stan
Now that I see the rpm's you ran I have to say that mine were 4800 also, like I told Thom it's been along time.
My airspeed indicator was right on. I would cross check it with the gps and there was no difference.
Looking at your rpm's and speed settings I's say your right about the cabin size making the difference between the 2.

[StanFoster]

Tony: I always thought that it takes a 2.5 in the SparrowHawk to keep up with a 2.2 in an RAF. In my case that is exacty what happened. Both cruised 80 mph at 4800 rpm. The 2.5 needed to push that fatter cabin through the air.

But with the variable pitch prop...it will make my SH perform better because I no longer will be flying with one "gear" choice.:)

After all this testing...I hope my Ivo will produce the same results with a "tickle of the toggle". Time will tell.......

Stan

[StanFoster]

Heres the graph for a stock 2.5 FI engine. Can someone explain the lower VE graph?


http://www.protekperformance.com/rv7/engine/dyno_graph.htm



Stan

[dragonflyerthom]

That supercharger sure looked good Stan. An extra 35 HP. Sure looke easy to install also.

[Papa Smurf]

I believe the VE to stand for "Volumetric Efficiency". It's a rating of the engines ability to breathe..A percent of it's theoritical maximum air flow into the cylinders. I think they are trying to show their installations are "getting all available" from the engine.

100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456

Just my thoughts