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How much speed will a Sensenich ground adjustable prop add to my RV-6A

Q

quinnjim

Member
I have a metal Sensenich prop on my RV-6A. Thinking about adding a ground adjustable prop from the same company.

If I set it for maximum cruise speed, what kind of true airspeed can I expect from my Lycoming O-320 160hp engine?

My current prop is a metal fixed pitch Sensenich. Not sure of the pitch on that one, but it seems to be a cruise prop.

Not sure if I stand to gain much speed going from a metal prop to a ground adjustable composite one.

Does anyone have a RV-6 setup with this prop set for max cruise??
 
A metal prop can be re-pitched by a prop shop, so that is another option. What speeds and engine parameters are you currently experiencing?
 
If you have a cruise prop, the fixed pitch is always going to be the fastest. The adjustable is just going to give you a range of options.
 
meloosifah said:
If you have a cruise prop, the fixed pitch is always going to be the fastest. The adjustable is just going to give you a range of options.
Click to expand...

I'm actually looking for guys with RV-6's with the O-320 and the Sensenich ground adjustable prop to give me some cruise numbers.

Thanks!
 
quinnjim said:
I have a metal Sensenich prop on my RV-6A. Thinking about adding a ground adjustable prop from the same company.

If I set it for maximum cruise speed, what kind of true airspeed can I expect from my Lycoming O-320 160hp engine?

My current prop is a metal fixed pitch Sensenich. Not sure of the pitch on that one, but it seems to be a cruise prop.

Not sure if I stand to gain much speed going from a metal prop to a ground adjustable composite one.

Does anyone have a RV-6 setup with this prop set for max cruise??
Click to expand...

At lets say at 7500 ft DA, what is your max RPM and what TA speed are you getting now?
 
quinnjim said:
Not sure if I stand to gain much speed going from a metal prop to a ground adjustable composite one.
Click to expand...

Too many variables to compare speeds with another 6A.
Best way to estimate is comparing prop you have with prop you are going to. What is your current pitch and wide open RPM? With fixed pitch, speed increase will be proportional to RPM increase. RPM increase is a function of pitch.
 
I went from fixed pitch to a ground adjustable on my 6A 160hp. My goal was to set pitch for better climb performance than I was getting. I live and fly in the hot flat land south. GA props aren’t a solution for better climb or cruise unless you set it for that purpose. I don’t expect you to see much difference in cruise than your current setup unless you pitch it for a difference eg: better climb(flatter) or better cruise (set it with more pitch than current fixed metal) If more pitch then possibly better cruise , but your takeoff climb will decline, pitch flatter, better TO climb but, lower cruise.

In the past 6 years 760 hrs, 150 kts is what I see. My new ground adjustable gets me to altitude faster, thats how I pitch it, wanted. Good luck. !
 
I flew both props on my 160hp 0320 RV4

quinnjim said:
I have a metal Sensenich prop on my RV-6A. Thinking about adding a ground adjustable prop from the same company.

If I set it for maximum cruise speed, what kind of true airspeed can I expect from my Lycoming O-320 160hp engine?

My current prop is a metal fixed pitch Sensenich. Not sure of the pitch on that one, but it seems to be a cruise prop.

Not sure if I stand to gain much speed going from a metal prop to a ground adjustable composite one.

Does anyone have a RV-6 setup with this prop set for max cruise??
Click to expand...


I flew the 2600 rpm restricted metal.prop.on my rv4 when I first flew it. 81 pitch.
I flew a catto.prop for about 400 hours.
I have flown the senesenich GA prop now for about 400 hours
The metal sensenich and the GA prop have very close performance at 2600 rpm.
If you can live with the 2600 rpm limits stick with the metal prop. It helps with cg and its basically bullet proof low maint. If you need more the extra 100 rpm and money isnt a factor the GA prop gives the abilty to make adjustments.

I wish i had kept the metal prop...it would be on the airplane today.

Cm
 
Total performance in every aspect was very close.

riobison said:
What was the take off and climb performance like between each of them?
Click to expand...

I was racing the airplane and the catto was good for that. The metal prop and the GA prop pitched for best cruise speed perform almost identically. I love the GA prop but it is so light I makes my backseat basically useless for passengers.

The metal.prop is a very good prop IF you dont mind the rpm restriction.
I get the same 165ktas at the same 2600 rpm same fuel burn.

Cm
 
Are you intending to cruise 10 knots short of VNE and above 2600 rpm though?

I came home from Adelaide to Sydney a week ago, 161 KTAS and 6.8 gph, 25ºF LOP @ 65% power 2370 RPM at 7000 AMSL, IO-320, metal Sensenich cruise prop. Very happy with those numbers.

It was smooth air, and I could easily push it up to over 170 TAS by winding-in the red knob until somewhere nearer to 2450-2500 RPM, but then I'd be nearer to 8 GPH and honestly, it's not worth it.

- mark
 
Following

I am following this conversation closely. I think I can get more speed out of my RV if I de pitch the prop. But does one really want to be cruising at 2650 rpm, so close to red line?
 
PilotjohnS said:
I am following this conversation closely. I think I can get more speed out of my RV if I de pitch the prop. But does one really want to be cruising at 2650 rpm, so close to red line?
Click to expand...

Official Lycoming recommeded actions if you exceed redline
https://www.lycoming.com/sites/defa...20Engine%20Inspection%20after%20Overspeed.pdf

To summarize... for most Lycomings, if the overspeed is under 5%, no action needed other than stop doing that. For a 2700 rpm redline, that means you stayed under 2800.

My interpretation (FWIW), it isn't high risk to run at 2690. Certainly don't need to run at 2400 'to be safe'.

That said, I do obey the 75% max continuous power limit. Above 7500' DA its going to be really hard to exceed 75% regardless of rpm.
 
blaplante said:
That said, I do obey the 75% max continuous power limit.
Click to expand...

To be clear, there is no '75% max continuous power limit' for most, if not all, of our normally aspirated Lycoming engines. They are rated to run at 100% power continuously. You can check the TCDS for your engine and it will list the 'max continuous power' limit.

An example from TCDS 1E10, Rev no. 29:

i-7nqcTRx-M.jpg


Lycoming does recommend running at 75% power or less to maximize the longevity of the engine.
 
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2700 rpm all day long to get 75% power depending on Alt. On a long trip and I'm in a hurry thats what Ive done for the last almost 50 yrs.

If for some reason you do go over it wont blow up and the valves won't float.

There are geared lycoming engines that will spin 3400+ rpm and some of them are supercharged.

And yes in smooth air I will run within 10 kts of VNE.

My RV4 was within 3 kts of VNE

There are lots of 4s that are Rockets or Super 6s or Super 8s that routinely cruise over Vans published VNE. Again that is another level of risk that some people do daily.
 
On my 150hp RV-6A, the Sensenich 3 blade in a cruise setting gave me about the same airspeed as my old climb pitched 2 bladed Catto. So I gained no performance in cruise and lost performance in climb. I put about 30 hours on the Sensenich at various pitch settings in a week. Then all the paint started peeling off so I sent it back for a refund and put the old and much better performing Catto back on my plane.
 
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Missed that

RV8JD said:
To be clear, there is no '75% max continuous power limit' for most, if not all, of our normally aspirated Lycoming engines. They are rated to run at 100% power continuously. You can check the TCDS for your engine and it will list the 'max continuous power' limit.

An example from TCDS 1E10, Rev no. 29:

i-7nqcTRx-M.jpg


Lycoming does recommend running at 75% power or less to maximize the longevity of the engine.
Click to expand...

So i missed the 75% recommendation. I am already at 80%+ in cruise below 7500’.
I had Catto make a prop for me optimized for high altitude cruise. He recommended the three blade because he said it is better than a 2 blade up high. I was thinking it was over pitched, but after reading these posts, I feel much better at keeping my prop the way it is. The plane has a comfortable cruise rpm, not screaming at 2700 rpm, but still can maintain 300’ per minute climb at 16500’ at reasonable speed (125+ kts true)
 
Christopher Murphy said:
I flew the 2600 rpm restricted metal.prop.on my rv4 when I first flew it. 81 pitch.
I flew a catto.prop for about 400 hours.
I have flown the senesenich GA prop now for about 400 hours
The metal sensenich and the GA prop have very close performance at 2600 rpm.
If you can live with the 2600 rpm limits stick with the metal prop. It helps with cg and its basically bullet proof low maint. If you need more the extra 100 rpm and money isnt a factor the GA prop gives the abilty to make adjustments.

I wish i had kept the metal prop...it would be on the airplane today.

Cm
Click to expand...

Great information. I do wonder about repairing nicks on the compost prop too. I may just stick with what I have.
 
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