"Normal" Static RPM's (New Pilots Read Before Flight!)

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Schmleff

I like Ninjas and Cake
Joined
Jan 2, 2006
Messages
2,657
Location
Oshkosh, wi
*THIS LIST COULD SAVE YOUR LIFE*

In light of the recent Sonerai crash I am starting this thread to help people that are new to VW engines and props determine what may be considered "normal" power output. It is impossible to truly determine power output by static rpm's, but if the prop size and manufacture are listed with the rpm, we can at least establish some sort of a baseline.

Be careful to read this with caution. What may fly a Sonerai I may not fly a Sonerai II with a passenger. No two aircraft are alike. Even different Sonerai II's may have dramatically different drag characteristics. By no means is it intended to be a "fly" or "no fly" list. It is offered to throw up a red flag for someone that sees numbers lower than listed. It is offered as a safety precaution only.

If John had had such a list available to him, he may have seen that 3000rpms static on a Sterba 54x44 with a 2200cc engine was abnormally low. When I had spoken to him by phone during the preceding week, I asked what his static rpm was. He had not been able to do a full power static run up at that point. I do not fault him or not knowing this information as there was no way for him to know what "normal" should have been.

Please list only documented numbers. Please list them in this format:

Aircraft: Which Sonerai
Fly with passengers: Yes or No
Gross Weight: 0000
Engine: VW 0000cc's, bore x stroke
Carb: Whatever carb used including throat size
Prop Manufacutre: Whatever
Prop dimensions: diameter x pitch
Prop alterations from stock: did you cut the tips? How much
Static RPM: 0000

Please be as accurate as possible. I will edit your entry for clarity if I see the need.
 

splischke

Scott Plischke Sonerai IIL N994SP
Joined
Dec 28, 2005
Messages
1,743
Location
Amarillo, TX
Re: "Normal" Static RPM's

Aircraft: IIL
Fly with passengers: Yes - Little/light ones.
Gross Weight: 1150 declared but realistically 950 lbs at my altitude.
Engine: VW 2180cc, 92mm x 82mm
Carb: Ellison EFS-2
Prop Manufacture: Sterba
Prop dimensions: 54x48
Prop alterations from stock: None
Static RPM: 3280
 

Schmleff

I like Ninjas and Cake
Joined
Jan 2, 2006
Messages
2,657
Location
Oshkosh, wi
Re: "Normal" Static RPM's

Aircraft: Sonerai I
Fly with passengers: NA
Gross Weight: 800lbs
Engine: Factory Aerovee, 1850cc, 78x88
Carb: Aerocarb 29mm (at a 15 degree angle to Y manifold)
Prop Manufacture: Sterba
Prop Dimensions: 54x44
Prop Alterations: None
Static RPM: 3000

Aircraft: Sonerai I
Fly with passengers: NA
Gross Weight: 800lbs
Engine: Factory Aerovee, 1850cc, 78x88
Carb: Aerocarb 29mm (at a 15 degree angle to Y manifold)
Prop Manufacture: Sterba
Prop Dimensions: 52x44
Prop Alterations: 1" removed from tips
Static RPM: 3200

Aircraft: Sonerai I
Fly with passengers: NA
Gross Weight: 800lbs
Engine: Factory Aerovee, 1850cc, 78x88
Carb: Aerocarb 29mm (at a 0 degree angle to Y manifold)
Prop Manufacture: Sterba
Prop Dimensions: 52x44
Prop Alterations: 1" Removed from tips
Static RPM: 3400

Aircraft: Sonerai I
Fly with passengers: NA
Gross Weight: 800lbs
Engine: Factory Aerovee, 1850cc, 78x88
Carb: Aerocarb 32mm
Prop Manufacture: Sterba
Prop Dimensions: 52x44
Prop Alterations: None
Static RPM: 3400

Aircraft: Sonerai I
Fly with passengers: NA
Gross Weight: 800lbs
Engine: Factory Aerovee, 1850cc, 78x88
Carb: Aerocarb 32mm
Prop Manufacture: Sterba
Prop Dimensions: 51.5x50
Prop Alterations: Cut down from 54"
Static RPM: 3250

Aircraft: Sonerai I
Fly with passengers: NA
Gross Weight: 800lbs
Engine: Factory Aerovee, 1850cc, 78x88
Carb: Aerocarb 32mm
Prop Manufacture: Sterba
Prop Dimensions: 49.5x50
Prop Alterations: Cut down from 54"
Static RPM: 3350
 

privatepilot03

The guy with the Rear Drive VW
Joined
Jan 11, 2007
Messages
359
Aircraft: Sonerai IILS
never flew with passengers B4 I sold it
Gross weight: 1150
Engine: 2332cc rear drive (84x94)
Carb: 32mm aerocarb (no carb heat)
Prop: Sterba
Prop Dims: 52x54
Alterations: 1" removed from each prop tip (was 54x54)
Static RPM: 3250ish
 

Soneraifred

N99FK and me at OSH
Staff member
Joined
Jan 12, 2006
Messages
896
Location
Franksville, WI
Aircraft: Sonerai IIL
Fly with passengers: No, but occasionally fly at gross weight
Gross Weight: 925 lbs
Engine: VW 1807cc's, 87mm bore x 76mm stroke
Carb: HAPI UltraCarb (slide-valve, float-bowl, modified Lectron) 32mm
Prop Manufacture: Sterba
Prop dimensions: 52"diameter x 40" pitch
Prop alterations from stock: Originally supplied as a 54 x 42, reworked by Ed
Static RPM: 3150
 

Norm

New Member
Joined
Feb 1, 2006
Messages
4
Aircraft: Sonerai IIL
Fly with passengers: Not yet, still flying off restricted hours.
Gross Weight: 950 lbs
Empty Weight: 535 lbs
Engine: VW 1700cc's, 69mm stroke
Carb: 29mm Posa with owner made needle
Prop Manufacture: Owner manufacture
Prop dimensions: 52"diameter x 51" pitch, RAF 6 airfoil, pitch measured from flat bottom of blade
Static RPM: 2950
 

Chuck in Indiana

Well-Known Member
Joined
Feb 27, 2007
Messages
219
Aircraft: Which Sonerai Sonerai 2L
Fly with passengers: Yes
Gross Weight:950
Engine: VW 1835cc's, bore x stroke 92MMXstock stroke
Carb: AeroCarb 29mm
Prop Manufacutre: Ed Sterba
Prop dimensions: diameter x pitch 54-42
Prop alterations from stock: did you cut the tips? No
Static RPM:3200
 

Bil438

Well-Known Member
Joined
Oct 17, 2007
Messages
777
Re: "Normal" Static RPM's

Aircraft: Sonerai II LS S/N 0072
Fly with passengers: No
Gross Weight: 900 solo
Engine: Jabiru 2200a, 2200CC rated at 80 hp
Carb: Bing 32 mm
Prop Manufacutre: Sterba
Prop dimensions: 54 X 48
Prop alterations from stock: No Prop mods or changes
Static RPM: 3100.
Climb: 3000-3100.
Max RPM: 3300
Bill Evans
FWIW I get airborne about 70 mph and use about 1200' of runway.
 

EricM

Well-Known Member
Joined
Mar 8, 2006
Messages
380
Location
Ukiah. CA
Aircraft: Sonerai II midwing
Fly with passengers: No
Gross weight: 925 lbs
Engine: Revmaster 2074cc 78x92
Carb: Revflow 34mm
Prop: Ed Sterba 54x48
Prop alterations: None
Static RPM: 3100
Climb RPM: 3000-3100
Cruise RPM: 3100-3200 @ 20-22" MP
 

crcfi6303

Active Member
Joined
Oct 20, 2008
Messages
30
Being new to the list I hope all will take my post with a grain of salt. I would not try to fly again with an unknown until I performed a thrust gauge test and checked the foot punds of thrust available in my given example. Culver Propellers (Valley Engineering) and a couple other sources have gauges and detail how to make your own. Using it is as simple as chaining the tailwheel up to it and static running the engine while a second person reads the gauge. I tried to go by static readings for the KR2 that I first tested and because I did not know that my Westach was off, I thought I was good for an initial flight. During takeoff it was apparent that a 100 to 200 feet per minute climb rate was insufficient. It did not help matters that I lost the airspeed indicator on climbout so had to use wind sound and attitude to fly the remaining pattern. I went through 3 more props before finding a 52 x 42 Otto prop that really brought the plane alive with its 1915cc VW. It delivered 1000 fpm climb solo and 750 at 1100 gross weight. I realize that the KR2 has a RAF48 wing so it is definitely a different flying plane but it appears that some of the operating parameters are similar or the same. I would not have flown with an oversized prop had I used a gauge and read the volume of thrust it was making, knowing that it seems that one constant for small 1 and 2 seat planes is at least 200 to 225 pounds of static thrust in order to consider a takeoff and evaluation of a particular engine and prop combo. I realize that over generalizations have as many exceptions as compliance, but as was put earlier, anything that helps us be safer is worth it. IMHO. Thanks for reading. Looking at a Sonerai 2L for me and the wife.

Colin Rainey
Daytona Beach, FL
 

phzabriskie

Well-Known Member
Joined
Jan 18, 2006
Messages
2,255
Location
Santa Fe, New Mexico
Thanks for the comments Colin welcome to the group. The thrust gauge sounds like a simple enough insurance policy to invest in. I had not heard of it. Glad to know of it. ;)
-Pete
 

grostek

Member
Joined
Oct 8, 2007
Messages
6
crcfi6303 said:
Thanks for reading. Looking at a Sonerai 2L for me and the wife.

Colin Rainey
Daytona Beach, FL
Hi Colin,

Thanks for the post, very good advice given.
I have a few questions,
1 Can you maybe point me in the right direction for a thrust meter I can build myself.
2 Did you ever get the KR2 to perform as a two seater?


Kind regards.

Gunter Rostek.
 

Rog

New Member
Joined
May 24, 2009
Messages
2
Hi Guys,
Although I am new to this web sight, I have been flying a Sonerai IIL since 1989. About 5 years ago a storm blew hanger door in on the plane and damaged one wing. I built new wings with a Ribblet 35A415 airfoil and home made Hornier tips. Each wing is two feet longer, and the tail is now nine inches taller than stock. I run a 2180cc VW. I had a Warnke 52X42 and it worked well, but cracked coming home from Oshkosh to years ago. I currently run a Sterba 54X45 but it is too much prop. He is currently making me a copy of my Warnke. If you want to haul two people I recommend the Ribblet wing, I loose very little speed and it hauls me and my fellow lard but buddies with ease
 

thomefran

Well-Known Member
Joined
Oct 8, 2010
Messages
488
Aircraft: Which Sonerai Sonerai II LT
Fly with passengers: No
Gross Weight:950
Engine: VW 2165cc's, bore x stroke Don't know yet
Carb: Zenith
Prop Manufacutre: Ed Sterba
Prop dimensions: diameter x pitch 54-50
Prop alterations from stock: did you cut the tips? No
Static RPM:3040

I'm new to the Forum but I do think this is a very good thread. Especially for us new to the Sonerai. I really love the way my II LT performs. Thanks
 
A

Airskip.2010

Guest
Aircraft: 2L
Fly with passengers: Haven't flown, yet
Gross Weight: 1150
Engine: VW 2180cc's, bore x stroke 92x82
Carb: Revflow 34mm
Prop Manufacutre: Sterba
Prop dimensions: 54x48
Prop alterations from stock: None
Static RPM: 3400
 

Gaston

Well-Known Member
Joined
Mar 7, 2006
Messages
1,111
Hi Airskip

I know that static performance may vary depending on actual temp conditions but turning a 54 x 48 prop at 3400 rpm on a 2180 seems a little high to me...
most probably a healthy 2180,in warm air,could do it,I don't know...

I do not say it can't be done,I only warn you that your RPM gauge may be wrong...Or your prop pitch may not be 48"

the good point is that you may have a very good 2180,that's great

PS.I once compared two supposedly identical prop,from the same source,and found out they were really different in pitch and
they both were stamped 54 x 40
the difference in performance (both 1834 engines were built by me, and identical in every point) was so big that I modified mine to as near as possible the pitch on Brunopitts's prop...

then my 1834 came to real life..

here's some food for thought...

Gaston
 

eschrom

Well-Known Member
Joined
Jan 18, 2006
Messages
760
Location
Harrisburg, PA
My configuration is similar to Airskip's except for the carb:

Engine: VW 2180
Carb: Aerocarb 32 mm
Prop manufacturer: Sterba
Prop dimensions: 54x48
Prop alterations from stock: None

Static RPM: 3350 (measured with a Tiny Tach)

This was measured in the autumn of 2009 on what was probably close to a standard day (68 F). The intake manifold is a 'Y' configuration and the carb is aligned so the needle travels on the a/c centerline. However, I've never been sure that the needle setting is optimized for WOT and I plan to check it again after installing an air/fuel gauge.

Ed
 
A

Airskip.2010

Guest
Thanks, Gaston, and I was thinking it was high, because all I had heard prior to my tesing was to look for 31 to 3200 for a good combination. But, I have also had those that said it is ok.

It was measured with a Tiny Tach, as well, which I am not sure I am happy with. I plan to purchase a hand-held to verify with, and more than likely do thrust tests before hopping in in a serious manner.

Skip
 

Gaston

Well-Known Member
Joined
Mar 7, 2006
Messages
1,111
Don't get me wrong Skip
I'm not saying it is High ,I just meant that I was surprised that a 2180 could reach 3400 rpm Static while turning a 54 x 48 prop.which is a considerable load.

if it does ,great,all is good lucky you...
PS I wouldn't trust a tiny tach as a measuring device for that purpose,using a tiny tach as a reference for our casual flights is another story...

Keep in mind that the engine must reach the rpm at which the HP was rated at,otherwise forget it...You only have partial power available to spin the prop...

I guess I'm getting off thread... sorry

Gaston
 
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