VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #31  
Old 05-30-2018, 10:32 AM
springer springer is offline
 
Join Date: May 2012
Location: AZ/MN
Posts: 299
Default

Quote:
Originally Posted by smokyray View Post
However comma, nobody mentioned the Catto Gen 3, Performance (wood) 3 blade "almost constant speed" and Whirlwind GA.

It's EW was exactly 1000lbs. Flight qualities and performance were superb and had my favorite "light nose" feel.

The CG and performance/handling on light, IO-360 powered SBS RV's with a FP prop out front is superb. I have always considered fuel as my greatest ally in CG adjustment over the years as it's forward of the CG for a reason. More baggage? Add fuel. Local flying/Aerobatics? Less. Keep it light, less than 1/2 fuel is plenty.

V/R
Smokey
Well said Smokey!
__________________
Jim
RV-4 '88-'09 Built & Sold
RV-8 Purchased
Reply With Quote
  #32  
Old 05-30-2018, 11:52 AM
Reaver Reaver is offline
 
Join Date: Sep 2017
Location: Claremont, CA
Posts: 25
Default

Quote:
Originally Posted by smokyray View Post
The CG and performance/handling on light, IO-360 powered SBS RV's with a FP prop out front is superb. I have always considered fuel as my greatest ally in CG adjustment over the years as it's forward of the CG for a reason. More baggage? Add fuel. Local flying/Aerobatics? Less. Keep it light, less than 1/2 fuel is plenty. Additionally, I have flown both my FP prop RV's off my 1200' grass strip with no worries and have had no problems keeping up with any similarly CS equipped RV's. Where the FP really shines is aerobatics (and dog-fighting is so inclined). I prefer a lighter nose and less flywheel effect and had all my props pitched slightly climb oriented where I could obtain 2800 (or greater) RPM WOT at Sea Level. This allowed me to run WOT at 11,500' at 2650 RPM and enjoy 175KTAS and maintain the age old "48" combination of MP and RPM.
This will be almost my exact setup: keep it light, only prime the parts that need to be primed, IO-360 (180hp) and a Catto FP prop. The main difference is that I'll be using the RV7 more for XC flight than aerobatics; just the occasional light roll, etc. What was/is your fuel burn at that 11,500' and 2650rpm WOT? I was just assuming that I would want a cruise pitch, but am open to being convinced otherwise.
Reply With Quote
  #33  
Old 05-30-2018, 12:52 PM
Raymo's Avatar
Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 1,645
Default

Quote:
Originally Posted by Reaver View Post
This will be almost my exact setup: keep it light, only prime the parts that need to be primed, IO-360 (180hp) and a Catto FP prop. The main difference is that I'll be using the RV7 more for XC flight than aerobatics; just the occasional light roll, etc. What was/is your fuel burn at that 11,500' and 2650rpm WOT? I was just assuming that I would want a cruise pitch, but am open to being convinced otherwise.
I don't often cruise that high or that RPM, but at 8500-9500 MSL, 2500 RPM, I burn 7-7.5 GPH at 155 KTAS with my Catto 3 blade prop (MFG in 2016). Other details in my signature.
__________________
Ray
RV-7A - Slider - N495KL - First flt 27 Jan 17
O-360-A4M w/ Catto 3 blade NLE, AFP FM-150 FI, 1 PMag, Vetterman Trombone Exh, SkyTech starter,
PlanePower Alt, FlightLines Interior, James cowl & plenum
All lines by TSFlightLines
NSDQ

"The object of the game, gentlemen, is not to cheat death: the object is not to let him play."
Patrick Poteen, Sgt. U.S. Army

Last edited by Raymo : 05-30-2018 at 02:28 PM.
Reply With Quote
  #34  
Old 05-30-2018, 02:05 PM
smokyray's Avatar
smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,697
Default Ultimate Seven....

Quote:
Originally Posted by Reaver View Post
This will be almost my exact setup: keep it light, only prime the parts that need to be primed, IO-360 (180hp) and a Catto FP prop. The main difference is that I'll be using the RV7 more for XC flight than aerobatics; just the occasional light roll, etc. What was/is your fuel burn at that 11,500' and 2650rpm WOT? I was just assuming that I would want a cruise pitch, but am open to being convinced otherwise.
Reaver,
I've been flying FP props on RV's for a long time. Performance observations involved many hours of flight testing, traveling and tweaking. (by definition, every flight in an EXP is a test flight)
Higher RPM at low altitude with a capability to achieve rated RPM at high altitude was always the better call as desired overall performance at lower altitude was achieved as well.

A parallel valve LYC IO-360 is rated at 180HP at 2700RPM, engine mods, high comp pistons and blueprinting notwithstanding.
Inflight, to achieve higher TAS you need to fly higher, therefore a good FP prop will allow you to run wide open above 10,000 feet. For Carbs that's good as the carb throat is most efficient with the butterfly valve (throttle control) streamlined in the slipstream. For fuel injection the same efficiency applies, especially cold air induction.

The Ultimate RV7 I delivered for the South African customer had a digital engine monitor and as I noted in my logbook, "RV7 with lots of Sevens!" 7.7GPH at 177 KTAS 50 LOP at 11,500 2700 RPM. The builder had excellent attention to detail and weight awareness and it was readily apparent inflight.
Additionally the Rod Bower Cold Air induction really worked well as did the San James fairings/plenum.*

It's fast.*


Ultimate Seven

V/R
Smokey

* My own RVX with Carbureted 0-360J, home made aluminum plenum and fairings and prototype Catto Gen 2 Two blade will match those speed/altitude numbers, but at a higher fuel burn, around 9GPH. Hard to get LOP with a Carb...

Last edited by smokyray : 05-30-2018 at 03:04 PM.
Reply With Quote
  #35  
Old 05-30-2018, 03:31 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,572
Default

Quote:
Originally Posted by smokyray View Post
Higher RPM at low altitude with a capability to achieve rated RPM at high altitude was always the better call as desired overall performance at lower altitude was achieved as well.

A parallel valve LYC IO-360 is rated at 180HP at 2700RPM, engine mods, high comp pistons and blueprinting notwithstanding.
Inflight, to achieve higher TAS you need to fly higher, therefore a good FP prop will allow you to run wide open above 10,000 feet. For Carbs that's good as the carb throat is most efficient with the butterfly valve (throttle control) streamlined in the slipstream. For fuel injection the same efficiency applies, especially cold air induction.
People often wonder why their fixed pitch prop RV is slow compared to others (or the perf. #'s quoted by Van's)....

This little tidbit from Smokey is the key.

If you choose a prop pitch to make your engine act the way it did on the C-172 or Pipe Cherokees you have flown, you will not have good performance (climb or cruise).
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #36  
Old 05-30-2018, 04:00 PM
johnbright's Avatar
johnbright johnbright is online now
 
Join Date: Aug 2010
Location: Newport News, Va
Posts: 182
Default New Whirl Wind "HRT" prop for O-320 and O-360 under 200 HP

Quote:
Originally Posted by JackZ View Post
Johnbright
Call whirlwind and ask for bill. He will give you some info on the new prop that is being tested now.Less machining steps and simpler. HRT style blades for a better performance prop
Jack
I spoke with Bill Koleno at Whirl Wind Aviation. They have been working on a new HRT type blade for O-320 and O-360 under 200 HP. Lots of testing has been done and an announcement may be made at Oshkosh 2018. It will pull harder on takeoff compared to the 200RV. The hub is the same and the blade ferrules will be machined from a smaller piece of stock for incremental improvement in machining time and material waste; Bill did not mention a design change to the ferrules; number of machining steps is the same.
__________________
John Bright, RV-6A 25088, at FWF
O-360, 8.5:1, vert sump, SDSEFI EM-5
Z-14 adapted for EFI, wiring and IP CAD files here
Newport News, Va

Last edited by johnbright : 05-30-2018 at 06:00 PM.
Reply With Quote
  #37  
Old 06-03-2018, 12:17 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 2,699
Default

Quote:
Originally Posted by Reaver View Post
This will be almost my exact setup: keep it light, only prime the parts that need to be primed, IO-360 (180hp) and a Catto FP prop. The main difference is that I'll be using the RV7 more for XC flight than aerobatics; just the occasional light roll, etc. What was/is your fuel burn at that 11,500' and 2650rpm WOT? I was just assuming that I would want a cruise pitch, but am open to being convinced otherwise.
I also have an underpitched catto, but with an IO-320. I always cruise WOT. At 8000' I turn 2740 while LOP and burn about 8.1 GPH for 164 Kts. At 10,000, I am turning 2720 and 7.7 GPH for the same speed or 1-2 Kts slower. At 12,000 I am down to 2680 and about 7.4 GPH. Stock cowl and fairings.

Larry
__________________
N64LR
RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress

Last edited by lr172 : 06-03-2018 at 12:31 PM.
Reply With Quote
  #38  
Old 06-12-2018, 01:08 PM
Chattin35 Chattin35 is offline
 
Join Date: Jul 2014
Location: Boise, ID
Posts: 214
Default CS Prop FTW

A prop extension is req'd for a SJ cowling which changes your G tolerances - limiting your aerobatic/formation cushion and fun factor. IIRC, adding the 4'' extension reduces max G to +4G's. Also, some people end up adding weight up front to move the CG fwd with a composite prop, negating the composite weight adv.

Braking in the traffic pattern... Fixed pitch props are going to be much harder to slow down. Not an issue in FL at sea level and flat terrain. But, if you're in the mtns and have to kill some altitude and hit your spot on a grass strip while skirting a ridge, it's very nice to have that extra drag. It's also nice to be able to make 2700 RPM on take off role out of, say Telluride, at 12,000' DA. I may not attempt that take off with a fixed pitch prop. Not an issue with a CS.

Same thing for formation flying. A CS prop is way better for braking (overruns, flying with slow a** Cessnas, etc). I'm not sure what Smokey is talking about there. A CS prop is dramatically more desirable for formation flying given the extra braking power and control of the engine available.

In cruise... I have a bone stock RV-7 and IO-360-M1B and I can open it up to 2700 RPM and make similar numbers to the "best" RV-7 mentioned above. Or, I can dial the engine back and run at lower RPMs with higher compressions for a more efficient, and comfortable (noise), cruise than you could with a fixed pitch.

Also, I spoke with someone very high up at Van's (*cough) and he told me that later RV's really needed a constant speed prop to get the most out of them.

The -7 was designed around the aluminum Hartzell CS prop. The weight and balance comes out perfectly. There are no RPM or G limits. And, you have much more control of your engine and performance in all phases of flight.

Going with a CS prop was probably THE best decision I made as a builder. Originally, I was going to go with a used engine and Catto 3 blade to save money. But, I'm soooo glad I ponied up an extra couple thousand bucks for the CS. For the RV-7, there's no comparison.

As you can tell, I have a strong opinion on this .


Last edited by Chattin35 : 06-12-2018 at 01:13 PM. Reason: Added picture.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 07:36 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.