VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #11  
Old 12-15-2019, 10:03 AM
flyinga flyinga is offline
 
Join Date: Dec 2007
Location: Fredericksburg, TX
Posts: 662
Default

If even remotely thinking about formation flying; CS.
__________________
Jim Averett
RV-8
TS36 - Silver Wings
Fredericksburg, TX
Reply With Quote
  #12  
Old 12-15-2019, 11:28 AM
RV7 To Go RV7 To Go is offline
 
Join Date: May 2011
Location: Ontario, Canada
Posts: 263
Default

Welcome to one of the never-ending debates!

As others have said...it is critical to define your mission first. The decision may be simpler after that.

CS is typically heavier. CS has better TO performance. Both have almost the same performance in cruise, as has been documented on the forum in the past. I fly a FP 7 and have confirmed this with other CS RVs on our field. One other benefit to the CS is in slowing the plane down. The CS is like having air brakes. With the FP you have to be more aware of your energy management. There is more complexity and maintenance with CS.

One thing not really discussed is the maintenance. There is more to inspect with the CS prop and controls. CS according to the manufacturer requires an overhaul at specified time or hourly intervals. Can be expensive. In Canada FP metal for Certified requires 5 yr corrosion inspections (not sure what the US requires). Costs much less in time and money. You can debate whether or not to do it on a homebuilt.
__________________
Al
___________
RV4 - Bought 2013 Sold 2017 after 450 hrs
RV7 - Built in 6.5 yrs & Flying 2017
Reply With Quote
  #13  
Old 12-15-2019, 11:30 AM
Plummit's Avatar
Plummit Plummit is offline
 
Join Date: Apr 2010
Location: Covid Country-SoCal
Posts: 1,081
Default

Quote:
Originally Posted by flyinga View Post
If even remotely thinking about formation flying; CS.
Really? Why? I thought the idea was to use the throttle the most, but I'm not a formation flyer.

-Marc
__________________
RV-10
N814RV
2020 Donation Made
Reply With Quote
  #14  
Old 12-15-2019, 11:43 AM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,652
Default

Quote:
Originally Posted by Plummit View Post
Really? Why? I thought the idea was to use the throttle the most, but I'm not a formation flyer.

-Marc
You still use the throttle but the speed of the airframe reacts quicker due to the governor adjusting blade pitch. This is generally a good thing but one should be aware of the limitations on counterweighted engines concerning the prop "driving" the engine. Using the prop as an "airbrake" is a bad thing on some engines.
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
Reply With Quote
  #15  
Old 12-16-2019, 07:28 AM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 1,558
Default

Formation with a fixed pitch prop works out fine. You just need a little more ?talent?/anticipation. Energy management takes on a new level of importance.
__________________
SH
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2016/sold/2017
RV8/2018 built/Sold(sadly)
RV4/bought 2019 Flying
Cincinnati, OH/KHAO
JAN2020
Reply With Quote
  #16  
Old 12-16-2019, 07:55 AM
YvesCH YvesCH is offline
 
Join Date: Feb 2015
Location: Basel, Switzerland
Posts: 203
Default

Quote:
Originally Posted by flyinga View Post
If even remotely thinking about formation flying; CS.
Don`t tell this to Luca and Franz from the Formation Aerobatic Team CrewRV8.. They both have a 3 bladed fixed pitch Catto Prop?

(and this was the reason why I chose one too. Its simpler, lighter, cheaper and if they can fly formation aerobatics it is good enough for me... )
__________________
-----------------------------------
Yves - Basel, Switzerland
RV-8 #83458 HB-YUA
Donation 2019 done
Reply With Quote
  #17  
Old 12-16-2019, 11:59 AM
breister breister is offline
 
Join Date: Dec 2006
Location: Atlanta, GA
Posts: 1,231
Default

A Corvette will start in 4th gear, and can attain nearly its maximum velocity on level ground in 4th gear. Would you buy a Corvette stuck in 4th gear?

Many of us do exactly that. You don't "wear the clutch out" because the clutch is air, but you do pay a climb penalty and don't have as many power / rpm choices (your power gives you whatever rpm it gives you, you can't run full power / lower rpm).

Like any nice feature, the trade offs are complexity and cost. If money is no obstacle, a Cessna Caravan will do just about anything any RV will do and carry passengers too...
Reply With Quote
  #18  
Old 12-16-2019, 12:09 PM
airguy's Avatar
airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,145
Default

Quote:
Originally Posted by Toobuilder View Post
You still use the throttle but the speed of the airframe reacts quicker due to the governor adjusting blade pitch. This is generally a good thing but one should be aware of the limitations on counterweighted engines concerning the prop "driving" the engine. Using the prop as an "airbrake" is a bad thing on some engines.
Only as far as the prop driving the engine, but that is true. Pulling the power back far enough to put the pitch on the fine stops but not yet driving the engine (9 or 10 inches MAP) results in really good drag to slow the airplane.
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
Reply With Quote
  #19  
Old 12-16-2019, 12:52 PM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,652
Default

Quote:
Originally Posted by airguy View Post
Only as far as the prop driving the engine, but that is true. Pulling the power back far enough to put the pitch on the fine stops but not yet driving the engine (9 or 10 inches MAP) results in really good drag to slow the airplane.
If only all pilots had that level of awareness and finesse. Based on what I hear in the pattern and from word of mouth, there are a lot of people chopping the power and "throwing out the boards".
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
Reply With Quote
  #20  
Old 12-16-2019, 01:56 PM
Mark33's Avatar
Mark33 Mark33 is offline
 
Join Date: May 2010
Location: Baton Rouge, La.
Posts: 753
Default

Quote:
Originally Posted by Toobuilder View Post
If only all pilots had that level of awareness and finesse. Based on what I hear in the pattern and from word of mouth, there are a lot of people chopping the power and "throwing out the boards".
My method may be a little unorthodox, but I basically come in to the pattern the same whether I?m flying a F/P or a C/S.

I come screaming in to downwind at a fairly low altitude and fairly tight to the runway. When I?m abeam the numbers I pull power and pitch up. By the time I?ve climbed back up to a proper (normal) approach altitude I?ve bled off enough airspeed that I can then push the prop full forward without ever increasing the RPM?s. Then basically, all in one motion, I?ll kick her around and turn from downwind to base to final. The C/S will then act as my air break and I can almost point the nose straight down and still be going slow enough to deploy two notches of flaps all while keeping the RPM?s in a normal range.

If I?m flying a F.P. my procedure is exactly the same, other than not being able to point the nose straight dawn on final..... my final approach has to be a little bit flatter to keep the speeds where I want them.
__________________
Mark H.
RV-7- IO-360, EFII, Whirl Wind C/S, (Built and sold)
RV-4- O-320, Catto three blade, P-Mags (Sold)
RV-8- IO-360, Hartzell C/S (Flying)
RV-7- (Building)
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 01:39 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.