VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 05-04-2020, 03:34 PM
GHARBEN GHARBEN is offline
 
Join Date: Nov 2019
Location: Gainesville, Georgia
Posts: 51
Default No Full Flaps?

I have been flying N12HR for about 4 months. Wonderful fun airplane. Very hard to slow down on landing.
This RV 4 will only use its first notch of flaps. It pops out of the second notch immediately when you pull the flap handle up to the second notch.
Any thoughts?
Takes a lot of slipping and tail wagging to make a 180 approach!
Must fix it!
Reply With Quote
  #2  
Old 05-04-2020, 03:59 PM
Mel's Avatar
Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 11,226
Default

Quote:
Originally Posted by GHARBEN View Post
I have been flying N12HR for about 4 months. Wonderful fun airplane. Very hard to slow down on landing.
This RV 4 will only use its first notch of flaps. It pops out of the second notch immediately when you pull the flap handle up to the second notch.
Any thoughts?
Takes a lot of slipping and tail wagging to make a 180 approach!
Must fix it!
Re-make the flap "notches". And while you are at it, add another position.
first notch = 15?, second notch = 28?, third notch = 40?. This will give you the optimal take-off position.
__________________
Mel Asberry, DAR since the last century. Over 1,000 certifications accomplished. Discount for Veterans, Law Enforcement, Fire Fighters.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
Reply With Quote
  #3  
Old 05-04-2020, 06:44 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 2,022
Default

Not sure there?s room for three ?notches?. On my RV4, I moved the front seat aft almost 3? and the seat back angle is where the notches are. My seat back is now closer the the fulcrum. I had 3 positions before moving my seat back (two notches - no room for three), now I have two positions (one notch), up and down. He may have a different flap setup. Mine was built (not by me) according to plans.

The OP definitely needs to remake his notches. They should be built with a negative slope, both on the flap lever and on the notch piece riveted to the seat back angle. This holds the flap lever in the selected position, reinforced by air loads on the deflected flaps.
__________________
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
RV6/Used kit purchased 2021 building
Cincinnati, OH/KHAO
JAN2021
Reply With Quote
  #4  
Old 05-04-2020, 09:36 PM
Jvon811's Avatar
Jvon811 Jvon811 is offline
 
Join Date: Mar 2014
Location: KFNT Central Michigan
Posts: 224
Default

Ya, my flap handle will pop out of full flaps in my airplane quite often... Seems to be getting worse with this quarantine, eating all the time. Seems to happen a lot after the holiday season too. I need to start running and exercise again...
__________________
-Justin

RV-4 N249P
O-320, Dual P-Mags, Warnke Prop, Short legs, Manual Flaps, GRT Sport EX
Reply With Quote
  #5  
Old 05-05-2020, 06:36 AM
fixnflyguy fixnflyguy is offline
 
Join Date: Jan 2006
Location: Winston-Salem, N.C.
Posts: 1,467
Default Be Careful !!

My recommendation is fix it soon..there have been some situations that went bad when they popped up going slow to land, and it can be aggravated with a backseater that bumps it with a foot. You should easily be able to replace the detent/notched piece, or do what I (and many others) did and install electrics..I built mine with them from the start after riding backseat in a friends with manuals. I have my flap up/down buttons on the top of my stick grip, and can control them without taking a hand off anything. Its just natural to be looking out the canopy in the pattern turns and see the flaps going down without reaching/looking for a switch or lever...way easier when a go around call is made too.
__________________
Bill E.
RV-4/N76WE
8A7 / Advance NC
Reply With Quote
  #6  
Old 05-05-2020, 08:15 AM
HFS HFS is offline
 
Join Date: Aug 2009
Location: Lemoore, CA
Posts: 386
Default Flap Handle

This may or may not have any relevance to your problem - I see that your airplane was finished in 1991 and was probably started in the middle to late '80's.

The callout for the (early S/N's) flap handle (Drwg. 34) was for a 1 1/4" x 3/16" 2024-T4 aluminum flat bar. This handle, with a 2" offset to the left, proved to be too "flexible" to operate satisfactorily, especially at higher airspeeds - it would "twist" badly and make the maintenance of flap position somewhat suspect.

A lot of us upgraded this part (and stop blocks as well) to a 1/4" thick bar, and reduced the offset to 1", reducing the torsional load on application. There were instances of passenger's left foot "bumping" the flap handle (when engaged) causing it to release the flaps. We also "biased" the handle a bit by bending it slightly inboard to insure that it "wanted" to mate with the stop blocks when being operated.

Also, as other responses have indicated, a re-establishment of the "angle" cuts for the stops as well as the (mating) one on the handle should be made. Van's drawing doesn't call out the mating angle directly, but I scaled it at 30* - both the fixed "stop" as well as the mating section on the handle need to be maintained at this angle for good operating characteristics.

With the original flap handle at 3/16" thickness, and the grip with a 2" offset to the left, application caused a CCW twist that moved the bottom of the handle away from its mating stop block. Sometimes (especially after a bit of wear) the two surfaces would not align well enough to guarantee flap operation. Getting rid of some of the torsional load & stiffening the handle by increasing its thickness seemed to help. I flew my -4 almost 1700 hours and didn't have any issues with the manual flaps with the mods mentioned above.

As I said at the beginning -none of the above may be relevant to your situation, but is a bit of a history lesson on this particular part.

YMMV

HFS
Reply With Quote
  #7  
Old 05-05-2020, 10:04 AM
smokyray's Avatar
smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,968
Default A notch up...

Quote:
Originally Posted by GHARBEN View Post
I have been flying N12HR for about 4 months. Wonderful fun airplane. Very hard to slow down on landing.
This RV 4 will only use its first notch of flaps. It pops out of the second notch immediately when you pull the flap handle up to the second notch.
Any thoughts?
Takes a lot of slipping and tail wagging to make a 180 approach!
Must fix it!
Hey GH,
I built and started flying my Four back when we had to shoo Dinosaurs off the taxiways to go fly. The RV4 plans (if you built yours)have a great description and drawing of the front seat back flap notch block the handle seats into when you lift it.
If the notches are small per the plans, I found that final approach speed faster than 60 Knots would "pop" it out of the second notch, hence retracting the flaps. Being an F16 Pilot, I'm good with it as it does essentially the same thing with hydraulic pressure.
So...
I started experimenting with slower approach speeds which took practice with my Sterba "big bite" wood prop. I found that slowing to 65Knots (70mph) on downwind and trim almost full aft the RV4 would get into a "groove" where you control aimpoint with pitch and sink rate with power. At 60 Knots, power on and a fairly nose high approach the airplane would not float and you literally could fly it right to the ground, flaps fully extended.
The best part was my flaps stayed down and I could now quickly retract them for proper STOL quick stop technique. I also made a few small adjustments to my flap handle to keep it where I put it, mainly filing it with a more pronounced notch.
Email me offline if you have any questions...
V/R
Smokey

smokyray@rocketmail.com
Reply With Quote
  #8  
Old 05-05-2020, 06:34 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 2,022
Default

I agree with Smokey. I?ve also filed a more aggressive notch on my flap lever and the new notch I made when I moved my seat back aft. Also, my flaps down stall speed is about 48k and clean break is at about 53K, so 65K is a safe initial approach speed (1.3 VS.). Max flap extension speed is 87K (100 mph) on my airplane. Getting the flap lever into my one and only notch (35*), takes a pretty good pull at that speed, but if I do it at that speed, it stays there. Slowing to about 60K as I cross the end of the runway results in enough reserve energy to flare with not too much float. I can dump my manual flaps in about 1 second for a really nice short field landing.
__________________
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
RV6/Used kit purchased 2021 building
Cincinnati, OH/KHAO
JAN2021
Reply With Quote
  #9  
Old 05-06-2020, 12:37 AM
johnf_1 johnf_1 is offline
 
Join Date: Nov 2012
Location: santa rosa
Posts: 75
Default Flap handle retention

Hi Scott:

I riveted .063 on the outside of the block to act as a keeper. It hangs down about 1/16 so the handle is captured under load (in the hanger, it is useless). The uncommanded pop out is highly undesirable.

Up on to my soapbox: the manual flap control is positive, and instant whether deploying or retracting. Maintenance is non-existent. Failure modes (besides pop out!) are few. And....people go for the push button electric flaps. Not sure why. And there you have it!


My pattern speeds: 80 downwind 65 base 60 short final. My ancient round airspeed and brand new Dynon Skyview put the light vso at 43-45 KIAS. I have ample bouyancy at 60.
John
I can send pics of my mod if you want. Lemme know. John N95JF
Reply With Quote
  #10  
Old 05-06-2020, 06:51 AM
BruceMe's Avatar
BruceMe BruceMe is offline
 
Join Date: Feb 2005
Location: Shawnee, Kansas
Posts: 817
Default Go electric

I realize this thread is about fixing the notches. It's pretty easy, just make them sharper, I've done it. But consider switching the flaps to electric. There's so precious little room in that cockpit for a big handle that gets in the way of the GIB's feet (not that I actually care).

I did this conversion nicely on a 6 and my most recent RV-4A already has it. On the -4 you weld one extra tube to the flap control. The new tube drops into the center bay near where the elevator push tube connects to the rear-seat control. It's off-center to avoid all those elevator tubes. You can use a 3" throw linear actuator and it looks really simple. Put ticks on the flaps at 10, 20 & 30 degrees and you have a position indicator.

I can send pictures.
__________________
Bruce Meacham

Building RV-4A 18ZM
Built/Own RV-4 254MM
First RV RV-3 3456B

VAF annual donation on autopay
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 12:24 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.