Flap handle notched plate
- Thread starter The Kid
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Grant
FRIEND
At Work.....
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aktango58
FRIEND
18AA
Anything interesting you have learned and want to share?
Yes, if you have time, please share "interesting". I have the P-Stol flaps and need to figure out what benefits I can get at where on the ratchet positions. Like should the first notch match the max down aileron etc.? I know the stock flaps, on my plane, wanted to be at two notches to facilitate short take-off on floats. But now, on wheels, full flaps and hold the stick back is the shortest take off. You can't "see' where you are going but it is short. Just move all the rocks and logs and holes beforehand.
WhiskeyMike
MEMBER
West Boxford MA
Some of the Husky guys towing banners notched them so you could get right at about 14-15' for max lift before inducing drag at 20'. 10' was too little, and 20' too much. I could never figure out why no-one thought of that?? PA-18 seemed a bit different for some reason and didn't help as much with flaps for lift - though it was a better tow plane. Wing attach angle? Smaller flaps? Same with the L-19. Sweet spot when flap was just visible in the rear window about 13-14'.
My flaps are 112" and my plane has lots of power. Working together I like more than normal flaps for takeoff. 45* works well. I trim full nose down so when power comes up the tail comes up. I pull the yoke back to fly and relax back pressure as trim comes to neutral for whatever speed I want. Electric trim makes this pretty simple to do. My flaps have always required a great deal of effort to pull on. I can pop the flaps to takeoff but to get past 45* has the flap handle at vertical and that's a very awkward position. Awkward to pull on or ease off if there's a load on the flaps. To land and get past 45* flaps requires being really slow and at the point I can get the flaps out more there isn't any advantage as I'm only a couple of feet above the ground. In practice I could get that slow up higher and come in much steeper, and I will, but that's not everyday flying. More often than not I'm dealing with some element of a crossing wind and the associated burble at the treetops. I tried adding more notches to stairstep them on in smaller bites but that didn't help much. I've always been a fan of full flaps for landing so most of my tinkering has been to get the best compromise for deflection of flaps with practical effort. My first notch is just to get the flap handle into position so I can grab it while sitting up straight. Beyond that I have 4 notches but primarily only use three. My next arch will reduce the 5th notch deflection and subsequently the 4th notch a bit as well. Takeoff with 4 and hopefully be able to pull a little more for landing than I'm getting now.
Bill Rusk
BENEFACTOR
Sandpoint, Idaho
Thank you Stewart. Just a heads up for you PStol (Keller) flap guys......if you pull them on at high airspeed they will bend your flap hangars. These flaps have a lot of lift and thus create a lot of stress on the attach points. Get SLOW before you pull on the flaps, and get them off before you get too fast after take off. I would recommend the white arc to start at about 60 for the first notch and below 50 for additional positions. This will be somewhat self-correcting, as Stewart noted above, it will take a lot of force to deploy the flaps at higher airspeeds.
Hope this helps
Bill
Hope this helps
Bill
Bill, please correct but being that the PSTOL flaps are certified, does that mean the standard white arc for Vfe as listed in the TCDS remains the same or did they require a change per the paperwork that comes with those flaps?
If flap hangers are at risk of being bent above 60 in real world operations it’s puzzling that they made it past the testing phase for certification with a Vfe of 80-85.
Just thoughts,
Merry Christmas all!
Oz
If flap hangers are at risk of being bent above 60 in real world operations it’s puzzling that they made it past the testing phase for certification with a Vfe of 80-85.
Just thoughts,
Merry Christmas all!
Oz
When Back Country started building the Rev 2 with long Keller flaps the target was to get 70° of flaps. To get that much flap travel from a conventional flap handle required using bell cranks with one long arm. We owners quickly realized the mechanical disadvantage made flap effort exceptionally high and at flying speeds the flap deflection couldn’t be maintained. Mike and I reinforced all the flap pulleys and increased cable tension. One owner broke flap pulley welded attachments off the airframe. The fix was to modify the bell cranks to equalize the arm lengths. Flap effort is still higher than normal and travel is reduced to about 55° max. Flap effort prevents me adding flaps until below 50 mph. It used to be 40. Pulling them on at higher speeds is possible but the effort feels like it would cause damage. Common sense leads me to avoid it. I’d expect the same in any other airplane that uses manual flaps. Forget the top of the arc and feel the airplane.
frequent_flyer
Registered User
Arizona, USA
Perhaps somewhat related -
Do any Cub-like aircraft have different Vfe for the intermediate flap settings? It seems obvious to me that, if the structure will stand Vfe at full flap, it must be able to stand higher speeds with reduced deflections.
CubCrafters did not answer when I asked what Vfe was for one notch of flap on the FX-3.
skywagon8a
MEMBER
SE Mass MA6
A simple answer is, they just had no desire to spend extra time and money only to come up with more data which would be marginally useful. Flight testing and engineering costs money.
RaisedByWolves
FRIEND
Tx
If I remember right there is a new placard for 70mph full flap extended speed.
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frequent_flyer
Registered User
Arizona, USA
Yes, I know that, they paid my salary for many years. Not sure about marginally useful though. Lots of aircraft have higher Vfe for first notch of flap deflection.
skywagon8a
MEMBER
SE Mass MA6
Yes they do. How important is that on a Super Cub?
frequent_flyer
Registered User
Arizona, USA
It could make the difference between requiring a full structural inspection and not needing one for an inadvertent Vfe excedance due to late retraction after takeoff.
frequent_flyer
Registered User
Arizona, USA
My question was not specific to the Super Cub. I asked about "Cub-like" aircraft. The FX-3 will easily exceed Vfe in a climb with flaps not retracted. I expect the same is true for several other Cub-like aircraft.
Anyway, I'll assume the answer to my question is "no" unless someone with a Cub derivative says otherwise.
Crash Jr.
Registered User
Anchorage, AK
Certified STC'd PSTOL flaps are placarded for 70mph Vfe like others have said. Lots and lots of flight testing determined that was a safe speed for the certified versions at stock length and max deployment angle of 51 degrees. What's being discussed here is longer experimental PSTOL flaps with potentially increased flap deflection over what is standard for a stock PA-18. In the cases of experimental flaps all the certified stuff is out the window and you, the builder and pilot are responsible for coming up with the safe operating limitations for your flaps.
Thanks Bill; it is a good thing to keep in mind that if you do venture into setting flaps up for more deflection or very long lengths that the Vfe number is much lower than on a certified -18.
Steve Pierce
BENEFACTOR
Graham, TX
70 mph on certified and they have a full length block inside the flap hanger and thick doublers riveted to the false spars at the hangers which are not included in the experimental version. I have installed 10 plus certified sets and not seen an issue on any of them thus far. I have screwed up and pulled them to fast on mine before but try not to make a habit of it.
