Flap Mod Kit/Oshkosh plans

[Keven]

My A&P just installed the flap mod kit on my 337A. A few questions:

1. What are the realized benefits of this mod;

2. Any detriments to using the mod?

3. What is the normal cost for the kit;

4. How long should it take to install it;

Thanks,

Keven
________
Lovely Wendie99 (http://www.lovelywendie99.com/)

[SkyKing]

Keven,

Sounds like you put the 'cart before the horse'... these are obvious questions one would ask before having the work done. Is the flap mod an AD requirement, or something in a service bulletin applicable only to the 337A?

SkyKing

[Jerry De Santis]

SkyKing, What do you want from hime---He's a lawyer!!!
Hello Keven
Cheers
Jerry

[Bob Cook]

Jerry

Don't get Skyking in a "flap"..........

Never heard of a "flap mod". Think someone is pulling someone's leg.

Skyking.......come to OSH and join the party. Good excuse to clean the engines.

bob

[Keven]

Skyking, Jerry, and Bob, et al:

Background:

Let me give further explanation which was intentionally omitted in my original message due to time contraints (toddler stuff).

I originally lost power to my flaps last August (stuck in retracted position). My A&P was able to fix the problem by replacing the flap down limit switch.

I lost power to my flaps again in February. I was in Charleston, SC and they were stuck down just barely (appx 3 degrees). I messed around with the motor, checking connections, etc. without success. Then I went to the switches up front. I messed around with those (Bob, you'll have to excuse my overly technical terms, please try to keep up with me), checking for connections, current to them, etc. However, one of the times that I manually made the switch, the flaps completely retracted, which I considered a good thing! (There was no current shown on the meter getting to switches after I was done messing with the switches, but it retracted anyway.) So I flew without flaps.

After I got back to GMU, I took it to my A&P, who informed me that the flap motor was shot and not worth trying to rebuild, and that I probably just got lucky with the switch getting some current after I jostled the motor around a bit (brushes or something made contact again). He then told me that there was a mod for the flap system which I needed to get.

NOW, remember, this was in February, BEFORE I knew of this board, any of you, or any other Skymaster owners. In addition, he has always been honest and pretty fair with me, and I still have no reason not to trust him. So, with that disclaimer given, I proceed proclaiming my ignorance.

He said that he had to order the system, but it took3-4 months to get. He installed the motor which works with the new system (but still didn't give me operational flaps because it was for the new system only, not my existing) and I waited. (Yes, flying without flaps since February makes you appreciate them once you have them again.)

I got the call a couple of weeks ago that the parts were in. So, he installed them, it works great, but it was, in my simple, small and cheap mind, very expensive. $800 parts and 26 hours labor.

So, with that background . . . .

Skyking: Not only is the cart before the horse, the horse is out of the barn, etc. But, you takes 'em as you finds 'em. As explained above, I would have asked the question long ago if I would have had the benefit of this board in the infancy of my Skymaster ownership. Unfortunately, I didn't, which makes me appreciate this board more than I can adequately articulate here. Skyking, probably the best part about this is that now hopefully you have some sense of retribution after my wiseguy JFK comment:) We even? Truce?

Jerry: As always, thanks for pointing out the obvious;) As I have consistenly shown, I need as much help as I can get!

Bob: I hope you're wrong, which I find usually NOT to be the case. My physician specifically informed me during my last medical exam that neither one of my legs needed to be pulled. I asked him twice to be sure. If they were pulled, there's chiropractic trouble abrewin. I haven't received my logs back yet from the A&P. I'll let you know what I find out from the entry.

In the meantime, is anyone familiar with this type of problem and /or alleged fix for flaps? GMAS, Kym, anyone?

Hope this helps.

Keven
________
Hot Box Vaporizer (http://hotboxvaporizers.com)

[Bob Cook]

Keven

Why would I pull your leg(s)? Leave that up to your other half <G>.

Now flaps. Yes the motor could be burned out.... but.... it is more likely the follower cable that provides feedback from the flap actuator to the flap switch. There are two microswitches that when the follower cable moves the indicator it eventually will hit the either of the microswitchs under the instrument pane and shut off the flap motor much like the cowl motor/flap setup (end stop). This give the proportional control or positioning of the flaps.

Part of the problem is the outside portion of the cable being plastic starts to break off and introduces "slop" in the feedback to the switch assembly. You can see the flaps do not retract all the way up and gets worse with time (symptoms). You then need to replace the cable and re-align.
They just deteriorate from age and heat (another reason to hanger the AC).

The motor is very reliable and I rather doubt the motor burned out. You would have smelled something or the breaker would have "popped". (personal opinion)

Still have no idea there was a "mod" for the flaps. I sure cannot find an SB or other bulletin from Cessna.

GMAS ? do you know anything about this ?

The cable replacement is probably 4-5 man hours depending on complexity of aircraft. Cable is about $100 more or less. I replaced mine last year with same problem.

For others, if you inspect the cable at the flap motor end, look for the connection to the outside of the boden cable assembly. The outer jacked will be slipping and most likely starting to break in pieces. There is a form of clamp over the rubber sleeve that holds the cable in position. It is located up in the headliner 2/3 back in the ceiling on the pilots side. Little tricky to get at. Make sure this is lubed each annual (by the book).

Ready for Osh Keven?

Fyi

Bob

[Keven]

Bob:

I'm working on the kitchen pass for OSH, and am close to receiving one. Did you guys ever decide if you're camping, staying at a hotel or what?

I'll advise on my status upon more info.
________
Children avandia (http://www.classactionsettlements.org/lawsuit/avandia/)

[kevin]

Bob, I and my friend Carlo are camping. Others have talked about attending, but it is hard to keep up with status. The latest that I (think) I know is on the calendar page of the site. I need to update it, so anyone that is coming that is not on this page, or if any of the information is wrong, please let me know. I plan to make an expanded OSH planning page later this week.

Kevin

[Bob Cook]

Planning arriving Tues or Wed morning. Camping with the "boys". It's a hoot! No CNN is worth the price of admission alone.

What is a "kitchen pass". Free food ? <G>

You do not need a pass for the showers...........


Bob

[WebMaster]

Bob, you weren't looking well enough. Remember Keven has an early 337, and A model
Quoting from the history page:

In an effort to increase the downwash over the horizontal tail for minimizing nose-down pitch with flap deflection and increasing elevator power for landings, a unique differential flap travel arrangement was installed in the early production airplanes. Those flap sections between the fuselage and booms would be deflected 40° while the outboard flaps would be deflected to a maximum of 25°. This worked very effectively. However, an ice-laden C-337 making an instrument approach at night in Cleveland, Ohio experienced a sudden nose-down pitching motion when the flaps were extended. This resulted in a crash into a home near the airport which was survived miraculously by all occupants of the airplane. It was apparent that an ice build-up on the leading edge of the horizontal stabilizer could not tolerate the increased localized downwash angle due to 40° of flaps. Thus the underside of the tail stalled, causing the loss of elevator control when the airplane pitched downward.

Since it was inappropriate to install a deicing boot on all C-337s, a decision was made to simply remove the differential flap feature. Cessna Service Letter 65-43 dated April 19, 1965 stated, "to improve the stall characteristics of the Model Super Skyrnaster, the inboard flap travel has been reduced from 40° to 25°. This change provides for a much smoother stall recovery under a gear down, flap down and partial power configuration." This was a mandatory change that involved the modification of the existing inboard flap bellcranks, replacement of the existing flap push-pull rod, and adjustment of the rods, bellcranks, and cables

Just an FYI

[Bob Cook]

A-1 Larry

Now I do remember. That mod goes back a long way and I thought that all AC had been covered.

Thanks for the info.

bob