VintageBonanza Forum

[lejambcr]

The flap gap doors on my 1947 Bonanza are becoming a continuing source of maintenance headaches, broken springs...etc. The piano hinge pins are nearly impossible to remove on the longer(middle) doors. I have seen some airplanes that have had their flap gap doors permanently fixed in the streamline position. Is there a service bulletin or other generally accepted modification or 337 to accomplish this. Any info you could provide would be helpful. Thanks, Charlie
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Charlie

[Bryan Wells]

I'm not sure if I am understanding this correctly, STC's are available for Flap Gap seals that are attached underneath the wing at the point where Flaps or Alerons attach, but these are fixed stips of sheet metal that cover the gaps and I am not aware of any with piano hinge that would have movement. In your message you refer to them as flap gap doors? Maybe I'm just confused, do you have a photo to show this?

[lejambcr]

The very early Bonanza's, mine for instance, had hinged doors that sealed closely to the flaps when retracted. Then with flaps extended, the spring loaded doors 'flopped' up into the wing to form a 'slotted flap' system. I believe Beech discontinued use of this system with the 'A' Model. Beech advertised these as being worth 2-3 MPH in the original press releases, but obviously felt the maintenance problems weren't worth the effort. Charlie
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Charlie

[budowa_cepa]

I agree with that.
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[Bryan Wells]

I think I see what you are referring to. Here is a scanned page from the parts manual. Looks like items 9, 10, and 11 are the items of interest.

www.vintagebonanza.com/pdf_files/flaps.pdf

These were only on the Model 35 up to serial number D-1115 as indicated in the Beech Parts Manual. Not all Model 35's would have had them. If they are a problem, you might could change out to a later model configuration as Beech did and reference that in the log book. I don't recall a SB to address this. But if they worked, I probably wouldn't change them, yes it is one more maintenance item to address.

[lejambcr]

I talked to Beech Customer Service. They found a listing for a kit #35-525 that contains the brackets and other assorted hardware, including drawings to fix these spring loaded flap gap doors to a stationary, streamlined configuration. My only problem is finding one of these kits..........Charlie
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Charlie

[Bryan Wells]

Jan 6th, 1948, Service Letter #15 and kit 35-525. I found a listing for that number. Did Raytheon supply you with the Service Letter? I would bet the kit components could be owner produced parts. Raytheon should be able to profide the engineeriing drawings or kit contents. The Service Letter may show it. I don't durrently have access to my early Service Bulletins and Service Letters, but let me see if I can find someone who does.

[lejambcr]

Bryan, thanks for your help on this. I did talk to Beech Customer Service. The don't have any kits in stock, nor do they have copies of the Service Letter or any Blueprints! I found one kit #35-525 in the USA and bought it. You don't want to know the price! Charlie
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Charlie

[Cepelin]

Ditto.
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