5,6,7 Wing rib part numbers

[jmodguy]

Anyone know if there are any differences in the wing ribs other than the part number stamped on them? (27001 and 27002)
I stared at them for quite a while and could not see any difference.
On another note - anyone have a spare 27002 rib laying around?

[bumsteer]

I'm sure someone will correct me if I'm wrong. 27002 has thicker web (6mm vs 5mm) and 27002 has aluminum doubler for flaperon hinge

[Dave S]

Jeff,

Our S7 kit came with 18 each part number 27001 ribs. These were described as 5mm.

[jmodguy]

bum,
I'll take my calipers to the hangar tomorrow. I couldn't see any difference but I did not have anything to measure precisely with either

Dave
You do not have any 27002? I am building a KF 5 and it calls out the 27002 for hinge point ribs.
Thanks for the input

[bumsteer]

Jeff

Yeah I know they do look alike. Can't talk to the later models but on my 5 the big thing is the aluminum doubler for the hinge.I know the hinges are different on the 7. I don't have extra 27002's. Good luck.

Rick

[Dave S]

Jeff,

The inventory sheets called out only 27001....no 27002 parts were indicated. 27003 and 27004 were the R & L buttribs, but that was the only other 27XXX series parts.

Our ship was an early S7 - might be that there were some variations depending on the point in time when the kits were made.

[jmodguy]

Took my fancy Harbor Freight digital caliper to the hangar after work and the webs are the same thickness at 5.35mm on both part numbers. I'm guessing they are the same.
As for the hinge doubler, I do not think they came installed on the 5 ribs.
The owner before me (I'm #3) updated the flaperon hinges to the 7 type.
Thanks Dave and bum

[bumsteer]

FYI I checked my rib webs and there is a 1 mm difference. Also the doublers were factory installed on my 27002 ribs. Kit was purchased in 1998. Series V Outback. Obviously yours are different.

Rick

[jmodguy]

bum
I'm not sure what happened but the kit was ordered in 1995 and was a 1400 GW Safari. The spar tubes have .065 walls so that means they are the 1550 GW wings. Must have been some trading or upgrading going on somewhere in the 20 yrs before I picked it up.
I am going to assume these ribs are good to go due to Daves input that his ribs are all the same p/n.

[VP-22]

Hey Jeff: Never saw a final word on the rib question. I just bought a used kit and half my ribs are 27001, the other ones are unmarked and identical. An AP friend said i could reinforce the rear web myself with wood just to be safe. Bruce

[jmodguy]

Some have a reinforcement doubler on the inside of the cap strip at the rear spar location. I am not sure if this was factory or by builder. I don't have access to my hanger right now because they are painting the hangars. I'll see if I can get to my manual tomorrow or this weekend.

[jmodguy]

22
Went to the hangar and grabbed by build manual. It calls out the 27002 as flaperon ribs or "odd number" ribs. After reviewing the document, it looks like the builder adds the upper and lower cap strip rib reinforcement at the rear spar at step 12.
Sounds like they only use one part number now.
You might want to check the web thickness as previously mentioned. Put the thicker webs at the hinge locations, with the re-inforcements and you will likely be ok.

[VP-22]

Thanks Jeff: I am proceeding as follows: Using the 27001's as even numbered ribs. The unmarked ribs I'm using for odd numbered ribs #1 - #9 . To those I will add the plywood doublers (step 22) and aluminum backing strips (step 23).

As it turns out my kit is missing those alum backing strips (pt. #22908) Can I make them myself? I know the length (4.8in) and width (3/8in) as per manual. But what about thickness. I can get alum at the local hardware store that is 1/16 thickness (I think.) Will that do it? Has anyone micro'd the thickness of their strips? Many thanks - Bruce VP-22 - New Bern, N.C. Sure would like to make contact with a local Kitfox builder/flyer in ENC!

[efwd]

.065". Im sure you could make these. I am not sure but the material is pretty stiff. It resembles the 6061-T6 aluminum sheet that I bought for a new electrical tray I made. I used .050" thick for the tray. Aircraft Spruce sells it in 2x2 sheets. I bet they have .065" also. The trouble I would have making these is the radius on my factory parts is much tighter than what I would achieve using my Harbor Freight sheet metal bender. It will require the tight radius in order for the rivets to land correctly on the flange and not have the radius involved. Im sure Kitfox will sell these at a reasonable cost.

[bumsteer]

Bruce

FYI I didn't see you mention what model you have. On my Series 5 there is a doubler on the top and bottom of the rib for the flaperon hinge. Mine have been covered with epoxy varnish so it was hard to get an accurate reading but I would say it averaged .030. The 5 has the hinge on the top and bottom. I'm pretty sure Eddy is building a 7 and the flaperons are hung different with what I believe is one hinge the top. You should probably check with John or Debra at the factory to determine the best way to go depending on your model. Part numbers may have changed over the years but on mine P/N 22908.000 shows FS Al2024-T3 .020;.4x48. I got the quick wing option so I can't confirm this is what was used for the doubler.

Rick

[VP-22]

Thanks Rick:
I have a 4-1200; manual says 1992. I appreciate the measurements and advice. I spoke with John on Monday. The parts (#22908) cost $3, less than the shipping so I thought why not make them myself. John didn't have the exact specs (on hand) thus my inquiry here. I've since decided to order them. Seems it's not as easy as it first sounded, as efwd pointed out, and as a first time builder, I've got my hands full just assembling this wing let along making my own parts! I did install the plywood doublers today, so that's progress! And yes, thanks, John was very clear about the difference between the 7 and Classic IV flaperon hinges, pointing out that you can't use the 7 hinge on the older wing set up. I guess that hinge has advantages over what I have and some people adapt it somehow. Anyhow, I just emailed in my order and added some Hysol to justify the shipping.

Bruce

[jmodguy]

Bruce
you can use the newer flap hinge (Series 7). My Series 5 came with both and the previous owner installed the newer hinges.
The aluminum double is prob .030. I'll check my parts manual and let you know.

[VP-22]

Jeff:
That will be good to know, thanks. I found some stock alum but would have had to cut it length wise, problem #1, and wasn't sure of thickness, problem #2. Didn't want to risk the rivets pulling through if too thin or not seating properly if too thick. Truth be told, my manual doesn't show a clear view of the backing strips and I wasn't sure if I'd fab them correctly anyway. Best to be safe. Debra hooked me up: $6 for enough to do both wings. Maybe when I get them I'll feel foolish for not making them myself but this is a huge learning curve for a former ultralight guy. Bruce
At this point my anti drag brackets/tubes are clecoed in place, ribs prepped and notched. Waiting to install alum backing strips before I can proceed with reassembly and epoxy of all pieces.

[bumsteer]

Bruce

Maybe this helps13594

Rick

[VP-22]

Great shot. I assumed it went all the way to the end of the cap strip. Now I see otherwise. Very helpful - thanks.

[avidflyer]

If my memory is correct, at least with my Kitfox 4, I think it said to temporarily mount the flaperon attachments before you cover the plane. Drill all the holes then. It would be real lousy to have a poor glue joint and push the aluminum backer off the cap strip with the wing covered. JImChuk

[VP-22]

I agree JImChuk. Reading ahead, it says that after the wings are covered you relocate the holes by melting a hole in the fabric with a soldering iron. Yeah, that's my biggest fear that something should comes loose.

Back to the aluminum backing strips. In my manual, page W-A-19, Fig W-A-23, it appears in the (vague) diagram that the piece behind the upper cap strip goes all the way to the end of the rib. In Rick's picture it stops short, roughly even with the end of the bottom strip. Not saying it was done wrong, just wondering why it doesn't go to the end. Is it due to the way the brackets are shaped? Thanks

[bumsteer]

Bruce

Just to be clear, my kit was from 1998 and this is a factory rib. I didn't install the doubler. I assume it doesn't go to the end because the 6 (3 top/bottom) rivets used to install the hinge are all over the capstrip and therefore the doubler. May have been done different on the 4. Heck it may be different from year to year.

Rick

[Dave S]

For some additional reference - the attached photo shows how/where the aluminum doublers were placed on our early version S7 (early 2000's).

The instructions called for bonding and riveting the doublers through the rib web.

Guessing that there may be variations depending on when a kit was originally built.

[mr bill]

Mine is done the same way. KF4 2002 vintage.

[VP-22]

Wow, great pics all. Thanks; much more clear and yes done the same way in terms of the top piece. Maybe the mailman will bring me my parts today!

[bumsteer]

Need to correct my last post. Can't count. There are a total of 8 rivets (4 top/bottom) on each hinge half. My Series 5 does not have the 5th rivet through the trailing edge.

Rick