Spar Blemishes

[rcbif]

Good Morning all.

Was wondering if anyone here recently got a kit to compare to spar parts I got recently.

I'm replacing the spars on my kit (dont ask, long story :( ) and just got my new spars in with my firewall forward.

First off - the crating was very impressive. The long crate was stiff as could be, no shipping damage, and the parts were nicely separated inside the crate with special foam with zero wiggle room or moving parts.

Unfortunately during my inspection I found gouges on each spar that are beyond able to be buffed out. I would guess some as deep as .008.

After I inspected the tubes, I looked at the I-beam I inserts and noticed each has a deep indentation running lengthwise. It is deep enough to grab a fingernail and not slip - Maybe .015 or more. It looks to me like a blemish in the extrusion process but I could be wrong?

I just wanted to get some opinions here. Has anyone else seen stuff like this? Am I being over critical? 2399023991239922399323994

[PapuaPilot]

First, you need to talk to the factory if the damage was present when you received the shipment. Nicks and gouges in any critical / high stress parts need to be addressed. Have them look at the pictures you took.

As a general rule nicks and dents are typically allowed to be only 10% of the wall thickness of the part after blending.
Also, it might be possible to blend out the nicks and place the damage at the outboard end of the wing where the stresses are lower.
IMO the groove in the extruded I beam shouldn't be a problem.

Check with the factory.

[Dave S]

RC,

I had one damaged as received spar from the old skystar company with similar gouges to what you have photos of - photo attached. That one was replaced on warranty at the time - skystar sent a new one and didn't want the old one back - sent them the photo - no problem. My belief is the current ownership of Kitfox is far better than the old company and I am certain they will take care of you if you recieved a messed up part.

Here's the deal - IMHO - when building a new airplane, we want new parts in new condition. It is true that there are acceptable limits as defined in the FAA's AC 43.13-1b "Acceptable methods, techniques, and practices - aircraft inspection and repair" and a person can use those limits for damaged parts, but you do not have a new part then - you have a repaired part. We are not talking about repairing a 10 year old airplane.

I was fortunate enough to have had an acquaintance in our local EAA chapter who spent a lifetime inspection and repairing aluminum on DC-9s for Northwest (when there was a Northwest). He was my go-to aluminum guy. That individual was pretty clear on two things - do you want to build a new airplane with repaired parts? and more specifically, a transversal scratch/gouge of any depth on a spar is a weak point in the structure - even if you clean it up if within limits, it's not as good as an undamaged part.

I don't want to venture an opinion on the I beam - I am not familiar with that particular type of deformation.

[rcbif]

Thanks for the comments. I took some videos and will be sending them off Monday along with some pictures to Kitfox. My pictures show the worst, and there are lesser marks like yours too Dave. In fact, running my hand down lengthwise inspecting them, I ended up embedding some chips into my fingers.
I imagine it's hard to prevent damage to these things between the actual manufacturing, handling, shipping to Kitfox ect., but like you said and John M. Has told me in the past, it all comes down to aircraft standards.

[jiott]

I personally would not accept those spars, unless the damage is way out on the ends.
The groove in the I-beam insert is in the web near the neutral axis where there is nearly no bending stresses; would be no problem for me.

[rcbif]

Update from e-mails with Kitfox

Kitfox says the groove on the spar inserts is a indicator of a new die being used, so it is supposed to be there. They should be good to go (for any future builders that may come across this)


The spar tubes however -

To me these looks like marks from a rack, being slid on an edge, or rough handling. I was told they are from the extrusion process. It was also mentioned that the above scratch is mid-wing, so the spar insert makes that area ridged.
If you enlarge the picture, you can see the depth of these marks compared to the .003" tape.

24041

It was recommended that I use a drill with scotchbrite pad to buff this out, and then measure the tube diameter. Based on the picture, I estimate .010 at the minimum will need to be removed to eliminate the scratch.

As Dave S said, this is beyond prep-work - it is repair work on something I was hoping would have brought me that peace of mind.

[N14ND]

Back in '95...
I rejected two of the aluminum tube spars. Had Skystar send me two new tubes. They did. The new spars still had some marks but were acceptable. I still have the old ones. I think the problem lies in the manufacturing process and shipment to Skystar (Kitfox). I don't think that there is care and concern from the tubing manufacturer when they are stacked, boxed and shipped to Kitfox. My personal opinion is that they left Skystar that way. I received them wrapped in foam.