First replacement part order

2of5 · #1 03-15-2017, 06:07 AM

I got my workshop finally set up and tools in hand and decided to take a look at the -7A empennage kit that I picked up last October from a gentleman who started it but only got so far before life got in the way.

He left it at the "HS needs only to be deburred, primed and assembled" stage, but looking at the two HS-702s I thought something was amiss with the relief notches

After seeing other examples online, I decided to scrap these two parts and use them for practice, along with the existing spar doublers. I ordered two new spars and doublers, which shipped yesterday.

So, can it be said that these spars were not airworthy?

goatflieg · #2 03-15-2017, 06:34 AM

Umm.... wow. Just... wow.

jcarne · #3 03-15-2017, 06:36 AM

You are correct not what I would consider air worthy (not enough edge distance on some holes). This is definitely a tricky area though. I had to rework this area not once but twice! This area gave me an intense amount of grief but eventually got past it. You may also want to check the HS-00005 ribs (where it meets the spar doubler) as the holes may not have edge distance on those either. Lastly I would check edge distance on both HS-710 and HS-714. Hmmmm is it bad or good that I have all those part numbers memorized... haha

jcarne · #4 03-15-2017, 06:39 AM

Also, looking at the spars again, the flange was cut too low into the radius and there is in no way shape or form enough angle on the existing flange, those will almost definitely interfere with HS-00005.

tyconnell · #5 03-15-2017, 07:16 AM

Later, in that area, there's a step where you are assembling a front spar, a rib "coming in from aft", and the angle you have to fabricate (sorry, I don't have the part numbers). Edge distance is tricky as you need to get it right going through 3 pieces. I'd definitely read up on that before attempting it. IIRC, I failed the game of "Van's says" in that area, 2x, and should have waited until later ("Van did not say to drill yet").

bscycleman · #6 03-15-2017, 07:31 AM

Good catch. If the kit did not come with the doublers, older kids did not, now would be the best time order and install them.

Brian

wirejock · #7 03-15-2017, 08:05 AM

I see that often on here.
The pilot hole for those relief notches should be drilled right in the vertex of the flange and web. Prop it up at a 45 degree angle. Center punch the mark then drill a small hole before moving up to 1/4".
In the meantime welcome a day have some fun with the scrap parts.

2of5 · #8 03-15-2017, 09:08 AM

Quote:

Originally Posted by bscycleman

Good catch. If the kit did not come with the doublers, older kids did not, now would be the best time order and install them.

Brian

Thanks. It's not even a year old, so it came with them already. I ordered new ones to replace the existing drilled ones.

2of5 · #9 03-16-2017, 06:58 AM

Quote:

Originally Posted by wirejock

I see that often on here.
The pilot hole for those relief notches should be drilled right in the vertex of the flange and web. Prop it up at a 45 degree angle. Center punch the mark then drill a small hole before moving up to 1/4".
In the meantime welcome a day have some fun with the scrap parts.

Thanks for the tip Larry!