Author Topic: lower wing attach fitting differences  (Read 2171 times)

391stol

lower wing attach fitting differences
« on: May 17, 2015, 12:25:28 PM »
At what time or serial # did helio change there thicknesses on the lower steel wing attach fittings  from .250 to .350?  It was somewhere in the 391b stage.   

Doug Johnson

Re: lower wing attach fitting differences
« Reply #1 on: May 22, 2015, 09:51:41 AM »
My wild guess is that when c/n 075 was being converted to a H-395 to develop Helio Mod no. 045 between 06/58 and 09/58 it was first applied which would be around the time c/n 083 was started.

Or possibly when c/n 044 was authorized by the factory to operate in category 8 at 3400 lbs 07/56 ?
« Last Edit: May 22, 2015, 09:57:50 AM by Doug Johnson »
Doug

jmetzler

Re: lower wing attach fitting differences
« Reply #2 on: May 23, 2015, 08:45:12 PM »
SN 037 and on all used the same part number lower fitting. That makes me suspect that 037 was the change point for the thickness difference. It appears to be lower than 037 anyway. Jim

Doug Johnson

Re: lower wing attach fitting differences
« Reply #3 on: May 23, 2015, 10:43:57 PM »
Jim,
Your post reminded me of Helio Mod no. 21 (replace all landing gear, and structural modifications to increase gross) c/n 032 and up, gross wt increased from 2800 to 3000 lbs (TC amended) previous c/ns require replaceing  all landing gear, and structural modifications to increase gross)

I have never found anything that spelled out what structural changes were made. Do you have any thoughts on that?

Maybe Mike Hawkins will mic the lower attach fitting on c/n 036 project if it is still convienient for him to do so.

Doug






     
« Last Edit: May 23, 2015, 10:58:18 PM by Doug Johnson »
Doug

jmetzler

Re: lower wing attach fitting differences
« Reply #4 on: May 24, 2015, 06:32:40 AM »
I don't think wing fittings were included in the modification though, if that's what you are wondering; SN 001 had the 3000 gross weight with mod 21 and kept the thinner fittings. I don't know if I or we have the details of Mod 21 or not. Jim