Hangar Flying

Hangar Flying => Hangar Flying => Topic started by: propblade on July 01, 2013, 09:42:11 AM

Title: Starting work on a partially completed LGEZ
Post by: propblade on July 01, 2013, 09:42:11 AM

After years of hemming and hawing, reading and researching, I came across a Long project from a friend of a friend; he has built one and is flying it, then started a second with a partner, but the partner backed out. Anyway, I got the project home and did a survey of the project, comparing to the plans and my best judgment on the workmanship. Everything seems in order and decent construction. It appears that the bulkheads and fuselage sides were done using Aeropoxy (guessed because of the red tint), and the floor done with West System (since it appears uncolored). The project is a few years old, so the details from memory are fuzzy. All layups appear to be on the correct schedule.

My only issue that I found is that the F28 bulkhead was not installed prior to cutting the canard shelf. The top longeron and doubler were cut flush with each other. The measurements I took show the cut to be at 6.4" aft of the forward face of F22. A 0.5" thickness F28 would bring the dimension to the correct 5.9". My concern is this, though: the F28 would have to be bonded to the flush faces of the top longeron and doubler; it would not be notched to fit under the top longeron. Would there be any problem with this? I realize that after shaping the top of the fuselage, there is not much of the top longeron left in that notch, and the doubler is where the canard alignment pins fit, so flush bonding F28 as I described should be ok. Or, should I cut back the longeron 10-12", splice in a new section and install F28 per plans? As I see it, F28 is just to contour the nose into the canopy, there is no critical supporting structure relying on F28, correct?

Also, the distance between both longeron ends is about 0.6" wider than what F28 would be. Should I try to draw the longeron ends together while F28 cures in place, or would making F28 wider to fit be acceptable, so long as I translate that increased dimension to the canard for the alignment pins?

(unable to attach pics at this time; will add when able)

Title: Re: Starting work on a partially completed LGEZ
Post by: dkreidel on July 02, 2013, 10:36:55 PM

I've built three EZ's but the last one was completed in '89 so my memory is foggy. There is no problem with the slightly wider dimension across the longerons and I would accept what you have and  modify F28 and location of the canard tabs for the pins. You may have some compromises on the canopy outer mold line near the fwd corners with the wider longerons. Make sure you retain appropriate edge distance from the pin center line to the outer mold line  - the pins only take the control input reactions; primarily pitch but also roll.

Dick Kreidel

Title: Re: Starting work on a partially completed LGEZ
Post by: propblade on July 03, 2013, 04:50:26 PM

Thanks! I figured a way to narrow the longeron gap: 36" bar clamp, with a ruler underneath clamped stationary to the F22 bulkhead to gauge the distance of both longerons' travel. I will have to make the layup a total of 1/2", so it may be a little heavier than plans.

In other news, I have to cut out most of the control passages in the bulkheads still. Once that is done, what becomes of the bare foam in the holes? Does it get cored and filled with dry micro, a couple plies of BID laid over them, or left bare? (This may have been mentioned in the plans or CP's, but like any other time you look specifically for something, it has a propensity towards hiding.)

Title: Re: Starting work on a partially completed LGEZ
Post by: dkreidel on July 03, 2013, 07:44:52 PM

Bare or a little micro slurry on the bulkhead cut outs - no glass req'd

Title: Re: Starting work on a partially completed LGEZ
Post by: propblade on July 04, 2013, 12:21:44 PM

Wonderful! Thanks for the guidance!