Windshield/cowling fitting question

[Jerrytex]

I am fitting the the windshield to my KF 4 and have some questions. I have the LP aero windshield so it is preformed. However, there is trimming required. Is there a certain distance the windshield needs to be away from the spar carry through tube? I can change this distance quite drastically. Also, do the side edges of the windshield go over the posts that the tabs are welded on or does is stop where the tabs are welded to the posts? The corners of the upper and lower cowling stick way out. See pic. I took the windshield off and they still stick out. The cowling has sat for awhile so it's possible that it might have taken a "set" in the position in how they were stored. Any ideas on how to make them line up. Any suggestions on the windshield too?

1729

1730

1731

[cardinal flier]

The rear of my top cowl also wouldn't lay flat against the lower cowl. I added one additional cowl fastner as far to the rear as I could. Watch for fuse chassis interference the the additional fastner. I've seen this problem on other Model IV's. Bruce

[Gary]

I recently fitted the stock lexan windscreen to my model 4....what a chore!
Mine was trimmed for a 1/8"" gap around the carry through tube.
The sides go almost all the way to the rear of the door posts.
Some of the tabs were bent with a block of wood and a hammer to eliminate the gaps to the windshield, added some epoxy filler to tabs that weren't flat against the inside of the windscreen.

I Used a heat gun to soften the cowl corners and reshape them so they lay flat (wear thick leather work gloves). You have to bend the corners too far and then wait for it to cool before letting it go. It took a couple of tries to get it perfect, I plan to lay up one layer of light weight fiberglass cloth on the inside of the corners to lock them in place.

Gary

[DanB]

Danger Will Robinson...the heat gun is an ok trick with the polycarbonate, however, if you have an acrylic windshield and do this you are asking for trouble. Others can chime in here as I know we have some pro polymer folks (hi papa). The acrylic tends to be touchy as it is best worked when it is evenly heated. Some have said they have done this, but there seems to be a fine line between enough heat to bend and too much. If you go over that line your acrylic will craze (get lines in it). I also understand that it's a good idea to get your hanger as warm as you can to work the install.
my 2.5 cents due to inflation

[Av8r3400]

(I think he was saying he was using the heat on the fiberglass cowling parts, not the windscreen.)

I would agree with it being a BAD idea to heat the formed plexi windshield.

[Jerrytex]

Thanks for the ideas. I think I'll try the heat gun on the fiberglass. I tried to shape the cowling in the sun yesterday but could not get enough heat. I am still gonna have to do some thinking on the windshield. I am going to shim the top up about a 1/4" on the butt rib so there is plenty of clearance when the wing swings in place. Does this seem about the right amount? The 90's manual is so vauge and almost no pics.

[DanB]

(I think he was saying he was using the heat on the fiberglass cowling parts, not the windscreen.)

.

Yea, my bad... that's what happens when you read and try comprehending all at the same time in the AM :rolleyes:

[GDN]

You can use a heat gun but before you have to put the Lexan in a drying room.

[Lion8]

Windscreen fasteners question. Would it be ok to place soft rubber washers between the windscreen and the tabs on the fuselage ? These would act like shock mounts. Could this same idea be used on the fiberglas cowlings?
Good-Bad idea? Thanks for your reply's. - Lion8

[HighWing]

Regarding the position of the windshield fore and aft, I would suggest that you might want to position it so the curve approximates the location of the leading edge of the whing so the wing root fairings will be smooth and small. The LP windshield I fit on the Series V, I am helping with was an early version and didn't fit well. As a result the fairings - currently working on them - are not ideally shaped.

Back to the heat thing, It apparently is possible to tweek the acrylic windhsield with heat as the quote below is from the LP folks. As we were installing the windshield on the Series V I have been helping with, problems prompted a fitting question to LP and this was part of thier reply. A note - We didn't use the heat gun as we found another way to correct the problem we had. So can't give any tips there.


I can talk you through using a heat gun to bend the acrylic slightly to fit, however, the acrylic has a memory and it remembers the flat sheet. It may do some forming that you do not want, if it is overheated or improperly heated.

Lowell

[cap01]

when drilling the holes for the fastners , be sure they are oversized and the fastners arent too tight as to allow the windshield to grow and shrink with temperature change and sun . as for applying heat , id be very careful , not much room between being warm enough to bend and melting . id have to do some serious practicing before i tried heating my windhield .

[DBVZ]

One other comment. I have been shopping for a plane, and recently walked away from a deal in part because the cowl ran up over the windshield at least 4" higher than necessary. Forward vision is obscured enough without loss of another 4" above the panel.