Repairs & Mods: custom cowl, new gear,etc

100 posts in this topic

Posted

Nice looking cone. Keep your eye's peeled for a used Shop Smith. I see at least 3 a year being offered for less than $300 bucks and most have all the  add on tools. The last one I seen on Craigslist was being offered for $150 dollars. I'm tempted to get rid of my old drill press and put an older Shop Smith in it's place just to have the  variable speed on my drill press.

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Posted

Here's a interesting link for those thinking about spinning a spinner out of metal.  https://www.youtube.com/watch?v=JgRLWAPgD7s

I mentioned people buy wood lathes such as yours and add riser blocks under the head and tail stock to get the clearance needed for spinning. I've seen them take the wheels out of an old pair of roller blades and use them to make spinning tools. After watching the video it will be a little more clear how the roller blade wheels are used. You don't want 6061 as a material for spinning. There are other grades that work better for spinning.

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Posted

Here's a interesting link for those thinking about spinning a spinner out of metal.  https://www.youtube.com/watch?v=JgRLWAPgD7s

I mentioned people buy wood lathes such as yours and add riser blocks under the head and tail stock to get the clearance needed for spinning. I've seen them take the wheels out of an old pair of roller blades and use them to make spinning tools. After watching the video it will be a little more clear how the roller blade wheels are used. You don't want 6061 as a material for spinning. There are other grades that work better for spinning.

ok i didn't realize what you meant by spinning before just thought you were talking about being able to make a larger diameter plug. I have seen a video of someone doing stuff like that and wrote it off as something i wasn't going to try but now i'll give it some thought. 

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Posted

9CAF6439-CE01-4E7E-A3EA-640C013E835D.thu10 dollar spinner... I got a 12 cm half sphere iceream mould of the web  https://www.cerfdellier.com/5235-calotte-demi-sphere-inox-de-buyer.html?gclid=EAIaIQobChMIlpXnlen23gIVDvlRCh1H7QvZEAQYDCABEgLOL_D_BwE#/498-taille-o_12_cm Perfect snug fit on the hub plate, drilled a center hole and spray painted it. 

Much faster than starting from scratch. Have you played with Solidworks? It's got some great features to calculate how efficient that spinner/propeller combination is. Here's a link to a YouTube video that can explain what I'm trying to convey: https://www.youtube.com/watch?v=a4lAhFsls5k&t=163s

 

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Posted

Well for better or for worse i cut the cowling in half and removed the top part from the mold.  Couple reasons, first off i only recently found out how dangerous it is to leave the air filter uncovered so that moisture can get in the engine. I reached in the intake and wrapped some plastic around the filter but not very well. Now i can secure it better. Hopefully the last couple months hasn't destroyed my engine. Fortunately utah is pretty dry usually but we've had 2 or 3 periods of damp weather during those 3 months it was uncovered. Second reason is that i hope to take it to get the new gear brackets welded on soon and a 60 mph wind might have ripped the whole cowling mold off.

I never added the last 2 plies that i previously mentioned that i was planning on. I'm going to see if adding some stiffeners will be adequate. Maybe a little more work and might be a little on the flimsy side but less weight. It feels really light which I'm happy about. 20181201_001854.thumb.jpg.9bd0eddc55d982

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Posted

"Damn... I made that!"

Grabbing a beer and saying that  to ourselves is part of the reason we are all so nuts about this money sucking - grown up kids hobby!  

Nice job!

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Posted (edited)

"Damn... I made that!"

Grabbing a beer and saying that  to ourselves is part of the reason we are all so nuts about this money sucking - grown up kids hobby!  

Nice job!

Thanks, but it's a long way from done. But I'm more and more convinced that it's not going to end up in the dumpster.

tonight's progress was getting the rest of the cowl off the plane and into my basement shop, so I'm finally not freezing my hands off working on it:20181201_205020.thumb.jpg.ae375369d72ae4

doing the preliminary trimming:20181201_235429.thumb.jpg.a5639ad2137fa6

There are an awful lot of bubbles in this thing. Glad it's not structural or it would be in the dumpster. 

And started getting ready to install the joiner strip between the 2 halves20181201_235440.thumb.jpg.4c2279a0b8620e

I'm using duct tape again as a mold release. 

 

I managed to get the lower half of the mold to come with the cowling when i pulled it off the plane. Some of it will get cut away but it helps the part hold its shape and not deform under its own weight.  I'll need to post cure it at some point.20181201_204954.thumb.jpg.5773dfba52aea5

And you'll notice that i managed to save the circular area around the hub which will help when i join it back together to lay up the joiner strip between the 2 halves. 

 

And we all know the job isn't official until you've shed some blood on it:20181201_205900.thumb.jpg.751194967db75eyes that's really my blood. 

 

Edited by Willja67
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Posted

Ok guys I'm looking for opinions here on 3 subjects:

1. Right now the cowling is in 2 pieces, top and bottom. I'm considering cutting the top piece in 2. So one piece goes from windscreen to firewall and the other just covers firewall forward.  Right now I'm leaning towards not just for simplicities sake. 

2. Is somewhat related, how many access doors do i need? I figure i'll need to check rotary valve oil and coolant level, but do i even need that? With the wingnut style camlock fastener i can have the top of the cowl off in 2 minutes or less, so again for simplicity I'm leaning towards not. 

3. Should i install some windows in the lower cowl between the door and firewall?

In one of Trent Palmer's videos he had a prop strike and in the aftermath added windows in this location  (about the 6 minute mark). Do you guys think that's worth it? Does it give any appreciable added visibility? I'm a bigger guy and my legs are fairly thick and i wonder if I'd even be able to see out the window if it were there. 99% of my flying will be solo so having the window in the other side might be worth it. His other mod of a forward looking backup camera does seem like it's a really great idea. 

 

Anyways you guys that have experience operating these planes I'd like to be your thoughts. 

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Posted

I kind of like having the boot cowl as one piece, and the top and bottom ahead of the firewall in two pieces.  Then it's pretty easy to pop off the top of the cowl and have a look at everything.  Maybe  a piano hinge and long joining pin holding top and bottom of cowl together would speed up the removal as well.  If all is good, coolant level and rotary valve oil levels shouldn't change, but of course you wont know that till you've run things for a while.  JImChuk

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Posted (edited)

I kind of like the two piece no boot cowl solution. Here are my reasons:

1) lighter

2) less complex 

3) boot cowls make working behind instrument panel and thru the firewall a giant pain in the ass.

4) boot cowls make windscreen harder to replace unless boot cowl is removable too, but then what is the benefit of the boot cowl?

Boot cowls do look cool and may provide a bit better fire protection, but that is debatable since it is all fiberglass anyway.

The builder of my Fat Avid did it up as a boot cowl. I converted back to two piece and am super happy I did.

 

Edited by Chris Bolkan

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Posted

I really need to learn the lesson to not overthink things too much and just go ahead and do something. I spent a week and a half wondering what the best way to temporarily join the 2 halves back together so i could lay up the joiner strip and originally was going to use popsicle sticks with dabs of bondo but that stuff takes too long to set and i finally realized that hot glue and foam had worked well since i started the project and it worked just fine again.

I'm going with the 2 piece cowl. Right now the slight inconvenience of very slightly limited access is far outweighed by ease of construction and however many ounces of weight i'll save. 

20181211_203912.jpg

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Posted (edited)

When i grow up i want to be Mike Patey.

 

Here are a couple videos on his Wilga Turbine conversion that could be part of a master class in working with composites and particularly of interest to me in building my cowl. I wouldn't ever want him to see this he'd just shake his head, but hopefully it'll do for my poor little 

 

 

I couldn't really separate my cowl like he did his because i couldn't get it off in one piece and i used duct tape instead of the thinner foil tape he used, but the exterior of his cowl was much more finished than mine, so i can add a little height with the micro slurry when i finish it. 

But here is a pic of laying up the joining strip on the left side of the cowl:20181226_223600.thumb.jpg.f37decb60b8c22

I wetted out 5 plies of fiberglass on plastic cut it out and peeled 1 side of plastic off and used the other to keep the whole mess from becoming a unusable mess until i had put it in place inside the cowl. As per the video i cleaned the surface then "basted" epoxy onto it to get in the pores then after it was all in place i covered it with more plastic and worked the squeegee to get the resin to bridge between the joiner strip and the cowl so hopefully the edge of the strip won't peel up like some of the plies on the cowling. 

Edited by Willja67
Added video
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Posted

20181227_215028.thumb.jpg.79c255cfd1302eright side joiner strip layed up.

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Posted

Here's a interesting link for those thinking about spinning a spinner out of metal.  https://www.youtube.com/watch?v=JgRLWAPgD7s

I mentioned people buy wood lathes such as yours and add riser blocks under the head and tail stock to get the clearance needed for spinning. I've seen them take the wheels out of an old pair of roller blades and use them to make spinning tools. After watching the video it will be a little more clear how the roller blade wheels are used. You don't want 6061 as a material for spinning. There are other grades that work better for spinning.

I have a book from the early 1900's on spinning metal.  I really want to try it some day, it looks like a lot of fun.  When I got a lathe and a mill, I was looking for books to learn how to use them properly.  All the ones I could find were from the early 1900's, and man are they disorganized and hard to read.  Technical training books have come a long way since then!  Most of the ones I found were free on Google books.  I wonder if that Google project has died or is still working?

Mark

 

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Posted

Here's a interesting link for those thinking about spinning a spinner out of metal.  https://www.youtube.com/watch?v=JgRLWAPgD7s

I mentioned people buy wood lathes such as yours and add riser blocks under the head and tail stock to get the clearance needed for spinning. I've seen them take the wheels out of an old pair of roller blades and use them to make spinning tools. After watching the video it will be a little more clear how the roller blade wheels are used. You don't want 6061 as a material for spinning. There are other grades that work better for spinning.

I have a book from the early 1900's on spinning metal.  I really want to try it some day, it looks like a lot of fun.  When I got a lathe and a mill, I was looking for books to learn how to use them properly.  All the ones I could find were from the early 1900's, and man are they disorganized and hard to read.  Technical training books have come a long way since then!  Most of the ones I found were free on Google books.  I wonder if that Google project has died or is still working?

Mark

 

The Google book project is alive and well. Link here to the book your probably talking about: https://books.google.com/books/about/Metal_Spinning.html?id=wUuDAAAAMAAJ

There was a guy that sold a series of videos years ago on spinning, not sure where mine are at the moment but as they say a picture is worth a thousand words, the videos are an excellent way to get an idea of what the books are talking about. I have not hunted but You Tube has to have something on the subject these days.

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Posted (edited)

I finally split the cowling again. 20190106_210759.thumb.jpg.9dd71270d365cenot shown was making fastener locations and using 3/4" lathe screws to hold the top to the bottom. Ive stripped out most of the mold and marked the flange for trimming. My prep and cleaning must not have been enough because about 6" of the flange peeled off with moderate pull. I'll have to re epoxy that20190106_215312.thumb.jpg.ad5859db628f1bhere you can see all the lathe screws holding the top and bottom together. I was smart enough to mark the camloc locations in the lower cowling so reattaching was fairly painless although at least one on the other side is in the wrong place, you can tell as the cowling wants to bulge out until the fastener is released then it sits down nice and flat. 20190106_215330.thumb.jpg.92cbbd33d1d0c2I made amistake making the mold. You can see the cowling drops below the bottom of the fuselage a couple inches. The stock cowling doesn't. I'm wondering if I'm going to blank my radiator and have to lower it. I was hoping to reduce drag with this cowling not increase it.20190106_215617.thumb.jpg.bcd8354027b991you can see the cowling is definitely peaked on top, kinda like me. The flat parts either side of the peak are very flimsy so i think i'll build it up with dry micro for a better contour and then lay another layer of glass over that to stiffen it up.20190106_215452.thumb.jpg.235d568f790817Not sure how visible it is but there's about 3/8" between the cowling and the top of the firewall. This happened because the white foam used to make the mold was 3/16" thick, so the camlocs are pulling the cowling tight to the side of the plane and so the middle is being pushed up aggravating the fact that the 3/16" foam that wrapped around the firewall also isn't there.20190106_220356.thumb.jpg.aeca1d70373027Again not sure how easy this is to see but I pulled out all the lathe screws except the front one and let the cowling settle at the back end and it hangs down about 3/8" below the original parting line, so I'll trim it tapering from that 3/8" at the back to nothing at the front.  Probably still have to do something to seal the firewall but at least it'll be a much smaller gap to seal 20190106_215319.thumb.jpg.69aabdac2f5050paying more attention to little details while prepping and laying up the fiberglass would have saved me a lot of work right now fixing all the bubbles and other imperfections but all in all I guess it's not too bad for my first real foray into composites. 

Edited by Willja67
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Posted

I think you will be very happy with the two piece approach. You mentioned previously the two piece might make things a bit harder to access. Not true. the two piece approach is by far the best for accessibility to everything and makes everything much easier to work on. Looks great. That is a huge project you have undertaken.

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Posted (edited)

Next project started, fairing the outboard leading edge strut attachments.  Living at 4500 Msl where the density altitude can go over 7000 in the summer and reading all the comments about how fairings help with climb rate i decided to start working on that as well. VG's are in the plans as well. 20190112_173621.thumb.jpg.b997bab264a059That's the same white foam under the duct tape that i used on the cowl. It bends nicely when it's warm but cracks when it's cold.  I'm going to use drywall mud and sand it smooth before i glass it.

20190112_173609.jpg

Edited by Willja67
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Posted

Also got the top half of the cowling marked and trimmed. I was actually surprised how well it fit after trimming.20190112_204020.thumb.jpg.a5515854280e6ayou can see the trim line on the bottom, between 1/4-3/8" on the aft end tapering to nothing at the front.

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Posted

20190119_104835.thumb.jpg.8ae81f5c4a185fBungees and hardware just arrived. One step closer to having the brackets welded on and getting this girl on her new legs. Still have to save some pennies for the wheels, brakes and axels. I was hoping to use the axels i have but the link George Happ at Matco sent me were for 9" axels and the ones I have are 6.5-7".

20190119_104623.thumb.jpg.05f0f9308fd31cI'm also building a plywood deck for the trailer to mitigate some of the risk of the tailwheel jumping the track again and doing further damage to the plane. 

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Posted (edited)

Talked to George Happ today and learned that the Matco A8 axel http://www.matcomfg.com/AXLEASSEMBLYA8-idv-2555-1.htmlwhich is 9" long is meant to be cut to length depending on the installation. So that's $150 that can be spent on something else. Now i can arrange a firm time to get the brackets welded on and the new gear installed!:BC:

Edited by Willja67

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Posted

20190621_224108.thumb.jpg.39d6b6edc53ed5

The wings have been hanging on the wall far too long. Just made these:

20190621_223953.thumb.jpg.24375bd51e7f69

 

Time for 1 to come down and get the rib tails reinforced and i think the paint job is a little boring so I'm going to spice that up as well. Also going to tear into the gas tank and see about making it a little more serviceable

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Posted

Let's get this party started!20190629_133730.thumb.jpg.4a39c0406e972b

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Posted

Cargo area?  I know the KF1 wasnt designed with a dedicated cargo area like later models but I figure some  of you guys have used one to haul some stuff? So how did you do it? 

I'm not looking to haul the kitchen sink around just maybe enough for a night or 2 camping trip to one of the nicer backcountry strips. 

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